RESUMO
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.
Assuntos
Caenorhabditis elegans , Gotículas Lipídicas , Pseudomonas aeruginosa , Humanos , Gotículas Lipídicas/metabolismo , Animais , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Células HEK293 , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/genética , Relógios Biológicos/genética , Evolução Biológica , Metabolismo dos Lipídeos/genética , Ritmo Circadiano/genética , Ritmo Circadiano/fisiologiaRESUMO
Macauba (Acrocomia aculeata) is a Brazilian palm tree whose oil in the pulp is rich in oleic acid and carotenoids. However, its physiological function remains unknown. This study aimed to investigate the effects of macauba pulp oil (MPO) on the metabolic link between lipid metabolism and lifespan using Caenorhabditis elegans (C. elegans). C. elegans were treated with 5.0 mg/mL of MPO for analyzing triglyceride and glycerol accumulation, fatty acid profile, gene expression of lipid and oxidative metabolism proteins under cold (4°C) stress conditions, and lifespan analysis under stress conditions such as cold (4°C), heat (37°C), and oxidative (paraquat) stress. MPO significantly suppressed fat accumulation and increased glycerol (a lipolysis index) and the lifespan of C. elegans at low temperature (4°C). This was accompanied by decreased mRNA levels of the genes involved in lipogenesis (spb-1 and pod-2) and increased levels of the genes involved in fatty acid ß-oxidation (acs-2 and nhr-49) and fat mobilization genes (hosl-1 and aak-2). Additionally, MPO treatment modulated fatty acid pools in C. elegans at low temperatures in that MPO treatment decreased saturated fatty acid levels and shifted the fatty acid profile to long-chain fatty acids. Moreover, the effect of MPO on fat accumulation at low temperatures was abolished in fat-7 mutants, whereas both fat-1 and fat-7 contribute, at least in part, to MPO-elevated survival of C. elegans under cold conditions. PRACTICAL APPLICATION: The results obtained in the present study may contribute to the understanding of the health benefits of consuming macauba pulp oil and consequently stimulate economic growth and the industrial application of this new type of oil, which may result in the creation of new jobs and increased value of small producers.
Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Temperatura Baixa , Metabolismo dos Lipídeos , Longevidade , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Longevidade/efeitos dos fármacos , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Metabolismo dos Lipídeos/efeitos dos fármacos , Óleos de Plantas/farmacologia , Arecaceae/química , Ácidos Graxos/metabolismo , Triglicerídeos/metabolismo , Glicerol/metabolismo , Glicerol/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Óleo de Palmeira/farmacologiaRESUMO
Circadian rhythms are endogenous oscillations in nearly all organisms, from prokaryotes to humans, allowing them to adapt to cyclical environments for close to 24 h. Circadian rhythms are regulated by a central clock, based on a transcription-translation feedback loop. One important protein in the central loop in metazoan clocks is PERIOD, which is regulated in part by Casein kinase 1ε/δ (CK1ε/δ) phosphorylation. In the nematode Caenorhabditis elegans, period and casein kinase 1ε/δ are conserved as lin-42 and kin-20, respectively. Here, we studied the involvement of lin-42 and kin-20 in the circadian rhythms of the adult nematode using a bioluminescence-based circadian transcriptional reporter. We show that mutations of lin-42 and kin-20 generate a significantly longer endogenous period, suggesting a role for both genes in the nematode circadian clock, as in other organisms. These phenotypes can be partially rescued by overexpression of either gene under their native promoter. Both proteins are expressed in neurons and epidermal seam cells, as well as in other cells. Depletion of LIN-42 and KIN-20, specifically in neuronal cells after development, was sufficient to lengthen the period of oscillating sur-5 expression. Therefore, we conclude that LIN-42 and KIN-20 are critical regulators of the adult nematode circadian clock through neuronal cells.
Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Ritmo Circadiano , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Relógios Circadianos/genética , Ritmo Circadiano/genética , Proteínas CLOCK/genética , Proteínas CLOCK/metabolismo , Regulação da Expressão Gênica , Mutação , Neurônios/metabolismo , Fatores de TranscriçãoRESUMO
Cellular response to redox imbalance is crucial for organismal health. microRNAs are implicated in stress responses. ALG-1, the C. elegans ortholog of human AGO2, plays an essential role in microRNA processing and function. Here we investigated the mechanisms governing ALG-1 expression in C. elegans and the players controlling lifespan and stress resistance downstream of ALG-1. We show that upregulation of ALG-1 is a shared feature in conditions linked to increased longevity (e.g., germline-deficient glp-1 mutants). ALG-1 knockdown reduces lifespan and oxidative stress resistance, while overexpression enhances survival against pro-oxidant agents but not heat or reductive stress. R02D3.7 represses alg-1 expression, impacting oxidative stress resistance at least in part via ALG-1. microRNAs upregulated in glp-1 mutants (miR-87-3p, miR-230-3p, and miR-235-3p) can target genes in the protein disulfide isomerase pathway and protect against oxidative stress. This study unveils a tightly regulated network involving transcription factors and microRNAs which controls organisms' ability to withstand oxidative stress.
Assuntos
Proteínas de Caenorhabditis elegans , MicroRNAs , Animais , Humanos , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Estresse Oxidativo/genética , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismoRESUMO
Intertissue RNA transport recently emerged as a novel signaling mechanism. In mammals, mounting evidence suggests that small RNA transfer between cells is widespread and used in various physiological contexts. In the nematode C. elegans, a similar mechanism is conferred by the systemic RNAi pathway. Members of the Systemic RNA Interference Defective (SID) family act at different steps of cellular RNA uptake and export. The limiting step in systemic RNA interference (RNAi) is the import of extracellular RNAs via the conserved double-stranded (dsRNA)-gated dsRNA channel SID-1. To better understand the role of RNAs as intertissue signaling molecules, we modified the function of SID-1 in specific tissues of C. elegans. We observed that sid-1 loss-of-function mutants are as healthy as wild-type worms. Conversely, overexpression of sid-1 in C. elegans intestine, muscle, or neurons rendered worms short-lived. The effects of intestinal sid-1 overexpression were attenuated by silencing the components of systemic RNAi sid-1, sid-2 and sid-5, implicating systemic RNA signaling in the lifespan reduction. Accordingly, tissue-specific overexpression of sid-2 and sid-5 also reduced worm lifespan. Additionally, an RNAi screen for components of several non-coding RNA pathways revealed that silencing the miRNA biogenesis proteins PASH-1 and DCR-1 rendered the lifespan of worms with intestinal sid-1 overexpression similar to controls. Collectively, our data support the notion that systemic RNA signaling must be tightly regulated, and unbalancing that process provokes a reduction in lifespan. We termed this phenomenon Intercellular/Extracellular Systemic RNA imbalance (InExS).
Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Interferência de RNA , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Longevidade/genética , RNA de Cadeia Dupla/metabolismo , Proteínas de Membrana/genética , Mamíferos/genéticaRESUMO
Bladder cancer is the fourth most common malignancy in men. It can present along the entire continuum of severity, from mild to well-differentiated disease to extremely malignant tumors with low survival rates. Human RAS genes are the most frequently mutated oncogenes in human cancers, and the critical role of aberrant Ras protein function in carcinogenesis is well established. Therefore, considerable efforts have been devoted to the development of anti-Ras inhibitors for cancer treatment. This study presents the biphenyl dihydropyrimidinone LaSOM 335 with high activity against T24 bladder cancer cells (IC50 = 10.73 ± 0.53 µM) and selectivity of cytotoxicity for this cancer cell line compared to two non-cancer cell lines investigated. Furthermore, we also show that this compound reduced vulvar development in the mutant let-60 gene of Caenorhabditis elegans. Let-60 is a homolog of the mammalian Ras gene. In addition, we observed that LaSOM 335 inhibits the enzymatic activity of CD73 and decreases CD73 expression. Possibly, this expression decrease is due to downstream EGFR signaling via the Ras-Raf-ERK pathway, that directly regulates CD73 expression via ERK1/2. Evidence suggests that non-immunomodulating functions of CD73 play an equally important role for cancer cell survival, progression, and migration. Regarding we also notice that LaSOM 335 was safe in the in vivo model of C. elegans. The set of these findings makes this biphenyl dihydropyrimidinone a promising candidate for further investigations in the bladder cancer field.
Assuntos
Genes ras , Neoplasias da Bexiga Urinária , Masculino , Animais , Humanos , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Linhagem Celular Tumoral , Neoplasias da Bexiga Urinária/tratamento farmacológico , Neoplasias da Bexiga Urinária/metabolismo , 5'-Nucleotidase/genética , 5'-Nucleotidase/metabolismo , Mamíferos/genética , Mamíferos/metabolismoRESUMO
Caenorhabditis elegans can enter a diapause stage called "dauer" when it senses that the environment is not suitable for development. This implies a detour from the typical developmental trajectory and requires a tight control of the developmental clock and a massive tissue remodeling. In the last decades, core components of the signaling pathways that govern the dauer development decision have been identified, but the tissues where they function for the acquisition of dauer-specific traits are still under intense study. Growing evidence demonstrates that these pathways engage in complex cross-talk and feedback loops. In this review, we summarize the current knowledge regarding the transcriptional regulation of the dauer program and the relevant tissues for its achievement. A better understanding of this process will provide insight on how developmental plasticity is achieved and how development decisions are under a robust regulation to ensure an all-or-nothing response. Furthermore, this developmental decision can also serve as a simplified model for relevant developmental disorders.Abbreviations: AID Auxin Induced Degron DA dafachronic acid Daf-c dauer formation constitutive Daf-d dauer formation defective DTC Distal Tip Cells ECM modified extracellular matrix GPCRs G protein-coupled receptors IIS insulin/IGF-1 signaling ILPs insulin-like peptides LBD Ligand Binding Domain PDL4 Post Dauer L4 TGF-ß transforming growth factor beta WT wild-type.
Assuntos
Proteínas de Caenorhabditis elegans , Animais , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Transdução de Sinais , Regulação da Expressão Gênica , Insulina/metabolismoRESUMO
Circadian rhythms represent an adaptive feature, ubiquitously found in nature, which grants living beings the ability to anticipate daily variations in their environment. They have been found in a multitude of organisms, ranging from bacteria to fungi, plants, and animals. Circadian rhythms are generated by endogenous clocks that can be entrained daily by environmental cycles such as light and temperature. The molecular machinery of circadian clocks includes a transcriptional-translational feedback loop that takes approximately 24 h to complete. Drosophila melanogaster has been a model organism of choice to understand the molecular basis of circadian clocks. However, alternative animal models are also being adopted, each offering their respective experimental advantages. The nematode Caenorhabditis elegans provides an excellent model for genetics and neuro-behavioral studies, which thanks to its ease of use and manipulation, as well as availability of genetic data and mutant strains, is currently used as a novel model for circadian research. Here, we aim to evaluate C. elegans as a model for chronobiological studies, focusing on its strengths and weaknesses while reviewing the available literature. Possible zeitgebers (including light and temperature) are also discussed. Determining the molecular bases and the neural circuitry involved in the central pacemaker of the C. elegans' clock will contribute to the understanding of its circadian system, becoming a novel model organism for the study of diseases due to alterations of the circadian cycle.
Assuntos
Relógios Circadianos , Ritmo Circadiano , Animais , Ritmo Circadiano/genética , Caenorhabditis elegans/genética , Drosophila melanogaster/genética , Relógios Circadianos/genética , TemperaturaRESUMO
The nematode Caenorhabditis elegans requires exogenous cholesterol to survive and its depletion leads to early developmental arrest. Thus, tight regulation of cholesterol storage and distribution within the organism is critical. Previously, we demonstrated that the endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) plays a key role in C. elegans since it modulates sterol mobilization. However, the mechanism remains unknown. Here we show that mutations in the ocr-2 and osm-9 genes, coding for transient receptors potential V (TRPV) ion channels, dramatically reduce the effect of 2-AG in cholesterol mobilization. Through genetic analysis in combination with the rescue of larval arrest induced by sterol starvation, we found that the insulin/IGF-1signaling (IIS) pathway and UNC-31/CAPS, a calcium-activated regulator of neural dense-core vesicles release, are essential for 2-AG-mediated stimulation of cholesterol mobilization. These findings indicate that 2-AG-dependent cholesterol trafficking requires the release of insulin peptides and signaling through the DAF-2 insulin receptor. These results suggest that 2-AG acts as an endogenous modulator of TRPV signal transduction to control intracellular sterol trafficking through modulation of the IGF-1 signaling pathway.
Assuntos
Caenorhabditis elegans , Canabinoides , Animais , Caenorhabditis elegans/genética , Colesterol/genética , Esteróis , InsulinaRESUMO
Caenorhabditis elegans is a free-living nematode, belonging to the bacterivorous trophic group. Although it was cited in several countries, in different types of ecosystems and in associations with other organisms, the wild habitats of this nematode have not yet been precisely defined. In Argentina, C. elegans was recently isolated from the hoverfly Allograpta exotica, a voracious predator with potential biological control against aphids in horticultural crops. In this frame, the objectives of this study were (i) to characterize it molecularly and morphologically (ii) to report a wild strain of C. elegans for the first time from Argentina, (iii) to present a new ecological niche by associating it with A. exotica and (iv) to evaluate the pathogenicity against these insects. The results of the morphological and molecular analyses made it possible to determine that the isolated nematode was C. elegans, thus establishing the ARGLP1900 wild strain as the first record of this nematode for Argentina. A new association was described, since there are no records of interaction between C. elegans and A. exotica, providing information on a new ecological niche. The new wild strain found in this work, could be appropriate for comparative genomic studies with other C. elegans strains.