RESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an emerging pathogenic coronavirus, has been reported to cause excessive inflammation and dysfunction in multiple cells and organs, but the underlying mechanisms remain largely unknown. Here we showed exogenous addition of SARS-CoV-2 envelop protein (E protein) potently induced cell death in cultured cell lines, including THP-1 monocytic leukemia cells, endothelial cells, and bronchial epithelial cells, in a time- and concentration-dependent manner. SARS-CoV-2 E protein caused pyroptosis-like cell death in THP-1 and led to GSDMD cleavage. In addition, SARS-CoV-2 E protein upregulated the expression of multiple pro-inflammatory cytokines that may be attributed to activation of NF-κB, JNK and p38 signal pathways. Notably, we identified a natural compound, Ruscogenin, effectively reversed E protein-induced THP-1 death via inhibition of NLRP3 activation and GSDMD cleavage. In conclusion, these findings suggested that Ruscogenin may have beneficial effects on preventing SARS-CoV-2 E protein-induced cell death and might be a promising treatment for the complications of COVID-19.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Células Endoteliais , Piroptose/fisiologiaRESUMO
BACKGROUND AND PURPOSE: Cerebral ischemiaâreperfusion injury causes significant harm to human health and is a major contributor to stroke-related deaths worldwide. Current treatments are limited, and new, more effective prevention and treatment strategies that target multiple cell components are urgently needed. Leucine-rich alpha-2 glycoprotein 1 (Lrg1) appears to be associated with the progression of cerebral ischemiaâreperfusion injury, but the exact mechanism of it is unknown. METHODS: Wild-type (WT) and Lrg1 knockout (Lrg1-/-) mice were used to investigate the role of Lrg1 after cerebral ischemiaâreperfusion injury. The effects of Lrg1 knockout on brain infarct volume, bloodâbrain barrier permeability, and neurological score (based on 2,3,5-triphenyl tetrazolium chloride, evans blue dye, hematoxylin, and eosin staining) were assessed. Single-cell RNA sequencing (scRNA-seq), immunofluorescence, and microvascular albumin leakage tests were utilized to investigate alterations in various cell components in brain tissue after Lrg1 knockout. RESULTS: Lrg1 expression was increased in various cell types of brain tissue after cerebral ischemiaâreperfusion injury. Lrg1 knockout reduced cerebral edema and infarct size and improved neurological function after cerebral ischemiaâreperfusion injury. Single-cell RNA sequencing analysis of WT and Lrg1-/- mouse brain tissues after cerebral ischemiaâreperfusion injury revealed that Lrg1 knockout enhances bloodâbrain barrier (BBB) by upregulating claudin 11, integrin ß5, protocadherin 9, and annexin A2. Lrg1 knockout also promoted an anti-inflammatory and tissue-repairing phenotype in microglia and macrophages while reducing neuron and oligodendrocyte cell death. CONCLUSIONS: Our results has shown that Lrg1 mediates numerous pathological processes involved in cerebral ischemiaâreperfusion injury by altering the functional states of various cell types, thereby rendering it a promising therapeutic target for cerebral ischemiaâreperfusion injury.
Assuntos
Isquemia Encefálica , Traumatismo por Reperfusão , Animais , Humanos , Camundongos , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Isquemia Encefálica/metabolismo , Traumatismo por Reperfusão/metabolismo , Análise de Sequência de RNARESUMO
ABSTRACT: Ubiquitin E3 ligases are a structurally conserved family of enzymes that exert a variety of regulatory functions in immunity, cell death, and tumorigenesis through the ubiquitination of target proteins. Emerging evidence has shown that E3 ubiquitin ligases play crucial roles in the pathogenesis of endothelial dysfunction and related vascular diseases. Here, we reviewed the new findings of E3 ubiquitin ligases in regulating endothelial dysfunction, including endothelial junctions and vascular integrity, endothelial activation, and endothelial apoptosis. The critical role and potential mechanism of E3 ubiquitin ligases in vascular diseases, such as atherosclerosis, diabetes, hypertension, pulmonary hypertension, and acute lung injury, were summarized. Finally, the clinical significance and potential therapeutic strategies associated with the regulation of E3 ubiquitin ligases were also proposed.
Assuntos
Ubiquitina-Proteína Ligases , Doenças Vasculares , Humanos , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação , Ubiquitina/metabolismo , Proteínas , Doenças Vasculares/tratamento farmacológicoRESUMO
Vitamin K, a necessary nutritional supplement for human, has been found to exhibit anti-inflammatory activity. In the present study, we investigated the effects of vitamin K family on lipopolysaccharide (LPS) plus nigericin induced pyroptosis and explored the underlying mechanism of its action in THP-1 monocytes. Results showed that vitamin K3 treatment significantly suppressed THP-1 pyroptosis, but not vitamin K1 or K2, as evidenced by increased cell viability, reduced cellular lactate dehydrogenase (LDH) release and improved cell morphology. Vitamin K3 inhibited NLRP3 expression, caspase-1 activation, GSDMD cleavage and interleukin (IL)-1ß secretion in pyrophoric THP-1 cells. In addition, vitamin K3 inhibited the pro-inflammatory signaling pathways including nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK). Vitamin K3 treatment also attenuated tissue damage and reduced serum LDH, IL-1ß and IL-6 levels in LPS-induced systemic inflammation of mice. The reduced myeloperoxidase (MPO) activityand F4/80 expression indicated that vitamin K3 effectively reduced the infiltration of neutrophils and macrophages. Moreover, NLRP3 expression in monocytes/macrophages were also decreased in vitamin K3-treatedmice after LPS challenge. These findings suggest that vitamin K3 potently alleviates systemic inflammation and organ injury via inhibition of pyroptosis in monocytes and may serve as a novel therapeutic strategy for patients with inflammatory diseases.
Assuntos
Sistema de Sinalização das MAP Quinases , NF-kappa B , Humanos , Camundongos , Animais , NF-kappa B/metabolismo , Vitamina K 3/farmacologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Piroptose , Células THP-1 , Lipopolissacarídeos/farmacologia , InflamaçãoRESUMO
Emerging evidence suggests that endothelial activation plays a central role in the pathogenesis of acute respiratory distress syndrome (ARDS) and multiorgan failure in patients with coronavirus disease 2019 (COVID-19). However, the molecular mechanisms underlying endothelial activation in COVID-19 patients remain unclear. In this study, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral proteins that potently activate human endothelial cells were screened to elucidate the molecular mechanisms involved in endothelial activation. It was found that nucleocapsid protein (NP) of SARS-CoV-2 significantly activated human endothelial cells through Toll-like receptor 2 (TLR2)/NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways. Moreover, by screening a natural microbial compound library containing 154 natural compounds, simvastatin was identified as a potent inhibitor of NP-induced endothelial activation. Remarkably, though the protein sequences of N proteins from coronaviruses are highly conserved, only NP from SARS-CoV-2 induced endothelial activation. The NPs from other coronaviruses such as SARS-CoV, Middle East respiratory syndrome coronavirus (MERS-CoV), HUB1-CoV, and influenza virus H1N1 did not activate endothelial cells. These findings are consistent with the results from clinical investigations showing broad endotheliitis and organ injury in severe COVID-19 patients. In conclusion, the study provides insights on SARS-CoV-2-induced vasculopathy and coagulopathy and suggests that simvastatin, an FDA-approved lipid-lowering drug, may help prevent the pathogenesis and improve the outcome of COVID-19 patients. IMPORTANCE Coronavirus disease 2019 (COVID-19), caused by the betacoronavirus SARS-CoV-2, is a worldwide challenge for health care systems. The leading cause of mortality in patients with COVID-19 is hypoxic respiratory failure from acute respiratory distress syndrome (ARDS). To date, pulmonary endothelial cells (ECs) have been largely overlooked as a therapeutic target in COVID-19, yet emerging evidence suggests that these cells contribute to the initiation and propagation of ARDS by altering vessel barrier integrity, promoting a procoagulative state, inducing vascular inflammation and mediating inflammatory cell infiltration. Therefore, a better mechanistic understanding of the vasculature is of utmost importance. In this study, we screened the SARS-CoV-2 viral proteins that potently activate human endothelial cells and found that nucleocapsid protein (NP) significantly activated human endothelial cells through TLR2/NF-κB and MAPK signaling pathways. Moreover, by screening a natural microbial compound library containing 154 natural compounds, simvastatin was identified as a potent inhibitor of NP-induced endothelial activation. Our results provide insights on SARS-CoV-2-induced vasculopathy and coagulopathy, and suggests that simvastatin, an FDA-approved lipid-lowering drug, may benefit to prevent the pathogenesis and improve the outcome of COVID-19 patients.
Assuntos
Proteínas do Nucleocapsídeo de Coronavírus/metabolismo , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Células Endoteliais/virologia , SARS-CoV-2 , Transdução de Sinais , Sinvastatina/farmacologia , COVID-19/virologia , Linhagem Celular , Células Endoteliais da Veia Umbilical Humana , Humanos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Receptor 2 Toll-Like/metabolismoRESUMO
BACKGROUND AND PURPOSE: Nonmuscle myosin heavy chain IIA, played an essential role in the promotion of tight junction injury in vascular endothelial cells under oxygen glucose deprivation condition. Rat microvascular endothelial cells had been confirmed to have the susceptibility to ox-LDL stimulation under OGD condition. We proposed the hypothesis that lipid metabolic reprogramming might be the root cause for damage to RBMCs tight junction. METHODS: Untargeted shotgun and targeted lipid metabolomics mass spectrometry approaches combined with principal component analysis was applied to better define the lipids contributing to the variance observed between control and different OGD time. The protein expression of tight junction of RBMCs: occludin, claudin-5, and ZO-1 were detected with immunofluorescence staining and western blot. The proof of the interaction between NMMHC IIA and SREBP1 was investigated via GST-pull down, while their specific binding fragments were also confirmed. The regulation mechanism of NMMHC IIA on SREBP1 was investigated to explore downstream regulatory signaling pathways. RESULTS: Untargeted and targeted shotgun lipidomics data revealed that OGD might be the conditional factor in reshaping lipid components. Mechanistic studies showed that with the increase of OGD time, PCA analysis of lipidomics obtained from RBMCs indicated their specificity in reshaping lipid components, while ≥80% major lipid components phospholipids and sphingolipids transferred from phospholipids, sphingolipids, and neutral lipids, of which neutral lipids taken the largest proportion with OGD time course. Perturbing reprogramming of lipid composition was less susceptible to OGD condition via knockdown of NMMHC IIA of vascular endothelial cells. Knockdown of NMMHC IIA could promote tight junction defense to OGD condition. NMMHC IIA could directly bind with SREBP1, then could affect sterol regulatory element binding protein-1 to adjust lipid metabolize reprogramming of RBMCs. CONCLUSIONS: Mechanistic studies showed that perturbing reprogramming of lipid composition could enhance tight junction damage, which was mediated by the opposing effects of NMMHC IIA.
Assuntos
Células Endoteliais , Junções Íntimas , Animais , Células Endoteliais/metabolismo , Glucose/metabolismo , Lipídeos , Ratos , Transdução de Sinais , Junções Íntimas/metabolismoRESUMO
Inflammation-induced activation and dysfunction of endothelial cells play an important role in the pathology of multiple vascular diseases. Nicaraven, a potent hydroxyl radical scavenger, has recently been found to have anti-inflammatory roles; however, the mechanism of its action is not fully understood. Here we investigated the effects of Nicaraven on tumor necrosis factor α (TNFα) - induced inflammatory response in human umbilical vein endothelial cells and we explore the underlying mechanisms related to the nuclear factor-κB (NF-κB) signaling pathway. Our results showed that Nicaraven significantly reduced the reactive oxygen species production after TNFα stimulation. Nicaraven suppressed TNFα-induced mRNA expression of multiple adhesion molecules and pro-inflammatory cytokines, including vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), E-selectin, MCP-1, TNFα, interleukin-1ß (IL-1ß), IL-6, and IL-8. In addition, Nicaraven inhibited monocyte adhesion and reduced the protein levels of VCAM-1 and ICAM-1. Mechanistically, Nicaraven prevented TNFα-induced activation of NF-κB signaling pathway by suppressing the phosphorylation of NF-κB p65, IκBα, and IκB kinase (IKK)α/ß, stabilizing IκBα, and inhibiting the translocation of p65 from cytosol to nucleus. Finally, we showed that Nicaraven improved the functions of endothelial cells, seen as the upregulation of endothelial nitric oxide synthase and increased nitric oxide levels. Our findings indicated that Nicaraven effectively inhibits TNFα-induced endothelial activation and inflammatory response at least partly through inhibiting NF-κB signaling pathway.
Assuntos
NF-kappa B , Células Endoteliais da Veia Umbilical Humana , Humanos , Transdução de SinaisRESUMO
Pyroptosis is a recently discovered inflammatory form of programmed cell death which is mostly triggered by infection with intracellular pathogens and critically contributes to inflammation. Mitigating pyroptosis may be a potential therapeutic target in inflammatory diseases. However, small chemicals to reduce pyroptosis is still elusive. In the present study, we screened 155 chemicals from a microbial natural product library and found Geldanamycin, an HSP90 inhibitor, profoundly rescued THP-1 cells from pyroptosis induced by LPS plus Nigericin treatment. Consistently, other HSP90 inhibitors, including Radicicol, 17-DMAG and 17-AAG, all ameliorated pyroptosis in THP-1 cells by suppressing the inflammasome/Caspase-1/GSDMD signal pathway in pyroptosis. HSP90 inhibition compromised the protein stability of NLRP3, a critical component of the inflammasome. Moreover, up-regulated HSP70 may also contribute to this effect. HSP90 inhibition may thus be a potential therapeutic strategy in the treatment of inflammatory diseases in which pyroptosis plays a role.
Assuntos
Benzoquinonas/farmacologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Inflamassomos/efeitos dos fármacos , Inflamação/metabolismo , Lactamas Macrocíclicas/farmacologia , Piroptose/efeitos dos fármacos , Caspase 1/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Proteínas de Choque Térmico HSP72/metabolismo , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Inflamassomos/metabolismo , Inflamação/tratamento farmacológico , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lipopolissacarídeos/toxicidade , Macrolídeos/farmacologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Nigericina/toxicidade , Proteínas de Ligação a Fosfato/metabolismo , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Estabilidade Proteica , Transdução de Sinais/efeitos dos fármacos , Células THP-1 , Regulação para CimaRESUMO
Brain-type glycogen phosphorylase (pygb) is one of the rate-limiting enzymes in glycogenolysis that plays a crucial role in the pathogenesis of type 2 diabetes mellitus. Here we investigated the role of pygb in high-glucose (HG)-induced cardiomyocyte apoptosis and explored the underlying mechanisms, by using the specific pygb inhibitors or pygb siRNA. Our results show that inhibition of pygb significantly attenuates cell apoptosis and oxidative stress induced by HG in H9c2 cardiomyocytes. Inhibition of pygb improved glucose metabolism in cardiacmyocytes, as evidenced by increased glycogen content, glucose consumption, and glucose transport. Mechanistically, pygb inhibition activates the Akt-GSK-3ß signaling pathway and suppresses the activation of NF-κB in H9c2 cells exposed to HG. Additionally, pygb inhibition promotes the expression and the translocation of hypoxia-inducible factor-1α (HIF-1α) after HG stimulation. However, the changes in glucose metabolism and HIF-1α activation mediated by pygb inhibition are significantly reversed in the presence of the Akt inhibitor MK2206. In conclusion, this study found that inhibition of pygb prevents HG-induced cardiomyocyte apoptosis via activation of Akt-HIF-α.
Assuntos
Apoptose , Encéfalo/enzimologia , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/complicações , Glucose/toxicidade , Glicogênio Fosforilase/antagonistas & inibidores , Miócitos Cardíacos/metabolismo , Animais , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/patologia , Linhagem Celular , Glicogênio Sintase Quinase 3 beta/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Transdução de Sinais , Edulcorantes/toxicidadeRESUMO
BACKGROUND Protein kinase R (PKR) is implicated in the inflammatory response to bacterial infection while the role of PKR in sepsis-induced acute kidney injury (AKI) is largely unknown. This study aimed to investigate the effects of the specific PKR inhibitor C16 (C13H8N4OS) on lipopolysaccharide (LPS)-induced AKI, and its mechanisms of action. MATERIAL AND METHODS C57BL/6J mice were injected intraperitoneally with C16 or vehicle 1 h before the LPS challenge and then injected intraperitoneally with LPS or 0.9% saline. After the LPS challenge, histopathological damage, renal function, and levels of proinflammatory cytokines were assessed. All the related signaling pathways were analyzed. RESULTS C16 effectively inhibited LPS-induced renal elevation of proinflammatory cytokines and chemokines. C16 prevented NF-kappaB activation and suppressed the PKR/eIF2alpha signaling pathway in AKI after the LPS challenge. Furthermore, C16 significantly inhibited pyroptosis during AKI, as evidenced by decreased renal levels of apoptosis-associated speck-like protein; NACHT, LRR, NLR Family Pyrin Domain-Containing 3; caspase-1; interleukin (IL)-1ß; and IL-18. CONCLUSIONS Our findings suggest that inhibition by C16 ameliorated LPS-induced renal inflammation and injury, at least partly through modulation of the pyroptosis signal pathway in the kidney.
Assuntos
Injúria Renal Aguda , Indóis/farmacologia , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Piroptose/efeitos dos fármacos , Sepse , Transdução de Sinais/efeitos dos fármacos , Tiazóis/farmacologia , eIF-2 Quinase/antagonistas & inibidores , Injúria Renal Aguda/tratamento farmacológico , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Animais , Camundongos , Sepse/complicações , Sepse/tratamento farmacológico , Sepse/metabolismo , Sepse/patologia , eIF-2 Quinase/metabolismoRESUMO
Detection and degradation of foreign nucleic acids is an ancient form of host defense. However, the underlying mechanisms are not completely clear. MCPIP1 is an endoribonuclease and an important regulator in both innate and adaptive immunity by targeting inflammatory mRNA degradation. Here we report that MCPIP1 RNase can also selectively detect and degrade the mRNAs encoded by transfected plasmids. In transient transfection, MCPIP1 expression potently degraded the mRNA from exogenously transfected vectors, which is independent on the vector, genes and cell types used. Conversely, the expression of transfected plasmids in MCPIP1-null cells is significantly higher than that in wild-type cells. Interestingly, overexpression of MCPIP1 or MCPIP1 deficiency does not affect the expression of the exogenous genes incorporated into the host genome in a stable cell line or the global gene expression of host genome. This ability is not associated with PKR/RNase L system, as PKR inhibitors does not block MCPIP1-mediated mRNA degradation of exogenously transfected genes. Lastly, expression of MCPIP1 suppressed replication of Zika virus in infected cells. The study may provide a model for understanding the antiviral mechanisms of MCPIP1, and a putative tool to increase the expression of transfected exogenous genes.
Assuntos
Estabilidade de RNA , RNA Mensageiro/química , RNA Viral/química , Ribonucleases/fisiologia , Fatores de Transcrição/fisiologia , Replicação Viral/fisiologia , Infecção por Zika virus/genética , Zika virus/genética , Vetores Genéticos , Células HEK293 , Células HeLa , Humanos , TransfecçãoRESUMO
It has been recently reported that CD38 was highly expressed in adipose tissues from obese people and CD38-deficient mice were resistant to high-fat diet (HFD)-induced obesity. However, the role of CD38 in the regulation of adipogenesis and lipogenesis is unknown. In this study, to explore the roles of CD38 in adipogenesis and lipogenesis in vivo and in vitro, obesity models were generated with male CD38-/- and WT mice fed with HFD. The adipocyte differentiations were induced with MEFs from WT and CD38-/- mice, 3T3-L1 and C3H10T1/2 cells in vitro. The lipid accumulations and the alternations of CD38 and the genes involved in adipogenesis and lipogenesis were determined with the adipose tissues from the HFD-fed mice or the MEFs, 3T3-L1 and C3H10T1/2 cells during induction of adipocyte differentiation. The results showed that CD38-/- male mice were significantly resistant to HFD-induced obesity. CD38 expressions in adipocytes were significantly increased in WT mice fed with HFD, and the similar results were obtained from WT MEFs, 3T3-L1 and C3H10T1/2 during induction of adipocyte differentiation. The expressions of PPARγ, AP2 and C/EBPα were markedly attenuated in adipocytes from HFD-fed CD38-/- mice and CD38-/- MEFs at late stage of adipocyte differentiation. Moreover, the expressions of SREBP1 and FASN were also significantly decreased in CD38-/- MEFs. Finally, the CD38 deficiency-mediated activations of Sirt1 signalling were up-regulated or down-regulated by resveratrol and nicotinamide, respectively. These results suggest that CD38 deficiency impairs adipogenesis and lipogenesis through activating Sirt1/PPARγ-FASN signalling pathway during the development of obesity.
Assuntos
ADP-Ribosil Ciclase 1/deficiência , Adipogenia , Tecido Adiposo/metabolismo , Lipogênese , PPAR gama/metabolismo , Transdução de Sinais , Sirtuína 1/metabolismo , ADP-Ribosil Ciclase 1/metabolismo , Adipócitos/metabolismo , Animais , Diferenciação Celular , Embrião de Mamíferos/citologia , Fibroblastos/metabolismo , Camundongos , NAD/metabolismoRESUMO
CD38 was first identified as a lymphocyte-specific antigen and then has been found to be widely expressed in a variety of cell types. The functions of CD38 are involved in numerous biological processes including immune responses. Here, we showed the downregulations of both TLR2 mRNA and protein in macrophages from CD38-/- mice and in CD38 knockdown RAW264.7 cells. Several NF-κB-binding motifs in the promoter region of the TLR2 gene were identified by the bioinformatics analysis and were confirmed by the luciferase activity assay with the different truncated TLR2 promoters. CD38 deficiency resulted in the reduction of NF-κB p65 and acetyl-NF-κB p65 (Ac-p65) levels as determined by Western blot. The expression of Sirt1 did not change, but an increased activity of Sirt1 was observed in CD38-deficient macrophages. Inhibition of the Sirt1/NF-κB signaling pathway resulted in downregulation of TLR2 expression in RAW264.7 cells. However, re-expression of CD38 in the knockdown clones reversed the effect on Sirt1/NF-κB/TLR2 signaling, which is NAD-dependent. Moreover, the inflammatory cytokines including G-CSF, IL-1alpha, IL-6, MCP-1, MIP-1alpha, and RANTES were increased in CD38 knockdown RAW264.7 cells. Taken together, our data demonstrated that CD38 deficiency enhances inflammatory response in macrophages, and the mechanism may be partly associated with increased Sirt1 activity, which promoted NF-κB deacetylation and then inhibited expression of the TLR2 gene. Obviously, our study may provide an insight into the molecular mechanisms in CD38-mediated inflammation.
Assuntos
ADP-Ribosil Ciclase 1/deficiência , Inflamação/metabolismo , Macrófagos Peritoneais/metabolismo , Macrófagos/metabolismo , NF-kappa B/metabolismo , Sirtuína 1/metabolismo , ADP-Ribosil Ciclase 1/genética , ADP-Ribosil Ciclase 1/metabolismo , Animais , Western Blotting , Biologia Computacional , Inflamação/genética , Camundongos , Células RAW 264.7 , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Sirtuína 1/genética , Receptor 2 Toll-Like/metabolismoRESUMO
BACKGROUND: Nonalcoholic fatty liver disease is one of the most common liver diseases in the world and is a typical hepatic manifestation of metabolic syndrome which is characterized with lipid accumulation in liver. Nicotinamide phosphoribosyltransferase (NAMPT) has been recently identified as an enzyme involved in nicotinamide adenine dinucleotide (NAD+) biosynthesis and plays an important role in cellular metabolism in variety of organs in mammals. The aim of this study was to investigate the effects of NAMPT on high fat diet-induced hepatic steatosis. METHODS: Hepatic steatosis model was induced by high fat diet (HFD) in C57BL/6 mice in vivo. HepG2 and Hep1-6 hepatocytes were transfected with NAMPT vector plasmid or treated with NAMPT inhibitor FK866 and then incubated with oleic acid. Lipids accumulation was examined by HE staining or oil red staining. Quantitative RT-PCR and Western blot were used to measure expressions of the genes involved in lipogenic synthesis. RESULTS: FK866 significantly promoted liver steatosis in the mice fed with HFD and hepatic lipid accumulation in vitro, accompanied by the increases of the expressions of lipogenic genes such as sterol regulatory element-binding protein 1 (SREBP1) and fatty acid synthase (FASN). Nicotinamide mononucleotide (NMN) and NAD+ significantly rescued the actions of FK866 in vitro. In contrast, overexpression of NAMPT in HepG2 and Hep1-6 hepatocytes ameliorated hepatic lipid accumulation. In addition, FK866 decreased the protein levels of Sirt1 and phospho-AMPKα in liver of the HFD fed mice. Furthermore, Resveratrol, a Sirt1 activator, significantly reduced lipogenic gene expressions, while EX-527, a Sirt1 specific inhibitor, had the opposite effects. CONCLUSION: Our results demonstrated that inhibition of NAMPT aggravated the HFD- or oleic acid-induced hepatic steatosis through suppressing Sirt1-mediated signaling pathway. On the one hand, the inhibition of NAMPT reduced the production of NAD+ through inhibiting the NAD+ salvage pathway, resulting in the decrease of Sirt1 activity, and then attenuated the deacetylation of SREBP1 in which the inhibition of SREBP1 activity promoted the expressions of FASN and ACC. On the other hand, the reduced Sirt1 activity alleviated the activation of AMPKα to further enhance SREBP1 activities.
Assuntos
Proteínas Quinases Ativadas por AMP/genética , Citocinas/genética , Fígado/enzimologia , Nicotinamida Fosforribosiltransferase/genética , Hepatopatia Gordurosa não Alcoólica/genética , Sirtuína 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Acrilamidas/farmacologia , Animais , Carbazóis/farmacologia , Linhagem Celular , Citocinas/antagonistas & inibidores , Citocinas/metabolismo , Dieta Hiperlipídica/efeitos adversos , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica , Células Hep G2 , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Hepatócitos/patologia , Humanos , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NAD/farmacologia , Mononucleotídeo de Nicotinamida/farmacologia , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Nicotinamida Fosforribosiltransferase/metabolismo , Hepatopatia Gordurosa não Alcoólica/enzimologia , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/patologia , Ácido Oleico/farmacologia , Piperidinas/farmacologia , Resveratrol , Transdução de Sinais , Sirtuína 1/antagonistas & inibidores , Sirtuína 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Estilbenos/farmacologiaRESUMO
Microglia activation initiates a neurological deficit cascade that contributes to substantial neuronal damage and impairment following ischemia stroke. Toll-like receptor 4 (TLR4) has been demonstrated to play a critical role in this cascade. In the current study, we tested the hypothesis that hydroxysafflor yellow A (HSYA), an active ingredient extracted from Flos Carthami tinctorii, alleviated inflammatory damage, and mediated neurotrophic effects in neurons by inducing the TLR4 pathway in microglia. A non-contact Transwell co-culture system comprised microglia and neurons was treated with HSYA followed by a 1 mg/mL lipopolysaccharide (LPS) stimulation. The microglia were activated prior to neuronal apoptosis, which were induced by increasing TLR4 expression in the activated microglia. However, HSYA suppressed TLR4 expression in the activated microglia, resulting in less neuronal damage at the early stage of LPS stimulation. Western blot analysis and immunofluorescence indicated that dose-dependently HSYA down-regulated TLR4-induced downstream effectors myeloid differentiation factor 88 (MyD88), nuclear factor kappa b (NF-κB), and the mitogen-activated protein kinases (MAPK)-regulated proteins c-Jun NH2-terminal protein kinase (JNK), protein kinase (ERK) 1/2 (ERK1/2), p38 MAPK (p38), as well as the LPS-induced inflammatory cytokine release. However, HSYA up-regulated brain-derived neurotrophic factor (BDNF) expression. Our data suggest that HSYA could exert neurotrophic and anti-inflammatory functions in response to LPS stimulation by inhibiting TLR4 pathway-mediated signaling.
Assuntos
Chalcona/análogos & derivados , Microglia/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Quinonas/farmacologia , Receptor 4 Toll-Like/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Caspase 3/metabolismo , Chalcona/farmacologia , Técnicas de Cocultura , Citocinas/metabolismo , Regulação para Baixo , Feminino , Lipopolissacarídeos/farmacologia , Camundongos , Microglia/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Neurônios/enzimologia , Neurônios/metabolismo , Gravidez , Transporte Proteico , Transdução de Sinais , Receptor 4 Toll-Like/antagonistas & inibidores , Fator de Transcrição RelA/metabolismoRESUMO
Glutamate-mediated excitotoxicity is a major cause of ischemic brain damage. MK-801 confers neuroprotection by attenuating the activation of the N-methyl-d-aspartate (NMDA) receptor, but it failed in clinical use due to the short therapeutic window. Here we aim to investigate the effects of maslinic acid, a natural product from Olea europaea, on the therapeutic time window and dose range for the neuroprotection of MK-801. Rats were administered with maslinic acid intracerebroventricularly and cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) followed by reperfusion. MK-801 was administered at 1 h, 2 h, 3 h and 4 h after ischemia, respectively. The cerebral infarct volume was determined by 2,3,5-Triphenyltetrazolium chloride (TTC) staining, neuronal damage was assessed by Haematoxylin Eosin (H&E) staining, and the expression of glial glutamate transporters and glial fibrillary acidic protein (GFAP) was evaluated by immunohistochemistry and Western blot post-ischemia. Results showed that the presence of maslinic acid extended the therapeutic time window for MK-801 from 1 h to 3 h. Co-treatment of maslinic acid and MK-801 at a subthreshold dosage obviously induced neuroprotection after ischemia. The combination of these two compounds improved the outcome in ischemic rats. Moreover, maslinic acid treatment promoted the expression of GLT-1 and GFAP post-ischemia. These data suggest that the synergistic effect of maslinic acid on neurological protection might be associated with the improvement of glial function, especially with the increased expression of GLT-1. The combination therapy of maslinic acid and MK-801 may prove to be a potential strategy for treating acute ischemic stroke.
Assuntos
Isquemia Encefálica/tratamento farmacológico , Maleato de Dizocilpina/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Olea/química , Triterpenos/administração & dosagem , Animais , Isquemia Encefálica/etiologia , Isquemia Encefálica/metabolismo , Modelos Animais de Doenças , Maleato de Dizocilpina/farmacologia , Sinergismo Farmacológico , Quimioterapia Combinada , Regulação da Expressão Gênica/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/metabolismo , Proteínas de Transporte de Glutamato da Membrana Plasmática/metabolismo , Fármacos Neuroprotetores/farmacologia , Ratos , Triterpenos/farmacologiaRESUMO
Myocardial ischemic/reperfusion injury results from severe impairment of coronary blood supply and leads to irreversible cell death, with limited therapeutic possibilities. Asiatic acid is a pentacyclic triterpenoid derived from the tropical medicinal plant Centella asiatica and serves a variety of bioactivities. In this study, we determined the effect of asiatic acid on myocardial ischemia/reperfusion injury and investigated the underlying mechanisms, using an in vitro rat H9c2 cardiomyocytes model of oxygen-glucose deprivation/reoxygenation (OGD/R) injury. Results showed that pre-treatment with asiatic acid significantly augmented cell viability and prevented lactate dehydrogenase (LDH) release in a concentration-dependent manner after OGD/R exposure. Asiatic acid at 10 µM effectively inhibited apoptotic cell death, suppressed the activities of caspase-3 and caspase-9, and reversed Bax/Bcl-2 ratio in hypoxic H9c2 cells. In addition, asiatic acid improved mitochondrial function, as evidenced by reduced reactive oxygen species (ROS) accumulation, enhanced mitochondrial membrane potential and decreased intracellular calcium concentration. Using Western blot assay, we found that asiatic acid promoted the phosphorylation of Akt and subsequent inactivation of glycogen synthase kinase-3ß (GSK-3ß), and induced the expression of hypoxia-inducible factor 1α (HIF-1α) after OGD/R. The cardioprotective effects of asiatic acid were attenuated by the Akt or HIF-1α inhibitor. Taken together, these data suggested that asiatic acid exerted protective effects against OGD/R-induced apoptosis in cardiomyocytes, at least partly via the Akt/GSK-3ß/HIF-1α pathway.
RESUMO
CONTEXT: Genistein, one of the isoflavones derived from soybean seeds, has been reported to exert multiple bioactivities. However, the mechanism of its action on the central nervous system is not fully understood. OBJECTIVE: To investigate the cytoprotection of genistein and its molecular mechanism against H2O2-induced cell death in primary rat cortical neurons. MATERIALS AND METHODS: Genistein (0.01, 0.1, and 1 µM) were added into the primary rat neurons 24 h before and co-cultured with 500 µM H2O2 for 1 h. Neuronal injury was assessed by MTT, lactate dehydrogenase (LDH) assay, and Hoechst33258 staining. Intracellular reactive oxygen species (ROS) generation induced by H2O2 was determined. Neuronal apoptosis was evaluated by Bcl-2/Bax ratio as well as by caspase-9 and caspase-3 activities. The protein levels and phosphorylation of NF-κB/p65, IκB, JNK, and ERK were detected by western blots. RESULTS: Genistein pretreatment attenuated H2O2-mediated neuronal viability loss, nuclear condensation, and ROS generation in a concentration-dependent manner. Genistein exerted anti-apoptotic effects by reversing the apoptotic factors Bcl-2 and Bax ratio, along with the suppression of caspase-9 and caspase-3 activities. In addition, genistein down-regulated the expression of NF-κB/p65, and suppressed the phosphorylation of p65 and IκB. Genistein also inhibited H2O2-induced activation of the MAPK-signaling pathway including JNK and ERK. DISCUSSION AND CONCLUSION: The results indicated that genistein effectively protects cortical neurons against oxidative stress at least partly via inactivation of NF-κB as well as MAPK-signaling pathways, and suggested the possibility of this antioxidant for the prevention and treatment of stroke.
Assuntos
Córtex Cerebral/efeitos dos fármacos , Genisteína/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Estresse Oxidativo/efeitos dos fármacos , Animais , Antioxidantes/farmacologia , Córtex Cerebral/metabolismo , Relação Dose-Resposta a Droga , Sistema de Sinalização das MAP Quinases/fisiologia , NF-kappa B/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/fisiologia , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismoRESUMO
Endothelial cells are the crucial inner lining of blood vessels, which are pivotal in vascular homeostasis and integrity. However, these cells are perpetually subjected to a myriad of mechanical, chemical, and biological stresses that can compromise their plasma membranes. A sophisticated repair system involving key molecules, such as calcium, annexins, dysferlin, and MG53, is essential for maintaining endothelial viability. These components orchestrate complex mechanisms, including exocytosis and endocytosis, to repair membrane disruptions. Dysfunctions in this repair machinery, often exacerbated by aging, are linked to endothelial cell death, subsequently contributing to the onset of atherosclerosis and the progression of cardiovascular diseases (CVD) and stroke, major causes of mortality in the United States. Thus, identifying the core machinery for endothelial cell membrane repair is critically important for understanding the pathogenesis of CVD and stroke and developing novel therapeutic strategies for combating CVD and stroke. This review summarizes the recent advances in understanding the mechanisms of endothelial cell membrane repair. The future directions of this research area are also highlighted.
Assuntos
Doenças Cardiovasculares , Acidente Vascular Cerebral , Humanos , Células Endoteliais , Membrana Celular/metabolismo , Membranas , Doenças Cardiovasculares/metabolismo , Acidente Vascular Cerebral/metabolismoRESUMO
The structure proteins of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), such as nucleocapsid protein (N protein) and envelop protein (E protein), are considered to be the critical pro-inflammatory factors in coronavirus disease 2019 (COVID-19). Vitamin K3 has been reported to exert an anti-inflammatory effect. In this study, we investigated the protective effects of vitamin K3 on SARS-CoV-2 N protein induced-endothelial activation and SARS-CoV-2 E protein induced-cell death in THP-1 cells. The results showed that vitamin K3 reduced N protein-induced monocyte adhesion, suppressed the expression of adhesion molecules, and decreased the mRNA levels of pro-inflammatory cytokines in HLMECs. We confirmed that the effects of vitamin K3 on endothelial activation may be related to the inhibition of the NF-κB signal pathway. In addition, vitamin K3 reversed E protein-induced pyroptosis, inhibited NLRP3/GSDMD signal pathway and reduced the mRNA expression of pro-inflammatory cytokines in THP-1 cells. Our results also showed the protective effects of vitamin K3 on the SARS-CoV-2 structural protein-induced THP-1 cells pyroptosis and endothelial activation via NF-κB signaling pathway. These findings suggested that vitamin K3 potently suppressed the inflammatory response to prevent endothelial activation and monocyte pyroptosis induced by SARS-CoV-2 proteins. This may provide a new strategy for the treatment of COVID-19.