Diagnostic Value And Mechanism Of ACE And AP-N In Congenital Ureteropelvic Junction Obstruction

objectiveUreteropelvic junction obstruction(UPJO)is one common obstructive urinary tract disorder featured by featured by reduced urine flow from the renal pelvis to the ureter.Being untreated appropriately,the progression of UPJO could further result into hydronephrosis,urolithiasis,chronic renal infection,impaired renal function and even renal failure.But its pathogenic mechanisms remain largely unclear.This study aimed to investigate the potential involvement of the resin-angiotensin system(RAS)in congenital UPJO pathogenesis.MethodsThe differentially expressed proteins in exosomes isolated from amniotic fluids of congenital UPJO patients were characterized by isobaric tags for relative and absolute quantification(iTRAQ)based proteomics.ACE(angiotensin-converting enzyme)and AP-N(aminopeptidase N)expression in HK2 cells were inhibited by quinapril and siRNA respectively.Cell proliferation and reactive oxygen species levels were measured by EdU staining and flow cytometry respectively.Gene expression was detected by western blotting or qRT-PCR.Inflammatory factors were measured via ELISA.Mice underwent unilateral ureteral obstruction was used as the animal model.ResultsThe identity of exosomes from amniotic fluids were confirmed by the expression of CD9 and CD26.Totally 633 differentially expressed proteins were identified in amniotic fluid exosomes from UPJO patients,including 376 up-regulated and 257 down-regulated proteins associated with multiple biological processes.Among them,ACE and AP-N were significantly decreased in amniotic fluid exosomes.Inhibition of ACE and AP-N caused suppressed cell proliferation,repressed IARP,AT1R and MAS1 expression,elevated ROS production and increases of IL-1b,TNF-a and IL-6 in HK2 cells,Decreased ACE expression and elevated IL-1b content were also observed in mouse unilateral ureteral obstruction model.ConclusionThe suppression of ACE and AP-N expression mediated congenital UPJO pathogenesis by repressing renal tubular epithelial proliferation,promoting ROS production and enhancing inflammatory factor expression.