The Mechanism And The Effect Of PI16 On Adipogenesis In MSC

Background:At present,the proportion and prevalence of obesity patients in developed countries or China has become a serious public health problem,because obese patients often secondary to a variety of complications,such as cardiovascular disease,type 2 diabetes,hypertension and some cancers.Obesity is a chronic metabolic disease with increasing total adipose tissue content and(or)abnormal distribution in the body.In addition to storage and mobilization of energy,adipose tissue is also an important endocrine organ regulating the overall metabolic level.In addition to most mature fat cells in the adipose tissue,they also include macrophages,fibroblasts,mesenchymal stem cells(MSCS),and preadipocytes.All these cells are located in the stromal vascular fraction(SVF),in different adipose tissue,the vascular matrix part of the determination of the cell type and phenotype differences.the influence of genetic,environmental,diet and other factors,all can change the specific microenvironment of vascular matrix.Mesenchymal stem cells or progenitor cells in adipose tissue change the proliferation and differentiation potential.Adipocyte differentiation is also a complex multi-steps process involving a series of transcription factors that regulate the expression of key proteins and promote the development of fat cells.In recent years,with the rapid development of life science,the interpretation of development and disease mechanism is clearer.Especially found a new Transcription Peptidase Inhibitor 16(PI 16)in the adipose tissue,PI 16 has the regulation of extracellular matrix function and work as a transcription factor to participate in the expression of many genes.Therefore,we study the role of PI 16 in the differentiation of adipocytes,and provide a way to find new targets and mechanisms of obesity prevention and control,and may provide potential molecular targets for obesity and related metabolic diseases.Objective:1.Examination the expression situation of PI 16 in adipose-derived mesenchymal stem cells?induced differentiated adipocytes and high fat diet(HFD)induced obese mice.2.To observe the function of PI16 in HFD-induced mice.3.To observe the effect of overexpression of PI 16 on the differentiation of mesenchymal stem cells and explore the mechanism of inhibition in differentiation.Methods:1.Isolating primary human mesenchymal stem cells and rat primary mesenchymal stem cells from different parts of adipose tissues.Using classical"cocktail" program:insulin,dexamethasone,rosiglitazone(with the exception of 3T3-L1 cells),3-Isobutyl-l-Methylxanthine(IBMX)to induce the differentiation of preadipocytes into mature adipocytes,2.Using HFD-induced obese mice,We examined the expression situation of PI16 in subcutaneous?brown adipose tissue and visceral adipose tissue by Western Blotting.3.Mesenchymal stem cells were transfected with a Adenovirus over-expression PI 16 or empty virus for 48h before differentiation.After differentiated into mature adipocytes in vitro.Adipogenesis as confirmed by oil red O staining,cholesterol?triacylglycerol content.The expression levels of key genes(PPARy,C/EBP-?,Fas,ACC,FABP4)were detected by Western Blotting.Results:1.PI16 was decreased in differentiated MSC in the third day.2.PI16 showed low expression profile in different parts of adipose tissues by HFD-induced mice.3.Overexpression of PI 16 significantly inhibited lipid droplets as indicated by oil red O staining,and inhibited the expression of triacylglycerol,cholesterol content.4.Western Blotting analyses confirmed that the key of transcription factors:PPARy,C/EBP-adecreased significantly after transfected with the PI16-expressing adenovirus.5.Western Blotting analyses confirmed the marks of adipocytes:Fas,ACC,FABP4 decreased significantly after transfected with the PI16-expressing Adenovirus.6.Overexpression of PI16 inhibited the classical insulin signaling pathway by inhibiting the expression of PTEN and Akt.7.Overexpression of PI16 inhibited the expression of P38,enhanced the expression of ERK and JNK,and inhibited the role of adipocytes differentiation.Conclusion:1.PI16 was low expressed in HFD-Induced obesity models,indicating PI16 was closely related to obesity.2.PI16 significantly decreased HFD-induced body weight gain and improved carbohydrate metabolism.3.PI16 overexpression inhibited the differentiation of primary mesenchymal stem cells.4.PI16 inhibited the expression of the classical insulin signaling pathway by inhibiting the expression of PTEN and Akt.5.PI16 inhibited adipogenesis by decreased the expression of P38 and promoted the expression of ERK and JNK.