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Intermittent fasting remains a safe and effective strategy to ameliorate various age-related diseases, but its specific mechanisms are not fully understood. Considering that transcription factors (TFs) determine the response to environmental signals, here, we profiled the diurnal expression of 600 samples across four metabolic tissues sampled every 4 over 24 h from mice placed on five different feeding regimens to provide an atlas of TFs in biological space, time, and feeding regimen. Results showed that 1218 TFs exhibited tissue-specific and temporal expression profiles in ad libitum mice, of which 974 displayed significant oscillations at least in one tissue. Intermittent fasting triggered more than 90% (1161 in 1234) of TFs to oscillate somewhere in the body and repartitioned their tissue-specific expression. A single round of fasting generally promoted TF expression, especially in skeletal muscle and adipose tissues, while intermittent fasting mainly suppressed TF expression. Intermittent fasting down-regulated aging pathway and upregulated the pathway responsible for the inhibition of mammalian target of rapamycin (mTOR). Intermittent fasting shifts the diurnal transcriptome atlas of TFs, and mTOR inhibition may orchestrate intermittent fasting-induced health improvements. This atlas offers a reference and resource to understand how TFs and intermittent fasting may contribute to diurnal rhythm oscillation and bring about specific health benefits.
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The venom of Lycosoidea spiders is a complex multicomponent mixture of neurotoxic peptides (main components) and antimicrobial peptides (AMPs) as minor components. In this study, we described the high-throughput identification and analysis of AMPs from Lycosa sinensis venom (named LS-AMPs) using a combination strategy that includes the following three different analysis approaches: (i) peptidomic analysis, namely reversed-phase high-performance liquid chromatography (RP-HPLC) separation plus top-down sequencing by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS); (ii) transcriptomic analysis, namely cDNA library construction plus DNA sequencing; (iii) bioinformatic analysis, namely analysis and prediction for molecular characters of LS-AMPs by the online biology databases. In total, 52 sequences of AMPs were identified from L. sinensis venom, and all AMPs can be categorized into eight different families according to phylogenetic analysis and sequence identity. This is the largest number of AMPs identified from a spider species so far. In the present study, we demonstrated molecular characteristics, such as complex precursor, N- and/or C-terminally truncated analogs, and C-terminal amidation of LS-AMPs from L. sinensis venom. This is a preliminary investigation on the molecular diversification of venom-derived AMPs from the wolf spider species (family Lycosidae), and a detailed investigation on the functional diversity of LS-AMPs will be preformed in the future.
Assuntos
Peptídeos/análise , Proteínas Citotóxicas Formadoras de Poros/química , Proteínas Citotóxicas Formadoras de Poros/genética , Venenos de Aranha/química , Venenos de Aranha/genética , Aranhas/metabolismo , Sequência de Aminoácidos , Animais , Cromatografia de Fase Reversa , Biologia Computacional , Feminino , Perfilação da Expressão Gênica , Biblioteca Gênica , Peptídeos/química , Peptídeos/genética , Filogenia , Proteômica , Alinhamento de Sequência , Análise de Sequência de DNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Spider venoms are insecticidal mixtures with diverse biological activities, and acylpolyamines are their small molecular active components. However, the mechanism for the insecticidal activity of acylpolyamines remains to be elucidated. Here, the structure and function of two acylpolyamine toxins, AVTX-622 and AVTX-636, from Araneus ventricosus were investigated. Nuclear magnetic resonance (NMR) analysis illustrated that the structure of two toxins was very similar, and compared to AVTX-636, AVTX-622 only missed a methylene group in the linker region between the polyamine head and tail. Both the two toxins did not inhibit on voltage-gated sodium channels in mammalian neuronal cells. Intriguingly, AVTX-622, but not AVTX-636, inhibited voltage-gated sodium channels in DUM neuronal cells of Periplaneta americana. Further animal test displayed that the paralyzing potency of AVTX-622 on insect was over ten-times stronger than that of AVTX-636. These findings indicate that a single methylene deletion from AVTX-636 offered AVTX-622 the insect-selective voltage-gated sodium channel activity, which not only elucidated structure-function of the toxins, but also provided new clues for insect-selective insecticide design.
Assuntos
Poliaminas/farmacologia , Venenos de Aranha/farmacologia , Canais de Sódio Disparados por Voltagem/metabolismo , Animais , Células Cultivadas , Estrutura Molecular , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ressonância Magnética Nuclear Biomolecular , Poliaminas/química , Ratos , Ratos Sprague-Dawley , Venenos de Aranha/química , AranhasRESUMO
Toxoplasmosis is a widely distributed parasitic protozoan disease, caused by Toxoplasma gondii (T. gondii). High prevalence of toxoplasmosis and limitations of conventional treatments lead to a search for new therapeutic drugs. Lycosin-I is a linear peptide, derived from the venom of the spider Lycosa singoriensis. The aim of the present study was to determine the anti-parasitic effect of lycosin-Ι against T. gondii. In vitro, the anti-T. gondii activities of lycosin-Ι were evaluated by MTT assay, trypan blue exclusion assay, cell counting assay and plaque assay. Cytokines of IL-6 and IL-8 were measured by quantitative PCR. In addition, the structures of tachyzoites treated with lycosin-Ι were also observed by scanning and transmission electron microscopy. In vivo, mice were challenged with parasites treated by lycosin-I. The results revealed that lycosin-Ι had shown a significant ability to inhibit T. gondii invasion and proliferation. Cytokines of IL-6 and IL-8 were reduced by lycosin-Ι at transcription level in human foreskin fibroblast (HFF) cells infected with T. gondii tachyzoites, but they were increased compared to non-infected cells. For tachyzoites, lycosin-Ι induced their cell membrane alterations with formation of invaginations, some of them appeared to be vacuolated in their cytoplasm. Moreover, lycosin-Ι had prolonged the survival time of mice by controlling T. gondii proliferation. In conclusion, our present study provides the first evidence for anti-T. gondii by using the spider peptide lycosin-Ι. These findings suggest that lycosin-Ι is a potential alternative agent for the treatment of toxoplasmosis.
Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Coccidiostáticos/farmacologia , Venenos de Aranha/farmacologia , Toxoplasma/efeitos dos fármacos , Animais , Peptídeos Catiônicos Antimicrobianos/química , Contagem de Células , Membrana Celular/efeitos dos fármacos , Células Cultivadas , Coccidiostáticos/química , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/parasitologia , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Interleucina-8/genética , Interleucina-8/metabolismo , Masculino , Camundongos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Reação em Cadeia da Polimerase em Tempo Real , Venenos de Aranha/química , Sais de Tetrazólio , Tiazóis , Toxoplasma/imunologia , Toxoplasma/ultraestrutura , Azul TripanoRESUMO
OBJECTIVE: The peptide lycosin-I has anti-bacterial and anti-cancer capacities. However, the anti-inflammatory activity of lycosin-I remains unknown. We investigated whether lycosin-I could attenuate inflammation. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVECs) were treated with lycosin-I before exposure to tumor necrosis factor-α (TNF-α). The expression of intercellular cell adhesion molecule-1 (ICAM-1), nuclear transcription factor-kappa B (NF-κB) p65 and inhibitory subunit of NF-κB alpha (IκBα) was evaluated by western blot. The expression of interleukin-6 (IL-6) and interleukin-8 (IL-8) was detected by quantitative RT-PCR or ELISA. Immunofluorescence analysis was used to determine the impact of lycosin-I on NF-κB pathway. C57BL/6 mice were pretreated with lycosin-I before exposure with lipopolysaccharide (LPS). RESULTS: Lycosin-I significantly reduced the TNF-α-enhanced expression of IL-6, IL-8 and ICAM-1. Lycosin-I also inhibited the human monocyte cells adhesion to HUVECs. We further demonstrated that lycosin-I could effectively suppress the reaction of endothelial cells to TNF-α by inhibiting IκBα degradation. Subsequently, the phosphorylation and translocation of NF-κB p65 could also be attenuated. Furthermore, lycosin-I exhibited a significant protection of C57BL/6 mice against LPS-induced death. CONCLUSIONS: Our results suggested that the anti-inflammatory activity of lycosin-I was associated with NF-κB activation and lycosin-I had potential to be a novel therapeutic candidate for inflammatory diseases.
Assuntos
Anti-Inflamatórios/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Quinase I-kappa B/antagonistas & inibidores , Inflamação/prevenção & controle , NF-kappa B/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Venenos de Aranha/farmacologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Animais , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Quinase I-kappa B/biossíntese , Inflamação/induzido quimicamente , Inflamação/mortalidade , Molécula 1 de Adesão Intercelular/biossíntese , Lipopolissacarídeos/antagonistas & inibidores , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/biossíntese , Fator de Transcrição RelA/antagonistas & inibidores , Fator de Transcrição RelA/biossínteseRESUMO
To investigate biochemical mechanisms for the tetracycline-induced steatosis in rats, targeted proteins of oxidative modification were profiled. The results showed that tetracycline induced lipid accumulation, oxidative stress, and cell viability decline in HepG2 cells only under the circumstances of palmitic acid overload. Tetracycline administration in rats led to significant decrement in blood lipids, while resulted in more than four times increment in intrahepatic triacylglycerol and typical microvesicular steatosis in the livers. The triacylglycerol levels were positively correlated with oxidative stress. Proteomic profiles of carbonylated proteins revealed 26 targeted proteins susceptible to oxidative modification and most of them located in mitochondria. Among them, the long-chain specific acyl-CoA dehydrogenase was one of the key enzymes regulating fatty acid ß-oxidation. Oxidative modification of the enzyme in the tetracycline group depressed its enzymatic activity. In conclusion, the increased influx of lipid into the livers is the first hit of tetracycline-induced microvesicular steatosis. Oxidative stress is an essential part of the second hit, which may arise from the lipid overload and attack a series of functional proteins, aggravating the development of steatosis. The 26 targeted proteins revealed here provide a potential direct link between oxidative stress and tetracycline-induced steatosis.
Assuntos
Antibacterianos , Fígado Gorduroso/induzido quimicamente , Fígado Gorduroso/metabolismo , Fígado/patologia , Carbonilação Proteica , Proteínas/metabolismo , Tetraciclina , Animais , Ácidos Graxos/metabolismo , Fígado Gorduroso/patologia , Células Hep G2 , Humanos , Fígado/metabolismo , Masculino , Mapas de Interação de Proteínas , Proteínas/análise , Proteômica , Ratos , Ratos Sprague-DawleyRESUMO
BACKGROUND: Black widow spider (L. tredecimguttatus) has toxic components not only in the venomous glands, but also in other parts of the body and its eggs. It is biologically important to investigate the molecular basis of the egg toxicity. RESULTS: In the present work, an aqueous extract was prepared from the eggs of the spider and characterized using multiple physiological and biochemical strategies. Gel electrophoresis and mass spectrometry demonstrated that the eggs are rich in high-molecular-mass proteins and the peptides below 5 kDa. The lyophilized extract of the eggs had a protein content of 34.22% and was shown to have a strong toxicity towards mammals and insects. When applied at a concentration of 0.25 mg/mL, the extract could completely block the neuromuscular transmission in mouse isolated phrenic nerve-hemidiaphragm preparations within 12.0 ± 1.5 min. Using whole-cell patch-clamp technique, the egg extract was demonstrated to be able to inhibit the voltage-activated Na+, K+ and Ca2+ currents in rat DRG neurons. In addition, the extract displayed activities of multiple hydrolases. Finally, the molecular basis of the egg toxicity was discussed. CONCLUSIONS: The eggs of black widow spiders are rich in proteinous compounds particularly the high-molecular-mass proteins with different types of biological activity The neurotoxic and other active compounds in the eggs are believed to play important roles in the eggs' toxic actions.
Assuntos
Proteínas de Artrópodes/toxicidade , Viúva Negra/química , Óvulo/química , Extratos de Tecidos/química , Exoesqueleto/química , Exoesqueleto/fisiologia , Animais , Proteínas de Artrópodes/isolamento & purificação , Canais de Cálcio/efeitos dos fármacos , Baratas/efeitos dos fármacos , Gânglios Espinais/efeitos dos fármacos , Camundongos , Óvulo/fisiologia , Nervo Frênico/efeitos dos fármacos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos dos fármacos , Ratos , Extratos de Tecidos/toxicidade , Canais de Sódio Disparados por Voltagem/efeitos dos fármacosRESUMO
PURPOSE: While reactive oxygen species (ROS) have been identified as key redox signaling agents contributing to aging process, which and how specific oxidants trigger healthy longevity remain unclear. This paper aimed to explore the precise role and signaling mechanism of superoxide (O2â¢-) in health and longevity. METHODS: A tool for precise regulation of O2â¢- levels in vivo was developed based on the inhibition of superoxide dismutase 1 (SOD1) by tetrathiomolybdate (TM) in Caenorhabditis elegans (C. elegans). Then, we examined the effects of TM on lifespan, reproduction, lipofuscin accumulation, mobility, and stress resistance. Finally, the signaling mechanism for longevity induced by TM-O2â¢- was screened by transcriptome analysis and tested in sod-1 and argk-1 RNAi strains, sod-2, sod-3, and daf-16 mutants. RESULTS: TM promoted longevity in C. elegans with a concomitant extension of healthy lifespan as indicated by increasing fertility and mobility and reducing lipofuscin accumulation, as well as enhanced resistance to different abiotic stresses. Mechanically, TM could precisely regulate O2â¢- levels in nematodes via modulating SOD1 activity. An O2â¢- scavenger Mn(III)TBAP abolished TM-induced lifespan extension, while an O2â¢- generator paraquat at low concentration mimicked the life prolongation effects. The longevity in TM-treated worms was abolished by sod-1 RNAi but was not affected in sod-2 or sod-3 mutants. Further transcriptome analysis revealed arginine kinase ARGK-1 and its downstream insulin/insulin-like growth factor 1 signaling (IIS) as potential effectors for TM-O2â¢â¾-induced longevity, and argk-1 RNAi or daf-16 mutant nullified the longevity. CONCLUSIONS: These findings indicate that it is feasible to precisely control specific oxidant in vivo and O2â¢- orchestrates TM-induced health and longevity in C. elegans via ARGK-1-IIS axis.
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Aims: Redox signaling plays a key role in skeletal muscle remodeling induced by exercise and prolonged inactivity, but it is unclear which oxidant triggers myofiber hypertrophy due to the lack of strategies to precisely regulate individual oxidants in vivo. In this study, we used tetrathiomolybdate (TM) to dissociate the link between superoxide (O2â¢-) and hydrogen peroxide and thereby to specifically explore the role of O2â¢- in muscle hypertrophy in C2C12 cells and mice. Results: TM can linearly regulate intracellular O2â¢- levels by inhibition of superoxide dismutase 1 (SOD1). A 70% increase in O2â¢- levels in C2C12 myoblast cells and mice is necessary and sufficient for triggering hypertrophy of differentiated myotubes and can enhance exercise performance by more than 50% in mice. SOD1 knockout blocks TM-induced O2â¢- increments and thereby prevents hypertrophy, whereas SOD1 restoration rescues all these effects. Scavenging O2â¢- with antioxidants abolishes TM-induced hypertrophy and the enhancement of exercise performance, whereas the restoration of O2â¢- levels with a O2â¢- generator promotes muscle hypertrophy independent of SOD1 activity. Innovation and Conclusion: These findings suggest that O2â¢- is an endogenous initiator of myofiber hypertrophy and that TM may be used to treat muscle wasting diseases. Our work not only suggests a novel druggable mechanism to increase muscle mass but also provides a tool for precisely regulating O2â¢- levels in vivo.
RESUMO
To screen target proteins of oxidative stress which mediate the effects of exercise on preventing nonalcoholic fatty liver disease (NAFLD), the methods for selecting carbonylated proteins were modified, and carbonylated proteins were profiled. The results showed that treadmill training reduced oxidative stress and the levels of intrahepatic triglyceride (IHTG). The changes in IHTG showed a significant positive correlation with oxidative stress as indicated by malondialdehyde level. Further results from proteomics illustrated that 17 functional proteins were susceptible to oxidative modification, and exercise protected three proteins from carbonylation. The latter three proteins may serve as both direct target proteins of oxidative stress and mediators contributing to the beneficial effects of exercise. In particular, a long-chain specific acyl-CoA dehydrogenase (ACADL) which was a key enzyme in lipid metabolism was not carbonylated and with higher activities in exercise group. These findings indicate that this modified technique is practical and powerful in selecting carbonylated proteins. Long-term treadmill training is effective in ameliorating oxidative stress and preventing the accumulation of IHTG. Among the 17 target proteins of oxidative modification, three proteins contribute to the beneficial effects of exercise. Preventing ACADL from carbonylation may be involved in the physiological mechanism of exercise-induced NAFLD improvement.
Assuntos
Fígado Gorduroso/metabolismo , Fígado/metabolismo , Carbonilação Proteica , Acil-CoA Desidrogenase/metabolismo , Animais , Biomarcadores/metabolismo , Terapia por Exercício , Fígado Gorduroso/prevenção & controle , Masculino , Malondialdeído/metabolismo , Hepatopatia Gordurosa não Alcoólica , Oxirredução , Estresse Oxidativo , Condicionamento Físico Animal , Mapas de Interação de Proteínas , Proteômica , Ratos , Ratos Sprague-Dawley , Triglicerídeos/metabolismoRESUMO
Up to now, there have been a few reports on the toxic components purified from black widow spider (Latrodectus tredecimguttatus) eggs. In the present study, a novel neurotoxic protein was purified from the eggs by gel filtration combined with ion-exchange chromatography. Its molecular weight was 23.752 kDa determined by electrospray mass spectrometry. The protein could block the neuromuscular transmission in mouse-isolated phrenic nerve-hemidiaphragm preparations completely in a reversible manner and activate tetrodotoxin-sensitive sodium current in rat dorsal root ganglion cells. The N-terminal sequence of the protein was identified by the Edman degradation to be N-S-I-A-D-D-R-Y-R-W-P-G-Y-P-G-A-G-L-I-P-Y-I-I-D-S-. When the sequence was used to search against protein database with a sequence query in Mascot engine there was no matched sequence or protein whereas the Basic Local Alignment Search Tool (BLAST) analysis indicated that no significant similarity was found. These results demonstrated that the protein (named Latroeggtoxin-I) is a novel neurotoxic protein purified from the eggs of black widow spiders.
Assuntos
Proteínas de Artrópodes , Viúva Negra/química , Bloqueadores Neuromusculares , Neurotoxinas , Óvulo/química , Transmissão Sináptica/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/química , Proteínas de Artrópodes/isolamento & purificação , Proteínas de Artrópodes/toxicidade , Gânglios Espinais/citologia , Gânglios Espinais/metabolismo , Masculino , Camundongos , Dados de Sequência Molecular , Bloqueadores Neuromusculares/efeitos adversos , Bloqueadores Neuromusculares/química , Bloqueadores Neuromusculares/isolamento & purificação , Bloqueadores Neuromusculares/farmacologia , Neurotoxinas/química , Neurotoxinas/isolamento & purificação , Neurotoxinas/toxicidade , Ratos , Ratos Sprague-DawleyRESUMO
Depression has a high incidence and seriously endangers human health. Accumulated evidence indicates that targeting neuroinflammation is a potential avenue for neuroprotection and thus depression prevention. Herein, the effects of latroeggtoxin-VI (LETX-VI), a bioactive protein from the eggs of spider Latrodectus tredecimguttatus, on lipopolysaccharide (LPS)-induced inflammation and depression were systematically investigated using RAW264.7 macrophages and depression mouse model. Pretreatment with LETX-VI suppressed LPS-evoked NF-κB signaling pathway activation, inhibited LPS-induced over-production of NO, iNOS, IL-6 and TNF-α; at the same time LETX-VI mitigated the inhibitory effect of LPS on the expression of anti-inflammatory factors such as Arg-1, thereby suppressing oxidative stress and excessive inflammation. Culture of PC12 cells with the conditioned medium of RAW264.7 cells pretreated with LETX-VI demonstrated the neuroprotective effect of LETX-VI due to its anti-inflammation effect. In the LPS-induced depression mouse model, pretreatment with LETX-VI improved the LPS-induced depression-like behaviors, inhibited the activation of microglia and astrocytes, prevented the down-regulation of Nurr1 expression and alleviated the LPS-caused adverse changes in the brain tissues. Taken together, these in vitro and in vivo findings provide powerful insights into the anti-inflammation-based neuroprotective and antidepressant mechanisms of LETX-VI, which is helpful to deeply reveal the biological effects and potential applications of LETX-VI.
Assuntos
Depressão , NF-kappa B , Ratos , Camundongos , Animais , Humanos , NF-kappa B/metabolismo , Depressão/metabolismo , Lipopolissacarídeos/farmacologia , Transdução de Sinais , Inflamação/metabolismo , Anti-Inflamatórios/uso terapêutico , Neurônios/metabolismoRESUMO
Previous work found that high-molecular-weight fractions in the egg extract of Latrodectus tredecimguttatus exhibited strong toxicities. For investigating the possible relationship of proteins in the eggs with the toxic effect, the protein composition of the eggs was analyzed using proteomic strategies and compared with that of the spider's venom. SDS-PAGE showed that the proteins of eggs were primarily distributed in the molecular weight range of higher than 55 kDa as well as around 34 kDa, having high abundance proteins with molecular weights of about 60 kDa and 130 kDa. A total of 157 proteins were identified from the egg extract, which were involved in important cellular functions and processes including catalysis, transport, and metabolism regulation. Comparison indicated that the protein composition of eggs is more complex than that of venom, and there are few similarities between the protein composition of the two materials, demonstrating that the eggs have their own distinct toxic mechanism.
Assuntos
Viúva Negra/metabolismo , Proteínas do Ovo/análise , Óvulo/química , Animais , Viúva Negra/patogenicidade , Peso Molecular , ProteômicaRESUMO
Although the central nervous system coordinates whole-body metabolism, the neural mechanism for hepatic steatosis remains unclear. This study is aimed to explore the neural mechanism of fasting-induced hepatic steatosis. Mice were pretreated with 6-hydroxydopamine to block sympathetic nerve activity before fasting, and to explore the potential effects of chemical sympathectomy on fasting-induced hepatic steatosis and transcriptional changes. Twenty-four hours fasting led to obvious hepatic steatosis, low-core temperature, and similar effects to cold-induced white adipose lipolysis. The alterations in hepatic mRNA expression revealed that the hepatic lipid accumulation did not result from an increase in hepatic lipogenesis or a decrease in fatty acid oxidation but from enhanced fatty acid uptake as indicated by upregulation of CD36. Blockage of the sympathetic nervous system via chemical sympathectomy attenuated fasting-induced hepatic steatosis and suppressed CD36 upregulation in the liver, but did not obviously alter the expression of genes associated with lipogenesis or fatty acid oxidation. These findings indicate that the sympathetic nervous system orchestrates the mechanism for fasting-induced hepatic steatosis via modulating CD36 expression and adipose fat trafficking into the liver, which provides clues to reveal new targets for fatty liver diseases.
Assuntos
Jejum , Fígado Gorduroso , Camundongos , Animais , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Lipogênese/fisiologia , Fígado , Ácidos Graxos/metabolismo , Ácidos Graxos/farmacologia , Camundongos Endogâmicos C57BLRESUMO
While intermittent fasting is a safe strategy to benefit health, it remains unclear whether a "timer" exists in vivo to record fasting duration and trigger a transcriptional switch. Here, we map a circadian transcriptional pathway atlas from 600 samples across four metabolic tissues of mice under five feeding regimens. Results show that 95.6% of detected canonical pathways are rhythmic in a tissue-specific and feeding-regimen-specific manner, while only less than 25% of them induce changes in transcriptional function. Fasting for 16 h initiates a circadian resonance of 43 pathways in the liver, and the resonance punctually switches following refeeding. The hepatic proteasome coordinates the resonance, and most genes encoding proteasome subunits display a 16-h fasting-dependent transcriptional switch. These findings indicate that the hepatic proteasome may serve as a fasting timer and a coordinator of pathway transcriptional resonance, which provide a target for revealing the underlying mechanism of intermittent fasting.
Assuntos
Relógios Circadianos , Jejum , Camundongos , Animais , Jejum/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ritmo Circadiano/genética , Regulação da Expressão Gênica , Fígado/metabolismoRESUMO
Toxoplasma gondii (T. gondii) is an important pathogen that can cause serious public health problems. Currently, therapeutic drugs for toxoplasmosis present serious side effects, researches on more effective and novel substances with relatively low toxicity are urgently needed. Spider venoms comprise diverse novel pharmacological compounds. However, the anti-T. gondii activity of spider venoms remains largely unknown. This study was carried out to evaluate the anti-parasitic effect of spider venoms from Ornitoctonus huwena (HWVM) and Chilobrachys jingzhao (JZVM) against T. gondii tachyzoites in vitro and in vivo. Cytotoxic activity of HWVM and JZVM to HeLa cells was determined by MTT cell viability assays. Low doses (3.125, 6.25 and 12.5⯵g/mL) of HWVM and JZVM displayed low toxicity to HeLa cells. Trypan blue exclusion assay indicated that either of HWVM and JZVM affected the viability of tachyzoites in a time-dependent manner. Both spider venoms inhibited the invasion and proliferation of tachyzoites in vitro (pâ¯<â¯0.05). Moreover, Mice treated with HWVM after infection with 2â¯×â¯103T. gondii tachyzoites showed a better survival rate than mice treated with saline alone (pâ¯<â¯0.05), while mice treated with JZVM did not. Our findings indicate that HWVM is a promising agent for the treatment of toxoplasmosis.
Assuntos
Venenos de Aranha/farmacologia , Venenos de Aranha/toxicidade , Toxoplasma/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Feminino , Células HeLa , Humanos , Camundongos , Aranhas/química , Toxoplasma/patogenicidadeRESUMO
Black widow spider is one of the most poisonous spiders in the world. Up to now, there have been few systematic analyses of the spider venom components, and the mechanism of action of the venom has not been completely understood. In this work, we employed combinative proteomic strategy to analyze the venom collected from living adult spider Latrodectus tredecimguttatus by electrical stimulation. The experiments demonstrated that the venom is primarily composed of high molecular weight proteins and has high abundance proteins around 100 kDa. The content of peptides and proteins with low molecular weight is low. A total of 75 nonredundant venom proteins with distinct function were unambiguously identified. Besides the known black widow spider venom proteins including latrotoxins, a variety of hydrolases and other proteins with special activity were found in the venom, such as proteinase, phospholipase, phosphatase, nuclease, fucolectin, venom allergen antigen 5-like protein and trypsin inhibitor, and so on. Their possible biological actions and relationship with latrodectism were discussed. The results help to understand the complexity and action mechanism of L. tredecimguttatus venom.
Assuntos
Viúva Negra/química , Proteínas/análise , Proteômica , Venenos de Aranha/análise , Sequência de Aminoácidos , Animais , Cromatografia Líquida , Eletroforese em Gel de Poliacrilamida , Feminino , Espectrometria de Massas , Dados de Sequência Molecular , Peptídeos/análise , Proteínas/química , Proteínas/classificação , Venenos de Aranha/químicaRESUMO
Lycosin-I, a spider peptide isolated from the venom of the spider Lycosa singoriensis, has anti-bacteria and anti-cancer properties in organisms. However, cardiovascular effects of Lycosin-I have not been studied. In this study, we investigated for the first time the vasodilator and hypotensive effects of Lycosin-I and the possible mechanisms, in order to develop a promising treatment for hypertension-related diseases. For in vitro experiments, thoracic aortas were isolated, and divided into two groups, endothelium-intact and endothelium-denuded aortic rings. Lycosin-I induced a remarkable dose-dependent relaxation in endothelium-intact aortic rings pre-treated with phenylephrine (pâ¯<â¯0.05), while it showed no obvious vasodilator effects in endothelium-denuded aortic rings (pâ¯>â¯0.05). The vasodilator effects of Lycosin-I were significantly weakened by a nitric oxide synthase (NOS) inhibitor, L-NAME (pâ¯<â¯0.001) and a selective inhibitor of nitric oxide (NO)-sensitive soluble guanylate cyclase (sGC), ODQ (pâ¯<â¯0.05), respectively. The levels of endothelial nitric oxide synthase (eNOS) phosphorylation and the NO production were significantly higher in human umbilical vascular endothelial cells pre-cultured with Lycosin-I than the control (pâ¯<â¯0.001), determined via western blot analysis and ozone-chemiluminescence technology. For in vivo experiments, arterial and venous catheters were inserted for mean arterial pressure (MAP) recording and drug administration in anaesthetized spontaneously hypertensive rats. Lycosin-I caused a transient drop of MAP 2â¯min after the administration compared with the control (pâ¯<â¯0.001). In conclusion, Lycosin-I has the potential to be an anti-hypertensive drug by endothelium-dependent vasodilatation, in which eNOS and NO-sensitive sGC are two main involved factors.
Assuntos
Anti-Hipertensivos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Aorta Torácica/metabolismo , Proteínas de Artrópodes/farmacologia , Hipotensão/induzido quimicamente , Venenos de Aranha/farmacologia , Aranhas/química , Vasodilatação/efeitos dos fármacos , Vasodilatadores/química , Vasodilatadores/farmacologia , Animais , Anti-Hipertensivos/química , Peptídeos Catiônicos Antimicrobianos/química , Aorta Torácica/patologia , Proteínas de Artrópodes/química , Hipotensão/metabolismo , Hipotensão/patologia , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Sprague-Dawley , Venenos de Aranha/químicaRESUMO
Heteropoda venatoria is a venomous spider species distributed worldwide and has a characteristic habit of feeding on insects. Reverse-phase high-performance liquid chromatography and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry analyses revealed that H. venatoria venom contains hundreds of peptides with a predominant molecular weights of 3000-5000 Da. Intra-abdominal injection of the venom had severe toxic effects on cockroaches and caused death at higher concentrations. The LD50 was 28.18 µg/g of body weight in the cockroach. It was found that the venom had potent inhibitory effect on voltage-gated sodium channels (VGSCs) in Periplaneta americana cockroach dorsal unpaired median (DUM) neurons with an IC50 values of 6.25 ± 0.02 µg/mL. However, 100 µg/mL venom only partially blocked VGSC currents in rat dorsal root ganglion cells, a much lower inhibitory effect than that on DUM VGSCs. Our results indicate that the venom of H. venatoria contains diverse neurotoxins that might become new leads for bioinsecticides.
Assuntos
Proteínas de Artrópodes/farmacologia , Proteínas de Insetos/antagonistas & inibidores , Venenos de Aranha/farmacologia , Aranhas , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Animais , Proteínas de Artrópodes/química , Cromatografia Líquida de Alta Pressão , Baratas/efeitos dos fármacos , Dose Letal Mediana , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Venenos de Aranha/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/químicaRESUMO
Synaptotagmin I (Syt I) is most abundant in the brain and is involved in multiple cellular processes. Its two C2 domains, C2A and C2B, are the main functional regions. Our present study employed a pull-down combined with proteomic strategy to identify the C2 domain-interacting proteins to comprehensively understand the biological roles of the C2 domains and thus the functional diversity of Syt I. A total of 135 non-redundant proteins interacting with the C2 domains of Syt I were identified. Out of them, 32 and 64 proteins only bound to C2A or C2B domains, respectively, and 39 proteins bound to both of them. Compared with C2A, C2B could bind to many more proteins particularly those involved in synaptic transmission and metabolic regulation. Functional analysis indicated that Syt I may exert impacts by interacting with other proteins on multiple cellular processes, including vesicular membrane trafficking, synaptic transmission, metabolic regulation, catalysis, transmembrane transport and structure formation, etc. These results demonstrate that the functional diversity of Syt I is higher than previously expected, that its two domains may mediate the same and different cellular processes cooperatively or independently, and that C2B domain may play even more important roles than C2A in the functioning of Syt I. This work not only further deepened our understanding of the functional diversity of Syt I and the functional differences between its two C2 domains, but also provided important clues for the further related researches.