Kidney
fibrosis is a histological hallmark of
chronic kidney disease (CKD) and is believed to be involved in the progression of CKD. Therefore, inhibition of kidney
fibrosis is a potential strategy for slowing CKD progression.
Signal transducer and activator of transcription 3 (STAT3) is a
transcription factor that is activated by
interleukin-6 and is reported to be involved in
fibrosis. Previously,
S3I-201, an inhibitor of STAT3 phosphorylation, was shown to inhibit renal
fibrosis in a mouse model, but its mechanism was not clarified completely. In this study, we investigated whether
STX-0119, a new inhibitor of STAT3 dimerization, suppressed kidney fibrotic gene expression using a mouse model of kidney
fibrosis and examined the underlying mechanisms. Kidney
fibrosis was induced by unilateral
ureteral obstruction (UUO), which was accompanied by upregulation of STAT3 target genes.
STX-0119 administration suppressed the expression of fibrotic genes in UUO kidneys without affecting STAT3 phosphorylation.
STX-0119 decreased Cxcr4
mRNA in cultured rat kidney fibroblasts and Ccr1
mRNA in blood cells from UUO mice, both of which are reported to be involved in the progression of kidney
fibrosis. These results suggest that
STX-0119 inhibits fibrotic gene expression in kidney by suppressing Cxcr4 and Ccr1 expression. This is the first report to indicate a part of the mechanism of the antifibrotic effects of a STAT3 inhibitor and suggests that
STX-0119 may be a lead compound for the treatment of kidney
fibrosis.