Transcription factor Tbx18 induces the differentiation of c-kit+ canine mesenchymal stem cells (cMSCs) into SAN-like pacemaker cells in a co-culture model in vitro.

We examined whether the overexpression of Tbx18 can induce the differentiation of c-kit+ cMSCs into a phenotype similar to that of native pacemaker cells and whether these transfected cells can couple to adjacent atrial cells with functional consequences. The c-kit+ cMSCs were first sorted, then transfected with different lentiviral vectors. Tbx18-c-kit+ cMSCs represented the experimental group, while EYFP-c-kit+ cMSCs and canine sinoatrial node (SAN) cells were used as controls. Within days of transfection, the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel HCN4 protein and gap junction protein Connexin 45 (Cx45) expression in Tbx18-c-kit+ cMSCs were 12-fold and 5.6-fold higher, respectively, than that in EYFP-c-kit+ cMSCs. After co-culture with canine atrial cells in vitro for three days, the funny currents (If) were recorded in the Tbx18-c-kit+ cMSCs, but not in EYFP-c-kit+ cMSCs. The trend of these If currents was highly similar to that of SAN cells, although the current density was smaller. The Tbx18-EYFP-c-kit+ cMSCs showed responsiveness to β-adrenergic stimulation, and the intracellular cyclic adenosine monophosphate (cAMP) level was higher than that in EYFP-c-kit+ cMSCs. The Tbx18-EYFP-c-kit+ cMSCs delivered fluorescent dye to neighboring atrial cells via gap junctions, thus these cell pairs could communicate as a pacemaker unit. We propose that the overexpression of Tbx18 in c-kit+ cMSCs induces their differentiation to SAN-like pacemaker cells. ...
Source: American Journal of Translational Research - Category: Research Tags: Am J Transl Res Source Type: research