Figure 2.

Mitochondrial transfer from WJMSCs to MELAS fibroblasts pretreated with rotenone. (a) Schematic of a separate coculture in which a 3 μm pore membrane divides Cox4-DsRed-expressing WJMSCs from MELAS fibroblast. (b) Experimental course shows that MELAS fibroblasts pretreated with 500 nM rotenone for 24 h, followed by a 7-day coculture. Mitochondrial transfer and mtDNA mutation burden were examined at the indicated time point. (c) Representative image of mitochondrial transfer from WJMSCs to MELAS fibroblast. Arrowheads indicate mitochondrial transfer of WJMSCs into MELAS fibroblast. (d) Quantitative results of mitochondrial transfer efficiency. (e) Schematic of the blended coculture. WJMSCs from MELAS fibroblast, respectively, labeled with mitochondrial Cox-DsRed and Su9-EGFP were subjected to blend coculture for one day. (f) Representative image of intercellular mitochondrial transfer. Arrowheads indicate mitochondrial transfer of WJMSCs. Arrows indicate hybrid mitochondria. ^∗ p < 0.05 significantly different when compared to any other group. WJ: Wharton's jelly mesenchymal stem cell; MF^Neg: MELAS fibroblast clone harboring negative mutation burden; MF^Hi: MELAS fibroblast clone harboring high mutation burden; WJ^CB: WJMSCs pretreated with 350 nM cytochalasin B for 24 h before coculture.