Role of mesenchymal stem cells in reestablishing immunologic tolerance in autoimmune rheumatic diseases

Efficacy and safety of culture-expanded mesenchymal stromal cell therapy in the treatment of 4 types of inflammatory arthritis: A systematic review and meta-analysis of 36 randomized controlled trials

OBJECTIVE

This study aims to assess the effectiveness and safety of mesenchymal stem cell (MSC) transplantation in the treatment of inflammatory arthritis.

METHODS

Two researchers conducted a comprehensive search of Chinese and English databases from their inception until July 2023. The literature screening and data extraction were then performed. Statistical analysis was carried out using RevMan 5.4 software.

RESULTS

A total of 36 relevant RCTs, involving 2,076 participants, were ultimately included in this study. These RCTs encompassed four types of inflammatory arthritis, namely rheumatoid arthritis (RA), osteoarthritis (OA), ankylosing spondylitis (AS), and systemic sclerosis (SSc). The results demonstrated that MSC therapy exhibited improvements in the Visual Analog Scale (VAS) for pain in OA patients (bone marrow: SMD=-0.95, 95 % CI: -1.55 to -0.36, P = 0.002; umbilical cord: SMD=-2.03, 95 % CI: -2.99 to -1.07, P < 0.0001; adipose tissue: SMD=-1.26, 95 % CI: -1.99 to -0.52, P = 0.0009). Specifically, MSCs sourced from adipose tissue showed enhancements in Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain (P = 0.0001), WOMAC physical function (P = 0.001), and total WOMAC scores (P = 0.0003). As for MSC therapy in RA, AS, and SSc, the current systematic review suggests a potential therapeutic effect of MSCs on these inflammatory arthritic conditions. Safety assessments indicated that MSC therapy did not increase the incidence of adverse events.

CONCLUSION

MSCs have the potential to alleviate joint pain and improve joint function in patients with inflammatory arthritis. Moreover, MSC therapy appears to be relatively safe and could be considered as a viable alternative treatment option for inflammatory arthritis.

A State-of-the-Art Review on the Recent Advances of Mesenchymal Stem Cell Therapeutic Application in Systematic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with an unknown etiology that has widespread clinical and immunological manifestations. Despite the increase in knowledge about the pathogenesis process and the increase in treatment options, however, the treatments fail in half of the cases. Therefore, there is still a need for research on new therapies. Mesenchymal stem cells (MSCs) are powerful regulators of the immune system and can reduce the symptoms of systemic lupus erythematosus. This study aimed to review the mechanisms of immune system modulation by MSCs and the role of these cells in the treatment of SLE. MSCs suppress T lymphocytes through various mechanisms, including the production of transforming growth factor-beta (TGF-B), prostaglandin E2 (PGE2), nitric oxide (NO), and indolamine 2 and 3-oxygenase (IDO). In addition, MSCs inhibit the production of their autoantibodies by inhibiting the differentiation of lymphocytes. The production of autoantibodies against nuclear antigens is an important feature of SLE. On the other hand, MSCs inhibit antigen delivery by antigen-presenting cells (APCs) to T lymphocytes. Studies in animal models have shown the effectiveness of these cells in treating SLE. However, few studies have been performed on the effectiveness of this treatment in humans. It can be expected that new treatment strategies for SLE will be introduced in the future, given the promising results of MSCs application.

Long-term passages of human clonal mesenchymal stromal cells can alleviate the disease in the rat model of collagen-induced arthritis resembling early passages of different heterogeneous cells

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease of unknown cause. The interaction of immune system cells and the secretion of inflammatory cytokines with synovial cells leads to severe inflammation in the affected joints. Currently, medications, including non-steroidal anti-inflammatory drugs, glucocorticoids, and more recently, disease-modifying anti-rheumatic drugs, are used to reduce inflammation. However, long-term use of these drugs causes adverse effects or resistance in a considerable number of RA patients. Recent findings revealed the safety and efficacy of mesenchymal stromal cells (MSCs)-based therapies both in RA animal models and clinical trials. Here, the beneficial effects of bone marrow-derived heterogeneous MSCs (BM-hMSCs) and Wharton jelly-derived MSCs (WJ-MSCs) at early passages were compared to BM-derived clonal MSCs (BM-cMSCs) at high passage number on a rat model of collagen-induced arthritis. Results showed that systemic delivery of MSCs significantly reversed adverse changes in body weight, paw swelling, and arthritis score in all MSC-treated groups. Radiological images and histological evaluation demonstrated the therapeutic effects of MSCs. There was a decrease in serum level of anti-collagen type II immunoglobulin G and the inflammatory cytokines interleukin (IL)-1β, IL-6, IL-17, and tumor necrosis factor-α in all MSC-treated groups. In contrast, an increase in inhibitory cytokines transforming growth factor-β and IL-10 was seen. Notably, the long-term passages of BM-cMSCs could alleviate RA symptoms similar to the early passages of WJ-MSCs and BM-hMSCs. The importance of BM-cMSCs is the potential to establish cell banks with billions of cells derived from a single donor that could be a competitive cell-based therapy to treat RA.

Role of cryopreserved multipotent mesenchymal stromal cells in modulation of some indices of cell immunity in adjuvant arthritis

Inroduction

The results of experimental and clinical studies in recent years indicate that the transplantation of multipotent mesenchymal stromal cells (MMSCs) is a possible approach for the "restoration" of the immune system of patients with autoimmune diseases, in particular, rheumatoid arthritis. However, the strength and duration of the effect vary greatly, which indicates incomplete correction of the tested parameters, thereby opening up the prospect of improving this method of treatment by choosing dose-time parameters and methods of their administration. The aim of this research was to determine the indices of cellular immunity in animals with adjuvant arthritis and therapy with cryopreserved MMSCs derived from adipose and cartilage tissues.

Material and methods

Adjuvant arthritis in male rats was modeled by subplantar administration of Freund's complete adjuvant. On day 7 of modeling, experimental animals were administered with saline (control group) or cryopreserved MMSCs from adipose or cartilaginous tissue locally or generalized. On day 28 after therapy the body weight, spleen index and cellularity, and content of CD3+, CD4+, CD8+, CD4+CD25+ cells in the spleen were determined.

Results

In the control group of animals, the inflammation was pronounced, as evidenced by a significant increase in the studied parameters throughout the observation period. The use of cryopreserved MMSCs from adipose and cartilaginous tissues led to the restoration of T regulatory cells (Treg) on day 28. Generalized administration of cells had a more pronounced therapeutic effect compared to the animals with local administration. These data can be used to justify and develop a therapeutic approach to rheumatoid arthritis in clinical practice.

Conclusions

Cell therapy with cryopreserved MMSCs from investigated sources provided by both local and generalized administration to animals with adjuvant arthritis has a correcting effect on the cellular immunity.

Stromal-vascular fraction of adipose tissue as an alternative source of cellular material for regenerative medicine

Adipose tissue is the most convenient source of cellular material for regenerative medicine as it can be obtained in significant quantities via cosmetic liposuction, lipoaspiration of subcutaneous fat or by excision of fat deposits. Adipose tissue consists of adipocytes and cells, which are the part of the stromal-vascular fraction (SVF). Different cell populations can be isolated from SVF, among which the population of adipose tissue stem cells (adipose-derived stem cells, ADSC) is especially important for regenerative medicine. SVF can be obtained relatively easily from adipose tissue (adipose tissue is an alternative to bone marrow in terms of being a source of stem cells) and used to treat various pathologies. Recent studies show that SVF not only has a therapeutic effect similar to that of ADSC, but in some cases is even more effective. The article provides the analysis of the main methods of SVF obtainment, characteristics of SVF cellular composition, its potential for use in clinical medicine and its main advantages over other sources of cellular material, including­ ADSC cultured in vitro, for regenerative medicine. Keywords: adipocytes, adipose-derived stem cells, regenerative medicine, stromal-vascular fraction

CD73 immune checkpoint defines regulatory NK cells within the tumor microenvironment

High levels of ecto-5'-nucleotidase (CD73) have been implicated in immune suppression and tumor progression, and have also been observed in cancer patients who progress on anti-PD-1 immunotherapy. Although regulatory T cells can express CD73 and inhibit T cell responses via the production of adenosine, less is known about CD73 expression in other immune cell populations. We found that tumor-infiltrating NK cells upregulate CD73 expression and the frequency of these CD73-positive NK cells correlated with larger tumor size in breast cancer patients. In addition, the expression of multiple alternative immune checkpoint receptors including LAG-3, VISTA, PD-1, and PD-L1 was significantly higher in CD73-positive NK cells than in CD73-negative NK cells. Mechanistically, NK cells transport CD73 in intracellular vesicles to the cell surface and the extracellular space via actin polymerization-dependent exocytosis upon engagement of 4-1BBL on tumor cells. These CD73-positive NK cells undergo transcriptional reprogramming and upregulate IL-10 production via STAT3 transcriptional activity, suppressing CD4-positive T cell proliferation and IFN-γ production. Taken together, our results support the notion that tumors can hijack NK cells as a means to escape immunity and that CD73 expression defines an inducible population of NK cells with immunoregulatory properties within the tumor microenvironment.

The immunomodulatory effects of mesenchymal stromal cell-based therapy in human and animal models of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune inflammatory disease with no absolute cure. Although the exact etiopathogenesis of SLE is still enigmatic, it has been well demonstrated that a combination of genetic predisposition and environmental factors trigger a disturbance in immune responses and thereby participate in the development of this condition. Almost all available therapeutic strategies in SLE are primarily based on the administration of immunosuppressive drugs and are not curative. Mesenchymal stromal cells (MSCs) are a subset of non-hematopoietic adult stem cells that can be isolated from many adult tissues and are increasingly recognized as immune response modulating agents. MSC-mediated inhibition of immune responses is a complex mechanism that involves almost every aspect of the immune response. MSCs suppress the maturation of antigen-presenting cells (DC and MQ), proliferation of T cells (Th1, T17, and Th2), proliferation and immunoglobulin production of B cells, the cytotoxic activity of CTL and NK cells in addition to increasing regulatory cytokines (TGF-β and IL10), and decreasing inflammatory cytokines (IL17, INF-ϒ, TNF-α, and IL12) levels. MSCs have shown encouraging results in the treatment of several autoimmune diseases, in particular SLE. This report aims to review the beneficial and therapeutic properties of MSCs; it also focuses on the results of animal model studies, preclinical studies, and clinical trials of MSC therapy in SLE from the immunoregulatory aspect.

The Effect of Intra-articular versus Intravenous Injection of Mesenchymal Stem Cells on Experimentally-Induced Knee Joint Osteoarthritis

Background

Osteoarthritis (OA) is a chronic degenerative debilitating disease, primarily affects joints, particularly weight-bearing areas. The surface layer of the articular cartilage breaks down and wears away leading to rubbing of bones, pain, swelling, and joint stiffness.

Aim and Objectives

This study investigates the possible therapeutic effects of intra-articular versus intravenous injection of umbilical cord blood mesenchymal stem cells (UCB-MSCs) against mono-iodoacetate-induced OA of the knee joints in male albino rats, using histological and immunohistochemical techniques.

Materials and Methods

Thirty male adult albino rats were randomized into five groups as follows: Group (I) and (II): Served as control. Group (III): Osteoarthritic group. Group IV: Osteoarthritic and intraarticularly-injected MSCs. Group V: Osteoarthritic and intravenously-injected MSCs. Animals were sacrificed 1 month after stem cell injection, the right knee was prepared for histological techniques (Hematoxylin and Eosin and Toluidine blue stains) and immunohistochemical technique (Bax stain). Prussian blue stain was used to assess homing of MSCs in Groups IV and V.

Results

Knee joint surface was irregular, fissured, and fragmented in Group III. In Groups IV and V, affected area was filled with newly formed tissue. Toluidine blue showed a decrease in matrix staining in Group III compared to both control and MSCs-treated groups. Chondrocytes in Group III showed strong Bax immunoreactivity and this reaction decreased in Group IV and V; however, Group V immunoreactivity was more than Group IV. Prussian blue stain showed labeled UCB-MSCs in many chondrocytes in Group IV and few chondrocytes in Group V.

Conclusion

Intraarticularly-injected UCB-MSCs showed better healing of knee OA than intravenously-injected UCB-MSCs.

Mesenchymal Stem Cells Extract (MSCsE)-Based Therapy Alleviates Xerostomia and Keratoconjunctivitis Sicca in Sjogren's Syndrome-Like Disease

Sjogren’s syndrome (SS) is an autoimmune disease that manifests primarily in salivary and lacrimal glands leading to dry mouth and eyes. Unfortunately, there is no cure for SS due to its complex etiopathogenesis. Mesenchymal stem cells (MSCs) were successfully tested for SS, but some risks and limitations remained for their clinical use. This study combined cell- and biologic-based therapies by utilizing the MSCs extract (MSCsE) to treat SS-like disease in NOD mice. We found that MSCsE and MSCs therapies were successful and comparable in preserving salivary and lacrimal glands function in NOD mice when compared to control group. Cells positive for AQP5, AQP4, α-SMA, CK5, and c-Kit were preserved. Gene expression of AQP5, EGF, FGF2, BMP7, LYZ1 and IL-10 were upregulated, and downregulated for TNF-α, TGF-β1, MMP2, CASP3, and IL-1β. The proliferation rate of the glands and serum levels of EGF were also higher. Cornea integrity and epithelial thickness were maintained due to tear flow rate preservation. Peripheral tolerance was re-established, as indicated by lower lymphocytic infiltration and anti-SS-A antibodies, less BAFF secretion, higher serum IL-10 levels and FoxP3⁺ T_reg cells, and selective inhibition of B220⁺ B cells. These promising results opened new venues for a safer and more convenient combined biologic- and cell-based therapy.

Immunomodulatory effect of human umbilical cord mesenchymal stem cells on T lymphocytes in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease which is lack of effective therapies. Abnormal activation, proliferation, and differentiation of T lymphocytes are closely related to RA. Mesenchymal stem cells (MSCs) can be used for RA treatment due to their immunoregulatory effects. However, the specific molecular mechanisms have not been fully elucidated and the therapeutic effect has been inconsistent. This study investigated the immunomodulatory effect of human umbilical cord MSCs (hUCMSCs) on T lymphocytes in collagen-induced arthritis (CIA) rats and RA patients to clarify the possible mechanism of hUCMSCs in RA treatment. The effects of hUCMSCs on arthritis index, radiological and synovial pathological changes, T lymphocyte proliferation and apoptosis, RORγt and Foxp3 expression, Th17 and Treg cell ratios, and IL-17 and TGF-β levels were assessed in CIA rats. Further, we verified the effect of hUCMSCs in RA patients, and compared the effect of hUCMSCs with that of hUCMSC derived extracellular vesicles (EVs). The results showed that hUCMSCs inhibited the proliferation and promoted apoptosis in T lymphocytes, downregulated RORγt mRNA and protein expression, decreased Th17 cell ratio, upregulated Foxp3 mRNA and protein expression, and increased Treg cell ratio in the spleen. Furthermore, they downregulated RORγt and Foxp3 expression in the joints, and inhibited IL-17 and promoted TGF-β expression in the serum, thereby improving arthritis, delaying radiological progression, and inhibiting synovial hyperplasia in CIA rats. In vitro the effects of hUCMSCs and EVs were consistent with those in vivo. Therefore, hUCMSCs may be expected to serve as a new therapy for RA.

Preliminary Characterization of Extracellular Vesicles From Auditory HEI-OC1 Cells

Objectives:

Isolate, purify, and characterize extracellular vesicles (EVs) obtained from auditory HEI-OC1 cells, and evaluate their suitability for intracochlear transport and delivery of pharmacological drugs and/or pro-resolution mediators of acute inflammatory processes.

Methods:

HEI-OC1 EVs were isolated and purified using the exoEasy Maxi Kit, and their size was evaluated by nanoparticle tracking techniques. Bottom-up proteomics of the EVs, either freshly obtained or stored for up to 4 months at −20°C, was performed by LC-ESI-MS/MS. LC-ESI-MS/MS-MRM was used to measure the loading of dexamethasone inside EVs following co-incubation at room temperature for 1 hour with and without 5 minutes sonication.

Results:

Routinely, we were able to obtain purified fractions of >2 × 109 EVs/mL, with diameters varying between 50 and 800 nm. Bottom-up proteomics showed that among the most abundant EVs proteins, 19.2% were cytoplasmic, 17.2% were membrane localized, 12.3% were cytosolic, and 14.6% were nucleolar. No significant differences between fresh and stored EVs were detected. Importantly, co-incubation of HEI-OC1 EVs (1 × 108 EVs/mL) with dexamethasone (10 mM) resulted in the incorporation of 10.1 ± 1.9 nM dexamethasone per milliliter of EVs suspension.

Conclusions:

Altogether, the results suggest that EVs from HEI-OC1 cells could be advantageously used as biological nanocarriers for the delivery of specific molecules and pharmacological drugs into the inner ear.

Genetic Manipulation of Calcium Release-Activated Calcium Channel 1 Modulates the Multipotency of Human Cartilage-Derived Mesenchymal Stem Cells

Calcium is a ubiquitous intracellular messenger that has a crucial role in determining the proliferation, differentiation, and functions of multipotent mesenchymal stem cells (MSCs). Our study is aimed at elucidating the influence of genetically manipulating Ca²⁺ release-activated Ca²⁺ (CRAC) channel-mediated intercellular Ca²⁺ signaling on the multipotency of MSCs. The abilities of genetically engineered MSCs, including CRAC-overexpressing and CRAC-knockout MSCs, to differentiate into multiple mesenchymal lineages, including adipogenic, osteogenic, and chondrogenic lineages, were evaluated. CRAC channel-mediated Ca²⁺ influx into these cells was regulated, and the differentiation fate of MSCs was modified. Upregulation of intracellular Ca²⁺ signals attenuated the adipogenic differentiation ability and slightly increased the osteogenic differentiation potency of MSCs, whereas downregulation of CRACM1 expression promoted chondrogenic differentiation potency. The findings demonstrated the effects of genetically manipulating MSCs by targeting CRACM1. CRAC-modified MSCs had distinct differentiation fates to adipocytes, osteoblasts, and chondrocytes. To aid in the clinical implementation of tissue engineering strategies for joint regeneration, these data may allow us to identify prospective factors for effective treatments and could maximize the therapeutic potential of MSC-based transplantation.

Intravenous Infusion of Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Rheumatoid Arthritis: A Phase Ia Clinical Trial

Based on immunomodulatory actions of human umbilical cord blood‐derived mesenchymal stem cells (hUCB‐MSCs), in vitro or preclinical studies of hUCB‐MSCs have been conducted extensively in rheumatoid arthritis (RA). However, few human trials have investigated the outcomes of hUCB‐MSC infusions. The CURE‐iv trial was a phase I, uncontrolled, open label trial for RA patients with moderate disease activity despite treatment with methotrexate. The patients received a single intravenous infusion of 2.5 × 10⁷, 5 × 10⁷, or 1 × 10⁸ cells of hUCB‐MSCs for 30 minutes, three patients in each cluster, with an increment of cell numbers when there was no dose‐limited adverse event. Clinical and safety assessments were performed during the study period, and serum cytokines were measured at baseline and 24 hours after the infusion. Out of 11 screened RA patients, 9 were enrolled. The participants were predominantly female (78%) and the mean age was 57.4 years. The mean disease duration was 9.5 years, and baseline 28‐joint disease activity score (DAS28; using erythrocyte sedimentation rate) was 4.53. There was no major toxicity in all clusters up to 4 weeks after the infusion. Serum erythrocyte sedimentation rate changes at 4 weeks (n = 9) were −7.9 ± 10.4 (p = .0517) and DAS28 changes were −1.60 ± 1.57 (p = .0159). Reduced levels of IL‐1β, IL‐6, IL‐8, and TNF‐α at 24 hours were observed in the cluster infused with 1 × 10⁸ MSCs. This phase Ia hUCB‐MSC infusion trial for established RA patients revealed no short‐term safety concerns. Stem Cells Translational Medicine2018

Comparative Analysis between the In Vivo Biodistribution and Therapeutic Efficacy of Adipose-Derived Mesenchymal Stromal Cells Administered Intraperitoneally in Experimental Colitis

Mesenchymal stem cells (MSCs) have emerged as a promising treatment for inflammatory diseases. The immunomodulatory effect of MSCs takes place both by direct cell-to-cell contact and by means of soluble factors that leads to an increased accumulation of regulatory immune cells at the sites of inflammation. Similar efficacy of MSCs has been described regardless of the route of administration used, the inflammation conditions and the major histocompatibility complex context. These observations raise the question of whether the migration of the MSCs to the inflamed tissues is a pre-requisite to achieve their beneficial effect. To address this, we examined the biodistribution and the efficacy of intraperitoneal luciferase-expressing human expanded adipose-derived stem cells (Luci-eASCs) in a mouse model of colitis. Luci-eASC-infused mice were stratified according to their response to the Luci-eASC treatment. According to the stratification criteria, there was a tendency to increase the bioluminescence signal in the intestine at the expense of a decrease in the bioluminescence signal in the liver in the “responder” mice. These data thus suggest that the accumulation of the eASCs to the inflamed tissues is beneficial for achieving an optimal modulation of inflammation.

Mesenchymal stem cells for the management of rheumatoid arthritis: immune modulation, repair or both?

PURPOSE OF REVIEW

Mesenchymal stromal/stem cells (MSCs) have potent anti-inflammatory and immunomodulatory properties, in addition to their ability to form cartilage and bone. The purpose of this review is to highlight recent developments and current knowledge gaps in our understanding of the protective effects of MSCs against inflammatory arthritis, and to discuss their clinical exploitation for the treatment of rheumatoid arthritis (RA).

RECENT FINDINGS

The weight of evidence for protective mechanisms of exogenously administered MSCs is on immunomodulatory effects, including inhibition of dendritic cell maturation, polarization of macrophages to an anti-inflammatory phenotype, and activation of regulatory T cells, thereby dampening inflammation and preventing joint damage. Evidence for direct effects on tissue repair is scant. Recent studies have identified MSC subsets in vivo and an important question is whether MSCs in their native tissues have similar immunoregulatory functions. Recent proof-of-concept clinical studies have shown a satisfactory safety profile of allogeneic MSC therapy in RA patients with promising trends for clinical efficacy.

SUMMARY

Allogeneic MSCs could be effective in RA. Larger, multicentre clinical studies are needed to provide robust evidence, and MSC treatment at early stages of RA should be explored to 'reset' the immune system.

Mesenchymal stem/stromal cell extracellular vesicles: From active principle to next generation drug delivery system

It has been demonstrated that the biological effector of mesenchymal stem/stromal cells (MSCs) is their secretome, which is composed of a heterogeneous pool of bioactive molecules, partially enclosed in extracellular vesicles (EVs). Therefore, the MSC secretome (including EVs) has been recently proposed as possible alternative to MSC therapy. The secretome can be considered as a protein-based biotechnological product, it is probably safer compared with living/cycling cells, it presents virtually lower tumorigenic risk, and it can be handled, stored and sterilized as an Active Pharmaceutical/Principle Ingredient (API). EVs retain some structural and technological analogies with synthetic drug delivery systems (DDS), even if their potential clinical application is also limited by the absence of reproducible/scalable isolation methods and Good Manufacturing Practice (GMP)-compliant procedures. Notably, EVs secreted by MSCs preserve some of their parental cell features such as homing, immunomodulatory and regenerative potential. This review focuses on MSCs and their EVs as APIs, as well as DDS, considering their ability to reach inflamed and damaged tissues and to prolong the release of encapsulated drugs. Special attention is devoted to the illustration of innovative therapeutic approaches in which nanomedicine is successfully combined with stem cell therapy, thus creating a novel class of "next generation drug delivery systems."

Biodistribution and Efficacy of Human Adipose-Derived Mesenchymal Stem Cells Following Intranodal Administration in Experimental Colitis

Mesenchymal stem cells (MSCs) have a large potential in cell therapy for treatment of inflammatory and autoimmune diseases, thanks to their immunomodulatory properties. The encouraging results in animal models have initiated the translation of MSC therapy to clinical trials. In cell therapy protocols with MSCs, administered intravenously, several studies have shown that a small proportion of infused MSCs can traffic to the draining lymph nodes (LNs). This is accompanied with an increase of different types of regulatory immune cells in the LNs, suggesting the importance of migration of MSCs to the LNs in order to contribute to immunomodulatory response. Intranodal (IN), also referred as intralymphatic, injection of cells, like dendritic cells, is being proposed in the clinic for the treatment of cancer and allergy, showing that this route of administration is clinically safe and efficient. In this study, we investigated, for the first time, the biodistribution and the efficacy of Luciferase⁺ adipose-derived MSCs (Luci-eASCs), infused through the inguinal LNs (iLNs), in normal mice and in inflamed mice with colitis. Most of the Luci-eASCs remain in the iLNs and in the adipose tissue surrounding the inguinal LNs. A small proportion of Luci-eASCs can migrate to other locations within the lymphatic system and to other tissues and organs, having a preferential migration toward the intestine in colitic mice. Our results show that the infused Luci-eASCs protected 58% of the mice against induced colitis. Importantly, a correlation between the response to eASC treatment and a higher accumulation of eASCs in popliteal, parathymic, parathyroid, and mesenteric LNs were found. Altogether, these results suggest that IN administration of eASCs is feasible and may represent an effective strategy for cell therapy protocols with human adipose-derived MSCs in the clinic for the treatment of immune-mediated disorders.

Intralymphatic Administration of Adipose Mesenchymal Stem Cells Reduces the Severity of Collagen-Induced Experimental Arthritis

Mesenchymal stem cells (MSCs) are multipotent stromal cells with immunomodulatory properties. They have emerged as a very promising treatment for autoimmunity and inflammatory diseases such as rheumatoid arthritis. Previous studies have demonstrated that MSCs, administered systemically, migrate to lymphoid tissues associated with the inflammatory site where functional MSC-induced immune cells with a regulatory phenotype were increased mediating the immunomodulatory effects of MSCs. These results suggest that homing of MSCs to the lymphatic system plays an important role in the mechanism of action of MSCs in vivo. Thus, we hypothesized that direct intralymphatic (IL) (also referred as intranodal) administration of MSCs could be an alternative and effective route of administration for MSC-based therapy. Here, we report the feasibility and efficacy of the IL administration of human expanded adipose mesenchymal stem cells (eASCs) in a mouse model of collagen-induced arthritis (CIA). IL administration of eASCs attenuated the severity and progression of arthritis, reduced bone destruction and increased the levels of regulatory T cells (CD25⁺Foxp3⁺CD4⁺ cells) and Tr1 cells (IL10⁺CD4⁺), in spleen and draining lymph nodes. Taken together, these results indicate that IL administration of eASCs is very effective in modulating established CIA and may represent an alternative treatment modality for cell therapy with eASCs.

Etanercept-Synthesising Mesenchymal Stem Cells Efficiently Ameliorate Collagen-Induced Arthritis

Mesenchymal stem cells (MSCs) have multiple properties including anti-inflammatory and immunomodulatory effects in various disease models and clinical treatments. These beneficial effects, however, are sometimes inconsistent and unpredictable. For wider and proper application, scientists sought to improve MSC functions by engineering. We aimed to invent a novel method to produce synthetic biological drugs from engineered MSCs. We investigated the anti-arthritic effect of engineered MSCs in a collagen-induced arthritis (CIA) model. Biologics such as etanercept are the most successful drugs used in anti-cytokine therapy. Biologics are made of protein components, and thus can be theoretically produced from cells including MSCs. MSCs were transfected with recombinant minicircles encoding etanercept (trade name, Enbrel), which is a tumour necrosis factor α blocker currently used to treat rheumatoid arthritis. We confirmed minicircle expression in MSCs in vitro based on GFP. Etanercept production was verified from the conditioned media. We confirmed that self-reproduced etanercept was biologically active in vitro. Arthritis subsided more efficiently in CIA mice injected with mcTNFR2MSCs than in those injected with conventional MSCs or etanercept only. Although this novel strategy is in a very early conceptual stage, it seems to represent a potential alternative method for the delivery of biologics and engineering MSCs.

Human umbilical cord blood-stem cells direct macrophage polarization and block inflammasome activation to alleviate rheumatoid arthritis

Rheumatoid arthritis (RA) is a long-lasting intractable autoimmune disorder, which has become a substantial public health problem. Despite widespread use of biologic drugs, there have been uncertainties in efficacy and long-term safety. Mesenchymal stem cells (MSCs) have been suggested as a promising alternative for the treatment of RA because of their immunomodulatory properties. However, the precise mechanisms of MSCs on RA-related immune cells are not fully elucidated. The aim of this study was to investigate the therapeutic potential of human umbilical cord blood-derived MSCs (hUCB-MSCs) as a new therapeutic strategy for patients with RA and to explore the mechanisms underlying hUCB-MSC-mediated immunomodulation. Mice with collagen-induced arthritis (CIA) were administered with hUCB-MSCs after the onset of disease, and therapeutic efficacy was assessed. Systemic delivery of hUCB-MSCs significantly ameliorated the severity of CIA to a similar extent observed in the etanercept-treated group. hUCB-MSCs exerted this therapeutic effect by regulating macrophage function. To verify the regulatory effects of hUCB-MSCs on macrophages, macrophages were co-cultured with hUCB-MSCs. The tumor necrosis factor (TNF)-α-mediated activation of cyclooxygenase-2 and TNF-stimulated gene/protein 6 in hUCB-MSCs polarized naive macrophages toward an M2 phenotype. In addition, hUCB-MSCs down-regulated the activation of nucleotide-binding domain and leucine-rich repeat pyrin 3 inflammasome via a paracrine loop of interleukin-1β signaling. These immune-balancing effects of hUCB-MSCs were reproducible in co-culture experiments using peripheral blood mononuclear cells from patients with active RA. hUCB-MSCs can simultaneously regulate multiple cytokine pathways in response to pro-inflammatory cytokines elevated in RA microenvironment, suggesting that treatment with hUCB-MSCs could be an attractive candidate for patients with treatment-refractory RA.

Transplantation of gingiva-derived mesenchymal stem cells ameliorates collagen-induced arthritis

Background

Rheumatoid arthritis (RA) is a chronic, progressive, and inflammatory autoimmune disease which primarily affects the small arthrodial joints. The aim of this study was to test whether transplantation of mesenchymal stem cells derived from gingival tissue (GMSCs) could ameliorate collagen-induced arthritis (CIA), and to explore the role of the FasL/Fas pathway in the underlying mechanism.

Methods

DBA/1 mice with collagen II-induced arthritis were treated with GMSCs from the C57BL/6 J mouse, the B6Smn.C3-FasL^gld/J mouse (FasL^–/– GMSCs), and FasL overexpressed FasL^–/– GMSCs (FasL TF GMSCs). Inflammation was evaluated by measuring clinical score, tumor necrosis factor (TNF)-α and anti-collagen II antibody levels, and histological analyses. The levels of CD4⁺ Th cell subsets in spleens and draining lymph nodes were assessed by flow cytometric analysis.

Results

Systemic infusion of GMSCs can significantly reduce the severity of experimental arthritis, and resume the balance of Th cell subsets. FasL^–/– GMSCs failed to induce apoptosis of activated T cells in vitro and in vivo, and therefore show no therapeutic effects, whereas FasL TF GMSCs can rescue the immunosuppressant effects in the treatment of CIA.

Conclusions

GMSC-based therapy induces T-cell apoptosis via the FasL/Fas pathway and results in immune tolerance and amelioration of the CIA inflammation.

Stem Cell-Derived Extracellular Vesicles and Immune-Modulation

Extra-cellular vesicles (EVs) are bilayer membrane structures enriched with proteins, nucleic acids, and other active molecules and have been implicated in many physiological and pathological processes over the past decade. Recently, evidence suggests EVs to play a more dichotomic role in the regulation of the immune system, whereby an immune response may be enhanced or supressed by EVs depending on their cell of origin and its functional state. EVs derived from antigen (Ag)-presenting cells for instance, have been involved in both innate and acquired (or adaptive) immune responses, as Ag carriers or presenters, or as vehicles for delivering active signaling molecules. On the other hand, tumor and stem cell derived EVs have been identified to exert an inhibitory effect on immune responses by carrying immuno-modulatory effectors, such as transcriptional factors, non-coding RNA (Species), and cytokines. In addition, stem cell-derived EVs have also been reported to impair dendritic cell maturation and to regulate the activation, differentiation, and proliferation of B cells. They have been shown to control natural killer cell activity and to suppress the innate immune response (IIR). Studies reporting the role of EVs on T lymphocyte modulation are controversial. Discrepancy in literature may be due to stem cell culture conditions, methods of EV purification, EV molecular content, and functional state of both parental and target cells. However, mesenchymal stem cell-derived EVs were shown to play a more suppressive role by shifting T cells from an activated to a T regulatory phenotype. In this review, we will discuss how stem cell-derived EVs may contribute toward the modulation of the immune response. Collectively, stem cell-derived EVs mainly exhibit an inhibitory effect on the immune system.

Extracellular vesicles — new tool for joint repair and regeneration

Cell-derived extracellular vesicles (EVs), present in synovial fluid and cartilage extracellular matrix (ECM), are involved in joint development and in the regulation of joint homeostasis. Although the exact function of EVs in these processes remains incompletely defined, the knowledge already acquired in this field suggests a role for these EVs as biomarkers of joint disease, and as a new tool to restore joint homeostasis and enhance articular tissue regeneration. In addition to direct injection of therapeutic EVs into the target site, surface coating of scaffolds and embedding of EVs in hydrogels might also lead to novel therapeutic possibilities. Based on the existing literature of EVs in synovial fluid and articular tissues, and investigation of the molecular factors (including microRNAs) active in joint homeostasis (or during its disturbance), we postulate novel perspectives for the implementation of EVs as a regenerative medicine approach in joint repair.

Treatment of Collagen-Induced Arthritis Using Immune Modulatory Properties of Human Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have immune modulatory properties. We investigated the potential therapeutic effects of human bone marrow (BM)-, adipose tissue (AD)-, and cord blood (CB)-derived MSCs in an experimental animal model of rheumatoid arthritis (RA) and explored the mechanism underlying immune modulation by MSCs. We evaluated the therapeutic effect of clinically available human BM-, AD-, and CB-derived MSCs in DBA/1 mice with collagen-induced arthritis (CIA). CIA mice were injected intraperitoneally with three types of MSCs. Treatment control animals were injected with 35 mg/kg methotrexate (MTX) twice weekly. Clinical activity in CIA mice, degree of inflammation, cytokine expression in the joint, serum cytokine levels, and regulatory T cells (Tregs) were evaluated. Mice treated with human BM-, AD-, and CB-MSCs showed significant improvement in clinical joint score, comparable to MTX-treated mice. Histologic examination showed greatly reduced joint inflammation and damage in MSC-treated mice compared with untreated mice. Microcomputed tomography also showed little joint damage in the MSC-treated group. MSCs significantly decreased serum interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and interferon-γ and increased IL-10 and transforming growth factor-β levels. Tregs were increased in mice treated with MSCs compared to untreated or MTX-treated mice. Human BM-, AD-, and CB-MSCs significantly suppressed joint inflammation in CIA mice. The cells decreased proinflammatory cytokines and upregulated anti-inflammatory cytokines and induced Tregs. Therefore, our study suggests that the use of human BM-, AD-, and CB-MSCs could be an effective therapeutic approach for RA.

The murine Pbx1-d lupus susceptibility allele accelerates mesenchymal stem cell differentiation and impairs their immunosuppressive function

Pre–B cell leukemia homeobox 1 (Pbx1)-d is a dominant-negative splice isoform of the gene Pbx1 that corresponds to the NZM2410 lupus susceptibility locus Sle1a1. Pbx1 is required to maintain stem cell self-renewal, including that of mesenchymal stem cells (MSCs). MSCs have immunosuppressive functions that require stem cell maintenance. We tested the hypothesis that the expression of Pbx1-d favors MSC differentiation and impairs their immunosuppressive functions. We demonstrate that Sle1a1 MSCs express high levels of Pbx1-d as compared with congenic C57BL/6J (B6) MSCs. Sle1a1 MSCs grew faster and differentiated significantly more rapidly into osteoblasts than did B6 MSCs. This corresponded to a significant decrease in the expression of genes associated with stemness and an increase in the expression of genes associated with differentiation. Additionally, Sle1a1 MSCs express a gene expression profile associated with an enhanced innate immunity and inflammation. Suppression of Ig production from TLR-activated B6 B cells and IL-2 secretion from activated B6 CD4+ T cells was significantly impaired in Sle1a1 MSCs as compared with B6 MSCs. B6.Sle1a1 MSCs showed intermediate activity in suppressing lupus immunophenotypes in three different mouse models. Taken together, these data suggest that the expression of the lupus susceptibility allele Pbx1-d isoform impairs MSC functions, which may contribute to lupus pathogenesis both through a defective immunosuppression and the promotion of a proinflammatory environment.

Mesenchymal stem cells and their secreted molecules predominantly ameliorate fulminant hepatic failure and chronic liver fibrosis in mice respectively

BACKGROUND

Orthotopic liver transplantation is the only effective treatment for liver failure but limited with shortage of available donor organs. Recent studies show promising results of mesenchymal stem cells (MSCs)-based therapies.

METHODS

We systematically investigate the therapeutic effects of MSCs or MSC-conditioned medium (MSC-CM) in ameliorating fulminant hepatic failure (FHF) and chronic liver fibrosis in mice. In addition, extensive flow cytometry analysis of spleens from vehicle and MSC- and MSC-CM-treated mice was applied to reveal the alteration of inflammatory state.

RESULTS

In FHF model, MSCs treatment reduced remarkably the death incidents; the analysis of gross histopathology showed that control livers were soft and shrunken with extensive extravasated blood, which was gradually reduced at later time points, while MSC-treated livers showed gross pathological changes, even 24 h after MSC infusion, and hematoxylin and eosin staining revealed dramatical hepatocellular death with cytoplasmic vacuolization suppressed by MSCs treatment; flow cytometry analysis of total lymphocytes showed that macrophages (F4/80) infiltrated into control livers more than MSC-treated livers; by contrast, MSC-CM partially ameliorates FHF. In chronic liver injury model, MSC and MSC-CM both suppressed fibrogenesis and necroinflammatory, and the later was better; activation of hepatic stellate cells (α-SMA) was inhibited; glycogen synthesis and storage (indicated by periodic acid-Schiff -staining) was improved; liver regeneration (Ki67) was promoted while liver apoptosis (TUNEL) was reduced. In the in vitro, MSCs promote macrophage line RAW264.7 apoptosis and MSC-CM promotes apoptosis and inhibits proliferation of HSC line LX-2. We also found that MSCs and MSC-CM could improve spleen; MSC-CM increased levels of Th2 and Treg cells, and reduced levels of Th17 cells, whereas levels of Th1 cells were unchanged; comparatively, MSC treatment did not affect Th17 and Treg cells and only slightly alters inflammatory state; MSC and MSC-CM treatment both substantially down-regulated macrophages in the spleens.

CONCLUSION

Both MSCs and MSC-CM exert therapeutic effects by acting on various key cells during the pathogenesis of FHF and chronic fibrosis, stimulating hepatocyte proliferation and suppressing apoptosis, down-regulating infiltrating macrophages, converting CD4(+) T lymphocyte system into an anti-inflammatory state, and facilitating hepatic stellate cell death.

Applying extracellular vesicles based therapeutics in clinical trials - an ISEV position paper

Extracellular vesicles (EVs), such as exosomes and microvesicles, are released by different cell types and participate in physiological and pathophysiological processes. EVs mediate intercellular communication as cell-derived extracellular signalling organelles that transmit specific information from their cell of origin to their target cells. As a result of these properties, EVs of defined cell types may serve as novel tools for various therapeutic approaches, including (a) anti-tumour therapy, (b) pathogen vaccination, (c) immune-modulatory and regenerative therapies and (d) drug delivery. The translation of EVs into clinical therapies requires the categorization of EV-based therapeutics in compliance with existing regulatory frameworks. As the classification defines subsequent requirements for manufacturing, quality control and clinical investigation, it is of major importance to define whether EVs are considered the active drug components or primarily serve as drug delivery vehicles. For an effective and particularly safe translation of EV-based therapies into clinical practice, a high level of cooperation between researchers, clinicians and competent authorities is essential. In this position statement, basic and clinical scientists, as members of the International Society for Extracellular Vesicles (ISEV) and of the European Cooperation in Science and Technology (COST) program of the European Union, namely European Network on Microvesicles and Exosomes in Health and Disease (ME-HaD), summarize recent developments and the current knowledge of EV-based therapies. Aspects of safety and regulatory requirements that must be considered for pharmaceutical manufacturing and clinical application are highlighted. Production and quality control processes are discussed. Strategies to promote the therapeutic application of EVs in future clinical studies are addressed.

Leptin and Neutrophil-Activating Peptide 2 Promote Mesenchymal Stem Cell Senescence Through Activation of the Phosphatidylinositol 3-Kinase/Akt Pathway in Patients With Systemic Lupus Erythematosus

OBJECTIVE

Mesenchymal stem cells (MSCs) derived from patients with systemic lupus erythematosus (SLE) exhibit enhanced senescence. Cellular senescence has been reported to be induced by several inflammatory cytokines, including interferon-α (IFNα) and IFNγ, that are involved in the pathogenesis of SLE. We undertook this study to investigate whether the inflammatory environment in SLE could affect MSC senescence.

METHODS

Cellular senescence was measured by staining of senescence-associated β-galactosidase and by expression of the cell cycle inhibitors p53 and p21. Eighty cytokines and chemokines in serum from healthy controls and patients with SLE were identified by cytokine antibody array.

RESULTS

SLE serum promoted senescence of MSCs, which was reversed by the phosphatidylinositol 3-kinase (PI3K)/Akt signaling inhibitor LY294002 but not by the JAK/STAT inhibitor AG490 and not by the MEK/ERK inhibitor PD98059. Cytokine antibody array analysis revealed that leptin and neutrophil-activating peptide 2 (NAP-2) were the 2 factors most significantly elevated in SLE serum compared with normal serum. Blockade of leptin or NAP-2 in MSC cultures abolished SLE serum-induced senescence, while direct addition of these 2 factors could promote senescence in cultures of normal MSCs. Inhibition of PI3K/Akt signaling with LY294002 reduced leptin- and NAP-2-induced senescence in MSCs.

CONCLUSION

Taken together, our data show that leptin and NAP-2 act synergistically to promote MSC senescence through enhancement of the PI3K/Akt signaling pathway in SLE patients.

Glucocorticoid-induced leucine zipper governs the therapeutic potential of mesenchymal stem cells by inducing a switch from pathogenic to regulatory Th17 cells in a mouse model of collagen-induced arthritis

OBJECTIVE

Mesenchymal stem cells (MSCs) are potent immunosuppressive cells that have shown promise in the treatment of rheumatoid arthritis (RA). Deciphering the intrinsic characteristics of MSCs that correlate with their biologic activity will facilitate their clinical use. Recently, the role of glucocorticoid-induced leucine zipper (GILZ) in the development of RA has been documented. The aim of this study was to evaluate whether GILZ expression by MSCs may contribute to their therapeutic effect.

METHODS

MSCs were isolated from GILZ-deficient (GILZ(-/-) ) mice and wild-type mice. MSCs (1 × 10(6) cells) were injected twice via the tail vein into mice with collagen-induced arthritis (CIA).

RESULTS

In vitro, we showed that GILZ is a key factor involved in the immunosuppressive potential of MSCs. MSCs derived from GILZ(-/-) mice did not suppress the proliferation of CD4+ T cells and were less efficient than MSCs derived from WT mice in altering Th17 cell polarization. Thus, we investigated the role of GILZ in an experimental model of arthritis and demonstrated that although WT MSCs significantly reduced paw swelling in arthritic mice, GILZ(-/-) MSCs did not. Moreover, the magnitude of the effects of GILZ(-/-) MSCs on Th17 cell frequency was significantly lower than that of WT MSCs. The therapeutic effect of MSCs correlated with the generation of Treg cells bearing the CD4 + RORγt+IL-17(low) IL-10+ signature, and Th17 cell polarization was GILZ dependent.

CONCLUSION

This study demonstrates that GILZ has an essential role in the therapeutic effectiveness of MSCs in arthritis by favoring Th17 cell polarization toward a regulatory phenotype. Therefore, potentiation of GILZ expression in MSCs could represent a means to enhance their therapeutic effect in autoimmune diseases.

Are mesenchymal stem cells in rheumatoid arthritis the good or bad guys?

The advancements in our understanding of the inflammatory and immune mechanisms in rheumatoid arthritis (RA) have fuelled the development of targeted therapies that block cytokine networks and pathogenic immune cells, leading to a considerable improvement in the management of RA patients. Nonetheless, no therapy is curative and clinical remission does not necessarily correspond to non-progression of joint damage. Hence, the biomedical community has redirected scientific efforts and resources towards the investigation of other biological aspects of the disease, including the mechanisms driving tissue remodelling and repair. In this regard, stem cell research has attracted extraordinary attention, with the ultimate goal to develop interventions for the biological repair of damaged tissues in joint disorders, including RA. The recent evidence that mesenchymal stem cells (MSCs) with the ability to differentiate into cartilage are present in joint tissues raises an opportunity for therapeutic interventions via targeting intrinsic repair mechanisms. Under physiological conditions, MSCs in the joint are believed to contribute to the maintenance and repair of joint tissues. In RA, however, the repair function of MSCs appears to be repressed by the inflammatory milieu. In addition to being passive targets, MSCs could interact with the immune system and play an active role in the perpetuation of arthritis and progression of joint damage. Like MSCs, fibroblast-like synoviocytes (FLSs) are part of the stroma of the synovial membrane. During RA, FLSs undergo proliferation and contribute to the formation of the deleterious pannus, which mediates damage to articular cartilage and bone. Both FLSs and MSCs are contained within the mononuclear cell fraction in vitro, from which they can be culture expanded as plastic-adherent fibroblast-like cells. An important question to address relates to the relationship between MSCs and FLSs. MSCs and FLSs could be the same cell type with functional specialisation or represent different functional stages of the same stromal lineage. This review will discuss the roles of MSCs in RA and will address current knowledge of the relative identity between MSCs and FLSs. It will also examine the immunomodulatory properties of the MSCs and the potential to harness such properties for the treatment of RA.

Local delivery of mesenchymal stem cells with poly-lactic-co-glycolic acid nano-fiber scaffold suppress arthritis in rats

Mesenchymal stem cells (MSC) have been used recently for the treatment of autoimmune diseases in murine animal models due to the immunoregulatory capacity. Current utilization of MSC requires cells in certain quantity with multiple courses of administration, leading to limitation in clinical usage. Here we efficiently treated collagen-induced arthritis rats with a single local implantation with reduced number of MSC (2∼20% of previous studies) with nano-fiber poly-lactic-co-glycolic acid (nano-fiber) scaffold. MSC seeded on nano-fiber scaffold suppressed arthritis and bone destruction due to inhibition of systemic inflammatory reaction and immune response by suppressing T cell proliferation and reducing anti- type II collagen antibody production. In vivo tracing of MSC demonstrated that these cells remained within the scaffold without migrating to other organs. Meanwhile, in vitro culture of MSC with nano-fiber scaffold significantly increased TGF-β1 production. These results indicate an efficient utilization of MSC with the scaffold for destructive joints in rheumatoid arthritis by a single and local inoculation. Thus, our data may serve as a new strategy for MSC-based therapy in inflammatory diseases and an alternative delivery method for bone destruction treatment.

Biotechnological and biomedical applications of mesenchymal stem cells as a therapeutic system

Mesenchymal stem cells (MSCs) are non-hematopoietic, multipotent progenitor cells which reside in bone marrow (BM), support homing of hematopoietic stem cells (HSCs) and self-renewal in the BM. These cells have the potential to differentiate into tissues of mesenchymal origin, such as fibroblasts, adipocytes, cardiomyocytes, and stromal cells. MSCs can express surface molecules like CD13, CD29, CD44, CD73, CD90, CD166, CXCL12 and toll-like receptors (TLRs). Different factors, such as TGF-β, IL-10, IDO, PGE-2, sHLA-G5, HO, and Galectin-3, secreted by MSCs, induce interaction in cell to cell immunomodulatory effects on innate and adaptive cells of the immune system. Furthermore, these cells can stimulate and increase the TH2 and regulatory T-cells through inhibitory effects on the immune system. MSCs originate from the BM and other tissues including the brain, adipose tissue, peripheral blood, cornea, thymus, spleen, fallopian tube, placenta, Wharton's jelly and umbilical cord blood. Many studies have focused on two significant features of MSC therapy: (I) MSCs can modulate T-cell-mediated immunological responses, and (II) systemically administered MSCs home in to sites of ischemia or injury. In this review, we describe the known mechanisms of immunomodulation and homing of MSCs. As a result, this review emphasizes the functional role of MSCs in modulating immune responses, their capability in homing to injured tissue, and their clinical therapeutic potential.

Intra-articular injection of mesenchymal stem cells leads to reduced inflammation and cartilage damage in murine antigen-induced arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a debilitating and painful disease leading to increased morbidity and mortality and novel therapeutic approaches are needed. The purpose of this study was to elucidate if mesenchymal stem cells (MSCs) injected in the joints of mice with arthritis are therapeutic, reducing joint swelling and cartilage destruction.

METHODS

Murine mesenchymal stem cells (mMSCs) were isolated from bone marrow of C57Bl/6 mice and expanded in culture. Cells were tested for immunophenotype and their ability to form colonies and to differentiate into chondrocytes, osteocytes and adipocytes. Antigen-induced arthritis (AIA) was induced by intra-articular injection of methylated bovine serum albumin into the knee joints of preimmunized C57Bl/6 mice. After one day, when peak swelling occurs, 500,000 mMSCs labelled with red fluorescent cell tracker CM-DiI were injected intra-articularly in the right knee joint. Left knee joints were treated as controls by receiving PBS injections. Differences between groups were calculated by Mann Whitney U test or unpaired t tests using GraphPad Prism software version 5.

RESULTS

Knee joint diameter (swelling) was measured as a clinical indication of joint inflammation and this parameter was significantly less in MSC-treated mice compared to control-treated animals 48 hours after arthritis induction. This difference continued for ~7 days. CM-DiI-labelled MSCs were clearly visualised in the lining and sublining layers of synovium, in the region of the patella and femoral and tibial surfaces. By day 3, parameters indicative of disease severity, including cartilage depletion, inflammatory exudate and arthritic index were shown to be significantly reduced in MSC-treated animals. This difference continued for 7 days and was further confirmed by histological analysis. The serum concentration of tumour necrosis factor α was significantly decreased following MSC administration.

CONCLUSIONS

Our results reveal that MSCs injected in the joints of mice with AIA are therapeutic, reducing inflammation, joint swelling and cartilage destruction. These cells also integrate into the synovium in AIA.

Effect of TNFα on osteoblastogenesis from mesenchymal stem cells

BACKGROUND

Bone destruction and osteoporosis are accelerated in chronic inflammatory diseases, such as rheumatoid arthritis (RA) and periodontitis, in which many studies have shown the proinflammatory cytokines, especially TNFα, play an important role; TNFα causes osteoclast-induced bone destruction as well as the inhibition of osteoblastogenesis.

SCOPE OF REVIEW

Here we review our current understanding of the mechanism of the effect of TNFα on osteoblastogenesis from mesenchymal stem cells (MSCs). We also highlight the function of MSC in the pathogenesis of autoimmune diseases.

MAJOR CONCLUSIONS

Many studies have revealed that TNFα inhibits osteoblastogenesis through several mechanisms. On the other hand, it has been also reported that TNFα promotes osteoblastogenesis. These discrepancies may depend on the cellular types, the model animals, and the timing and duration of TNFα administration.

GENERAL SIGNIFICANCE

A full understanding of the role and function of TNFα on osteoblastogenesis from MSC may lead to targeted new therapies for chronic inflammation diseases, such as RA and periodontitis.

Extracellular membrane vesicles from umbilical cord blood-derived MSC protect against ischemic acute kidney injury, a feature that is lost after inflammatory conditioning

Background

Mesenchymal stromal cells (MSC) are shown to have a great therapeutic potential in many immunological disorders. Currently the therapeutic effect of MSCs is considered to be mediated via paracrine interactions with immune cells. Umbilical cord blood is an attractive but still less studied source of MSCs. We investigated the production of extracellular membrane vesicles (MVs) from human umbilical cord blood derived MSCs (hUCBMSC) in the presence (MVstim) or absence (MVctrl) of inflammatory stimulus.

Methods

hUCBMSCs were cultured in serum free media with or without IFN-γ and MVs were collected from conditioned media by ultracentrifugation. The protein content of MVs were analyzed by mass spectrometry. Hypoxia induced acute kidney injury rat model was used to analyze the in vivo therapeutic potential of MVs and T-cell proliferation and induction of regulatory T cells were analyzed by co-culture assays.

Results

Both MVstim and MVctrl showed similar T-cell modulation activity in vitro, but only MVctrls were able to protect rat kidneys from reperfusion injury in vivo. To clarify this difference in functionality we made a comparative mass spectrometric analysis of the MV protein contents. The IFN-γ stimulation induced dramatic changes in the protein content of the MVs. Complement factors (C3, C4A, C5) and lipid binding proteins (i.e apolipoproteins) were only found in the MVctrls, whereas the MVstim contained tetraspanins (CD9, CD63, CD81) and more complete proteasome complex accompanied with MHCI. We further discovered that differently produced MV pools contained specific Rab proteins suggesting that same cells, depending on external signals, produce vesicles originating from different intracellular locations.

Conclusions

We demonstrate by both in vitro and in vivo models accompanied with a detailed analysis of molecular characteristics that inflammatory conditioning of MSCs influence on the protein content and functional properties of MVs revealing the complexity of the MSC paracrine regulation.

Implications of multipotent mesenchymal stromal cell aging

Aging is defined as the progressive and generalized impairment of function, resulting in an increasing vulnerability to environmental challenges and a growing risk of disease and death. The decline in the regenerative capacity of resident stem cells across different tissues is a central mediator of aging. In this paper we review the evidence implicating multipotent mesenchymal stromal cells as being subject to and causes of tissue and organismal aging. We specifically discuss the nuclear changes that occur in the context of Hutchinson-Gilford progeria syndrome, a premature aging syndrome that preferentially affects tissues of mesenchymal origin.

Could mesenchymal stromal cells have a role in childhood autoimmune diseases?

Mesenchymal stromal cells (MSCs) comprise a promising source for cellular therapy due to their ability to be readily isolated from various tissues and expand ex vivo. A unique property of these cells is the modulation of immune responses, making them attractive candidates for the treatment of autoimmune diseases. Recently, several clinical trials, mainly in adults, suggest the use of MSCs for therapy of refractory autoimmune diseases. There are a very limited number of reports in the literature addressing the cellular therapy options for pediatric patients with autoimmune diseases refractory to standard therapy. This review discusses the possible mechanisms underlying the immunosuppressive effects of MSCs on almost all cell types, and also the recent advances in cellular therapy of autoimmune diseases using MSCs as modulators of immune response, especially in children.

Fibroblast growth factor-1 is a mesenchymal stromal cell-secreted factor stimulating proliferation of osteoarthritic chondrocytes in co-culture

Previously, we showed that mesenchymal stromal cells (MSCs) in co-culture with primary chondrocytes secrete soluble factors that increase chondrocyte proliferation. The objective of this study is to identify these factors. Human primary chondrocytes (hPCs) isolated from late-stage osteoarthritis patients were co-cultured with human bone marrow-derived MSCs (hMSCs) in pellets. Genome-wide mRNA expression analysis and quantitative polymerase chain reactions (qPCR) were used to identify soluble factors that were specifically induced in co-cultures. Immunofluorescent staining combined with cell tracking and enzyme-linked immunosorbent assay (ELISA) were performed to validate up-regulation at the protein level and to identify the cellular origin of the increased proteins. Chemical blockers and neutralizing antibodies were used to elucidate the role of the identified candidate genes in co-cultures. A number of candidate factors were differentially regulated in co-cultures at the mRNA level. Of these, fibroblast growth factor-1 (FGF-1) mRNA and protein expression were markedly increased in co-cultures predominantly due to up-regulated expression in MSCs. Blocking of FGF signaling in co-culture pellets by specific FGF receptor inhibitors or FGF-1 neutralizing antibodies completely blocked hPCs proliferation. We demonstrate that MSCs increase FGF-1 secretion on co-culture with hPCs, which, in turn, is responsible for increased hPCs proliferation in pellet co-cultures.

Mesenchymal stem cells in regenerative medicine applied to rheumatic diseases: role of secretome and exosomes

Over the last decades, mesenchymal stem cells (MSCs) have been extensively studied with regard to their potential applications in regenerative medicine. In rheumatic diseases, MSC-based therapy is the subject of great expectations for patients who are refractory to proposed treatments such as rheumatoid arthritis (RA), or display degenerative injuries without possible curative treatment, such as osteoarthritis (OA). The therapeutic potential of MSCs has been demonstrated in several pre-clinical models of OA or RA and both the safety and efficacy of MSC-based therapy is being evaluated in humans. The predominant mechanism by which MSCs participate to tissue repair is through a paracrine activity. Via the production of a multitude of trophic factors with various properties, MSCs can reduce tissue injury, protect tissue from further degradation and/or enhance tissue repair. However, a thorough in vivo examination of MSC-derived secretome and strategies to modulate it are still lacking. The present review discusses the current understanding of the MSC secretome as a therapeutic for treatment of inflammatory or degenerative pathologies focusing on rheumatic diseases. We provide insights on and perspectives for future development of the MSC secretome with respect to the release of extracellular vesicles that would have certain advantages over injection of living MSCs or administration of a single therapeutic factor or a combination of factors.

Endometrial regenerative cells for treatment of heart failure: a new stem cell enters the clinic

Heart failure is one of the key causes of morbidity and mortality world-wide. The recent findings that regeneration is possible in the heart have made stem cell therapeutics the Holy Grail of modern cardiovascular medicine. The success of cardiac regenerative therapies hinges on the combination of an effective allogeneic “off the shelf” cell product with a practical delivery system. In 2007 Medistem discovered the Endometrial Regenerative Cell (ERC), a new mesenchymal-like stem cell. Medistem and subsequently independent groups have demonstrated that ERC are superior to bone marrow mesenchymal stem cells (MSC), the most widely used stem cell source in development. ERC possess robust expansion capability (one donor can generate 20,000 patients doses), key growth factor production and high levels of angiogenic activity. ERC have been published in the peer reviewed literature to be significantly more effect at treating animal models of heart failure (Hida et al. Stem Cells 2008).

Current methods of delivering stem cells into the heart suffer several limitations in addition to poor delivery efficiency. Surgical methods are highly invasive, and the classical catheter based techniques are limited by need for sophisticated cardiac mapping systems and risk of myocardial perforation. Medistem together with Dr. Amit Patel Director of Clinical Regenerative Medicine at University of Utah have developed a novel minimally invasive delivery method that has been demonstrated safe and effective for delivery of stem cells (Tuma et al. J Transl Med 2012). Medistem is evaluating the combination of ERC, together with our retrograde delivery procedure in a 60 heart failure patient, double blind, placebo controlled phase II trial. To date 17 patients have been dosed and preliminary analysis by the Data Safety Monitoring Board has allowed for trial continuation.

The combined use of a novel “off the shelf” cell together with a minimally invasive 30 minute delivery method provides a potentially paradigm-shifting approach to cardiac regenerative therapy.

Do mesenchymal stem cells function across species barriers? Relevance for xenotransplantation

BACKGROUND

Allogeneic mesenchymal stem (stromal) cells (MSC) are a promising therapy for various pathological conditions. Genetically modified pig MSC have been demonstrated to downregulate the human T-cell response to pig antigens in vitro. Before genetically modified pig MSC can be used clinically, however, evidence needs to be provided to indicate whether they will survive in a human (xenogeneic) host.

LITERATURE SEARCH AND RESULTS

A literature search through the end of 2011 identified 94 reports of the in vivo cross-species administration of MSC in a variety of experimental models. The majority (n = 89) involved the use of human MSC in various other species, with an occasional study using pig, rat, or guinea-pig MSC. When human MSC were used, they were largely derived from the bone marrow, adipose tissue, or umbilical cord blood. The routes of administration were varied, although almost half of the studies utilized the intravenous route. In 88 experiments (93.6%), there was evidence that the MSC engrafted and functioned across the species barrier, and in only six cases (6.4%) was there evidence of failure to function. Importantly, MSC function was confirmed in several different cross-species models. For example, human MSC functioned in no fewer than seven different recipient species.

CONCLUSIONS

The data provided by this literature search strengthen the hypothesis that pig MSC will function satisfactorily in a different species, for example, humans. The data also suggest that our own in vitro observations on the efficacy of pig MSC in downregulating the strength of the human T-cell response to pig antigens will likely be reproduced in vivo in pre-clinical large animal models and in clinical trials.