A role for heme oxygenase-1 in the immunosuppressive effect of adult rat and human mesenchymal stem cells

Abstract

Mesenchymal stem cells (MSCs) display immunomodulatory properties mediated by various factors, including inducible nitric oxide synthase (iNOS). Since heme oxygenase-1 (HO-1) is a potent immunosuppressive enzyme, we tested the hypothesis that HO-1 could mediate the immunosuppressive effects of MSCs. We generated adult rat MSCs that inhibited T-cell proliferation in vitro. These MSCs expressed both HO-1 and iNOS. In vitro, whereas neither HO-1 nor iNOS inhibition alone could interfere with the immunosuppressive properties of rat MSCs, simultaneous inhibition of both enzymes restored T-cell proliferation. In vivo, injection of MSCs significantly delayed heart allograft rejection, and inhibition of either HO-1 or iNOS totally reversed the protective activity of MSCs, inducing rejection. Adult human MSCs also expressed HO-1; in these cells, HO-1 inhibition was sufficient to completely block their immunosuppressive capacity. In con IntroductionThe possibility that mesenchymal stem cells (MSCs) could modulate the immune response in vivo 1 was first suggested by skin graft experiments in nonhuman primates. Strong nonspecific immunosuppressive properties have been reported in vitro for both humans and rodent MSCs. [2][3][4] Various mechanisms have been proposed to explain such properties, including production of transforming growth factor beta (TGF␤), 5 hepatocyte growth factor, PGE2, 6 IL-10, 5 and indoleamine 2,3-dioxygenase (IDO), 7,8 as well as suppression of antigen-presenting cell (APC) maturation. 9,10 A recent study demonstrated that the suppressive activity of murine MSCs is dependent on inducible NO synthase (iNOS) expression. 11 However, the precise mechanism of action of these cells remains poorly understood. It is interesting to note, however, that MSCs are not intrinsically immunoprivileged, since allogeneic MSCs can induce a memory T-cell response. 12 Heme oxygenases (HOs) are the rate-limiting intracellular enzymes that degrade heme to biliverdin, CO, and free divalent iron 13 . The inducible form, HO-1, has been described as an anti-inflammatory 13 and immunosuppressive molecule. 14 Furthermore, HO-1 can mediate the effect of molecules such as IL-10 and NO. 15 We thus hypothesized that HO-1 could contribute to the immunosuppressive properties of adult rat and human MSCs. Materials and methodsThis study was approved by the Institutional Review Board of Nantes University. MSC cultureAdult rat MSCs were obtained from LEW.1A and LEW.1W (complete major histocompatibility complex [MHC] I and II mismatch) bone marrow cells collected by flushing femurs and tibias with alpha MEM medium supplemented with 20% fetal calf serum, penicillin, and streptomycin. Adult rat MSCs were regularly split using trypsin and used before passage 4. Culture of human MSCs was performed in the same conditions from bone marrow aspirates from healthy volunteer donors who had provided informed consent in accordance with the Declaration of Helsinki. Adherent cells displayed a morphology and phenotype AbCys, Paris, France typical of ...

IFN‐γ activation of mesenchymal stem cells for treatment and prevention of graft versus host disease

“…Comparison of TNF-a and IFN-c treatment of MSC revealed that IFN-c treatment induced IDO as well as COX-2 and PGE 2 production [49]. Heme-oxygenase 1 is also observed in the pro-inflammatory milieu, and can be elicited by MSC in conditions of hypoxia, also leading to T cell suppression [50]. TGF-b, also secreted by MSC, could also be instrumental in suppression [51].…”

How stem cells speak with host immune cells in inflammatory brain diseases

“…Data in Table 1 are in part summarized in (Chamberlain et al, 2008;Hall et al, 2006;Martino and Pluchino 2006;Pluchino et al, 2009b;Rojewski et al, 2008;Uccelli et al, 2008;Yuan et al, 2011). (Cusimano et al, 2012;Jaderstad et al, 2010) aracrine IDO-kynurenine MSCs (h) T cells, DCs T cell apoptosis, inhibition of antigen presentation (Lanz et al, 2010;Matysiak et al, 2008Matysiak et al, , 2011Meisel et al, 2004;Plumas et al, 2005 Bonnamain et al, 2012;Chabannes et al, 2007;Moll et al, 2011) Paracrine VEGF NPCs Microglia/macrophages Inhibition of microglial activation, proliferation and phagocytosis (Horie et al, 2011;Kim et al, 2009a;Mosher et al, 2012) Paracrine LIF NPCs Th17 cells Inhibition of Th17 cell differentiation (Cao et al, 2011;Horie et al, 2011;Kim et al, 2009a;Mosher et al, 2012) Paracrine Galectins MSCs/NPCs T cells Inhibition of T cell proliferation (Gieseke et al, 2010;Sioud 2011;Yamane et al, 2010Yamane et al, , 2011 Endocrine/Paracrine TSG-6 MSCs Macrophages Inhibition of macrophage activation, proliferation and phagocytosis (Fisher-Shoval et al, 2012;Lee et al, 2009;Roddy et al, 2011) EVs miR transfer MSCs/NPCs Multiple Post-transcriptional regulation (Bruno et al, 2009;Chen et al, 2010;…”

Multipotent stromal cells skew monocytes towards an anti-inflammatory interleukin-10-producing phenotype by production of interleukin-6

“…7,8 Soluble factors proposed to be involved in this effect include indoleamine 2,3-dioxygenase, prostaglandin E2, transforming growth factor-β1, interleukin (IL)-6 and heme oxygenase 1. [9][10][11][12][13] MSC also inhibit the proliferation of B cells and IL-2-stimulated natural killer cells 14,15 and have been described to promote the formation of regulatory T cells (Treg). [16][17][18] MSC can also modulate immune responses through inhibition of monocyte-derived immature dendritic cell (iDC) differentiation.…”