Adipose-Derived Mesenchymal Stem Cells Prevent Systemic Bone Loss in Collagen-Induced Arthritis

The Role of Mesenchymal Stromal Cells in the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterised by the formation of a hyperplastic pannus, as well as cartilage and bone damage. The pathogenesis of RA is complex and involves broad interactions between various cells present in the inflamed synovium, including fibroblast-like synoviocytes (FLSs), macrophages, and T cells, among others. Under inflammatory conditions, these cells are activated, further enhancing inflammatory responses and angiogenesis and promoting bone and cartilage degradation. Novel treatment methods for RA are greatly needed, and mesenchymal stromal cells (MSCs) have been suggested as a promising new regenerative and immunomodulatory treatment. In this paper, we present the interactions between MSCs and RA-FLSs, and macrophages and T cells, and summarise studies examining the use of MSCs in preclinical and clinical RA studies.

Mesenchymal Stem Cells in the Pathogenesis and Therapy of Autoimmune and Autoinflammatory Diseases

Mesenchymal stem cells (MSCs) modulate immune responses and maintain self-tolerance. Their trophic activities and regenerative properties make them potential immunosuppressants for treating autoimmune and autoinflammatory diseases. MSCs are drawn to sites of injury and inflammation where they can both reduce inflammation and contribute to tissue regeneration. An increased understanding of the role of MSCs in the development and progression of autoimmune disorders has revealed that MSCs are passive targets in the inflammatory process, becoming impaired by it and exhibiting loss of immunomodulatory activity. MSCs have been considered as potential novel cell therapies for severe autoimmune and autoinflammatory diseases, which at present have only disease modifying rather than curative treatment options. MSCs are emerging as potential therapies for severe autoimmune and autoinflammatory diseases. Clinical application of MSCs in rare cases of severe disease in which other existing treatment modalities have failed, have demonstrated potential use in treating multiple diseases, including rheumatoid arthritis, systemic lupus erythematosus, myocardial infarction, liver cirrhosis, spinal cord injury, multiple sclerosis, and COVID-19 pneumonia. This review explores the biological mechanisms behind the role of MSCs in autoimmune and autoinflammatory diseases. It also covers their immunomodulatory capabilities, potential therapeutic applications, and the challenges and risks associated with MSC therapy.

Interactions of mesenchymal stromal/stem cells and immune cells following MSC-based therapeutic approaches in rheumatoid arthritis

Rheumatoid arthritis (RA) is considered to be a degenerative and progressive autoimmune disorder. Although several medicinal regimens are used to treat RA, potential adverse events such as metabolic disorders and increased risk of infection, as well as drug resistance in some patients, make it essential to find an effective and safe therapeutic approach. Mesenchymal stromal/stem cells (MSCs) are a group of non-hematopoietic stromal cells with immunomodulatory and inhibitory potential. These cells exert their regulatory properties through direct cell-to-cell interactions and paracrine effects on various immune and non-immune cells. As conventional therapeutic approaches for RA are limited due to their side effects, and some patients became refractory to the treatment, MSCs are considered as a promising alternative treatment for RA. In this review, we introduced various experimental and clinical studies conducted to evaluate the therapeutic effects of MSCs on animal models of arthritis and RA patients. Then, possible modulatory and suppressive effects of MSCs on different innate and adaptive immune cells, including dendritic cells, neutrophils, macrophages, natural killer cells, B lymphocytes, and various subtypes of T cells, were categorized and summarized. Finally, limitations and future considerations for the efficient application of MSCs as a therapeutic approach in RA patients were presented.

Cell-based therapies for the treatment of rheumatoid arthritis

Autoimmune diseases, including rheumatoid arthritis that is the most prevalent rheumatic autoimmune disorder, affect autologous connective tissues caused by the breakdown of the self-tolerance mechanisms of the immune system. During the last two decades, cell-based therapy, including stem cells and none-stem cells has been increasingly considered as a therapeutic option in various diseases. This is partly due to the unique properties of stem cells that divide and differentiate from the specialized cells in the damaged tissue. Moreover, stem cells and none-stem cells, impose immunomodulatory properties affecting the diseases caused by immunological abnormalities such as rheumatic autoimmune disorders. In the present review, the efficacy of cell-based therapy with four main types of stem cells, including mesenchymal stem cells, hematopoietic stem cells, embryonic stem cells, and human amniotic membrane cells, as well as none-stem cells, including regulatory T cells, chimeric antigen receptor T cells, and tolerogenic dendritic cells will be evaluated. Moreover, other related issues, including safety, changes in immunological parameters, suitable choice of stem cell and none-stem cell origin, conditioning regimen, limitations, and complications will be discussed.

Mesenchymal Stem/Stromal Cell-Based Therapies in Systemic Rheumatic Disease: From Challenges to New Approaches for Overcoming Restrictions

Systemic rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis, are chronic autoimmune diseases affecting multiple organs and tissues. Despite recent advances in treatment, patients still experience significant morbidity and disability. Mesenchymal stem/stromal cell (MSC)-based therapy is promising for treating systemic rheumatic diseases due to the regenerative and immunomodulatory properties of MSCs. However, several challenges need to be overcome to use MSCs in clinical practice effectively. These challenges include MSC sourcing, characterization, standardization, safety, and efficacy issues. In this review, we provide an overview of the current state of MSC-based therapies in systemic rheumatic diseases, highlighting the challenges and limitations associated with their use. We also discuss emerging strategies and novel approaches that can help overcome the limitations. Finally, we provide insights into the future directions of MSC-based therapies for systemic rheumatic diseases and their potential clinical applications.

Fluidic Device System for Mechanical Processing and Filtering of Human Lipoaspirate Enhances Recovery of Mesenchymal Stem Cells

BACKGROUND

Adipose tissue is an easily accessible source of stem and progenitor cells that offers exciting promise as an injectable autologous therapeutic for regenerative applications. Mechanical processing is preferred over enzymatic digestion, and the most common method involves shuffling lipoaspirate between syringes and filtering to produce nanofat. Although nanofat has shown exciting clinical results, the authors hypothesized that new device designs could enhance recovery of stem/progenitor cells through optimization of fluid dynamics principles, integration, and automation.

METHODS

The authors designed and fabricated the emulsification and micronization device (EMD) and the filtration device (FD) to replace the manual nanofat procedures. Using human lipoaspirate samples, the EMD and the FD were optimized and compared to traditional nanofat using ex vivo measurements of cell number, viability, and percentage of mesenchymal stem cells and endothelial progenitor cells.

RESULTS

The EMD produced results statistically similar to nanofat, and these findings were confirmed for a cohort of diabetic patients. Combining the FD with the EMD was superior to manually filtered nanofat in terms of both recovered cell percentages (>1.5-fold) and numbers (two- to three-fold). Differences were statistically significant for total mesenchymal stem cells and a DPP4 + /CD55 + subpopulation linked to improved wound healing in diabetes.

CONCLUSIONS

The new EMD and the FD improved mechanical processing of human lipoaspirate in terms of mesenchymal stem cell enrichment and number compared to traditional nanofat. Future work will seek to investigate the wound healing response both in vitro and in vivo, and to refine the technology for automated operation within clinical settings.

CLINICAL RELEVANCE STATEMENT

The new devices improved mechanical processing of human lipoaspirate in terms of stem cell enrichment and number compared to traditional methods. Future work will seek to validate wound healing response and refine the technology for automated operation within clinical settings.

IL-3 regulates the differentiation of pathogenic Th17 cells

IL-17 producing Th17 cells play an important role in pathogenesis of rheumatoid arthritis (RA). Aberrant immune activation due to imbalance between Th17 and regulatory T (Treg) cells is associated with development of RA and other autoimmune diseases. Targeting pathogenic Th17 cells and their associated molecules is emerging as a promising strategy to treat and reverse RA. Here, we demonstrate that IL-3 inhibits the differentiation of Th17 cells and promotes the development of Treg cells in IL-2-dependent manner. In IL-2 knockout mice, we observed that IL-3 has no effect on differentiation of both Th17 and Treg cells. In addition, IL-3 decreases pathogenic IL-17A⁺ TNF-α⁺ , IL-17A⁺ IFN-γ⁺ and IL-23R⁺ Th17 cells, secretion of GM-CSF and IFN-γ, and osteoclastogenesis when presented in the culture together with Th-17 polarizing cytokines. Mechanistically, IL-3 regulates the development of Th17 cells through inhibition of STAT3 phosphorylation. IL-3 treatment significantly decreases the pathogenic Th17 cell responses and arthritic scores in mouse model of RA. Importantly, IL-3 inhibits differentiation of human Th17 cells. Thus, our results suggest a novel therapeutic role of IL-3 in regulation of Th17 cell-mediated pathophysiology of RA. This article is protected by copyright. All rights reserved.

Total Saponins of Radix Clematis Regulate Fibroblast-Like Synoviocyte Proliferation in Rheumatoid Arthritis via the LncRNA OIP5-AS1/MiR-410-3p/Wnt7b Signaling Pathway

Background

Rheumatoid arthritis (RA) is the most common autoimmune disease and affects multiple joints. Previous studies have shown that total saponins of Radix clematidis (TSC) have a clear therapeutic effect on RA, but the specific mechanism has not yet been clarified. Literature screening and previous research suggest that the lncRNA OIP5-AS1/miR-410-3p/Wnt7b signaling pathway exerts a regulatory effect on the pathogenesis of RA. In this study, we examined whether the TSC treatment of RA affects the lncRNA OIP5-AS1/miR-410-3p/Wnt7b pathway.

Materials and Methods

Freund's complete adjuvant was used to create an adjuvant arthritis (AA) rat model with rat synovial cells being harvested and cultured. The experiment comprises a normal group, model group, TSC optimal-dose group, TSC optimal-dose group + lncRNA OIP5-AS1siRNA group, lncRNA OIP5-AS1 siRNA group, and lncRNA OIP5-AS1 siRNA + NC group. MMT was used to screen the optimal concentration of TSC. The level of lncRNA OIP5-AS1, miR-410-3p, Wnt7b, β-catenin, c-Myc, cyclin D1, GSK-3β, and SFRP4 mRNA were detected by real-time-qPCR, the expression of Wnt7b, β-catenin, c-Myc, cyclin D1, GSK-3β, and p-GSK-3β (Ser9) protein were detected by immunofluorescence and Western blot.

Results

We found that TSC inhibits the proliferation of RA FLS, TSC significantly reduced lncRNA OIP5-AS1, Wnt7b, β-catenin, c-Myc, cyclin D1, and p-GSK-3β/GSK-3β mRNA/protein expression, whereas the miR-410-3p and SFRP4 mRNA/protein expression levels were significantly upregulated. Our data suggest that TSC can inhibit the excessive proliferation of FLS to treat RA, the mechanism of which may be closely related to regulation of the lncRNA OIP5-AS1/miR-410-3p /Wnt7b signaling axis and the Wnt signaling pathway.

Secretome effect of adipose tissue-derived stem cells cultured two-dimensionally and three-dimensionally in mice with streptozocin induced type 1 diabetes

Aims

To analyze therapeutic potential of the conditioned medium from adipose tissue-derived stem cells (ASC) cultivated in 2D (CM-2D) and 3D (CM-3D) models, in mice with Type 1 diabetes (T1D) induced by streptozotocin.

Main methods

Viability andCD105 expression of 2D and 3D ASC were analyzed by flow cytometry. T1D was induced in mice by multiple injections of streptozocin. On the 28th and 29th days after the first injection of streptozocin, diabetic animals received CM-2D or CM-3D. Pancreatic, CM-2D, and CM-3D cytokines were analyzed by cytometric bead array (CBA) and insulin and PDX-1 were observed and quantified by immunohistochemistry. Apoptosis-related proteins were quantified by Western Blotting.

Key findings

ASC in three-dimensional culture released increased levels of IL-6 and IL-2, while IL-4 was decreased. CM-2D induced pancreatic PDX-1 expression and was able to reduce glycemia in diabetic mice one week after injections but not CM-3D. On the other hand, CM-2D and CM-3D were not able to reverse apoptosis of pancreatic cells in diabetic mice nor to increase insulin expression.

Significance

Together, these results demonstrate that the 3D cell culture secretome was not able to improve diabetes type 1 symptoms at the times observed, while 2D cell secretome improved glycemic levels in T1D mice.

Curcumin and Mesenchymal Stem Cells Ameliorate Ankle, Testis, and Ovary Deleterious Histological Changes in Arthritic Rats via Suppression of Oxidative Stress and Inflammation

Rheumatoid arthritis (RA) is a chronic inflammatory condition, an autoimmune disease that affects the joints, and a multifactorial disease that results from interactions between environmental, genetic, and personal and lifestyle factors. This study was designed to assess the effects of curcumin, bone marrow-derived mesenchymal stem cells (BM-MSCs), and their coadministration on complete Freund's adjuvant- (CFA-) induced arthritis in male and female albino rats. Parameters including swelling of the joint, blood indices of pro-/antioxidant status, cytokines and histopathological examination of joints, and testis and ovary were investigated. RA was induced by a single dose of subcutaneous injection of 0.1 mL CFA into a footpad of the right hind leg of rats. Arthritic rats were treated with curcumin (100 mg/kg b.wt./day) by oral gavage for 21 days and/or treated with three weekly intravenous injections of BM-MSCs (1 × 10⁶ cells/rat/week) in phosphate-buffered saline (PBS). The treatment with curcumin and BM-MSCs singly or together significantly (P < 0.05) improved the bioindicators of oxidative stress and nonenzymatic and enzymatic antioxidants in sera of female rats more than in those of males. Curcumin and BM-MSCs significantly (P < 0.05) improved the elevated TNF-α level and the lowered IL-10 level in the arthritic rats. Furthermore, joint, testis, and ovary histological changes were remarkably amended as a result of treatment with curcumin and BM-MSCs. Thus, it can be concluded that both curcumin and BM-MSCs could have antiarthritic efficacies as well as protective effects to the testes and ovaries which may be mediated via their anti-inflammatory and immunomodulatory potentials as well as oxidative stress modulatory effects.

Mesenchymal Stem Cell-Based Therapy for Rheumatoid Arthritis

Mesenchymal stem cells (MSCs) have great potential to differentiate into various types of cells, including but not limited to, adipocytes, chondrocytes and osteoblasts. In addition to their progenitor characteristics, MSCs hold unique immunomodulatory properties that provide new opportunities in the treatment of autoimmune diseases, and can serve as a promising tool in stem cell-based therapy. Rheumatoid arthritis (RA) is a chronic systemic autoimmune disorder that deteriorates quality and function of the synovium membrane, resulting in chronic inflammation, pain and progressive cartilage and bone destruction. The mechanism of RA pathogenesis is associated with dysregulation of innate and adaptive immunity. Current conventional treatments by steroid drugs, antirheumatic drugs and biological agents are being applied in clinical practice. However, long-term use of these drugs causes side effects, and some RA patients may acquire resistance to these drugs. In this regard, recently investigated MSC-based therapy is considered as a promising approach in RA treatment. In this study, we review conventional and modern treatment approaches, such as MSC-based therapy through the understanding of the link between MSCs and the innate and adaptive immune systems. Moreover, we discuss recent achievements in preclinical and clinical studies as well as various strategies for the enhancement of MSC immunoregulatory properties.

Chronic inflammation-induced senescence impairs immunomodulatory properties of synovial fluid mesenchymal stem cells in rheumatoid arthritis

Background

Although the immunomodulatory properties of mesenchymal stem cells (MSCs) have been highlighted as a new therapy for autoimmune diseases, including rheumatoid arthritis (RA), the disease-specific characteristics of MSCs derived from elderly RA patients are not well understood.

Methods

We established MSCs derived from synovial fluid (SF) from age-matched early (average duration of the disease: 1.7 years) and long-standing (average duration of the disease: 13.8 years) RA patients (E-/L-SF-MSCs) and then analyzed the MSC characteristics such as stemness, proliferation, cellular senescence, in vitro differentiation, and in vivo immunomodulatory properties.

Results

The presence of MSC populations in the SF from RA patients was identified. We found that L-SF-MSCs exhibited impaired proliferation, intensified cellular senescence, reduced immunomodulatory properties, and attenuated anti-arthritic capacity in an RA animal model. In particular, E-SF-MSCs demonstrated cellular senescence progression and attenuated immunomodulatory properties similar to those of L-SF-MSC in an RA joint-mimetic milieu due to hypoxia and pro-inflammatory cytokine exposure. Due to a long-term exposure to the chronic inflammatory milieu, cellular senescence, attenuated immunomodulatory properties, and the loss of anti-arthritic potentials were more often identified in SF-MSCs in a long-term RA than early RA.

Conclusion

We conclude that a chronic RA inflammatory milieu affects the MSC potential. Therefore, this work addresses the importance of understanding MSC characteristics during disease states prior to their application in patients.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02453-z.

Comparative study between human mesenchymal stem cells and etanercept as immunomodulatory agents in rat model of rheumatoid arthritis

To compare human adipose tissue mesenchymal stem cells (AT-MSCs) and etanercept as immunomodulatory agents for collagen-induced arthritis (CIA). CIA was induced by rats' immunization with collagen type II (CII) in complete Freund's adjuvant in days 0 and 7. Before the onset of CIA, prevention group received five doses of AT-MSCS intraperitoneally. After establishment of arthritis, rats received either five doses of AT-MSCs or phosphate-buffered saline (PBS) intraperitoneally or six doses of etanercept subcutaneously. Clinical and histopathological evaluation were performed in all groups; serum levels of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and anti-collagen II were assessed by enzyme-linked immunosorbent assay (ELISA). A total percent of autoreactive T and regulatory T (Treg) cells were quantified using spleen immune histochemical analysis. AT-MSCs were able to delay the onset of CIA, suppress the ongoing clinical and histopathological signs, decrease serum levels of TNF-α and anti-collagen type II, and downregulate the autoreactive T cells as etanercept. AT-MSCs were more potent in Treg cells upregulation, producing high serum levels of IL10. AT-MSCs might have a therapeutic effect in CIA via their potency in immune cell education, representing an effective new promising approach in rheumatoid arthritis in human.

Preclinical Evaluation of a Single Intravenous Infusion of hUC-MSC (BX-U001) in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an inflammatory disease of the joints, which causes severe pain and excessive systemic circulation of harmful inflammatory cytokines. Current treatments are limited, with some patients not responding well, and some experiencing severe and detrimental side effects. Mesenchymal stem cells (MSC) are cell-based therapeutics being evaluated as potent immunomodulators in RA and may provide relief to patients not responding well to drug-based treatments. We evaluated the safety and efficacy of BX-U001 human umbilical cord tissue–derived mesenchymal stem cells (hUC-MSC) to treat RA, in support of a successful investigational new drug application. A collagen-induced arthritis (CIA) mouse model of RA was established in DBA/1 J mice. Mice from the treatment assessment group were given a tail vein infusion of hUC-MSC 24 days after primary RA induction, while control assessment (CA) group mice were given cell-free carrier solution. All animals were evaluated daily for RA symptoms via clinical scoring, blood was taken periodically for cytokine analysis, and mice were dissected at end point for histological analysis. A linear mixed model was used to compare the rate of change among groups. The clinical scores of TA group were significantly reduced compared with CA group (P < 0.01), indicating therapeutic effects. The histological scores of the joints in TA group were significantly lower than those in the CA group (P < 0.05), but had no significant difference compared with Healthy groups (P > 0.05). The concentration of (interleukin) IL-6 in TA group was significantly reduced by 80.0% (P < 0.0001) 2 days after treatment and by 93.4% at the experimental endpoint compared with levels prior to hUC-MSC injection. A single intravenous infusion of hUC-MSC (2 × 10⁶ cells/mouse), to CIA-induced DBA/1 J mice, resulted in significant alleviation of RA symptoms and may provide significant therapeutic benefits in humans.

Driving β2- While Suppressing α-Adrenergic Receptor Activity Suppresses Joint Pathology in Inflammatory Arthritis

Objective

Hypersympathetic activity is prominent in rheumatoid arthritis, and major life stressors precede onset in ~80% of patients. These findings and others support a link between stress, the sympathetic nervous system and disease onset and progression. Here, we extend previous research by evaluating how selective peripherally acting α/β2-adrenergic drugs affect joint destruction in adjuvant-induced arthritis.

Methods

Complete Freund's adjuvant induced inflammatory arthritis in male Lewis rats. Controls received no treatment. Arthritic rats then received vehicle or twice-daily treatment with the α-adrenergic antagonist, phentolamine (0.5 mg/day) and the β2-adrenergic agonist, terbutaline (1200 µg/day, collectively named SH1293) from day (D) of disease onset (D12) through acute (D21) and severe disease (D28). Disease progression was assessed in the hind limbs using dorsoplantar widths, X-ray analysis, micro-computed tomography, and routine histology on D14, D21, and D28 post-immunization.

Results

On D21, SH1293 significantly attenuated arthritis in the hind limbs, based on reduced lymphocytic infiltration, preservation of cartilage, and bone volume. Pannus formation and sympathetic nerve loss were not affected by SH1293. Bone area and osteoclast number revealed high- and low-treatment-responding groups. In high-responding rats, treatment with SH1293 significantly preserved bone area and decreased osteoclast number, data that correlated with drug-mediated joint preservation. SH1293 suppressed abnormal bone formation based on reduced production of osteophytes. On D28, the arthritic sparing effects of SH1293 on lymphocytic infiltration, cartilage and bone sparing were maintained at the expense of bone marrow adipocity. However, sympathetic nerves were retracted from the talocrural joint.

Conclusion and Significance

Our findings support a significant delay in early arthritis progression by treatment with SH1293. Targeting sympathetic neurotransmission may provide a strategy to slow disease progression.

Mesenchymal stem/stromal cells as a valuable source for the treatment of immune-mediated disorders

Over recent years, mesenchymal stem/stromal cells (MSCs) and their potential biomedical applications have received much attention from the global scientific community in an increasing manner. Firstly, MSCs were successfully isolated from human bone marrow (BM), but in the next steps, they were also extracted from other sources, mostly from the umbilical cord (UC) and adipose tissue (AT). The International Society for Cellular Therapy (ISCT) has suggested minimum criteria to identify and characterize MSCs as follows: plastic adherence, surface expression of CD73, D90, CD105 in the lack of expression of CD14, CD34, CD45, and human leucocyte antigen-DR (HLA-DR), and also the capability to differentiate to multiple cell types including adipocyte, chondrocyte, or osteoblast in vitro depends on culture conditions. However, these distinct properties, including self-renewability, multipotency, and easy accessibility are just one side of the coin; another side is their huge secretome which is comprised of hundreds of mediators, cytokines, and signaling molecules and can effectively modulate the inflammatory responses and control the infiltration process that finally leads to a regulated tissue repair/healing or regeneration process. MSC-mediated immunomodulation is a direct result of a harmonic synergy of MSC-released signaling molecules (i.e., mediators, cytokines, and chemokines), the reaction of immune cells and other target cells to those molecules, and also feedback in the MSC-molecule-target cell axis. These features make MSCs a respectable and eligible therapeutic candidate to be evaluated in immune-mediated disorders, such as graft versus host diseases (GVHD), multiple sclerosis (MS), Crohn's disease (CD), and osteoarthritis (OA), and even in immune-dysregulating infectious diseases such as the novel coronavirus disease 2019 (COVID-19). This paper discussed the therapeutic applications of MSC secretome and its biomedical aspects related to immune-mediated conditions. Sources for MSC extraction, their migration and homing properties, therapeutic molecules released by MSCs, and the pathways and molecular mechanisms possibly involved in the exceptional immunoregulatory competence of MSCs were discussed. Besides, the novel discoveries and recent findings on immunomodulatory plasticity of MSCs, clinical applications, and the methods required for their use as an effective therapeutic option in patients with immune-mediated/immune-dysregulating diseases were highlighted.

The Immunomodulatory Effects of Mesenchymal Stem Cells on Regulatory B Cells

The therapeutic potential of mesenchymal stem cells (MSCs) has been investigated in many preclinical and clinical studies. This potential is dominantly based on the immunosuppressive properties of MSCs. Although the therapeutic profiles of MSC transplantation are still not fully characterized, accumulating evidence has revealed that B cells change after MSC infusion, in particular inducing regulatory B cells (Bregs). The immunosuppressive effects of Bregs have been demonstrated, and these cells are being evaluated as new targets for the treatment of inflammatory diseases. MSCs are capable of educating B cells and inducing regulatory B cell production via cell-to-cell contact, soluble factors, and extracellular vesicles (EVs). These cells thus have the potential to complement each other's immunomodulatory functions, and a combined approach may enable synergistic effects for the treatment of immunological diseases. However, compared with investigations regarding other immune cells, investigations into how MSCs specifically regulate Bregs have been superficial and insufficient. In this review, we discuss the current findings related to the immunomodulatory effects of MSCs on regulatory B cells and provide optimal strategies for applications in immune-related disease treatments.

The Use of Collagen-Induced Arthritis Animal Model on Studying Bone Metabolism

CIA is a well-studied animal model of autoimmune arthritis. It resembles rheumatoid arthritis as far as histopathological changes and molecular pathogenesis are concerned. CIA is induced by immunization with collagen type II in susceptible strains. The purpose of this review is to assess the use of CIA animal model on bone metabolism and the potential therapeutic agents that could reverse this effect. A database search from their inception to 2019 was conducted to identify experimental animal studies pertinent to CIA model and bone examination. Studies including ovariectomy or without a direct comparison between control and CIA groups were excluded. Forty-eight articles were considered suitable for inclusion. Imaging techniques, biomechanical analysis, histopathological studies, and molecular biology techniques were employed. A decrease in bone mineral density in CII arthritic animals was established. Bone loss was either periarticular, generalized or both. Although trabecular bone loss was clear, the effect on cortical bone is yet to be determined. The proposed mechanism is an imbalance between bone formation and resorption as a result of osteoclast activation. The signal pathways implicated appear to be the RANKL/RANK/OPG and the Wnt pathway. Many therapeutic targets were investigated with promising results.

Adipose-derived stem cells improve grafted burn wound healing by promoting wound bed blood flow

BACKGROUND

Researchers have explored the use of adipose-derived stem cells (ASCs) as a cell-based therapy to cover wounds in burn patients; however, underlying mechanistic aspects are not completely understood. We hypothesized that ASCs would improve post-burn wound healing after eschar excision and grafting by increasing wound blood flow via induction of angiogenesis-related pathways.

METHODS

To test the hypothesis, we used an ovine burn model. A 5 cm2 full thickness burn wound was induced on each side of the dorsum. After 24 hours, the burned skin was excised and a 2 cm2 patch of autologous donor skin was grafted. The wound sites were randomly allocated to either topical application of 7 million allogeneic ASCs or placebo treatment (phosphate-buffered saline [PBS]). Effects of ASCs culture media was also compared to those of PBS. Wound healing was assessed at one and two weeks following the application of ASCs. Allogeneic ASCs were isolated, cultured and characterized from non-injured healthy sheep. The identity of the ASCs was confirmed by flow cytometry analysis, differentiation into multiple lineages and gene expression via real-time polymerase chain reaction. Wound blood flow, epithelialization, graft size and take and the expression of vascular endothelial growth factor (VEGF) were determined via enzyme-linked immunosorbent assay and Western blot.

RESULTS

Treatment with ASCs accelerated the patch graft growth compared to the control (p < 0.05). Topical application of ASCs significantly increased wound blood flow (p < 0.05). Expression of VEGF was significantly higher in the wounds treated with ASCs compared to control (p < 0.05).

CONCLUSIONS

ASCs accelerated grafted skin growth possibly by increasing the blood flow via angiogenesis induced by a VEGF-dependent pathway.

IL-1β-Mediated Activation of Adipose-Derived Mesenchymal Stromal Cells Results in PMN Reallocation and Enhanced Phagocytosis: A Possible Mechanism for the Reduction of Osteoarthritis Pathology

Background: Injection of adipose-derived mesenchymal stromal cells (ASCs) into murine knee joints after induction of inflammatory collagenase-induced osteoarthritis (CiOA) reduces development of joint pathology. This protection is only achieved when ASCs are applied in early CiOA, which is characterized by synovitis and high S100A8/A9 and IL-1β levels, suggesting that inflammation is a prerequisite for the protective effect of ASCs. Our objective was to gain more insight into the interplay between synovitis and ASC-mediated amelioration of CiOA pathology.

Methods: CiOA was induced by intra-articular collagenase injection. Knee joint sections were stained with hematoxylin/eosin and immunolocalization of polymorphonuclear cells (PMNs) and ASCs was performed using antibodies for NIMP-R14 and CD271, respectively. Chemokine expression induced by IL-1β or S100A8/A9 was assessed with qPCR and Luminex. ASC-PMN co-cultures were analyzed microscopically and with Luminex for inflammatory mediators. Migration of PMNs through transwell membranes toward conditioned medium of non-stimulated ASCs (ASC_NS-CM) or IL-1β-stimulated ASCs (ASC_IL-1β-CM) was examined using flow cytometry. Phagocytic capacity of PMNs was measured with labeled zymosan particles.

Results: Intra-articular saline injection on day 7 of CiOA increased synovitis after 6 h, characterized by PMNs scattered throughout the joint cavity and the synovium. ASC injection resulted in comparable numbers of PMNs which clustered around ASCs in close interaction with the synovial lining. IL-1β-stimulation of ASCs in vitro strongly increased expression of PMN-attracting chemokines CXCL5, CXCL7, and KC, whereas S100A8/A9-stimulation did not. In agreement, the number of clustered PMNs per ASC was significantly increased after 6 h of co-culturing with IL-1β-stimulated ASCs. Also migration of PMNs toward ASC_IL-1β-CM was significantly enhanced (287%) when compared to ASC_NS-CM. Interestingly, association of PMNs with ASCs significantly diminished KC protein release by ASCs (69% lower after 24 h), accompanied by reduced release of S100A8/A9 protein by the PMNs. Moreover, phagocytic capacity of PMNs was strongly enhanced after priming with ASC_IL-1β-CM.

Conclusions: Local application of ASCs in inflamed CiOA knee joints results in clustering of attracted PMNs with ASCs in the synovium, which is likely mediated by IL-1β-induced up-regulation of chemokine release by ASCs. This results in enhanced phagocytic capacity of PMNs, enabling the clearance of debris to attenuate synovitis.

Cannabinoid Receptor 2 Agonist Prevents Local and Systemic Inflammatory Bone Destruction in Rheumatoid Arthritis

Cannabinoid receptor 2 (CB2) has been implicated as an important clinical regulator of inflammation and malignant osteolysis. Here, we observed that CB2 expression was markedly higher in the collagen-induced arthritis (CIA) mice synovium and bone tissues than in the noninflamed synovium and bone tissues. The CB2 selective agonist (JWH133) but not antagonist (SR144528) suppressed CIA in mice without toxic effects, as demonstrated by the decreased synovial hyperplasia, inflammatory responses, cartilage damage, and periarticular and systemic bone destruction. JWH133 treatment decreased the infiltration of pro-inflammatory M1-like macrophages and repolarized macrophages from the M1 to M2 phenotype. Similarly, activation of CB2 increased the expression of anti-inflammatory cytokine interleukin (IL)-10 and reduced the expression of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), IL-1β, and IL-6. In addition, JWH133 treatment attenuated osteoclast formation and osteoclastic bone resorption, and reduced the expression of receptor activators of the nuclear factor-κB (NF-κB) ligand (RANKL), matrix metallopeptidase-9 (MMP-9), tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), and nuclear factor of activated T-cells 1 (NFAT-1) in CIA mice and osteoclast precursors, which were obviously blocked by pretreatment with SR144528. Mechanistically, JWH133 inhibited RANKL-induced NF-κB activation in the osteoclast precursors. We found that JWH133 ameliorates pathologic bone destruction in CIA mice via the inhibition of osteoclastogenesis and modulation of inflammatory responses, thereby highlighting its potential as a treatment for human rheumatoid arthritis. © 2018 American Society for Bone and Mineral Research.

Delivery of oncolytic vaccinia virus by matched allogeneic stem cells overcomes critical innate and adaptive immune barriers

Background

Previous studies have identified IFNγ as an important early barrier to oncolytic viruses including vaccinia. The existing innate and adaptive immune barriers restricting oncolytic virotherapy, however, can be overcome using autologous or allogeneic mesenchymal stem cells as carrier cells with unique immunosuppressive properties.

Methods

To test the ability of mesenchymal stem cells to overcome innate and adaptive immune barriers and to successfully deliver oncolytic vaccinia virus to tumor cells, we performed flow cytometry and virus plaque assay analysis of ex vivo co-cultures of stem cells infected with vaccinia virus in the presence of peripheral blood mononuclear cells from healthy donors. Comparative analysis was performed to establish statistically significant correlations and to evaluate the effect of stem cells on the activity of key immune cell populations.

Results

Here, we demonstrate that adipose-derived stem cells (ADSCs) have the potential to eradicate resistant tumor cells through a combination of potent virus amplification and sensitization of the tumor cells to virus infection. Moreover, the ADSCs demonstrate ability to function as a virus-amplifying Trojan horse in the presence of both autologous and allogeneic human PBMCs, which can be linked to the intrinsic immunosuppressive properties of stem cells and their unique potential to overcome innate and adaptive immune barriers. The clinical application of ready-to-use ex vivo expanded allogeneic stem cell lines, however, appears significantly restricted by patient-specific allogeneic differences associated with the induction of potent anti-stem cell cytotoxic and IFNγ responses. These allogeneic responses originate from both innate (NK)- and adaptive (T)- immune cells and might compromise therapeutic efficacy through direct elimination of the stem cells or the induction of an anti-viral state, which can block the potential of the Trojan horse to amplify and deliver vaccinia virus to the tumor.

Conclusions

Overall, our findings and data indicate the feasibility to establish simple and informative assays that capture critically important patient-specific differences in the immune responses to the virus and stem cells, which allows for proper patient-stem cell matching and enables the effective use of off-the-shelf allogeneic cell-based delivery platforms, thus providing a more practical and commercially viable alternative to the autologous stem cell approach.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1829-z) contains supplementary material, which is available to authorized users.

PDGF enhances the protective effect of adipose stem cell-derived extracellular vesicles in a model of acute hindlimb ischemia

We previously have shown that platelet-derived growth factor (PDGF) modulates the biological activity of extracellular vesicles released by adipose-derived mesenchymal stem cells (ASC-EVs). ASC-EVs may interact with blood and vessel cells by transferring proteins and nucleic acids and regulate their functions. In this study, we investigated immunomodulatory activity and protection from acute hindlimb ischemia of EVs released by PDGF-stimulated ASC (PDGF-EVs). PDGF treatment of ASC changed protein and RNA composition of released EVs by enhancing the expression of anti-inflammatory and immunomodulatory factors. In vitro, control EVs (cEVs) derived from non-stimulated ASC increased the secretion of both the IL-1b, IL-17, IFNγ, TNFα pro-inflammatory factors and the IL-10 anti-inflammatory factor, and enhanced the in vitro peripheral blood mononuclear cell (PBMC) adhesion on endothelium. In contrast, PDGF-EVs enhanced IL-10 secretion and induced TGF-β1 secretion by PBMC. Moreover, PDGF-EVs stimulated the formation of T regulatory cells. In vivo, PDGF-EVs protected muscle tissue from acute ischemia, reduced infiltration of inflammatory cells and increased T regulatory cell infiltration in respect to cEVs. Our results suggest that PDGF-EVs are enriched in anti-inflammatory and immunomodulatory factors and induced in PBMC an enhanced production of IL-10 and TGF-β1 resulting in protection of muscle from acute ischemia in vivo.

Bone erosions in rheumatoid arthritis: recent developments in pathogenesis and therapeutic implications

Bone erosions develop early in the course of rheumatoid arthritis (RA) and deteriorate progressively, causing joint damage and resulting in impaired functional capacity of patients. During the last years, considerable number of studies has increased our understanding of the pathogenetic mechanisms mediating the development of bone erosions in RA. Increased production of RANKL and other cytokines, dysregulation of innate immune mechanisms, autoantibodies specific to RA and alterations of microRNA expression stimulate differentiation and function of osteoclasts, which are responsible for the development of bone erosions. Besides, increased levels of cytokines, overproduction of antagonists of the canonical Wnt signaling pathway and deficient production of bone morphogenetic proteins result in impaired osteoblast differentiation and function, undermining the capacity of bone erosions to repair. Disease-modifying antirheumatic drugs, synthetic or biological, currently used in the treatment of RA, can halt the progression of bone erosions and may even lead to partial repair, although complete repair is unattainable. Targeting pathogenetic mechanisms participating in the erosive process may add to the therapeutic effect of DMARDs and help in the prevention or repair of bone erosions. However, more studies are still needed to confirm whether such therapeutic strategies are effective.

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

IL-3 Differentially Regulates Membrane and Soluble RANKL in Osteoblasts through Metalloproteases and the JAK2/STAT5 Pathway and Improves the RANKL/OPG Ratio in Adult Mice

Bone remodeling comprises balanced activities between osteoclasts and osteoblasts, which is regulated by various factors, including hormones and cytokines. We previously reported that IL-3 inhibits osteoclast differentiation and pathological bone loss. IL-3 also enhances osteoblast differentiation and bone formation from mesenchymal stem cells. However, the role of IL-3 in regulation of osteoblast–osteoclast interactions and underlying mechanisms is not yet delineated. In this study, we investigated the role of IL-3 on the regulation of osteoblast-specific molecules, receptor activator of NF-κB ligand (RANKL), and osteoprotegerin (OPG) that modulate bone homeostasis. We found that IL-3 increases RANKL expression at both the transcriptional and translational levels, and it showed no effect on OPG expression in calvarial osteoblasts. The increased RANKL expression by IL-3 induces mononuclear osteoclasts; however, it does not induce multinuclear osteoclasts. Interestingly, IL-3 decreases soluble RANKL by reducing ectodomain shedding of membrane RANKL through downregulation of metalloproteases mainly a disintegrin and metalloproteinase (ADAM)10, ADAM17, ADAM19, and MMP3. Moreover, IL-3 increases membrane RANKL by activating the JAK2/STAT5 pathway. Furthermore, IL-3 enhances RANKL expression in mesenchymal stem cells of wild-type mice but not in STAT5a knockout mice. Interestingly, IL-3 restores RANKL expression in adult mice by enhancing bone-specific RANKL and decreasing serum RANKL. Furthermore, IL-3 increases the serum OPG level in adult mice. Thus, our results reveal, to our knowledge for the first time, that IL-3 differentially regulates two functional forms of RANKL through metalloproteases and the JAK2/STAT5 pathway, and it helps in restoring the decreased RANKL/OPG ratio in adult mice. Notably, our studies indicate the novel role of IL-3 in regulating bone homeostasis in important skeletal disorders.

Human Gingiva-Derived Mesenchymal Stem Cells Ameliorate Streptozoticin-induced T1DM in mice via Suppression of T effector cells and Up-regulating Treg Subsets

There is yet no cure for type 1 diabetes (T1DM) so far. A significant body of evidence has demonstrated that bone marrow-derived mesenchymal stem cells (BMSCs) showed great potential in controlling T1DM. But there exists much difficulty in using BMSCs as a clinical therapy. We here test whether a new population of mesenchymal stem cells from human gingiva (GMSCs), which has many advantages over BMSCs, can delay or prevent progress of T1DM. GMSCs were adoptively transferred to multiple low-dose streptozotocin (STZ)-induced T1DM. Blood glucose levels and disease severities were analyzed. T cells subsets in blood, spleen and lymph nodes were detected dynamically by flow cytometry. GMSC distribution was dynamically analyzed. We found that infusion of GMSCs but not fibroblast cells significantly controlled blood glucose levels, delayed diabetes onset, ameliorated pathology scores in pancreas, and down-regulated production of IL-17 and IFN-γ in CD4+ and CD8+ T cells in spleens, pancreatic lymph nodes (pLN) and other lymph nodes. GMSCs also up-regulated the levels of CD4+ Treg induced in the periphery. Mechanismly, GMSCs could migrate to pancreas and local lymph node and function through CD39/CD73 pathway to regulate effector T cells. Thus, GMSCs show a potential promise in treating T1DM in the clinic.

Downregulation of miR-106b attenuates inflammatory responses and joint damage in collagen-induced arthritis

Objective

miRNAs are small, signal-strand, non-coding RNAs that function in post-transcriptional regulation. We analysed the in vivo effect of miR-106b (miR-106b-5p) on inflammatory bone loss in CIA mice.

Methods

CIA mice are developed by injecting DAB/1 mice with bovine type II collagen containing Freund's adjuvant and then the in vivo effect of miR-106b is examined. On day 22, mice were given lentiviral negative control, lentiviral-mediated miR-106b mimics or lentiviral-mediated miR-106b inhibitor via orbital injection on a weekly basis. Morphological changes in the ankle joints were assessed via micro-CT and histopathology and cytokine expression levels were examined via immunohistochemical staining, ELISA or flow cytometric analysis. miR-106b and osteoclastic-related gene expression was evaluated via quantitative real-time PCR.

Results

CIA mice were found to have increased miR-106b expression and CIA-associated bone loss and inflammatory infiltration. miR-106b inhibitor treatment markedly decreased arthritis incidence and attenuated bone destruction and histological severity compared with the control group. Moreover, miR-106b inhibitor treatment suppressed RANK ligand (RANKL) expression, increased osteoprotegerin (OPG) expression and reduced the RANKL:OPG ratio in CIA mice. miR-106b inhibition also significantly decreased inflammatory mediator production in joint sections and reduced serum pro-inflammatory cytokine levels when compared with the control group. Additionally, miR-106b inhibition decreased tartrate-resistant acid phosphatase-positive cell numbers and suppressed murine bone marrow macrophage differentiation.

Conclusion

These findings indicate that miR-106b inhibition can ameliorate CIA-associated inflammation and bone destruction and thus may serve as a potential therapeutic for human RA treatment.

Mesenchymal Stem Cells Direct the Immunological Fate of Macrophages

Mesenchymal stem cells (MSC) are multipotent stem cells with a broad well-described immunosuppressive potential. They are able to modulate both the innate and the adaptive immune response. Particularly, MSC are able to regulate the phenotype and function of macrophages that are critical for different biological processes including wound healing, inflammation, pathogenesis of several autoimmune diseases, and tumor growth. These multifunctional roles of macrophages are due to their high plasticity, which enable them to adopt different phenotypes such as a pro-inflammatory M1 and anti-inflammatory M2 phenotype. MSC promote macrophage differentiation toward an M2-like phenotype with a high tissue remodeling potential and anti-inflammatory activity but also a pro-tumorigenic function. MSC regulatory effect on macrophages is mediated through the secretion of different immunomodulatory molecules such as PGE₂, IL1RA, and IL-6. Moreover, the presence of macrophages in damaged tissue and inflammation is essential for MSC to exert their therapeutic function. In this chapter, we discuss how the interplay between macrophages and MSC mutually modulates their phenotypes and functions, orchestrates tissue repair, and controls inflammation during autoimmunity and tumor growth.

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.

Interleukin-3 enhances the migration of human mesenchymal stem cells by regulating expression of CXCR4

BACKGROUND

Mesenchymal stem cells (MSCs) represent an important source for cell therapy in regenerative medicine. MSCs have shown promising results for repair of damaged tissues in various degenerative diseases in animal models and also in human clinical trials. However, little is known about the factors that could enhance the migration and tissue-specific engraftment of exogenously infused MSCs for successful regenerative cell therapy. Previously, we have reported that interleukin-3 (IL-3) prevents bone and cartilage damage in animal models of rheumatoid arthritis and osteoarthritis. Also, IL-3 promotes the differentiation of human MSCs into functional osteoblasts and increases their in-vivo bone regenerative potential in immunocompromised mice. However, the role of IL-3 in migration of MSCs is not yet known. In the present study, we investigated the role of IL-3 in migration of human MSCs under both in-vitro and in-vivo conditions.

METHODS

MSCs isolated from human bone marrow, adipose and gingival tissues were used for in-vitro cell migration, motility and wound healing assays in the presence or absence of IL-3. The effect of IL-3 preconditioning on expression of chemokine receptors and integrins was examined by flow cytometry and real-time PCR. The in-vivo migration of IL-3-preconditioned MSCs was investigated using a subcutaneous matrigel-releasing stromal cell-derived factor-1 alpha (SDF-1α) model in immunocompromised mice.

RESULTS

We observed that human MSCs isolated from all three sources express IL-3 receptor-α (IL-3Rα) both at gene and protein levels. IL-3 significantly enhances in-vitro migration, motility and wound healing abilities of MSCs. Moreover, IL-3 preconditioning upregulates expression of chemokine (C-X-C motif) receptor 4 (CXCR4) on MSCs, which leads to increased migration of cells towards SDF-1α. Furthermore, CXCR4 antagonist AMD3100 decreases the migration of IL-3-treated MSCs towards SDF-1α. Importantly, IL-3 also induces in-vivo migration of MSCs towards subcutaneously implanted matrigel-releasing-SDF-1α in immunocompromised mice.

CONCLUSIONS

The present study demonstrates for the first time that IL-3 has an important role in enhancing the migration of human MSCs through regulation of the CXCR4/SDF-1α axis. These findings suggest a potential role of IL-3 in improving the efficacy of MSCs in regenerative cell therapy.

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.

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.

San-Huang-Xie-Xin-Tang Constituents Exert Drug-Drug Interaction of Mutual Reinforcement at Both Pharmacodynamics and Pharmacokinetic Level: A Review

Inflammatory disorders underlie varieties of human diseases. San-Huang-Xie-xin-Tang (SHXXT), composed with Rhizoma Rhei (Rheum palmatum L.), Rhizoma Coptidis (Coptis chinensis Franch), and Radix Scutellaria (Scutellaria baicalensis Georgi), is a famous formula which has been widely used in the fight against inflammatory abnormalities. Mutual reinforcement is one of the basic theories of traditional Chinese medicine. Here this article reviewed and analyzed the recent research on (1) How the main constituents of SHXXT impact on inflammation-associated signaling pathway molecules. (2) The interaction between the main constituents and efflux pumps or intestinal transporters. The goal of this work was to, (1) Provide evidence to support the theory of mutual reinforcement. (2) Clarify the key targets of SHXXT and suggest which targets need further investigation. (3) Give advice for the clinical use of SHXXT to elevated the absorption of main constituents and eventually promote oral bioavailability. We search literatures in scientific databases with key words of “each main SHXXT constituent,” in combination with “each main inflammatory pathway target molecule” or each main intestinal transporter, respectively. We report the effect of five main constituents on target molecules which lies in three main inflammatory signaling pathways, we as well investigate the interaction between constituents and intestinal transporter. We conclude, (1) The synergistic effect of constituents at both levels confirm the mutual reinforcement theory of TCM as it is proven in this work. (2) The effect of main constituents on downstream targets in nuclear need more further investigation. (3) Drug elevating the absorption of rhein, berberine and baicalein can be employed to promote oral bioavailability of SHXXT.

Bone loss and aggravated autoimmune arthritis in HLA-DRβ1-bearing humanized mice following oral challenge with Porphyromonas gingivalis

Background

The linkage between periodontal disease and rheumatoid arthritis is well established. Commonalities among the two are that both are chronic inflammatory diseases characterized by bone loss, an association with the shared epitope susceptibility allele, and anti-citrullinated protein antibodies.

Methods

To explore immune mechanisms that may connect the two seemingly disparate disorders, we measured host immune responses including T-cell phenotype and anti-citrullinated protein antibody production in human leukocyte antigen (HLA)-DR1 humanized C57BL/6 mice following exposure to the Gram-negative anaerobic periodontal disease pathogen Porphyromonas gingivalis. We measured autoimmune arthritis disease expression in mice exposed to P. gingivalis, and also in arthritis-resistant mice by flow cytometry and multiplex cytokine-linked and enzyme-linked immunosorbent assays. We also measured femoral bone density by microcomputed tomography and systemic cytokine production.

Results

Exposure of the gingiva of DR1 mice to P. gingivalis results in a transient increase in the percentage of Th17 cells, both in peripheral blood and cervical lymph nodes, a burst of systemic cytokine activity, a loss in femoral bone density, and the generation of anti-citrullinated protein antibodies. Importantly, these antibodies are not produced in response to P. gingivalis treatment of wild-type C57BL/6 mice, and P. gingivalis exposure triggered expression of arthritis in arthritis-resistant mice.

Conclusions

Exposure of gingival tissues to P. gingivalis has systemic effects that can result in disease pathology in tissues that are spatially removed from the initial site of infection, providing evidence for systemic effects of this periodontal pathogen. The elicitation of anti-citrullinated protein antibodies in an HLA-DR1-restricted fashion by mice exposed to P. gingivalis provides support for the role of the shared epitope in both periodontal disease and rheumatoid arthritis. The ability of P. gingivalis to induce disease expression in arthritis-resistant mice provides support for the idea that periodontal infection may be able to trigger autoimmunity if other disease-eliciting factors are already present.

Mesenchymal Stem Cells Regulate the Innate and Adaptive Immune Responses Dampening Arthritis Progression

Mesenchymal stem cells (MSCs) are multipotent stem cells that are able to immunomodulate cells from both the innate and the adaptive immune systems promoting an anti-inflammatory environment. During the last decade, MSCs have been intensively studied in vitro and in vivo in experimental animal model of autoimmune and inflammatory disorders. Based on these studies, MSCs are currently widely used for the treatment of autoimmune diseases such as rheumatoid arthritis (RA) characterized by complex deregulation of the immune systems. However, the therapeutic properties of MSCs in arthritis are still controverted. These controversies might be due to the diversity of MSC sources and isolation protocols used, the time, the route and dose of MSC administration, the variety of the mechanisms involved in the MSCs suppressive effects, and the complexity of arthritis pathogenesis. In this review, we discuss the role of the interactions between MSCs and the different immune cells associated with arthritis pathogenesis and the possible means described in the literature that could enhance MSCs therapeutic potential counteracting arthritis development and progression.

Adipose Tissue-Derived Stem Cells in Regenerative Medicine

In regenerative medicine, adult stem cells are the most promising cell types for cell-based therapies. As a new source for multipotent stem cells, human adipose tissue has been introduced. These so called adipose tissue-derived stem cells (ADSCs) are considered to be ideal for application in regenerative therapies. Their main advantage over mesenchymal stem cells derived from other sources, e.g. from bone marrow, is that they can be easily and repeatable harvested using minimally invasive techniques with low morbidity. ADSCs are multipotent and can differentiate into various cell types of the tri-germ lineages, including e.g. osteocytes, adipocytes, neural cells, vascular endothelial cells, cardiomyocytes, pancreatic β-cells, and hepatocytes. Interestingly, ADSCs are characterized by immunosuppressive properties and low immunogenicity. Their secretion of trophic factors enforces the therapeutic and regenerative outcome in a wide range of applications. Taken together, these particular attributes of ADSCs make them highly relevant for clinical applications. Consequently, the therapeutic potential of ADSCs is enormous. Therefore, this review will provide a brief overview of the possible therapeutic applications of ADSCs with regard to their differentiation potential into the tri-germ lineages. Moreover, the relevant advancements made in the field, regulatory aspects as well as other challenges and obstacles will be highlighted.

Adipose-derived stem cells: A novel source of parathyroid cells for treatment of hypoparathyroidism

Hypoparathyroidism is characterized by decreased function of the parathyroid glands with underproduction of parathyroid hormone (PTH), which can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany, and several other symptoms. Severe hypocalcemia is a life-threatening condition. At present, both medical and surgical treatments are offered to improve the blood calcium, but they are not a cure. Adipose-derived stem cells (ADSCs), derived from the adipose tissue, are confirmed to be multipotent with adipogenic, chondrogenic, neurogenic, myogenic and osteogenic capabilities. Our hypothesis is that human ADSCs in culture can be differentiated into parathyroid cells, and used to reconstitute function.

IL-3 Decreases Cartilage Degeneration by Downregulating Matrix Metalloproteinases and Reduces Joint Destruction in Osteoarthritic Mice

Osteoarthritis (OA) is a chronic disease of articular joints that leads to degeneration of both cartilage and subchondral bone. These degenerative changes are further aggravated by proinflammatory cytokines including IL-1β and TNF-α. Previously, we have reported that IL-3, a cytokine secreted by activated T cells, protects cartilage and bone damage in murine models of inflammatory and rheumatoid arthritis. However, how IL-3 protects cartilage degeneration is not yet known. In this study, we investigated the role of IL-3 on cartilage degeneration under both in vitro and in vivo conditions. We found that both mouse and human chondrocytes show strong expression of IL-3R at gene and protein levels. IL-3 increases the expression of mouse chondrocyte-specific genes, Sox9 and collagen type IIa, which were downregulated by IL-1β. Moreover, IL-3 downregulated IL-1β- and TNF-α-induced expression of matrix metalloproteinases in both mouse and human chondrocytes. Interestingly, IL-3 reduces the degeneration of articular cartilage and subchondral bone microarchitecture in a mouse model of human OA. Moreover, IL-3 showed the preventive and therapeutic effects on cartilage degeneration induced by IL-1β in micromass pellet cultures of human mesenchymal stem cells. Thus, to our knowledge, we provide the first evidence that IL-3 has therapeutic potential in amelioration of degeneration of articular cartilage and subchondral bone microarchitecture associated with OA.

Ultrastructural study of mouse adipose-derived stromal cells induced towards osteogenic direction

We investigated the ultrastructural characteristics of mouse adipose-derived stem/stromal cells (ASCs) induced towards osteogenic lineage. ASCs were isolated from adipose tissue of FVB-Cg-Tg(GFPU)5Nagy/J mice and expanded in monolayer culture. Flow cytometry, histochemical staining, and electron microscopy techniques were used to characterize the ASCs with respect to their ability for osteogenic differentiation capacity. Immunophenotypically, ASCs were characterized by high expression of the CD44 and CD90 markers, while the relative content of cells expressing CD45, CD34 and CD117 markers was <2%. In assays of differentiation, the positive response to osteogenic differentiation factors was observed and characterized by deposition of calcium in the extracellular matrix and alkaline phosphatase production. Electron microscopy analysis revealed that undifferentiated ASCs had a rough endoplasmic reticulum with dilated cisterns and elongated mitochondria. At the end of the osteogenic differentiation, the ASCs transformed from their original fibroblast-like appearance to having a polygonal osteoblast-like morphology. Ultrastructurally, these cells were characterized by large euchromatic nucleus and numerous cytoplasm containing elongated mitochondria, a very prominent rough endoplasmic reticulum, Golgi apparatus and intermediate filament bundles. Extracellular matrix vesicles of variable size similar to the calcification nodules were observed among collagen fibrils. Our data provide the ultrastructural basis for further studies on the cellular mechanisms involved in osteogenic differentiation of mouse adipose-derived stem/stromal cells. Microsc. Res. Tech. 79:557-564, 2016. © 2016 Wiley Periodicals, Inc.

Human embryonic stem cell-derived mesenchymal stromal cells ameliorate collagen-induced arthritis by inducing host-derived indoleamine 2,3 dioxygenase

Background

The immunosuppressive and anti-inflammatory properties of mesenchymal stromal cells (MSC) have prompted their therapeutic application in several autoimmune diseases, including rheumatoid arthritis. Adult MSC are finite and their clinical use is restricted by the need for long-term expansion protocols that can lead to genomic instability. Inhibition of Smad2/3 signaling in human pluripotent stem cells (hPSC) provides an infinite source of MSC that match the phenotype and functional properties of adult MSC. Here, we test the therapeutic potential of hPSC-MSC of embryonic origin (embryonic stem cell-derived mesenchymal stromal cells, hESC-MSC) in the experimental model of collagen-induced arthritis (CIA).

Methods

CIA was induced in DBA/1 mice by immunization with type II collagen (CII) in Complete Freund’s Adjuvant (CFA). Mice were treated with either a single dose (10⁶ cells/mouse) of hESC-MSC on the day of immunization (prophylaxis) or with three doses of hESC-MSC every other day starting on the day of arthritis onset (therapy). Arthritis severity was evaluated daily for six weeks and ten days, respectively. Frequency of Treg (FoxP3⁺), Th1 (IFNγ⁺) and Th17 (IL17⁺) CD4⁺ T cells in inguinal lymph nodes (ILN) was quantified by flow cytometry. Serum levels of anti-CII antibodies were determined by ELISA. Detection of hESC-MSC and quantification of murine and human indoleamine 2,3 dioxygenase (IDO1) expression was performed by quantitative real-time PCR. Statistical differences were analyzed by ANOVA and the Mann-Whitney U test.

Results

Administration of hESC-MSC to mice with established arthritis reduced disease severity compared to control-treated mice. Analysis of CD4 T cell populations in treated mice showed an increase in FoxP3⁺ Treg and IFNγ⁺ Th1 cells but not in Th17 cells in the ILN. Anti-CII antibody levels were not affected by treatment. Migration of hESC-MSC to the ILN in treated mice was associated with the induction of murine IDO1.

Conclusion

Treatment with hESC-MSC ameliorates CIA by inducing IFNγ⁺ Th1 cells and IDO1 in the host. Thus, hESC-MSC can provide an infinite cellular source for treatment of rheumatoid arthritis.