Post-transcriptional suppression of TIMP-1 in epithelial-differentiated adipose-derived stem cells seeded bladder acellular matrix grafts reduces urethral scar formation.

Prevention of fibrosis and urethral scar formation is critical for a successful urethral reconstruction. We have previously shown that epithelial-differentiated adipose-derived stem cells (EASC) seeded bladder acellular matrix grafts (BAMG) can be used for urethral reconstruction. We have also shown that suppression of tissue inhibitor of metalloproteinases-1 (TIMP-1) reduces epithelial-mesenchymal transition in urethral fibroblasts in vitro and in vivo. However, it is unknown whether suppression of TIMP-1 in EASC seeded BAMG may benefit urethral reconstruction through inhibition of fibrosis. Here, we addressed this question. In a rabbit substitution urethroplasty model, we found that E-cadherin + EASC resulted in wider urethral caliber and formation of less urethral scar tissue, compared to non-purified EASC. Bioinformatics study showed that among all TIMP-1-targeting microRNAs (miRNAs), miR-365 is a conserved one in rabbits and humans, and functionally inhibits TIMP-1 protein translation. MiR-365-transduced E-cadherin + EASC seeded BAMG further reduced fibrosis and increased urethral caliber width during urethral reconstruction in rabbits, compared to E-cadherin + EASC seeded BAMG. Together, these data suggest that EASC seeded BAMG method for urethral reconstruction could be further improved through purification of EASC by E-cadherin and through post-transcriptional inhibition of TIMP-1 via miR-365 in EASC.