Abstract: FR-PO352

Lysyl Oxidase Like-2 Contributes to Alport Renal Disease Progression

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 308 CKD: Mechanisms of Tubulointerstitial Fibrosis

Authors

  • Cosgrove, Dominic E., Boystown National Resident Hospital, Omaha, Nebraska, United States
  • Meehan, Daniel T., Boys Town National Research Hospital, Omaha, Nebraska, United States
  • Dufek, Brianna M., Boys Town National Research Hospital, Omaha, Nebraska, United States
  • Delimont, Duane C., Boys Town National Research Hospital , Omaha, Nebraska, United States
  • Hartnett, Michael, Boys Town National Research Hospital , Omaha, Nebraska, United States
  • Mackenna, Deidre, PharmAkea, San Diego, California, United States
  • Bain, Gretchen, PharmAkea, Inc, San Diego, California, United States
Background

Lysyl oxidase like-2 (LOXL2) is thought to have both intracellular and extracellular functions. Extracellularly, LOXL2 performs the first step in the formation of crosslinks in collagen and elastin networks, resulting in increased stiffness which promotes the transition of fibroblasts to myofibroblasts. Intracellularly, LOXL2 modifies histones, stabilizes SNAIL, and reduces cell polarity which increases metastatic potential of tumors. LOXL2 promotes liver and lung fibrosis, but nothing is known regarding a role in the kidney. This study explored whether LOXL2 influences kidney disease in Col4a3(-/-) Alport mice.

Methods

LOXL2 protein and mRNA expression in WT versus Alport mice was examined. Alport mice were treated with a small molecule inhibitor (LOXL2i) or vehicle from 2 to 7 weeks of age. Both cortex and glomeruli were analyzed by real time PCR for genes associated with glomerular and interstitial disease, by immunofluorescence (IF) for collagen 1 and CD45 to assess interstitial fibrosis, by IF for fibronectin to score glomerulosclerosis , for mesangial filopodial invasion by IF for laminin α5 and integrin α8, and for albuminuria and BUN. TEM analysis was performed for ultrastructural analysis of the GBM. Lifespan was also assessed.

Results

LOXL2 protein and mRNA (>15-fold) are induced in Col4A3(-/-) Alport kidneys. LOXL2i-treatment significantly reduced interstitial fibrosis (by >50%) and mRNA expression for the fibrosis markers MMP-2, MMP-9, TBF-β1, and TNF-α in the interstitium. Additionally, LOXL2i treatment also reduced glomerulosclerosis (by >75%) and mRNA expression of MMP-10, MMP-12, and MCP-1 in the glomeruli. Both albuminuria and BUN were significantly reduced in treated mice. Mesangial filopodial invasion of the capillary tufts was blunted, and the GBM ultrastructure was normalized. There was no effect on lifespan.

Conclusion

LOXL2 plays an important role in promoting both glomerular and interstitial pathogenesis associated with Alport syndrome in mice. LOXL2i may provide beneficial effects for treating human Alport syndrome and may extend to other etiologies of CKD given strong association between renal fibrosis and outcomes in end stage renal disease.

Funding

  • Commercial Support