RESUMO
Stem cells from human exfoliated deciduous teeth (SHED) have stromal-derived inducing activity (SDIA): which means these stromal cells induce neural differentiation where they are used as a substratum for embryonic stem cell (ESCs) culture. Recent studies show that mitochondria or mitochondrial products, as paracrine factors, can be released and transferred from one cell to another. With this information, we were curious to know whether in the SDIA co-culture system, SHED release or donate their mitochondria to ESCs. For this purpose, before co-culture, SHED s' mitochondria and ESCs s' cell membranes were separately labeled with specific fluorescent probes. After co-culture, SHED s' mitochondria were tracked by fluorescent microscope and flow cytometry analysis. Co-culture also performed in the presence of inhibitors that block probable transfer pathways suchlike tunneling nanotubes, gap junctions or vesicles. Results showed that mitochondrial transfer takes place from SHED to ESCs. This transfer partly occurs by tunneling nanotubes and not through gap junctions or vesicles; also was not dependent on intracellular calcium level. This kind of horizontal gene transfer may open a new prospect for further research on probable role of mitochondria on fate choice and neural induction processes.
