Immunosuppressive potential of human amnion epithelial cells in the treatment of experimental autoimmune encephalomyelitis

BACKGROUND: Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS). In recent years, it has been found that cells such as human amnion epithelial cells (hAECs) have the ability to modulate immune responses in vitro and in vivo and can differentiate into multiple cell lineages. Accordingly, we investigated the immunoregulatory effects of hAECs as a potential therapy in an MS-like disease, EAE (experimental autoimmune encephalomyelitis), in mice. METHODS: Using flow cytometry, the phenotypic profile of hAECs from different donors was assessed. The immunomodulatory properties of hAECs were examined in vitro using antigen-specific and one-way mixed lymphocyte proliferation assays. The therapeutic efficacy of hAECs was examined using a relapsing-remitting model of EAE in NOD/Lt mice. T cell responsiveness, cytokine secretion, T regulatory, and T helper cell phenotype were determined in the peripheral lymphoid organs and CNS of these animals. RESULTS: In vitro, hAECs suppressed both specific and non-specific T cell proliferation, decreased pro-inflammatory cytokine production, and inhibited the activation of stimulated T cells. Furthermore, T cells retained their naïve phenotype when co-cultured with hAECs. In vivo studies revealed that hAECs not only suppressed the development of EAE but also prevented disease relapse in these mice. T cell responses and production of the pro-inflammatory cytokine interleukin (IL)-17A were reduced in hAEC-treated mice, and this was coupled with a significant increase in the number of peripheral T regulatory cells and naïve CD4+ T cells. Furthermore, increased proportions of Th2 cells in the peripheral lymphoid organs and within the CNS were observed. CONCLUSION: The therapeutic effect of hAECs is in part mediated by inducing an anti-inflammatory response within the CNS, demonstrating that hAECs hold promise for the treatment of autoimmune diseases like MS

Comparative Study on the Therapeutic Potential of Neurally Differentiated Stem Cells in a Mouse Model of Multiple Sclerosis

Background: Transplantation of neural stem cells (NSCs) is a promising novel approach to the treatment of neuroinflammatory diseases such as multiple sclerosis (MS). NSCs can be derived from primary central nervous system (CNS) tissue or obtained by neural differentiation of embryonic stem (ES) cells, the latter having the advantage of readily providing an unlimited number of cells for therapeutic purposes. Using a mouse model of MS, we evaluated the therapeutic potential of NSCs derived from ES cells by two different neural differentiation protocols that utilized adherent culture conditions and compared their effect to primary NSCs derived from the subventricular zone (SVZ). Methodology/Principal Findings: The proliferation and secretion of pro-inflammatory cytokines by antigen-stimulated splenocytes was reduced in the presence of SVZ-NSCs, while ES cell-derived NSCs exerted differential immunosuppressive effects. Surprisingly, intravenously injected NSCs displayed no significant therapeutic impact on clinical and pathological disease outcomes in mice with experimental autoimmune encephalomyelitis (EAE) induced by recombinant myelin oligodendrocyte glycoprotein, independent of the cell source. Studies tracking the biodistribution of transplanted ES cellderived NSCs revealed that these cells were unable to traffic to the CNS or peripheral lymphoid tissues, consistent with the lack of cell surface homing molecules. Attenuation of peripheral immune responses could only be achieved through multiple high doses of NSCs administered intraperitoneally, which led to some neuroprotective effects within the CNS

Hematopoietic stem cell transplantation for multiple sclerosis:Is it a clinical reality?

Hematopoietic stem cell transplantation (HSCT) is a treatment paradigm that has long been utilized for cancers of the blood and bone marrow but has gained some traction as a treatment paradigm for multiple sclerosis (MS). Success in the treatment of patients with this approach has been reported primarily when strict inclusion criteria are imposed that have eventuated a more precise understanding of MS pathophysiology, thereby governing trial design. Moreover, enhancing the yield and purity of hematopoietic stem cells during isolation along with the utility of appropriate conditioning agents has provided a clearer foundation for clinical translation studies. To support this approach, preclinical data derived from animal models of MS, experimental autoimmune encephalomyelitis, have provided clear identification of multipotent stem cells that can reconstitute the immune system to override the autoimmune attack of the central nervous system. In this review, we will discuss the rationale of HSCT to treat MS by providing the benefits and complications of the clinically relevant protocols, the varying graft types, and conditioning regimens. However, we emphasize that future trials based on HSCT should be focused on specific therapeutic strategies to target and limit ongoing neurodegeneration and demyelination in progressive MS, in the hope that such treatment may serve a greater catchment of patient cohorts with potentially enhanced efficiency and lower toxicity. Despite these future ambitions, a proposed international multicenter, randomized clinical trial of HSCT should be governed by the best standard care of treatment, whereby MS patients are selected upon strict clinical course criteria and long-term follow-up studies of patients from international registries are imposed to advocate HSCT as a therapeutic option in the management of MS

Human mesenchymal stem cells alter macrophage phenotype and promote regeneration via homing to the kidney following ischemia-reperfusion injury

Mesenchymal stem cells (MSCs) ameliorate injury and accelerate repair in many organs, including the kidney, although the reparative mechanisms and interaction with macrophages have not been elucidated. This study investigated the reparative potential of human bone marrow-derived MSCs and traced their homing patterns following administration to mice with ischemia-reperfusion (IR) injury using whole body bioluminescence imaging. The effect of MSCs on macrophage phenotype following direct and indirect coculture was assessed using qPCR. Human cytokine production was measured using multiplex arrays. After IR, MSCs homed to injured kidneys where they afforded protection indicated by decreased proximal tubule kidney injury molecule-1 expression, blood urea nitrogen, and serum creatinine levels. SDS-PAGE and immunofluorescence labeling revealed MSCs reduced collagen α1(I) and IV by day 7 post-IR. Gelatin zymography confirmed that MSC treatment significantly increased matrix metalloproteinase-9 activity in IR kidneys, which contributed to a reduction in total collagen. Following direct and indirect coculture, macrophages expressed genes indicative of an anti-inflammatory "M2" phenotype. MSC-derived human GM-CSF, EGF, CXCL1, IL-6, IL-8, MCP-1, PDGF-AA, and CCL5 were identified in culture supernatants. In conclusion, MSCs home to injured kidneys and promote repair, which may be mediated by their ability to promote M2 macrophage polarization

Multilineage Potential and Self-Renewal Define an Epithelial Progenitor Cell Population in the Adult Thymus

Thymic epithelial cells (TECs) are critical for T cell development and self-tolerance but are gradually lost with age. The existence of thymic epithelial progenitors (TEPCs) in the postnatal thymus has been inferred, but their identity has remained enigmatic. Here, we assessed the entire adult TEC compartment in order to reveal progenitor capacity is retained exclusively within a subset of immature thymic epithelium displaying several hallmark features of stem/progenitor function. These adult TEPCs generate mature cortical and medullary lineages in a stepwise fashion, including Aire+ TEC, within fetal thymus reaggregate grafts. Although relatively quiescent in vivo, adult TEPCs demonstrate significant in vitro colony formation and self-renewal. Importantly, 3D-cultured TEPCs retain their capacity to differentiate into cortical and medullary TEC lineages when returned to an in vivo thymic microenvironment. No other postnatal TEC subset exhibits this combination of properties. The characterization of adult TEPC will enable progress in understanding TEC biology in aging and regeneration

Immune-phenotype and bone marrow (BM) progenitor status of naïve <i>ngr1-/-</i> and WT mice.

<p>(<b>A</b>) Comparative flow cytometric analysis of single cell suspension from spleen, BM, thymus, blood, lymph nodes and central nervous system (CNS) associated mononuclear cells. Proportion and total number of CD3⁺CD8⁺ and CD3⁺CD4⁺ T cells, B220⁺ B cells, Gr-1⁺ granulocytes and F4/80 (Gr-1^loF4/80⁺) monocyte/macrophage are shown. Data represent mean ± SEM (n = 8-11). *p&lt;0.05 Mann-Whitney test. (<b>B</b>) Quantification of BM-derived colony number in naïve <i>ngr1-/-</i> and WT mice<b>.</b> After 8 days on methylcellulose culture, BM-derived progenitors from <i>ngr1-/-</i> animals were capable of producing granulocytes (G); macrophages (M) and mixed (GM) colonies at comparable numbers to WT mice. Bars represent mean colony number/plate ± SEM (n = 3).</p

Immune-phenotype of <i>ngr1-/-</i> mice during EAE induced with rMOG.

<p><i>ngr1-/-</i> and WT animals were immunized with rMOG and the mononuclear cells isolated at 18 (peak) and 45 (chronic) days post-immunization (dpi) were analyzed by flow cytometry. Proportion and total number of lymphocytes, granulocytes and monocyte/macrophages of bone marrow (BM; <b>A</b>); spleen, (<b>B</b>); lymph nodes, (<b>C</b>); thymus (<b>D</b>) and central nervous system (CNS; <b>E</b>) are shown. No significant differences were found between <i>ngr1-/-</i> and WT for all organs and time points examined. Data represent mean ± SEM (n = 6-11). (<b>F</b>) Further analysis of microglia (CD45^loCD11b⁺) and macrophages (CD45^hiCD11b⁺) in the CNS of <i>ngr1-/-</i> and WT mice was performed. <i>ngr1-/-</i> animals presented an increased proportion of microglial cells at 18 dpi and a decreased number of macrophages at 45 dpi (n = 3-4; *p&lt; 0.05 Mann-Whitney test).</p