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Duchenne muscular dystrophy (DMD) is a lethal X-linked musculodegenerative condition consisting of an underlying genetic defect whose manifestation is augmented by inflammatory mechanisms. Previous treatment approaches using gene replacement, exon-skipping or allogeneic cell therapy have been relatively unsuccessful. The only intervention to mediate improvement in survival, albeit minor, is glucocorticoid treatment. Given this modality appears to function via suppression of underlying inflammation; we focus this review on the inflammatory response as a target for mesenchymal stem cell (MSC) therapy. In contrast to other cell based therapies attempted in DMD, MSC have the advantages of (a) ability to fuse with and genetically complement dystrophic muscle; (b) possess anti-inflammatory activities; and (c) produce trophic factors that may augment activity of endogenous repair cells. We conclude by describing one practical scenario of stem cell therapy for DMD.

Since the days of Medawar, the goal of therapeutic tolerogenesis has been a "Holy Grail" for immunologists. While knowledge of cellular and molecular mechanisms of this process has been increasing at an exponential rate, clinical progress has been minimal. To provide a mechanistic background of tolerogenesis, we overview common processes in the naturally occurring examples of: pregnancy, cancer, oral tolerance and anterior chamber associated immune deviation. The case is made that an easily accessible byproduct of plastic surgery, the adipose stromal vascular fraction, contains elements directly capable of promoting tolerogenesis such as T regulatory cells and inhibitory macrophages. The high content of mesenchymal and hematopoietic stem cells from this source provides the possibility of trophic/regenerative potential, which would augment tolerogenic processes by decreasing ongoing inflammation. We discuss the application of this autologous cell source in the context of rheumatoid arthritis, concluding with some practical examples of its applications., (2010 Elsevier Inc. All rights reserved.)

Background: In transplantation, the antigen presentation step of T cell activation determines whether the T cell rejects the graft, ignores the graft, or inhibits other T cells from attacking the graft. Dendritic cells (DCs) are the most potent antigen presenting cells that are capable of activating naïve T cells. The purpose of the present study was to investigate the influence of anti-CD(45)RB monoclonal antibody on the phenotypes and functions of DCs and to further illustrate the mechanism of anti-CD(45)RB monoclonal antibody-inducing immunologic tolerance., Methods: DCs from mice were cultured and treated with varying doses of anti-CD(45)RB monoclonal antibody at specific time points. Fluorescence-activated cell sorting (FACS) was used to verify the changes of phenotypes in the cultured DCs labeled with fluorescent antibody. DCs were also used as stimulators in mixed leukocyte reaction to detect their ability to stimulate T cell proliferation., Results: Anti-CD(45)RB monoclonal antibody induced a dose- and time-dependent suppression of maturation of DCs and a dose-dependent suppression of T cell proliferation in mixed leukocyte reaction when anti-CD(45)RB monoclonal antibody-treated DCs were used as stimulators., Conclusions: One of the mechanisms of anti-CD(45)RB monoclonal antibody-induced tolerance was inhibiting maturation and function of DCs and inducing tolerogenic DCs to achieve a new immune balance.

Translation of small interfering RNA (siRNA)-based approaches into practical therapeutics is limited because of lack of an effective and cell-specific delivery system. Herein, we present a new method of selectively delivering siRNA to dendritic cells (DCs) in vivo using CD40 siRNA-containing immunoliposomes (siILs) that were decorated with DC-specific DEC-205 mAb. Administration of CD40 siILs resulted in DC-specific cell targeting in vitro and in vivo. On treatment with CD40 siILs, the expression of CD40 in DCs, as well allostimulatory activity was inhibited. In vivo administration resulted in selective siRNA uptake into immune organs and functional immune modulation as assessed using a model antigen. In conclusion, this is the first demonstration of DC-specific siRNA delivery and gene silencing in vivo, which highlights the potential of DC-mediated immune modulation and the feasibility of siRNA-based clinical therapy.

Background: A major barrier to clinical xenotransplantation is preformed xenoreactive natural antibodies (XNA) found in higher primates which react to Galalpha(1,3)Gal (alpha-Gal) epitopes found on lower species. Accommodation of organs to xenogeneic recipients involves upregulation of cytoprotective genes and resistance to complement dependent cytotoxicity (CDC)., Methods: To develop methods of increasing these organ-protective effects, we established an in vitro CDC model utilizing human serum as the source of XNA and porcine endothelial cells (pEC) as targets., Results: Using this system we demonstrated that downregulation of alpha-Gal epitopes by siRNA silencing of alpha1,3-galactosyltransferase (alpha-GT) led to marginal protection from CDC while alpha-Gal silencing combined with Griffonia simplicifolia isolectin B4 (GS-IB4), a lectin that specifically binds to alpha-Gal epitopes, led to complete protection. Interestingly, alpha-Gal silencing and GS-IB4 mediated effects were not associated with inhibition of XNA binding to cells, but with significant decreased E-selectin expression and cytoprotective gene HO-1 upregulation. PI3K inhibitor LY294002 could block the elevation of HO-1 protein expression and reverse the protective effect of alpha-Gal silencing and GS-IB4 against CDC., Conclusion: These data support the use of combination approaches targeting independent accommodation mechanisms to synergistically enhance donor organ survival in a xenogeneic setting.

Regenerative treatment of dilated, non-ischaemic cardiomyopathy represents a significant unmet clinical need. Intracoronary administration of autologous bone marrow stem cells has demonstrated positive results in treatment of post-infarct and chronic ischaemic patients. Limitations of this procedure include: invasiveness of bone marrow extraction and cardiac catheterization, and dependence on stem cell populations that are aged and possibly senescent. Here, the use of intravenously administered allogeneic placental matrix derived mesenchymal stem cells for treatment of dilated cardiomyopathy is discussed. Safety of this cell population has already been established in completed Phase I and II trials; however, to date, clinical implementation for dilated cardiomyopathy has not been reported. Preclinical studies have demonstrated that mesenchymal stem cells: (i) inhibit myocardial inflammation; (ii) inhibit cardiomyocyte apoptosis; (iii) stimulate angiogenesis; and (iv) display therapeutic activity in models of dilated cardiomyopathy. Clinical studies have demonstrated the ability of mesenchymal stem cells to inhibit post-infarct remodelling, as well as potently block inflammatory processes in graft versus host and Crohn disease. Presented here is case report of a patient with dilated cardiomyopathy treated with intravenous allogeneic mesenchymal stem cells and expanded umbilical cord blood CD34 cells who underwent a profound clinical improvement.

Brother of the regulator of imprinted sites (BORIS) is an epigenetically acting transcription factor which represses the tumor inhibitor functions of the tumor suppressor protein CTCF. BORIS expression has not been documented in adult females, making it an exciting molecular target for drug development in breast cancer. Previously, we demonstrated that vaccination of mice with zing-finger (ZF)-deleted non-functional BORIS results in regression of breast cancer and generation of potent anti-tumor immune responses. RNAi induction can be used as an alternative approach for selective tumor cell killing. Short interfering RNA (siRNA) molecules targeting BORIS were generated and their efficacy was tested in MDA-MB-231 breast cancer and non-malignant epithelial cell lines. Treatment with BORIS-specific siRNA, but not control siRNA led to a concentration-dependent reduction in BORIS expression and proportional apoptotic death of the cancer but not control cells. To our knowledge this is first report demonstrating a critical role of BORIS in maintaining tumor cell viability.

Mesenchymal stem cell (MSC) therapy is the most clinically advanced form of cell therapy, second to hematopoietic stem cell transplants. To date, MSC have been used for immune modulation in conditions such as Graft Versus Host Disease (GVHD) and Crohn's Disease, for which Phase III clinical trials are currently in progress. Here, we review the immunological properties of MSC and make a case for their use in treatment of Charcot-Marie-Tooth disease type 1 (CMT1), a group of inherited peripheral neuropathies. CMT1 is characterized by demyelination and aberrant immune activation making this condition an ideal target for exploration of MSC therapy, given the ability of these cells to promote sheath regeneration as well as suppress inflammation. Studies supporting this hypothesis will be presented and placed into the context of other cell-based approaches that are theoretically feasible. Given that MSCs selectively home to areas of inflammation, as well as exert effects in an allogeneic manner, the possibility of an "off the shelf" therapy for CMT1 will be discussed.

RNA interference (RNAi) is a process through which double-stranded RNA induces the activation of cellular pathways, leading to potent and selective silencing of genes with homology to the double strand. Much excitement surrounding small interfering RNA (siRNA)-mediated therapeutics arises from the fact that this approach overcomes many of the shortcomings previously experienced with approaches such as antibodies, antisense oligonucleotides and pharmacological inhibitors. Induction of RNAi through administration of siRNA has been successfully used in treatment of hepatitis, viral infections, and cancer. In this review we will present a brief history of RNAi, methods of inducing RNAi, application of RNAi in the therapeutic setting, and the possibilities of using this highly promising approach in the context of transplantation.

Achieving immunological tolerance in transplantation has been a long sought-after goal since the 1960s. It is, therefore, interesting that the dendritic cells (DC), which are classically known as the most potent stimulators of T cell activation, are now also considered putative tools for tolerance induction. In line with this, much work has been performed using DC for vaccination and immune stimulation. Recently, great interest has been generated regarding the ability of DC to act as immune regulatory cells. Specific subsets of DC or immature DC (iDC) appear to be responsible for maintaining self-tolerance. In this review we will highlight our efforts at elucidating the contribution of DC in transplant tolerant in mice. Specifically, four strategies will be outlined that are currently being used for the generation of DC that have tolerogenic properties in the prevention of allograft rejection. The present study demonstrates that modulated iDC with blunted T cell stimulatory or antigen presentation abilities can afford transplant tolerance by minimizing T cell activation and proinflammatory cytokine production. Moreover, in an alternate strategy, normally matured DC have also been modulated such that alloreactive T cells are specifically targeted for deletion.