Human mesenchymal stem cells require monocyte-mediated activation to suppress alloreactive T cells
ABSTRACT Human bone marrow-derived mesenchymal cells (MSCs) are precursors of nonhematopoietic mesenchymal cells of the bone marrow microenvironment. MSCs were shown to inhibit alloreactive T lymphocytes, but the mechanism and mediators of this effect are not fully understood. Here we describe a novel interaction between blood monocytes and bone marrow-derived, culture-expanded MSCs, which results in inhibition of T-lymphocyte activation. We found that CD14+ monocytes from blood activate MSCs to secrete inhibitory molecules that lead to inhibition of alloreactive T cells. This cellular communication is not contact-dependent, but rather is mediated by soluble factors that include interleukin (IL)-1beta. MSC-mediated inhibition of alloreactive T lymphocytes is associated with downregulation of activation markers CD25, CD38, and CD69 detected both in CD4+ and CD8+ T lymphocytes. The cytokines secreted by MSCs that mediate T-cell inhibition include transforming growth factor-beta1, but not IL-10. The interaction between blood monocytes and the MSCs represents a unique immune regulatory paradigm that can potentially be exploited in clinic.
- SourceAvailable from: Felipe Saldanha-Araujo[Show abstract] [Hide abstract]
ABSTRACT: Mesenchymal stromal cells (MSCs) are multipotent cells, which can give rise to several cell types including osteoblasts, adipocytes, and chondroblasts. These cells can be found in a variety of adult and fetal tissues, such as bone marrow, adipose tissue, cord blood, and placenta. In recent years, the biological properties of MSCs have attracted the attention of researchers worldwide due to their potential application for treating a series of clinical situations. Among these properties, special attention should be given to the immunoregulatory potential of those cells. MSCs are able to act on all cells of the immune system, which includes the capacity to inhibit the proliferation and function of T-cells. This feature renders them natural candidates to treat several diseases in which cellular immune response is exacerbated. In this review, we outline the main mechanisms by which MSCs immunosuppress T-cell response, focusing on cell-cell contact, secretion of soluble factors, and regulatory T-cell generation. The influence of surface markers in the immunosuppression process and features of MSCs isolated from different sources are also discussed. Finally, the influences of toll-like receptors and cytokines on the inflammatory microenvironment are highlighted regarding the activation of MSCs to exert their immunoregulatory function.BioMed Research International 06/2014; 2014:216806. DOI:10.1155/2014/216806 · 2.71 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Stem cell therapies for musculoskeletal disorders are becoming commonplace in the horse. In order to decipher the many options available for stem cell therapy and interpret results of accumulating experimental and clinical data, practitioners should have a basic understanding of stem cells.06/2014; 26(9). DOI:10.1111/eve.12200
- [Show abstract] [Hide abstract]
ABSTRACT: Mesenchymal stromal cells (MSCs) are multipotent cells found in connective tissues that can differentiate into bone, cartilage, and adipose tissue. Interestingly, they can regulate immune responses in a paracrine way and allogeneic MSCs do not elicit immune response. These properties have encouraged a number of clinical trials in a broad range of regenerative therapies. Although these trials were first focused on their differentiation properties, in the last years, the immunosuppressive features have gained most of the attention. In this review, we will summarize the up-to-date knowledge about the immunosuppressive mechanisms of MSCs in vivo and in vitro and the most promising approaches in clinical investigation.09/2013; 2013:203643. DOI:10.1155/2013/203643