Phenotypic Features of Mesenchymal Stem Cell Subpopulations Obtained under the Influence of Various Toll-Like Receptors Ligands.

The paper characterizes phenotypic features of subpopulations of human adipose tissue mesenchymal stem cells (MSC) resulting from exposure to Toll-like receptors ligands. MSC1 and MSC2 phenotypes were induced by exposure to LPS and polyinosinic-polycytidylic acid, respectively. Different exposures to Toll-like receptors ligands, short-term (3 h) and long-term (24 h), were studied. The cytokine profile of cells with the MSC2 phenotype differed depending on the duration of exposure to the inductor, while the cytokine profile of cells with the MSC1 phenotype remained stable. Morphometric features of mesenchymal stem cells with the MSC1 and MSC2 phenotypes, as well as differences in the IDO gene expression were identified. These differences can be used to distinguish between these cell types.

Activation of TLR4 of Mesenchymal Stem Cells Enhances the Regenerative Properties of Their Secretomes.

Mesenchymal stem cells (MSC), like macrophages, can be polarized in vitro. In particular, activation of type 4 Toll-like receptor in MSC leads to the appearance of the so-called "proinflammatory" MSC phenotype (MSC1). We showed that secretome (conditioned media) of MSC1 can affect the wound healing processes: promote healing and modulate exudative inflammation and subsequent fibroplastic processes in the damaged area. These effects of secretomes of polarized MSC were superior to those of intact MSC.