Truncated complement factor H Y402 gene therapy rescues C3 glomerulonephritis

There are no effective therapies for patients with dry age-related macular degeneration (AMD) or C3 glomerulonephritis (C3G). Unfortunately, past efforts to treat C3G using exogenous human complement factor H (CFH) found limited success due to immune rejection of a foreign protein response. AMD research has also faced myriad challenges, including the absence of an ideal therapeutic target and difficulties with treatment delivery in certain preclinical models. In pursuit of an AMD therapy to overcome these obstacles, we ultimately capitalized on parallels in complement dysregulation between AMD and C3G. Here, we investigate the potential for CFH supplementation as a strategy to rescue C3G. Our findings demonstrate restored inhibition of complement's alternative pathway and long-term reversal of disease without immune rejection using adeno-associated virus (AAV)-mediated delivery of truncated CFH (tCFH) in a Cfh^-/- mouse model of C3G. We tested three different tCFH vectors and found significant differences in their relative transduction efficiency and therapeutic efficacy. These discoveries motivate the development of AAV-mediated tCFH replacement therapy for patients with C3G while simultaneously demonstrating proof of concept for AAV-mediated tCFH gene augmentation therapy for patients with AMD.