Fig. 4.

miR-29 inhibition induces fibrosis in vivo. (A) Northern blot analysis showing knockdown of miR-29b expression three days after i.v. injection of 80 mg/kg of either anti-miR-29 or mm miR-29 or a comparable volume of saline. (B) Real-time PCR analysis of liver extracts reveals a pronounced increase in collagen expression in response to miR-29 knockdown, whereas this effect was absent after saline or mm injection. (C) Northern blot of the indicated tissues 3 weeks after i.v. injection with 80 mg/kg on two consecutive days of either anti-miR-29 or mm miR-29 oligonucleotide or a comparable volume of saline. miR-29 is nearly abolished in the liver, heart and kidney, whereas miR-29 levels in lung appear unaffected by anti-miR-29. (D) Real-time PCR analysis of heart extracts indicates an increase in cardiac collagen expression in response to miR-29 knockdown. (n = 2 per group, *, P < 0.05 compared with mm treated animals). (E) Cardiac fibroblasts were either left untreated or treated with 1 or 5 nM miR-29b mimic for 48 h. Real-time PCR analysis indicates an increase in miR-29b expression in fibroblasts two days after miR-29b mimic treatment, whereas miR-29a levels were unchanged and miR-29c levels only slightly increased. (F) Cardiac fibroblasts that were either left untreated or treated with 1 or 5 nM miR-29b mimic for 48 h show a decrease in expression of collagen genes in response to increased levels of miR-29b as determined by real-time PCR analysis.