SUN-169 A COPPER CHELATING DRUG INHIBITS RENAL FIBROSIS BY INHIBITING LYSYL OXIDASE AND LOSS OF PERITUBULAR CAPILLARIES

Abstract

Chronic kidney disease (CKD) is one of the important global health burdens which involves interstitial fibrosis as an underlying pathological process associated with compromised renal function irrespective of etiological cause of the injury. Lysyl oxidase (LOX) is a copper-dependent enzyme that mediates cross linking of extracellular matrix (ECM) proteins including collagen and elastin. The proper LOX activity is essential for a physiologically functional ECM, while the aberrant expression of LOX and related proteins has been found in conditions with excessively deposited ECM such as organ fibrosis. We hypothesized that a copper chelator, disulfiram (DSF) which is used for alcohol deaddiction, could be repurposed to reduce the activation of LOX proteins and subsequent reduction in collagen deposition in fibrotic conditions. We used Male Swiss albino mice for unilateral ureteral obstruction (UUO)-induced animal model of renal fibrosis and investigated the effects of DSF (10 and 30 mg/kg) on LOX and LOX-like (LOXL) proteins as a strategy to treat/prevent renal fibrosis. We used a pan-LOX inhibitor, β-aminopropionitrile (BAPN, 100 mg/kg) as a standard LOX inhibitor for comparison. We performed histopathology, hydroxyproline assay, western blot, ELISA and immunofluorescence studies to assess the effect of DSF on renal injury and fibrosis. The levels of different isoforms of LOX were found to be higher in the fibrotic kidney as compared to sham/contralateral kidney control. The treatment of animals with DSF led to reduced expression of LOX and related proteins. Interestingly, the reduction in expression of LOX proteins with DSF was found to be better than BAPN. Further, the DSF reduced UUO-induced expression of fibrotic proteins (collagen I, fibronectin, TGF-β). Furthermore, DSF reduced the phenotypic conversion of epithelial cells to mesenchymal type by reducing the epithelial-mesenchymal transition (EMT) program as evident by reduced expression of mesenchymal markers such as α-SMA and vimentin along with improved expression of epithelial marker, E-cadherin. DSF prevented renal injury, reduced tubulointerstitial fibrosis and collagen deposition in fibrotic kidney. In addition to that, DSF also prevented peritubular capillary (PTC) loss in the obstructed kidneys of animals which is a hallmark of clinical and preclinical conditions of renal fibrosis. DSF, an FDA approved drug, can be repurposed for fibrotic disorders due to its modulating effects on the expression of LOX and LOXL proteins. The DSF holds a great potential to prevent organ fibrosis and it could be used as a successful strategy for amelioration of different fibrotic conditions, if translated further.