| Autophagy is a lysosome-dependent degradation process,by which the cytoplasm is sequestered into double-membrane vesicles and delivered to the lysosome for breakdown and recycling of organelles or nutrients.Adipose tissues regulate glucose and lipid metabolism,and play an energy metabolism imbalance caused by obesity.Therefore,the study of autophagy in adipose cells / tissue may be a new target and idea for prevention and treatment of obesity.Objective To observe the expressions of autophagy-lysosome genes in obese fat and the effect of autophagy-related protein survivin on adipocyte function.Methods 1.Omental adipose tissues from normal and obesity patients were used for RNA-sequence analysis,and the expression of 322 autophagy-lysosome genes were observed;Meanwhile differentially expressed genes were processed to KEGG enriched pathway analysis;Transcriptional profiling from GEO database was used to analyze the effect of TNFα on the expression of autophagy-lysosome genes;Then we measured autophagy core genes and p62 expression and autophagy flux after TNFα treatment in3T3-L1 adipocytes;our previous study preliminary found lipid droplets coated protein perilipin was degradated by autophagy,so this study further investigate the effects of TNFα and Berberine on perilipin protein degradation.2.Previous studies observed autophagy-related protein expression in different metabolic state in mice,this paper further examined the expression of autophagy-related protein survivin in adipose tissue of long(24w)and short-term(1w)high-fat diet mice;Separated SVF and mature adipocytes to observe survivin expression of cell-specific.Besides,we observed the expression of survivin in the differentiation process of 3T3-L1 adipocytes and C3H10T1 / 2 pluripotent stem cell.In addition,we used lentiviral virus overexpression survivin to study the effect of survivin on lipogenesis,lipolysis,and TNFα induced DNA damage and apoptosis inmature adipocytes,Then investigate whether survivin and emodin have similar functionsResults 1.In visceral adipose tissue of obesity,50 autophagy lysosome genes were statistically upregulated;while KEGG enrichment analysis identified TNF pathway most notably;Transcriptional profiling revealed the number of autophagy-lysosome genes were upregulated after TNFα treatment for2 h and 24h;Treated with TNFα for 4h,autophagy core protein were found upregulated and mRNA and protein expression of p62 / sqstm1 increased,meanwhile TNFα promoted perilipin autophagic degradation.2.As autophagy-related protein,survivin is expressed at low levels in terminally differentiated cells.Researches about survivin mainly focused on cancer,and study on survivin expression in adipose tissue / cells and adipocyte function regulation has never been reported.This study observed that survivin expression in mice fat was very low but high-fed-diet can induce re-expression of survivin in mouse adipose tissue;In 3T3-L1 adipocyte differentiation process,survivin expression was highest on second day and gradually reduced to almost undetectable on eighth day;similarly,in C3H10T1 / 2pluripotent stem cells,with directed differentiation into adipocytes,survivin expression gradually reduced;overexpression of survivin did not affect adipocyte differentiation,but it may promote cell proliferation and lipid synthesis,inhibit TNFα and ISO stimulated lipolysis,and also suppress TNFα-induced DNA damage and apoptosis in adipocytes.Conclusions The overactivation of autophagy in visceral adipose tissue in obese individuals may be closely related to inflammation,and inflammatory cytokines TNFαmay upregulate autophagy and p62 to promote lipid droplet coat protein perilipin selective autophagic degradation,enhance lipolysis;Autophagy-related protein survivin can be induced re-expression under conditions of over-nutrition,and it may inhibit chronic inflammation induced lipolysis,apoptosis and DNA damage,promote preadipocytes proliferation and newborn,suggesting that surviving may promote adipose tissues healthy expansion to main the whole body adipose tissue homeostasis and energy balance. |
