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BACKGROUND: Endothelial-mesenchymal transition (EndMT) induced by low shear stress plays an important role in the development of atherosclerosis. However, little is known about the correlation between hydrogen sulfide (H2S), a protective gaseous mediator in atherosclerosis and the process of EndMT. METHODS: We constructed a stable low-shear-stress-induced(2 dyn/cm2) EndMT model, acombined with the pretreatment method of hydrogen sulfide slow release agent(GYY4137). The level of MEST was detected in the common carotid artery of ApoE-/- mice with local carotid artery ligation. The effect of MEST on atherosclerosis development in vivo was verified using ApoE-/- mice were given tail-vein injection of endothelial-specific overexpressed and knock-down MEST adeno-associated virus (AAV). RESULTS: These findings confirmed that MEST is up-regulated in low-shear-stress-induced EndMT and atherosclerosis. In vivo experiments showed that MEST gene overexpression significantly promoted EndMT and aggravated the development of atherosclerotic plaques and MEST gene knockdown significantly inhibited EndMT and delayed the process of atherosclerosis. In vitro, H2S inhibits the expression of MEST and EndMT induced by low shear stress and inhibits EndMT induced by MEST overexpression. Knockdown of NFIL3 inhibit the up regulation of MEST and EndMT induced by low shear stress in HUVECs. CHIP-qPCR assay and Luciferase Reporter assay confirmed that NFIL3 binds to MEST DNA, increases its transcription and H2S inhibits the binding of NFIL3 and MEST DNA, weakening NFIL3's transcriptional promotion of MEST. Mechanistically, H2S increased the sulfhydrylation level of NFIL3, an important upstream transcription factors of MEST. In part, transcription factor NFIL3 restrain its binding to MEST DNA by sulfhydration. CONCLUSIONS: H2S negatively regulate the expression of MEST by sulfhydrylation of NFIL3, thereby inhibiting low-shear-stress-induced EndMT and atherosclerosis.
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Aterosclerose , Sulfeto de Hidrogênio , Camundongos , Animais , Humanos , Sulfeto de Hidrogênio/farmacologia , Sulfeto de Hidrogênio/metabolismo , Transição Endotélio-Mesênquima , Aterosclerose/genética , Aterosclerose/metabolismo , Endotélio/metabolismo , DNA/metabolismo , Apolipoproteínas E/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Transição Epitelial-MesenquimalRESUMO
Heart failure (HF) is a complex clinical syndrome caused by various cardiovascular diseases. Its main pathogenesis includes cardiomyocyte loss, myocardial energy metabolism disorder, and activation of cardiac inflammation. Due to the clinically unsatisfactory treatment of heart failure, different mechanisms need to be explored to provide new targets for the treatment of this disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a gene mainly related to familial hypercholesterolemia, was discovered in 2003. Aside from regulating lipid metabolism, PCSK9 may be involved in other biological processes such as apoptosis, autophagy, pyroptosis, inflammation, and tumor immunity and related to diabetes and neurodegenerative diseases. Recently, clinical data have shown that the circulating PCSK9 level is significantly increased in patients with heart failure, and it is related to the prognosis for heart failure. Furthermore, in animal models and patients with myocardial infarction, PCSK9 in the infarct margin area was also found to be significantly increased, which further suggested that PCSK9 might be closely related to heart failure. However, the specific mechanism of how PCSK9 participates in heart failure remains to be further explored. The purpose of this review is to summarize the potential mechanism of PCSK9's involvement in heart failure, thereby providing a new treatment strategy for heart failure.
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Insuficiência Cardíaca , Infarto do Miocárdio , Animais , Humanos , Pró-Proteína Convertase 9/genética , Pró-Proteína Convertase 9/metabolismo , Insuficiência Cardíaca/genética , InflamaçãoRESUMO
Atherosclerosis is a chronic inflammatory response that increases the risk of cardiovascular diseases. An in-depth study of the pathogenesis of atherosclerosis is critical for the treatment of atherosclerotic cardiovascular disease. The development of atherosclerosis involves many cells, such as endothelial cells, vascular smooth muscle cells, macrophages, and others. The considerable effects of macrophages in atherosclerosis are inextricably linked to macrophage polarization and the resulting phenotype. Moreover, the significant impact of macrophages on atherosclerosis depend not only on the function of the different macrophage phenotypes but also on the relative ratio of different phenotypes in the plaque. Research on atherosclerosis therapy indicates that the reduced plaque size and enhanced stability are partly due to modulating macrophage polarization. Therefore, regulating macrophage polarization and changing the proportion of macrophage phenotypes in plaques is a new therapeutic approach for atherosclerosis. This review provides a new perspective for atherosclerosis therapy by summarizing the relationship between macrophage polarization and atherosclerosis, as well as treatment targeting macrophage polarization.
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Aterosclerose/metabolismo , Macrófagos/metabolismo , Animais , Humanos , Ativação de MacrófagosRESUMO
Hydrogen sulfide (H2S) is an endogenous gaseous signaling molecule that plays important roles in the cardiovascular system. In our previous studies, we demonstrated that H2S regulates lipid metabolism. In the present study, we aimed to explore the mechanisms through which H2S regulates lipid metabolism in HepG2 cells in vitro. Treatment of the HepG2 cells with H2S inhibited the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9) and increased the level of lowdensity lipoprotein receptor (LDLR) in a time and dosedependent manner. The knockdown of PCSK9 by siRNA effectively increased the levels of LDLR and 1,1'dioctadecyl3,3,3',3'tetramethylindocarbocyanine perchloratelabeled LDL (DiILDL) uptake in the H2Streated HepG2 cells. Furthermore, the phosphoinositide 3kinase (PI3K)/protein kinase B (Akt)sterol regulatory element binding proteins 2 (SREBP2) signaling pathway was confirmed to be involved in H2Sregulated PCSK9 expression. Notably, the HepG2 cells were incubated with 30% serum and DiILDL for 24 h, and the results revealed that H2S increased lipid uptake, but caused no increase in lipid accumulation. On the whole, the findings of this study demonstrate that H2S is involved in the regulation of lipid metabolism in HepG2 cells through the regulation of the expression of PCSK9 via the PI3K/AktSREBP2 signaling pathway. To the very best of our knowledge, this study is the first to report that H2S can regulate the expression of PCSK9.
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Sulfeto de Hidrogênio/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Inibidores de PCSK9 , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Células Hep G2 , Humanos , Modelos Biológicos , Pró-Proteína Convertase 9/metabolismo , Receptores de LDL/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
Endothelial cells are the main components of the heart, blood vessels, and lymphatic vessels, which play an important role in regulating the physiological functions of the cardiovascular system. Endothelial dysfunction is involved in a variety of acute and chronic cardiovascular diseases. As a special type of epithelial-mesenchymal transition (EMT), endothelium to mesenchymal transition (EndMT) regulates the transformation of endothelial cells into mesenchymal cells accompanied by changes in the expression of various transcription factors and cytokines, which is closely related to vascular endothelial injury, vascular remodeling, myocardial fibrosis and valvar disease. Endothelial cells undergoing EndMT lose their endothelial characteristics and undergo a transition toward a more mesenchymal-like phenotype. However, the molecular mechanism of EndMT remains unclear. EndMT, as a type of endothelial dysfunction, can cause vascular remodeling which is a major determinant of atherosclerotic luminal area. Therefore, exploring the important signaling pathways in the process of EndMT may provide novel therapeutic strategies for treating atherosclerotic diseases.
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Aterosclerose/patologia , Transição Epitelial-Mesenquimal , Remodelação Vascular , Aterosclerose/complicações , Aterosclerose/metabolismo , Aterosclerose/fisiopatologia , Humanos , Neovascularização Patológica/complicações , Fator de Crescimento Transformador beta/metabolismoRESUMO
Ten-eleven translocation-2 (TET2) protein is a DNA demethylase that regulates gene expression through DNA demethylation and also plays important roles in various diseases including atherosclerosis. Endothelial dysfunction represents an early key event in atherosclerotic disease. The cystathionine-γ-lyase (CSE)/hydrogen sulfide (H2S) is a key endogenous system with protective effects on endothelial functions. In this study, we examined how TET2 regulates oxidized low-density lipoprotein (oxLDL)-induced dysfunction of human umbilical vein endothelial cells (HUVECs) and determined the role of the CSE/H2S system. Treatment with oxLDL resulted in downregulation of both TET2 expression and CSE/H2S system in HUVECs. TET2 was found to have protective effects on oxLDL-induced HUVEC dysfunction, which was confirmed with TET2 overexpression plasmid or TET2 shRNA plasmid. Moreover, TET2 was found to upregulate the CSE/H2S system and inhibit NF-κB activation, leading to decreased expression of ICAM-1 and VCAM-1 and attenuated adhesion of THP-1 cells to oxLDL-activated HUVECs. The protective effect of TET2 was reduced by treatment with CSE siRNA. Further studies revealed that CSE promoter region contains a well-defined CpG island. We also showed that TET2 enhanced 5-hydroxymethylcytosine (5hmC) level and promoted DNA demethylation of CSE gene promoter, leading to an increase in CSE expression. In conclusion, TET2 has protective effects on oxLDL-induced HUVEC dysfunction, likely through upregulating the CSE/H2S system by DNA demethylation of CSE gene promoter. TET2 may become a novel therapeutic target for endothelial dysfunction-associated vascular diseases.
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BACKGROUND AND AIMS: Proprotein convertase subtilisin/kexin 9 (PCSK9) has emerged as a popular target in the development of new cholesterol-lowering drugs and therapeutic interventions for atherosclerosis. PCSK9 could accelerate atherosclerosis through mechanisms beyond the degradation of the hepatic low-density lipoprotein receptor. Several clinical studies suggested that PCSK9 is involved in atherosclerotic inflammation. Accordingly, this study aimed to explore the role of PCSK9 in vascular inflammation that promotes atherosclerotic progression. METHODS: We examined whether PCSK9 silencing via transduction with the lentivirus-mediated PCSK9 shRNA (LV-PCSK9 shRNA) vector affects the formation of vascular lesions in hyperlipidemia-induced atherosclerosis in apolipoprotein E knockout (apoE KO) mice. In vitro, the effects of PCSK9 on oxLDL-induced macrophages inflammation were investigate using LV-PCSK9 and LV-PCSK9 shRNA for PCSK9 overexpression and PCSK9 silencing. RESULTS: Immunohistochemical analysis showed that PCSK9 expression increased within atherosclerotic plaques in apoE KO mice. These in vivo results showed that the LV-PCSK9 shRNA group of mice developed less aortic atherosclerotic plaques compared with the control group. These lesions also had the reduced number of macrophages and decreased expression of vascular inflammation regulators, such as tumor necrosis factor-α, interleukin 1 beta, monocyte chemoattractant protein-1, toll-like receptor 4 and nuclear factor kappa B (NF-κB). We further showed that PCSK9 overexpression in macrophages in vitro increased the secretion of oxLDL-induced proinflammatory cytokines. PCSK9 overexpression upregulated TLR4 expression and increased p-IκBα levels, IkBα degradation, and NF-κB nuclear translocation in macrophages, but PCSK9 knockdown had the opposite effects in oxLDL-treated macrophages. CONCLUSIONS: PCSK9 gene interference could suppress atherosclerosis directly through decreasing vascular inflammation and inhibiting the TLR4/NF-κB signaling pathway without affecting plasma cholesterol level in high-fat diet-fed apoE KO mice. PCSK9 may be an inflammatory mediator in the pathogenesis of atherosclerosis.
Assuntos
Aorta/enzimologia , Doenças da Aorta/enzimologia , Aterosclerose/enzimologia , Mediadores da Inflamação/metabolismo , Inflamação/enzimologia , NF-kappa B/metabolismo , Pró-Proteína Convertase 9/metabolismo , Receptor 4 Toll-Like/metabolismo , Animais , Aorta/patologia , Doenças da Aorta/genética , Doenças da Aorta/patologia , Aterosclerose/genética , Aterosclerose/patologia , Modelos Animais de Doenças , Predisposição Genética para Doença , Inflamação/genética , Inflamação/patologia , Lipoproteínas LDL/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/enzimologia , Masculino , Camundongos , Camundongos Knockout para ApoE , Fenótipo , Placa Aterosclerótica , Pró-Proteína Convertase 9/genética , Células RAW 264.7 , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de SinaisRESUMO
BACKGROUND: Hyperlipidemia is a risk factor for neurodegenerative diseases. Proprotein convertase subtilisin / Kexin type 9 (PCSK9) degrades hepatic low-density lipoprotein receptor (LDLR) to regulate lipid metabolism. It is unclear if PCSK9 plays a role in neurodegenerative diseases. OBJECTIVE: This study was designed to determine whether PCSK9 is crucial between hyperlipidemia and Alzheimer's disease. The interrelationship between PCSK9 and neuronal apoptosis was explored in PC12 cells in response to treatment with oxidized low-density lipoprotein (oxLDL). METHODS: Cultured PC12 cells were serum-starved and incubated with different concentrations of oxLDL for 24âh. Intracytoplasmic lipid droplets were observed by oil red O staining. Morphological assessment of apoptotic cells was performed using Hoechst 33258 staining and flow cytometry analysis. The expression of mRNA and protein was detected by reverse-transcription polymerase chain reaction (RT-PCR) and western blot analyses, respectively. Transfection of small interfering RNA (siRNA) into PC12 cells was conducted using HiperFect Transfection Reagent. Concentrations of Aß40 and Aß42 were detected by enzyme-linked immunosorbent assay (ELISA) kit. RESULTS: Intracellular lipid content, the number of apoptotic cells, and PCSK9 expression were increased in PC12 cells after oxLDL treatment. Transfection with PCSK9 siRNA reduced the oxLDL-induced apoptosis of PC12 cells. We further confirmed the involvement of Bcl-2/Bax-Caspase (9, 3) signaling pathway in the regulation of PC12 cells apoptosis.ß-Secretase 1, another target gene of PCSK9, was downregulated in PC12 cells in response to oxLDL treatment. Aß40 and Aß42 contents were also decreased. CONCLUSION: PCSK9 promotes oxLDL-induced PC12 cell apoptosis through the Bcl-2/Bax-Caspase 9/3 signaling pathway.
Assuntos
Apoptose/efeitos dos fármacos , Lipoproteínas LDL/farmacologia , Pró-Proteína Convertase 9/metabolismo , Transdução de Sinais/efeitos dos fármacos , Peptídeos beta-Amiloides/metabolismo , Análise de Variância , Animais , Caspases/metabolismo , Meios de Cultura Livres de Soro/farmacologia , Relação Dose-Resposta a Droga , Citometria de Fluxo , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Células PC12 , Fragmentos de Peptídeos/metabolismo , Pró-Proteína Convertase 9/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/farmacologia , Ratos , Transfecção , Proteína X Associada a bcl-2/metabolismoRESUMO
Hyperlipidemia is a risk factor for Alzheimer's disease (AD) and other neurodegenerative diseases. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a lipid regulatory gene involved in cell apoptosis. However, the function and mechanism of PCSK9 in neuronal apoptosis following hyperlipidemia remains to be elucidated. The present study established a hyperlipidemic mouse model by feeding a highfat diet (HFD) to 6weekold apoE(/) mice. Plasma lipid levels, hippocampal lipid accumulation, hippocampal histology, and hippocampal neuronal apoptosis were all monitored for changes. The expression levels of PCSK9, ßsecretase 1 (BACE1), Bcell lymphoma 2 (Bcl2), Bcl2associated X protein (Bax), and caspase3 in hippocampal CA3 and CA1 neurons were also measured. Results demonstrated that a HFD increased the lipid accumulation in the CA3 hippocampus and the levels of plasma lipids, including triglycerides, total cholesterol, lowdensity lipoprotein, and highdensity lipoprotein. In addition, CA3 neurons in the HFD group indicated apparent injuries and increased neuronal apoptosis, which are associated with the expression of Bcl2, Bax, and caspase3. A HFD also increased the expression levels of PCSK9 and BACE1. BACE1 promotes cleavage of amyloid precursor proteins to generate ßamyloid peptide (Aß), which induces neuronal apoptosis. Protein levels of Aß are associated with the observation of amyloid plaques in the hippocampus of the HFD group. The results suggest that hyperlipidemia regulates neuronal apoptosis by increasing PCSK9 and BACE1 expression. Overall, the current study may elucidate the role of lipid metabolism disorder in AD pathogenesis.
Assuntos
Apolipoproteínas E/genética , Apoptose/genética , Regulação da Expressão Gênica , Hiperlipidemias/fisiopatologia , Neurônios/metabolismo , Pró-Proteína Convertase 9/genética , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Apolipoproteínas E/deficiência , Caspase 3/metabolismo , Colesterol/sangue , Dieta Hiperlipídica , Hipocampo/citologia , Hipocampo/metabolismo , Hiperlipidemias/metabolismo , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Neurônios/citologia , Pró-Proteína Convertase 9/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Triglicerídeos/sangue , Proteína X Associada a bcl-2/metabolismoRESUMO
Tet methylcytosine dioxygenase 2 (TET2) mediates the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). The loss of TET2 is associated with advanced atherosclerotic lesions. Our previous study showed that TET2 improves endothelial cell function by enhancing endothelial cell autophagy. Accordingly, this study determined the role of TET2 in atherosclerosis and potential mechanisms. In ApoE-/- mice fed high-fat diet, TET2 overexpression markedly decreased atherosclerotic lesions with uniformly increased level of 5hmC and decreased level of 5mC in genomic DNA. TET2 overexpression also promoted autophagy and downregulated inflammation factors, such as vascular cell adhesion molecule 1, intercellular adhesion molecule 1, monocyte chemotactic protein 1, and interleukin-1. Consistently, TET2 knockdown with small hairpin RNA (shRNA) in ApoE-/- mice decreased 5hmC and increased 5mC levels in atherosclerotic lesions. Meanwhile, autophagy was inhibited and atherosclerotic lesions progressed with an unstable lesion phenotype characterized by large lipid core, macrophage accumulation, and upregulated inflammation factor expression. Experiments with the cultured endothelial cells revealed that oxidized low-density lipoprotein (ox-LDL) inhibited endothelial cell autophagy. TET2 shRNA strengthened impaired autophagy and autophagic flux in the ox-LDL-treated endothelial cells. TET2 overexpression reversed these effects by decreasing the methylation level of the Beclin 1 promoter, which contributed to the downregulation of inflammation factors. Overall, we identified that TET2 was downregulated during the pathogenesis of atherosclerosis. The downregulation of TET2 promotes the methylation of the Beclin 1 promoter, leading to endothelial cell autophagy, impaired autophagic flux, and inflammatory factor upregulation. Upregulation of TET2 may be a novel therapeutic strategy for treating atherosclerosis.
Assuntos
Apolipoproteínas E/genética , Aterosclerose/genética , Aterosclerose/metabolismo , Autofagia/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , 5-Metilcitosina/análogos & derivados , Animais , Apolipoproteínas E/deficiência , Aterosclerose/patologia , Citocinas/metabolismo , Metilação de DNA , Dioxigenases , Modelos Animais de Doenças , Expressão Gênica , Regulação da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Imuno-Histoquímica , Mediadores da Inflamação/metabolismo , Lipoproteínas LDL/metabolismo , Masculino , Camundongos , Camundongos Knockout , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/patologiaRESUMO
MicroRNAs are a group of endogenously small non-coding RNA molecules that downregulate gene expression at the post-transcriptional level through binding to the 3'UTR of target mRNAs. Recent findings have revealed a key role for microRNAs in the pathophysiological processes of atherosclerosis. As a complex disease, atherosclerosis is influenced by a combination of multiple genes and environmental factors. Both of them play a role in atherogenesis by affecting different types of cells (such as endothelial cell, vascular smooth muscle cell and monocyte/macrophage) function. MicroRNAs control the senescence and dysfunction of endothelial cells, proliferation and migration of vascular smooth muscle cells, and macrophage-driven cytokine production and polarization. By these effects, microRNAs can influence the processes of atherosclerosis and may represent new molecular targets for therapy.
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Aterosclerose/genética , MicroRNAs/fisiologia , Células Endoteliais/patologia , Humanos , Macrófagos/patologia , Terapia de Alvo Molecular/métodos , Músculo Liso Vascular/patologiaRESUMO
Cardiovascular disease is a growing major global public health problem. Oxidative stress is regarded as one of the key regulators of pathological physiology, which eventually leads to cardiovascular disease. However, mechanisms by which FGF-2 rescues cells from oxidative stress damage in cardiovascular disease is not fully elucidated. Herein this study was designed to investigate the protective effects of FGF-2 in H2O2-induced apoptosis of H9c2 cardiomyocytes, as well as the possible signaling pathway involved. Apoptosis of H9c2 cardiomyocytes was induced by H2O2 and assessed using methyl thiazolyl tetrazolium assay, Hoechst, and TUNEL staining. Cells were pretreated with PI3K/Akt inhibitor LY294002 to investigate the possible PI3K/Akt pathways involved in the protection of FGF-2. The levels of p-Akt, p-FoxO3a, and Bim were detected by immunoblotting. Stimulation with H2O2 decreased the phosphorylation of Akt and FoxO3a, and induced nuclear localization of FoxO3a and apoptosis of H9c2 cells. These effects of H2O2 were abrogated by pretreatment with FGF-2. Furthermore, the protective effects of FGF-2 were abolished by PI3K/Akt inhibitor LY294002. In conclusion, our data suggest that FGF-2 protects against H2O2-induced apoptosis of H9c2 cardiomyocytes via activation of the PI3K/Akt/FoxO3a pathway.
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Apoptose/efeitos dos fármacos , Fator 2 de Crescimento de Fibroblastos/fisiologia , Proteína Forkhead Box O3/metabolismo , Peróxido de Hidrogênio/toxicidade , Miócitos Cardíacos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Proteína 11 Semelhante a Bcl-2/metabolismo , Linhagem Celular , Fosforilação , Transporte Proteico , RatosRESUMO
Neuronal apoptosis is crucial in neurodegenerative diseases. However, a lower apoptotic rate of nerve cells is detected in the brain compared to that in other organs in neurodegenerative patients or in animal models, suggesting that neuronal apoptosis induced by any type of risk factors is intricately regulated. Human and animal studies demonstrated that a high concentration of oxidized LDL (ox-LDL) in the brain, which is associated with hyperlipidemia, is one of the key apoptosis inducers in neurodegenerative diseases. However, the mechanism underlying the ox-LDL-mediated regulation of neuronal apoptosis has not been fully elucidated. Recently, we investigated proprotein convertase subtilisin/kexin type 9 (PCSK9), a striking gene involved in lipid metabolism that exhibits a positive correlation with macrophage and endothelial cell apoptosis induced by ox-LDL. Moreover, PCSK9 may degrade ß-site amyloid precursor protein-cleaving enzyme 1 (BACE1), the key enzyme cleaving amyloid precursor protein (APP) to generate amyloid ß peptide (Aß). Aß is another key apoptosis inducer in neurodegenerative diseases. Our findings indicated that PCSK9 may be upregulated by the high levels of ox-LDL in the brain associated with hyperlipidemia and promote neuronal apoptosis through the NF-κB-B-cell lymphoma 2 (Bcl-2)/Bax-caspase 9-caspase 3 signaling pathways. Moreover, increased PCSK9 levels may inhibit the APP/Aß metabolic pathway and reduce Aß generation by degrading BACE1, thereby decreasing Aß-induced neuronal apoptosis. The dual regulation mechanism of PCSK9 on apoptosis maintains neuronal apoptosis induced by risk factors at low levels.
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Angiogenic stimulation is a promising new strategy for treating patients with arteriosclerotic coronary artery disease. This strategy aims to ameliorate cardiac function by improving myocardial perfusion and lowering the risk of myocardial infarction. However, angiogenesis may contribute to the growth of atherosclerotic lesions. Atherogenesis is also a potential side effect of angiogenic therapy. Early clinical trials were performed using fibroblast growth factor 2 (FGF2) protein, which enhances the formation of new collateral vessels to reduce ischaemic symptoms. Conversely, angiogenic stimulation by FGF2 is a dilemma because it could cause negative angiogenic effects, such as atherosclerosis. Thus far, clinical trials in patients with recombinant FGF2 protein therapy have not yet yielded undisputable beneficial effects. Future trials should determine whether an improvement can be obtained in patients with coronary artery disease using a combination of FGF2 and other growth factors or a combination of the FGF2 gene and stem cell therapy. This review summarises the multiple roles of FGF2 in the progression of atherosclerosis, its effect on pro-angiogenesis and improvement of cardiac function in coronary artery disease, and the potentially unfavourable effect of angiogenesis on the prevention and treatment of atherogenesis.
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Doença da Artéria Coronariana/tratamento farmacológico , Doença da Artéria Coronariana/fisiopatologia , Fator 2 de Crescimento de Fibroblastos/uso terapêutico , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/fisiologia , HumanosRESUMO
Hydrogen sulfide (H(2)S) is the third endogenous signaling gasotransmitter, following nitric oxide and carbon monoxide. It is physiologically generated by cystathionine-γ-lyase, cystathionine-ß-synthase, and 3-mercaptopyruvate sulfurtransferase. H(2)S has been gaining increasing attention as an important endogenous signaling molecule because of its significant effects on the cardiovascular and nervous systems. Substantial evidence shows that H(2)S is involved in aging by inhibiting free-radical reactions, activating SIRT1, and probably interacting with the age-related gene Klotho. Moreover, H(2)S has been shown to have therapeutic potential in age-associated diseases. This article provides an overview of the physiological functions and effects of H(2)S in aging and age-associated diseases, and proposes the potential health and therapeutic benefits of H(2)S.
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Envelhecimento/metabolismo , Sistema Cardiovascular/efeitos dos fármacos , Sulfeto de Hidrogênio/metabolismo , Sulfeto de Hidrogênio/farmacologia , Sistema Nervoso/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fatores Etários , Animais , Sistema Cardiovascular/metabolismo , Humanos , Sulfeto de Hidrogênio/uso terapêutico , Sistema Nervoso/metabolismo , Estresse Oxidativo/efeitos dos fármacosRESUMO
The activation of endothelial cells by oxidized low-density lipoprotein (ox-LDL) with subsequent increases in endothelial permeability occurs in the early stage of atherosclerosis. Cathepsin L (CATL) is one of the cysteine proteases and has been implicated in advanced atherosclerotic lesions and plaque instability. This study aimed to explore the role of CATL in ox-LDL-induced early atherosclerotic events and to delineate the underlying mechanism. Results showed that ox-LDL upregulated CATL protein levels and activation in human umbilical vein endothelial cells (ECs) in a concentration-dependent manner and stimulated EC autophagy and apoptosis and increased EC monolayer permeability. Concomitantly, VE-cadherin expression was decreased. When ECs were pretreated with a CATL inhibitor, ox-LDL-induced autophagy was inhibited while apoptosis was further increased. In addition, the VE-cadherin protein level was increased, and the EC monolayer permeability was reduced. Taken together, the present study showed that the upregulated expression and activation of CATL induced by ox-LDL, increased EC autophagy and antagonized EC apoptosis, which partly neutralized the effect of increased EC monolayer permeability mediated by the downregulation of VE-cadherin. Thus, the proatherogenic effect of CATL was partly neutralized by inducing autophagy and inhibiting apoptosis in early stages of atherosclerosis.
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Catepsina L/metabolismo , Células Endoteliais/enzimologia , Lipoproteínas LDL/metabolismo , Antígenos CD/metabolismo , Apoptose/efeitos dos fármacos , Aterosclerose/tratamento farmacológico , Aterosclerose/enzimologia , Aterosclerose/genética , Aterosclerose/patologia , Autofagia/efeitos dos fármacos , Caderinas/metabolismo , Catepsina L/antagonistas & inibidores , Catepsina L/genética , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Ativação Enzimática , Células Endoteliais da Veia Umbilical Humana , Humanos , Permeabilidade/efeitos dos fármacos , Inibidores de Proteases/farmacologia , RNA Mensageiro/genética , Regulação para CimaRESUMO
Hydrogen sulfide (H(2)S), produced by cystanthionine-γ-lysase (CSE) in the cardiovascular system, has been suggested to be the third gasotransmitter in addition to nitric oxide (NO) and carbon monoxide (CO). The present study aimed to investigate the role of H(2)S in ischemic postconditioning (IPO) during the early period of reperfusion. IPO with 6 episodes of 10 sec reperfusion followed by 6 episodes of 10 sec ischemia (IPO 2') was administered when reperfusion was initiated. Cardiodynamics and the concentration of H(2)S were measured at 1, 2, 3, 4, 5, 10, 20, 30, 60, 90 and 120 min of reperfusion. Lactate dehydrogenase (LDH) levels and infarct size were determined at the end of the reperfusion. The concentration of H(2)S was stable during the whole experiment in the control group, whereas it reached a peak at the first minute of reperfusion in the ischemia-reperfusion (IR) group. The concentration of H(2)S at the first minute of reperfusion in the IPO 2' group was higher compared to that of the IR group, which correlated with cardioprotection including improved heart contractile function and reduced infarct size and LDH levels. However, the above effects of IPO 2' were attenuated by pre-treatment with blockade of endogenous H(2)S production with DL-propargylglycine for 20 min prior to global ischemia. Furthermore, we found that other forms of IPO, IPO commencing at 1 min after reperfusion (delayed IPO) or lasting only for 1 min (IPO 1'), failed to increase the concentration of H(2)S and protect the myocardium. We conclude that the peak of endogenous H(2)S in the early reperfusion phase is the key to cardioprotection induced by IPO.
RESUMO
This paper investigated the effects of ox-LDL on PCSK9, and the molecular mechanisms of PCSK9 siRNA-inhibited apoptosis induced by ox-LDL in human umbilical vein endothelial cells (HUVECs), to clarify the role of PCSK9 in atherosclerogenesis. HUVECs were incubated with ox-LDL for 24 h. The apoptosis was observed by Hoechst 33258 staining. The expression of PCSK9, LOX-1 mRNAs and proteins was detected by RT-PCR, western blot, respectively. The PCSK9 siRNAs labeled with fluorescence were transfected into HUVECs by Lipofectamine 2000. After transfection for 24 h, cells were treated with ox-LDL for 24 h, HUVECs apoptosis transfected siRNA was detected by Hoechst 33258 staining and flow cytometer. The expression of Bcl-2, Bax, caspase3, 8, 9 was detected by western blot. The activity of caspase3, 9 was detected by kits. Our results showed that apoptosis of HUVECs and the expressions of PCSK9 and LOX-1 were upregulated secondary to induction by ox-LDL in a concentration-dependent manner. However, ox-LDL-induced HUVEC apoptosis and PCSK9 expression, but not LOX-1 expression, were significantly reduced by PCSK9 siRNA. These results demonstrate a linkage between HUVEC apoptosis and PCSK9 expression. Furthermore, we detected the possible pathway involved in apoptotic regulation by PCSK9 siRNA; our results showed that the expression of Bcl-2 decreased, whereas that of Bax increased. In addition, ox-LDL enhanced the activity of caspase9 and then caspase3. Pretreatment of HUVECs with PCSK9 siRNA blocked these effects of ox-LDL. These findings suggest that ox-LDL-induced HUVECs apoptosis could be inhibited by PCSK9 siRNA, in which Bcl/Bax-caspase9-caspase3 pathway maybe was involved through reducing the Bcl-2/Bax ratio and inhibited the activation of both caspase9 and 3.
Assuntos
Proteínas Reguladoras de Apoptose/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/citologia , Lipoproteínas LDL/fisiologia , Pró-Proteína Convertases/genética , RNA Interferente Pequeno/farmacologia , Serina Endopeptidases/genética , Transdução de Sinais , Proteínas Reguladoras de Apoptose/fisiologia , Caspase 3 , Caspase 9 , Células Cultivadas , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Pró-Proteína Convertase 9 , Pró-Proteína Convertases/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2 , Proteína X Associada a bcl-2RESUMO
Cholesterol-loaded macrophage foam cells are a central component of atherosclerotic lesions. ATP binding cassette transporter A1 (ABCA1), the defective molecule in Tangier disease, mediates the efflux of phospholipid and cholesterol from cells to apolipoprotein A-I (apoA-I), reversing foam cell formation. This study investigated the effect of apoA-I on ABCA1 degradation and cholesterol efflux in THP-1 macrophage-derived foam cells. After exposure of the cultured THP-1 macrophage-derived foam cells to apoA-I for different time, cholesterol efflux, ABCA1 mRNA and protein levels were determined by FJ-2107P type liquid scintillator, RT-PCR and Western blot, respectively. The mean ABCA1 fluorescence intensity on THP-1 macrophage-derived foam cells was detected by flow cytometry. Results showed that apoA-I markedly increased ABCA1-mediated cholesterol efflux from THP-1 macrophage-derived foam cells. This was accompanied by an increase in the content of ABCA1. ApoA-I did not alter ABCA1 mRNA abundance. Significantly, thiol protease inhibitors increased the level of ABCA1 protein and slowed its decay in THP-1 macrophage-derived foam cells, whereas none of the proteosome-specific inhibitor lactacystin, other protease inhibitors, or the lysosomal inhibitor NH4Cl showed such effects. The apoA-I-mediated cellular cholesterol efflux was enhanced by thiol protease inhibitors. Our results suggested that thiol protease inhibitors might provide an alternative way to upregulate ABCA1 protein. This strategy is especially appealing since it may mimic the stabilizing effect of the natural ligands apoA-I.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Apolipoproteína A-I/farmacologia , Colesterol/metabolismo , Células Espumosas/efeitos dos fármacos , Células Espumosas/metabolismo , Transportador 1 de Cassete de Ligação de ATP , Linhagem Celular , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismoRESUMO
AIM: To study the effect of oxidized low density lipoprotein (ox-LDL) on ATP binding cassette transporter A1 (ABCA1) in THP-1 macrophages. METHODS: After exposing the cultured THP-1 macrophages to ox-LDL for different periods, cholesterol efflux was determined by FJ-2107P type liquid scintillator. ABCA1 mRNA and protein level were determined by reverse trancriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively. The cholesterol level in THP-1 macrophage foam cells was detected by high performance liquid chromatography. RESULTS: ox-LDL elevated ABCA1 in both protein and mRNA levels and increased apolipoprotein (apo) A-I-mediated cholesterol efflux in a time- and dose-dependent manner. 22(R)-hydroxycholesterol and 9-cis-retinoic acid did significantly increase cholesterol efflux in THP-1 macrophage foam cells (P<0.05), respectively. Both of them further promoted cholesterol efflux (P<0.01). As expected, liver X receptor (LXR) agonist decreased content of esterified cholesterol in the macrophage foam cells compared with control, whereas only a slight decrease of free cholesterol was observed. LXR activity was slightly increased by oxidized LDL by 12 % at 12 h compared with 6 h. However, LXR activity was increased about 1.8 times at 24 h, and oxidized LDL further increased LXR activity by about 2.6 times at 48 h. CONCLUSION: ABCA1 gene expression was markedly increased in cholesterol-loaded cells as a result of activation of LXR/RXR. ABCA1 plays an important role in the homeostasis of cholesterol in the macrophages.