Neuralized mesenchymal stem cells (NMSC) exhibit phenotypical, and biological evidence of neuronal transdifferentiation and suppress EAE more effectively than unmodified MSC

Sox2-mediated transdifferentiation of hAT-MSCs into induced neural progenitor-like cells for remyelination therapies

Mesenchymal stem cells (MSCs) are converted to neural cells using growth factors and chemicals. Although these neural cells are effective at modulating disease symptoms, they are less effective at replacing lost neural cells. Direct transdifferentiation seems to be a promising method for generating the required cells for regenerative medicine applications. Sox2 is a key transcription factor in neural progenitor (NP) fate determination and has been frequently used for transdifferentiating different cell types to NPs. Here, we demonstrated that the overexpression of a single transcription factor, Sox2, in human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) led to the generation of induced NPs-like cells that were clonogenic, proliferative and passageable, and showed the potential to differentiate into three neural lineages. NPs are known as progenitors with the potential to differentiate into oligodendrocytes. In vivo, following transplantation into demyelinated adult mouse brains, they survived, differentiated and integrated into the adult brain while participating in the remyelination process and behavioral improvement. This report introduces a beneficial, low-cost and effective approach for generating NPs from an accessible adult source for autologous applications in treating neurodegenerative diseases, including remyelination therapies for multiple sclerosis and other demyelinating diseases.

Cell-based experimental strategies for myelin repair in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune demyelinating disorder of the central nervous system (CNS), diagnosed at a mean age of 32 years. CNS glia are crucial players in the onset of MS, primarily involving astrocytes and microglia that can cause/allow massive oligodendroglial cells death, without immune cell infiltration. Current therapeutic approaches are aimed at modulating inflammatory reactions during relapsing episodes, but lack the ability to induce very significant repair mechanisms. In this review article, different experimental approaches based mainly on the application of different cell types as therapeutic strategies applied for the induction of myelin repair and/or the amelioration of the disease are discussed. Regarding this issue, different cell sources were applied in various experimental models of MS, with different results, both in significant improvements in remyelination and the reduction of neuroinflammation and glial activation, or in neuroprotection. All cell types tested have advantages and disadvantages, which makes it difficult to choose a better option for therapeutic application in MS. New strategies combining cell-based treatment with other applications would result in further improvements and would be good candidates for MS cell therapy and myelin repair.

Stem Cells Attenuate the Inflammation Crosstalk Between Ischemic Stroke and Multiple Sclerosis: A Review

The immense neuroinflammation induced by multiple sclerosis (MS) promotes a favorable environment for ischemic stroke (IS) development, making IS a deadly complication of MS. The overlapping inflammation in MS and IS is a prelude to the vascular pathology, and an inherent cell death mechanism that exacerbates neurovascular unit (NVU) impairment in the disease progression. Despite this consequence, no therapies focus on reducing IS incidence in patients with MS. To this end, the preclinical and clinical evidence we review here argues for cell-based regenerative medicine that will augment the NVU dysfunction and inflammation to ameliorate IS risk.

Human Olfactory Mesenchymal Stem Cells Are a Novel Candidate for Neurological Autoimmune Disease

Background: Human olfactory mesenchymal stem cells (OMSC) have become a novel therapeutic option for immune disorder or demyelinating disease due to their immunomodulatory and regenerative potentials. However, the immunomodulatory effects of OMSC still need to be elucidated, and comparisons of the effects of different MSCs are also required in order to select an optimal cell source for further applications. Results: In animal experiments, we found neural functional recovery and delayed EAE attack in the OMSC treatment group. Compared with umbilical cord-derived mesenchymal stem cells (UMSC) treatment group and the control group, the OMSC treatment group had a better neurological improvement, lower serum levels of IFN-γ, and a lower proportion of CD4+IFN-γ+ T splenic lymphocyte. We also observed OMSC effectively suppressed CD4+IFN-γ+ T cell proportion in vitro when co-cultured with human peripheral blood-derived lymphocytes. The OMSC-mediated immunosuppressive effect on human CD4+IFN-γ+ T cells was attenuated by blocking cyclooxygenase activity. Conclusion: Our results suggest that OMSC treatment delayed the onset and promoted the neural functional recovery in the EAE mouse model possibly by suppressing CD4+IFN-γ+ T cells. OMSC transplantation might become an alternative therapeutic option for neurological autoimmune disease.

Human Fallopian Tube - Derived Mesenchymal Stem Cells Inhibit Experimental Autoimmune Encephalomyelitis by Suppressing Th1/Th17 Activation and Migration to Central Nervous System

Mesenchymal stem cells comprise a natural reservoir of undifferentiated cells within adult tissues. Given their self-renewal, multipotency, regenerative potential and immunomodulatory properties, MSCs have been reported as a promising cell therapy for the treatment of different diseases, including neurodegenerative and autoimmune diseases. In this study, we investigated the immunomodulatory properties of human tubal mesenchymal stem cells (htMSCs) using the EAE model. htMSCs were able to suppress dendritic cells activation downregulating antigen presentation-related molecules, such as MHCII, CD80 and CD86, while impairing IFN-γ and IL-17 and increasing IL-10 and IL-4 secretion. It further correlated with milder disease scores when compared to the control group due to fewer leukocytes infiltrating the CNS, specially Th1 and Th17 lymphocytes, associated with increased IL-10 secreting Tr1 cells. Conversely, microglia were less activated and infiltrating mononuclear cells secreted higher levels of IL-4 and IL-10 and expressed reduced chemokine receptors as CCR4, CCR6 and CCR8. qPCR of the spinal cords revealed upregulation of indoleamine-2,3-dioxygenase (IDO) and brain derived neurotrophic factor (BDNF). Taken together, here evidenced the potential of htMSCs as an alternative for the treatment of inflammatory, autoimmune or neurodegenerative diseases.

Therapeutic prospects of MicroRNAs carried by mesenchymal stem cells-derived extracellular vesicles in autoimmune diseases

Autoimmune diseases (ADs) are a class of chronic disease conditions with impaired tolerance to autoantigens. Currently, there is no effective treatment for ADs, and the existing medications have limitations due to non-specific targets and side effects. Accumulating evidence has shown that mesenchymal stem cells (MSCs) play a role in ADs treatment. These beneficial effects mainly rely on cell-to-cell communication through the secretion of extracellular vesicles (EVs) and soluble factors. MSC-derived EVs (MSC-EVs) could modulate adjacent and distinct cells by transferring various DNA, mRNA, non-coding RNAs, proteins, and lipids from parent cells to recipient cells. MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate multiple target genes at the post-transcriptional level and are involved in chronic inflammatory and immune processes. Compared to fluid, MSC-EVs delivery can protect miRNAs from the degradation of ribonucleases, ensuring that miRNAs are able to perform their respective crucial roles in AD recipient cells. In this review, we discussed the therapeutic prospects and challenges of miRNAs secreted by MSC-EVs (MSC-EV-miRNAs) by reviewing the experimentally verified therapeutic outcomes of MSC-EV-miRNAs for several ADs, including rheumatoid arthritis (RA), autoimmune hepatitis (AIH), asthma, colitis, systemic sclerosis (SSc) and graft-versus-host disease (GVHD).

Mesenchymal Stem Cells in Multiple Sclerosis: Recent Evidence from Pre-Clinical to Clinical Studies

Multiple sclerosis (MS) is an autoimmune, demyelinating disease of the central nervous system. Nowadays, available therapies for MS can help to manage MS course and symptoms, but new therapeutic approaches are required. Stem cell therapy using mesenchymal stem cells (MSCs) appeared promising in different neurodegenerative conditions, thanks to their beneficial capacities, including the immunomodulation ability, and to their secretome. The secretome is represented by growth factors, cytokines, and extracellular vesicles (EVs) released by MSCs. In this review, we focused on studies performed on in vivo MS models involving the administration of MSCs and on clinical trials evaluating MSCs administration. Experimental models of MS evidenced that MSCs were able to reduce inflammatory cell infiltration and disease score. Moreover, MSCs engineered to express different genes, preconditioned with different compounds, differentiated or in combination with other compounds also exerted beneficial actions in MS models, in some cases also superior to native MSCs. Secretome, both conditioned medium and EVs, also showed protective effects in MS models and appeared promising to develop new approaches. Clinical trials highlighted the safety and feasibility of MSC administration and reported some improvements, but other trials using larger cohorts of patients are needed.