Cell Therapy With Mesenchymal Stem Cells Induces an Innate Immune Memory Response That Attenuates Experimental Colitis in the Long Term

Allogeneic bone marrow derived clonal mesenchymal stromal cells in refractory rheumatoid arthritis: a pilot study

AIMS

This phase I trial assessed the safety and potential efficacy of monthly 3 dose intravenous infusion of allogeneic bone marrow-derived clonal mesenchymal stromal cells (BM-cMSCs) in refractory rheumatoid arthritis (RA) patients over 24 weeks.

PATIENTS & METHODS

Six patients with refractory RA received BM-cMSC infusions at one-month intervals over a 24-week period. Safety outcomes included adverse events (AEs) and serious adverse events (SAEs). Clinical efficacy was assessed using the Visual Analog Scale (VAS), Simple and Clinical Disease Activity Indices (SDAI/CDAI), Health Assessment Questionnaire (HAQ), and American College of Rheumatology (ACR) response criteria. Serological makers including: erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), IL-10, IL-17, TNF-α, and Treg/Th17 ratios were measured.

RESULTS

BM-cMSC infusions were well-tolerated, with no SAEs reported. VAS scores improved in three patients, with two achieving sustained pain relief and quality-of-life enhancement. Four patients met ACR20 at week 16, while SDAI and CDAI scores indicated disease activity reduction in three patients. Anti-CCP and RF levels showed variable responses, with some increases not consistently correlating with clinical outcomes. Serological biomarkers showed mixed results; IL-10 increased in five patients, while pro-inflammatory markers TNF-α and IL-17 decreased in the same individuals.

CONCLUSIONS

BM-cMSC therapy demonstrated a favorable safety profile and potential efficacy in managing refractory RA. While preliminary results are promising, further studies with larger cohorts and long-term follow-up are needed to validate these findings and optimize therapeutic strategies.

CLINICAL TRIAL REGISTRATION

IRCT20080728001031N29.

Metformin-mediated effects on mesenchymal stem cells and mechanisms: proliferation, differentiation and aging

Mesenchymal stem cells (MSCs) are a type of pluripotent adult stem cell with strong self-renewal and multi-differentiation abilities. Their excellent biological traits, minimal immunogenicity, and abundant availability have made them the perfect seed cells for treating a wide range of diseases. After more than 60 years of clinical practice, metformin is currently one of the most commonly used hypoglycaemic drugs for type 2 diabetes in clinical practice. In addition, metformin has shown great potential in the treatment of various systemic diseases except for type 2 diabetes in recent years, and the mechanisms are involved with antioxidant stress, anti-inflammatory, and induced autophagy, etc. This article reviews the effects and the underlying mechanisms of metformin on the biological properties, including proliferation, multi-differentiation, and aging, of MSCs in vitro and in vivo with the aim of providing theoretical support for in-depth scientific research and clinical applications in MSCs-mediated disease treatment.

From the updated landscape of the emerging biologics for IBDs treatment to the new delivery systems

Inflammatory bowel diseases (IBDs) treatments have shifted from small-molecular therapeutics to the oncoming biologics. The first-line biologics against the moderate-to-severe IBDs are mainly involved in antibodies against integrins, cytokines and cell adhesion molecules. Besides, other biologics including growth factors, antioxidative enzyme, anti-inflammatory peptides, nucleic acids, stem cells and probiotics have also been explored at preclinical or clinical studies. Biologics with variety of origins have their unique potentials in attenuating immune inflammation or gut mucosa healing. Great advances in use of biologics for IBDs treatments have been archived in recent years. But delivering issues for biologic have also been confronted due to their liable nature. In this review, we will focus on biologics for IBDs treatments in the recent publications; summarize the current landscapes of biologics and their promise to control disease progress. Alternatively, the confronted challenges for delivering biologics will also be analyzed. To combat these drawbacks, some new delivering strategies are provided: firstly, designing the functional materials with high affinity toward biologics; secondly, the delivering vehicle systems to encapsulate the liable biologics; thirdly, the topical adhering delivery systems as enema. To our knowledge, this review is the first study to summarize the updated usage of the oncoming biologics for IBDs, their confronted challenges in term of delivery and the potential combating strategies.

Administration of intestinal mesenchymal stromal cells reduces colitis-associated cancer in C57BL/6J mice modulating the immune response and gut dysbiosis

BACKGROUND

Patients with inflammatory bowel disease (IBD) have a higher risk of developing colitis-associated colorectal cancer (CAC) with poor prognosis. IBD etiology remains undefined but involves environmental factors, genetic predisposition, microbiota imbalance (dysbiosis) and mucosal immune defects. Mesenchymal stromal cell (MSC) injections have shown good efficacy in reducing intestinal inflammation in animal and human studies. However, their effect on tumor growth in CAC and their capacity to restore gut dysbiosis are not clear.

METHODS

The outcome of systemic administrations of in vitro expanded human intestinal MSCs (iMSCs) on tumor growth in vivo was evaluated using the AOM/DSS model of CAC in C57BL/6J mice. Innate and adaptive immune responses in blood, mesenteric lymph nodes (MLNs) and colonic tissue were analyzed by flow cytometry. Intestinal microbiota composition was evaluated by 16S rRNA amplicon sequencing.

RESULTS

iMSCs significantly inhibited colitis and intestinal tumor development, reducing IL-6 and COX-2 expression, and IL-6/STAT3 and PI3K/Akt signaling. iMSCs decreased colonic immune cell infiltration, and partly restored intestinal monocyte homing and differentiation. iMSC administration increased the numbers of Tregs and IFN-γ+CD8+ T cells in the MLNs while decreasing the IL-4+Th2 response. It also ameliorated intestinal dysbiosis in CAC mice, increasing diversity and Bacillota/Bacteroidota ratio, as well as Akkermansia abundance, while reducing Alistipes and Turicibacter, genera associated with inflammation.

CONCLUSION

Administration of iMSCs protects against CAC, ameliorating colitis and partially reverting intestinal dysbiosis, supporting the use of MSCs for the treatment of IBD.

Management of Rheumatoid Arthritis: Possibilities and Challenges of Mesenchymal Stromal/Stem Cell-Based Therapies

Rheumatoid arthritis (RA) is a highly prevalent, chronic, and progressive autoimmune disorder primarily affecting joints and muscles. The associated inflammation, pain, and motor restriction negatively impact patient quality of life (QOL) and can even contribute to premature mortality. Further, conventional treatments such as antiinflammatory drugs are only symptomatic. Substantial progress has been made on elucidating the etiopathology of overt RA, in particular the contributions of innate and adaptive immune system dysfunction to chronic inflammation. Although the precise mechanisms underlying onset and progression remain elusive, the discovery of new drug targets, early diagnosis, and new targeted treatments have greatly improved the prognosis and QOL of patients with RA. However, a sizable proportion of patients develop severe adverse effects, exhibit poor responses, or cannot tolerate long-term use of these drugs, necessitating more effective and safer therapeutic alternatives. Mounting preclinical and clinical evidence suggests that the transplantation of multipotent adult stem cells such as mesenchymal stromal/stem cells is a safe and effective treatment strategy for controlling chronic inflammation and promoting tissue regeneration in patients with intractable diseases, including RA. This review describes the current status of MSC-based therapies for RA as well as the opportunities and challenges to broader clinical application.

MSC therapy ameliorates experimental gouty arthritis hinting an early COX-2 induction

Objective

The specific effect of Adipose-Derived Mesenchymal Stem Cells (Ad-MSC) on acute joint inflammation, where the response mostly depends on innate immunity activation, remains elusive. The pathogenesis of gouty arthritis, characterized by the deposition of monosodium urate (MSU) crystals in the joints, associated to acute flares, has been associated to NLRP3 inflammasome activation and subsequent amplification of the inflammatory response. Our aim was to study the effect of human Ad-MSC administration in the clinical inflammatory response of rabbits after MSU injection, and the molecular mechanisms involved.

Methods

Ad-MSC were administered by intraarterial route shortly after intraarticular MSU crystal injections. Joint and systemic inflammation was sequentially studied, and the mechanisms involved in NLRP3 inflammasome activation, and the synthesis of inflammatory mediators were assessed in the synovial membranes 72h after insult. Ad-MSC and THP-1-derived macrophages stimulated with MSU were co-cultured in transwell system.

Results

A single systemic dose of Ad-MSC accelerated the resolution of local and systemic inflammatory response. In the synovial membrane, Ad-MSC promoted alternatively M2 macrophage presence, inhibiting NLRP3 inflammasome and inducing the production of anti-inflammatory cytokines, such as IL-10 or TGF-β, and decreasing nuclear factor-κB activity. Ad-MSC induced a net anti-inflammatory balance in MSU-stimulated THP-1 cells, with a higher increase in IL-10 and IDO expression than that observed for IL-1β and TNF.

Conclusion

Our in vivo and in vitro results showed that a single systemic dose of Ad-MSC decrease the intensity and duration of the inflammatory response by an early local COX-2 upregulation and PGE2 release. Ad-MSCs suppressed NF-kB activity, NLRP3 inflammasome, and promoted the presence of M2 alternative macrophages in the synovium. Therefore, this therapeutic approach could be considered as a pharmacological alternative in patients with comorbidities that preclude conventional treatment.

Cell-Based Drug Delivery Systems with Innate Homing Capability as a Novel Nanocarrier Platform

Nanoparticle-based drug delivery systems have been designed to treat various diseases. However, many problems remain, such as inadequate tumor targeting and poor therapeutic outcomes. To overcome these obstacles, cell-based drug delivery systems have been developed. Candidates for cell-mediated drug delivery include blood cells, immune cells, and stem cells with innate tumor tropism and low immunogenicity; they act as a disguise to deliver the therapeutic payload. In drug delivery systems, therapeutic agents are encapsulated intracellularly or attached to the surface of the plasma membrane and transported to the desired site. Here, we review the pros and cons of cell-based therapies and discuss their homing mechanisms in the tumor microenvironment. In addition, different strategies to load therapeutic agents inside or on the surface of circulating cells and the current applications for a wide range of disease treatments are summarized.

Assessment of mesenchymal stem/stromal cell-based therapy in K/BxN serum transfer-induced arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial hyperplasia and cartilage/bone destruction with systemic comorbidities. Despite advances in understanding the aetiology of RA and novel biologic drugs, a substantial number of individuals with RA remain intolerant or resistant to these therapies. In this context, mesenchymal stem/stromal cell (MSC)-based therapy has emerged as an innovative therapeutic alternative to address unresolved treatment issues for patients with RA thanks to the immunomodulatory properties of these cells. The majority of preclinical studies in MSC-based therapy have been conducted using the well-known collagen-induced arthritis (CIA) mouse model however due to its low incidence, the mouse strain restriction and the prolonged induction phase of collagen-induced arthritis, alternative experimental models of RA have been developed such as K/BxN serum transfer-induced arthritis (STIA), which mimics many of human RA features. In this study, we evaluate whether the K/BxN STIA model could be used as an alternative model to study the immunomodulatory potential of MSC-based therapy. Unexpectedly, our data suggest that adipose-derived MSC-based therapy is unsuitable for modulating the progression of K/BxN serum-transfer arthritis in mice despite the various experimental parameters tested. Based on the differences in the immune status and monocytic/macrophage balance among the different arthritic models, these results could help to identify the cellular targets of the MSCs and, most importantly to predict the RA patients that will respond positively to MSC-based therapy.

Mesenchymal Stem Cells for the Treatment of Acetic Acid-Induced Ulcerative Colitis in Rats

Background: Ulcerative colitis (UC) is an autoimmune inflammatory bowel disease, characterized by chronic and relapsing inflammation of the intestinal mucosa. Clinical treatments fail to reduce inflammation and induce side effects in nearly 30% of patients. Mesenchymal stem cells (MSCs) are immunomodulatory agents that can encourage tissue repair and regeneration. Aim: To investigate the ability of MSCs to differentiate into enterocytes under the mediation of activin a, fibroblastic growth factor 2, and epidermal growth factors and to study the effect of administering MSCs to rats with acetic acid (AA)-induced UC. Methods: MSCs isolated from the umbilical cord were induced to differentiate into enterocytes. The induced cells were morphologically evaluated by flow cytometry and immunocytochemistry. Forty rats were divided into four groups: control, AA-induced UC, differentiated, and undifferentiated MSC treated groups. The acute UC in rats was induced by 3% AA transrectal administration. Body weight changes, disease activity index (DAI), and histopathological and immunohistochemical CD105 and CD34 staining were recorded. IL-17, IL-10, and TGF- β levels were measured as well. Results: In Both differentiated and undifferentiated MSCs, induced MSCs improved the DAI score and significantly recovered the pathological changes. The favorable effect of MSCs was significantly linked to CD105 overexpression and CD34 low expression. IL-10 and TGF-β levels increased while IL-17 levels decreased. Conclusion: Both differentiated and undifferentiated MSCs showed anti-inflammatory and immunomodulatory effects in our study. Based on our results, MSCs could become potentially useful for regenerative medicine and the clinical treatment of UC.

Mesenchymal stem/stromal cells in the pathogenesis and regenerative therapy of inflammatory bowel diseases

Inflammatory bowel diseases (IBDs) represent a group of chronic inflammatory disorders of the gastrointestinal (GI) tract including ulcerative colitis (UC), Crohn’s disease (CD), and unclassified IBDs. The pathogenesis of IBDs is related to genetic susceptibility, environmental factors, and dysbiosis that can lead to the dysfunction of immune responses and dysregulated homeostasis of local mucosal tissues characterized by severe inflammatory responses and tissue damage in GI tract. To date, extensive studies have indicated that IBDs cannot be completely cured and easy to relapse, thus prompting researchers to find novel and more effective therapeutics for this disease. Due to their potent multipotent differentiation and immunomodulatory capabilities, mesenchymal stem/stromal cells (MSCs) not only play an important role in regulating immune and tissue homeostasis but also display potent therapeutic effects on various inflammatory diseases, including IBDs, in both preclinical and clinical studies. In this review, we present a comprehensive overview on the pathological mechanisms, the currently available therapeutics, particularly, the potential application of MSCs-based regenerative therapy for IBDs.

Biodistribution of 89Zr-oxine-labeled human bone marrow-derived mesenchymal stem cells by micro-PET/computed tomography imaging in Sprague-Dawley rats

PURPOSE

To develop a method for labeling human bone marrow mesenchymal stem cells (hMSCs) with 89Zr-oxine to characterize the biodistribution characteristics of hMSCs in normal Sprague-Dawley (SD) rats in real-time by micro-PET-computed tomography (micro-PET/CT) imaging.

METHODS

89Zr-oxine complex was synthesized from 89Zr-oxalate and 8-hydroxyquinoline (oxine). After hMSCs were labeled with the 89Zr-oxine complex, the radioactivity retention, viability, proliferation, apoptosis, differentiation, morphology, and phenotype of labeled cells were assessed. The biodistribution of 89Zr-oxine-labeled hMSCs in SD rats was tracked in real-time by micro-PET/CT imaging.

RESULTS

The cell labeling efficiency was 52.6 ± 0.01%, and 89Zr-oxine was stably retained in cells (66.7 ± 0.9% retention on 7 days after labeling). Compared with the unlabeled hMSCs, 89Zr-oxine labeling did not affect the biological characteristics of cells. Following intravenous administration in SD rats, labeled hMSCs mainly accumulated in the liver (7.35 ± 1.41% ID/g 10 days after labeling, n = 6) and spleen (8.48 ± 1.20% ID/g 10 days after labeling, n = 6), whereas intravenously injected 89Zr-oxalate mainly accumulated in the bone (4.47 ± 0.35% ID/g 10 days after labeling, n = 3).

CONCLUSION

89Zr-oxine labeling and micro-PET/CT imaging provide a useful and non-invasive method of assessing the biodistribution of cell therapy products in SD rats. The platform provides a foundation for us to further understand the mechanism of action and migration dynamics of cell therapy products.

A long-term anti-inflammation markedly alleviated high-fat diet-induced obesity by repeated administrations of overexpressing IL10 human umbilical cord-derived mesenchymal stromal cells

Objectives

Obesity is a chronic process and could activate various inflammatory responses, which in turn aggravates obesity and related metabolic syndrome. Here we explored whether long-term inhibition of inflammation could successfully alleviate high-fat diet (HFD)-induced obesity.

Methods

We constructed stable overexpressing interleukin 10 (IL10) human umbilical cord-derived mesenchymal stromal cells (HUCMSCs) which repeatedly were applied to obesity mice with HFD feeding to obtain a long-term anti-inflammation based on the prominent anti-inflammation effects of IL10 and immunomodulatery effects of HUCMSCs. Then we monitored the features of obesity including body weight, serum ALT, AST, and lipids. In addition, glucose homeostasis was determined by glucose tolerance and insulin sensitivity tests. The infiltrated macrophages in adipose tissues and hepatic lipid accumulation were detected, and the expressions of adipogenesis and inflammatory genes in adipose tissues were examined by real-time (RT) PCR and western blot analysis.

Results

Compared with HUCMSCs, IL10-HUCMSCs treatment had much better anti-obesity effects including body weight reduction, less hepatic lipids accumulation, lower amount and size of adipocyte, greater glucose tolerance, less systemic insulin resistance, and less adipose tissue inflammation in HFD feeding mice. Finally, IL10-HUCMSCs could decrease the activation of MAPK JNK of adipose tissue induced by HFD. The inhibition of MAPK JNK signal pathway by a small chemical molecule SP600125 in 3T3-L1 cells, a preadipocyte line, reduced the differentiation of adipocytes and lipid droplet accumulation.

Conclusion

A lasting anti-inflammation based on gene modified stem cell therapy is an effective strategy in preventing diet-induced obesity and obesity-related metabolic syndrome.

Anti-Inflammatory Effects Of Calcitriol-Treated Mesenchymal Stem Cells On Experimental Ulcerative Colitis

Objective — Ulcerative colitis is an inflammatory bowel disease usually affecting the innermost lining of the colon and rectum. Both corticosteroids and anti-inflammatory drugs are administrated as medical treatment for UC. However, these drugs, in addition to chemical side effects, impose exorbitant costs on patients. Therefore, extensive studies are underway to find new treatment approaches. This study aims to determine the effect of calcitriol-treated mesenchymal stem cells in the UC treatment. Material and Methods — This experimental study was performed on 50 Wistar rats with inducing ulcerative colitis model by 4% acetic acid. MSCs were isolated from rat bone marrow and proliferated in an appropriate medium. Bone marrow-derived mesenchymal stem cells were injected intraperitoneally. Symptom severity of this disease was evaluated using the factors, such as stool consistency, fecal blood and histopathological study of colon tissue. Furthermore, the levels of myeloperoxidase, nitric oxide and inflammatory cytokines like IL1, IL6 and TNF-α were measured using ELISA technique. Results — The results showed that calcitriol-treated MSCs, significantly reduced the production of inflammatory cytokines including IL-1 (150.22±29.04)(P<0.01), IL-6 (681±56.20)(P<0.01), TNF-α (53.07±11.30)(P<0.01) and significantly decrease in level of NO (12.86±5.65)(P<0.01), MPO (0.175±0.024)(P<0.01) and the destruction of intestinal crypts compared to the control group (P<0.05). Conclusions — It seems that using calcitriol with MSCs has reduced the symptoms of UC in our experimental model. Due to their ease of isolation and expansion, MSCs can be used as an adjunctive therapy to improve the condition of patients with UC colitis.

Roe-inspired stem cell microcapsules for inflammatory bowel disease treatment

Mesenchymal stem cells (MSCs), which exert regulatory effects on various immune cells, have been a promising therapy for inflammatory bowel disease treatment. However, their therapeutic effects are limited by lack of nutritional supply, immune system attack, and low accumulation on the target site. Here, inspired by the natural incubation mechanism of roe, we present immune-isolating, wet-adhesive, and nutrient-rich microcapsules for therapeutic MSCs encapsulation. The adhesive shells were fabricated by ionic cross-linking of alginate and visible curing of epsilon-poly-L-lysine-graft-methacrylamide and dopamine methacrylamide, which encapsulated the liquid core of the MSCs and roe proteins. Due to the core-shell construction of the resultant microcapsules, the MSCs might escape from attack of the immune system while still maintaining immunomodulating functions. In addition, the roe proteins encapsulated in the core phase offered sufficient nutrient supply for MSCs' survival and proliferation. Furthermore, after intraperitoneal transplantation, the wet-adhesive radicals on the shell surface could immobilize the MSCs-encapsulating microcapsules onto the bowel. Based on these features, practical values of the roe-inspired microcapsules with MSCs encapsulation were demonstrated by applying them to treat dextran sulfate sodium (DSS)-induced colitis through increasing residence time, regulating immune imbalance, and relieving disease progression. We believe that the proposed roe-inspired microcapsules with MSCs encapsulation are potential for clinical application.

Improving the Efficacy of Mesenchymal Stem/Stromal-Based Therapy for Treatment of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) consisting of persistent and relapsing inflammatory processes of the intestinal mucosa are caused by genetic, environmental, and commensal microbiota factors. Despite recent advances in clinical treatments aiming to decrease inflammation, nearly 30% of patients treated with biologicals experienced drawbacks including loss of response, while others can develop severe side effects. Hence, novel effective treatments are highly needed. Mesenchymal stem/stromal cell (MSCs) therapy is an innovative therapeutic alternative currently under investigation for IBD. MSCs have the inherent capacity of modulating inflammatory immune responses as well as regenerating damaged tissues and are therefore a prime candidate to use as cell therapy in patients with IBD. At present, MSC-based therapy has been shown preclinically to modulate intestinal inflammation, whilst the safety of MSC-based therapy has been demonstrated in clinical trials. However, the successful results in preclinical studies have not been replicated in clinical trials. In this review, we will summarize the protocols used in preclinical and clinical trials and the novel approaches currently under investigation which aim to increase the beneficial effects of MSC-based therapy for IBD.

The Therapeutic Efficacy of Adipose Tissue-Derived Mesenchymal Stem Cell Conditioned Medium on Experimental Colitis Was Improved by the Serum From Colitis Rats

Adipose derived mesenchymal stem cells (AD-MSCs) have shown therapeutic potential in treatments of inflammatory bowel disease (IBD). Due to the harsh host environment and poor survival of the cells, controversy concerning the homing, proliferation and differentiation of MSCs in lesion tissue still remains. It has been reported that conditioned media from MSCs could improve the colitis, whereas the therapeutic efficiency could be significantly elevated by the stimulation of pro-cytokines. In this study, we pre-treated the adipose derived MSCs with the serum from colitis rats and then the activated conditioned media (CM-AcMSC) were collected. To compare the therapeutic effects of CM-MSC and CM-AcMSC on IBD, we constructed dextran sodium sulphate (DSS)-induced colitis rat models. The colitis was induced in rats by administrating 5% DSS in drinking water for 10 days, and the disease symptoms were recorded daily. The colon histopathological changes were observed by different staining methods (H&E and PAS). The expression levels of MUC2 and tight junctions (TJs) were determined by RT-qPCR. The levels of inflammatory cytokines were analyzed by ELISA and western blot analysis. Our findings suggested that CM-AcMSC was more effective in ameliorating the clinical features and histological damage scores. Treatment with CM-AcMSC significantly increased the expression of MUC2 and TJs and suppressed the production of pro-inflammatory cytokines in colonic tissues of colitis rats. The inhibitory effects of CM-AcMSC on inflammatory responses of colitis rats were mediated by NF-κB signaling pathway. These results suggested that pre-activation of MSCs with serum from colitis rats could promote the production of paracrine factors and improve the therapeutic effects of conditioned medium on colitis rats.

Drug delivery to the inflamed intestinal mucosa - targeting technologies and human cell culture models for better therapies of IBD

Current treatment strategies for inflammatory bowel disease (IBD) seek to alleviate the undesirable symptoms of the disorder. Despite the higher specificity of newer generation therapeutics, e.g. monoclonal antibodies, adverse effects still arise from their interference with non-specific systemic immune cascades. To circumvent such undesirable effects, both conventional and newer therapeutic options can benefit from various targeting strategies. Of course, both the development and the assessment of the efficiency of such targeted delivery systems necessitate the use of suitable in vivo and in vitro models representing relevant pathophysiological manifestations of the disorder. Accordingly, the current review seeks to provide a comprehensive discussion of the available preclinical models with emphasis on human in vitro models of IBD, along with their potentials and limitations. This is followed by an elaboration on the advancements in the field of biology- and nanotechnology-based targeted drug delivery systems and the potential rooms for improvement to facilitate their clinical translation.

Regulation of Inflammatory Cytokine Storms by Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have been widely used in preclinical and clinical trials for various diseases and have shown great potential in the treatment of sepsis and coronavirus disease (COVID-19). Inflammatory factors play vital roles in the pathogenesis of diseases. The interaction between inflammatory factors is extremely complex. Once the dynamics of inflammatory factors are unbalanced, inflammatory responses and cytokine storm syndrome develop, leading to disease exacerbation and even death. Stem cells have become ideal candidates for the treatment of such diseases due to their immunosuppressive and anti-inflammatory properties. However, the mechanisms by which stem cells affect inflammation and immune regulation are still unclear. This article discusses the therapeutic mechanism and potential value of MSCs in the treatment of sepsis and the novel COVID-19, outlines how MSCs mediate innate and acquired immunity at both the cellular and molecular levels, and described the anti-inflammatory mechanisms and related molecular pathways. Finally, we review the safety and efficacy of stem cell therapy in these two diseases at the preclinical and clinical levels.

Mesenchymal stem/stromal cell-based therapy for the treatment of rheumatoid arthritis: An update on preclinical studies

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovial inflammation and progressive joint destruction and is a primary cause of disability worldwide. Despite the existence of numerous anti-rheumatic drugs, a significant number of patients with RA do not respond or are intolerant to current treatments. Mesenchymal stem/stromal cell (MSCs) therapy represents a promising therapeutic tool to treat RA, mainly attributable to the immunomodulatory effects of these cells. This review comprises a comprehensive analysis of the scientific literature related to preclinical studies of MSC-based therapy in RA to analyse key aspects of current protocols as well as novel approaches which aim to improve the efficacy of MSC-based therapy.

Preventive Vaccination with Mesenchymal Stem Cells Protects Mice from Lethal Infection Caused by Herpes Simplex Virus 1

Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) infect almost all organs and tissues, cause genital herpes-the most common sexually transmitted disease-disorders of the central nervous system (CNS), and lead to severe complications in children. Despite the available drugs, the incidence of HSV-1/2 continues to rise. None of the prophylactic vaccine candidates have shown a protective effect in trials nor approval for use in clinical practice. We have investigated the protective properties of mesenchymal stem cells (MSC) isolated from the bone marrow of mice. A comparative analysis of the protective response to the introduction of primary and modified MSCs (mMSC) was carried out using the plasmid containing gene of the HSV and an inactivated virus in a model of lethal HSV-1 infection in mice. mMSCs were obtained by transfection of the Us6 gene encoding glycoprotein D (gD) of the HSV, the plasmid contained the same gene. After twofold immunization with primary MSCs, the formation of antibodies interacting with the viral antigen (according to enzyme immunoassay data) and neutralizing the infectious activity of HSV-1 in the reaction of biological neutralization was observed in the peripheral blood of mice. In addition, the introduction of primary MSCs induced the production of interferon gamma (INF-γ) which is detected in the peripheral blood of mice. After infection with HSV-1, the immunized mice showed significantly increased titers of virus-specific antibodies, an increased level of IFNγ, and were completely protected from lethal HSV-1 infection. The protective effect of the other three immunogens was lower and did not exceed 50-65%. Considering the wide availability of MSCs, the proven safety of intravenous administration, and the results obtained in this work on the ability to induce innate, adaptive and protective immunity to HSV-1, MSCs can be considered a promising basis for the development of new cellular vaccines for the prevention of herpesvirus and other viral infections.

Therapeutic Effect of Mesenchymal Stem Cells in Ulcerative Colitis: A Review on Achievements and Challenges

The worldwide epidemiology of inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), still shows an increasing trend in Asia and Iran. Despite an improvement in the treatment landscape focused on symptomatic control, long-term colectomies have not decreased over the last 10-year period. Thus, novel therapies are urgently needed in clinics to supplement the existing treatments. Mesenchymal stem cells (MSCs) are multipotent adult stem cells with immunosuppressive effects, targeting IBD as a new treatment strategy. They have recently received global attention for their use in cell transplantation due to their easy expansion and wide range of activities to be engrafted, and because they are home to the mucosa of the intestine. Moreover, MSCs are able to differentiate into epithelial and other cells that can directly promote repair in the mucosal damages in UC. It seems that there is a need to deepen our understanding to target MSCs as a promising treatment option for UC patients who are refractory to conventional therapies. Here, we overviewed the therapeutic effects of MSCs in UC and discussed the achievements and challenges in the cell transplantation of UC.

Involvement of Mesenchymal Stem Cells in Oral Mucosal Bacterial Immunotherapy

Recent clinical observations indicate that bacterial vaccines induce cross-protection against infections produced by different microorganisms. MV130, a polyvalent bacterial sublingual preparation designed to prevent recurrent respiratory infectious diseases, reduces the infection rate in patients with recurrent respiratory tract infections. On the other hand, mesenchymal stem cells (MSCs) are key cell components that contribute to the maintenance of tissue homeostasis and exert both immunostimulatory and immunosuppressive functions. Herein, we study the effects of MV130 in human MSC functionality as a potential mechanism that contributes to its clinical benefits. We provide evidence that during MV130 sublingual immunization of mice, resident oral mucosa MSCs can take up MV130 components and their numbers remain unchanged after vaccination, in contrast to granulocytes that are recruited from extramucosal tissues. MSCs treated in vitro with MV130 show an increased viability without affecting their differentiation potential. In the short-term, MSC treatment with MV130 induces higher leukocyte recruitment and T cell expansion. In contrast, once T-cell activation is initiated, MV130 stimulation induces an up-regulated expression of immunosuppressor factors in MSCs. Accordingly, MV130-primed MSCs reduce T lymphocyte proliferation, induce the differentiation of dendritic cells with immunosuppressive features and favor M2-like macrophage polarization, thus counterbalancing the immune response. In addition, MSCs trained with MV130 undergo functional changes, enhancing their immunomodulatory response to a secondary stimulus. Finally, we show that MSCs are able to uptake, process and retain a reservoir of the TLR ligands derived from MV130 digestion which can be subsequently transferred to dendritic cells, an additional feature that also may be associated to trained immunity.

Autophagy controls mesenchymal stem cell therapy in psychological stress colitis mice

Mesenchymal stem cell transplantation (MSCT) has been applied to treat a variety of autoimmune and inflammatory diseases. Psychosocial stress can aggravate disease progression in chronic inflammatory patients. Whether psychological stress affects MSCT is largely unknown. In this study we show that psychological stress attenuates therapeutic effects of MSCT in a DSS-induced colitis mouse model by elevating the levels of exosomal Mir7k/mmu-let-7 k (microRNA 7 k) in circulation. Mechanistically, Mir7k inhibits STAT3 pathway in donor MSCs, leading to upregulated expression of BECN1 (beclin 1, autophagy related) and, thus, activation of macroautophagy/autophagy. Inhibition of autophagy by blocking Mir7k or activating STAT3 signaling can restore MSCT-mediated therapy in psychologically stressed colitis mice. Our study identifies a previously unknown role of autophagy in regulating MSCT therapy via exosomal miRNA Mir7k.Abbreviations: BafA1: bafilomycin A₁; BECN1: beclin 1, autophagy related; DAI: disease activity index; DAPI: 4',6-diamidino-2-phenylindole; DSS: dextran sulfate sodium; GFP: green fluorescent protein; HAI: histological activity index; IFNG/IFN-γ: interferon gamma; IL10: interleukin 10; IL1RN/IL-1Rra: interleukin 1 receptor antagonist; KD: knockdown; miRNA: microRNA; MSCs: mesenchymal stem cells; MSCT: mesenchymal stem cell transplantation; NTA: nanoparticle tracking analysis; PGE2: prostaglandin E2; SD: standard deviation; siRNA: small-interfering RNA; STAT3: signal transducer and activator of transcription 3; TEM: transmission electron microscopy; TGFB1/TGF-β1: transforming growth factor, beta 1; Th17 cell: T helper cell 17; TNF/TNF-α: tumor necrosis factor; TNFAIP6/TSG6: tumor necrosis factor alpha induced protein 6; Tregs: regulatory T cells.

Mesenchymal Stem/Stromal Cells for Rheumatoid Arthritis Treatment: An Update on Clinical Applications

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that affects the lining of the synovial joints leading to stiffness, pain, inflammation, loss of mobility, and erosion of joints. Its pathogenesis is related to aberrant immune responses against the synovium. Dysfunction of innate and adaptive immunity, including dysregulated cytokine networks and immune complex-mediated complement activation, are involved in the progression of RA. At present, drug treatments, including corticosteroids, antirheumatic drugs, and biological agents, are used in order to modulate the altered immune responses. Chronic use of these drugs may cause adverse effects to a significant number of RA patients. Additionally, some RA patients are resistant to these therapies. In recent years, mesenchymal stem/stromal cell (MSCs)-based therapies have been largely proposed as a novel and promising stem cell therapeutic approach in the treatment of RA. MSCs are multipotent progenitor cells that have immunomodulatory properties and can be obtained and expanded easily. Today, nearly one hundred studies in preclinical models of RA have shown promising trends for clinical application. Proof-of-concept clinical studies have demonstrated satisfactory safety profile of MSC therapy in RA patients. The present review discusses MSC-based therapy approaches with a focus on published clinical data, as well as on clinical trials, for treatment of RA that are currently underway.