Regulation Of Lipid Metabolism In Liver Of Gansu Zokor(Eospalax Cansus)under Hypoxia Stress

Hypoxia stress research focuses on oxygen transport,and energy metabolism.A lot of research on energy metabolism under hypoxia stress involves glucose metabolism,but hypoxia lipid metabolism has become the focus of attention in the past 15 years.Lipids can be used for oxidative capacity,membrane synthesis,energy storage,and synthesis of signal molecules,which are critical to cell survival and proliferation.Studies have demonstrated that animals under low oxygen conditions can produce lipid metabolism disorders,and produce lipid metabolism disorders such as abnormal blood lipids.Gansu zokor(Eospalax cansus)is a good model of hypoxia adaptation as a subterranean rat.By studying the hypoxia lipid metabolism and its regulation in Gansu zokor,we can broaden the basic research of hypoxia tolerance lipid metabolism in ground rats,supplement the research content of hypoxia tolerance mechanism,and provide a new perspective for the treatment of related diseases such as lipid metabolism disorders.In order to elucidate the regulation of cholesterol(CHO)and fatty acid(FA)by the liver of Gansu zokor under hypoxia stress,we used adult health Gansu zokor and SD rats as experimental animals.1 8 rats of both Gansu zoker and SD rats,were randomly selected and divided into 3 groups(n=6).These 3 groups were tolerated with normal oxygen(2 1%O2,7 days),chronic hypoxia(10.5%O2,44 hours)and acute hypoxia(6.5%02.6 hours).Differential gene analysis was performed on the transcriptome data of the normoxic and acute hypoxia groups in Gansu zokor,and the pathways and genes related to lipid metabolism under hypoxia were screened.Differential gene analysis was performed on the transcriptome data of the normoxic and acute hypoxia groups in Gansu zokor,and the pathways and genes related to lipid metabolism under hypoxia were analyzed.RT-qPCR(Ldlr,Psck9,Scarbl,Cyp7al,Lrp5,Lrp6,Fasn,Hif-1,Accl,and Fabp3)and Weston Blot(LDLR,SCARB1,CYP7A1,LRP5,LRP6,FASN,and FABP3)were used to find the regulation of CHO and FA under hypoxia stress.Plasma lipids detection was used to find the changes of LDL-C,HDL-C,CHOL and TG under hypoxia stress.Immunohistochemistry(LDLR,SCARB 1,CYP7A1,LRP5,LRP6,FASN and FABP3)was utilized to study the protein distribution in the liver.Oil red-o staining was used to study the expression of TG in the liver.We also establish a navigation station and a crawler for analysing lipid metabolism related genes.Metabolic regulation of CHO and FA in liver of Gansu zokor was studied under hypoxia,comprehensively and systematically.The results demonstrate that:1.Transcriptome analysis with Gansu zokor liver showed that there were at least 270 pathways with differentially expressed genes between the acute hypoxia and normoxic groups.There are at least 17 pathways directly involved in the lipid metabolism.2.Changes in blood lipids of the Gansu zokor under normoxic and hypoxia conditions:Under normal and hypoxia conditions,the concentrations of LDL-C,HDL-C,and total cholesterol in the blood of Gansu zokor are higher than that of SD rats,7.19 times,3.92 times and 5.22 times than that of SD rats respectively.Gansu zokor under chronic hypoxia conditions:LDL-C and total cholesterol increased significantly,which were 8.44 times and 2.70 times than that of the normoxic group,respectively.HDL-C concentration increased,which was 1.86 times that of the normoxic group,but there was no significant difference(p=0.11).3.Gansu zokor lipid metabolism regulating gene expression:1)CHO transport and degradationUnder chronic hypoxia conditions in Gansu zokor:the expression levels of Ldlr and Psck did not change significantly,and the expression level of LDLR was up-regulated,which was 1.28 times higher than that of normoxic group,indicating that the liver recovered LDL-C.Scarbl was not expressed at the level of transcription and protein levels,and the liver recovery HDL-C channel was closed.Cyp7al was significantly down-regulated at the level of transcription and protein,which are 0.15 times and 0.37 times of normoxic group respectively,indicating reduced degradation of CHO.Under acute hypoxia conditions in Gansu zokor:the expression levels of Ldlr and Psck9 were down-regulated simultaneously,which are 0.70 times and 0.21 times of normoxic group respectively,and expressions of Scarbl and Cyp7a1 were up-regulated,which are 1.49 times and 2.20 times of normoxic group respectively.LDLR and SCARB1 expression levels were not significantly changed at the translation level,and CYP7A1 expression was down-regulated,which is 0.63 times of normoxic group.Indicating that CHO degradation was weakened.Under chronic hypoxia conditions in SD rats,LDLR expression was up-regulated and SCARB1 expression was down-regulated,which is 0.52 times of normoxic group.indicating that LDL-C recovery was enhanced and HDL-C recovery was weakened;under acute hypoxia conditions,LDLR,SCARBI,and CYP7A1 were all up-regulated,indicating LDL-C HDL-C recovery is enhanced and degradation of CHO is enhanced.2)Transport of Wnt pathway to CHOUnder chronic hypoxia conditions:Lrp5 expression was down-regulated but not significant at the transcription level in Gansu zokor,Lrp6 expression was significantly up-regulated,which is 2.42 times of normoxic group.LRP5 expression was significantly down-regulated at the transcription level,LRP6 expression was not changed,and LDL-C uptake was generally reduced.Under acute hypoxia conditions:Gansu zokor decreased the expression level of Lrp5 at the transcription level,which is 0.35 times of normoxic group,and there was no significant change in the expression level of Lrp6.The translation level of LRP5 was down-regulated,which is 0.72 times of normoxic group,and there was no change in LRP6,which reduced the uptake of blood LDL-C and showed no signs of abnormal metabolism in the Wnt pathway.Lrp5 and Lrp6 of SD rats increased to varying degrees under chronic hypoxia and acute hypoxia conditions,increased blood LDL-C uptake,increased Wnt pathway expression,and increased carcinogenic risk.3)FA synthesis and transportGansu zokor under chronic hypoxia conditions:Fasn and Accl expression are down-regulated at transcription level,which is 0.47 times of normoxic group.FASN expression is down-regulated at the translation level,which is 0.19 times of normoxic group.FA synthesis ability is decreased.FABP3 is up-regulated,which is 1.54 times of normoxic group,and FA transport capacity is increased.Acute hypoxia conditions:transcription levels Accl and Fasn are significantly down-regulated,which are 0.30 times and 0.44 times of normoxic group respectively.Fabp3 was significantly up-regulated,which is 5.24 times of normoxic group.FASN was down-regulated at the translation level,which is 0.19 times of normoxic group,and FABP3 was oppositely expressed at the transcription level,showing a down-regulation,which is 0.63 times of normoxic group,and its ability to synthesize and transport FA decreased.In SD rats,the transcription levels of Accl and Fasn were significantly up-regulated under hypoxia conditions,and the overall performance was to up-regulate FA synthesis.The livers of Gansu zokor and SD rats did not accumulate lipid droplets under hypoxia conditions.4.Protein localizationThe protein localization in Gansu zokor and SD rats is basically the same.Among them,LDLR,SCARB1,LRP5,LRP6,FABP3 and other transporters are distributed in vascular endothelial cells,and SCARB1,LRP5 and FABP3 are also distributed in the cytoplasm.CYP7A1 and FASN are cytoplasmic distribution.5.Typecho was used to build a lipid metabolism-related gene bioinformatics analysis navigation station,and Python was used to write a web crawler to automate the lipid metabolism-related genes bioinformatics analysis in this study.The navigation station and the web crawler are also suitable for other genes.The main conclusions are:1.Gansu zokor responds actively and extensively to hypoxia stress.There are 270 pathways with gene enrichment between the acute hypoxia and normoxia groups,and 17 pathways are directly involved in lipid synthesis and transport.2.Under normal and hypoxia conditions,the concentrations of LDL-C,HDL-C and total cholesterol in the blood of Gansu zokor are higher than those of SD rats in different degrees,showing hyperlipidemia.Gansu zokor's liver mainly regulates blood cholesterol under chronic hypoxia conditions.By down-regulating SC ARBI expression,it reduces HDL lipid recovery in the liver and indirectly promotes HDL-C transfer to LDL to increase LDL-C.By down-regulating CYP7A1,it reduces cholesterol degradation.By reducing HDL-C recovery and reducing cholesterol degradation,thereby increasing blood LDL-C and total cholesterol,it is concluded that there is a hypoxia adaptation in Gansu zokor that responds to hypoxia stress with hyperlipidemia.3.Under chronic hypoxia and acute hypoxia conditions,Gansu zokor down-regulates LRP5 to reduce blood cholesterol uptake,avoid abnormal activation of the Wnt signaling pathway,and increase the risk of canceration.Up-regulating Lrp5 and Lrp6 in SD rats under hypoxia conditions increase the risk of canceration.4.Under hypoxia stress,Gansu zokor down-regulated Accl and Fasn to reduce fatty acid synthesis in the liver.Under chronic hypoxia conditions,up-regulate FABP3 expression and enhance blood fatty acid uptake;under acute hypoxia conditions,down-regulate FABP3 expression and reduce blood fatty acid uptake.Studying how Gansu zokor copes with the adverse effects of hyperlipidemia and the study of hypoxia lipid metabolism response mechanism in Gansu zokor will help us better understand hypoxia and lipid metabolism,and may provide a new direction for the treatment of lipid metabolism diseases.