FN1 and renal fibrosis: In contrast to the findings with Insig1ΔKap mice, fibroblast deficiency of Insig1 did not worsen UUO-induced renal fibrosis, as evidenced by unchanged collagen deposition and fibrotic indicator (Fn, Acta2, Col3a1, and Vim) mRNA expressions in the kidneys (Fig. 4D,E).