CXCL5 inhibition ameliorates acute kidney injury and prevents the progression from acute kidney injury to chronic kidney disease

Acute kidney injury (AKI) increases the risk of chronic kidney disease (CKD). CXC motif chemokine ligand 5 (CXCL5) is up-regulated in kidney diseases. We aimed to investigate the direct effect of CXCL5 on the pathology of AKI. Serum and renal expression of CXCL5 were increased in animals with renal ischemia-reperfusion injury or unilateral ureteral obstruction. CXCL5-knockout mice exhibited reduced systemic oxidative stress and preserved renal function in the acute and chronic phases of AKI, as evidenced by reductions in serum BUN and creatinine levels, the urinary albumin-to-creatinine ratio, and the kidney-to-body weight ratio. CXCL5-knockout mice improved AKI-induced tubular injury and fibrosis, reduced renal macrophage infiltration, and reduced expression of NADPH oxidase and inflammatory and fibrotic proteins. CXCL5 activated p47 to up-regulate ROS generation and induce cellular damages through CXCR2. CXCL5 knockdown exerted antioxidative, anti-inflammatory, anti-fibrotic, and anti-apoptotic effects on hypoxia-reoxygenation-stimulated renal proximal tubular epithelial cells. Clinical data indicated elevated circulating and renal CXCL5 in CKD patients, and renal CXCL5 was correlated with increased renal fibrosis and decreased estimated glomerular filtration rate. Altogether, CXCL5 levels increased in experimental AKI and clinical CKD, and in vivo and in vitro CXCL5 inhibition may reduce acute tubular injury and prevent the subsequent progression from AKI to CKD.