A Study of Characteristics and Key Genes Expression Patterns of Sheep Adipocytes in Dedifferentiation and Induced Redifferentiation State
The aim of this experiment was to investigate the differences in dedifferentiation mechanisms and in-duction redifferentiation abilities of sheep adipocytes.The optimized'ceiling'culture method was utilized to examine the dedifferentiation ability of adipocytes derived from different months of age and tissue sources,as well as the cell morphology and expression of key genes during dedifferentiation.Additionally,the induced li-pogenic redifferentiation ability of dedifferentiated fat(DFAT)cells from different tissue sources were com-pared.The results showed as follows:if adipocytes were not screened using cell screens with different mesh si-zes,there were no significant differences in the dedifferentiation time among adipocytes originating from same tissue but different months of age(P>0.05);there were no significant differences in dedifferentiation time be-tween tail adipocytes and perirenal adipocytes within the same month of age(P>0.05),but both significantly longer than intramuscular adipocytes(P<0.01).If adipocytes were screened into cell groups of different sizes,the dedifferentiation time for both tail adipocytes and intramuscular adipocytes with a diameter less than 300 mesh cell sieve apertures was significantly shorter than that with a diameter greater than 300 mesh cell sieve ap-ertures(P<0.01),the dedifferentiation time for tail adipocytes with a diameter larger than 200 mesh cell sieve apertures was significantly longer than that with diameters ranging between 200 and 300 mesh cell sieve aper-tures(P<0.01).So,it was confirmed that the time of adipocyte dedifferentiation was related to their size rath-er than their tissue source.After the dedifferentiation of adipocytes,large lipid droplets in cells gradually frag-mented into smaller ones,accompanied by significant upregulation of genes related to lipid synthesis and de-composition processes(P<0.01),and significant increase in triglyceride content detected in the cell medium(P<0.01),while the free fatty acid content also showed a significant increase but keep stable throughout all stages of dedifferentiation(P<0.05),so it was inferred that during the cell dedifferentiation,adipocytes may primarily eliminate lipids from cells by directly expelling lipid droplets.With the dedifferentiation of adipo-cytes,the expression of marker genes for adipocyte progenitor cells and preadipocytes,as well as stem cell marker genes were significantly upregulated(P<0.01),which indicated that adipocytes reversed their cellular fate determination and regained stem cell characteristics.The induced lipogenic redifferentiation ability of DFAT cells from different tissue sources showed no significant difference(P>0.05).In conclusion,the dedif-ferentiation capacity of sheep adipocytes is strongly correlated with their cell size but not with tissue source and age.Adipocyte dedifferentiation mainly involves clearing intracellular lipids by expelling lipid droplets and ac-quiring stem cell characteristics,however,the ability of DFAT cells to induce lipogenic redifferentiation is not influenced by their tissue source.[Chinese Journal of Animal Nutrition,2024,36(7):4638-4653]