Genome Edited Sirt1-Overexpressing Human Mesenchymal Stem Cells Exhibit Therapeutic Effects in Treating Collagen-Induced Arthritis.

Even though mesenchymal stem cells (MSCs) are known for cartilage regeneration, their therapeutic efficacy needs to be enhanced. In the present study, we produced genome-edited silent information regulator 2 type 1 (Sirt1)-overexpressing MSCs, and evaluated their therapeutic potential in a damaged cartilage mouse liver fibrosis model. The Sirt1 gene was successfully inserted into a 'safe harbor' genomic locus in amniotic mesenchymal stem cells (AMMs), and the chondrogenic properties of the Sirt1 gene overexpressing AMMs (AMM/S) were characterized using quantitative PCR and histology. Therapeutic potentials were investigated in a collagen-induced arthritis (CIA) mouse model. Chondrocyte-differentiated AMM/S expressed cartilage-specific genes and were positive for Safranin O staining. Transplantation of AMM/S attenuated CIA progression and suppressed T helper (Th)-17 cell activation while increasing the Treg cell population in CIA mice. Pro-inflammatory factors, such as interleukin (IL)-1β, IL-6, monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor (TNF)-α were significantly decreased in AMM/S-injected joint tissues. In conclusion, genome-edited AMM/S may represent a safe and alternative therapeutic option for the treatment and repair of damaged cartilage, or in inflammatory joint arthritis.