WCN26-6310 A Case of Death Due to Rapidly Progressive Multiple Liver Tumors and Multiple Lung Tumors 13 Years After Living Donor Kidney Transplantation

Introduction: Nephronophthisis (NPH) is an autosomal recessive kidney ciliopathy and a major genetic cause of end-stage renal disease (ESRD) in children.The aberrant activation of the RhoA/ROCK signaling pathway is associated with the pathogenesis of various ciliopathies.In this study, we aimed to investigate the role of the RhoA/ ROCK signaling pathway in the pathogenesis of NPH1 caused by nphp1 gene defects.Methods: Nphp1 knockout MDCK cells and C57BL/6J mice were generated using CRISPR/Cas9 technology.The activity of ROCK was inhibited through in vitro transfection of siRNA and in vivo transfection of AAV vector, as well as the application of ROCK inhibitors, to evaluate the effects of ROCK inhibition in both in vitro and in vivo experiments.Cytochalasins D were used to directly inhibit the cytoskeleton to verify the role of the cytoskeleton in downstream pathways.The activation of the RhoA/ROCK pathway and the NF-B pathway was analyzed using quantitative real-time PCR, Western blotting, and immunohistochemistry.The pathological changes in the kidneys were evaluated using HE staining, Masson's staining, and immunohistochemistry.Results: The RhoA/ROCK pathway was overactivated in both nphp1KO MDCK cells and nphp1KO mice.The NF-B pathway was activated in the nphp1KO model, as evidenced by a significant increase in the phosphorylation levels of the key molecule P65.Inhibition of ROCK resulted in a significant suppression of NF-B activation.This suppression reduced the expression levels of downstream inflammatory factors, and led to a decrease in the population of M1-type renal macrophages in nphp1KO mice.Furthermore, ROCK inhibition effectively rescued the impaired ciliogenesis associated with nphp1 deficiency.Notably, direct inhibition of the cytoskeleton using cytochalasin B also successfully suppressed NF-B activation. Conclusion:The RhoA/ROCK pathway is aberrantly activated in both in vivo and in vitro models of nphp1 deficiency, mediating the activation of the NF-B inflammatory signaling pathway.ROCK inhibition can improve renal interstitial inflammation and fibrosis in nphp1KO mice, rescue cilia formation.Furthermore, the therapeutic effects of inhibiting the RhoA/ROCK pathway are achieved through the regulation of the cytoskeleton.I have no potential conflict of interest to disclose.I did not use generative AI and AI-assisted technologies in the writing process.