The Expression Characteristics Of Crotonylation In The Process Of Pericyte Activation-Renal Interstitial Fibrosis

Background: Chronic kidney disease(CKD)is a common health concern which induce the loss of renal function,and a considerable proportion of cases eventually progress to end-stage renal disease(ESRD),a devastating condition that requires life long dialysis or kidney transplantation.As a result,CKD has become a major public health problem,which imposes enormous socioeconomic burdens on the affected individuals,families and societies.However,there has been no specific and effective therapy available to reduce the progression of chronic kidney disease.Renal interstitial fibrosis is a hallmark and common outcome across all kinds of progressive CKD.The process of renal fibrosis is characterized by peritubular capillary rarefaction and excessive deposition of extra cellular matrix in the interstitial compartment,leading to scar formation.It widely accepted that pericytes play a crucial role in stabilizing the microvasculature in health,their detachment from the vascular wall and differentiation into myofibroblasts under pathological conditions not only leaves the vascular wall unprotected and vulnerable but also leads to interstitial fibrosis.So,we postulate that pericyte activation is a “hub”target to inhibit the progress of CKD.Lysine crotonylation is a newly discovered histone lysine modification.Recent evidence revealed that Kcr is involved in many biological processes through the regulation of chromatin remodeling,transcription,and gene expression.In addition,it participates in tumors,AIDS,heart failure and other organ injury.Specially,Kcr has a protect effect on acute kidney injury.However,the characteristic and role of Kcr in CKD remain unclear.Objective: To explore the characteristic of lysine crotonylation in pericyte activation during RIF.Methods: MACS was applied for primary mouse pericytes isolation and pericytes activation in vitro model was established by TGF-?1 induction.Immunofluorescence and Western blot were used to test the expression of myofibroblast biomarkers and the level of lysine crotonylation.Further,UUO 1d,3d,7d mice models were established.Masson,PAS were used to test the pathological changes of tubulointerstitium.In addition,immunofluorescence was used to test the change of pericytes,and myofibroblast and Kcr during renal fibrosis in vivo.Results: After 24 h of TGF-?1 induction,myofibroblast-like morphological changes were found in pericytes in vitro,along with significantly increased expression of PDGFR?,?-SMA and Kcr.Difference was statistically significant(P<0.05).UUO 1 day,a small amount of vacuolar degeneration of renal tubular epithelial cells appeared;UUO3 days,a large number of vacuole deformation appeared,accompanied by epithelial cells replacement and inflammatory cells infiltration;UUO 7 days,renal tubular structure was disordered and a large amount of collagen fibroids are deposited in the glomerular capillary cavity and renal interstitial space.Significantly increased expression of PDGFR?,?-SMA and pan-Kcr were observed in kidney tissues.Difference was statistically significant(P<0.05).Conclusion: Through in vivo and in vitro experimental studies,we found that the expression of Kcr increased in the process of pericytes activation during RIF.Kcr may play an important regulatory role in this process.And Kcr may be a potential new intervention target to inhibit RIF.Whether there is a regulatory effect between Kcr and pericytes activation and its mechanism need to be further studied.