Modulation of AKT/GSK-3β signaling by ambrisentan alleviates chronic kidney disease

Chronic kidney disease (CKD) is a progressive disease leading to severe health complications. Repurposing of existing drugs offers an attractive avenue for advancing drug development in CKD. Ambrisentan (AMB), a selective ET-1_A receptor antagonist used in pulmonary arterial hypertension, holds promise in CKD management. Hence, we aimed to investigate the potential of AMB in unilateral ureteral obstruction (UUO)-induced kidney fibrosis in Sprague-Dawley rats and in recombinant human-transforming growth factor-β1 (rh-TGF-β1)-induced fibrosis in NRK-52E cells. Animals were randomly assigned to the sham, UUO, and UUO + AMB (0.5 mg/kg, p.o., o.d.) groups for 21 days. Animals were sacrificed post-treatment, and plasma, urine, and kidney specimens were collected for biochemistry, histology, immunohistochemistry and qRT-PCR. Moreover, NRK-52E cells were exposed to AMB (100 µM) for 48 h and cell samples were collected for cell viability, morphology, immunocytochemistry, immunoblotting, and flow cytometry assays. AMB treatment significantly improves the left kidney weight, kidney mass ratio, kidney function parameters, and plasma protein levels of TGF-β1 and collagen I. Histopathology revealed that AMB treatment significantly preserved kidney histoarchitecture and interstitial fibrosis in UUO kidneys. Mechanistically, AMB suppressed phosphorylation of AKT and GSK-3β, downregulated α-SMA, vimentin and restored E-cadherin expression as shown by immunocytochemistry, immunohistochemistry and immunoblotting assay. Furthermore, AMB mitigated rh-TGF-β1-induced apoptosis, as assessed by flow cytometry, and modulated Bax, Bcl-2, and cleaved caspase-3 expression, as revealed by qRT-PCR and immunohistochemistry. Collectively, the findings indicate that the AMB modulates the AKT/GSK-3β axis, halting fibrotic progression in CKD, suggesting its clinical potential.