Recombinant Adeno-associated Virus Serotype 9 Vectors Combined With Improved Transparenchymal Renal Pelvis Injection For Renal Gene Delivery

Background: Polycystic kidney disease(PKD)is mainly divided into autosomal dominant polycystic kidney disease(ADPKD)and autosomal recessive polycystic kidney disease(ARPKD).Autosomal dominant polycystic kidney disease(ADPKD)is the most common hereditary nephropathy.The prevalence of this disease is between 1/400-1/1000.Patients with this disease are mostly in adulthood.According to reports,about 4-6 million people suffer from this disease in the world,and there are about 1.5 million patients of this disease in China.Polycystic kidney disease(PKD)can undergo some characteristic pathological changes due to mutations in related pathogenic genes,that is,bilateral kidneys will gradually form a large number of ellipsoidal or fusiform cysts,and constantly compress the normal renal parenchyma,and finally it causes the normal structure and physiological functions of the kidney to be destroyed,and thus develops into end-stage renal disease(ESRD).The main cause of ADPKD is mutation of type I polycystic kidney disease gene(PKD1 gene)and type II polycystic kidney disease gene(PKD2 gene),while the main cause of ARPKD is mutation of the fibroblast protein gene(PKHD1 gene).This causes abnormalities in the signaling pathways of renal epithelial cells.At present,in addition to kidney transplantation,there is no clinically recognized effective means or technology to completely cure polycystic kidney disease(PKD).Gene therapy is considered to be a potential therapeutic or approach for this disease.It is potentially valuable and meaningful that using gene delivery techniques to deliver a gene of interest to a genetically alteredorgan via a viral vector or a novel vector system,possibly in the treatment of polycystic kidney disease(PKD).Objective: To find effective gene delivery approach in kidney,we developed trans-parenchymal renal pelvis injection,a new route that combined renal intraparenchymal injection with renal pelvis injection.Methods: AAV9 vectors were injected into the mouse kidney by trans-parenchymal renal pelvis injection.Gene delivery efficiency was evaluated by living animal imaging,immunostaining and western blot analysis,while the safety of this procedure was also assessed simultaneously.Results: The exogenous gene was expressed in tubular epithelial cells of injected kidney,with much lower expression level in contralateral kidney.Extrarenal transfection in liver was also observed in this study.Renal and liver functions of AAV9 injected mice were comparable to those in mice without injection.Conclusions: Administration of AAV9 vectors by newly established trans-parenchymal renal pelvis injection achieved desired exogenous gene expression in the kidney and extrarenal transfection in a safe range,hence providing theoretical basis and alternative technical choice for gene therapy of renal diseases.