Interstitial
fibrosis is a common feature of
chronic kidney disease, and
platelet-derived growth factor receptor-β (PDGFR-β)-positive mesenchymal cells are reportedly the major source of
scar-producing myofibroblasts. We had previously demonstrated that
albumin and its derivative R-III (a
retinol-binding protein-
albumin domain III fusion
protein) inhibited the transdifferentiation/activation of hepatic stellate cells (HSCs) to myofibroblasts and that R-III administration reduced
liver fibrosis. In this study, we isolated cells (referred to as renal stellate cells, RSCs) from rat kidney tissues using the HSC isolation protocol and compared their morphological and biochemical characteristics with those of HSCs. RSCs shared many characteristics with HSCs, such as storage of
vitamin A-containing lipid droplets and expression of HSC markers as well as pericyte markers. RSCs underwent spontaneous transdifferentiation into myofibroblasts in in vitro culture, which was inhibited by
albumin expression or R-III treatment. We also evaluated the
therapeutic effects of R-III in unilateral
ureteral obstruction (UUO)-induced renal
fibrosis in mice. Injected R-III localized predominantly in
cytoglobin/stellate cell activation-associated
protein (Cygb/STAP)-positive cells in the kidney and reduced renal
fibrosis. These findings suggest that RSCs can be recognized as the renal counterparts of HSCs and that RSCs represent an attractive therapeutic target for anti-fibrotic
therapy.