Genomes require physical boundaries to separate active and repressed chromatin, a function traditionally attributed to insulator proteins. Here, we demonstrate that genomic insulation is also a physical property encoded into the DNA polymer. In C. elegans, transcription-coupled mutational bias remodels Helitron transposon minisatellites to match the DNA helical repeat. This intrinsic curvature pins supercoiled DNA into nucleosome-depleted plectonemes, creating mechanical barriers that partition chromosomes into gene-sized regulatory domains. Constrained by DNA mechanics, this structural strategy has evolved convergently across Metazoa into a shared mechanical code at Drosophila insulators and human CTCF sites. Strikingly, active human LINE-1 retrotransposons encode a similar plectoneme structure. Thus, sequence-encoded mechanics represent a universal solution to transcription-silencing conflicts—a topological barrier harnessed by host genomes to organize chromatin, and seized by selfish elements to survive.

Aging involves progressive declines in physiologic homeostasis, but the molecular mechanisms that in youth drive organisms away from equilibrium remain unclear. Using absolute transcript quantification, we identify a global collapse in cellular and organismal mRNA abundance that occurs in most cell types during invertebrate and mammalian aging. Using an interventional nematode model, we find that global declines in mRNA abundance are tightly coupled to global declines in RNA Polymerase II (RNAPolII) protein abundance. Longitudinal measurements reveal that individuals enter adulthood in a disequilibrium state, with nuclear RNAPolII abundance far in excess of the steady-state level supported by adult rates of protein synthesis and degradation. As a result, RNAPolII abundance falls during adulthood, progressively limiting mRNA synthesis.

We find that even transient accelerations in the fall of RNAPolII abundance produce permanent, dose-dependent reductions in healthspan and lifespan. Conversely, modulation of insulin/IGF signaling simultaneously slows declines in RNAPolII and global mRNA abundances while increasing healthspan and lifespan. Together, our results demonstrate how an out-of-equilibrium state of RNAPolII present in early adulthood is sufficient to drive organismal aging, and highlights a new molecular target for interventions aimed at preserving mRNA synthesis capacity in aging.

Neurons acquire distinct molecular identities during development through specific transcriptional programs, which must be actively maintained throughout the lifespan. Characterizing the molecular identity of fully differentiated neurons is therefore critical for understanding nervous system organization and function. This identity is encoded by the coordinated expression of neuron type–specific genes, which distinguish individual neuronal subtypes, and shared neuronal genes, which support core neuronal features and functions.

In C. elegans, the expression of shared neuronal genes is regulated by the combined action of broadly expressed CUT homeobox transcription factors and neuron type–specific master regulators known as terminal selector (TS) transcription factors. Previous studies have shown that CUT homeodomain binding motifs are strongly associated with differential chromatin accessibility between induced neurons and fibroblasts, suggesting a potential pioneer factor role for CUT proteins. We hypothesize that CUT factors modulate chromatin accessibility to facilitate the binding of additional transcription factors.

To investigate how CUT factors influence the neuronal chromatin landscape, we developed a method to isolate nuclei from all C. elegans neurons by FANS and profile chromatin accessibility in CUT homeobox mutants. This revealed reduced chromatin accessibility in the regulatory regions of shared neuronal genes, consistent with the established role of CUT factors in pan-neuronal gene regulation. Strikingly, we also identified changes at the regulatory regions of neuron type–specific genes, pointing to a broader role in neuronal identity. Revisiting bulk transcriptomic data from CUT mutants confirmed this observation: expression of both shared neuronal and neuron type–specific genes is reduced in CUT mutants. To directly characterize this broader contribution, we performed single-nucleus transcriptomic profiling of FANS-isolated nuclei from wild-type and CUT mutant animals, providing the first comprehensive view of CUT factor function at single neuronal subtype resolution.

The microbiome profoundly influences host physiology, including immune homeostasis and defense against infection, yet the molecular signals by which specific commensal bacteria modulate innate immunity remain poorly defined. The nematode Caenorhabditis elegans provides a powerful system for dissecting these host–microbiome interactions, as it possesses a simple and well-characterized innate immune system and a defined natural microbiome. One of the key immune programs in C. elegans is the Intracellular Pathogen Response (IPR), a transcriptional response activated by obligate intracellular pathogens of the intestine, including viruses and microsporidia. The IPR shares some similarities with the mammalian type I interferon response and serves as a framework for understanding how intestinal epithelial cells respond to infection. To identify microbiome members capable of modulating the IPR, we screened twelve native bacterial isolates for their ability to activate an IPR fluorescent reporter. We discovered that Stenotrophomonas indicatrix (JUb19) robustly induces reporter expression in multiple tissues, including the intestine, epidermis, neurons, and somatic gonad. Other Stenotrophomonas species trigger similar activation, suggesting a genus-linked feature. Notably, JUb19 resides extracellularly in the intestinal lumen, making this the first known example of a non-invasive bacterial species that activates the IPR reporter. Mechanistic analyses revealed that heat-killed JUb19 fails to induce IPR reporter expression, whereas mechanically or chemically inactivated bacteria retain this activity, indicating the presence of a heat-labile molecular trigger. Transcriptomic profiling revealed that JUb19 only partially induces the IPR, alongside broader metabolic remodeling. Nevertheless, this response confers resistance to both viral and microsporidian infections, and this protection is also inherited by naïve progeny that were never exposed to JUb19. We further show that bacterial RNA acts, at least in part, as a molecular cue underlying the transcriptional and immune phenotypes associated with JUb19 exposure. Together, these findings establish a new paradigm for microbiome-driven epithelial immunity in C. elegans, in which microbiome-derived RNA links bacterial exposure to immediate and intergenerational defense against intracellular pathogens.

The DREAM complex is a conserved transcriptional repressor of cell cycle genes that promotes quiescence and regulates the expression of germline genes. Using C. elegans we found that DREAM binds and represses multiple genes involved in the DNA damage response. DREAM-complex-deficient mutants show a remarkable resistance to, and improved repair of various DNA-damage types, during both development and aging. The mechanisms of DREAM complex regulation are not fully understood, but emerging evidence shows that this complex interacts with epigenetic modulators that could be driving its repressive function. Among them, the deposition of the H2A variant H2A.Z in gene bodies has been described as a DREAM-mediated repression mechanism in C. elegans.

Using a forward genetic screen in C. elegans we found that a mutation for the gene ssl-1 (ortholog of SRCAP/EP400), involved in the maintenance and deposition of H2A.Z, confers severe sensitivity to DNA damage. Employing RNA-seq and ChIP-seq analysis on these mutants we observe a broad downregulation of DREAM-associated genes, including repair genes. Repressed genes in ssl-1 mutants are characterized by a marked reduction of H2A.Z around the promoter area, suggesting that H2A.Z deposition is required for the normal expression of DNA repair genes. Furthermore, the capacity to deposit H2A.Z is also required for the DNA damage resistance phenotype of DREAM deficient organisms.

In summary, we identify a novel function for H2A.Z deposition in the regulation of DNA repair genes and DREAM target genes. Unlike previous research linking DREAM and H2A.Z, our analysis suggests that H2A.Z at the promoter region has an activating effect that is needed in both wild-type and DREAM-deficient mutants for genome maintenance.

Introduction: Spinocerebellar ataxia type 3 (SCA3), also known as Machado–Joseph disease, is a neurodegenerative disorder caused by an unstable expansion of CAG trinucleotide repeats in the ATXN3 gene. This expansion results in an abnormally long polyglutamine (PolyQ) tract within the ATXN3 protein, which promotes protein misfolding, self-association, and the formation of intracellular toxic aggregates. These aggregates are widely considered to contribute to neuronal dysfunction and degeneration. Previous studies have demonstrated that treatment with citalopram (CIT), a selective serotonin reuptake inhibitor (SSRI), can ameliorate SCA3-related pathogenesis in both Caenorhabditis elegans and mouse models [1]. CIT binds to the serotonin transporter (SERT), inhibiting serotonin (5-HT) reuptake from the synaptic cleft and thereby enhancing 5-HT signalling via serotonin receptors (5-HTRs) [1, 2]. The therapeutic effect of CIT in SCA3 is dependent on serotonin receptor activity. Recently, the LGC-50 receptor was identified in C. elegans as a pentameric cation channel activated by serotonin [3], functionally analogous to the human 5-HT3 receptor (5-HT3R), which is also a pentameric ligand-gated ion channel composed of five subunits mediating fast excitatory neurotransmission in both the central and peripheral nervous systems [4].

Aims: The present study aimed to explore the degree of homology between LGC-50 and human 5-HT3R using detailed bioinformatic analyses and to assess the functional role of LGC-50 in the pathogenesis of SCA3 using genetically modified C. elegans models. Specifically, we sought to compare the structural characteristics of LGC-50 and human 5-HT3R subunits and to evaluate the impact of modulating LGC-50 expression on mutant ATXN3 aggregation, neuronal health, and motor dysfunction in SCA3 worm models.

Methods: Bioinformatic analyses were conducted to compare the two- and three-dimensional structures of LGC-50 and human 5-HT3R subunits, using HHpred, EMBL-EBI T-Coffee and PyMOL. Genetic tools, including CRISPR–Cas9 and Mendelian breeding strategies, were employed to generate C. elegans SCA3 models with altered LGC-50 expression, including receptor deletion (LGC-50 del; AT3q130) and exclusive LGC-50 expression (LGC-50 only; AT3q130). Motor function was assessed using motility assays, and mutant ATXN3 aggregation was quantified via confocal microscopy.

Results: Sequence analysis revealed high similarity and low E-values between LGC-50 and all human 5-HT3A–E receptor subunits, except for 5-HT3D. Three-dimensional structural analyses demonstrated significant homology, particularly in the 5-HT binding domain of the 5-HT3A subunit. Deletion of LGC-50 in C. elegans expressing mutant ATXN3 did not alter disease phenotypes. Unexpectedly, expression of LGC-50 alone, in the absence of other 5-HTRs, was sufficient to suppress motor deficits and neuronal aggregation associated with mutant ATXN3. Control 5-HTR-null animals also displayed partial SCA3 suppression, a finding currently under validation in additional mutant strains.

Conclusion: These findings suggest that LGC-50 is a likely C. elegans homologue of human 5-HT3A. Moreover, LGC-50/5-HT3R may play a key role in mitigating SCA3 pathogenesis, supporting the importance of serotonergic signalling in the development and potential treatment of SCA3/Machado–Joseph disease.

The successful execution of cellular processes depends on the coordinated interactions of proteins. Consequently, imbalances in protein homeostasis (proteostasis) underlie the pathogenesis of numerous human disorders including cancer, diabetes and neurodegenerative diseases. In many of these conditions, proteostasis disruption results in the aggregation of specific proteins, which constitutes the key pathogenic event.

Over the last few years, our group has uncovered a novel, protective role of reduced glutathione (GSH) in yeast, Caenorhabditis elegans and mammalian cell models of proteotoxicity caused by aggregation-prone proteins. We have demonstrated that GSH modulates autophagy at multiple levels and that compromising GSH availability, either genetically or pharmacologically, severely impairs redox regulation of autophagy-dependent degradation of protein aggregates, ultimately leading to cellular and organismal death [1,2]. However, the type of cell death as well as the molecular mechanisms governing the lethal phenotype associated with exacerbated protein aggregation following disruption of GSH redox homeostasis remain unknown.

In this study, we will present evidence that C. elegans expressing aggregating proteins in muscle cells rapidly die upon exposure to glutathione-depleting compounds and identify ferroptosis —a recently discovered iron-dependent cell death caused by massive plasma membrane lipid peroxidation—, as the ultimate cause of death. Our findings reveal that both the reverse transsulfuration pathway and the cystine reduction pathway are required for the survival of worms expressing aggregation-prone proteins in muscle cells [3], and that inhibition of ferroptosis, but not apoptosis or necroptosis, restores animal viability. In addition, we will discuss recent proteomic and transcriptomic analyses, as well as genetic suppressors arising from a genetic screen, to further elucidate the molecular players and pathways underlying the differential responses of C. elegans tissues and organs to protein aggregation and ferroptosis.

Actin crosslinkers and myosins shape whether an actomyosin network is dynamic or stable, tuning it to the mechanical needs of the contractile structure it builds. I will discuss how crosslinker and myosin identity contribute to the assembly and function of contractile actin networks in C. elegans, drawing on work in contractile systems such as the spermatheca and the early zygote. I will close by presenting a newly funded COST Action on advancing nematode research through technology and collaboration across Europe, and invite the community to get involved.

Progerias are rare syndromes that cause accelerating ageing since early childhood, with an average lifespan close to 15 years. The aetiology lies in mutations within components of the nuclear envelope, like lamin (Hutchinson-Gilford Progeria Syndrome) and BAF (Néstor-Guillermo Progeria Syndrome). Patients suffer typical problems linked to ageing, like osteoporosis, atherosclerosis, lipodystrophy, sarcopenia, hair loss, etc. Paradoxically, it is remarkable that they do not develop neurodegeneration, a classical hallmark of ageing.

Using a C. elegans model of Néstor-Guillermo Progeria Syndrome (baf-1(G12T)), we have observed a significant resistance to polyQ-associated neurodiseases like, Huntington and Joseph-Machado ataxia. The frequency of protein aggregates is reduced specifically in neurons of baf-1(G12T) mutants, accompanied by an improvement in motility and touch response. Other neurodegenerations, as Alzheimer, Parkinson and ALS are also triggered by aggregation of aberrant proteins, that interfere with the correct physiology of the cell. Specifically, many studies suggest that the main intracellular process affected is endolysosomal trafficking, key in neurons. Interestingly, our work indicates that Néstor-Guillermo Progeria Syndrome also affect endolysosomal trafficking both in C. elegans and human patient cell lines. Analysis of chromatin accessibility in neurons reveals that the progeria mutation induces opening of genes involved in proteostasis. We postulate that accelerated-ageing disorders antagonize neurodegeneration through endolysosomal trafficking

Cell cycle regulators have long been regarded as passive elements regulating cell fate during development. Their main role is to control the timing of cell cycle phases. This is particularly true for the mitosis-to-G1 transition, which is critical for differentiation. However, whether cell cycle regulators directly influence developmental decisions beyond their canonical functions remains largely unclear. This communication shows how the Anaphase Promoting Complex/Cyclosome (APC/C)—an E3 ubiquitin ligase involved in cell cycle regulation—together with its coactivator FZR-1, can induce the acquisition of terminal features in cellular lineages across different tissues.

APC/CFZR-1 is required for the differentiation of hermaphrodite Distal Tip Cells (DTCs). Hermaphrodite DTCs arise post-embryonically following two consecutive Wnt-regulated divisions of the Z1/Z4 precursor cells in the somatic gonad primordium at the L1 stage. In this context, APC/CFZR-1 activity determines whether the descendants of the Z1.a/Z4.p cells adopt the DTC fate or the alternative Sheath and Spermatheca precursor (SS) fate. APC/CFZR-1 promotes DTC fate through proteasome-mediated downregulation of EFL-3, a transcriptional regulator that modulates the bHLH transcription factors LIN-32 and HLH-12, both required for DTC specification.

The regulatory logic identified in the somatic gonad appears to be conserved in additional developmental contexts. Other Wnt-regulated postembryonic decisions, including those within the postdeirid lineage that gives rise to the PDE and PVD neurons, were examined. Consistent with previous findings, loss of FZR-1 function compromises the establishment of PDE and PVD fates, resulting in severe motility defects. Furthermore, lin-32and efl-3 seem to interact with FZR-1 to promote neurogenesis in a manner similar to the one initially described in the somatic gonad.

Extending these findings, we will introduce high throughput motility analyses of fzr-1-deficient worms, which supports a broader role for APC/CFZR-1 as a regulator of terminal differentiation across diverse lineages in C. elegans .

Viruses, the most abundant biological entities on Earth, infect all known living organisms. If a virus produces double-stranded RNA during its life cycle it will often be recognised by the RNA interference (RNAi) pathway and the Argonaute (AGO) proteins, leading to its degradation. Orsay virus (OrV), a positive sense RNA virus, replicates in the intestinal cells of C. elegans. OrV is recognised and degraded by the RNAi machinery, and even though we have a general understanding of the players involved in the antiviral RNAi response, we still lack mechanistic details about the process. In particular, we still don’t understand how the RNAi silencing complex is organised within cells and how dynamic the complex is throughout the infection. By using a combination of live-cell imaging and FISH, we describe a dynamic localisation pattern, with primary and secondary AGO proteins localising only to bystander cells in the phase of maximum replication, and to infected cells at later timepoints, suggesting a transient viral induced repression mechanism. This was accompanied by an absence of AGO-bound viral small interfering RNAs (vsiRNAs) at early stages, whilst vsiRNAs were bound at later timepoints. Progression of viral load in different AGO mutants indicate that these proteins do not act on viral degradation at early stages, but determine the outcome of the infection. Moreover, we describe distinct somatic AGO complexes upon infection and different sub-cellular locations at different stages of infection. Proximity interaction mapping allowed us to characterise the different complexes formed, distinguishing between common and unique interactors of AGO proteins, highlighting the diverse roles of AGO proteins and identifying unexpected interactors upon infection. Collectively, these results improve our understanding of the RNAi silencing complexes induced upon viral infection, inform on antiviral intercellular communication mechanisms and highlight the complex and dynamic nature of the interactions between viruses and the RNAi pathway. 

Huntington’s disease (HD) is a rare neurodegenerative disorder caused by expanded mutant huntingtin (mHTT) aggregation. With no disease-modifying therapies currently available, symptoms include motor and cognitive decline and psychiatric alterations. However, beyond classic proteotoxicity, systemic metabolic dysfunction is increasingly recognized as a hallmark of HD. Indeed, robust lipid dysregulation has been demonstrated across various HD models and in clinical patient data (unpublished, from our group). To address this metabolic disruption, we aimed to concurrently modulate convergent energy and lipid pathways by combining the PPARγ agonist rosiglitazone (RZ) with the AMPK activator salicylate (SAL). This strategy serves as a proof-of-concept that parallel reprogramming of the lipid-energy axis can restore metabolic equilibrium and directly enhance cellular health and induce neuroprotection.

Using Caenorhabditis elegans (C. elegans) models expressing pan-neuronal 40Q::YFP or mHTT128Q::CFP prone-to-aggregation proteins, we evaluated the impact of parallel RZ/SAL co-treatment on functional outcomes and proteotoxicity. By shifting the focus to a purely metabolic perspective, we found that concurrent pathway activation significantly restored motor function, improved mechanosensory responses, and mitigated proteotoxic stress. Notably, Bliss Independence analysis confirmed true synergistic effects specifically for the reduction in the number of neuronal protein aggregates (2.43-fold above additive expectation), as well as motor rescue (3.27-fold). As an added benefit of this metabolic alignment, these protective effects were achieved using sub-effective concentrations (50 µM RZ and 5 µM SAL), entirely circumventing the need for high-dose monotherapy. Genetic loss-of-function studies demonstrated that this protection requires both AMPK (aak-2) and the PPARγ functional homolog NHR-49 (nhr-49) activation, with intestinal NHR-49 re-expression sufficient to restore efficacy.

To validate results at the subcellular level, we analysed mitochondrial bioenergetics, β-oxidation, and lipid remodelling. Quantitative lipidomics demonstrated that while pan-neuronal polyQ expression induces systemic lipid depression, parallel RZ/SAL co-treatment coordinately rewires the metabolic state. This shifts lipid flux toward cell-membrane stabilization and the adaptive synthesis of protective ultra-long-chain neutral triglycerides, which mechanistically translates into restored mitochondrial network morphology and biomass. Finally, this synergistic reduction in proteotoxicity was conserved in mammalian HEK293 cells expressing the mutant huntingtin caspase 6 fragment (mHTT121Q), confirming a maintained cross-species mechanism of action.

Overall, our findings strongly suggest that the lipid-energy axis is a fundamental, targetable regulator of cellular proteostasis. By demonstrating that parallel activation of the  PPARγ-like nuclear hormone receptor NHR-49 and AMPK pathways restores mitochondrial health and reduces aggregation, we show that actively reshaping specific lipid profiles is a primary determinant of proteotoxic resilience. This work highlights a distinct therapeutic framework for HD, moving beyond direct aggregate clearance toward an approach focused on metabolic reprogramming to preserve mitochondrial and cellular health.

Touch is essential for survival, enabling organisms to detect and respond to environmental stimuli and generate appropriate behavioral outputs. Beyond reflexive responses, mechanosensation also contributes to complex behavioral states, yet the cellular and molecular mechanisms that shape touch sensitivity remain incompletely defined. While mechanosensory neurons are known to mediate stimulus detection, they function within a microenvironment shaped by glia; however, the contribution of glia to mechanosensory processing has remained poorly understood. Here, we identify a previously unrecognized role for glial-derived serotonin in regulating touch sensitivity in Caenorhabditis elegans. Using a combination of in vivo Ca²⁺ and serotonin imaging, fluorescence microscopy, and behavioral assays, we show that Amphid Sheath (AMsh) glia release serotonin via dense-core vesicles. This release is spatially and temporally coordinated with sensory activation, supporting a direct role for glia in modulating neuronal output. Mechanistically, glial serotonin activates the neuronal SER-5 receptor to enable robust ASH neuron responses. In parallel, serotonin engages the glial MOD-1 receptor, establishing a feedback loop that fine-tunes touch perception. This dual targeting of neuronal and glial receptors supports a model in which glia both initiate and self-regulate serotonergic signaling. Extending beyond touch, we find that serotonin signaling also modulates additional ASH-mediated aversive behaviors, including responses to high osmolarity and the repellant octanol, indicating that glial serotonin broadly influences polymodal sensory circuits. We further define a concentration-dependent mechanism through which serotonin tunes sensory responsiveness. Specifically, distinct serotonin levels differentially engage cAMP- and Ca²⁺-dependent pathways, suggesting that neuromodulator concentration provides a graded means of controlling circuit output rather than a simple on/off signal. This mechanism offers a framework for understanding how glia dynamically adjust sensory gain under varying environmental conditions. Together with prior evidence for glial GABA release, these findings support a model in which glia actively regulate both mechanosensory and chemosensory function by providing complementary excitatory and inhibitory signals. In this context, glia emerge as integral components of sensory circuits that shape the amplitude and fidelity of behavioral responses. More broadly, these results raise the possibility that modulation of extracellular serotonin levels, such as by selective serotonin reuptake inhibitors (SSRIs), may influence glia-neuron signaling dynamics and thereby alter sensory processing.

A well-characterized function of non-coding RNAs (sRNAs) expressed in animal germ cells is the silencing of transposable elements by RNA interference. In this regulatory paradigm, sRNA molecules loaded into Argonaute proteins act as guides, targeting transposon RNAs through antisense complementarity and repressing their expression at both post-transcriptional and transcriptional levels, thereby preserving genome integrity and fertility. However, the vast majority of germline-expressed sRNAs do not target transposons, suggesting broader roles in endogenous gene regulation.

By studying sRNA pathways during C. elegans germline development, we found that PIWI-interacting small RNAs (piRNAs) and 26G-RNAs, two distinct classes of germline-expressed sRNAs, directly repress the transcription of hundreds of spermatogenesis-specific genes. These two pathways exhibit distinct target specificities, each regulating a largely non-overlapping set of transcripts, and together repress nearly the entire sperm-specific gene expression program. At the cellular level, this regulatory activity controls the timing of spermatogenic differentiation and is required for proper sperm function. Genetic assays reveal synthetic sterility in mutants deficient for both pathways. This phenotype is caused by the production of non-functional sperm, confirming the cooperative function of piRNAs and 26G-RNAs during spermatogenesis.

Overall, these findings reveal that transcriptional repression of spermatogenic genes is a shared function of mechanistically distinct germline sRNA pathways that together regulate endogenous gene expression programs essential for fertility.

Moderately cold temperatures extend lifespan and promote health across species, yet the molecular mechanisms underlying these benefits remain unclear. Here, we define a metabolite-driven, multi-tissue signaling system that links cold temperature to enhanced longevity and proteostasis in Caenorhabditis elegans. We find that moderate cold temperature upregulates the biopterin-synthesis enzyme GCH1/CAT-4, leading to increased production of the metabolite dihydrobiopterin (BH2) in muscle cells. Subsequently, BH2 is transported to distal tissues, including the intestine and neurons, where it is converted into its bioactive form, BH4. This enzymatic cofactor activates phenylalanine hydroxylase PAH-1, increasing tyrosine synthesis and thereby extending lifespan. Moreover, elevated BH2 levels prevent disease-related protein aggregation and subsequent neuronal dysfunction during aging. Notably, increasing BH2 synthesis in muscle cells is sufficient to promote longevity and suppress pathological protein aggregation in distal tissues, even at normal or elevated temperatures. In human cells, BH2 and tyrosine supplementation prevents aggregation of polyQ-expanded proteins associated with Huntington’s disease, as well as ALS-causing mutant variants of TDP-43 and FUS. Together, these findings identify BH2 as a central cold-induced metabolite whose synthesis, transport, and utilization preserve organism-wide proteostasis and extend lifespan.

Behavioural variation is fundamental to organism survival and reproduction, mediating key ecological interactions such as foraging, mate choice, and avoidance of predators and pathogens. Despite its importance, the mechanisms underlying behavioural variation remain poorly understood. In particular, pathogen avoidance behaviour represents a critical yet underexplored adaptive trait, with existing studies largely confined to laboratory-adapted systems and non-ecologically relevant pathogens. Consequently, the natural genetic architecture of avoidance behaviour remains largely unknown.

Here, we analysed natural variation in avoidance behaviours at the species-wide level to test whether there are genetic ‘hot spots’ for behavioural avoidance, and whether avoidance variation is pathogen specific. For this, we used world-wide natural isolates of the nematode Caenorhabditis elegans and a curated panel of naturally associated bacteria, combining quantitative behavioural approaches with a quantitative genetics framework. We quantified pre-contact (chemotaxis) and post-contact (lawn leaving) avoidance behaviours, that capture distinct sensory and behavioural processes, across 94 wild C. elegans for six bacteria: four ecologically associated pathogenic bacteria, the pathogenic Serratia marcescens (Db11), and the reference beneficial Escherichia coli strain OP50. We observed a broader natural behavioural avoidance for post-contact than for pre-contact avoidance, and, surprisingly, avoidance behaviours are not inversely correlated to bacterial virulence. Next, we performed genetic correlation analysis to test to what extent genetic variation contributes to the covariation of distinct behavioural traits. We observed an absence of genetic correlation for pre- and post-contact avoidance for a given bacterium, and for pre-contact among different bacterial strains, suggesting independent genetic basis for these traits. In contrast, our analysis reveals a shared genetic architecture for post-contact avoidance among bacterial strains by showing multiple significant positive genetic correlations. Finally, we performed genome-wide association studies (GWAS) to identify naturally segregating variants. Surprisingly, we mapped several quantitative trait loci (QTL) across the genome that were independent for post-contact avoidance among bacterial strains, and partly overlapping for pre-contact avoidance among bacterial strains and for pre- and post-contact avoidance behaviours. Interestingly, all these QTL harbour variations in genes with putative chemoreception function, representing potential candidates for future analysis.

Altogether, our results show new insights of a complex natural genetic architecture of bacterial avoidance towards ecologically associated microorganisms in C. elegans. We will discuss whether these genetic architectures of avoidance behaviours are mediated by linkage, pleiotropy, selection and/or mutational input.

Transcription factors (TFs) are the main orchestrators of gene expression. An universal feature of TFs is their pleiotropy, they are usually expressed in several cell types and tissues and their specific actions are determined by the context, mainly the combined action with other TFs and the specific chromatin landscapes of each cell type or state. Caenorhabditis elegans nervous system is composed by 118 neuron types, which are specified by combinations of TFs termed terminal selector (TS) collectives. Although at least one TS has been identified for almost every neuron type, we do not know the cell-type specific binding profiles for those TFs. In addition, a few TFs are recurrently used as TS for a broad number of different neuron types, and how they execute their different actions is now well understood. Due to their pleiotropic actions, conventional approaches, such as whole-worm chromatin immuno precipitation followed by sequencing (ChIP-seq) fail to provide cell-type specific information.

We aim to overcome these difficulties by using a combination of genetic tools to obtain C. elegans strains in which a given TF will be endogenously and specifically tagged in a given neuron type and then its chromatin binding profile will be determined by CUT&RUN. We are using CRISPR to knock in a cassette that labels global endogenous TF expression with RFP fluorescence and when combined with a strain expressing a flipase recombinase in a neuron-type specific manner, the endogenous TFs switches to TF::eGFP::3xFLAG tagging only in that specific neuron type. We have already successfully labeled and recombined different TFs with this cassette. Recombined strains will be later used to profile TF binding using anti-GFP nanobodies and CUT&RUN. We are currently establishing this methodology to profile different TFs that act as TS of specific neuron types and gain insights in their mode of action.

Robust development requires the precise temporal coordination of parallel biological processes, yet how multicellular organisms detect and correct timing mismatches between developmental events remains poorly understood. During Caenorhabditis elegans postembryonic development, larval molts and stage-specific cell divisions proceed in parallel and are influenced by environmental cues such as nutrient availability. Although these processes often appear tightly synchronized, their underlying timers are mechanistically distinct, raising the question of how temporal coherence is maintained.

We have identified a previously unrecognized and highly variable pause at the beginning of larval stages revealed by continuous single-animal luminometry. This lag, which we term L2lag, occurs immediately after ecdysis and before the onset of the next intermolt and is strongly enhanced under reduced insulin signaling in daf-2 mutants. Importantly, L2lag is not a trivial consequence of slow development: its duration is largely uncorrelated with that of other larval stages and persists even when canonical insulin-dependent developmental delays are genetically suppressed.

By combining high-resolution time-lapse microscopy reporting molting and seam cell divisions in the same animal, we show that L2lag arises from a desynchrony between the timing of cell divisions and ecdysis. Reduced insulin signaling delays seam cell divisions more strongly than ecdysis, creating a mismatch. Larvae entering L2lag display incomplete seam cell divisions, and experimentally advancing or delaying divisions relative to ecdysis respectively shortens or prolongs the lag. These findings demonstrate that L2lag reflects a compensatory delay triggered by unfinished stage-specific cellular events.

Together, our results suggest a checkpoint-like mechanism at larval stage boundaries that prevents the propagation of timing errors across development by delaying the initiation of the next stage until key events are complete. This work reveals how developmental timing remains robust despite variability and perturbations, and positions C. elegans larval transitions as a powerful system to dissect the principles of temporal coordination in development.

The conserved mitochondrial prohibitin (PHB) complex is crucial for maintaining mitochondrial homeostasis. However, its depletion produces an opposing effect on lifespan, shortening it in wild-type C. elegans while extending it in insulin/IGF-1 receptor daf-2 mutants. This differential outcome is associated with a blunted mitochondrial unfolded protein response (UPR^mt) in long-lived mutants. In order to identify regulators underlying this context-dependent stress response and lifespan modulation, we performed the first genome-wide double RNAi screen in C. elegans. We identify the ubiquitin-specific peptidase USP-48 as a novel modulator of the UPR^mt, which is especially required for longevity under reduced insulin signalling. Transcriptome analysis reveals that daf-2 and usp-48 mutants share a large number of differentially expressed genes, suggesting a functional overlap. USP-48 regulates mitochondrial structure and function and interacts with the transcription factor DVE-1 to regulate the UPR^mt largely independently of ATFS-1. Mechanistically, our data suggests that USP-48 acts through histone H2B deubiquitination to influence stress-responsive gene expression. Our findings demonstrate the utility of double RNAi genetic screens for essential genes and highlight ubiquitination as a new epigenetic determinant of metabolism-mediated longevity.

Caenorhabditis elegans (C. elegans) is a valuable preclinical model for evaluating the health benefits of probiotics (live strains) and postbiotics (heat-inactivated strains) due to its genomic similarity to mammals and ease of cultivation. ADM® utilizes this model in its research to support the incorporation of functional postbiotics into food applications for both humans and animals. The inherent stability and safety of postbiotics can help to maintain product quality and shelf life, while preserving taste and texture.

This study aimed to validate the functionality and stability of heat-inactivated microbial strains in final food and feed formulations using the C. elegans model. Two recently commercialized heat-inactivated strains from ADM® were evaluated: PRIOME® Joint Health (Lacticaseibacillus rhamnosus), developed to support canine joint health, and Lactobacillus gasseri CP2305, which has been shown to promote mental well-being and sleep quality in humans.

To conduct this study, both heat-inactivated strains were exposed to industry-relevant conditions specific to their intended food applications, including high temperature, high pressure, pH variations, Brix levels and food preservatives. After these treatments, samples were stored at room temperature for 12 months (the products’ expected shelf life). In addition, postbiotics were incorporated into their respective food matrices—such as extruded dry kibbles as pet food for heat-inactivated PRIOME® Joint Health and in gummies, chocolate and cereal bars as food products for heat-inactivated L. gasseri CP2305 and tested. The postbiotic-containing food matrices were then subjected to the relevant industrial processing conditions and subsequently stored at room temperature for 4 months (dry kibbles) or 12 months (gummies, chocolate and cereal bars). C. elegans were fed with the corresponding samples containing postbiotics to evaluate their respective functionality; PRIOME® Joint Health was assessed for its capacity to reduce fat accumulation in the nematode, as obesity is a well-established contributor to the degeneration of joint structures. The heat-inactivated L. gasseri CP2305 was tested for its antioxidant effect by measuring worms’ survival following induction of acute oxidative stress (with hydrogen peroxide), since attenuation of oxidative stress is known to exert beneficial effects on sleep quality.

Results indicate that the functionality of the heat-inactivated strains was preserved after exposure to the different industry conditions at time 0 and remained stable for up 12 months of storage, compared with the corresponding heat-inactivated strains not subjected to industrial processing condition (not significant differences between conditions). Moreover, these functional properties were preserved when incorporated into the specific final food applications at time 0, with functionality remaining stable after 4 months for the heat-inactivated PRIOME® Joint Health and after 12 months for the heat-inactivated L. gasseri CP2305 (not significant differences in comparison to heat-inactivated strains not included in the food matrix).

In conclusion, C. elegans is a suitable model for evaluating the functionality and stability of food applications containing heat-inactivated strains. Moreover, this study demonstrated that both heat-inactivated strains retained the functional properties evaluated, supporting their potential for incorporation into a variety of final food applications.

MicroRNAs, together with their Argonaute partner proteins, exert post-transcriptional regulation of gene expression via complementary base pairing between the microRNA and mRNAs. Genes that encode microRNAs function as negative regulators of hundreds of other genes, primarily by inhibiting the translation and/or stability of target mRNAs. MicroRNAs exhibit remarkably versatile regulatory roles within genetic regulatory networks (GRNs) – for example, to coordinate multigene functional modules, dampen gene expression noise, and/or conduct developmental switches. Genetic analysis of model organisms reveals that the function of microRNAs can be conditional – wherein a microRNA gene is required under certain environmental or physiological conditions, but relatively dispensable under other conditions. It is not uncommon for microRNA loss-of-function mutants to display emergent developmental or physiological defects when subjected to biological stresses and challenges that fall within the normal range of experience of the animal. These include temperature fluctuations within the animal’s thermotolerant range, exposure to pathogens or toxins endemic to the animal’s normal environment, or routine regeneration of tissues after injury. The observation that microRNA genes exhibit stress-dependent conditional phenotypes is interpreted to suggest prominent roles for microRNAs in enabling developmental and homeostatic processes to weather the contingencies of everyday life.

Brains process information in a very plastic manner so that animals never respond to an identical stimulus in the same way twice. This is the basis of learning and decision-making, and what enables animals to respond to their environment according to their ever-changing needs. In the Barrios lab we investigate the mechanisms that provide brains with this flexibility in function. I will present our work on how previous experiences, internal state, and biological sex shape neural circuit function and behaviour to meet animal needs. We use a combination of genetics, molecular biology, neuronal recordings and behavioural analysis.

Horizontal transfer of transposable elements (HTT) is increasingly recognized as an important force shaping animal genome evolution, yet the ecological and molecular factors promoting these events remain poorly understood. Our previous discovery that Maverick transposons can capture host genes and transfer them between distantly related nematode species provided evidence that virus-like transposable elements can act as vectors of horizontal gene transfer in animals. Building on this finding, we sought to determine how widespread recent HTT is across nematodes and to identify the evolutionary, ecological, and molecular factors associated with these transfers.

We performed a large-scale analysis of recent HTT across 198 nematode species with available whole-genome sequences. Using a conservative comparative genomic approach focused on protein-coding transposable elements, we identified 1,389 high-confidence HTT events involving 134 species, demonstrating that recent horizontal transfer is widespread across the phylum Nematoda. HTT was strongly influenced by phylogenetic distance, with closely related species displaying higher transfer rates. Ecological similarity also played a major role: most transfers occurred between species sharing the same lifestyle, either free-living or parasitic, whereas transfers between species with different lifestyles or host types were rare.

Notably, approximately 60% of all HTT events involved just three transposable-element families: DNA-Maverick, LTR-Pao, and LTR-Gypsy. These families encode viral-like proteins, including capsid-like and fusogen-like or envelope proteins, suggesting that their ability to form viral-like particles may facilitate transmission between species. Together, our findings establish nematodes as a powerful system for investigating the mechanisms and evolutionary consequences of HTT in animals and support a prominent role for transposable elements with viral properties in mediating gene flow across species boundaries.

Genetic variants in genes involved in rare diseases are understudied because their low prevalence leads to insufficient support from funding agencies and the pharmaceutical industry. Menkes Disease (MD) is a rare multisystemic disease caused by mutations in the ATP7A gene that result in the inability to distribute the copper absorbed in the intestine throughout the organism. This X-linked genetic disorder has an incidence of around 1 in 300.000 male births, with a life expectancy of less than 3 years. Other mutations in ATP7A can also cause milder diseases like Atypical Menkes Disease (AMD), Occipital-Horn Syndrome (OHS), or X-linked distal Spinal Muscular Atrophy type 3 (SMAX3). Interestingly, mutations in ATP7B, a paralog of ATP7A sharing ~65% sequence identity, can cause Wilson Disease (WD), another rare copper-related disease due to copper accumulation and toxicity, primarily affecting the liver and brain.

In Caenorhabditis elegans, cua-1 is the common ancestral ortholog gene for human ATP7A and ATP7B copper-transporting P-type ATPases, with a similarity of 45% in the protein sequence. Notably, many of the key amino acids involved in the diseases are conserved in C. elegans. Using CRISPR-Cas genome editing, we have mimicked several ATP7A and ATP7B missense mutations in cua-1, allowing the modelling of at least five distinct diseases using a single gene. Mutations in cua-1 produce a spectrum of phenotypes, ranging from severe larval lethality to reduced brood size. Interestingly, the penetrance of these phenotypes can be modulated by regulating copper bioavailability. Additionally, we show that Elesclomol, a drug in a clinical trial to treat Menkes Disease, partially rescues the most severe phenotypes in our models. Together, we are implementing C. elegans as a rapid and accurate model for functional studies of ATP7A and ATP7B variants to exploit it in clinical diagnosis and drug screens for different copper-related rare diseases.

The fog-2 (Feminization Of Germline) gene is involved in Caenorhabditis elegans reproductive development as a key regulator of sperm production in the L4 hermaphrodite germline. Loss-of-function mutants of fog-2 display a gonochoric phenotype, with XX animals (females) producing only oocytes and XO animals (males) producing only sperm. Interestingly, FOG-2 has been shown to have a role in immunity with fog-2 mutants being more resistant to bacterial infection. Orsay virus (OrV), a natural viral pathogen of C. elegans, is a positive sense single-stranded RNA virus related to the Nodaviridae family. It infects C. elegans through the oro-fecal route with viral replication occurring in the intestinal epithelial cells and usually being limited to just one cell per animal. To test whether the observed role of FOG-2 in immunity extends to other immune pathways, we tested its role in OrV infection. We quantified viral load of mutant animals, and show that FOG-2 is necessary to mount an efficient antiviral response and to ultimately clear infection. This mechanism was sex independent, specific to the germline spermatogenesis pathway, and not a general feature of gonochorism in C. elegans. It was accompanied by a multi-cellular infection phenotype. In rare cases, fog-2 animals showed signs of possible OrV infection in tissues other than the intestine. Consequently, OrV displayed significantly increased virulence in fog-2 mutants in general, however, the effect was stronger in females than males. We also performed a transcriptomic analysis at early, intermediate and late infection timepoints, which revealed differences in the host response to OrV infection and its change through time between wild-type and fog-2 mutant animals. Together, these results demonstrate that FOG-2, and other genes involved in reproductive development are necessary for antiviral immunity with mutant animals displaying a phenotype similar to mutants of key immunity genes, such as drh-1, pointing to broader interactions between the immune and reproductive systems necessary for their proper functioning.

The increasing development of nanomaterials for biomedical, environmental, and food-related applications requires efficient and physiologically relevant models for safety and functionality assessment. Owing to its transparent body, short life cycle, low maintenance costs, and significant genetic homology with humans, the nematode Caenorhabditis elegans serves as a powerful in vivo model. By focusing on its well described physiology, we have used as a subject in toxicological studies for a variety of potential stressors, ranging from electromagnetic radiation to plastic nanoparticles.  We have also further expanded upon traditional methods of experimentation, which are widely spread and successful, but can be enhanced with the recent advent of high-throughput technologies. Here, we also present an integrated platform based on C. elegans and the SydLab ONE^™ microfluidic screening system, which we have used for the assessment of materials at the bio–nano interface.

We exposed wild-type (N2) and cuticule-sensitive (CB6055) worms to continuous electromagnetic field radiation (RF-EMF). To mimic Wi-Fi exposure in humans, the exposure was set at 26.5 GHz, maintaining a specific absorption rate (SAR) of 1 W/kg, adapted to worm size and volume. We compared various organismal health endpoints, between exposed and non-exposed worms across two generations, and our findings reported a notable absence of effects due to RF-EMF exposure in parameters such as survival, egg hatching, length, motility, and reproductive toxicity (Figure 1A, 1B, 1C, 1D, 1E). Further studies, at the cellular level, observed oxidative damage by assessing the antioxidant capacity of exposed worms, which was not determined to be depleted by ROS production. Lastly, delving deeper into the genetic expression, functional enrichment analysis of exposed worms failed to show activation of stress-response genetic pathways that could indicate detrimental effects.

Switching focus to the potential of high-throughput technology to assess nanoparticle toxicity, the SydLab ONE^™ device enables automated, high-content screening of up to 64 experimental conditions in a single run. Combined with real-time data acquisition and AI-driven image analysis, the system allows rapid and quantitative assessment of growth, survival, motility, reproduction, and stress-related endpoints, while also significantly increasing throughput and reproducibility compared with conventional assays.

This approach provided a framework for assessing emerging contaminants prevalent in our diets, such as nanoplastics, which have been linked to oxidative stress, neurotoxicity, reproductive impairment, and metabolic dysregulation. Polylactic acid (PLA) and polytetrafluoroethylene (PTFE) nanoparticles of varying sizes and concentrations have been used to study overall organismal health. While initial studies were not indicative of any effects caused by nanoplastic exposure, further work still needs to be performed.

The platform was also applied to evaluate other plastics, such as polylactic-co-glycolic acid (PLGA) nanocapsules, in trial for their potential in drug-delivery. These were assessed for their biocompatibility with N2 C. elegans larvae during the developmental stages. The worms were exposed at 0.75, 0.5 and 0.25 mg/ml for 120 hours, with no significant alterations identified in their survival or development at any of the aforementioned concentrations, demonstrating favorable biocompatibility.

Overall, by integrating advanced microfluidics, automated data-collection, and a versatile biological model, this approach establishes a scalable and cost-effective strategy for accelerating nanomaterial safety assessment and the development of next-generation health-related nanotechnologies.

Mitochondrial dysfunction is a hallmark of aging, yet mild mitochondrial stress can promote longevity through hormetic mechanisms [1]. Here, we investigated the role of respiratory chain complex-I inhibition in aging using Caenorhabditis elegans. We found that low dose of rotenone (1 µM) significantly promoted healthy longevity. Genetic analyses indicated that this effect is at least partially dependent on complex-I function, as rotenone-induced longevity was partially abolished in nuo-6 mutants (MQ1333 strain). To explore the mechanisms underlying this phenotype, we first evaluated whether low-dose rotenone engages caloric restriction-related pathways. Although 1 µM rotenone significantly reduced both basal and maximal respiration, it did not alter AMPK or mTOR signaling activity. Nevertheless, rotenone-treated worms displayed a significant reduction in body size, suggesting metabolic adaptation independent of canonical nutrient-sensing pathways. Ongoing studies are assessing the effect of rotenone in AMPK-deficient worms and under caloric restriction conditions. We also examined whether rotenone-induced longevity is associated with activation of proteostatic stress responses. Using fluorescent reporter strains for endoplasmic reticulum, mitochondrial, and cytosolic unfolded protein responses (UPR), including SJ4005 (hsp-4::GFP), GL347 (hsp-6p::GFP), and TJ375 (hsp-16.2p::GFP), we observed that rotenone consistently activated the mitochondrial UPR at both day 1 and day 5 of treatment. Interestingly, rotenone selectively induced the cytosolic stress response in a restricted subset of pharyngeal muscle cells located in the terminal bulb, identified as pm7 cells. Together, our findings support the idea that mild complex-I inhibition promotes longevity through adaptive mitochondrial stress signaling rather than through canonical caloric restriction pathways.

Aging is a natural process characterized by the progressive development of physical, psychological, and behavioral changes over time. This process is influenced by multiple factors, including genetic, environmental, social and behavioral components, which interact in a complex manner. From a genetic perspective, research has focused on elucidating the role of specific molecular pathways and genes involved in regulating aging.

The RAS/RAF/MEK/ERK signaling pathway is an evolutionarily conserved cascade that regulates key cellular processes in metazoans, including proliferation, development, metabolism and differentiation. Mutations in this pathway are well known drivers of cancer initiation and progression; however, it is also implicated in several hallmarks of aging, such as dysregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and chronic inflammation.

In C. elegans, evolutionarily conserved RAS–ERK signaling components were originally identified through EMS genetic screens affecting vulval cell fate determination, including ksr-1 and soc-2. In addition, regulation of MPK-1 (ERK) has been extensively studied, particularly in the germline, where it controls processes such as mitotic proliferation and apoptosis. This pathway has also been linked to proteostasis, immunity, and lifespan regulation, highlighting parallels with aging-related processes described in mammals.

In mammals, null mutations in core components of the RAS–ERK pathway are embryonic lethal. Thus, conditional or inducible knockout models are required to investigate tissue-specific or systemic functions. In the case of SHOC2, a conserved positive modulator of RAS–RAF signal transduction, complete loss of function results in embryonic lethality.

Therefore, to characterize the specific aging processes regulated by SHOC2, we turned to C. elegans, where this scaffold protein was originally identified, null mutants remain viable and aging research is well established.

So far, we have observed that soc-2 knockdown shortens lifespan, alters a proteostasis aggregation reporter and induces mitochondrial dysfunction. These phenotypes are associated with gene expression changes affecting pathways such as the unfolded protein response (UPR) and extracellular matrix components, including structural collagens.

On the other hand, we are also analyzing phenotypes of a truncated mutant (n1774 allele), which may represent a partial loss-of-function allele, and those of a null mutant (tm5133 allele). soc-2 mutants exhibit decreased body size and aged-associated motility decline, upregulation of stress markers and reduced brood size and lifespan.

Cohesin is an essential component of mitotic and meiotic chromosomes due to its ability to control the topology of DNA. During the mitotic cell cycle, cohesin has essential roles in chromosome segregation by providing sister chromatid cohesion (SCC), in DNA damage repair, and in gene regulation by controlling 3D genome organization.  The core cohesin complex includes two structural maintenance of chromosome proteins plus a kleisin that recruits additional subunits that regulate the binding and activity of cohesin on DNA, including the HAWKS (Heat repeat proteins Associated With Kleisin) proteins SCC-2, SCC-3 and PDS5. During meiosis, chromosomes undergo large structural changes driven by cohesin that are required to ensure the accurate formation of haploid gametes from diploid germ cells. These changes include the formation of axial elements that promote pairing and recombination between homologous chromosomes, leading to the formation of crossover events, which together with SCC, ensure correct chromosome orientation on the first meiotic spindle. The successful execution of these events requires the assembly during early meiosis of chromosomes containing cohesin complexes with meiosis-specific kleisins: REC8 and RAD21L in mammals and REC-8 and COH-3/4 in C. elegans. Work from our group and others shows that REC-8 complexes provide SCC and contribute to axial assembly, whereas COH-3/4 complexes promote axis assembly and higher-order chromosome organisation. However, how kleisin identity determines the function of cohesin complexes during meiosis remains unclear. We are combining functional in vivo studies exploiting the advantages of the C. elegans germline with biochemical and single molecule imaging approaches to uncover the molecular mechanisms by which variant cohesin complexes control the structure and function of meiotic chromosomes. Our work sheds light on how variant cohesin complexes control meiotic chromosome organization to ensure fertility.

The Integrator complex is a conserved multi-protein assembly that binds to RNA polymerase II and regulates its activity in two different scenarios. On the one hand, it processes small nuclear RNAs (snRNAs), which are essential for the splicing of messenger RNAs (mRNAs). On the other hand, it regulates the expression of certain genes in response to specific growth factors. Mutations in the Integrator complex correlate with the appearance of tumors in various tissues. Our group has characterized the complete interactome of the Integrator complex in C. elegans, revealing unexpected functions, such as the regulation of mitochondrial activity and the response to DNA damage. These findings contribute to a better understanding of the evolutionary conservation and functional diversity of gene regulatory mechanisms in eukaryotes. Our results define a homeostatic feedback loop in which Integrator promotes mitochondrial activity, while mitochondria-derived signals modulate the Insulin/IGF-1 signaling (IIS) pathway to tune the cellular transcriptome. These findings expand the functional repertoire of the Integrator complex beyond the nucleus and establish it as a critical node in the coordination of nuclear gene expression and mitochondrial metabolism.

The intestinal microbiota modulates many aspects of human physiology, including brain function. Recently, correlations have been described between microbiota composition and certain neurodegenerative diseases (e.g., Alzheimer’s and Parkinson’s). A hallmark of these diseases is the aggregation of amyloid proteins. Amyloid aggregates self-propagate by converting soluble molecules of the same protein into the aggregated state through protein–protein interactions (self-nucleation). However, what triggers this aggregation cascade remains unknown. Since different members of the microbiota produce functional amyloids, it has been proposed that these may initiate the aggregation of human amyloids through in vivo cross-seeding, thereby causing disease. Supporting this idea, bacterial amyloids such as curli from E. coli, FapC from Pseudomonas, and amyloid sequences from BAP proteins of S. aureus increase the aggregation of human amyloids in animal models of neurodegeneration. Moreover, it has recently been shown in C. elegans that intestinal curli can reach neurons to mediate this effect.

However, it remains unknown: (i) whether in vivo cross-seeding (protein–protein interaction) between bacterial and human amyloids is the underlying mechanism driving this increased aggregation (studies investigating in vivo cross-seeding rely on fluorescence colocalization, but colocalization does not necessarily imply interaction); (ii) whether such interactions are what initiate human amyloid aggregation; (iii) whether other bacterial amyloids also reach neurons to modulate human amyloid aggregation; and (iv) whether this occurs in a protein-specific manner to promote particular diseases.

To address these questions, we are developing a bimolecular fluorescence complementation (BiFC)-based system in C. elegans to determine if, when, and where direct interactions between different human and bacterial amyloids occur, using a combinatorial approach that will allow us to uncover the protein–protein specificity of these interactions. Using this approach, we have tested the interaction between ingested CsgA and neuronal a−syn. Using fluorescence microscopy we detected reconstituted Venus fluorescence in neurons of 71% (8 days adult) transgenic C. elegans producing a−syn-CtVenus (N2, Ex[a−syn-CtVenus; rol-6]) fed with E. coli BW25113 DcsgA producing CsgA- NtVenus. Importantly, Venus fluorescence was not detected in C. elegans producing a−syn-CtVenus fed with E. coli BW25113 DcsgA or WT worms fed with E. coli BW25113 DcsgA producing CsgA-NVenus. Remarkably, despite a-syn is expressed pan-neuronally, we only observed reconstituted Venus signal in a small number of neurons. Together, our results demonstrate that cross-seeding of gut bacterial and neuronal host amyloids do occur in vivo and suggests that CsgA-a-syn interactions may only occur in specific neurons that we are currently characterising.

Another open question in the field is whether CsgA alone can be neurotoxic once it reaches the nervous system. To address this question, we generated a transgenic C. elegans expressing panneuronally an optogenetic switch that allows light-induced oligomerization of CsgA in neurons and we performed survival assays under light and dark conditions. Preliminary results suggest internal hatching in CsgA-CRY-mCherry animals exposed to light. These findings could indicate neurotoxicity, particularly affecting neurons controlling egg-laying behaviour, which we are currently investigating.

Animals must adapt to fluctuations in nutrient availability through mechanisms that coordinate survival and developmental recovery. In Caenorhabditis elegans, newly hatched larvae can survive prolonged starvation by entering L1 arrest, providing a valuable model for studying communication mechanisms under nutrient-deprived conditions [1] [2].

Here, we investigated whether sulfated steroid hormones function as extracellular signals during L1 arrest. Previous observations revealed that recovery after L1 arrest is influenced by larval density. We observed that mutants with altered levels of sulfated steroid hormones [3] appear to exhibit distinct recovery capacities. We therefore explored the potential role of sulfated C19 androgen steroid hormones in mediating adaptive responses to starvation and developmental recovery.

Our findings support a previously unrecognized role for sulfated steroid hormones in the regulation of starvation-associated responses. These molecules may act as inter-individual chemical cues that contribute to the coordination of physiological and developmental adaptations to nutrient deprivation in this organism.

Ageing is not only driven by cell-autonomous decline but also by how stress signals are coordinated across tissues. Mitochondria are central to this process, yet whether specific neuronal populations actively instruct organismal adaptation—and how glia interpret these signals—remains unresolved.

Here, we identify a neuron subtype-specific signalling axis that propagates mitochondrial stress systemically and rewires ageing trajectories in Caenorhabditis elegans. Disrupting mitochondrial prohibitins (PHB-1/2) in neurons is sufficient to trigger a robust organism-wide mitochondrial stress response, with strong activation in distal tissues such as the intestine. However, this signalling is not uniform: its strength depends on neuronal identity, with cholinergic and serotonergic neurons acting as dominant drivers of systemic UPRmt activation.

Strikingly, this inter-tissue communication is not intrinsic but conditional. While neuronal mitochondrial stress induces a sustained systemic response during ageing at 20°C, this signalling collapses under thermal stress. This switch-like behaviour predicts organismal outcomes: conditions that support sustained signalling promote longevity, whereas its failure correlates with reduced lifespan. These results argue that ageing trajectories are not simply dictated by mitochondrial dysfunction per se, but by the ability to propagate and maintain stress signals across tissues.

At the molecular level, neuronal mitochondrial perturbation does not accelerate canonical ageing but instead diverts it into an alternative trajectory. Quantitative proteomics reveals selective engagement of stress-response, immune, and trafficking pathways, alongside repression of mitochondrial and RNA-processing functions, indicating a systemic reprogramming of proteostasis networks.

Unexpectedly, glial cells do not mount a canonical UPRmt despite receiving neuronal stress signals. Instead, we observe nuclear accumulation of the stress-responsive transcription factor DVE-1 in a subset of glia, revealing a non-canonical response that is uncoupled from classical reporters. This suggests that glia act as selective interpreters of neuronal mitochondrial stress, potentially gating its propagation or transformation into downstream signals.

Functionally, mitochondrial perturbation impacts specific neuronal circuits and induces structural remodelling in glia, supporting a coordinated but cell-type-specific response to stress. Moreover, neuronal mitochondrial dysfunction differentially modulates proteotoxicity, alleviating aggregation in α-synuclein models and extending survival in an ALS model, while leaving other proteotoxic paradigms unaffected.

Together, these findings support a model in which neuronal mitochondrial stress is not merely a local defect but a regulated signal whose propagation depends on neuronal identity, environmental context, and glial interpretation. This framework positions neuron–glia communication as a key determinant of systemic ageing and proteostasis.

Introduction: The incidence of anisakiasis, a parasitic disease caused by Anisakis simplex following the consumption of raw or undercooked fish, has increased considerably in recent years. Given the limited efficacy of currently available treatments, the identification of new anthelmintic agents remains a priority. In this context, Acmella oleracea (L.) R.K. Jansen is of particular interest, as it is traditionally used to treat intestinal parasitic infections in humans and animals. However, its potential nematicidal activity and underlying mechanism of action remain poorly understood.

Methods: The nematicidal activity of a N-alkylamide-enriched supercritical CO₂ extract of A. oleracea was evaluated against Anisakis simplex L3 larvae. To investigate its possible mechanism of action, the effects on survival were assessed in Caenorhabditis elegans wild-type N2 worms and in the drug-resistant strains CB193 (levamisole-resistant) and JD608 (ivermectin-resistant) by using the WMicroTracker One system. In addition, effects on cuticle permeability and intestinal barrier integrity were also examined in N2 worms, and the in vitro acetylcholinesterase inhibitory activity of the extract was determined.

Results: The extract exhibited nematicidal activity against A. simplex after 48 h of exposure over the concentration range of 31.25 to 1000 μg/mL(IC₅₀ 130 ± 30 μg/mL). In C. elegans, the highest concentrations tested (1000–500 μg/mL) markedly reduced worm viability in N2 strain (IC₅₀ 489 ± 106 μg/mL), while the drug-resistant strains showed even more susceptibility, IC₅₀ 133 ± 38 μg/mL  and 257 ± 43 μg/mL for JD608 respectively, which suggests that the extract does noy share the targets of levamisole and ivermectin. Moreover, treatment was associated with a trend toward increased cuticle permeability and impaired intestinal barrier integrity, while no in vitro acetylcholinesterase inhibitory activity was detected.

Conclusions: A. oleracea extract showed nematicidal activity against A. simplex and C. elegans. The results suggest a mode of action distinct from those of levamisole and ivermectin, possibly involving membrane disruption. These findings support the use of C. elegans as a surrogate model for mechanistic studies in Anisakis and highlight A. oleracea as a promising source of alternative anthelmintic compounds.

Alzheimer’s disease (AD) is the most common neurodegenerative disorder and the leading cause of dementia worldwide, affecting more than 55 million people. Despite extensive research efforts, effective preventive and therapeutic strategies remain limited. In recent years, increasing evidence has highlighted the role of the gut–brain axis in neurodegeneration, revealing that gut microbiota composition and activity can influence neuroinflammation, oxidative stress, and amyloid-β (Aβ) pathology. In this context, probiotics and postbiotics have emerged as promising functional ingredients with potential neuroprotective properties. However, the identification of microbial candidates requires robust, rapid, and cost-effective screening platforms. In this context, the nematode Caenorhabditis elegans represents a valuable in vivo model for studying AD-related processes due to its short lifespan, well-characterized genetics, and the availability of transgenic strains expressing human Aβ peptides. 

The hypothesis of this work is that functional ingredients based on probiotics and/or postbiotics can exert neuroprotective effects that contribute to the prevention of AD, and these effects can be effectively evaluated using C. elegans. Therefore, the objective of this study is to develop and validate a screening platform based on C. elegans for the identification and selection of postbiotic candidates with potential neuroprotective activity. 

To achieve this goal, novel methodologies were developed and optimized using the transgenic AD strains CL4176 and CL2355. The established assays evaluated key AD-related phenotypes, including paralysis, Aβ aggregation, chemotaxis, reactive oxygen species (ROS) levels, motility, and survival. Several compounds previously described as neuroprotective agents, including epicatechin, resveratrol, caffeic acid, and sodium butyrate, were used to validate the methods and to select the most suitable positive controls for each endpoint.  

The results obtained demonstrated successful optimization and validation of the screening assays. Among the compounds tested, epicatechin and caffeic acid showed the most consistent and robust neuroprotective effects, supporting their selection as positive controls. These findings confirm the reliability of the platform, which is now ready for the evaluation of bacterial-derived functional ingredients.