Histone H3K9 Methylation Features under Hypoxic Conditions after the HIF1A Knockdown in Mesenchymal Stromal Cells In Vitro.

The effects of HIF1A knockdown by RNA interference on the histone H3K9 methylation in human umbilical cord mesenchymal stromal cells in vitro under conditions of 24-h exposure to hypoxia (1% O) were studied. Evaluation of transcriptional activity of genes involved in the regulation of H3K9 methylation (KDM3A, KDM4A, and EHMT2) and the cytofluorimetric analysis of the expression of the corresponding antigens and H3K9 methylation level demonstrated a pronounced stimulating effect of hypoxic exposure. Moreover, the expression of KDM4A and EHMT2 was regulated by HIF1A-mediated mechanism, unlike KDM3A; the level of the corresponding proteins depended on HIF1A.

Alteration of PBMC transcriptome profile after interaction with multipotent mesenchymal stromal cells under "physiological" hypoxia.

Multipotent mesenchymal stromal cells (MSCs) have demonstrated a pronounced immunosuppressive activity, the manifestation of which depends on the microenvironmental factors, including O level. Here we examined the effects of MSCs on transcriptomic profile of allogeneic phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMCs) after interaction at ambient (20%) or "physiological" hypoxia (5%) O. As revealed with microarray analysis, PBMC transcriptome at 20% O was more affected, which was manifested as differential expression of more than 300 genes, whereas under 5% O 220 genes were changed.

Oxygen Level Modifies the Expression of Genes Involved in the Epigenetic Regulation of Multipotent Stromal Cells In Vitro.

Changes in the transcriptional activity of genes involved in the epigenetic regulation of adipose tissue multipotent mesenchymal stromal cells were analyzed in vitro at different O levels. DNA microarray study showed that the most pronounced changes in gene expression, including genes responsible for the epigenetic regulation of mesenchymal stromal cells, occurred at 3% O. A lower number of genes changed the expression at 1% O, and a minimum response was observed at 5% O in comparison with standard culturing conditions (20% O).

Osteogenic Commitment of MSC Is Enhanced after Interaction with Umbilical Cord Blood Mononuclear Cells In Vitro.

The effectiveness of stroma-dependent expansion of hematopoietic cells ex vivo may depend on the level of commitment of multipotent mesenchymal stromal cells (MSC). Markers of MSC osteodifferentiation and the level of soluble hematopoiesis regulators were determined during their interaction with umbilical cord blood mononuclears. After 72-h co-culturing, an increase in the expression of ALPL and alkaline phosphatase activity was revealed.

Сord blood hematopoietic stem cells ex vivo enhance the bipotential commitment of adipose mesenchymal stromal progenitors.

Aims: Stroma-dependent ex vivo expansion of hematopoietic stem progenitor cells (HSPCs) is a valid approach for cell therapy needs. Our goal was to verify whether HSPCs can affect stromal cells to optimize their functions during ex vivo expansion.

Main Methods: HSPCs from cord blood (cb) were cocultured with growth-arrested adipose mesenchymal stromal cells (MSCs).

Adipose-derived stromal cell immunosuppression of T cells is enhanced under "physiological" hypoxia.

Multipotent mesenchymal stromal cells (MSCs) are characterized by immunomodulatory properties along with the high proliferative and paracrine activity, as well as multilineage potency. The effects of MSCs on the T cell adaptive immunity are of a special interest. Low O level (1-7 %) is known to be typical for the putative site of the MSC - T cell interactions.

Adipose tissue-derived stromal cells retain immunosuppressive and angiogenic activity after coculture with cord blood hematopoietic precursors.

Adipose-tissue derived stromal cells (ASCs) are currently considered as a full value alternative source of bone marrow MSCs for prevention of graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation due to their immunosuppressive potential. Besides, ASCs are known to support ex vivo expansion of hematopoietic stem and progenitor cells (HSPCs). Ex vivo expansion enables to amplify significantly the number of HSPCs of different commitment.

Phenotype and Secretome of Monocyte-Derived Macrophages Interacting with Mesenchymal Stromal Cells under Conditions of Hypoxic Stress.

We studied the effect of short-term hypoxic stress on the phenotypic polarization of monocyte-derived macrophages and their secretory activity during interaction with mesenchymal stromal cells. In the presence of mesenchymal stromal cells, monocyte-derived macrophages exhibited the signs of M2 polarization, which was evidenced by increased expression of CD206 and CD163 markers, as well as increased transcription and translation of IL-6. Short-term hypoxic stress promoted a shift of macrophage phenotype from inflammatory M1 towards anti-inflammatory M2 in monoculture and co-culture with mesenchymal stromal cells.

Reciprocal modulation of cell functions upon direct interaction of adipose mesenchymal stromal and activated immune cells.

The interaction of adipose mesenchymal stromal cells (ASCs) and allogeneic peripheral blood mononuclear cells (PBMCs) is regulated either through direct or paracrine mechanisms. Here, we examined the impact of direct contact in reciprocal regulation of ASC-PBMC functions. Activated PBMCs in vitro induced ASC immunomodulatory activity, while direct and paracrine intercellular interactions regulated PBMCs themselves: the functional state of the organelles was altered, and activation decreased.

Interaction of allogeneic adipose tissue-derived stromal cells and unstimulated immune cells in vitro: the impact of cell-to-cell contact and hypoxia in the local milieu.

Multipotent mesenchymal stem cells (MSCs) are an attractive tool for cell therapy and regenerative medicine. Being applied in vivo, allogeneic MSCs are faced with both activated and unstimulated immune cells. The effects of MSCs on activated immune cells are well described and are mainly suppressive.

Interaction of multipotent mesenchymal stromal and immune cells: Bidirectional effects.

Adult multipotent mesenchymal stromal cells (MSCs) are considered one of the key players in physiological remodeling and tissue reparation. Elucidation of MSC functions is one of the most intriguing issues in modern cell physiology. In the present review, the interaction of MSCs and immune cells is discussed in terms of reciprocal effects, which modifies the properties of "partner" cells with special focus on the contribution of direct cell-to-cell contacts, soluble mediators and local microenvironmental factors, the most important of which is oxygen tension.

Tissue-Related Hypoxia Attenuates Proinflammatory Effects of Allogeneic PBMCs on Adipose-Derived Stromal Cells In Vitro.

Human adipose tissue-stromal derived cells (ASCs) are considered a perspective tool for regenerative medicine. Depending on the application mode ASC/allogeneic immune cell interaction can occur in the systemic circulation under plenty high concentrations of O2 and in target tissues at lower O2 levels. Here we examined the effects of allogeneic PHA-stimulated peripheral blood mononuclear cells (PBMCs) on ASCs under ambient (20%) oxygen and "physiological" hypoxia (5% O2).

Proinflammatory interleukins' production by adipose tissue-derived mesenchymal stromal cells: the impact of cell culture conditions and cell-to-cell interaction.

The impact of culture conditions and interaction with activated peripheral blood mononuclear cells on the interleukin (IL) gene expression profile and proinflammatory IL-6 and IL-8 production by adipose-derived stromal cells (ASCs) was investigated. A microarray analysis revealed a wide range of IL genes either under standard (20%) or hypoxic (5%) O2 concentrations, some highly up-regulated at hypoxia. IL-6 and IL-8 production was inversely dependent on cell culture density.

Human adipose-tissue derived stromal cells in combination with hypoxia effectively support ex vivo expansion of cord blood haematopoietic progenitors.

The optimisation of haematopoietic stem and progenitor cell expansion is on demand in modern cell therapy. In this work, haematopoietic stem/progenitor cells (HSPCs) have been selected from unmanipulated cord blood mononuclear cells (cbMNCs) due to adhesion to human adipose-tissue derived stromal cells (ASCs) under standard (20%) and tissue-related (5%) oxygen. ASCs efficiently maintained viability and supported further HSPC expansion at 20% and 5% O2.

[PROFILE OF THE MARROW-DERIVED STROMAL PRECURSORS POPULATION IN C57BL/6N MICE FLOWN ON BIOSATELLITE BION-M1].

The CFU-F number, proliferative activity and spontaneous differentiation potential of stromal cells derived from the tibia marrow of C57BL/6N mice readapted to the 1-g gravity following a long-term flight on biosatellite Bion-M1 were evaluated. The CFU-F number, proliferative activity and spontaneous adipogenic and osteogenic differentiation of marrow-derived stromal cells from the space flown group were no different from the group of vivarium control. However, the proliferative activity and adhesion properties of the cells were down-regulated on day 7 of readaptation.

Enrichment of umbilical cord blood mononuclears with hemopoietic precursors in co-culture with mesenchymal stromal cells from human adipose tissue.

We demonstrated the possibility of enrichment of umbilical cord blood mononuclear fraction with early non-differentiated precursors under conditions of co-culturing with mesenchymal stromal cells from the human adipose tissue. It was established that umbilical cord blood mononuclear cells adhered to mesenchymal stromal cell feeder and then proliferate and differentiate into hemopoietic cells. In comparison with the initial umbilical cord blood mononuclear fraction, the cell population obtained after 7-day expansion contained 2-fold more CFU and 33.

[Human lymphocyte immunophenotype after interaction with mesenchymal stromal cells].

Human multipotent mesenchymalstromal cells were cocultured for 72h with allogeneic blood-borne mononuclear cells (MNCs) of different maturity (lymphocytes from adult peripheral blood and umbilical cord blood) and functional state (intact and PHA-activated human peripheral blood lymphocytes): After coculture with MMSCs the share ofB-cells among MNCs and cbMNCs decreased. The proportion ofT- and NK cells declined only among cbMNCs (p < 0.05).