Kidney Week

Abstract: SA-OR62

Early Intervention with Intravenous AAV9 Gene Therapy Significantly Improves Biomarkers and Phenotypes in a Floxed Mouse Model of X-linked Alport Syndrome

Session Information

• Glomerular Diseases: All about Podocytes
  October 26, 2024 | Location: Room 1, Convention Center
  Abstract Time: 05:40 PM - 05:50 PM

Category: Glomerular Diseases

• 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology

Authors

• Nakai, Hiroyuki, Oregon Health & Science University, Portland, Oregon, United States

Hiroyuki Nakai, MD, PhD

• Das, Ranjan, Oregon Health & Science University, Portland, Oregon, United States

Ranjan Das, PhD

• Furusho, Taisuke, Oregon Health & Science University, Portland, Oregon, United States

Taisuke Furusho, MD, PhD

• Sairavi, Anusha, Oregon Health & Science University, Portland, Oregon, United States

Anusha Sairavi, MS

• Hakui, Hideyuki, Oregon Health & Science University, Portland, Oregon, United States

Hideyuki Hakui, MD, PhD

• Luo, Shuhua, Oregon Health & Science University, Portland, Oregon, United States

Shuhua Luo, MS

• Li, Lena, Oregon Health & Science University, Portland, Oregon, United States

Lena Li, MD

• Miner, Jeffrey H., Washington University in St Louis School of Medicine, St Louis, Missouri, United States

Jeffrey H. Miner, PhD, FASN

Background

Previously, we established a novel floxed X-linked Alport syndrome (XLAS) mouse model. A delayed intervention with a higher dose of AAV-Cre (at 17 weeks of age) improved lifespan and reduced glomerulosclerosis and tubular injuries. Here, we report the results of an early intervention (before the onset of CKD) with a lower dose of AAV-Cre to these XLAS mice.

Methods

LSL-Col4a5 hemizygous male mice (n=3) were injected intravenously (IV) with 3.0 x 10¹¹ vg of the AAV9-CAG-Cre vector at 4 weeks of age. They were monitored for body weight, urinary albumin-to-creatinine ratio (ACR), and blood biomarkers of chronic kidney disease (CKD). Type IV collagen expression recovery was evaluated using immunofluorescence microscopy and kidney histology was examined in H&E-stained sections.

Results

AAV-injected mice, unlike the untreated counterparts, exhibited no discernible loss of body weight until 31 weeks of age, indicating therapeutic effects. Rescue of collagens was confirmed in one of the mice at 21 weeks post-injection. The vector-treated XLAS mice showed significant rescue of Col4a4 and Col4a5 proteins in the glomerular basement membrane using anti-Col4A4 and anti-Col4A5 antibodies. A non-injected LSL-Col4a5 hemizygous mouse was used as a negative control. There was a significant reduction in urinary ACR in the vector-treated group at 10 and 13 weeks post-injection compared to the untreated control. Notable decreases in blood creatinine (treated vs. untreated: 0.3 vs. 0.7 mg/dL, n=2) and BUN (treated vs. untreated: 47 vs. 129 mg/dL, n=2) were observed in the treated group. Kidney histology revealed a noticeable reduction in glomerulosclerosis, tubular atrophy and interstitial fibrosis. These results illustrated the successful transduction of podocytes by IV-injected AAV9 vectors in juvenile mice, preceding CKD onset.

Conclusion

This study highlights a crucial advantage of early intervention with a lower AAV dose in XLAS mice in reducing blood biomarkers of nephrotic syndrome, which was not observed in a delayed intervention strategy of AAV gene therapy. Thus, this study offers pioneering evidence of the efficacy of intravenous AAV vector-mediated gene therapy for Alport syndrome, especially notable for its effectiveness at pre-CKD establishment.