RÉSUMÉ
4-Nitrophenol (4-NP), as a toxic and refractory pollutant, has generated significant concern due to its adverse effects. However, the potential toxic effects and mechanism remained unclear. In this study, the reproduction, development, locomotion and reactive oxygen species (ROS) production of Caenorhabditis elegans were investigated to evaluate the 4-NP toxicity. We used metabolomics to assess the potential damage mechanisms. The role of metabolites in mediating the relationship between 4-NP and phenotypes was examined by correlation and mediation analysis. 4-NP (8 ng/L and 8 µg/L) caused significant reduction of brood size, ovulation rate, total germ cells numbers, head thrashes and body bends, and an increase in ROS. However, the oosperm numbers in uterus, body length and body width were decreased in 8 µg/L. Moreover, 36 differential metabolites were enriched in the significant metabolic pathways, including lysine biosynthesis, ß-alanine metabolism, tryptophan metabolism, pentose phosphate pathway, pentose and glucuronate interconversions, amino sugar and nucleotide sugar metabolism, starch and sucrose metabolism, galactose metabolism, propanoate metabolism, glycerolipid metabolism, and estrogen signaling pathway. The mechanism of 4-NP toxicity was that oxidative stress caused by the perturbation of amino acid, which had effects on energy metabolism through disturbing carbohydrate and lipid metabolism, and finally affected the estrogen signaling pathway to exert toxic effects. Moreover, correlation and mediation analysis showed glycerol-3P, glucosamine-6P, glucosamine-1P, UDP-galactose, L-aspartic acid, and uracil were potential markers for the reproduction and glucose-1,6P2 for developmental toxicity. The results provided insight into the pathways involved in the toxic effects caused by 4-NP and developed potential biomarkers to evaluate 4-NP toxicity.
Sujet(s)
Caenorhabditis elegans , Oestrogènes , Nitrophénols , Reproduction , Transduction du signal , Animaux , Caenorhabditis elegans/effets des médicaments et des substances chimiques , Caenorhabditis elegans/physiologie , Reproduction/effets des médicaments et des substances chimiques , Transduction du signal/effets des médicaments et des substances chimiques , Nitrophénols/toxicité , Oestrogènes/toxicité , Espèces réactives de l'oxygène/métabolisme , Stress oxydatif/effets des médicaments et des substances chimiquesRÉSUMÉ
Cisplatin-induced nephrotoxicity restricts its clinical use against solid tumors. The present study elucidated the pharmacological effects of Renogrit, a plant-derived prescription medicine, using cisplatin-induced human renal proximal tubular (HK-2) cells and Caenorhabditis elegans. Quantification of phytochemicals in Renogrit was performed on HPTLC and UHPLC platforms. Renogrit was assessed in vitro in HK-2 cells post-exposure to clinically relevant concentration of cisplatin. It was observed that renoprotective properties of Renogrit against cisplatin-induced injury stem from its ability to regulate renal injury markers (KIM-1, NAG levels; NGAL mRNA expression), redox imbalance (ROS generation; GST levels), and mitochondrial dysfunction (mitochondrial membrane potential; SKN-1, HSP-60 expression). Renogrit was also found to modulate apoptosis (EGL-1 mRNA expression; protein levels of p-ERK, p-JNK, p-p38, c-PARP1), necroptosis (intracellular calcium accumulation; RIPK1, RIPK3, MLKL mRNA expression), mitophagy (lysosome population; mRNA expression of PINK1, PDR1; protein levels of p-PINK1, LC3B), and inflammation (IL-1ß activity; protein levels of LXR-α). More importantly, Renogrit treatment did not hamper normal anti-proliferative effects of cisplatin as observed from cytotoxicity analysis on MCF-7, A549, SiHa, and T24 human cancer cells. Taken together, Renogrit could be a potential clinical candidate to mitigate cisplatin-induced nephrotoxicity without compromising the anti-neoplastic properties of cisplatin.
Sujet(s)
Apoptose , Caenorhabditis elegans , Cisplatine , Mitophagie , Cisplatine/effets indésirables , Cisplatine/toxicité , Animaux , Humains , Mitophagie/effets des médicaments et des substances chimiques , Caenorhabditis elegans/effets des médicaments et des substances chimiques , Caenorhabditis elegans/métabolisme , Apoptose/effets des médicaments et des substances chimiques , Lignée cellulaire , Extraits de plantes/pharmacologie , Tubules rénaux/effets des médicaments et des substances chimiques , Tubules rénaux/métabolisme , Tubules rénaux/anatomopathologie , Antinéoplasiques/pharmacologie , Antinéoplasiques/toxicité , Antinéoplasiques/effets indésirables , Tubules contournés proximaux/effets des médicaments et des substances chimiques , Tubules contournés proximaux/métabolisme , Tubules contournés proximaux/anatomopathologieRÉSUMÉ
The abundance of CaV2 voltage-gated calcium channels is linked to presynaptic homeostatic plasticity (PHP), a process that recalibrates synaptic strength to maintain the stability of neural circuits. However, the molecular and cellular mechanisms governing PHP and CaV2 channels are not completely understood. Here, we uncover a previously not described form of PHP in Caenorhabditis elegans, revealing an inverse regulatory relationship between the efficiency of neurotransmitter release and the abundance of UNC-2/CaV2 channels. Gain-of-function unc-2SL(S240L) mutants, which carry a mutation analogous to the one causing familial hemiplegic migraine type 1 in humans, showed markedly reduced channel abundance despite increased channel functionality. Reducing synaptic release in these unc-2SL(S240L) mutants restored channel levels to those observed in wild-type animals. Conversely, loss-of-function unc-2DA(D726A) mutants, which harbor the D726A mutation in the channel pore, exhibited a marked increase in channel abundance. Enhancing synaptic release in unc-2DA mutants reversed this increase in channel levels. Importantly, this homeostatic regulation of UNC-2 channel levels is accompanied by the structural remodeling of the active zone (AZ); specifically, unc-2DA mutants, which exhibit increased channel abundance, showed parallel increases in select AZ proteins. Finally, our forward genetic screen revealed that WWP-1, a HECT family E3 ubiquitin ligase, is a key homeostatic mediator that removes UNC-2 from synapses. These findings highlight a self-tuning PHP regulating UNC-2/CaV2 channel abundance along with AZ reorganization, ensuring synaptic strength and stability.
Sujet(s)
Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Agents neuromédiateurs , Animaux , Caenorhabditis elegans/métabolisme , Caenorhabditis elegans/génétique , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Agents neuromédiateurs/métabolisme , Terminaisons présynaptiques/métabolisme , Canaux calciques/métabolisme , Canaux calciques/génétique , Transmission synaptique/physiologie , Plasticité neuronale , Mutation , Canaux calciques de type N/métabolisme , Canaux calciques de type N/génétique , Neurones/métabolisme , Protéines membranairesRÉSUMÉ
Structures of complex networks are fundamental to system dynamics, where node state and connectivity patterns determine the cost of a control system, a key aspect in unraveling complexity. However, minimizing the energy required to control a system with the fewest input nodes remains an open problem. This study investigates the relationship between the structure of closed-connected function modules and control energy. We discovered that small structural adjustments, such as adding a few extended driver nodes, can significantly reduce control energy. Thus, we propose MInimal extended driver nodes in Energetic costs Reduction (MIER). Next, we transform the detection of MIER into a multi-objective optimization problem and choose an NSGA-II algorithm to solve it. Compared with the baseline methods, NSGA-II can approximate the optimal solution to the greatest extent. Through experiments using synthetic and real data, we validate that MIER can exponentially decrease control energy. Furthermore, random perturbation tests confirm the stability of MIER. Subsequently, we applied MIER to three representative scenarios: regulation of differential expression genes affected by cancer mutations in the human protein-protein interaction network, trade relations among developed countries in the world trade network, and regulation of body-wall muscle cells by motor neurons in Caenorhabditis elegans nervous network. The results reveal that the involvement of MIER significantly reduces control energy required for these original modules from a topological perspective. Additionally, MIER nodes enhance functionality, supplement key nodes, and uncover potential mechanisms. Overall, our work provides practical computational tools for understanding and presenting control strategies in biological, social, and neural systems.
Sujet(s)
Algorithmes , Caenorhabditis elegans , Caenorhabditis elegans/métabolisme , Humains , Animaux , Métabolisme énergétique , Cartes d'interactions protéiquesRÉSUMÉ
FOXO transcription factors modulate aging-related pathways and influence longevity in multiple species, but the transcriptional targets that mediate these effects remain largely unknown. Here, we identify an evolutionarily conserved FOXO target gene, Oxidative stress-responsive serine-rich protein 1 (OSER1), whose overexpression extends lifespan in silkworms, nematodes, and flies, while its depletion correspondingly shortens lifespan. In flies, overexpression of OSER1 increases resistance to oxidative stress, starvation, and heat shock, while OSER1-depleted flies are more vulnerable to these stressors. In silkworms, hydrogen peroxide both induces and is scavenged by OSER1 in vitro and in vivo. Knockdown of OSER1 in Caenorhabditis elegans leads to increased ROS production and shorter lifespan, mitochondrial fragmentation, decreased ATP production, and altered transcription of mitochondrial genes. Human proteomic analysis suggests that OSER1 plays roles in oxidative stress response, cellular senescence, and reproduction, which is consistent with the data and suggests that OSER1 could play a role in fertility in silkworms and nematodes. Human studies demonstrate that polymorphic variants in OSER1 are associated with human longevity. In summary, OSER1 is an evolutionarily conserved FOXO-regulated protein that improves resistance to oxidative stress, maintains mitochondrial functional integrity, and increases lifespan in multiple species. Additional studies will clarify the role of OSER1 as a critical effector of healthy aging.
Sujet(s)
Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Protéines de Drosophila , Facteurs de transcription Forkhead , Longévité , Stress oxydatif , Animaux , Longévité/génétique , Caenorhabditis elegans/génétique , Caenorhabditis elegans/physiologie , Caenorhabditis elegans/métabolisme , Humains , Protéines de Drosophila/métabolisme , Protéines de Drosophila/génétique , Facteurs de transcription Forkhead/métabolisme , Facteurs de transcription Forkhead/génétique , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Bombyx/génétique , Bombyx/métabolisme , Bombyx/physiologie , Drosophila melanogaster/génétique , Mitochondries/métabolisme , Mitochondries/génétique , Espèces réactives de l'oxygène/métabolisme , Régulation de l'expression des gènesRÉSUMÉ
Since double-stranded RNA (dsRNA) is effective for silencing a wide variety of genes, all genes are typically considered equivalent targets for such RNA interference (RNAi). Yet, loss of some regulators of RNAi in the nematode Caenorhabditis elegans can selectively impair the silencing of some genes. Here, we show that such selective requirements can be explained by an intersecting network of regulators acting on genes with differences in their RNA metabolism. In this network, the Maelstrom domain-containing protein RDE-10, the intrinsically disordered protein MUT-16, and the Argonaute protein NRDE-3 work together so that any two are required for silencing one somatic gene, but each is singly required for silencing another somatic gene, where only the requirement for NRDE-3 can be overcome by enhanced dsRNA processing. Quantitative models and their exploratory simulations led us to find that (1) changing cis-regulatory elements of the target gene can reduce the dependence on NRDE-3, (2) animals can recover from silencing in non-dividing cells, and (3) cleavage and tailing of mRNAs with UG dinucleotides, which makes them templates for amplifying small RNAs, are enriched within 'pUG zones' matching the dsRNA. Similar crosstalk between pathways and restricted amplification could result in apparently selective silencing by endogenous RNAs.
A variety of diseases are treated with therapeutics that switch off genes via a mechanism called RNA interference (or RNAi for short). Each gene has the instructions cells need to build a particular protein. To achieve this, the DNA sequence must first be copied into a single-stranded mRNA molecule than can be translated into protein. RNAi interferes with this process by generating a double-stranded RNA molecule which contains the same DNA sequence as the gene being turned off. A set of proteins (known as regulators) then progressively trigger a series of events that allow the double-stranded RNA to be processed into short pieces that interact with the mRNA and target it for degradation. While cells use RNAi to regulate the expression of their own genes, researchers can also artificially switch off genes by synthesizing double-stranded RNA molecules in the laboratory. However, some genes are trickier to turn off than others, and why this happens is poorly understood. To investigate, Knudsen-Palmer et al. studied how two genes (bli-1 and unc-22) are switched off by RNAi in the roundworm Caenorhabditis elegans. A previous study discovered that bli-1 and unc-22 require different regulators for their expression to be disrupted. Knudsen-Palmer et al. found that this was because the RNAi process involves an intersecting network of multiple regulators, rather than a linear pathway of regulators working one after the other. For example, bli-1 requires three regulators (MUT-16, RDE-10 and NRDE-3), whereas unc-22 only needs any two of these regulators to be switched off. Further experiments revealed that which regulators are required depends on how the gene being silenced is naturally regulated in the cell. Analysis through a computational model showed that the regulators needed for RNAi could be altered in many ways, including by changing the regions that regulators bind to on the mRNA of the target gene. These findings provide new insights into why some genes respond differently to double-stranded RNA molecules. They also suggest that testing how natural regulation of a target gene influences its response to the RNAi process could potentially lead to better therapeutics.
Sujet(s)
Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Interférence par ARN , ARN double brin , Caenorhabditis elegans/génétique , Caenorhabditis elegans/métabolisme , Animaux , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , ARN double brin/métabolisme , ARN double brin/génétique , Protéines de liaison à l'ARNRÉSUMÉ
Mechanical stress during muscle contraction is a constant threat to proteome integrity. However, there is a lack of experimental systems to identify critical proteostasis regulators under mechanical stress conditions. Here, we present the transgenic Caenorhabditis elegans model OptIMMuS (Optogenetic Induction of Mechanical Muscle Stress) to study changes in the proteostasis network associated with mechanical forces. Repeated blue light exposure of a muscle-expressed Chlamydomonas rheinhardii channelrhodopsin-2 variant results in sustained muscle contraction and mechanical stress. Using OptIMMuS, combined with proximity labeling and mass spectrometry, we identify regulators that cooperate with the myosin-directed chaperone UNC-45 in muscle proteostasis. One of these is the TRIM E3 ligase NHL-1, which interacts with UNC-45 and muscle myosin in genetic epistasis and co-immunoprecipitation experiments. We provide evidence that the ubiquitylation activity of NHL-1 regulates myosin levels and functionality under mechanical stress. In the future, OptIMMuS will help to identify muscle-specific proteostasis regulators of therapeutic relevance.
Sujet(s)
Animal génétiquement modifié , Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Optogénétique , Homéostasie protéique , Contrainte mécanique , Ubiquitin-protein ligases , Ubiquitination , Caenorhabditis elegans/métabolisme , Caenorhabditis elegans/génétique , Animaux , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Ubiquitin-protein ligases/métabolisme , Ubiquitin-protein ligases/génétique , Myosines/métabolisme , Myosines/génétique , Contraction musculaire/physiologie , Muscles/métabolisme , Chaperons moléculairesRÉSUMÉ
Mitosis in early embryos often proceeds at a rapid pace, but how this pace is achieved is not understood. Here, we show that cyclin B3 is the dominant driver of rapid embryonic mitoses in the C. elegans embryo. Cyclins B1 and B2 support slow mitosis (NEBD to anaphase â¼600 s), but the presence of cyclin B3 dominantly drives the approximately threefold faster mitosis observed in wildtype. Multiple mitotic events are slowed down in cyclin B1 and B2-driven mitosis, and cyclin B3-associated Cdk1 H1 kinase activity is â¼25-fold more active than cyclin B1-associated Cdk1. Addition of cyclin B1 to fast cyclin B3-only mitosis introduces an â¼60-s delay between completion of chromosome alignment and anaphase onset; this delay, which is important for segregation fidelity, is dependent on inhibitory phosphorylation of the anaphase activator Cdc20. Thus, cyclin B3 dominance, coupled to a cyclin B1-dependent delay that acts via Cdc20 phosphorylation, sets the rapid pace and ensures mitotic fidelity in the early C. elegans embryo.
Sujet(s)
Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Cycline B1 , Embryon non mammalien , Mitose , Animaux , Caenorhabditis elegans/embryologie , Caenorhabditis elegans/métabolisme , Caenorhabditis elegans/génétique , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Cycline B1/métabolisme , Cycline B1/génétique , Embryon non mammalien/métabolisme , Phosphorylation , Protéine-kinase CDC2/métabolisme , Protéine-kinase CDC2/génétique , Cycline B/métabolisme , Cycline B/génétique , Protéines Cdc20/métabolisme , Protéines Cdc20/génétique , Cycline B2/métabolisme , Cycline B2/génétiqueRÉSUMÉ
Constructing gene regulatory networks is a widely adopted approach for investigating gene regulation, offering diverse applications in biology and medicine. A great deal of research focuses on using time series data or single-cell RNA-sequencing data to infer gene regulatory networks. However, such gene expression data lack either cellular or temporal information. Fortunately, the advent of time-lapse confocal laser microscopy enables biologists to obtain tree-shaped gene expression data of Caenorhabditis elegans, achieving both cellular and temporal resolution. Although such tree-shaped data provide abundant knowledge, they pose challenges like non-pairwise time series, laying the inaccuracy of downstream analysis. To address this issue, a comprehensive framework for data integration and a novel Bayesian approach based on Boolean network with time delay are proposed. The pre-screening process and Markov Chain Monte Carlo algorithm are applied to obtain the parameter estimates. Simulation studies show that our method outperforms existing Boolean network inference algorithms. Leveraging the proposed approach, gene regulatory networks for five subtrees are reconstructed based on the real tree-shaped datatsets of Caenorhabditis elegans, where some gene regulatory relationships confirmed in previous genetic studies are recovered. Also, heterogeneity of regulatory relationships in different cell lineage subtrees is detected. Furthermore, the exploration of potential gene regulatory relationships that bear importance in human diseases is undertaken. All source code is available at the GitHub repository https://github.com/edawu11/BBTD.git.
Sujet(s)
Algorithmes , Caenorhabditis elegans , Réseaux de régulation génique , Caenorhabditis elegans/génétique , Animaux , Théorème de Bayes , Biologie informatique/méthodes , Chaines de Markov , Analyse de profil d'expression de gènes/méthodesRÉSUMÉ
The heat-shock response plays a key role in the immune defence against viruses across various organisms. Studies on model organisms have shown that inducing this response prior to viral exposure enhances host resistance to infections, while deficient responses make individuals more susceptible. Moreover, viruses rely on components of the heat-shock response for their own stability and viral infections improve thermal tolerance in plants, giving infected individuals an advantage in extreme conditions, which aids the virus in replication and transmission. Here, we examine the interaction between the nematode Caenorhabditis elegans and its natural pathogen the Orsay virus (OrV) under heat stress. We found that OrV infection leads to differential expression of heat-stress-related genes, and infected populations show increased resistance to heat-shock. This resistance correlates with increased expression of argonautes alg-1 and alg-2, which are crucial for survival after heat-shock and for OrV replication. Overall, our study suggests an environmental-dependent mutualistic relationship between the nematode and OrV, potentially expanding the animal's ecological niche and providing the virus with extra opportunities for replication and adaptation to extreme conditions.
Sujet(s)
Caenorhabditis elegans , Réaction de choc thermique , Animaux , Caenorhabditis elegans/virologie , Caenorhabditis elegans/physiologie , Caenorhabditis elegans/génétique , Caenorhabditis elegans/immunologie , Protéines de Caenorhabditis elegans/génétique , Protéines de Caenorhabditis elegans/métabolisme , Interactions hôte-pathogèneRÉSUMÉ
BACKGROUND: Sensory systems evolved intricate designs to accurately encode perplexing environments. However, this encoding task may become particularly challenging for animals harboring a small number of sensory neurons. Here, we studied how the compact resource-limited chemosensory system of Caenorhabditis elegans uniquely encodes a range of chemical stimuli. RESULTS: We find that each stimulus is encoded using a small and unique subset of neurons, where only a portion of the encoding neurons sense the stimulus directly, and the rest are recruited via inter-neuronal communication. Furthermore, while most neurons show stereotypical response dynamics, some neurons exhibit versatile dynamics that are either stimulus specific or network-activity dependent. Notably, it is the collective dynamics of all responding neurons which provides valuable information that ultimately enhances stimulus identification, particularly when required to discriminate between closely related stimuli. CONCLUSIONS: Together, these findings demonstrate how a compact and resource-limited chemosensory system can efficiently encode and discriminate a diverse range of chemical stimuli.
Sujet(s)
Caenorhabditis elegans , Cellules chimioréceptrices , Animaux , Caenorhabditis elegans/physiologie , Cellules chimioréceptrices/physiologie , Cellules réceptrices sensorielles/physiologieRÉSUMÉ
Neurons coordinate inter-tissue protein homeostasis to systemically manage cytotoxic stress. In response to neuronal mitochondrial stress, specific neuronal signals coordinate the systemic mitochondrial unfolded protein response (UPRmt) to promote organismal survival. Yet, whether chemical neurotransmitters are sufficient to control the UPRmt in physiological conditions is not well understood. Here, we show that gamma-aminobutyric acid (GABA) inhibits, and acetylcholine (ACh) promotes the UPRmt in the Caenorhabditis elegans intestine. GABA controls the UPRmt by regulating extra-synaptic ACh release through metabotropic GABAB receptors GBB-1/2. We find that elevated ACh levels in animals that are GABA-deficient or lack ACh-degradative enzymes induce the UPRmt through ACR-11, an intestinal nicotinic α7 receptor. This neuro-intestinal circuit is critical for non-autonomously regulating organismal survival of oxidative stress. These findings establish chemical neurotransmission as a crucial regulatory layer for nervous system control of systemic protein homeostasis and stress responses.
Sujet(s)
Acétylcholine , Caenorhabditis elegans , Mitochondries , Transduction du signal , Animaux , Acétylcholine/métabolisme , Récepteur nicotinique de l'acétylcholine alpha7/métabolisme , Récepteur nicotinique de l'acétylcholine alpha7/génétique , Caenorhabditis elegans/métabolisme , Caenorhabditis elegans/génétique , Caenorhabditis elegans/physiologie , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Acide gamma-amino-butyrique/métabolisme , Intestins/physiologie , Mitochondries/métabolisme , Neurones/métabolisme , Stress oxydatif , Récepteurs GABA-B/métabolisme , Récepteurs GABA-B/génétique , Stress physiologique , Transmission synaptique/physiologie , Réponse aux protéines mal repliéesRÉSUMÉ
A recently reported Schizophrenia-associated genetic variant in the 3'UTR of the human furin gene, a homolog of C. elegans kpc-1, highlights an important role of the furin 3'UTR in neuronal development. We isolate three kpc-1 mutants that display abnormal dendrite arborization in PVD neurons and defective male mating behaviors. We show that the kpc-1 3'UTR participates in dendrite branching and self-avoidance. The kpc-1 3'UTR facilitates mRNA localization to branching points and contact points between sibling dendrites and promotes translation efficiency. A predicted secondary structural motif in the kpc-1 3'UTR is required for dendrite self-avoidance. Animals with over-expression of DMA-1, a PVD dendrite receptor, exhibit similar dendrite branching and self-avoidance defects that are suppressed with kpc-1 over-expression. Our results support a model in which KPC-1 proteins are synthesized at branching points and contact points to locally down-regulate DMA-1 receptors to promote dendrite branching and self-avoidance of a mechanosensory neuron important for male courtship.
Sujet(s)
Régions 3' non traduites , Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Parade nuptiale , Dendrites , ARN messager , Animaux , Protéines de Caenorhabditis elegans/génétique , Protéines de Caenorhabditis elegans/métabolisme , Mâle , Dendrites/métabolisme , Dendrites/génétique , Caenorhabditis elegans/génétique , Caenorhabditis elegans/métabolisme , Régions 3' non traduites/génétique , ARN messager/génétique , ARN messager/métabolisme , Biosynthèse des protéines , Comportement sexuel chez les animaux/physiologie , Humains , Mutation , Protéines membranairesRÉSUMÉ
The biological clock in eukaryotes controls daily rhythms in physiology and behavior. It displays a complex organization that involves the molecular transcriptional clock and the redox oscillator which may coordinately work to control cellular rhythms. The redox oscillator has emerged very early in evolution in adaptation to the environmental changes in O2 levels and has been shown to regulate daily rhythms in glycerolipid (GL) metabolism in different eukaryotic cells. GLs are key components of lipid droplets (LDs), intracellular storage organelles, present in all living organisms, and essential for energy and lipid homeostasis regulation and survival; however, the cell bioenergetics status is not constant across time and depends on energy demands. Thus, the formation and degradation of LDs may reflect a time-dependent process following energy requirements. This work investigated the presence of metabolic rhythms in LD content along evolution by studying prokaryotic and eukaryotic cells and organisms. We found sustained temporal oscillations in LD content in Pseudomonas aeruginosa bacteria and Caenorhabditis elegans synchronized by temperature cycles, in serum-shock synchronized human embryonic kidney cells (HEK 293 cells) and brain tumor cells (T98G and GL26) after a dexamethasone pulse. Moreover, in synchronized T98G cells, LD oscillations were altered by glycogen synthase kinase-3 (GSK-3) inhibition that affects the cytosolic activity of the metabolic oscillator or by knocking down LIPIN-1, a key GL synthesizing enzyme. Overall, our findings reveal the existence of metabolic oscillations in terms of LD content highly conserved across evolutionary scales notwithstanding variations in complexity, regulation, and cell organization.
Sujet(s)
Caenorhabditis elegans , Gouttelettes lipidiques , Pseudomonas aeruginosa , Humains , Gouttelettes lipidiques/métabolisme , Animaux , Caenorhabditis elegans/métabolisme , Caenorhabditis elegans/génétique , Cellules HEK293 , Pseudomonas aeruginosa/métabolisme , Pseudomonas aeruginosa/génétique , Horloges biologiques/génétique , Évolution biologique , Métabolisme lipidique/génétique , Rythme circadien/génétique , Rythme circadien/physiologieRÉSUMÉ
The autophagy-lysosomal pathway enables the controlled degradation of cellular contents. Nucleophagy is the selective autophagic recycling of nuclear components upon delivery to the lysosome. Although methods to monitor and quantify autophagy as well as selective types of autophagy have been developed and implemented in cells and in vivo, methods monitoring nucleophagy remain scarce. Here, we describe a procedure to monitor the autophagic engagement of an endogenous nuclear envelope component, i.e., ANC-1, the nematode homologue of the mammalian Nesprins in vivo, utilizing super-resolution microscopy.
Sujet(s)
Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Animaux , Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Autophagie/physiologie , Lysosomes/métabolisme , Enveloppe nucléaire/métabolisme , Noyau de la cellule/métabolisme , MacroautophagieRÉSUMÉ
Preserving mitochondrial homeostasis is vital, particularly for the energetically demanding and metabolically active nerve cells. Mitophagy, the selective autophagic removal of mitochondria, stands out as a prominent mechanism for efficient mitochondrial turnover, which is crucial for proper neuronal development and function. Dysfunctional mitochondria and disrupted mitophagy pathways have been linked to a diverse array of neurological disorders. The nematode Caenorhabditis elegans, with its well-defined nervous system, serves as an excellent model to unravel the intricate involvement of mitophagy in developing neurons. This chapter describes the use of Rosella biosensor in C. elegans to monitor neuronal mitophagy, providing a user-friendly platform for screening genes and drugs affecting mitophagic pathways under physiological conditions or in the context of neurodevelopmental pathologies.
Sujet(s)
Caenorhabditis elegans , Mitochondries , Mitophagie , Neurones , Animaux , Caenorhabditis elegans/métabolisme , Neurones/métabolisme , Neurones/cytologie , Mitochondries/métabolisme , Techniques de biocapteur/méthodes , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétiqueRÉSUMÉ
Amyloid formation by α-synuclein (αSyn) occurs in Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies. Deciphering the residues that regulate αSyn amyloid fibril formation will not only provide mechanistic insight but may also reveal targets to prevent and treat disease. Previous investigations have identified several regions of αSyn to be important in the regulation of amyloid formation, including the non-amyloid-ß component (NAC), P1 region (residues 36 to 42), and residues in the C-terminal domain. Recent studies have also indicated the importance of the N-terminal region of αSyn for both its physiological and pathological roles. Here, the role of residues 2 to 7 in the N-terminal region of αSyn is investigated in terms of their ability to regulate amyloid fibril formation in vitro and in vivo. Deletion of these residues (αSynΔN7) slows the rate of fibril formation in vitro and reduces the capacity of the protein to be recruited by wild-type (αSynWT) fibril seeds, despite cryo-EM showing a fibril structure consistent with those of full-length αSyn. Strikingly, fibril formation of αSynΔN7 is not induced by liposomes, despite the protein binding to liposomes with similar affinity to αSynWT. A Caenorhabditis elegans model also showed that αSynΔN7::YFP forms few puncta and lacks motility and lifespan defects typified by expression of αSynWT::YFP. Together, the results demonstrate the involvement of residues 2 to 7 of αSyn in amyloid formation, revealing a target for the design of amyloid inhibitors that may leave the functional role of the protein in membrane binding unperturbed.
Sujet(s)
Amyloïde , Caenorhabditis elegans , alpha-Synucléine , alpha-Synucléine/métabolisme , alpha-Synucléine/génétique , alpha-Synucléine/composition chimique , Amyloïde/métabolisme , Caenorhabditis elegans/métabolisme , Animaux , Humains , Lipides/composition chimique , Maladie de Parkinson/métabolisme , Maladie de Parkinson/génétique , Maladie de Parkinson/anatomopathologieRÉSUMÉ
In C. elegans mechanisms by which peripheral organs relay internal state information to the nervous system remain unknown, although strong evidence suggests that such signals do exist. Here we report the discovery of a peptide of the ancestral insulin superfamily called INS-7 that functions as an enteroendocrine peptide and is secreted from specialized cells of the intestine. INS-7 secretion is stimulated by food withdrawal, increases during fasting and acts as a bona fide gut-to-brain peptide that attenuates the release of a neuropeptide that drives fat loss in the periphery. Thus, INS-7 functions as a homeostatic signal from the intestine that gates the neuronal drive to stimulate fat loss during food shortage. Mechanistically, INS-7 functions as an antagonist at the canonical DAF-2 receptor and functions via FOXO and AMPK signaling in ASI neurons. Phylogenetic analysis suggests that INS-7 bears greater resemblance to members of the broad insulin/relaxin superfamily than to conventional mammalian insulin and IGF peptides. The discovery of an endogenous insulin antagonist secreted by specialized intestinal cells with enteroendocrine functions suggests unexpected and important properties of the intestine and its role in directing neuronal functions.
Sujet(s)
Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Homéostasie , Insuline , Neurones , Animaux , Neurones/métabolisme , Neurones/effets des médicaments et des substances chimiques , Insuline/métabolisme , Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Récepteur à l'insuline/métabolisme , Récepteur à l'insuline/antagonistes et inhibiteurs , Transduction du signal/effets des médicaments et des substances chimiques , Encéphale/métabolisme , Encéphale/effets des médicaments et des substances chimiques , Neuropeptides/métabolisme , Facteurs de transcription Forkhead/métabolisme , Facteurs de transcription Forkhead/génétique , Intestins , Phylogenèse , Jeûne , Muqueuse intestinale/métabolismeRÉSUMÉ
Fertility requires the faithful proliferation of germ cells and their differentiation into gametes. Controlling these cellular states demands precise timing and expression of gene networks. Nucleic acid binding proteins (NBPs) play critical roles in gene expression networks that influence germ cell development. There has, however, been no functional analysis of the entire NBP repertoire in controlling in vivo germ cell development. Here, we analyzed germ cell states and germline architecture to systematically investigate the function of 364 germline-expressed NBPs in the Caenorhabditis elegans germ line. Using germline-specific knockdown, automated germ cell counting, and high-content analysis of germ cell nuclei and plasma membrane organization, we identify 156 NBPs with discrete autonomous germline functions. By identifying NBPs that control the germ cell cycle, proliferation, differentiation, germline structure and fertility, we have created an atlas for mechanistic dissection of germ cell behavior and gamete production.
Sujet(s)
Protéines de Caenorhabditis elegans , Caenorhabditis elegans , Cellules germinales , Animaux , Caenorhabditis elegans/génétique , Caenorhabditis elegans/métabolisme , Cellules germinales/métabolisme , Protéines de Caenorhabditis elegans/métabolisme , Protéines de Caenorhabditis elegans/génétique , Régulation de l'expression des gènes au cours du développement , Différenciation cellulaire/génétique , Protéines de liaison à l'ARN/métabolisme , Protéines de liaison à l'ARN/génétique , Fécondité/génétique , Protéines de liaison à l'ADN/métabolisme , Protéines de liaison à l'ADN/génétique , Prolifération cellulaire/génétique , Cycle cellulaire/génétique , Mâle , Réseaux de régulation géniqueRÉSUMÉ
The Caenorhabditis elegans germline is arranged spatiotemporally and is therefore a powerful model system for the interrogation of meiotic molecular dynamics. Coupling this property with the temporal control that the auxin-inducible degron (AID) system allows can unveil new/unappreciated roles for critical meiotic factors in specific germline regions. Here we describe a widely used approach for the introduction of degron tags to specific targets and provide a procedure for applying the AID system to C. elegans meiotic DSB repair dynamics in the germline.