目的:探讨肝脏中lamp2a对plin5表达及其功能的影响。方法:利用Western blot及免疫组化检测正常人和脂肪肝患者肝脏中lamp2a与plin5表达相关性。利用HepG2细胞构建lamp2a敲减的细胞系HepG2-L2A,通过给予油酸刺激、溶酶体抑制剂处理等进...目的:探讨肝脏中lamp2a对plin5表达及其功能的影响。方法:利用Western blot及免疫组化检测正常人和脂肪肝患者肝脏中lamp2a与plin5表达相关性。利用HepG2细胞构建lamp2a敲减的细胞系HepG2-L2A,通过给予油酸刺激、溶酶体抑制剂处理等进一步在细胞水平证实其相关性。结果:Western-Blot及免疫组化检测显示脂肪肝患者肝组织中lamp2a的表达明显下降,而plin5表达显著升高。Western-Blot试验提示正常培养的HepG2-L2A细胞中plin5表达较HepG2细胞中升高,Bodipy染色提示HepG2-L2A细胞中脂滴数量也明显增加(124±15.3 vs 273±19.1)。在分解试验中,HepG2细胞中plin5明显降低,脂滴数量也明显减少(282±24.1 vs 192±17.5);而HepG2-L2A细胞中plin5仍然处于高水平,脂滴数量仍然较多(325±24.0 vs 286±28.7)。当给予溶酶体抑制剂处理时,HepG2细胞中plin5降解明显抑制,而HepG2-L2A中plin5水平未见明显改变。结论:肝脏中lamp2a的异常表达影响plin5的表达,进而影响了脂质的分解。展开更多
脂滴包被蛋白5(perilipin5,Plin5)在脂肪酸氧化程度较高的组织中表达,虽然在细胞和动物模型中均发现Plin5具有促进脂滴堆积、提高线粒体功能和缓解脂毒性的作用,但Plin5如何发挥其功能特点的具体机制尚未得到分析整合。通过分析相关文...脂滴包被蛋白5(perilipin5,Plin5)在脂肪酸氧化程度较高的组织中表达,虽然在细胞和动物模型中均发现Plin5具有促进脂滴堆积、提高线粒体功能和缓解脂毒性的作用,但Plin5如何发挥其功能特点的具体机制尚未得到分析整合。通过分析相关文献发现:Plin5可以通过和CGI-58(comparative gene identification-58)结合来调节关键脂解酶脂肪甘油三酯水解酶(adiposetiglyceridelipase,ATGL)以调控脂肪的代谢过程;通过核转位与沉默信息调节因子2相关酶1(silent mating type information regulator 2homolog 1,SIRT1)和过氧化物酶体增殖物激活受体γ辅激活因子1α(PPARγcoactivator-1α,PGC-1α)结合促进线粒体功能基因的表达,提高线粒体的氧化能力和呼吸功能;通过增加围脂滴线粒体的含量促使脂滴含量增加并增强线粒体功能,这揭示了Plin5参与调节脂代谢和线粒体功能的具体机制。而耐力运动锻炼会显著增加Plin5的含量,表明Plin5是解释"运动员悖论"现象的关键因子,这为Plin5作为新的2型糖尿病治疗靶点提供了理论依据。展开更多
Objective:To investigate the regulatory mechanism in liver fibrosis progression by nuclear receptor of farnesoid X receptor(FXR)and the lipid droplet-associated protein of perilipin 5(PLIN5).Methods:FXR response eleme...Objective:To investigate the regulatory mechanism in liver fibrosis progression by nuclear receptor of farnesoid X receptor(FXR)and the lipid droplet-associated protein of perilipin 5(PLIN5).Methods:FXR response element(FXRE)upstream of PLIN5 gene was found by bioinformatics,and confirmed by a dual luciferase reporter gene system;a hepatic fibrosis model based on human hepatic stellate cell LX-2 was established by induction of transforming growth factor-β1(TGF-β1);mRNA and protein levels ofα-smooth muscle actin(α-SMA)and collagen栺were measured by qPCR and Western blot after transient overexpression of FXR or PLIN5;Oil red O staining was used to study the formation of lipid droplets.Results:The promoter region of the PLIN5 gene contained a known reverse repeats-1(IR-1);the gene expression of PLIN5 in LX-2 cells was up-regulated after FXR activation(P<0.01);overexpression of PLIN5 promoted the formation of lipid droplets and significantly reduced the TGF-β1 induced fibrosis gene expression(P<0.05);FXR activation showed no effects on the inhibition of LX-2 cells activation.Conclusion:Overexpression of PLIN5 promotes the formation of lipid droplets and inhibits activation of LX-2 cells.FXR might bind to the FXRE site upstream of PLIN5 gene and regulate its gene expression.In summary,FXR may prevent liver fibrosis progression partially by regulating lipid droplet-associated protein of PLIN5.展开更多
This study investigated the neuroprotective effects of lactate in subarachnoid hemorrhage,a severe cerebrovascular disease that is commonly caused by arterial aneurysm rupture and has limited early treatment options.L...This study investigated the neuroprotective effects of lactate in subarachnoid hemorrhage,a severe cerebrovascular disease that is commonly caused by arterial aneurysm rupture and has limited early treatment options.Lactate,a metabolic byproduct,has been shown to have neuroprotective properties,including enhancing cerebral microcirculation and reducing intracranial pressure in acute brain injury patients.However,the protective mechanisms of lactate in subarachnoid hemorrhage remain unknown.In this study,we showed that lactate alleviates early brain damage in subarachnoid hemorrhage by promoting neuronal lipid synthesis and the formation of lipid droplets in astrocytes.In vivo experiments using a subarachnoid hemorrhage mouse model showed that lactate treatment significantly improved neurological scores,reduced brain inflammation,and promoted lipid droplet formation in astrocytes within 24 hours.Lactate treatment increased free fatty acids levels in the brain.The results suggest that astrocytes absorbed these free fatty acids and converted them into lipid droplets,thus reducing cellular lipotoxicity.Moreover,lactate enhanced the antiapoptotic capacity of astrocytes by upregulating the expression of PLIN5,a protein crucial for lipid droplet formation.The inhibition of lipid synthesis or lipid droplet formation counteracted the neuroprotective effects of lactate,indicating that lactate’s protective role is closely linked to lipid metabolism and lipid droplet formation.In vitro experiments on HT22 neuronal cells exposed to hemin-an agent used to simulate subarachnoid hemorrhage injury-demonstrated that lactate mitigated cellular damage by reducing lipid peroxidation and preserving mitochondrial membrane potential.Lactate treatment in HT22 cells and astrocytes also showed that inhibition of lipid synthesis or lipid droplet formation reversed its protective effects,further emphasizing the importance of lipid metabolism in the neuroprotective action of lactate.This study provides insights into the neuroprotective mechanisms of lactate in subarachnoid hemorrhage.It indicates that lactate plays a role in promoting lipid synthesis in neurons and enhancing lipid droplet formation in astrocytes,thus mitigating brain damage and improving cell survival.These findings suggest that lactate,through its regulation of lipid metabolism,could be a potential therapeutic agent for subarachnoid hemorrhage.展开更多
文摘目的:探讨肝脏中lamp2a对plin5表达及其功能的影响。方法:利用Western blot及免疫组化检测正常人和脂肪肝患者肝脏中lamp2a与plin5表达相关性。利用HepG2细胞构建lamp2a敲减的细胞系HepG2-L2A,通过给予油酸刺激、溶酶体抑制剂处理等进一步在细胞水平证实其相关性。结果:Western-Blot及免疫组化检测显示脂肪肝患者肝组织中lamp2a的表达明显下降,而plin5表达显著升高。Western-Blot试验提示正常培养的HepG2-L2A细胞中plin5表达较HepG2细胞中升高,Bodipy染色提示HepG2-L2A细胞中脂滴数量也明显增加(124±15.3 vs 273±19.1)。在分解试验中,HepG2细胞中plin5明显降低,脂滴数量也明显减少(282±24.1 vs 192±17.5);而HepG2-L2A细胞中plin5仍然处于高水平,脂滴数量仍然较多(325±24.0 vs 286±28.7)。当给予溶酶体抑制剂处理时,HepG2细胞中plin5降解明显抑制,而HepG2-L2A中plin5水平未见明显改变。结论:肝脏中lamp2a的异常表达影响plin5的表达,进而影响了脂质的分解。
文摘脂滴包被蛋白5(perilipin5,Plin5)在脂肪酸氧化程度较高的组织中表达,虽然在细胞和动物模型中均发现Plin5具有促进脂滴堆积、提高线粒体功能和缓解脂毒性的作用,但Plin5如何发挥其功能特点的具体机制尚未得到分析整合。通过分析相关文献发现:Plin5可以通过和CGI-58(comparative gene identification-58)结合来调节关键脂解酶脂肪甘油三酯水解酶(adiposetiglyceridelipase,ATGL)以调控脂肪的代谢过程;通过核转位与沉默信息调节因子2相关酶1(silent mating type information regulator 2homolog 1,SIRT1)和过氧化物酶体增殖物激活受体γ辅激活因子1α(PPARγcoactivator-1α,PGC-1α)结合促进线粒体功能基因的表达,提高线粒体的氧化能力和呼吸功能;通过增加围脂滴线粒体的含量促使脂滴含量增加并增强线粒体功能,这揭示了Plin5参与调节脂代谢和线粒体功能的具体机制。而耐力运动锻炼会显著增加Plin5的含量,表明Plin5是解释"运动员悖论"现象的关键因子,这为Plin5作为新的2型糖尿病治疗靶点提供了理论依据。
基金National Natural Science Foundation of China(81973376)。
文摘Objective:To investigate the regulatory mechanism in liver fibrosis progression by nuclear receptor of farnesoid X receptor(FXR)and the lipid droplet-associated protein of perilipin 5(PLIN5).Methods:FXR response element(FXRE)upstream of PLIN5 gene was found by bioinformatics,and confirmed by a dual luciferase reporter gene system;a hepatic fibrosis model based on human hepatic stellate cell LX-2 was established by induction of transforming growth factor-β1(TGF-β1);mRNA and protein levels ofα-smooth muscle actin(α-SMA)and collagen栺were measured by qPCR and Western blot after transient overexpression of FXR or PLIN5;Oil red O staining was used to study the formation of lipid droplets.Results:The promoter region of the PLIN5 gene contained a known reverse repeats-1(IR-1);the gene expression of PLIN5 in LX-2 cells was up-regulated after FXR activation(P<0.01);overexpression of PLIN5 promoted the formation of lipid droplets and significantly reduced the TGF-β1 induced fibrosis gene expression(P<0.05);FXR activation showed no effects on the inhibition of LX-2 cells activation.Conclusion:Overexpression of PLIN5 promotes the formation of lipid droplets and inhibits activation of LX-2 cells.FXR might bind to the FXRE site upstream of PLIN5 gene and regulate its gene expression.In summary,FXR may prevent liver fibrosis progression partially by regulating lipid droplet-associated protein of PLIN5.
基金National Nature Science Foundation of China,No.81870944(to FL).
文摘This study investigated the neuroprotective effects of lactate in subarachnoid hemorrhage,a severe cerebrovascular disease that is commonly caused by arterial aneurysm rupture and has limited early treatment options.Lactate,a metabolic byproduct,has been shown to have neuroprotective properties,including enhancing cerebral microcirculation and reducing intracranial pressure in acute brain injury patients.However,the protective mechanisms of lactate in subarachnoid hemorrhage remain unknown.In this study,we showed that lactate alleviates early brain damage in subarachnoid hemorrhage by promoting neuronal lipid synthesis and the formation of lipid droplets in astrocytes.In vivo experiments using a subarachnoid hemorrhage mouse model showed that lactate treatment significantly improved neurological scores,reduced brain inflammation,and promoted lipid droplet formation in astrocytes within 24 hours.Lactate treatment increased free fatty acids levels in the brain.The results suggest that astrocytes absorbed these free fatty acids and converted them into lipid droplets,thus reducing cellular lipotoxicity.Moreover,lactate enhanced the antiapoptotic capacity of astrocytes by upregulating the expression of PLIN5,a protein crucial for lipid droplet formation.The inhibition of lipid synthesis or lipid droplet formation counteracted the neuroprotective effects of lactate,indicating that lactate’s protective role is closely linked to lipid metabolism and lipid droplet formation.In vitro experiments on HT22 neuronal cells exposed to hemin-an agent used to simulate subarachnoid hemorrhage injury-demonstrated that lactate mitigated cellular damage by reducing lipid peroxidation and preserving mitochondrial membrane potential.Lactate treatment in HT22 cells and astrocytes also showed that inhibition of lipid synthesis or lipid droplet formation reversed its protective effects,further emphasizing the importance of lipid metabolism in the neuroprotective action of lactate.This study provides insights into the neuroprotective mechanisms of lactate in subarachnoid hemorrhage.It indicates that lactate plays a role in promoting lipid synthesis in neurons and enhancing lipid droplet formation in astrocytes,thus mitigating brain damage and improving cell survival.These findings suggest that lactate,through its regulation of lipid metabolism,could be a potential therapeutic agent for subarachnoid hemorrhage.
