Small Interfering RNA (siRNA) Therapy Using Kidney Targeting Nanoparticles for Treating Polycystic Kidney Disease

Background: ADPKD is the most prevalent genetic kidney disease in the world, affecting over 12 million people worldwide. It is characterized by the expansion of fluid-filled cysts that result in the development of enlarged kidneys and eventually kidney failure. Despite its prevalence, the sole FDA-approved therapy, Tolvaptan, offers only modest therapeutic relief. To address the need for precise therapeutic interventions in ADPKD, our study focuses on the development of kidney targeting nanoparticles that enable siRNA-mediated knockdown of ANO1 and MCP1, genes implicated in driving cystic fluid secretion and facilitating renal macrophage infiltration, for suppressing cyst growth. Methods: A collecting duct (CD) targeting peptide was conjugated to PEGylated lipids and collecting duct targeting peptide amphiphile micelles (CD-PAMs) were formed using thin-film hydration. The kidney targeting ability of CD-PAMs was analyzed using an ADPKD mouse model by flow cytometry and ex vivo organ imaging. Furthermore, CD-PAMs were loaded with siRNAs (CD-siRNA PAMs) and gene knockdown efficiency was tested on IMCD PKD1 KO cells using RT-qPCR and the impact of siRNA delivery on cyst growth was tested on a 3D cyst model. In addition, an ADPKD mouse model was used to evaluate the impact of CD-siRNA PAMs on kidney size and cystic index. Results: CD-PAMs exhibited higher kidney accumulation after 24 hours compared to the non-targeting PAMs (NT-PAMs) (45.9% vs 35.6% NP+ kidney cells, p=0.005). Moreover, flow cytometry analysis revealed the targeting nanoparticles exhibited a pronounced affinity for collecting duct cells relative to non-targeting nanoparticles (49.9% vs. 38.5% DBA+NP+ cells, p<0.001). In addition, CD-PAMs were effectively loaded with ANO1 and MCP1 siRNA (CD-siRNA PAMs), resulting in substantial gene knockdown rates of 76% and 66% in IMCD PKD1 KO cells, respectively. Notably, these interventions successfully suppressed cyst growth in a 3D cyst model, underscoring their therapeutic potential. Conclusion: We have successfully developed nanoparticles that can be functionalized with targeting peptides for increasing kidney accumulation. Furthermore, these nanoparticles can be loaded with small RNAs for manipulating gene expression and suppressing cyst growth in ADPKD. We are currently working to evaluate the therapeutic efficacy of our siRNA-loaded NPs in an ADPKD mouse model. Funding: Other U.S. Government Support