We studied the immunoregulatory features of murine mesenchymal stem cells (MSCs) in vitro and in vivo. MSCs inhibited T-cell receptor (TCR)-dependent and -independent proliferation but did not induce apoptosis on T cells. Such inhibition was paired with a decreased interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha production and was partially reversed by interleukin-2 (IL-2). Thus, we used MSCs to treat myelin oligodendrocyte glycoprotein (MOG)35-55-induced experimental autoimmune encephalomyelitis (EAE) in C57BL/6J mice. We injected intravenously 1 ؋ 10 6 MSCs before disease onset (preventive protocol) and at different time points after disease occurrence (therapeutic protocol). MSC administration before disease onset strikingly ameliorated EAE. The therapeutic scheme was effective when MSCs were administered at disease onset and at the peak of disease but not after disease stabilization. Central nervous system (CNS) pathology showed decreased inflammatory infiltrates and demyelination in mice that received transplants of MSCs. T-cell response to MOG and mitogens from MSC-treated mice was inhibited and restored by IL-2 administration.

IntroductionAdult bone marrow stromal cells supply the appropriate scaffold for hematopoiesis 1 and hematopoietic-cell homeostasis, 2 but can also differentiate in vitro in most, if not all, somatic cell types. 3,4 Due to their specific capability of generating multiple mesenchymal lineages, bone marrow-derived stromal progenitors have been designated mesenchymal stem cells (MSCs). 5 MSCs are clonogenic because they can be isolated from bone marrow and expanded ex vivo without any apparent modification in phenotype or loss of function. Based on these features, MSCs are considered a promising strategy for tissue engineering, repair of damaged tissues, and gene therapy, but their capacity to trans-differentiate also in vivo is still unresolved.Recently, another unforeseen feature of MSCs has been reported, namely, that MSCs can modulate many T-cell functions including cell activation. 6,7 Based on this, human MSCs (hMSCs) have been administered in vivo to improve the outcome of allogeneic transplantation by promoting hematopoietic engraftment 8 and to hamper graft-versus-host disease. 9 More recently, we have shown that systemic administration of MSCs to mice affected by experimental autoimmune encephalomyelitis (EAE), a prototypical disease mediated by self-reactive T cells, results in striking disease amelioration mediated by the induction of peripheral tolerance. 10 In addition, it has been shown that tolerance induction by MSCs may occur also through the inhibition of dendritic-cell maturation and function, 11-13 thus suggesting that activated T cells are not the only targets of MSCs. In contrast, the effects of hMSCs on B cells are unknown.B-cell development occurs in the bone marrow and is strictly dependent on close interaction of B-cell progenitors with stromal cells that produce cytokines capable of supporting B-cell survival and proliferation. 14,15 Thus, we investigated whether MSCs, which derive from the marrow stroma, affect mature B-cell functions. Here, we demonstrate that hMSCs significantly affect proliferation, differentiation, and chemotactic behavior of normal mature B cells, thus further supporting the possibility that administration of MSCs may represent a novel therapeutic strategy for immune-mediated disorders. Materials and methodsAliquots of bone marrow aspirates were obtained from healthy adult bone marrow donors and peripheral-blood (PB) samples were obtained from healthy adult blood donors after informed consent was obtained, per the Declaration of Helsinki. The ethical board of the G. Gaslini Institute approved the study. B-cell isolation and cultureMononuclear cells (MNCs) were isolated by Ficoll-Hypaque density gradient (Sigma Chemical, St Louis, MO) from the PB of 9 healthy donors. Cell suspensions were first depleted of lymphocytes forming rosettes with sheep red blood cells (T cells) and subsequently treated with magnetic activated cell sorting (MACS) CD19-conjugated microbeads, according to the instructions of the manufacturer (Miltenyi Biotech, Auburn, CA). (mAb). All cell cul...

Overall, these findings suggest that the beneficial effect of MSCs in experimental autoimmune encephalomyelitis is mainly the result of an interference with the pathogenic autoimmune response.

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.