WNT9A and chronic kidney disease: These Wnt9a levels were positively correlated with an increase in p16INK4A and γΗ2ΑX (a selective marker of DNA double-strand break) and a decrease in the anti-aging protein Klotho (a marker of renal tubular injury and CKD).264 Increased Wnt9a ligand expression activates Wnt/β-catenin signaling, which promotes the expression of downstream profibrogenic and transcriptional targets that exacerbate renal fibrosis.264–268