Mesenchymal stem cell transplantation reverses multiorgan dysfunction in systemic lupus erythematosus mice and humans

Critical Role of Tumor Necrosis Factor Signaling in Mesenchymal Stem Cell-Based Therapy for Autoimmune and Inflammatory Diseases

Mesenchymal stem cells (MSCs) have been broadly used as a therapy for autoimmune disease in both animal models and clinical trials. MSCs inhibit T effector cells and many other immune cells, while activating regulatory T cells, thus reducing the production of pro-inflammatory cytokines, including tumor necrosis factor (TNF), and repressing inflammation. TNF can modify the MSC effects via two TNF receptors, i.e., TNFR1 in general mediates pro-inflammatory effects and TNFR2 mediates anti-inflammatory effects. In the central nervous system, TNF signaling plays a dual role, which enhances inflammation via TNFR1 on immune cells while providing cytoprotection via TNFR2 on neural cells. In addition, the soluble form of TNFR1 and membrane-bound TNF also participate in the regulation to fine-tune the functions of target cells. Other factors that impact TNF signaling and MSC functions include the gender of the host, disease course, cytokine concentrations, and the length of treatment time. This review will introduce the fascinating progress in this aspect of research and discuss remaining questions and future perspectives.

Eminent Sources of Adult Mesenchymal Stem Cells and Their Therapeutic Imminence

In the recent times, stem cell biology has garnered the attention of the scientific fraternity and the general public alike due to the immense therapeutic potential that it holds in the field of regenerative medicine. A breakthrough in this direction came with the isolation of stem cells from human embryo and their differentiation into cell types of all three germ layers. However, the isolation of mesenchymal stem cells from adult tissues proved to be advantageous over embryonic stem cells due to the ethical and immunological naivety. Mesenchymal Stem Cells (MSCs) isolated from the bone marrow were found to differentiate into multiple cell lineages with the help of appropriate differentiation factors. Furthermore, other sources of stem cells including adipose tissue, dental pulp, and breast milk have been identified. Newer sources of stem cells have been emerging recently and their clinical applications are also being studied. In this review, we examine the eminent sources of Mesenchymal Stem Cells (MSCs), their immunophenotypes, and therapeutic imminence.

Effect of a Combination of Prednisone or Mycophenolate Mofetil and Mesenchymal Stem Cells on Lupus Symptoms in MRL.Faslpr Mice

The combination of immunosuppressants and mesenchymal stem cells (MSCs) is a promising therapeutic strategy for systemic lupus erythematosus, since this approach reduces doses of immunosuppressants while maintaining the same therapeutic outcome. However, it is unavoidable for MSCs to be exposed to immunosuppressants. Here, we examined the combination effect of prednisone (PD) or mycophenolate mofetil (MMF) and MSCs. We showed that PD or MMF in combination with MSCs showed better therapeutic effect than single therapy in lupus-prone MRL.Fas^lpr mice, as assessed by using the following readouts: prolongation of survival, decrease in anti-dsDNA and total IgG levels in serum, decrease in cytokine gene expression in spleen cells, and decrease in inflammatory cell infiltration into the kidney. In vitro, immunosuppressants and MSCs inhibited T cell proliferation in a synergistic manner. However, immunosuppressants did not affect MSC viability and functions such as TGF-β1 and PGE₂ production, migration, and immunosuppressive capacity. In summary, our study demonstrates that a combination of immunosuppressants and MSCs is a good strategy to reduce the side effects of PD and MMF without the loss of therapeutic outcome.

Stem Cells in Dentistry: Types of Intra- and Extraoral Tissue-Derived Stem Cells and Clinical Applications

Stem cells are undifferentiated cells, capable of renewing themselves, with the capacity to produce different cell types to regenerate missing tissues and treat diseases. Oral facial tissues have been identified as a source and therapeutic target for stem cells with clinical interest in dentistry. This narrative review report targets on the several extraoral- and intraoral-derived stem cells that can be applied in dentistry. In addition, stem cell origins are suggested in what concerns their ability to differentiate as well as their particular distinguishing quality of convenience and immunomodulatory for regenerative dentistry. The development of bioengineered teeth to replace the patient's missing teeth was also possible because of stem cell technologies. This review will also focus our attention on the clinical application of stem cells in dentistry. In recent years, a variety of articles reported the advantages of stem cell-based procedures in regenerative treatments. The regeneration of lost oral tissue is the target of stem cell research. Owing to the fact that bone imperfections that ensue after tooth loss can result in further bone loss which limit the success of dental implants and prosthodontic therapies, the rehabilitation of alveolar ridge height is prosthodontists' principal interest. The development of bioengineered teeth to replace the patient's missing teeth was also possible because of stem cell technologies. In addition, a “dental stem cell banking” is available for regenerative treatments in the future. The main features of stem cells in the future of dentistry should be understood by clinicians.

Mesenchymal Stem Cells Control Complement C5 Activation by Factor H in Lupus Nephritis

Lupus nephritis (LN) is one of the most severe complications of systemic lupus erythematosus (SLE) caused by uncontrolled activation of the complement system. Mesenchymal stem cells (MSCs) exhibit clinical efficacy for severe LN in our previous studies, but the underlying mechanisms of MSCs regulating complement activation remain largely unknown. Here we show that significantly elevated C5a and C5b-9 were found in patients with LN, which were notably correlated with proteinuria and different renal pathological indexes of LN. MSCs suppressed systemic and intrarenal activation of C5, increased the plasma levels of factor H (FH), and ameliorated renal disease in lupus mice. Importantly, MSCs transplantation up-regulated the decreased FH in patients with LN. Mechanistically, interferon-α enhanced the secretion of FH by MSCs. These data demonstrate that MSCs inhibit the activation of pathogenic C5 via up-regulation of FH, which improves our understanding of the immunomodulatory mechanisms of MSCs in the treatment of lupus nephritis.

Tet1 and Tet2 maintain mesenchymal stem cell homeostasis via demethylation of the P2rX7 promoter

Ten-eleven translocation (Tet) family-mediated DNA oxidation represents an epigenetic modification capable of converting 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC), which regulates various biological processes. However, it is unknown whether Tet family affects mesenchymal stem cells (MSCs) or the skeletal system. Here we show that depletion of Tet1 and Tet2 results in impaired self-renewal and differentiation of bone marrow MSCs (BMMSCs) and a significant osteopenia phenotype. Tet1 and Tet2 deficiency reduces demethylation of the P2rX7 promoter and downregulates exosome release, leading to intracellular accumulation of miR-297a-5p, miR-297b-5p, and miR-297c-5p. These miRNAs inhibit Runx2 signaling to impair BMMSC function. We show that overexpression of P2rX7 rescues the impaired BMMSCs and osteoporotic phenotype in Tet1 and Tet2 double knockout mice. These results indicate that Tet1 and Tet2 play a critical role in maintaining BMMSC and bone homeostasis through demethylation of P2rX7 to control exosome and miRNA release. This Tet/P2rX7/Runx2 cascade may serve as a target for the development of novel therapies for osteopenia disorders.

Tet-mediated DNA oxidation converts 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC), which is essential to regulate different biological processes. Here the authors show that Tet1 and Tet2 regulate mesenchymal stem cell and bone homeostasis through demethylation of P2rX7 promoter.

MicroRNA-21 Mediates the Protective Effects of Mesenchymal Stem Cells Derived from iPSCs to Human Bronchial Epithelial Cell Injury Under Hypoxia

Airway epithelial cell injury is a key triggering event to activate allergic airway inflammation, such as asthma. We previously reported that administration of mesenchymal stem cells (MSCs) significantly alleviated allergic inflammation in a mouse model of asthma, and the mmu-miR-21/ACVR2A axis may be involved. However, whether MSCs protect against bronchial epithelial cell injury induced by hypoxia, and the underlying mechanism, remain unknown. In our study, the human bronchial epithelial cell line BEAS-2B was induced to undergo apoptosis with a hypoxia mimic of cobalt chloride (CoCl₂) damage. Treatment of MSCs derived from induced pluripotent stem cells (iPSCs) significantly decreased apoptosis of BEAS-2B cells. There was high miR-21 expression in injured BEAS-2B cells after MSC treatment. Transfection of the miR-21 mimic significantly decreased apoptosis of BEAS-2B, and transfection of a miR-21 inhibitor significantly increased apoptosis. More importantly, the protective effects of MSCs on injured BEAS-2B were reversed by transfection of the miR-21 inhibitor. Binding sites of human miR-21 were identified in the 3’UTR of human ACVR2A. We further determined that CoCl₂ stimulation increased ACVR2A expression at both the mRNA and protein levels. Moreover, transfection of the miR-21 mimic further up-regulated ACVR2A expression induced by CoCl₂, whereas transfection of the miR-21 inhibitor down-regulated ACVR2A expression. In addition, MSCs increased ACVR2A expression in BEAS-2B cells; however, this effect was reversed after transfection of the miR-21 inhibitor. Our data suggested that MSCs protect bronchial epithelial cells from hypoxic injury via miR-21, which may represent an important target. These findings suggest the potentially wide application of MSCs for epithelial cell injury during hypoxia.

Genetic contribution to mesenchymal stem cell dysfunction in systemic lupus erythematosus

Allogeneic mesenchymal stem cell (MSC) transplantation has recently become a promising therapy for patients with systemic lupus erythematosus (SLE). MSCs are a kind of multipotent stem cell than can efficiently modulate both innate and adaptive immune responses, yet those from SLE patients themselves fail to maintain the balance of immune cells, which is partly due to the abnormal genetic background. Clarifying genetic factors associated with MSC dysfunction may be helpful to delineate SLE pathogenesis and provide new therapeutic targets. In this review, the scientific evidence on the genetic contribution to MSC dysfunction in SLE is summarized.

Therapeutic Delivery Specifications Identified Through Compartmental Analysis of a Mesenchymal Stromal Cell-Immune Reaction

Despite widespread preclinical success, mesenchymal stromal cell (MSC) therapy has not reached consistent pivotal clinical endpoints in primary indications of autoinflammatory diseases. Numerous studies aim to uncover specific mechanisms of action towards better control of therapy using in vitro immunomodulation assays. However, many of these immunomodulation assays are imperfectly designed to accurately recapitulate microenvironment conditions where MSCs act. To increase our understanding of MSC efficacy, we herein conduct a systems level microenvironment approach to define compartmental features that can influence the delivery of MSCs' immunomodulatory effect in vitro in a more quantitative manner than ever before. Using this approach, we notably uncover an improved MSC quantification method with predictive cross-study applicability and unveil the key importance of system volume, time exposure to MSCs, and cross-communication between MSC and T cell populations to realize full therapeutic effect. The application of these compartmental analysis can improve our understanding of MSC mechanism(s) of action and further lead to administration methods that deliver MSCs within a compartment for predictable potency.

Double-Edged Effect of Hydroxychloroquine on Human Umbilical Cord-Derived Mesenchymal Stem Cells Treating Lupus Nephritis in MRL/lpr Mice

Hydroxychloroquine (HCQ) and human umbilical cord-derived mesenchymal stem cells (UC-MSCs) were used to treat systemic lupus erythematosus (SLE), respectively. However, the effect of HCQ on UC-MSCs in lupus nephritis (LN) has not been investigated. In this study, HCQ and UC-MSCs were used in MRL/lpr mice. Surprisingly, although the treatment of both HCQ and UC-MSCs could ameliorate renal damage separately, the presence of HCQ decreased unexpectedly the therapeutic effects of UC-MSCs through interfering expression of IFN-γ. However, HCQ-pretreated UC-MSCs showed significant improvements of renal morphology and function more rapidly than that of UC-MSCs and HCQ alone. To test the role of HCQ in UC-MSCs, MRL/lpr mice and SLE patients' peripheral blood were used in vivo and in vitro. Results showed that after administration of UC-MSCs pretreated by HCQ, CXCR3 expression in renal tissues, serum IL-2, and IgM levels decreased significantly, and serum IL-10 level increased significantly. HCQ pretreatment caused a significant decrease of TNF-α and MCP-1 secretion and an increase of IL-1β and CXCL10 release from UC-MSCs. Our results indicate that HCQ plays a double-edged role in UC-MSCs. It is necessary for clinical treatment to pre-evaluated concomitant application of UC-MSCs with HCQ. More importantly, the alterative expression of IFN-γ, the improvement of migration ability of UC-MSCs, the regulation of Th1/Th2 balance, and the changes of antibodies secretion in B cell might be involved in its mechanisms.

Mesenchymal stem cell transplantation in systemic lupus erythematous, a mesenchymal stem cell disorder

Systemic lupus erythematosus (SLE) is a chronic autoimmune and inflammatory disorder with involvement of several organs and systems such as the kidney, lung, brain and the hematopoietic system. As the most prevailing organ manifestation, lupus nephritis is the major cause of mortality and morbidity in SLE patients. The most classically and widely administered immunosuppressive medications, namely corticosteroids and cyclophosphamide, have eventuated in a remarkable amelioration in disease complications over the last few years and reduced the progression to end-stage multiorgan failure. Mesenchymal stem cells (MSCs) are considered as non-hematopoietic and multipotential progenitor cells, which are able to differentiate into multiple cell lineages such as chondrocytes, osteoblasts, myoblasts, endothelial cells, adipocytes, neuron-like cells, hepatocytes and cardiomyocytes. MSCs from SLE patients have demonstrated defects such as aberrant cytokine production. Moreover, impaired phenotype, growth and immunomodulatory functions of MSCs from patients with SLE in comparison to healthy controls have been reported. Therefore, it is hypothesized that SLE is potentially an MSC-mediated disease and, as a result, allogeneic rather than autologous MSC transplantation can be argued to be a potentially advantageous therapy for patients with SLE. On the other hand, the MSC senescence phenomenon may meet the current therapeutic approaches with challenges and demand more attention. Here, we discuss MSC transplantations to date in animal models and humans and focus on the MSC senescence complications in SLE patients.

Successful mesenchymal stem cell treatment of leg ulcers complicated by Behcet disease: A case report and literature review

RATIONALE

Behçet disease (BD) is a recurrent vasculitis characterized by oral and genital mucous membrane ulcers, uveitis, and skin lesions but only rarely leg ulcers. To our knowledge, no efficacious therapy has been described for BD patients with complicating, destructive leg ulcers.

PATIENT CONCERNS

Here, We report the case of a 55-year-old woman with generalized erythema nodosum-like, papulopustular lesions, recurrent oral and genital ulcers accompanied with recurrent leg ulcers and trouble walking.

DIAGNOSES

Based upon the patient's clinical feature and positive pathergy test , BD was confirmed.

INTERVENTIONS

Conventional immunosuppressive therapy and anti-tumor necrosis factor inhibitors, adalimumab and etanercept, had no demonstrable clinical effect. Mesenchymal stem cell (MSC) injection combined with low-dose prednisone and thalidomide, however, completely ameliorated the ulcers on one leg, significantly improved ulcers on the other leg, and returned normal function to both legs.

OUTCOMES

The ulcerative lesions remained in remission, and the affected leg functioned normally after 34 months' follow-up.

LESSONS

Our experience suggests that MSC infusion might be a potentially successful therapy for intractable drug-resistant BD patients with concomitant leg ulcer.

L-Glutamine in vitro Modulates some Immunomodulatory Properties of Bone Marrow Mesenchymal Stem Cells

Glutamine (GLUT) is a nonessential amino acid that can become conditionally essential under stress conditions, being able to act in the modulation of the immune responses. Mesenchymal stem cells (MSCs) are known to their capability in the modulation of immune responses through cell-cell contact and by the secretion of soluble factors. Considering that GLUT is an immunonutrient and little is known about the influence of GLUT on the capability of MSCs to modulate immune cells, this work aims to investigate how variations in GLUT concentrations in vitro could affect some immunomodulatory properties of MSCs. In order to evaluate the effects of GLUT on MSCs immunomodulatory properties, cell proliferation rates, the expression of NFκB and STAT-3, and the production of IL-1β, IL-6, IL-10, TGF-β and TNF-α by MSCs were assessed. Based on our findings, GLUT at high doses (10 mM) augmented the proliferation of MSCs and modulated immune responses by decreasing levels of pro-inflammatory cytokines, such as IL-1β and IL-6, and by increasing levels of anti-inflammatory cytokines IL-10 and TGF-β. In addition, MSCs cultured in higher GLUT concentrations (10 mM) expressed lower levels of NF-κB and higher levels of STAT-3. Furthermore, conditioned media from MSCs cultured at higher GLUT concentrations (10 mM) reduced lymphocyte and macrophage proliferation, increased IL-10 production by both cells types, and decreased IFN-γ production by lymphocytes. Overall, this study showed that 10 mM of GLUT is able to modify immunomodulatory properties of MSCs.

The Fas/Fap-1/Cav-1 complex regulates IL-1RA secretion in mesenchymal stem cells to accelerate wound healing

Mesenchymal stem cells (MSCs) are capable of secreting exosomes, extracellular vesicles, and cytokines to regulate cell and tissue homeostasis. However, it is unknown whether MSCs use a specific exocytotic fusion mechanism to secrete exosomes and cytokines. We show that Fas binds with Fas-associated phosphatase-1 (Fap-1) and caveolin-1 (Cav-1) to activate a common soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE)-mediated membrane fusion mechanism to release small extracellular vesicles (sEVs) in MSCs. Moreover, we reveal that MSCs produce and secrete interleukin-1 receptor antagonist (IL-1RA) associated with sEVs to maintain rapid wound healing in the gingiva via the Fas/Fap-1/Cav-1 cascade. Tumor necrosis factor-α (TNF-α) serves as an activator to up-regulate Fas and Fap-1 expression via the nuclear factor κB pathway to promote IL-1RA release. This study identifies a previously unknown Fas/Fap-1/Cav-1 axis that regulates SNARE-mediated sEV and IL-1RA secretion in stem cells, which contributes to accelerated wound healing.

Hydrogen sulfide promotes immunomodulation of gingiva-derived mesenchymal stem cells via the Fas/FasL coupling pathway

BACKGROUND

Mesenchymal stem cells derived from gingiva (GMSCs) display profound immunomodulation properties in addition to self-renewal and multilineage differentiation capacities. Hydrogen sulfide (H₂S) is not only an environmental pollutant, but also is an important biological gas transmitter in health and disease.

METHODS

We used an in-vitro coculture system and a mouse colitis model to compare the immunomodulatory effects between control and H₂S-deficient GMSCs. The flow cytometry analysis was used for T-cell apoptosis and T-helper 17 (Th17) and regulatory T (Treg) cell differentiation.

RESULTS

We revealed that GMSCs exerted their immunomodulatory effect by inducing T-cell apoptosis, promoting Treg cell polarization, and inhibiting Th17 cell polarization in vitro. The levels of H₂S regulated the immunomodulatory effect of GMSCs. Mechanically, H₂S deficiency downregulated the expression of Fas in GMSCs, resulting in reduced secretion of monocyte chemotactic protein 1 (MCP-1), which in turn led to decreased T-cell migration to GMSCs mediated by MCP-1. Moreover, H₂S deficiency downregulated the expression of Fas ligand (FasL) in GMSCs. The Fas/FasL coupling-induced T-cell apoptosis by GMSCs was attenuated in H₂S-deficient GMSCs. Consistent with this, H₂S-deficient GMSCs showed attenuated therapeutic effects on colitis in vivo, which could be restored by treatment with the H₂S donor, NaHS.

CONCLUSIONS

These findings showed that H₂S was required to maintain immunomodulation of GMSCs, which was mediated by Fas/FasL coupling-induced T-cell apoptosis.

IL-17 down-regulates the immunosuppressive capacity of olfactory ecto-mesenchymal stem cells in murine collagen-induced arthritis

Olfactory ecto-mesenchymal stem cells (OE-MSCs) are a population of cells which has been recognized as a new resident stem cell type in the olfactory lamina propria. OE-MSCs have been shown to exert their immunosuppressive capacity by modulating T cell responses, including up-regulation of regulatory T cells (Tregs) and down-regulation of Th1/Th17 cells. As an inflammatory cytokine, IL-17 plays a critical role in orchestrating the inflammatory response during the development of collagen-induced arthritis (CIA). However, it is unclear whether the increased level of IL-17 may affect the immunosuppressive function of OE-MSCs under inflammatory condition. In this study, we found that IL-17 could significantly reduce the suppressive capacity of OE-MSCs on CD4+ T cells and down-regulate the suppressive factors produced by OE-MSCs. Notably, IL-17 treatment abolished the capacity of OE-MSCs in inducing Treg expansion. In addition, knockdown of IL-17R in OE-MSCs significantly enhanced their therapeutic effect in ameliorating CIA upon adoptive transfer. Moreover, IL-17R knockdown-OE-MSCs could efficiently induce Tregs expansion and reduce Th1 and Th17 responses. Taken together, all these data suggest that IL-17R knockdown in OE-MSCs may provide a novel strategy in maintaining their immunosuppressive properties for the treatment of autoimmune diseases.

Intraarticularly-Injected Mesenchymal Stem Cells Stimulate Anti-Inflammatory Molecules and Inhibit Pain Related Protein and Chondrolytic Enzymes in a Monoiodoacetate-Induced Rat Arthritis Model

Persistent inflammation is well known to promote the progression of arthropathy. mesenchymal stem cells (MSCs) have been shown to possess anti-inflammatory properties and tissue differentiation potency. Although the experience so far with the intraarticular administration of mesenchymal stem cell (MSC) to induce cartilage regeneration has been disappointing, MSC implantation is now being attempted using various surgical techniques. Meanwhile, prevention of osteoarthritis (OA) progression and pain control remain important components of the treatment of early-stage OA. We prepared a shoulder arthritis model by injecting monoiodoacetate (MIA) into a rat shoulder, and then investigated the intraarticular administration of MSC from the aspects of the cartilage protective effect associated with their anti-inflammatory property and inhibitory effect on central sensitization of pain. When MIA was administered in this rat shoulder arthritis model, anti-Calcitonin Gene Related Peptide (CGRP) was expressed in the joint and C5 spinal dorsal horn. Moreover, expression of A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), a marker of joint cartilage injury, was similarly elevated following MIA administration. When MSC were injected intraarticularly after MIA, the expression of CGRP in the spinal dorsal horn was significantly deceased, indicating suppression of the central sensitization of pain. The expression of ADAMTS 5 in joint cartilage was also significantly inhibited by MSC administration. In contrast, a significant increase in the expression of TNF-α stimulated gene/protein 6 (TSG-6), an anti-inflammatory and cartilage protective factor shown to be produced and secreted by MSC intraarticularly, was found to extend to the cartilage tissue following MSC administration. In this way, the intraarticular injection of MSC inhibited the central sensitization of pain and increased the expression of the anti-inflammatory and cartilage protective factor TSG-6. As the least invasive conservative strategies possible are desirable in the actual clinical setting, the intraarticular administration of MSC, which appears to be effective for the treatment of pain and cartilage protection in early-stage arthritis, may achieve these aims.

Genetically‑modified stem cells in treatment of human diseases: Tissue kallikrein (KLK1)‑based targeted therapy (Review)

The tissue kallikrein-kinin system (KKS) is an endogenous multiprotein metabolic cascade which is implicated in the homeostasis of the cardiovascular, renal and central nervous system. Human tissue kallikrein (KLK1) is a serine protease, component of the KKS that has been demonstrated to exert pleiotropic beneficial effects in protection from tissue injury through its anti-inflammatory, anti-apoptotic, anti-fibrotic and anti-oxidative actions. Mesenchymal stem cells (MSCs) or endothelial progenitor cells (EPCs) constitute populations of well-characterized, readily obtainable multipotent cells with special immunomodulatory, migratory and paracrine properties rendering them appealing potential therapeutics in experimental animal models of various diseases. Genetic modification enhances their inherent properties. MSCs or EPCs are competent cellular vehicles for drug and/or gene delivery in the targeted treatment of diseases. KLK1 gene delivery using adenoviral vectors or KLK1 protein infusion into injured tissues of animal models has provided particularly encouraging results in attenuating or reversing myocardial, renal and cerebrovascular ischemic phenotype and tissue damage, thus paving the way for the administration of genetically modified MSCs or EPCs with the human tissue KLK1 gene. Engraftment of KLK1-modified MSCs and/or KLK1-modified EPCs resulted in advanced beneficial outcome regarding heart and kidney protection and recovery from ischemic insults. Collectively, findings from pre-clinical studies raise the possibility that tissue KLK1 may be a novel future therapeutic target in the treatment of a wide range of cardiovascular, cerebrovascular and renal disorders.

Historical Perspectives and Advances in Mesenchymal Stem Cell Research for the Treatment of Liver Diseases

Liver transplantation is the only effective therapy for patients with decompensated cirrhosis and fulminant liver failure. However, due to a shortage of donor livers and complications associated with immune suppression, there is an urgent need for new therapeutic strategies for patients with end-stage liver diseases. Given their unique function in self-renewal and differentiation potential, stem cells might be used to regenerate damaged liver tissue. Recent studies have shown that stem cell-based therapies can improve liver function in a mouse model of hepatic failure. Moreover, acellular liver scaffolds seeded with hepatocytes produced functional bioengineered livers for organ transplantation in preclinical studies. The therapeutic potential of stem cells or their differentiated progenies will depend on their capacity to differentiate into mature and functional cell types after transplantation. It will also be important to devise methods to overcome their genomic instability, immune reactivity, and tumorigenic potential. We review directions and advances in the use of mesenchymal stem cells and their derived hepatocytes for liver regeneration. We also discuss the potential applications of hepatocytes derived from human pluripotent stem cells and challenges to using these cells in treating end-stage liver disease.

Autologous Mesenchymal Stem Cell and Islet Cotransplantation: Safety and Efficacy

Islet engraftment after transplantation is impaired by high rates of islet/β cell death caused by cellular stressors and poor graft vascularization. We studied whether cotransplantation of ex vivo expanded autologous bone marrow-derived mesenchymal stem cells (MSCs) with islets is safe and beneficial in chronic pancreatitis patients undergoing total pancreatectomy with islet autotransplantation. MSCs were harvested from the bone marrow of three islet autotransplantation patients and expanded at our current Good Manufacturing Practices (cGMP) facility. On the day of islet transplantation, an average dose of 20.0 ± 2.6 ×106 MSCs was infused with islets via the portal vein. Adverse events and glycemic control at baseline, 6, and 12 months after transplantation were compared with data from 101 historical control patients. No adverse events directly related to the MSC infusions were observed. MSC patients required lower amounts of insulin during the peritransplantation period (p = .02 vs. controls) and had lower 12-month fasting blood glucose levels (p = .02 vs. controls), smaller C-peptide declines over 6 months (p = .01 vs. controls), and better quality of life compared with controls. In conclusion, our pilot study demonstrates that autologous MSC and islet cotransplantation may be a safe and potential strategy to improve islet engraftment after transplantation. (Clinicaltrials.gov registration number: NCT02384018). Stem Cells Translational Medicine 2018;7:11-19.

Mesenchymal stromal cells for tolerance induction in organ transplantation

The primary challenge in organ transplantation continues to be the need to suppress the host immune system long-term to ensure prolonged allograft survival. Long-term non-specific immunosuppression can, however, result in life-threatening complications. Thus, efforts have been pursued to explore novel strategies that would allow minimization of maintenance immunosuppression, eventually leading to transplant tolerance. In this scenario, bone marrow-derived mesenchymal stromal cells (MSC), given their unique immunomodulatory properties to skew the balance between regulatory and memory T cells, have emerged as potential candidates for cell-based therapy to promote immune tolerance. Here, we review our initial clinical experience with bone marrow-derived MSC in living-donor kidney transplant recipients and provide an overview of the available results of other clinical programs with MSC in kidney and liver transplantation, highlighting hurdles and success of this innovative cell-based therapy.

Effects of low-intensity pulsed ultrasound (LIPUS)-pretreated human amnion-derived mesenchymal stem cell (hAD-MSC) transplantation on primary ovarian insufficiency in rats

BACKGROUND

Human amnion-derived mesenchymal stem cells (hAD-MSCs) have the features of mesenchymal stem cells (MSCs). Low-intensity pulsed ultrasound (LIPUS) can promote the expression of various growth factors and anti-inflammatory molecules that are necessary to keep the follicle growing and to reduce granulosa cell (GC) apoptosis in the ovary. This study aims to explore the effects of LIPUS-pretreated hAD-MSC transplantation on chemotherapy-induced primary ovarian insufficiency (POI) in rats.

METHODS

The animals were divided into control, POI, hAD-MSC treatment, and LIPUS-pretreated hAD-MSC treatment groups. POI rat models were established by intraperitoneal injection of cyclophosphamide (CTX). The hAD-MSCs isolated from the amnion were exposed to LIPUS or sham irradiation for 5 consecutive days and injected into the tail vein of POI rats. Expression and secretion of growth factors promoted by LIPUS in hAD-MSCs were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) in vitro. Estrous cycle, serum sex hormone levels, follicle counts, ovarian pathological changes, GC apoptosis, Bcl2 and Bax expression, and pro-inflammatory cytokine levels in ovaries were examined.

RESULTS

Primary hAD-MSCs were successfully isolated from the amnion. LIPUS promoted the expression and secretion of growth factors in hAD-MSCs in vitro. Both hAD-MSC and LIPUS-pretreated hAD-MSC transplantation increased the body and reproductive organ weights, improved ovarian function, and reduced reproductive organ injuries in POI rats. Transplantation of hAD-MSCs increased the Bcl-2/Bax ratio and reduced GC apoptosis and ovarian inflammation induced by chemotherapy in ovaries. These effects could be improved by pretreatment with LIPUS on hAD-MSCs.

CONCLUSION

Both hAD-MSC transplantation and LIPUS-pretreated hAD-MSC transplantation can repair ovarian injury and improve ovarian function in rats with chemotherapy-induced POI. LIPUS-pretreated hAD-MSC transplantation is more advantageous for reducing inflammation, improving the local microenvironment, and inhibiting GC apoptosis induced by chemotherapy in ovarian tissue of POI rats.

Mesenchymal Stem Cells in Kidney Repair

Every year 13.3 million people suffer acute kidney injury (AKI), which is associated with a high risk of death or development of long-term chronic kidney disease (CKD) in a substantial percentage of patients besides other organ dysfunctions. To date, the mortality rate per year for AKI exceeds 50 % at least in patients requiring early renal replacement therapy and is higher than the mortality for breast and prostate cancer, heart failure and diabetes combined.Until now, no effective treatments able to accelerate renal recovery and improve survival post AKI have been developed. In search of innovative and effective strategies to foster the limited regeneration capacity of the kidney, several studies have evaluated the ability of mesenchymal stem cells (MSCs) of different origin as an attractive therapeutic tool. The results obtained in several models of AKI and CKD document that MSCs have therapeutic potential in repair of renal injury, preserving renal function and structure thus prolonging animal survival through differentiation-independent pathways. In this chapter, we have summarized the mechanisms underlying the regenerative processes triggered by MSC treatment, essentially due to their paracrine activity. The capacity of MSC to migrate to the site of injury and to secrete a pool of growth factors and cytokines with anti-inflammatory, mitogenic, and immunomodulatory effects is described. New modalities of cell-to-cell communication via the release of microvesicles and exosomes by MSCs to injured renal cells will also be discussed. The translation of basic experimental data on MSC biology into effective care is still limited to preliminary phase I clinical trials and further studies are needed to definitively assess the efficacy of MSC-based therapy in humans.

Clinical Translation of Mesenchymal Stromal Cell Therapies in Nephrology

Mesenchymal stromal cells have emerged as potential candidates for cell-based therapies to modulate the immune response in organ transplantation and repair tissues after acute or chronic injury. Preclinical studies have shown convincingly in rodent models that mesenchymal stromal cells can prolong solid organ graft survival and that they can induce immune tolerance, accelerate recovery from AKI, and promote functional improvement in chronic nephropathies. Multiple complex properties of the cells, including immunomodulatory, anti-inflammatory, and proregenerative effects, seem to contribute. The promising preclinical studies have encouraged investigators to explore the safety, tolerability, and efficacy of mesenchymal stromal cell-based therapy in pilot clinical trials, including those for bone marrow and solid organ transplantation, autoimmune diseases, and tissue and organ repair. Here, we review the available data on culture-expanded mesenchymal stromal cells tested in renal transplantation, AKI, and CKD. We also briefly discuss the relevant issues that must be addressed to ensure rigorous assessment of the safety and efficacy of mesenchymal stromal cell therapies to allow the translation of this research into the practice of clinical nephrology.

Rapamycin reverses the senescent phenotype and improves immunoregulation of mesenchymal stem cells from MRL/lpr mice and systemic lupus erythematosus patients through inhibition of the mTOR signaling pathway

We have shown that bone marrow (BM)-derived mesenchymal stem cells (BM-MSCs) from SLE patients exhibit senescent behavior and are involved in the pathogenesis of SLE. The aim of this study was to investigate the effects of rapamycin (RAPA) on the senescences and immunoregulatory ability of MSCs of MRL/lpr mice and SLE patients and the underlying mechanisms. Cell morphology, senescence associated β-galactosidase (SA-β-gal) staining, F-actin staining were used to detect the senescence of cells. BM-MSCs and purified CD4+ T cells were co-cultured indirectly. Flow cytometry was used to inspect the proportion of regulatory T (Treg) /T helper type 17 (Th17). We used small interfering RNA (siRNA) to interfere the expression of mTOR, and detect the effects by RT-PCR, WB and immunofluorescence. Finally, 1×10⁶ of SLE BM-MSCs treated with RAPA were transplanted to cure the 8 MRL/lpr mice aged 16 weeks for 12 weeks. We demonstrated that RAPA alleviated the clinical symptoms of lupus nephritis and prolonged survival in MRL/lpr mice. RAPA reversed the senescent phenotype and improved immunoregulation of MSCs from MRL/lpr mice and SLE patients through inhibition of the mTOR signaling pathway. Marked therapeutic effects were observed in MRL/lpr mice following transplantation of BM-MSCs from SLE patients pretreated with RAPA.

Current and Future Perspectives of Stem Cell Therapy in Dermatology

Stem cells are undifferentiated cells capable of generating, sustaining, and replacing terminally differentiated cells and tissues. They can be isolated from embryonic as well as almost all adult tissues including skin, but are also generated through genetic reprogramming of differentiated cells. Preclinical and clinical research has recently tremendously improved stem cell therapy, being a promising treatment option for various diseases in which current medical therapies fail to cure, prevent progression or relieve symptoms. With the main goal of regeneration or sustained genetic correction of damaged tissue, advanced tissue-engineering techniques are especially applicable for many dermatological diseases including wound healing, genodermatoses (like the severe blistering disorder epidermolysis bullosa) and chronic (auto-)inflammatory diseases. This review summarizes general aspects as well as current and future perspectives of stem cell therapy in dermatology.

Hydrogel elasticity and microarchitecture regulate dental-derived mesenchymal stem cell-host immune system cross-talk

The host immune system (T-lymphocytes and their pro-inflammatory cytokines) has been shown to compromise bone regeneration ability of mesenchymal stem cells (MSCs). We have recently shown that hydrogel, used as an encapsulating biomaterial affects the cross-talk among host immune cells and MSCs. However, the role of hydrogel elasticity and porosity in regulation of cross-talk between dental-derived MSCs and immune cells is unclear. In this study, we demonstrate that the modulus of elasticity and porosity of the scaffold influence T-lymphocyte-dental MSC interplay by regulating the penetration of inflammatory T cells and their cytokines. Moreover, we demonstrated that alginate hydrogels with different elasticity and microporous structure can regulate the viability and determine the fate of the encapsulated MSCs through modulation of NF-kB pathway. Our in vivo data show that alginate hydrogels with smaller pores and higher elasticity could prevent pro-inflammatory cytokine-induced MSC apoptosis by down-regulating the Caspase-3- and 8- associated proapoptotic cascades, leading to higher amounts of ectopic bone regeneration. Additionally, dental-derived MSCs encapsulated in hydrogel with higher elasticity exhibited lower expression levels of NF-kB p65 and Cox-2 in vivo. Taken together, our findings demonstrate that the mechanical characteristics and microarchitecture of the microenvironment encapsulating MSCs, in addition to presence of T-lymphocytes and their pro-inflammatory cytokines, affect the fate of encapsulated dental-derived MSCs.

STATEMENT OF SIGNIFICANCE

In this study, we demonstrate that alginate hydrogel regulates the viability and the fate of the encapsulated dental-derived MSCs through modulation of NF-kB pathway. Alginate hydrogels with smaller pores and higher elasticity prevent pro-inflammatory cytokine-induced MSC apoptosis by down-regulating the Caspase-3- and 8- associated proapoptotic cascade, leading to higher amounts of ectopic bone regeneration. MSCs encapsulated in hydrogel with higher elasticity exhibited lower expression levels of NF-kB p65 and Cox-2 in vivo. These findings confirm that the fate of encapsulated MSCs are affected by the stiffness and microarchitecture of the encapsulating hydrogel biomaterial, as well as presence of T-lymphocytes/pro-inflammatory cytokines providing evidence concerning material science, stem cell biology, the molecular mechanism of dental-derived MSC-associated therapies, and the potential clinical therapeutic impact of MSCs.

Autologous Stromal Vascular Fraction in the Intravenous Treatment of End-Stage Chronic Obstructive Pulmonary Disease: A Phase I Trial of Safety and Tolerability

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a consistently progressive, ultimately fatal disease for which no treatment exists capable of either reversing or even interrupting its course. It afflicts more than 5% of the population in many countries, and it accordingly represents the third most frequent cause of death in the US, where it accounts for more than 600 billion in health care costs, morbidity, and mortality. Adipose tissue contains within its stromal compartment a high abundance of adipose stem/stromal cells (ASCs), which can be readily separated from the adipocyte population by methods which require less than 2 h of processing time and yield a concentrated cellular preparation termed the stromal vascular fraction (SVF). The SVF contains all cellular elements of fat, excluding adipocytes. Recent clinical studies have begun to explore the feasibility and safety of the local injection or intravascular delivery of SVF or more purified populations of ASCs derived by culture protocols. Several pre-clinical studies have demonstrated a remarkable ability of ASC to nearly fully ameliorate the progress of emphysema due to cigarette smoke exposure as well as other causes. However, no prior clinical studies have evaluated the safety of administration of either ASC or SVF in subjects with COPD. We hypothesized that harvest, isolation, and immediate intravenous infusion of autologous SVF would be feasible and safe in subjects with COPD; and that such an approach, if ultimately determined to be efficacious as well as safe, would provide a highly practical method for treatment of COPD.

METHODS

In this study, an initial phase I trial evaluating the early and delayed safety of SVF infusion was performed. Twelve subjects were enrolled in the study, in which adipose tissue was harvested using standard liposuction techniques, followed by SVF isolation and intravenous infusion of 150 - 300 million cells. Standardized questionnaires were administered to study feasibility as well as immediate and delayed outcomes and adverse events as primary endpoints. Secondary endpoints included subjective wellness and attitudes towards the procedure, as well as willingness to undergo the procedure a second time. The follow-up time ranged from 3 to 12 months, averaging 12 months.

RESULTS

Of the 12 subjects, only one experienced an immediate adverse event, related to bruising from the liposuction. No observed pulmonary or cardiac issues were observed as related to the procedure. There were no deaths over the 12-month study period, and none identified in the subsequent telephonic follow-up. Attitudes toward the procedure were predominantly positive, and 92% of the study subjects expressed a desire to undergo the procedure a second time.

CONCLUSIONS

This study is the first to demonstrate safety of SVF infusion in humans with serious pulmonary disease. Specifically, the use of intravenous infusion as a route to achieve pulmonary cellular targeting did not lead to clinical pulmonary compromise. The intravenous administration of SVF should be further explored as a potentially feasible and safe method for delivery leading to possible therapeutic benefit.

Adipose-Derived Stem Cells Ameliorate Experimental Murine Colitis via TSP-1-Dependent Activation of Latent TGF-β

BACKGROUND

Adipose tissue-derived stem cells (ASCs) have been investigated as therapeutic tools for a variety of autoimmune diseases, including inflammatory diseases. However, the mechanisms underlying the immunomodulatory properties of ASCs are not well understood. Here, we investigated the mechanism of regulatory T cell (Treg) induction in ASC therapy in a murine model of inflammatory bowel disease.

METHODS

Acute colitis was induced in mice using dextran sulfate sodium and ASCs administered intraperitoneally. Tregs and CD103⁺ dendritic cells were analyzed in the mesenteric lymph nodes (MLNs), spleen, and colonic lamina propria (CLP). Activation of latent TGF-β by ASCs was analyzed in vitro using ELISA. siRNA technology was used to create ASCs in which TSP-1 or integrinαv was knocked down in order to investigate the involvement of these proteins in the activation of latent TGF-β. In addition, TSP-1-knockdown ASCs were administered to mice with colitis to assess their clinical efficacy in vivo.

RESULTS

Systemic administration of ASCs significantly lessened the clinical and histopathological severity of colitis. ASCs were distributed throughout the lymphatic system in the MLNs and spleen. Tregs were increased in the MLNs and CLP, but CD103⁺ dendritic cells were not significantly altered. The ASCs activated latent TGF-β. TSP-1 knockdown impaired TGF-β activation in vitro and abrogated the therapeutic effects of the ASCs in vivo. Furthermore, Tregs were not increased in the MLNs and CLP from mice treated with TSP-1-knockdown ASCs.

CONCLUSIONS

These results demonstrate that ASCs induce Tregs by activating latent TGF-β via TSP-1, independent of CD103⁺ dendritic cell induction.

Interactions between mesenchymal stem cells and the immune system

In addition to being multi-potent, mesenchymal stem cells (MSCs) possess immunomodulatory functions that have been investigated as potential treatments in various immune disorders. MSCs can robustly interact with cells of the innate and adaptive immune systems, either through direct cell-cell contact or through their secretome. In this review, we discuss current findings regarding the interplay between MSCs and different immune cell subsets. We also draw attention to the mechanisms involved.

The potential role of adult stem cells in the management of the rheumatic diseases

Adult stem cells are considered as appealing therapeutic candidates for inflammatory and degenerative musculoskeletal diseases. A large body of preclinical research has contributed to describing their immune-modulating properties and regenerative potential. Additionally, increasing evidence suggests that stem cell differentiation and function are disrupted in the pathogenesis of rheumatic diseases. Clinical studies have been limited, for the most part, to the application of adult stem cell-based treatments on small numbers of patients or as a 'salvage' therapy in life-threatening disease cases. Nevertheless, these preliminary studies indicate that adult stem cells are promising tools for the long-term treatment of rheumatic diseases. This review highlights recent knowledge acquired in the fields of hematopoietic and mesenchymal stem cell therapy for the management of systemic sclerosis (SSc), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and osteoarthritis (OA) and the potential mechanisms mediating their function.

Human iPSC-MSC-Derived Xenografts Modulate Immune Responses by Inhibiting the Cleavage of Caspases

Mesenchymal stem cells (MSCs) negatively modulate immune properties. Induced pluripotent stem cells (iPSCs)-derived MSCs are alternative source of MSCs. However, the effects of iPSC-MSCs on T cells phenotypes in vivo remain unclear. We established an iPSC-MSC-transplanted host versus graft reaction mouse model using subcapsular kidney injection. Th1, Th2, regulatory T cells (Treg), and Th17 phenotypes and their cytokines were investigated in vivo and in vitro. The role of caspases and the soluble factors involved in the effects of MSCs were examined. We found that iPSC-MSC grafts led to more cell survival and less infiltration of inflammatory cells in mice. iPSC-MSC transplantation inhibited T cell proliferation, decreased Th1 and Th2 phenotypes and cytokines, upregulated Th17 and Treg subsets. Moreover, iPSC-MSCs inhibited the cleavage of caspases 3 and 8 and inhibition of caspases downregulated Th1, Th2 responses and upregulated Th17, Treg responses. Soluble factors were determined using protein array and TGF-β1/2/3, IL-10, and MCP-1 were found to be highly expressed in iPSC-MSCs. The administration of the soluble factors decreased Th1/2 response, upregulated Treg response and inhibited the cleavage of caspases. Our results demonstrate that iPSC-MSCs regulate T cell responses as a result of a combined action of the above soluble factors secreted by iPSC-MSCs. These factors suppress T cell responses by inhibiting the cleavage of caspases. These data provide a novel immunomodulatory mechanism for the underlying iPSC-MSC-based immunomodulatory effects on T cell responses. Stem Cells 2017;35:1719-1732.

Therapeutic Development of Mesenchymal Stem Cells or Their Extracellular Vesicles to Inhibit Autoimmune-Mediated Inflammatory Processes in Systemic Lupus Erythematosus

Since being discovered over half a century ago, mesenchymal stem cells (MSCs) have been investigated extensively to characterize their cellular and physiological influences. MSCs have been shown to possess immunosuppressive capacity through inhibiting lymphocyte activation/proliferation and proinflammatory cytokine secretion while simultaneously demonstrating limited allogenic reactivity, which subsequently led to the evaluation of therapeutic feasibility to treat inflammatory diseases. Although regulatory constraints have restricted MSC development pharmacologically, limited clinical studies have shown encouraging results using MSC infusions to treat systemic lupus erythematosus (SLE); but, more trials will have to be performed to conclusively determine the clinical efficacy of MSCs to treat SLE. Moreover, there are some data to suggest that MSCs possess tumorigenic potential and that the immunosuppressive influence can be dramatically affected by both donor variability and ex vivo expansion. Given that recent studies have found that the immunosuppressive effects of MSCs are a result, at least in part, to extracellular vesicle (EV) secretion, the use of MSC-derived EVs has been suggested as a cell-free therapeutic alternative. Despite the positive data observed using EVs isolated from human MSCs to suppress inflammatory responses in vitro and in inhibiting autoimmune disease pathogenesis in preclinical work, there are no studies to date examining EVs from MSCs to treat SLE in humans or animal models. Considering that EVs are not subject to the strict regulatory constraints of stem cell-based pharmacological development and are more readily standardized with regard to industrial-scale production and storage, this review outlines the anti-inflammatory biology of MSCs and the scientific evidence supporting the potential use of EVs derived from human MSCs to treat patients with SLE.

Mesenchymal stromal cells and autoimmunity

Mesenchymal stromal cells (MSCs) are committed progenitors of mesodermal origin that are found virtually in every organ and exhibit multilineage differentiation into osteocytes, adipocytes and chondrocytes. MSCs also mediate a wide spectrum of immunoregulatory activities that usually dampen innate and adaptive immune responses. These features have attracted interest in the perspective of developing novel cell therapies for autoimmune disease. However, depending on the microenvironmental conditions, MSCs may show a plastic behavior and switch to an immunostimulatory phenotype. After thorough characterization of the effects of MSCs on the immune system, MSC cell therapy has been tested in animal models of autoimmunity using different cell sources, protocols of in vitro expansion and routes and schedules of administration. The pre-clinical results have been encouraging in some models [e.g. Crohn's disease (CD), multiple sclerosis] and heterogeneous in others (e.g. graft-versus-host disease, systemic lupus erythematosus, rheumatoid arthritis). Clinical trials have been carried out and many are ongoing. As discussed, the results obtained are too preliminary to draw any conclusion, with the only exception of topical administration of MSCs in CD that has proven efficacious. The mechanism of action of infused MSCs is still under investigation, but the apparent paradox of a therapeutic effect achieved in spite of the very low number of cells reaching the target organ has been solved by the finding that MSC-derived extracellular vesicles (EVs) closely mimic the therapeutic activity of MSCs in pre-clinical models. These issues are critically discussed in view of the potential clinical use of MSC-derived EVs.

Immunomodulation by Mesenchymal Stromal Cells and Their Clinical Applications

Mesenchymal stromal cells (MSCs) are multipotent progenitor cells that can be isolated and expanded from various sources. MSCs modulate the function of immune cells, including T and B lymphocytes, dendritic cells, and natural killer cells. An understanding of the interaction between MSCs and the inflammatory microenvironment will provide critical information in revealing the precise in vivo mechanisms involved in MSCs-mediated therapeutic effects, and for designing more practical protocols for the clinical use of these cells. In this review we describe the current knowledge of the unique biological properties of MSCs, the immunosuppressive effects on immune-competent cells and the paracrine role of soluble factors. A summary of the participation of MSCs in preclinical and clinical studies in treating autoimmune diseases and other diseases is described. We also discuss the current challenges of their use and their potential roles in cell therapies.

Mesenchymal stem cell transplantation in tight-skin mice identifies miR-151-5p as a therapeutic target for systemic sclerosis

Systemic sclerosis (SSc), an autoimmune disease, may cause significant osteopenia due to activation of the IL4Rα/mTOR pathway. Mesenchymal stem cell transplantation (MSCT) can ameliorate immune disorders in SSc via inducing immune tolerance. However, it is unknown whether MSCT rescues osteopenia phenotype in SSc. Here we show that MSCT can effectively ameliorate osteopenia in SSc mice by rescuing impaired lineage differentiation of the recipient bone marrow MSCs. Mechanistically, we show that donor MSCs transfer miR-151-5p to the recipient bone marrow MSCs in SSc mice to inhibit IL4Rα expression, thus downregulating mTOR pathway activation to enhance osteogenic differentiation and reduce adipogenic differentiation. Moreover, systemic delivery of miR-151-5p is capable of rescuing osteopenia, impaired bone marrow MSCs, tight skin, and immune disorders in SSc mice, suggesting that miR-151-5p may be a specific target for SSc treatment. Our finding identifies a previously unrecognized role of MSCT in transferring miRNAs to recipient stem cells to ameliorate osteopenia via rescuing a non-coding RNA pathway.

Recipient Glycemic Micro-environments Govern Therapeutic Effects of Mesenchymal Stem Cell Infusion on Osteopenia

Therapeutic effects of mesenchymal stem cell (MSC) infusion have been revealed in various human disorders, but impacts of diseased micro-environments are only beginning to be noticed. Donor diabetic hyperglycemia is reported to impair therapeutic efficacy of stem cells. However, whether recipient diabetic condition also affects MSC-mediated therapy is unknown. We and others have previously shown that MSC infusion could cure osteopenia, particularly in ovariectomized (OVX) mice. Here, we discovered impaired MSC therapeutic effects on osteopenia in recipient type 1 diabetes (T1D). Through intensive glycemic control by daily insulin treatments, therapeutic effects of MSCs on osteopenia were maintained. Interestingly, by only transiently restoration of recipient euglycemia using single insulin injection, MSC infusion could also rescue T1D-induced osteopenia. Conversely, under recipient hyperglycemia induced by glucose injection in OVX mice, MSC-mediated therapeutic effects on osteopenia were diminished. Mechanistically, recipient hyperglycemic micro-environments reduce anti-inflammatory capacity of MSCs in osteoporotic therapy through suppressing MSC interaction with T cells via the Adenosine monophosphate-activated protein kinase (AMPK) pathway. We further revealed in diabetic micro-environments, double infusion of MSCs ameliorated osteopenia by anti-inflammation, attributed to the first transplanted MSCs which normalized the recipient glucose homeostasis. Collectively, our findings uncover a previously unrecognized role of recipient glycemic conditions controlling MSC-mediated therapy, and unravel that fulfillment of potent therapeutic effects of MSCs requires tight control of recipient micro-environments.

JAK-STAT signaling mediates the senescence of bone marrow-mesenchymal stem cells from systemic lupus erythematosus patients

Previous studies have revealed that bone marrow-mesenchymal stem cells (BM-MSCs) from systemic lupus erythematosus (SLE) patients exhibited early signs of senescence, which may participate in the development of SLE. However, the molecular mechanisms about this phenomenon have not been fully elucidated. In the current study, we aimed to investigate whether Janus kinase (JAK)-signaling transducers and activators of transcription (STAT) signaling mediated the senescence of BM-MSCs from SLE patients. Twelve female SLE patients and healthy subjects were enrolled in the study. All BM-MSCs were isolated by density gradient centrifugation. Western blot analysis was used to test the expression of JAK-STAT signaling molecules. We observed the activity of β-gal of cells, the changes of cytoskeletal structure by F-actin staining, and the distribution of cell cycle by flow cytometry. BM-MSCs from SLE patients showed prominent features of senescence, and abnormal activation of JAK-STAT signaling transduction, high level of phosphorylated JAK2, and STAT3. After stimulation of IFN-γ in normal MSCs, JAK-STAT signaling was activated. The cell volume and the number of senescence-associated β-galactosidase (SA-β-gal) positive in SLE BM-MSCs were increased. The organization of cytoskeleton was nearly disordered. The rate of cell proliferation was decreased. AG490, the inhibitor of JAK2, and knockdown of STAT3 in BM-MSCs, could significantly reverse the senescence. In summary, our study indicated that JAK-STAT signaling pathway may play a critical role in the senescence of SLE BM-MSCs.

Mesenchymal Stem Cell Therapy for Inflammatory Skin Diseases: Clinical Potential and Mode of Action

Inflammatory skin disorders that cause serious deterioration of the quality of life have become one of the major public concerns. Despite their significance, there is no fundamental cure to date. Mesenchymal stem cells (MSCs) possess unique immunomodulatory properties which make them a promising tool for the treatment of various inflammatory diseases. Our recent preclinical and clinical studies have shown that MSCs can be successfully used for the treatment of atopic dermatitis (AD), one of the major inflammatory skin diseases. This observation along with similar reports from other groups revealed the efficacy and underlying mechanisms of MSCs in inflammatory dermatosis. In addition, it has been proposed that cell priming or gene transduction can be novel strategies for the development of next-generation high-efficacy MSCs for treating inflammatory skin diseases. We discuss here existing evidence that demonstrates the regulatory properties of MSCs on immune responses under inflammatory conditions.

Human Umbilical Cord Mesenchymal Stem Cells Inhibit T Follicular Helper Cell Expansion Through the Activation of iNOS in Lupus-Prone B6.MRL-Faslpr Mice

The aberrant generation or activation of T follicular helper (Tfh) cells contributes to the pathogenesis of systemic lupus erythematosus (SLE), yet little is known about how these cells are regulated. In this study, we demonstrated that the frequency of Tfh cells was increased in lupus-prone B6.MRL-Faslpr (B6.lpr) mice and positively correlated to plasma cell proportions and serum total IgG as well as anti-dsDNA antibody levels. Transplantation of mesenchymal stem cells derived from Wharton's jelly of human umbilical cords (hUC-MSCs) ameliorated lupus symptoms in B6.lpr mice, along with decreased percentages of Tfh cells. In vitro studies showed that the differentiation and proliferation of Tfh cells were markedly suppressed by hUC-MSCs. The production of inducible nitric oxide synthase (iNOS) was dramatically upregulated in hUC-MSCs when cocultured with CD4+ T cells directly, while adding the specific inhibitor of iNOS into the coculture system significantly reversed the inhibitory effect of hUC-MSCs on Tfh cell generation. Interestingly, the efficacy of hUC-MSCs in inhibiting Tfh cells was impaired in the Transwell system, with the reduction of iNOS in both mRNA and protein levels. Taken together, our findings suggest that hUC-MSCs could effectively inhibit Tfh cell expansion through the activation of iNOS in lupus-prone B6.lpr mice, which is highly dependent on cell-to-cell contacts.

The Future of Atopic Dermatitis Treatment

In recent years, there has been a growing movement towards the use of targeted therapies in treating of atopic dermatitis (AD), parallel to that which has occurred in psoriasis. Among the systemic medications being studied are subcutaneous or intravenously administered biologic drugs targeting specific molecules such as IL4, IL13, IL17, and IgE. Non-biologic oral therapies are also being developed for AD and include small molecule drugs targeting phosphodiesterase type IV (PDE4) inhibition or Janus Kinase (JAK) inhibition. Numerous topical formulations are also being studied, with some formulations that are novel therapies that act as topical biologic or small molecule agents with mechanisms of action similar to systemic treatments. Others are being developed as skin barrier repair therapies for reduction of AD symptoms. This chapter will discuss new advances in AD treatment from medications in the initial stages of development to those nearing FDA approval.

Stem Cell Therapy in the Treatment of Rheumatic Diseases and Application in the Treatment of Systemic Lupus Erythematosus

Current systemic therapies help to improve the symptoms and quality of life for patients with severe life-threatening rheumatic diseases but provide no curative treatment. For the past two decades, preclinical and clinical studies of stem cell transplantation (SCT) have demonstrated tremendous therapeutic potential for patients with autoimmune rheumatic diseases. Herein, the current advances on stem cell therapies, both in animal models and clinical studies, are discussed, with particular attention on systemic lupus erythematosus (SLE). Despite extensive research and promising data, our knowledge on mechanisms of action for SCT, its administration route and timing, the optimal dose of cells, the cells’ fate and distribution in vivo, and the safety and efficacy of the treatments remains limited. Further research on stem cell biology is required to ensure that therapeutic safety and efficacy, as observed in animal models, can be successfully translated in clinical trials. Current understanding, limitations, and future directions for SCT with respect to rheumatic diseases are also discussed.

Adipose-Derived Cell Transplantation in Systemic Sclerosis: State of the Art and Future Perspectives

Systemic sclerosis (SSc) is one of the most complex connective tissue diseases. Although significant progress in the knowledge of pathogenic mechanisms and timely diagnosis, therapeutic options remain limited. The attempt to find new treatments for SSc has led researchers to investigate the potential of cellular therapies using autologous and allogeneic stem cells. Multipotent mesenchymal stromal cells (MSCs) are considered an attractive candidate for cell-based therapies. MSCs comprise a heterogeneous population of cells with multilineage differentiation potential that are preferentially able to home to the sites of damage, and secrete various cytokines and growth factors that can have immunomodulatory, angiogenic, anti-inflammatory and anti-apoptotic effects. MSCs from bone-marrow have been first extensively characterized. Adipose tissue represents an additional abundant and accessible source of stem cells. Compared with BM-MSCs, adipose-derived stromal/stem cells (ASCs) offer several advantages, including ease of isolation, less donor morbidity, relative abundance, and rapidity of expansion. For all these reasons, at present ASCs are one of the most attractive and promising sources of adult stem cells for cell therapy, finding a field of application in the treatment of SSc, too. This review will focus on the current applications and possible future perspectives of adipose tissue-cell therapies in SSc.

The Current Status of Stem-Cell Therapy in Erectile Dysfunction: A Review

Stem cells are undifferentiated cells that are capable of renewal and repair of tissue due to their capacity for division and differentiation. The purpose of this review is to describe recent advances in the use of stem cell (SC) therapy for male erectile dysfunction (ED). We performed a MEDLINE database search of all relevant articles regarding the use of SCs for ED. We present a concise summary of the scientific principles behind the usage of SC for ED. We discuss the different types of SCs, delivery methods, current pre-clinical literature, and published clinical trials. Four clinical trials employing SC for ED have been published. These articles are summarized in this review. All four report improvements in ED after SC therapy. SC therapy remains under investigation for the treatment of ED. It is reassuring that clinical trials thus far have reported positive effects on erectile function and few adverse events. Safety and methodical concerns about SC acquisition, preparation and delivery remain and require continued investigation prior to wide-spread application of these methods.

Transplantation of human umbilical cord mesenchymal stem cells in cochlea to repair sensorineural hearing

To examine if transplantation of human umbilical cord mesenchymal stem cells (UMSC) into cochlea can be used to repair sensorineural hearing. Here we transplanted the fifth and sixth generations of UMSCs through the subarachnoid cavity of congenital deaf albino pigs. Auditory brainstem responses (ABR) were measured before and after UMSC transplantation. Cochlear samples were collected at 2 hrs, 3 days, 1, 2, 3, 4 and 8 weeks after transplantation. Immunohistochemistry was used to detect the proliferated cell nuclear antigen (PCNA). The UMSCs were found in different regions of the cochlea, including the stria vascularis, the basal membrane and the spiral ganglions, 3 days to 4 weeks after the transplantation. UMSCs and their DNA were found also in the areas of the brain, the heart, the liver, the kidney and the lung. ABR tests displayed a new waveform in the congenital deaf albino pigs after the UMSCs transplantation. We conclude that human UMSCs injected into the subarachnoid space can migrate into the inner ear, the central nervous system and the periphery organs. The presence of UMSCs in the cochlea maybe associated with changes of ABR waveforms in the congenital deaf albino pigs.

C1q as an autocrine and paracrine regulator of cellular functions

Most of the complement proteins in circulation are, by and large, synthesized in the liver. However data accumulated over the past several decades provide incontrovertible evidence that some if not most of the individual complement proteins are also synthesized extrahepatically by activated as well as non-activated cells. The question that is finally being addressed by various investigators is: are the locally synthesized proteins solely responsible for the myriad of biological functions in situ without the contribution of systemic complement? The answer is probably "yes". Among the proteins that are synthesized locally, C1q takes center stage for several reasons. First, it is synthesized predominantly by potent antigen presenting cells such as monocytes, macrophages and dendritic cells (DCs), which by itself is a clue that it plays an important role in antigen presentation and/or DC maturation. Second, it is transiently anchored on the cell surface via a transmembrane domain located in its A chain before it is cleaved off and released into the pericellular milieu. The membrane-associated C1q in turn, is able to sense danger patterns via its versatile antigen-capturing globular head domains. More importantly, locally synthesized C1q has been shown to induce a plethora of biological functions through the induction of immunomodulatory molecules by an autocrine- or paracrine- mediated signaling in a manner that mimics those of TNFα. These include recognition of pathogen- and danger- associated molecular patterns, phagocytosis, angiogenesis, apoptosis and induction of cytokines or chemokines that are important in modulating the inflammatory response. The functional convergence between C1q and TNFα in turn is attributed to their shared genetic ancestry. In this paper, we will infer to the aforementioned "local-synthesis-for-local function" paradigm using as an example, the role played by locally synthesized C1q in autoimmunity in general and in systemic lupus erythematosus in particular.

Preconditioning of Human Mesenchymal Stem Cells to Enhance Their Regulation of the Immune Response

Mesenchymal stem cells (MSCs) have attracted the attention of researchers and clinicians for their ability to differentiate into a number of cell types, participate in tissue regeneration, and repair the damaged tissues by producing various growth factors and cytokines, as well as their unique immunoprivilege in alloreactive hosts. The immunomodulatory functions of exogenous MSCs have been widely investigated in immune-mediated inflammatory diseases and transplantation research. However, a harsh environment at the site of tissue injury/inflammation with insufficient oxygen supply, abundance of reactive oxygen species, and presence of other harmful molecules that damage the adoptively transferred cells collectively lead to low survival and engraftment of the transferred cells. Preconditioning of MSCs ex vivo by hypoxia, inflammatory stimulus, or other factors/conditions prior to their use in therapy is an adaptive strategy that prepares MSCs to survive in the harsh environment and to enhance their regulatory function of the local immune responses. This review focuses on a number of approaches in preconditioning human MSCs with the goal of augmenting their capacity to regulate both innate and adaptive immune responses.

Preconditioning of Human Mesenchymal Stem Cells to Enhance Their Regulation of the Immune Response

Mesenchymal stem cells (MSCs) have attracted the attention of researchers and clinicians for their ability to differentiate into a number of cell types, participate in tissue regeneration, and repair the damaged tissues by producing various growth factors and cytokines, as well as their unique immunoprivilege in alloreactive hosts. The immunomodulatory functions of exogenous MSCs have been widely investigated in immune-mediated inflammatory diseases and transplantation research. However, a harsh environment at the site of tissue injury/inflammation with insufficient oxygen supply, abundance of reactive oxygen species, and presence of other harmful molecules that damage the adoptively transferred cells collectively lead to low survival and engraftment of the transferred cells. Preconditioning of MSCs ex vivo by hypoxia, inflammatory stimulus, or other factors/conditions prior to their use in therapy is an adaptive strategy that prepares MSCs to survive in the harsh environment and to enhance their regulatory function of the local immune responses. This review focuses on a number of approaches in preconditioning human MSCs with the goal of augmenting their capacity to regulate both innate and adaptive immune responses.