EPRS1-mediated fibroblast activation and mitochondrial dysfunction promote kidney fibrosis

Abstract

Kidney fibrosis is characterized by an aberrant extracellular matrix accumulation. Glutamyl-prolyl-tRNA synthetase 1 (EPRS1) is a crucial enzyme involved in the synthesis of proline-rich proteins. However, its role in kidney fibrosis remains unclear. The present study found that EPRS1 expression levels were increased in the fibrotic kidneys of patients and mice. We also found that fibroblasts and proximal tubular epithelial cells were major sources of EPRS1 based on single-cell analysis and immunostaining of fibrotic kidneys. C57BL/6 EPRS1^tm1b heterozygous knockout (Eprs1^+/−) attenuated kidney fibrosis and dysfunction by preventing fibroblast activation and proximal tubular injury. In vitro assays demonstrated that EPRS1-induced Smad3 phosphorylation promotes fibroblast activation, proliferation, and resultant collagen production under transforming growth factor-β treated conditions. We also found that EPRS1 could lead to STAT3 phosphorylation to induce mitochondrial dysfunction in injured proximal tubules. Moreover, first-in-class EPRS1 inhibitor DWN12088 effectively protected against kidney fibrosis and dysfunction. Our findings suggest that EPRS1-mediated extracellular matrix induces kidney fibrosis via fibroblast activation and mitochondrial dysfunction.