Dataset Information

Immunoregulatory potential of mesenchymal stem cells following activation by macrophage-derived soluble factors.

ABSTRACT:

Background

Immunoregulatory capacity of mesenchymal stem cells (MSC) is triggered by the inflammatory environment, which changes during tissue repair. Macrophages are essential in mediating the inflammatory response after injury and can adopt a range of functional phenotypes, exhibiting pro-inflammatory and anti-inflammatory activities. An accurate characterization of MSC activation by the inflammatory milieu is needed for improving the efficacy of regenerative therapies. In this work, we investigated the immunomodulatory functions of MSC primed with factors secreted from macrophages polarized toward a pro-inflammatory or an anti-inflammatory phenotype. We focused on the role of TNF-? and IL-10, prototypic pro-inflammatory and anti-inflammatory cytokines, respectively, as priming factors for MSC.

Methods

Secretion of immunoregulatory mediators from human MSC primed with media conditioned by human macrophages polarized toward a pro-inflammatory or an anti-inflammatory phenotype was determined. Immunomodulatory potential of primed MSC on polarized macrophages was studied using indirect co-cultures. Involvement of TNF-? and IL-10 in priming MSC and of PGE₂ in MSC-mediated immunomodulation was investigated employing neutralizing antibodies. Collagen hydrogels were used to study MSC and macrophages interactions in a more physiological environment.

Results

Priming MSC with media conditioned by pro-inflammatory or anti-inflammatory macrophages enhanced their immunomodulatory potential through increased PGE₂ secretion. We identified the pro-inflammatory cytokine TNF-? as a priming factor for MSC. Notably, the anti-inflammatory IL-10, mainly produced by pro-resolving macrophages, potentiated the priming effect of TNF-?. Collagen hydrogels acted as instructive microenvironments for MSC and macrophages functions and their crosstalk. Culturing macrophages on hydrogels stimulated anti-inflammatory versus pro-inflammatory cytokine secretion. Encapsulation of MSC within hydrogels increased PGE₂ secretion and potentiated immunomodulation on macrophages, attenuating macrophage pro-inflammatory state and sustaining anti-inflammatory activation. Priming with inflammatory factors conferred to MSC loaded in hydrogels greater immunomodulatory potential, promoting anti-inflammatory activity of macrophages.

Conclusions

Factors secreted by pro-inflammatory and anti-inflammatory macrophages activated the immunomodulatory potential of MSC. This was partially attributed to the priming effect of TNF-? and IL-10. Immunoregulatory functions of primed MSC were enhanced after encapsulation in hydrogels. These findings may provide insight into novel strategies to enhance MSC immunoregulatory potency.

SUBMITTER: Saldana L

PROVIDER: S-EPMC6375172 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Publications

Immunoregulatory potential of mesenchymal stem cells following activation by macrophage-derived soluble factors.

Saldaña Laura L Bensiamar Fátima F Vallés Gema G Mancebo Francisco J FJ García-Rey Eduardo E Vilaboa Nuria N

Stem cell research & therapy 20190213 1

<h4>Background</h4>Immunoregulatory capacity of mesenchymal stem cells (MSC) is triggered by the inflammatory environment, which changes during tissue repair. Macrophages are essential in mediating the inflammatory response after injury and can adopt a range of functional phenotypes, exhibiting pro-inflammatory and anti-inflammatory activities. An accurate characterization of MSC activation by the inflammatory milieu is needed for improving the efficacy of regenerative therapies. In this work, w ...[more]

PMID: 30760316

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Project description:Tissue regeneration or healing both require efficient vascularization within a tissue-damaged area. Based on this concept, a remarkable number of strategies, aimed at developing new tools to support re-vascularization of damaged tissue have emerged. Among the strategies proposed, the use of pro-angiogenic soluble factors, as a cell-free tool, appears as a promising approach, able to overcome the issues concerning the direct use of cells for regenerative medicine therapy. Here, we compared the effectiveness of adipose mesenchymal stem cells (ASCs), use as cell suspension, ASC protein extract or ASC-conditioned-medium (i.e., soluble factors), combined with collagenic scaffold, in supporting in vivo angiogenesis. We also tested the capability of hypoxia in increasing the efficiency of ASC to promote angiogenesis, via soluble factors, both in vivo and in vitro. In vivo studies were performed using the Integra® Flowable Wound Matrix, and the Ultimatrix in sponge assay. Flow cytometry was used to characterize the scaffold- and sponge-infiltrating cells. Real-time PCR was used to evaluate the expression of pro-angiogenic factors by stimulating Human Umbilical-Vein Endothelial Cells with ASC-conditioned media, obtained in hypoxic and normoxic conditions. We found that, in vivo, ACS-conditioned media can support angiogenesis similar to ASCs and ASC protein extract. Also, we observed that hypoxia increases the pro-angiogenic activities of ASC-conditioned media, compared to normoxia, by generating a secretome enriched in pro-angiogenic soluble factors, with bFGF, Adiponectine, ENA78, GRO, GRO-a, and ICAM1-3, as most regulated factors. Finally, ASC-conditioned media, produced in hypoxic condition, induce the expression of pro-angiogenic molecules in HUVECs. Our results provide evidence that ASC-conditioned-medium can be proposed as a cell-free preparation able to support angiogenesis, thus providing a relevant tool to overcome the issues and restrictions associated with the use of cells.

Project description:UnlabelledMesenchymal stem cells (MSCs) exhibit immunosuppressive efficacy and significantly inhibit the formation of the atherosclerosis (AS) plaque in apolipoprotein E-knockout (apoE(-/-)) mice. Of note, the largest lymphoid organ, the skin, provides a readily accessible and ideal source of tissue for the isolation of MSCs: skin-derived MSCs (S-MSCs). However, the effect and the mechanism of the therapeutic properties of S-MSCs in the progression of AS are unclear. We therefore investigated a direct effect of S-MSC treatment in the formation of atherosclerotic plaque in apoE(-/-) mice. Fifty apoE(-/-) mice were divided into four groups: the control group (AS), the S-MSC treatment group (S-MSC treatment), the nuclear factor-κB (NF-κB)(-/-)-S-MSC treatment group (KO-S-MSC treatment), and the additional S-MSC migration group. Brachiocephalic artery ultrasound biomicroscope (UBM) analysis showed that S-MSC treatment significantly reduced lesion size compared with the control groups (p < .01). Histological studies demonstrated that the plaque area of the mouse aortic arch was significantly decreased after S-MSC treatment. All alterations were dependent on NF-κB activation. After tail-vein injection, S-MSCs were capable of migrating to atherosclerotic plaque and selectively taking up residence near macrophages. S-MSC treatment reduced the release of the proinflammatory cytokine tumor necrosis factor (TNF)-α and increased the expression of the anti-inflammatory factor interleukin (IL)-10 in the atherosclerotic plaque, which was also dependent on NF-κB activation. In vitro, we found lipopolysaccharide (LPS) induced NF-κB-dependent expression of cyclooxygenase-2 (COX-2) in S-MSCs. Prostaglandin E2 (PGE2) expression was markedly increased after LPS-stimulated S-MSCs were cocultured with macrophages. LPS-stimulated macrophages produced less TNF-α/IL-1β and more IL-10 when cultured with S-MSCs, and although both were dependent upon NF-κB, the release of IL-10 was diminished if the S-MSCs were pretreated with a COX-2 inhibitor or an EP2/EP4 antagonist. Our data demonstrated that S-MSCs inhibited the formation of the atherosclerotic plaque in apoE(-/-) mice by modulating the functionality of macrophages, suggesting that S-MSCs may potentially have a role in stem cell-based therapy for AS.SignificanceA combination of in vitro and in vivo experiments showed that skin-derived mesenchymal stem cells (S-MSCs) can attenuate the plaque size of atherosclerosis. This is probably because S-MSCs beneficially modulate the response of macrophages through an increased release of prostaglandin E2 acting on the EP2 and EP4 receptors of the macrophages, stimulating the production and release of the anti-inflammatory cytokine interleukin-10, and decreasing the production of proinflammatory cytokine tumor necrosis factor-α. S-MSCs inhibited the formation of the atherosclerotic plaque in apolipoprotein E-knockout mice by modulating the functionality of macrophages, and the suppressive property of S-MSCs is dependent on NF-κB signaling. This study provides direct evidence that S-MSCs have a potent immunosuppressive effect in the development of atherosclerosis in mice, suggesting that S-MSCs can easily be cultured and have similar function to bone marrow-derived MSCs, a promising cell source for stem cell-based therapies of atherosclerosis, and possibly also in transplantation.

Dataset Information

Immunoregulatory potential of mesenchymal stem cells following activation by macrophage-derived soluble factors.

Background

Methods

Results

Conclusions

Publications

Immunoregulatory potential of mesenchymal stem cells following activation by macrophage-derived soluble factors.

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