RESUMO
Neuronal differentiation is highly coordinated through a cascade of gene expression, mediated via interactions between transacting transcription factors and cis-regulatory elements of their target genes. However, the mechanisms of transcriptional regulation that determine neuronal cell-fate are not fully understood. Here, we show that the nuclear transcription factor Y (NF-Y) subunit, NFYA-1, is necessary and sufficient to express the flp-3 neuropeptide gene in the IL1 neurons of C. elegans. flp-3 expression is decreased in dorsal and lateral, but not ventral IL1s of nfya-1 mutants. The expression of another terminally differentiated gene, eat-4 vesicular glutamate transporter, is abolished, whereas the unc-8 DEG/ENaC gene and pan-neuronal genes are expressed normally in IL1s of nfya-1 mutants. nfya-1 is expressed in and acts in IL1s to regulate flp-3 and eat-4 expression. Ectopic expression of NFYA-1 drives the expression of flp-3 gene in other cell-types. Promoter analysis of IL1-expressed genes results in the identification of several cisregulatory motifs which are necessary for IL1 expression, including a putative CCAAT-box located in the flp-3 promoter that NFYA-1 directly interacts with. NFYA-1 and NFYA-2, together with NFYB-1 and NFYC-1, exhibit partly or fully redundant roles in the regulation of flp-3 or unc-8 expression, respectively. Taken together, our data indicate that the NF-Y complex regulates neuronal subtype-specification via regulating a set of terminal-differentiation genes. [BMB Reports 2023; 56(3): 153-159].
Assuntos
Proteínas de Caenorhabditis elegans , Fatores de Transcrição , Animais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Regulação da Expressão Gênica , Regiões Promotoras Genéticas/genética , Neurônios/metabolismo , Canais Iônicos/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismoRESUMO
Animals detect and discriminate countless environmental chemicals for their well-being and survival. Although a single chemical can trigger opposing behavioral responses depending on its concentration, the mechanisms underlying such a concentration-dependent switching remain poorly understood. Here, we show that C. elegans exhibits either attraction or avoidance of the bacteria-derived volatile chemical dimethyl trisulfide (DMTS) depending on its concentration. This behavioral switching is mediated by two different types of chemosensory neurons, both of which express the DMTS-sensitive seven-transmembrane G protein-coupled receptor (GPCR) SRI-14. These two sensory neurons share downstream interneurons that process and translate DMTS signals via distinct glutamate receptors to generate the appropriate behavioral outcome. Thus, our results present one mechanism by which an animal connects two distinct types of chemosensory neurons detecting a common ligand to alternate downstream circuitry, thus efficiently switching between specific behavioral programs based on ligand concentration.
Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans , Receptores Odorantes/metabolismo , Animais , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/genética , Ligantes , Receptores Acoplados a Proteínas G/genética , Células Receptoras SensoriaisRESUMO
The characteristics or aspects of important fiducial points (FPs) in the electrocardiogram (ECG) signal are complicated because of various factors, such as non-stationary effects and low signal-to-noise ratio. Due to the various noises caused by the ECG signal measurement environment and by typical ECG signal deformation due to heart diseases, detecting such FPs becomes a challenging task. In this study, we introduce a novel PQRST complex detector using a one-dimensional bilateral filter (1DBF) and the temporal characteristics of FPs. The 1DBF with noise suppression and edge preservation preserves the P- or T-wave whereas it suppresses the QRS-interval. The 1DBF acts as a background predictor for predicting the background corresponding to the P- and T-waves and the remaining flat interval excluding the QRS-interval. The R-peak and QRS-interval are founded by the difference of the original ECG signal and the predicted background signal. Then, the Q- and S-points and the FPs related to the P- and T-wave are sequentially detected using the determined searching range and detection order based on the detected R-peak. The detection performance of the proposed method is analyzed through the MIT-BIH database (MIT-DB) and the QT database (QT-DB).
Assuntos
Algoritmos , Processamento de Sinais Assistido por Computador , Arritmias Cardíacas , Bases de Dados Factuais , Eletrocardiografia , HumanosRESUMO
The clinical research faces numerous challenges, from patient enrollment to data privacy concerns and regulatory requirements to spiraling costs. Blockchain technology has the potential to overcome these challenges, thus making clinical trials transparent and enhancing public trust in a fair and open process with all stakeholders because of its distinct features such as data immutability and transparency. This paper proposes a permissioned blockchain platform to ensure clinical data transparency and provides secure clinical trial-related solutions. We explore the core functionalities of blockchain applied to clinical trials and illustrate its general principle concretely. These clinical trial operations are automated using the smart contract, which ensures traceability, prevents a posteriori reconstruction, and securely automates the clinical trial. A web-based user interface is also implemented to visualize the data from the blockchain and ease the interaction with the blockchain network. A proof of concept is implemented on Hyperledger Fabric in the case study of clinical management for multiple clinical trials to demonstrate the designed approach's feasibility. Lastly, the experiment results demonstrate the efficiency and usability of the proposed platform.
Assuntos
Blockchain , Ensaios Clínicos como Assunto , Segurança Computacional , Humanos , Reprodutibilidade dos TestesRESUMO
Despite the known importance of the transmembrane domain (TMD) of syndecan receptors in cell adhesion and signaling, the molecular basis for syndecan TMD function remains unknown. Using in vivo invertebrate models, we found that mammalian syndecan-2 rescued both the guidance defects in C. elegans hermaphrodite-specific neurons and the impaired development of the midline axons of Drosophila caused by the loss of endogenous syndecan. These compensatory effects, however, were reduced significantly when syndecan-2 dimerization-defective TMD mutants were introduced. To further investigate the role of the TMD, we generated a chimera, 2eTPC, comprising the TMD of syndecan-2 linked to the cytoplasmic domain of platelet-derived growth factor receptor (PDGFR). This chimera exhibited SDS-resistant dimer formation that was lost in the corresponding dimerization-defective syndecan-2 TMD mutant, 2eT(GL)PC. Moreover, 2eTPC specifically enhanced Tyr 579 and Tyr 857 phosphorylation in the PDGFR cytoplasmic domain, while the TMD mutant failed to support such phosphorylation. Finally, 2eTPC, but not 2eT(GL)PC, induced phosphorylation of Src and PI3 kinase (known downstream effectors of Tyr 579 phosphorylation) and promoted Src-mediated migration of NIH3T3 cells. Taken together, these data suggest that the TMD of a syndecan-2 specifically regulates receptor cytoplasmic domain function and subsequent downstream signaling events controlling cell behavior.
Assuntos
Adesão Celular , Domínios Proteicos , Transdução de Sinais , Sindecana-2/metabolismo , Animais , Células HEK293 , Humanos , Camundongos , Células NIH 3T3 , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Multimerização Proteica , Processamento de Proteína Pós-Traducional , Sindecana-2/fisiologia , Quinases da Família src/metabolismoRESUMO
Animals can adapt to dynamic environmental conditions by modulating their developmental programs. Understanding the genetic architecture and molecular mechanisms underlying developmental plasticity in response to changing environments is an important and emerging area of research. Here, we show a novel role of cAMP response element binding protein (CREB)-encoding crh-1 gene in developmental polyphenism of C. elegans. Under conditions that promote normal development in wild-type animals, crh-1 mutants inappropriately form transient pre-dauer (L2d) larvae and express the L2d marker gene. L2d formation in crh-1 mutants is specifically induced by the ascaroside pheromone ascr#5 (asc-ωC3; C3), and crh-1 functions autonomously in the ascr#5-sensing ASI neurons to inhibit L2d formation. Moreover, we find that CRH-1 directly binds upstream of the daf-7 TGF-ß locus and promotes its expression in the ASI neurons. Taken together, these results provide new insight into how animals alter their developmental programs in response to environmental changes.
Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Fatores de Transcrição/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Adaptação Fisiológica/genética , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Ciclo Celular , Processos de Crescimento Celular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/fisiologia , Expressão Gênica/genética , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Larva/genética , Larva/crescimento & desenvolvimento , Feromônios/metabolismo , Células Receptoras Sensoriais/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição/genética , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/fisiologiaRESUMO
In animals, proper locomotion is crucial to find mates and foods and avoid predators or dangers. Multiple sensory systems detect external and internal cues and integrate them to modulate motor outputs. Proprioception is the internal sense of body position, and proprioceptive control of locomotion is essential to generate and maintain precise patterns of movement or gaits. This proprioceptive feedback system is conserved in many animal species and is mediated by stretch-sensitive receptors called proprioceptors. Recent studies have identified multiple proprioceptive neurons and proprioceptors and their roles in the locomotion of various model organisms. In this review we describe molecular and neuronal mechanisms underlying proprioceptive feedback systems in C. elegans, Drosophila, and mice. [BMB Reports 2021; 54(8): 393-402].
Assuntos
Atividade Motora/fisiologia , Propriocepção/genética , Propriocepção/fisiologia , Animais , Caenorhabditis elegans , Drosophila , Retroalimentação Sensorial/fisiologia , Humanos , Cinestesia/fisiologia , Locomoção/fisiologia , Camundongos , Neurônios Motores/fisiologia , Equilíbrio Postural/fisiologia , Células Receptoras Sensoriais/fisiologiaRESUMO
Dietary restriction extends lifespan in various organisms by reducing the levels of both nutrients and non-nutritional food-derived cues. However, the identity of specific food-derived chemical cues that alter lifespan remains unclear. Here, we identified several volatile attractants that decreased the longevity on food deprivation, a dietary restriction regimen in Caenorhabditis elegans. In particular, we found that the odor of diacetyl decreased the activity of DAF-16/FOXO, a life-extending transcription factor acting downstream of insulin/IGF-1 signaling. We then demonstrated that the odor of lactic acid bacteria, which produce diacetyl, reduced the nuclear accumulation of DAF-16/FOXO. Unexpectedly, we showed that the odor of diacetyl decreased longevity independently of two established diacetyl receptors, ODR-10 and SRI-14, in sensory neurons. Thus, diacetyl, a food-derived odorant, may shorten food deprivation-induced longevity via decreasing the activity of DAF-16/FOXO through binding to unidentified receptors.
Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Diacetil/efeitos adversos , Fatores de Transcrição Forkhead/metabolismo , Odorantes/análise , Animais , Dietoterapia , Regulação para Baixo , LongevidadeRESUMO
Caenorhabditis elegans secretes a complex cocktail of small chemicals collectively called ascaroside pheromones which serves as a chemical language for intra-species communication. Subsets of ascarosides have been shown to mediate a broad spectrum of C. elegans behavior and development, such as gender-specific attraction, repulsion, aggregation, olfactory plasticity, and dauer formation. Recent studies show that specific components of ascarosides elicit a rapid avoidance response that allows animals to avoid predators and escape from unfavorable conditions. Moreover, this avoidance behavior is modulated by external conditions, internal states, and previous experience, indicating that pheromone avoidance behavior is highly plastic. In this review, we describe molecular and circuit mechanisms underlying plasticity in pheromone avoidance behavior which pave a way to better understanding circuit mechanisms underlying behavioral plasticity in higher animals, including humans.
Assuntos
Adaptação Fisiológica/fisiologia , Aprendizagem da Esquiva/fisiologia , Caenorhabditis elegans/fisiologia , Feromônios/fisiologia , Animais , Conectoma , Comportamento Alimentar/fisiologia , Previsões , Glicolipídeos/química , Glicolipídeos/fisiologia , Lipídeos/química , Lipídeos/fisiologia , Nematoides/fisiologia , Vias Neurais/fisiologia , Feromônios/química , Especificidade da EspécieRESUMO
Fas-apoptotic inhibitory molecule 2 (FAIM2) is a member of the transmembrane BAX inhibitor motif-containing (TMBIM) family. TMBIM family is comprised of six anti-apoptotic proteins that suppress cell death by regulating endoplasmic reticulum Ca2+ homeostasis. Recent studies have implicated two TMBIM proteins, GRINA and BAX Inhibitor-1, in mediating cytoprotection via autophagy. However, whether FAIM2 plays a role in autophagy has been unknown. Here we show that FAIM2 localizes to the lysosomes at basal state and facilitates autophagy through interaction with microtubule-associated protein 1 light chain 3 proteins in human neuroblastoma SH-SY5Y cells. FAIM2 overexpression increased autophagy flux, while autophagy flux was impaired in shRNA-mediated knockdown (shFAIM2) cells, and the impairment was more evident in the presence of rapamycin. In shFAIM2 cells, autophagosome maturation through fusion with lysosomes was impaired, leading to accumulation of autophagosomes. A functional LC3-interacting region motif within FAIM2 was essential for the interaction with LC3 and rescue of autophagy flux in shFAIM2 cells while LC3-binding property of FAIM2 was dispensable for the anti-apoptotic function in response to Fas receptor-mediated apoptosis. Suppression of autophagosome maturation was also observed in a null mutant of Caenorhabditis elegans lacking xbx-6, the ortholog of FAIM2. Our study suggests that FAIM2 is a novel regulator of autophagy mediating autophagosome maturation through the interaction with LC3.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Autofagossomos/fisiologia , Lisossomos/fisiologia , Proteínas de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Motivos de Aminoácidos , Animais , Apoptose , Proteínas Reguladoras de Apoptose/genética , Autofagia/efeitos dos fármacos , Caenorhabditis elegans/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Imunossupressores/farmacologia , Proteínas de Membrana Lisossomal/genética , Proteínas de Membrana Lisossomal/metabolismo , Proteínas de Membrana/genética , Proteínas Associadas aos Microtúbulos/genética , Plasmídeos , Transporte Proteico , Sirolimo/farmacologiaRESUMO
Animals need to be able to alter their developmental and behavioral programs in response to changing environmental conditions. This developmental and behavioral plasticity is mainly mediated by changes in gene expression. The knowledge of the mechanisms by which environmental signals are transduced and integrated to modulate changes in sensory gene expression is limited. Exposure to ascaroside pheromone has been reported to alter the expression of a subset of putative G protein-coupled chemosensory receptor genes in the ASI chemosensory neurons of C. elegans (Kim et al., 2009; Nolan et al., 2002; Peckol et al., 1999). Here we show that ascaroside pheromone reversibly represses expression of the str-3 chemoreceptor gene in the ASI neurons. Repression of str-3 expression can be initiated only at the L1 stage, but expression is restored upon removal of ascarosides at any developmental stage. Pheromone receptors including SRBC-64/66 and SRG-36/37 are required for str-3 repression. Moreover, pheromone-mediated str-3 repression is mediated by FLP-18 neuropeptide signaling via the NPR-1 neuropeptide receptor. These results suggest that environmental signals regulate chemosensory gene expression together with internal neuropeptide signals which, in turn, modulate behavior.
Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Genes de Helmintos , Neuropeptídeos/metabolismo , Feromônios/farmacologia , Receptores Odorantes/genética , Transdução de Sinais , Animais , Caenorhabditis elegans/efeitos dos fármacos , Proteínas de Caenorhabditis elegans/metabolismo , Comportamento Alimentar/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/genética , Mutação/genética , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Óvulo/metabolismo , Receptores de Neuropeptídeo Y , Receptores Odorantes/metabolismo , Transdução de Sinais/efeitos dos fármacos , TemperaturaRESUMO
Traditional surgical training methods to teach young doctors have changed because of the emergence of animal models. The present article summarizes a protocol for bilateral axillo-breast approach (BABA) endoscopic thyroidectomy in a pig model. All procedures were approved by the local ethics committee and the pigs were anesthetized by a veterinarian. Formation of the flap involved skin marking, hydrodissection, blunt dissection and, finally, trocar insertion. BABA endoscopic thyroidectomy is performed by midline division, identification of the thyroid, thyroidectomy and, finally, surveillance of bleeding. Four cases of endoscopic thyroidectomy using porcine models were performed using the BABA approach. The mean weight of the pigs was 60 kg, and the mean operation time was 74.3 minutes. All surgeries were completed without complications. Surgical training for BABA endoscopic thyroidectomy using a porcine model is a valuable education method for young surgeons who need practice before performing surgery on human patients.
Assuntos
Endoscopia/métodos , Tireoidectomia/métodos , Animais , Mama , Endoscopia/educação , Feminino , Modelos Animais , Duração da Cirurgia , Retalhos Cirúrgicos , Suínos , Tireoidectomia/educaçãoRESUMO
Animals change sensory responses and their eventual behaviors, depending on their internal metabolic status and external food availability. However, the mechanisms underlying feeding state-dependent behavioral changes remain undefined. Previous studies have shown that Caenorhabditis elegans hermaphrodite exhibits avoidance behaviors to acute exposure of a pheromone, ascr#3 (asc-ΔC9, C9). Here, we show that the ascr#3 avoidance behavior is modulated by feeding state via the insulin signaling pathway. Starvation increases ascr#3 avoidance behavior, and loss-of-function mutations in daf-2 insulin-like receptor gene dampen this starvation-induced ascr#3 avoidance behavior. DAF-2 and its downstream signaling molecules, including the DAF-16 FOXO transcription factor, act in the ascr#3-sensing ADL neurons to regulate synaptic transmission to downstream target neurons, including the AVA command interneurons. Moreover, we found that starvation decreases the secretion of INS-18 insulin-like peptides from the intestine, which antagonizes DAF-2 function in the ADL neurons. Altogether, this study provides insights about the molecular communication between intestine and sensory neurons delivering hunger message to sensory neurons, which regulates avoidance behavior from pheromones to facilitate survival chance.
Assuntos
Aprendizagem da Esquiva/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Insulina/metabolismo , Receptor de Insulina/metabolismo , Inanição/metabolismo , Transmissão Sináptica/fisiologia , Animais , Proteínas de Caenorhabditis elegans/genética , Fatores de Transcrição Forkhead/genética , Neurônios/metabolismo , Hormônios Peptídicos/metabolismo , Feromônios/metabolismo , Receptor de Insulina/genética , Transdução de Sinais , Transmissão Sináptica/genéticaRESUMO
Animal locomotion is mediated by a sensory system referred to as proprioception. Defects in the proprioceptive coordination of locomotion result in uncontrolled and inefficient movements. However, the molecular mechanisms underlying proprioception are not fully understood. Here, we identify two transient receptor potential cation (TRPC) channels, trp-1 and trp-2, as necessary and sufficient for proprioceptive responses in C. elegans head steering locomotion. Both channels are expressed in the SMDD neurons, which are required and sufficient for head bending, and mediate coordinated head steering by sensing mechanical stretches due to the contraction of head muscle and orchestrating dorsal head muscle contractions. Moreover, the SMDD neurons play dual roles to sense muscle stretch as well as to control muscle contractions. These results demonstrate that distinct locomotion patterns require dynamic and homeostatic modulation of feedback signals between neurons and muscles.
Assuntos
Caenorhabditis elegans/fisiologia , Mecanorreceptores/fisiologia , Neurônios Motores/fisiologia , Propriocepção/fisiologia , Células Receptoras Sensoriais/fisiologia , Canais de Cátion TRPC/fisiologia , Animais , Caenorhabditis elegans/genética , Locomoção/fisiologia , Canais de Cátion TRPC/genéticaRESUMO
Proneural genes are among the most early-acting genes in nervous system development, instructing blast cells to commit to a neuronal fate. Drosophila Atonal and Achaete-Scute complex (AS-C) genes, as well as their vertebrate orthologs, are basic helix-loop-helix (bHLH) transcription factors with such proneural activity. We show here that a C. elegans AS-C homolog, hlh-4, functions in a fundamentally different manner. In the embryonic, larval, and adult nervous systems, hlh-4 is expressed exclusively in a single nociceptive neuron class, ADL, and its expression in ADL is maintained via transcriptional autoregulation throughout the life of the animal. However, in hlh-4 null mutants, the ADL neuron is generated and still appears neuronal in overall morphology and expression of panneuronal and pansensory features. Rather than acting as a proneural gene, we find that hlh-4 is required for the ADL neuron to function properly, to adopt its correct morphology, to express its unusually large repertoire of olfactory receptor-encoding genes, and to express other known features of terminal ADL identity, including neurotransmitter phenotype, neuropeptides, ion channels, and electrical synapse proteins. hlh-4 is sufficient to induce ADL identity features upon ectopic expression in other neuron types. The expression of ADL terminal identity features is directly controlled by HLH-4 via a phylogenetically conserved E-box motif, which, through bioinformatic analysis, we find to constitute a predictive feature of ADL-expressed terminal identity markers. The lineage that produces the ADL neuron was previously shown to require the conventional, transient proneural activity of another AS-C homolog, hlh-14, demonstrating sequential activities of distinct AS-C-type bHLH genes in neuronal specification. Taken together, we have defined here an unconventional function of an AS-C-type bHLH gene as a terminal selector of neuronal identity and we speculate that such function could be reflective of an ancestral function of an "ur-" bHLH gene.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Regulação da Expressão Gênica no Desenvolvimento , Nociceptores/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Caenorhabditis elegans/citologia , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Biologia Computacional , Sinapses Elétricas/metabolismo , Sinapses Elétricas/ultraestrutura , Embrião não Mamífero , Ontologia Genética , Canais Iônicos/genética , Canais Iônicos/metabolismo , Larva/citologia , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Anotação de Sequência Molecular , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Neurotransmissores/metabolismo , Nociceptores/citologia , Fenótipo , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Transcrição GênicaRESUMO
Experiences during early development can influence neuronal functions and modulate adult behaviors [1, 2]. However, the molecular mechanisms underlying the long-term behavioral effects of these early experiences are not fully understood. The C. elegans ascr#3 (asc-ΔC9; C9) pheromone triggers avoidance behavior in adult hermaphrodites [3-7]. Here, we show that hermaphrodites that are briefly exposed to ascr#3 immediately after birth exhibit increased ascr#3-specific avoidance as adults, indicating that ascr#3-experienced animals form a long-lasting memory or imprint of this early ascr#3 exposure [8]. ascr#3 imprinting is mediated by increased synaptic activity between the ascr#3-sensing ADL neurons and their post-synaptic SMB motor neuron partners via increased expression of the odr-2 glycosylated phosphatidylinositol (GPI)-linked signaling gene in the SMB neurons. Our study suggests that the memory for early ascr#3 experience is imprinted via alteration of activity of a single synaptic connection, which in turn shapes experience-dependent plasticity in adult ascr#3 responses.
Assuntos
Caenorhabditis elegans/fisiologia , Memória , Feromônios/fisiologia , Células Receptoras Sensoriais/fisiologia , Animais , Aprendizagem da Esquiva , Organismos Hermafroditas/fisiologia , Transdução de SinaisRESUMO
In this study, we used spectrally focused coherent anti-Stokes Raman scattering (spCARS) microscopy assisted by sum-frequency generation (SFG) to monitor the variations in the structural morphology and molecular vibrations of a live muscle of Caenorhabditis elegans. The subunits of the muscle sarcomeres, such as the M-line, myosin, dense body, and α-actinin, were alternatively observed using spCARS microscopy for different sample orientations, with the guidance of a myosin positional marker captured by SFG microscopy. Interestingly enough, the beam polarization dependence of the spCARS contrasts for two parallel subunits (dense body and myosin) showed a ~90° phase difference. The chemically sensitive spCARS spectra induced by the time-varying overlap of two pulses allowed (after a robust subtraction of the non-resonant background using a modified Kramers-Krönig transformation method) high-fidelity detection of various genetically modified muscle sarcomeres tuned to the C-H vibration (2800-3100 cm-1). Conversely, SFG image mapping assisted by phase-retrieved spCARS spectra also facilitated label-free monitoring of the changes in the muscle content of C. elegans that are associated with aging, based on the hypothesis that the C-H vibrational modes could serve as qualitative chemical markers sensitive to the amount and/or structural modulation of the muscle.
Assuntos
Microscopia , Sarcômeros/química , Sarcômeros/metabolismo , Análise Espectral Raman , Animais , Caenorhabditis elegansRESUMO
Environmental stress during early development can impact adult phenotypes via programmed changes in gene expression. C. elegans larvae respond to environmental stress by entering the stress-resistant dauer diapause pathway and resume development once conditions improve (postdauers). Here we show that the osm-9 TRPV channel gene is a target of developmental programming and is down-regulated specifically in the ADL chemosensory neurons of postdauer adults, resulting in a corresponding altered olfactory behavior that is mediated by ADL in an OSM-9-dependent manner. We identify a cis-acting motif bound by the DAF-3 SMAD and ZFP-1 (AF10) proteins that is necessary for the differential regulation of osm-9, and demonstrate that both chromatin remodeling and endo-siRNA pathways are major contributors to the transcriptional silencing of the osm-9 locus. This work describes an elegant mechanism by which developmental experience influences adult phenotypes by establishing and maintaining transcriptional changes via RNAi and chromatin remodeling pathways.
Assuntos
Comportamento Animal , Caenorhabditis elegans/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Sistema Límbico/embriologia , Percepção Olfatória , Interferência de RNA , Olfato , Animais , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Canais de Cátion TRPV/metabolismoRESUMO
Environmental fluctuations influence organismal aging by affecting various regulatory systems. One such system involves sensory neurons, which affect life span in many species. However, how sensory neurons coordinate organismal aging in response to changes in environmental signals remains elusive. Here, we found that a subset of sensory neurons shortens Caenorhabditis elegans' life span by differentially regulating the expression of a specific insulin-like peptide (ILP), INS-6. Notably, treatment with food-derived cues or optogenetic activation of sensory neurons significantly increases ins-6 expression and decreases life span. INS-6 in turn relays the longevity signals to nonneuronal tissues by decreasing the activity of the transcription factor DAF-16/FOXO. Together, our study delineates a mechanism through which environmental sensory cues regulate aging rates by modulating the activities of specific sensory neurons and ILPs.
Assuntos
Proteínas de Caenorhabditis elegans/genética , Alimentos , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica , Insulina/genética , Longevidade/genética , Hormônios Peptídicos/genética , Proteínas de Caenorhabditis elegans/metabolismo , Sinais (Psicologia) , Meio Ambiente , Fatores de Transcrição Forkhead/metabolismo , Insulina/metabolismo , Optogenética , Hormônios Peptídicos/metabolismo , Células Receptoras Sensoriais/fisiologia , Transdução de SinaisRESUMO
Animals must constantly assess their surroundings and integrate sensory cues to make appropriate behavioral and developmental decisions. Pheromones produced by conspecific individuals provide critical information regarding environmental conditions. Ascaroside pheromone concentration and composition are instructive in the decision of Caenorhabditis elegans to either develop into a reproductive adult or enter into the stress-resistant alternate dauer developmental stage. Pheromones are sensed by a small set of sensory neurons, and integrated with additional environmental cues, to regulate neuroendocrine signaling and dauer formation. To identify molecules required for pheromone-induced dauer formation, we performed an unbiased forward genetic screen and identified phd (pheromone response-defective dauer) mutants. Here, we describe new roles in dauer formation for previously identified neuronal molecules such as the WD40 domain protein QUI-1 and MACO-1 Macoilin, report new roles for nociceptive neurons in modulating pheromone-induced dauer formation, and identify tau tubulin kinases as new genes involved in dauer formation. Thus, phd mutants define loci required for the detection, transmission, or integration of pheromone signals in the regulation of dauer formation.