The Mechanism Of Foxol-inhibition Potentiated High-glucose And Palmitic Acid Induced β-cell Dedifferentiation

Diabetes is a major long-term disease,which has rapidly developed into a global issue in recent years,and has a significant impact on human society,health and economy.Among them,type 2 diabetes(T2D)is a complex multifactorial disease,accounting for about 90%of the total number of diabetic patients,which is characterized by insulin resistance in peripheral tissues and islet β-cell failure in the pancreas.Therefore,islet β-cell failure which secreting insulin plays a key role in the pathogenesis of T2D.Recent studies have shown that dedifferentiation is one of the main pathological factors of β-cell failure,but the underlying mechanisms remain unclear.So far,most studies of β-cell dedifferentiation have relied on rodent models and human pathological specimens.However,this type of experiment is poorly maneuverable and there are individual differences.Moreover,the mechanisms linking genetic factors and cellular stress to β-cell dedifferentiation remain largely unclear.Therefore,development of in vitro system can facilitate to dissect the underlying mechanism of β-cell dedifferentiation.In this study,we established an in vitro model of β-cell dedifferentiation induced by highglucose and palmitic acid using INS-1 832/13 cell line,and demonstrated that inhibiting Foxol can further enhance these phenomena.This phenomenon had also been verified in vivo experiments with zebrafish as a model organism.Furthermore,we performed RNA-seq of these stimulated cells,and the results showed that high-glucose and palmitic acid treatment significantly down-regulated the expression of β cell specific markers,and up-regulated the β-cell forbidden genes and endocrine precursor cell marker genes.We further analyzed enriched 546 differentially expressed genes that may be related to Foxol-inhibition reinforced β cells dedifferentiation,and the results showed that these genes were significantly enriched in metabolic pathway,MAPK pathway and PI3K-Akt pathway.In addition,the expression of endoplasmic reticulum stressrelated genes was significantly up-regulated under the stimulation of high-glucose and palmitic acid,and Foxol-inhibition could further amplify this difference.PPI network analysis indicated that endoplasmic reticulum stress-related gene Atf4 may be the hub gene that Foxol-inhibition reinforced β cells dedifferentiation induced by high glucose and palmitic acid,suggesting that βcell dedifferentiation may be related to endoplasmic reticulum stress.Subsequent experimental results proved that endoplasmic reticulum stress was the main reason for β-cell dedifferentiation caused by high-glucose and palmitic acid,and the transcription factor Foxol was involved in this process.The loss of Foxol can aggravate the endoplasmic reticulum stress caused by metabolic stress,thereby enhancing the dedifferentiation of β cell,and preventing the occurrence of endoplasmic reticulum stress can reduce β-cell dedifferentiation.In conclusion,we successfully constructed the model of β-cell dedifferentiation in vitro,and proposed that endoplasmic reticulum stress caused by glucose and lipid metabolism disorder is the driving factor of β-cell dedifferentiation,and transcription factor Foxol is the key factor of β-cell dedifferentiation which induced by endoplasmic reticulum stress.