Mesenchymal stromal cells infusions improve refractory chronic graft versus host disease through an increase of CD5+ regulatory B cells producing interleukin 10

Mesenchymal stromal cell therapy: Progress to date and future outlook

In clinical trials, mesenchymal stromal/stem cells (MSCs) have consistently demonstrated safety. However, demonstration of efficacy has been inconsistent and many MSC trials have failed to meet their efficacy endpoint. This disappointing reality is reflected by the limited number MSC therapies approved by regulatory agencies, despite the large number of MSC trials registered on clinicaltrials.gov. Notably, there has been a recent approval of an MSC therapy for pediatric graft-vs.-host disease in the United States, marking the first MSC therapy approved by the U.S. Food and Drug Administration. This review provides a background of the history and potential therapeutic value of MSCs, an overview of MSC products with regulatory approval, and a summary of registered MSC trials. It concludes with a discussion on current and ongoing challenges and questions surrounding MSC therapy that remains to be resolved before becoming available for routine clinical use outside of clinical trials.

Ex vivo-generated human CD1c+ regulatory B cells by a chemically defined system suppress immune responses and alleviate graft-versus-host disease

IL-10+ regulatory B cells (Bregs) show great promise in treating graft-versus-host disease (GVHD), a life-threatening complication of post-hematopoietic stem cell transplantation. However, obtaining high-quality human IL-10+ Bregs in vitro remains a challenge due to the lack of unique specific markers and the triggering of pro-inflammatory cytokine expression. Here, by uncovering the critical signaling pathways in Breg induction by mesenchymal stromal cells (MSCs), we first established an efficient Breg induction system based on MSCs and GSK-3β blockage (CHIR-99021), which had a robust capacity to induce IL-10+ Bregs while suppressing tumor necrosis factor α (TNF-α) expression. Furthermore, these Breg populations could be identified and enriched by CD1c+. Mechanistically, MSCs induced the expansion of Bregs through the PKA-mediated phosphorylation of cAMP response element-binding protein (CREB). Thus, we developed a chemically defined inducing protocol by PKA-CREB agonist, instead of MSCs, which can also effectively induce CD1c+ Bregs with lower TNF-α expression. Importantly, induced CD1c+ Bregs suppressed the proliferation of peripheral blood mononuclear cells and the inflammatory cytokine secretion of T cells. When adoptively transferred into a humanized mouse model of GVHD, induced CD1c+ Bregs effectively alleviated GVHD. Overall, we established an efficient ex vivo induction system for human Bregs, which has implications for developing novel Bregs-based therapies for GVHD.

Posttransplantation cyclophosphamide mediates effective reconstitution of memory B cells after allogeneic hematopoietic cell transplantation

OBJECTIVES

Impaired B-cell reconstitution after allogeneic hematopoietic cell transplantation (allo-HCT) contributes to the pathogenesis of chronic graft-versus-host disease (cGVHD). Therefore, methods to consistently achieve effective B cell lymphogenesis are required. We assessed the long-term effects of posttransplantation cyclophosphamide (PTCy) use on immune reconstitution in clinical settings, an emerging strategy to suppress allogeneic immunological inflammation early after allo-HCT and prevent subsequent GVHD.

METHODS

We comprehensively analyzed peripheral immune cell subsets and measured serum immunoglobulin G (IgG) or cytokine levels in 39 patients who survived for >1 year after allo-HCT.

RESULTS

The absolute counts of B1 and IgM memory B cells were significantly lower in patients with severe cGVHD than in those without. The absolute count and percentage (among total CD19+ B cells) of switched memory B cells and serum IgG levels were significantly higher in patients transplanted with PTCy than in those transplanted with conventional GVHD prophylaxis. Interestingly, increased percentages of switched memory B cells and serum IgG levels were observed only in patients transplanted with PTCy and not in those transplanted with umbilical cord blood.

CONCLUSIONS

PTCy administration can mediate favorable memory B-cell reconstitution long after allo-HCT and may therefore suppress cGVHD.

The NLRP3 molecule influences the therapeutic effects of mesenchymal stem cells through Glut1-mediated energy metabolic reprogramming

INTRODUCTION

Numerous studies demonstrated that NLRP3 has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Mesenchymal stem cells (MSCs) regulated the NLRP3 inflammasome, which has emerged as a novel therapeutic approach for treating IBD.

OBJECTIVES

The exact role of NLRP3 in regulating MSCs' function is unclear. Our study aimed to explore how NLRP3 affects the therapeutic effects of MSCs in colitis.

METHODS

We extracted MSCs from the bone marrow of C57BL/6 mice and Nlrp3 KO mice, and identified them using differentiation assays and flow cytometry. In vitro, Both WT MSCs and Nlrp3 KO MSCs were stimulated with inflammatory factor Lipopolysaccharide (LPS), and only WT MSCs were stimulated with varying concentrations of the NLRP3 inhibitor MCC950, then, quantified IL-10 levels in the supernatant. RNA-seq was performed to examine gene expression patterns and Seahorse was used to assess oxidative phosphorylation (OXPHOS) and glycolysis levels. Western blot was used to evaluate protein expression. In vivo, we treated DSS-induced colitis with either WT or Nlrp3 KO MSCs, monitoring weight, measuring colon length, and further evaluation. We also treated DSS-induced colitis with pretreated MSCs (BAY876, oe-Glut1, or oe-NLRP3), following the same experimental procedures as described above.

RESULTS

Our results demonstrate that Nlrp3 deletion did not affect MSC phenotypes, but rather promoted osteogenic differentiation. However, the absence of Nlrp3 reduced IL-10 production in MSCs in the presence of LPS, leading to impaired protection on DSS-induced colitis. Conversely, overexpression of NLRP3 promotes the production of IL-10, enhancing therapeutic effects. Further investigation revealed that Nlrp3 deficiency downregulated Glut1 expression and glycolysis activation in MSCs, resulting in decreased IL-10 production. Notably, overexpressing Glut1 in Nlrp3 KO MSCs restored their therapeutic effect that was previously dampened due to Nlrp3 deletion.

CONCLUSION

Our findings demonstrate that NLRP3 heightens the therapeutic effects of MSC treatment on DSS-induced colitis.

Mesenchymal stem cell therapy for liver transplantation: clinical progress and immunomodulatory properties

Although liver transplantation (LT) is an effective strategy for end-stage liver diseases, the shortage of donor organs and the immune rejection hinder its widespread implementation in clinical practice. Mesenchymal stem cells (MSCs) transplantation offers a promising approach for patients undergoing liver transplantation due to their immune regulatory capabilities, hepatic protection properties, and multidirectional differentiation potential. In this review, we summarize the potential applications of MSCs transplantation in various LT scenarios. MSCs transplantation has demonstrated effectiveness in alleviating hepatic ischemia-reperfusion injury, enhancing the viability of liver grafts, preventing acute graft-versus-host disease, and promoting liver regeneration in split LT therapy. We also discuss the clinical progress, and explore the immunomodulatory functions of MSCs in response to both adaptive and innate immune responses. Furthermore, we emphasize the interactions between MSCs and different immune cells, including T cells, B cells, plasma cells, natural killer cells, dendritic cells, Kupffer cells, and neutrophils, to provide new insights into the immunomodulatory properties of MSCs in adoptive cell therapy.

Oral Chronic Graft-Versus-Host Disease: Pathogenesis, Diagnosis, Current Treatment, and Emerging Therapies

Chronic graft-versus-host disease (cGvHD) is a multisystem disorder that occurs in recipients of allogeneic hematopoietic (alloHCT) stem cell transplants and is characterized by both inflammatory and fibrotic manifestations. It begins with the recognition of host tissues by the non-self (allogeneic) graft and progresses to tissue inflammation, organ dysfunction and fibrosis throughout the body. Oral cavity manifestations of cGVHD include mucosal features, salivary gland dysfunction and fibrosis. This review synthesizes current knowledge on the pathogenesis, diagnosis and management of oral cGVHD, with a focus on emerging trends and novel therapeutics. Data from various clinical studies and expert consensus are integrated to provide a comprehensive overview.

[Chinese expert consensus on the diagnosis and treatment of chronic graft-versus-host disease (2024)]

Chronic graft-versus-host disease (cGVHD) is a common and severe complication following allogeneic hematopoietic stem cell transplantation, which significantly impacts patients' survival and quality of life. In recent years, notable progress has been made in the diagnosis, prevention, and treatment of cGVHD, driven by the emergence of novel therapies such as targeted drugs and the advancement of clinical research. This consensus, based on the latest developments in cGVHD research and growing data from evidence-based medicine, has been revised and updated from the "Chinese consensus on the diagnosis and management of chronic graft-versus-host disease (2021)" to better guide clinical practice.

Umbilical Cord Blood-Derived Cells Can Reconstruct Hematopoiesis in an Aplastic Anemia Animal Model

Objectives

To explore the efficacy and the mechanism of the umbilical cord-derived cells combined with cyclosporine A (CsA) in treating aplastic anemia (AA) in mice.

Methods

Immune-mediated AA model mice were treated with CsA + UC mesenchymal stem cells (UC-MSC), CsA + umbilical cord blood regulatory T cells (UCB-Treg), UC-MSC, UCB-Treg, CsA alone, or blank control, respectively (n = 9 mice/group). CsA and the cell infusion was administered on d0. Routine peripheral blood testing was performed once weekly; bone marrow colony culture, bone marrow cell flow cytometry, peripheral blood T cell subsets, and serum inflammatory cytokines tests were performed on d14. Transcriptome sequencing was performed for cells from CsA + UC-MSC, CsA + UCB-Treg, and CsA groups to detect the possible related genes. Gene function cluster and signal pathway enrichment analysis were also performed.

Results

Blank control mice died due to pancytopenia within 21 days, whereas mice in other groups survived for >28 days. On d14, the CsA + UC-MSC and CsA + UCB-Treg groups had higher white blood cell (WBC) counts than the other groups (p < 0.05), along with higher burst-forming unit (BFU) and colony-forming unit-granulocyte, macrophage (CFU-GM) counts (p < 0.01). The CsA + UC-MSC group had the highest BFU count (p < 0.01). The CsA + UC-MSC and CsA + UCB-Treg groups exhibited the highest bone marrow CD34+ cell proportion (9.68% ± 1.35% and 8.17% ± 0.53%, respectively; p < 0.01). Tumor necrosis factor (TNF)-α and interleukin (IL)-2 levels in the CsA + UC-MSC group (p < 0.05) and TNF-α, interleukin-2, and interferon (INF)-γ levels in the CsA + UC-Treg group (p < 0.01) were lower than those in the CsA group. Compared with CsA treatment, CsA + UC-MSC significantly downregulated the histone methylation pathway (p < 0.05), whereas CsA + UCB-Treg significantly upregulated energy metabolism processes (p < 0.05). Treatment with CsA + UC-MSC upregulated superoxide dismutase activity compared with CsA + UCB-Treg treatment.

Conclusions

Adding UC-MSC or UCB-Treg to CsA markedly enhanced the reconstruction of hematopoiesis in AA mice, with UC-MSC eliciting greater efficiency than UCB-Treg. Accordingly, the addition of these cells could further improve immune abnormalities.

Comprehensive Review of COVID-19: Epidemiology, Pathogenesis, Advancement in Diagnostic and Detection Techniques, and Post-Pandemic Treatment Strategies

At present, COVID-19 remains a public health concern due to the ongoing evolution of SARS-CoV-2 and its prevalence in particular countries. This paper provides an updated overview of the epidemiology and pathogenesis of COVID-19, with a focus on the emergence of SARS-CoV-2 variants and the phenomenon known as 'long COVID'. Meanwhile, diagnostic and detection advances will be mentioned. Though many inventions have been made to combat the COVID-19 pandemic, some outstanding ones include multiplex RT-PCR, which can be used for accurate diagnosis of SARS-CoV-2 infection. ELISA-based antigen tests also appear to be potential diagnostic tools to be available in the future. This paper also discusses current treatments, vaccination strategies, as well as emerging cell-based therapies for SARS-CoV-2 infection. The ongoing evolution of SARS-CoV-2 underscores the necessity for us to continuously update scientific understanding and treatments for it.

CCR5-overexpressing mesenchymal stem cells protect against experimental autoimmune uveitis: insights from single-cell transcriptome analysis

Autoimmune uveitis is a leading cause of severe vision loss, and animal models provide unique opportunities for studying its pathogenesis and therapeutic strategies. Here we employ scRNA-seq, RNA-seq and various molecular and cellular approaches to characterize mouse models of classical experimental autoimmune uveitis (EAU), revealing that EAU causes broad retinal neuron degeneration and marker downregulation, and that Müller glia may act as antigen-presenting cells. Moreover, EAU immune response is primarily driven by Th1 cells, and results in dramatic upregulation of CC chemokines, especially CCL5, in the EAU retina. Accordingly, overexpression of CCR5, a CCL5 receptor, in mesenchymal stem cells (MSCs) enhances their homing capacity and improves their immunomodulatory outcomes in preventing EAU, by reducing infiltrating T cells and activated microglia and suppressing Nlrp3 inflammasome activation. Taken together, our data not only provide valuable insights into the molecular characteristics of EAU but also open an avenue for innovative MSC-based therapy.

miRNA-148a-containing GMSC-derived EVs modulate Treg/Th17 balance via IKKB/NF-κB pathway and treat a rheumatoid arthritis model

Mesenchymal stem cells (MSCs) have demonstrated potent immunomodulatory properties that have shown promise in the treatment of autoimmune diseases, including rheumatoid arthritis (RA). However, the inherent heterogeneity of MSCs triggered conflicting therapeutic outcomes, raising safety concerns and limiting their clinical application. This study aimed to investigate the potential of extracellular vesicles derived from human gingival mesenchymal stem cells (GMSC-EVs) as a therapeutic strategy for RA. Through in vivo experiments using an experimental RA model, our results demonstrate that GMSC-EVs selectively homed to inflamed joints and recovered Treg and Th17 cell balance, resulting in the reduction of arthritis progression. Our investigations also uncovered miR-148a-3p as a critical contributor to the Treg/Th17 balance modulation via IKKB/NF-κB signaling orchestrated by GMSC-EVs, which was subsequently validated in a model of human xenograft versus host disease (xGvHD). Furthermore, we successfully developed a humanized animal model by utilizing synovial fibroblasts obtained from patients with RA (RASFs). We found that GMSC-EVs impeded the invasiveness of RASFs and minimized cartilage destruction, indicating their potential therapeutic efficacy in the context of patients with RA. Overall, the unique characteristics - including reduced immunogenicity, simplified administration, and inherent ability to target inflamed tissues - position GMSC-EVs as a viable alternative for RA and other autoimmune diseases.

Immunological effects of human decidual mesenchymal stem cells in spontaneous and recurrent abortions

The aim of this study was to evaluate the immunological activities of human decidual mesenchymal stem cells (MSCs) on proliferation, apoptosis and percentage of regulatory T cells (Treg) in abortions and to investigate whether these activities differ in spontaneous abortions (SA) and recurrent abortions (RA). This prospective cohort study included women who had a first-trimester abortion between 2019 and 2022. Women with uterine anomaly, endocrinological disease, known autoimmune or thrombophilic disease, and fetal chromosomal abnormality in abortion material were excluded. Decidual MSCs isolated from abortion materials were classified as spontaneous abortion-MSCs (SA-MSCs) and recurrent abortion-MSCs (RA-MSCs). Peripheral blood mononuclear cells were isolated from venous blood and co-cultured with SA-MSCs and RA-MSCs. The effects of MSCs on proliferation and apoptosis of lymphocytes, and Tregs levels were compared between SA-MSCs and RA-MSCs groups. Thirty cases (15 SA-MSCs and 15 RA-MSCs) were included in the study. The presence of MSC in co-cultures increased percentage of Treg cells while reducing proliferation and apoptosis compared to those without MSCs (p < 0.0001, p < 0.0001 and p < 0.0001). The increase in percentage of Treg cells and the reduction in apoptosis were significantly lower in the RA-MSCs group compared to the SA-MSCs group (p < 0.0001 and p < 0.001, respectively). Although the proliferation reducing effect of the presence of MSCs was lower in the RA-MSCs group compared to the SA-MSCs group, the difference was not significant (p = 0.07). MSCs contribute to maternal immunotolerance to semi-allogeneic fetus by suppressing proliferation and apoptosis, and increasing percentage of Treg cells. However, the immunoregulatory effects of MSCs are lower in RA compared to SA.

Mesenchymal stromal cells alleviate depressive and anxiety-like behaviors via a lung vagal-to-brain axis in male mice

Major depressive disorder (MDD) is one of the most common and disabling mental disorders, and current strategies remain inadequate. Although mesenchymal stromal cells (MSCs) have shown beneficial effects in experimental models of depression, underlying mechanisms remain elusive. Here, using murine depression models, we demonstrated that MSCs could alleviate depressive and anxiety-like behaviors not due to a reduction in proinflammatory cytokines, but rather activation of dorsal raphe nucleus (DRN) 5-hydroxytryptamine (5-HT) neurons. Mechanistically, peripheral delivery of MSCs activated pulmonary innervating vagal sensory neurons, which projected to the nucleus tractus solitarius, inducing the release of 5-HT in DRN. Furthermore, MSC-secreted brain-derived neurotrophic factor activated lung sensory neurons through tropomyosin receptor kinase B (TrkB), and inhalation of a TrkB agonist also achieved significant therapeutic effects in male mice. This study reveals a role of peripheral MSCs in regulating central nervous system function and demonstrates a potential "lung vagal-to-brain axis" strategy for MDD.

Stem cell-based therapy for COVID-19

While The World Health Organization (WHO) has announced that COVID-19 is no longer a public health emergency of international concern(PHEIC), the risk of reinfection and new emerging variants still makes it crucial to study and work towards the prevention of COVID-19. Stem cell and stem cell-like derivatives have shown some promising results in clinical trials and preclinical studies as an alternative treatment option for the pulmonary illnesses caused by the COVID-19 and can be used as a potential vaccine. In this review, we will systematically summarize the pathophysiological process and potential mechanisms underlying stem cell-based therapy in COVID-19, and the registered COVID-19 clinical trials, and engineered extracellular vesicle as a potential vaccine for preventing COVID-19.

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.

Mesenchymal stromal cells and their small extracellular vesicles in allergic diseases: From immunomodulation to therapy

Mesenchymal stromal cells (MSCs) have long been considered a potential tool for treatment of allergic inflammatory diseases, owing to their immunomodulatory characteristics. In recent decades, the medical utility of MSCs has been evaluated both in vitro and in vivo, providing a foundation for therapeutic applications. However, the existing limitations of MSC therapy indicate the necessity for novel therapies. Notably, small extracellular vesicles (sEV) derived from MSCs have emerged rapidly as candidates instead of their parental cells. The acquisition of abundant and scalable MSC-sEV is an obstacle for clinical applications. The potential application of MSC-sEV in allergic diseases has attracted increasing attention from researchers. By carrying biological microRNAs or active proteins, MSC-sEV can modulate the function of various innate and adaptive immune cells. In this review, we summarise the recent advances in the immunomodulatory properties of MSCs in allergic diseases, the cellular sources of MSC-sEV, and the methods for obtaining high-quality human MSC-sEV. In addition, we discuss the immunoregulatory capacity of MSCs and MSC-sEV for the treatment of asthma, atopic dermatitis, and allergic rhinitis, with a special emphasis on their immunoregulatory effects and the underlying mechanisms of immune cell modulation.

hMSCs treatment attenuates murine herpesvirus-68 (MHV-68) pneumonia through altering innate immune response via ROS/NLRP3 signaling pathway

Immunocompromised individuals are particularly vulnerable to viral infections and reactivation, especially endogenous herpes viruses such as Epstein-Barr virus (EBV), a member of oncogenic gamma-herpesviruses, which are commonly linked to pneumonia and consequently significant morbidity and mortality. In the study of human and animal oncogenic gammaherpesviruses, the murine gamma-herpesviruses-68 (MHV-68) model has been applied, as it can induce pneumonia in immunocompromised mice. Mesenchymal stem cell (MSC) treatment has demonstrated therapeutic potential for pneumonia, as well as other forms of acute lung injury, in preclinical models. In this study, we aim to investigate the therapeutic efficacy and underlying mechanisms of human bone marrow-derived MSC (hMSC) on MHV-68-induced pneumonia. We found that intravenous administration of hMSCs significantly reduced lung damages, diminished inflammatory mediators and somehow inhibited MHV-68 replication. Furthermore, hMSCs treatment can regulate innate immune response and induce macrophage polarization from M1 to M2 phenotype, could significantly alter leukocyte infiltration and reduce pulmonary fibrosis. Our findings with co-culture system indicated that hMSCs effectively reduced the secretion of of inflammation-related factors and induced a shift in macrophage polarization, consistent with in vivo results. Further investigations revealed that hMSCs treatment suppressed the activation of macrophage ROS/NLRP3 signaling pathway in vivo and in vitro. Moreover, administration of MCC950, a selective NLRP3 inhibitor has been shown to effectively reduce ROS production and subsequently alleviate inflammation induced by MHV-68. Taken together, our work has shown that hMSCs can effectively protect mice from lethal MHV-68 pneumonia, which may throw new light on strategy for combating human EBV-associated pneumonia.

Isolation, culture, and delivery considerations for the use of mesenchymal stem cells in potential therapies for acute liver failure

Acute liver failure (ALF) is a high-mortality syndrome for which liver transplantation is considered the only effective treatment option. A shortage of donor organs, high costs and surgical complications associated with immune rejection constrain the therapeutic effects of liver transplantation. Recently, mesenchymal stem cell (MSC) therapy was recognized as an alternative strategy for liver transplantation. Bone marrow mesenchymal stem cells (BMSCs) have been used in clinical trials of several liver diseases due to their ease of acquisition, strong proliferation ability, multipotent differentiation, homing to the lesion site, low immunogenicity and anti-inflammatory and antifibrotic effects. In this review, we comprehensively summarized the harvest and culture expansion strategies for BMSCs, the development of animal models of ALF of different aetiologies, the critical mechanisms of BMSC therapy for ALF and the challenge of clinical application.

A review of the application of mesenchymal stem cells in the field of hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is an effective treatment for many malignant hematological diseases. Mesenchymal stem cells (MSCs) are nonhematopoietic stem cells with strong self-renewal ability and multidirectional differentiation potential. They have the characteristics of hematopoietic support, immune regulation, tissue repair and regeneration, and homing. Recent studies have shown that HSCT combined with MSC infusion can promote the implantation of hematopoietic stem cells and enhance the reconstruction of hematopoietic function. Researchers have also found that MSCs have good preventive and therapeutic effects on acute and chronic graft-versus-host disease (GVHD), but there is still a lack of validation in large-sample randomized controlled trials. When using MSCs clinically, it is necessary to consider their dose, source, application time, application frequency and other relevant factors, but the specific impact of the above factors on the efficacy of MSCs still needs further clinical trial research. This review introduces the clinical roles of MSCs and summarizes the most recent progress concerning the use of MSCs in the field of HSCT, providing references for the later application of the combination of MSCs and HSCT in hematological diseases.

Current perspectives on mesenchymal stromal cell therapy for graft versus host disease

Graft versus host disease (GvHD) is the clinical condition in which bone marrow-derived mesenchymal stromal cells (MSCs) have been most frequently studied. In this review, we summarize the experience from clinical trials that have paved the way to translation. While MSC-based therapy has shown an exceptional safety profile, identifying potency assays and disease biomarkers that reliably predict the capacity of a specific MSC batch to alleviate GvHD has been difficult. As GvHD diagnosis and staging are based solely on clinical criteria, individual patients recruited in the same clinical trial may have vastly different underlying biology, obscuring trial outcomes and making it difficult to determine the benefit of MSCs in subgroups of patients. An accumulating body of evidence indicates the importance of considering not only the cell product but also patient-specific biomarkers and/or immune characteristics in determining MSC responsiveness. A mode of action where intravascular MSC destruction is followed by monocyte-efferocytosis-mediated skewing of the immune repertoire in a permissive inflammatory environment would both explain why cell engraftment is irrelevant for MSC efficacy and stress the importance of biologic differences between responding and nonresponding patients. We recommend a combined analysis of clinical outcomes and both biomarkers of disease activity and MSC potency assays to identify patients with GvHD who are likely to benefit from MSC therapy.

Safety and efficacy of mesenchymal stromal cell therapy for multi-drug-resistant acute and late-acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation

Graft versus host disease (GvHD) remains a significant risk for mortality and morbidity following allogeneic hematopoietic stem cell transplantation (HSCT). A growing literature supports successful applications of mesenchymal stromal cells (MSCs) for the treatment of steroid-refractory acute GvHD (aGvHD). However, there is limited knowledge about the effects of MSC treatment on late-acute GvHD (late aGvHD). In this article, we present our multicenter study on the safety and efficacy of MSC therapy for patients with steroid-refractory late aGvHD in comparison to those with aGvHD. The outcome measures include non-relapse mortality (NRM) and survival probability over a 2-year follow-up. The study includes a total of 76 patients with grades III-IV aGvHD (n = 46) or late aGvHD (n = 30), who had been treated with at least two lines of steroid-containing immunosuppressive therapy. Patients received weekly adipose or umbilical cord-derived MSC infusions at a dose of median 1.55 (ranging from 0.84 to 2.56) × 10⁶/kg in the aGvHD group, and 1.64 (ranging from 0.85 to 2.58) × 10⁶/kg in the late aGvHD group. This was an add-on treatment to ongoing conventional pharmaceutical management. In the aGvHD group, 23 patients received one or two infusions, 20 patients had 3-4, and three had ≥ 5. Likewise, in the late aGvHD group, 20 patients received one or two infusions, nine patients had 3-4, and one had ≥ 5. MSC was safe without acute or late adverse effects in 76 patients receiving over 190 infusions. In aGvHD group, 10.9% of the patients had a complete response (CR), 23.9% had a partial response (PR), and 65.2% had no response (NR). On the other hand, in the late aGvHD group, 23.3% of the patients had CR, 36.7% had PR, and the remaining 40% had NR. These findings were statistically significant (p = 0.031). Also, at the 2-year follow-up, the cumulative incidence of NRM was significantly lower in patients with late aGvHD than in patients with aGvHD at 40% (95% CI, 25-62%) versus 71% (95% CI, 59-86%), respectively (p = 0.032). In addition, the probability of survival at 2 years was significantly higher in patients with late aGvHD than in the aGvHD group at 59% (95% CI, 37-74%) versus 28% (95% CI, 13-40%), respectively (p = 0.002). To our knowledge, our study is the first to compare the safety and efficacy of MSC infusion(s) for the treatment of steroid-resistant late aGVHD and aGVHD. There were no infusion-related adverse effects in either group. The response rate to MSC therapy was significantly higher in the late aGvHD group than in the aGvHD group. In addition, at the 2-year follow-up, the survival and NRM rates were more favorable in patients with late aGVHD than in those with aGVHD. Thus, the results are encouraging and warrant further studies to optimize MSC-based treatment for late aGVHD.

Regulatory B Cells Contribute to the Clinical Response After Bone Marrow-Derived Mesenchymal Stromal Cell Infusion in Patients With Systemic Sclerosis

Mesenchymal stromal cells (MSCs) have recently emerged as an interesting therapeutic approach for patients with progressive systemic sclerosis (SSc), a rare and life-threatening orphan autoimmune disease. Whereas MSC immunomodulatory potential is considered as a central mechanism for their clinical benefit, very few data are available on the impact of MSCs on immune cell subsets in vivo. In the current extended study of a phase I/II clinical trial exploring the injection of a single dose of allogeneic bone marrow-MSCs (alloBM-MSCs) in patients with severe SSc (NCT02213705), we performed a longitudinal in-depth characterization of circulating immune cells in 19 MSC-treated patients, including 14 responders and 5 non-responders. By a combination of flow cytometry and transcriptomic analyses, we highlighted an increase in circulating CD24hiCD27posCD38lo/neg memory B cells, the main IL-10-producing regulatory B cell (Breg) subset, and an upregulation of IL10 expression in ex-vivo purified B cells, specifically in responder patients, early after the alloBM-MSC infusion. In addition, a deeper alteration of the B-cell compartment before alloBM-MSC treatment, including a higher expression of profibrotic cytokines IL6 and TGFβ by sorted B cells was associated with a non-responder clinical status. Finally, BM-MSCs were able to directly upregulate IL-10 production in activated B cells in vitro. These data suggest that cytokine-producing B cells, in particular Breg, are pivotal effectors of BM-MSC therapeutic activity in SSc. Their quantification as activity biomarkers in MSC potency assays and patient selection criteria may be considered to reach optimal clinical benefit when designing MSC-based clinical trials.

Modulation of Mesenchymal Stem Cells-Mediated Adaptive Immune Effectors' Repertoire in the Recovery of Systemic Lupus Erythematosus

The breakdown of self-tolerance of the immune response can lead to autoimmune conditions in which chronic inflammation induces tissue damage. Systemic lupus erythematosus (SLE) is a debilitating multisystemic autoimmune disorder with a high prevalence in women of childbearing age; however, SLE incidence, prevalence, and severity are strongly influenced by ethnicity. Although the mystery of autoimmune diseases remains unsolved, disturbance in the proportion and function of B cell subsets has a major role in SLE's pathogenesis. Additionally, colocalizing hyperactive T helper cell subgroups within inflammatory niches are indispensable. Despite significant advances in standard treatments, nonspecific immunosuppression, the risk of serious infections, and resistance to conventional therapies in some cases have raised the urgent need for new treatment strategies. Without the need to suppress the immune system, mesenchymal stem cells (MSCs), as ''smart" immune modulators, are able to control cellular and humoral auto-aggression responses by participating in precursor cell development. In lupus, due to autologous MSCs disorder, the ability of allogenic engrafted MSCs in tissue regeneration and resetting immune homeostasis with the provision of a new immunocyte repertoire has been considered simultaneously. In Brief The bone marrow mesenchymal stem cells (BM-MSCs) lineage plays a critical role in maintaining the hematopoietic stem-cell microstructure and modulating immunocytes. The impairment of BM-MSCs and their niche partially contribute to the pathogenesis of SLE-like diseases. Allogenic MSC transplantation can reconstruct BM microstructure, possibly contributing to the recovery of immunocyte phenotype restoration of immune homeostasis. In terms of future prospects of MSCs, artificially gained by ex vivo isolation and culture adaptation, the wide variety of potential mediators and mechanisms might be linked to the promotion of the immunomodulatory function of MSCs.

Improved efficacy of mesenchymal stromal cells stably expressing CXCR4 and IL-10 in a xenogeneic graft versus host disease mouse model

Previous clinical trials have shown that mesenchymal stromal cells (MSCs) can modulate graft versus host disease (GvHD) after allogeneic hematopoietic transplantation, although with variable efficacy. To improve the anti-GvHD effect of these cells, adipose tissue derived-human MSCs (Ad-MSCs) were transduced with a lentiviral vector conferring stable expression of CXCR4, a molecule involved in cell migration to inflamed sites, and IL-10, a cytokine with potent anti-inflammatory properties. In vitro experiments showed that the expression of these molecules in Ad-MSCs (named CXCR4-IL10-MSCs) efficiently enhanced their migration towards SDF-1α and also improved their immunomodulatory properties compared to unmodified Ad-MSCs (WT-MSCs). Moreover, using a humanized GvHD mouse model, CXCR4-IL10-MSCs showed improved therapeutic effects, which were confirmed by histopathologic analysis in the target organs. Additionally, compared to WT-MSCs, CXCR4-IL10-MSCs induced a more marked reduction in the number of pro-inflammatory Th1 and Th17 cells, a higher polarization towards an anti-inflammatory T cell profile (CD3⁺-IL10⁺ cells), and increased the number of regulatory T and B cells. Our in vitro and in vivo studies strongly suggest that CXCR4-IL10-MSCs should constitute an important new generation of MSCs for the treatment of GvHD in patients transplanted with allogeneic hematopoietic grafts.

Cell-based therapy in prophylaxis and treatment of chronic graft-versus-host disease

Hematopoietic allogeneic stem cell transplantation (allo-SCT) is a curative option for patients with hematological malignancies. However, due to disparities in major and minor histocompatibility antigens between donor and recipient, severe inflammatory complications can occur, among which chronic graft-versus-host disease (cGVHD) can be life-threatening. A classical therapeutic approach to the prevention and treatment of cGVHD has been broad immunosuppression, but more recently adjuvant immunotherapies have been tested. This review summarizes and discusses immunomodulatory approaches with T cells, including chimeric antigen receptor (CAR) and regulatory T cells, with natural killer (NK) cells and innate lymphoid cells (ILCs), and finally with mesenchymal stromal cells (MSC) and extracellular vesicles thereof. Clinical studies and pre-clinical research results are presented likewise.

Mesenchymal Stem Cells and MSCs-Derived Extracellular Vesicles in Infectious Diseases: From Basic Research to Clinical Practice

Mesenchymal stem cells (MSCs) are attractive in various fields of regenerative medicine due to their therapeutic potential and complex unique properties. Basic stem cell research and the global COVID-19 pandemic have given impetus to the development of cell therapy for infectious diseases. The aim of this review was to systematize scientific data on the applications of mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (MSC-EVs) in the combined treatment of infectious diseases. Application of MSCs and MSC-EVs in the treatment of infectious diseases has immunomodulatory, anti-inflammatory, and antibacterial effects, and also promotes the restoration of the epithelium and stimulates tissue regeneration. The use of MSC-EVs is a promising cell-free treatment strategy that allows solving the problems associated with the safety of cell therapy and increasing its effectiveness. In this review, experimental data and clinical trials based on MSCs and MSC-EVs for the treatment of infectious diseases are presented. MSCs and MSC-EVs can be a promising tool for the treatment of various infectious diseases, particularly in combination with antiviral drugs. Employment of MSC-derived EVs represents a more promising strategy for cell-free treatment, demonstrating a high therapeutic potential in preclinical studies.

Nestin+ Mesenchymal Precursors Generate Distinct Spleen Stromal Cell Subsets and Have Immunomodulatory Function

Mesenchymal stromal cells (MSCs) are known to be widespread in many tissues and possess a broad spectrum of immunoregulatory properties. They have been used in the treatment of a variety of inflammatory diseases; however, the therapeutic effects are still inconsistent owing to their heterogeneity. Spleen stromal cells have evolved to regulate the immune response at many levels as they are bathed in a complex inflammatory milieu during infection. Therefore, it is unknown whether they have stronger immunomodulatory effects than their counterparts derived from other tissues. Here, using a transgenic mouse model expressing GFP driven by the Nestin (Nes) promoter, Nes-GFP⁺ cells from bone marrow and spleen were collected. Artificial lymphoid reconstruction in vivo was performed. Cell phenotype, inhibition of T cell inflammatory cytokines, and in vivo therapeutic effects were assessed. We observed Nes-GFP⁺ cells colocalized with splenic stromal cells and further demonstrated that these Nes-GFP⁺ cells had the ability to establish ectopic lymphoid-like structures in vivo. Moreover, we showed that the Nes-GFP⁺ cells possessed the characteristics of MSCs. Spleen-derived Nes-GFP⁺ cells exhibited greater immunomodulatory ability in vitro and more remarkable therapeutic efficacy in inflammatory diseases, especially inflammatory bowel disease (IBD) than bone marrow-derived Nes-GFP⁺ cells. Overall, our data showed that Nes-GFP⁺ cells contributed to subsets of spleen stromal populations and possessed the biological characteristics of MSCs with a stronger immunoregulatory function and therapeutic potential than bone marrow-derived Nes-GFP⁺ cells.

“Adipose-derived mesenchymal stem cell therapy for the management of female sexual dysfunction: Literature reviews and study design of a clinical trial”

Hormone imbalance and female sexual dysfunction immensely affect perimenopausal female health and quality of life. Hormone therapy can improve female hormone deficiency, but long-term use increases the risk of cardiovascular diseases and cancer. Therefore, it is necessary to develop a novel effective treatment to achieve long-term improvement in female general and sexual health. This study reviewed factors affecting syndromes of female sexual dysfunction and its current therapy options. Next, the authors introduced research data on mesenchymal stromal cell/mesenchymal stem cell (MSC) therapy to treat female reproductive diseases, including Asherman’s syndrome, premature ovarian failure/primary ovarian insufficiency, and vaginal atrophy. Among adult tissue-derived MSCs, adipose tissue-derived stem cells (ASCs) have emerged as the most potent therapeutic cell therapy due to their abundant presence in the stromal vascular fraction of fat, high proliferation capacity, superior immunomodulation, and strong secretion profile of regenerative factors. Potential mechanisms and side effects of ASCs for the treatment of female sexual dysfunction will be discussed. Our phase I clinical trial has demonstrated the safety of autologous ASC therapy for women and men with sexual hormone deficiency. We designed the first randomized controlled crossover phase II trial to investigate the safety and efficacy of autologous ASCs to treat female sexual dysfunction in perimenopausal women. Here, we introduce the rationale, trial design, and methodology of this clinical study. Because aging and metabolic diseases negatively impact the bioactivity of adult-derived MSCs, this study will use ASCs cultured in physiological oxygen tension (5%) to cope with these challenges. A total of 130 perimenopausal women with sexual dysfunction will receive two intravenous infusions of autologous ASCs in a crossover design. The aims of the proposed study are to evaluate 1) the safety of cell infusion based on the frequency and severity of adverse events/serious adverse events during infusion and follow-up and 2) improvements in female sexual function assessed by the Female Sexual Function Index (FSFI), the Utian Quality of Life Scale (UQOL), and the levels of follicle-stimulating hormone (FSH) and estradiol. In addition, cellular aging biomarkers, including plasminogen activator inhibitor-1 (PAI-1), p16 and p21 expression in T cells and the inflammatory cytokine profile, will also be characterized. Overall, this study will provide essential insights into the effects and potential mechanisms of ASC therapy for perimenopausal women with sexual dysfunction. It also suggests direction and design strategies for future research.

Mesenchymal stromal cells: promising treatment for liver cirrhosis

Liver fibrosis is a wound-healing process that occurs in response to severe injuries and is hallmarked by the excessive accumulation of extracellular matrix or scar tissues within the liver. Liver fibrosis can be either acute or chronic and is induced by a variety of hepatotoxic causes, including lipid deposition, drugs, viruses, and autoimmune reactions. In advanced fibrosis, liver cirrhosis develops, a condition for which there is no successful therapy other than liver transplantation. Although liver transplantation is still a viable option, numerous limitations limit its application, including a lack of donor organs, immune rejection, and postoperative complications. As a result, there is an immediate need for a different kind of therapeutic approach. Recent research has shown that the administration of mesenchymal stromal cells (MSCs) is an attractive treatment modality for repairing liver injury and enhancing liver regeneration. This is accomplished through the cell migration into liver sites, immunoregulation, hepatogenic differentiation, as well as paracrine mechanisms. MSCs can also release a huge variety of molecules into the extracellular environment. These molecules, which include extracellular vesicles, lipids, free nucleic acids, and soluble proteins, exert crucial roles in repairing damaged tissue. In this review, we summarize the characteristics of MSCs, representative clinical study data, and the potential mechanisms of MSCs-based strategies for attenuating liver cirrhosis. Additionally, we examine the processes that are involved in the MSCs-dependent modulation of the immune milieu in liver cirrhosis. As a result, our findings lend credence to the concept of developing a cell therapy treatment for liver cirrhosis that is premised on MSCs. MSCs can be used as a candidate therapeutic agent to lengthen the survival duration of patients with liver cirrhosis or possibly reverse the condition in the near future.

Structural and Temporal Dynamics of Mesenchymal Stem Cells in Liver Diseases From 2001 to 2021: A Bibliometric Analysis

Background

Mesenchymal stem cells (MSCs) have important research value and broad application prospects in liver diseases. This study aims to comprehensively review the cooperation and influence of countries, institutions, authors, and journals in the field of MSCs in liver diseases from the perspective of bibliometrics, evaluate the clustering evolution of knowledge structure, and discover hot trends and emerging topics.

Methods

The articles and reviews related to MSCs in liver diseases were retrieved from the Web of Science Core Collection using Topic Search. A bibliometric study was performed using CiteSpace and VOSviewer.

Results

A total of 3404 articles and reviews were included over the period 2001-2021. The number of articles regarding MSCs in liver diseases showed an increasing trend. These publications mainly come from 3251 institutions in 113 countries led by China and the USA. Li L published the most papers among the publications, while Pittenger MF had the most co-citations. Analysis of the most productive journals shows that most are specialized in medical research, experimental medicine and cell biology, and cell & tissue engineering. The macroscopical sketch and micro-representation of the whole knowledge field are realized through co-citation analysis. Liver scaffold, MSC therapy, extracellular vesicle, and others are current and developing areas of the study. The keywords "machine perfusion", "liver transplantation", and "microRNAs" also may be the focus of new trends and future research.

Conclusions

In this study, bibliometrics and visual methods were used to review the research of MSCs in liver diseases comprehensively. This paper will help scholars better understand the dynamic evolution of the application of MSCs in liver diseases and point out the direction for future research.

Genetically engineered mesenchymal stromal cells as a new trend for treatment of severe acute graft-versus-host disease

Mesenchymal stem cells (MSCs) are a population of non-hematopoietic and self-renewing cells characterized by the potential to differentiate into different cell subtypes. MSCs have interesting features which have attracted a lot of attention in various clinical investigations. Some basic features of MSCs are including the weak immunogenicity (absence of MHC-II and costimulatory ligands accompanied by the low expression of MHC-I) and the potential of plasticity and multi-organ homing via expressing related surface molecules. MSCs by immunomodulatory effects could also ameliorate several immune-pathological conditions like graft-versus-host diseases (GVHD). The efficacy and potency of MSCs are the main objections of MSCs therapeutic applications. It suggested that improving the MSC immunosuppressive characteristic via genetic engineering to produce therapeutic molecules consider as one of the best options for this purpose. In this review, we explain the functions, immunologic properties, and clinical applications of MSCs to discuss the beneficial application of genetically modified MSCs in GVHD.

Intraperitoneally Delivered Mesenchymal Stem Cells Alleviate Experimental Colitis Through THBS1-Mediated Induction of IL-10-Competent Regulatory B Cells

Mesenchymal stem cells (MSCs) show promising therapeutic potential in treating inflammatory bowel disease (IBD), and intraperitoneal delivery of MSCs have become a more effective route for IBD treatment. However, the underlying mechanisms are still poorly understood. Here, we found that intraperitoneally delivered MSCs significantly alleviated experimental colitis. Depletion of peritoneal B cells, but not macrophages, clearly impaired the therapeutic effects of MSCs. Intraperitoneally delivered MSCs improved IBD likely by boosting the IL-10-producing B cells in the peritoneal cavity, and a single intraperitoneal injection of MSCs could significantly prevent disease severity in a recurrent mouse colitis model, with lower proinflammation cytokines and high level of IL-10. The gene expression profile revealed that thrombospondin-1 (THBS1) was dramatically upregulated in MSCs after coculture with peritoneal lavage fluid from colitis mice. Knockout of THBS1 expression in MSCs abolished their therapeutic effects in colitis and the induction of IL-10-producing B cells. Mechanistically, THBS1 modulates the activation of transforming growth factor-β (TGF-β), which combines with TGF-β receptors on B cells and contributes to IL-10 production. Blocking the interaction between THBS1 and latent TGF-β or inhibiting TGF-β receptors (TGF-βR) significantly reversed the THBS1-mediated induction of IL-10-producing B cells and the therapeutic effects on colitis. Collectively, our study revealed that intraperitoneally delivered MSCs secreted THBS1 to boost IL-10⁺Bregs and control the progression and recurrence of colitis, providing new insight for the prevention and treatment of IBD.

Mesenchymal stromal cells plus basiliximab, calcineurin inhibitor as treatment of steroid-resistant acute graft-versus-host disease: a multicenter, randomized, phase 3, open-label trial

BACKGROUND

Steroid-resistant (SR) acute graft-versus-host disease (aGVHD) lacks standard second-line treatment. Mesenchymal stromal cells (MSCs) have potential efficacy in SR aGVHD. We aimed to assess the efficacy and safety of MSCs combined with basiliximab and calcineurin inhibitor as second-line therapy for SR aGVHD.

METHODS

A randomized phase 3 trial involved 203 SR aGVHD patients at nine centers in China (September 2014-March 2019). Participants were randomized at a 1:1 ratio to receive second-line therapy with (n = 101) or without (n = 102) MSCs. The primary endpoint was the overall response (OR) at day 28. Secondary and safety endpoints included durable OR at day 56, failure-free survival, overall survival (OS), chronic GVHD (cGVHD), infection, hematological toxicity and relapse.

RESULTS

Of 203 patients, 198 (97.5%; mean age, 30.1 years; 40.4% women) completed the study. The OR at day 28 was higher in the MSC group than the control group (82.8% [82 patients] vs. 70.7% [70]; odds ratio, 2.00; 95% confidence interval [CI], 1.01-3.94; P = 0.043). The durable OR at day 56 was also higher in the MSC group (78.8% [78 patients] vs. 64.6% [64]; odds ratio, 2.02; 95% CI, 1.08-3.83; P = 0.027). The median failure-free survival was longer in the MSC group compared with control (11.3 months vs. 6.0 months; hazard ratio (HR) 0.68; 95% CI, 0.48-0.95, P = 0.024). The 2-year cumulative incidence of cGVHD was 39.5% (95% CI, 29.3-49.4%) and 62.7% (51.4-72.1%) in the MSC and control groups (HR 0.55, 95% CI, 0.36-0.84; P = 0.005). Within 180 days after study treatments, the most common grade 3 and 4 adverse events were infections (65 [65.7%] in the MSC group vs. 78 [78.8%] in the control group) and hematological toxicity (37 [37.4%] vs. 53 [53.5%]). The 3-year cumulative incidence of tumor relapse was 10.1% (95% CI, 5.2-17.1) and 13.5% (7.5-21.2%) in the MSC and control groups, respectively (HR 0.75, 95% CI, 0.34-1.67, P = 0.610).

CONCLUSIONS

MSCs plus second-line treatments increase the efficacy of SR aGVHD, decrease drug toxicity of second-line drugs and cGVHD without increasing relapse, and are well-tolerated. MSCs could be recommended as a second-line treatment option for aGVHD patients. Trial registration clinicaltrials.gov identifier: NCT02241018. Registration date: September 16, 2014, https://clinicaltrials.gov/ct2/show/NCT02241018 .

Mesenchymal Stem/Stromal Cells and Their Paracrine Activity-Immunomodulation Mechanisms and How to Influence the Therapeutic Potential

With high clinical interest to be applied in regenerative medicine, Mesenchymal Stem/Stromal Cells have been widely studied due to their multipotency, wide distribution, and relative ease of isolation and expansion in vitro. Their remarkable biological characteristics and high immunomodulatory influence have opened doors to the application of MSCs in many clinical settings. The therapeutic influence of these cells and the interaction with the immune system seems to occur both directly and through a paracrine route, with the production and secretion of soluble factors and extracellular vesicles. The complex mechanisms through which this influence takes place is not fully understood, but several functional manipulation techniques, such as cell engineering, priming, and preconditioning, have been developed. In this review, the knowledge about the immunoregulatory and immunomodulatory capacity of MSCs and their secretion products is revisited, with a special focus on the phenomena of migration and homing, direct cell action and paracrine activity. The techniques for homing improvement, cell modulation and conditioning prior to the application of paracrine factors were also explored. Finally, multiple assays where different approaches were applied with varying success were used as examples to justify their exploration.

Efficacy and safety of mesenchymal stem cells treatment for multidrug-resistant graft-versus-host disease after haploidentical allogeneic hematopoietic stem cell transplantation

PURPOSE

Graft-versus-host disease (GVHD) is an important complication after human leukocyte antigen (HLA) haploidentical donor (HID) hematopoietic stem cell transplantation (HSCT), which may lead to poor prognosis. Our study intends to identify the efficacy and safety of mesenchymal stem cells (MSCs) for multidrug-resistant (MDR)-GVHD after HID HSCT.

METHODS

MDR-GVHD was referring to GVHD remaining no response to at least two types of therapy, and hUCB-MSCs were given at the dose of (1.0-2.0) × 106/kg once a week.

RESULTS

A total of 21 patients were enrolled in this retrospective study (acute GVHD (aGVHD): n = 14, chronic GVHD (cGVHD): n = 7). The median dose of MSCs was 1.2 × 106 cells/kg (range, 0.8-1.8 × 106) cells/kg, and the median numbers of infusion were 2 (range, 1-7) and 3 (range, 2-12) for MDR-aGVHD and MDR-cGVHD patients, respectively. In MDR-aGVHD patients, the overall response rate (ORR) was 57.1%, including 50.0% complete response (CR) and 7.1% partial response (PR), and the median time to response was 49.5 days (range, 16-118) days. The 2-year probability of overall survival after MSCs was 64.3%. Five patients (35.7%) developed infections after MSCs, and no obvious hematologic toxicities were observed. Five MDR-aGVHD patients died after MSCs treatments because of GVHD progression (n = 1), severe infection (bacterial central nervous system infection: n = 1; fungal pneumonia: n = 2), and poor graft function (n = 1). In MDR-cGVHD patients, three patients (42.9%) achieved PR after MSCs and the median time to response was 56 days (22-84) days. The ORRs for moderate and severe cGVHD were 50.0% and 33.3%, respectively. Four MDR-cGVHD patients died after MSCs treatments because of GVHD progression (n = 2), severe fungal pneumonia (n = 1), and relapse (n = 1).

CONCLUSION

MSCs treatment may be safe and effective for MDR-GVHD after HID HSCT.

Mesenchymal stromal cells attenuate alveolar type 2 cells senescence through regulating NAMPT-mediated NAD metabolism

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive deadly fibrotic lung disease with high prevalence and mortality worldwide. The therapeutic potential of mesenchymal stem cells (MSCs) in pulmonary fibrosis may be attributed to the strong paracrine, anti-inflammatory, anti-apoptosis and immunoregulatory effects. However, the mechanisms underlying the therapeutic effects of MSCs in IPF, especially in terms of alveolar type 2 (AT2) cells senescence, are not well understood. The purpose of this study was to evaluate the role of MSCs in NAD metabolism and senescence of AT2 cells in vitro and in vivo.

Methods

MSCs were isolated from human bone marrow. The protective effects of MSCs injection in pulmonary fibrosis were assessed via bleomycin mouse models. The senescence of AT2 cells co-cultured with MSCs was evaluated by SA-β-galactosidase assay, immunofluorescence staining and Western blotting. NAD+ level and NAMPT expression in AT2 cells affected by MSCs were determined in vitro and in vivo. FK866 and NAMPT shRNA vectors were used to determine the role of NAMPT in MSCs inhibiting AT2 cells senescence.

Results

We proved that MSCs attenuate bleomycin-induced pulmonary fibrosis in mice. Senescence of AT2 cells was alleviated in MSCs-treated pulmonary fibrosis mice and when co-cultured with MSCs in vitro. Mechanistic studies showed that NAD+ and NAMPT levels were rescued in AT2 cells co-cultured with MSCs and MSCs could suppress AT2 cells senescence mainly via suppressing lysosome-mediated NAMPT degradation.

Conclusions

MSCs attenuate AT2 cells senescence by upregulating NAMPT expression and NAD+ levels, thus exerting protective effects in pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02688-w.

mRNA-engineered mesenchymal stromal cells expressing CXCR2 enhances cell migration and improves recovery in IBD

Mesenchymal stromal cells (MSCs) have shown significant heterogeneity in terms of therapeutic efficacy for inflammatory bowel disease (IBD) treatment, which may be due to an insufficient number of MSCs homing to the damaged tissue of the colon. Engineering MSCs with specific chemokine receptors can enhance the homing ability by lentiviral transduction. However, the unclear specific chemokine profile related to IBD and the safety concerns of viral-based gene delivery limit its application. Thus, a new strategy to modify MSCs to express specific chemokine receptors using mRNA engineering is developed to evaluate the homing ability of MSCs and its therapeutic effects for IBD. We found that CXCL2 and CXCL5 were highly expressed in the inflammatory colon, while MSCs minimally expressed the corresponding receptor CXCR2. Transient expression of CXCR2 in MSC was constructed and exhibited significantly enhanced migration to the inflamed colons, leading to a robust anti-inflammatory effect and high efficacy. Furthermore, the high expression of semaphorins7A on MSCs were found to induce the macrophages to produce IL-10, which may play a critical therapeutic role. This study demonstrated that the specific chemokine receptor CXCR2 mRNA-engineered MSCs not only improves the therapeutic efficacy of IBD but also provides an efficient and safe MSC modification strategy.

SDF-1α Facilitates Mesenchymal Stem Cells to Induce Regulatory B Cell Differentiation from Patients with Immune Thrombocytopenia

B cells play a central role in the pathogenesis of immune thrombocytopenia (ITP) by participating in humoral immunity. Meanwhile, regulatory B cells (Bregs), one subset of B cells, express negative regulatory effect on ITP. Mesenchymal stem cells (MSCs) have been demonstrated in the ability to induce immunosuppression, and stromal cell-derived factor-1α (SDF-1α) plays an important role in the migration and survival of MSCs. To investigate the mechanism of SDF-1α in controlling umbilical cord-derived MSCs (UC-MSCs) in inducing regulatory B cell differentiation of patients with ITP, we reconfirmed that SDF-1α promotes the proliferation of MSCs at the low doses of 0.05 μg/mL and 0.1 μg/mL but inhibits the proliferation and promotes the apoptosis of UC-MSCs at the high doses 0.5 μg/mL and 1 μg/mL; when UC-MSCs are cocultured with SDF-1α at 0.1 μg/mL, the decreased proportion of CD19⁺/CD24^hi/CD38^hi cells and IL-10-producing B cells (B 10 cell), considered as the Breg subset from ITP significantly enhanced, and the content of IL-10 in the supernatant is also obviously increased. The proportion of Bregs and the IL-10 secretion could be further promoted by the UC-MSCs treated with 0.1 μg/mL SDF-1α, which could also promote the miRNA-133 expression of UC-MSCs in an exosome-dependent manner; moreover, while the UC-MSCs were transfected with the miR-133 inhibitor, the proportion of induced Bregs decreased obviously when cocultured with peripheral blood mononuclear cells (PBMCs) of ITP. We conclude that UC-MSCs could effectively enhance the decreased proportion of Bregs from ITP; at appropriate concentrations, SDF-1α may promote the proliferating and survival ability of UC-MSCs and improve the production of Bregs induced by UC-MSCs through controlling miRNA-133 expression in the exosomes.

Mesenchymal stromal cells: Putative microenvironmental modulators become cell therapy

An exceptional safety profile has been shown in a large number of cell therapy clinical trials that use mesenchymal stromal cells (MSCs). However, reliable potency assays are still lacking to predict MSC immunosuppressive efficacy in the clinical setting. Nevertheless, MSCs are approved in Japan and Europe for the treatment of graft-versus-host and Crohn's fistular diseases, but not in the United States for any clinical indication. We discuss potential mechanisms of action for the therapeutic effects of MSC transplantation, experimental models that dissect tissue modulating function of MSCs, and approaches for identifying MSC effects in vivo by integrating biomarkers of disease and MSC activity.

Transplantation of mesenchymal stem cells ameliorates systemic lupus erythematosus and upregulates B10 cells through TGF-β1

BACKGROUND

Considerable experimental and clinical evidences have proved that human umbilical cord mesenchymal stem cells (UC-MSCs) transplantation was powerful in systemic lupus erythematosus (SLE) treatment. MSCs could upregulate regulatory B cells (Bregs) in the mice model of the other immune disease. However, the regulation of MSCs on Bregs in SLE environment remains unclear.

METHODS

To assess the abilities of UC-MSCs to treat SLE, MSCs were transferred intravenously to 17- to 18-week-old MRL/lpr mice. Four weeks later, mice were sacrificed. Survival rates, anti-dsDNA antibodies and renal histology were evaluated. CD4+ T helper (Th) cell subgroups and interleukin (IL)-10+ Bregs (B10) in the spleen were quantitated by flow cytometry. The changes of transforming growth factor (TGF)-β1, IL-6 and indoleamine 2,3-dioxyenase (IDO) mRNAs expressed by MSCs after co-cultured with B cells were detected using real-time polymerase chain reaction (RT-PCR). MSCs were infected by lentivirus carrying TGF-β1 shRNAs, then MSCs with low expression of TGF-β1 were conducted for co-culture in vitro and transplantation experiments in vivo.

RESULTS

UC-MSCs transplantation could efficiently downregulate 24 h proteinuria and anti-dsDNA antibodies, correct Treg/Th17/Th1 imbalances and increase the frequency of B10 cells. The expression of TGF-β1 in MSCs was significantly increased after co-culture with B cells. Downregulation of TGF-β1 in MSCs could significantly attenuate the upregulation of B10 by MSCs in vitro and in vivo. Downregulation of TGF-β1 also compromised the immunomodulation effects of MSCs on Th17 and Treg cells and the therapeutic effects of MSC transplantation.

CONCLUSIONS

UC-MSCs could protect against SLE in mice and upregulate IL-10+ Bregs via TGF-β1.

The Kynurenine Pathway-New Linkage between Innate and Adaptive Immunity in Autoimmune Endocrinopathies

The kynurenine pathway (KP) is highly regulated in the immune system, where it promotes immunosuppression in response to infection or inflammation. Indoleamine 2,3-dioxygenase 1 (IDO1), the main enzyme of KP, has a broad spectrum of activity on immune cells regulation, controlling the balance between stimulation and suppression of the immune system at sites of local inflammation, relevant to a wide range of autoimmune and inflammatory diseases. Various autoimmune diseases, among them endocrinopathies, have been identified to date, but despite significant progress in their diagnosis and treatment, they are still associated with significant complications, morbidity, and mortality. The precise cellular and molecular mechanisms leading to the onset and development of autoimmune disease remain poorly clarified so far. In breaking of tolerance, the cells of the innate immunity provide a decisive microenvironment that regulates immune cells' differentiation, leading to activation of adaptive immunity. The current review provided a comprehensive presentation of the known role of IDO1 and KP activation in the regulation of the innate and adaptive arms of the immune system. Significant attention has been paid to the immunoregulatory role of IDO1 in the most prevalent, organ-specific autoimmune endocrinopathies-type 1 diabetes mellitus (T1DM) and autoimmune thyroiditis.

Human Wharton's jelly-derived mesenchymal stem cells alleviate concanavalin A-induced fulminant hepatitis by repressing NF-κB signaling and glycolysis

Background

Fulminant hepatitis is a severe life-threatening clinical condition with rapid progressive loss of liver function. It is characterized by massive activation and infiltration of immune cells into the liver and disturbance of inflammatory cytokine production. Mesenchymal stem cells (MSCs) showed potent immunomodulatory properties. Transplantation of MSCs is suggested as a promising therapeutic approach for a host of inflammatory conditions.

Methods

In the current study, a well-established concanavalin A (Con A)-induced fulminant hepatitis mouse model was used to investigate the effects of transplanting human umbilical cord Wharton's jelly-derived MSCs (hWJ-MSCs) on fulminant hepatitis.

Results

We showed that hWJ-MSCs effectively alleviate fulminant hepatitis in mouse models, primarily through inhibiting T cell immunity. RNA sequencing of liver tissues and human T cells co-cultured with hWJ-MSCs showed that NF-κB signaling and glycolysis are two main pathways mediating the protective role of hWJ-MSCs on both Con A-induced hepatitis in vivo and T cell activation in vitro.

Conclusion

In summary, our data confirmed the potent therapeutic role of MSCs-derived from Wharton's jelly of human umbilical cord on Con A-induced fulminant hepatitis, and uncovered new mechanisms that glycolysis metabolic shift mediates suppression of T cell immunity by hWJ-MSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02560-x.

Treatment of Steroid-Refractory Acute Graft-Versus-Host Disease Using Commercial Mesenchymal Stem Cell Products

Acute graft-versus-host disease (GVHD) is a life-threatening complication that can develop after allogeneic hematopoietic stem cell transplantation. In particular, the prognosis of patients with steroid-refractory acute GVHD is extremely poor. Ryoncil™ (remestemcel-L), a human bone marrow-derived mesenchymal stem cell (MSC) product, failed to show superiority over placebo in patients with steroid-refractory acute GVHD, but it was approved for use in pediatric patients in Canada and New Zealand based on the results of a subgroup analysis. Temcell^®, an equivalent manufactured MSC product to remestemcel-L, was approved in Japan based on small single-arm studies by using a regulation for regenerative medicine in 2016. The efficacy of Temcell was evaluated in 381 consecutive patients treated with Temcell during the initial 3 years after its approval. Interestingly, its real-world efficacy was found to be equivalent to that observed in a prospective study of remestemcel-L with strict eligibility criteria. In this article, the potential of MSC therapy in the treatment of acute GVHD is discussed. A meticulous comparison of studies of remestemcel-L and Temcell, remestemcel-L/Temcell and ruxolitinib, and remestemcel-L/Temcell and thymoglobulin showed that the precise position of remestemcel-L/Temcell therapy in the treatment of acute GVHD remains to be determined.

CD5-Positive B Lymphocytes after Kidney Transplantation

Kidney transplantation is the treatment of choice for end-stage kidney diseases. Unfortunately, kidney allograft recipients rarely develop tolerance or accommodation and require life-long immunosuppression. Among many other regulatory mechanisms, CD5+ B lymphocytes (mainly B-1a) seem to be involved in the process of allograft acceptance. These cells are the major source of natural, low-affinity antibodies, which are polyreactive. Thus, we hypothesized that CD5+ B cells could be referred to as a biomarker in those patients who developed accommodation towards kidney allotransplant. In this study, 52 low-immunized kidney transplant recipients were evaluated for transplant outcome up to 8 y post-transplant. The follow up included anti-HLA antibodies, B cells phenotype and cytokines. We have identified a cohort of recipients who produced alloantibodies (Abs+), which was associated with increased levels of CD5+ B cells, mainly during the first year after transplantation but also later on. Importantly, creatinine levels were comparable between Abs+ and Abs− allorecipients at 2 years after the transplantation and graft survival rate was comparable between these groups even eight years post-transplant. So, it seems that despite the presence of alloantibodies the graft function was sustained when the level of CD5+ B cells was increased. Targeting CD5+ B cells may be a valuable therapeutic option to increase transplant success. The phenotype can be also tried as a biomarker to increase the effectiveness of individualized post-transplant treatments.

Mesenchymal Stem Cells and Tuberculosis: Clinical Challenges and Opportunities

Tuberculosis (TB) is one of the communicable diseases caused by Mycobacterium tuberculosis (Mtb) infection, affecting nearly one-third of the world's population. However, because the pathogenesis of TB is still not fully understood and the development of anti-TB drug is slow, TB remains a global public health problem. In recent years, with the gradual discovery and confirmation of the immunomodulatory properties of mesenchymal stem cells (MSCs), more and more studies, including our team's research, have shown that MSCs seem to be closely related to the growth status of Mtb and the occurrence and development of TB, which is expected to bring new hope for the clinical treatment of TB. This article reviews the relationship between MSCs and the occurrence and development of TB and the potential application of MSCs in the treatment of TB.

Efficacy and Safety of Bone Marrow-Derived Mesenchymal Stem Cells for Chronic Antibody-Mediated Rejection After Kidney Transplantation- A Single-Arm, Two-Dosing-Regimen, Phase I/II Study

Objective

To investigate the efficacy and safety of bone marrow-derived mesenchymal stem cells (BM-MSCs) on chronic active antibody-mediated rejection (cABMR) in the kidney allograft.

Methods

Kidney recipients with biopsy-proven cABMR were treated with allogeneic third-party BM-MSCs in this open-label, single-arm, single-center, two-dosing-regimen phase I/II clinical trial. In Regimen 1 (n=8), BM-MSCs were administered intravenously at a dose of 1.0×10⁶ cells/kg monthly for four consecutive months, while in Regimen 2 (n=15), the BM-MSCs dose was 1.0×10⁶ cells/kg weekly during four consecutive weeks. The primary endpoints were the absolute change of estimated glomerular filtration rate (eGFR) from baseline (delta eGFR) and the incidence of adverse events associated with BM-MSCs administration 24 months after the treatment. Contemporaneous cABMR patients who did not receive BM-MSCs were retrospectively analyzed as the control group (n =30).

Results

Twenty-three recipients with cABMR received BM-MSCs. The median delta eGFR of the total BM-MSCs treated patients was -4.3 ml/min per 1.73m² (interquartile range, IQR -11.2 to 1.2) 2 years after BM-MSCs treatment (P=0.0233). The median delta maximum donor-specific antibody (maxDSA) was -4310 (IQR -9187 to 1129) at 2 years (P=0.0040). The median delta eGFR of the control group was -12.7 ml/min per 1.73 m² (IQR -22.2 to -3.5) 2 years after the diagnosis, which was greater than that of the BM-MSCs treated group (P=0.0342). The incidence of hepatic enzyme elevation, BK polyomaviruses (BKV) infection, cytomegalovirus (CMV) infection was 17.4%, 17.4%, 8.7%, respectively. There was no fever, anaphylaxis, phlebitis or venous thrombosis, cardiovascular complications, or malignancy after BM-MSCs administration. Flow cytometry analysis showed a significant decreasing trend of CD27^-IgD^- double negative B cells subsets and trend towards the increase of CD3⁺CD4⁺PD-1⁺/lymphocyte population after MSCs therapy. Multiplex analysis found TNF-α, CXCL10, CCL4, CCL11 and RANTES decreased after MSCs treatment.

Conclusion

Kidney allograft recipients with cABMR are tolerable to BM-MSCs. Immunosuppressive drugs combined with intravenous BM-MSCs can delay the deterioration of allograft function, probably by decreasing DSA level and reducing DSA-induced injury. The underlying mechanism may involve immunomodulatory effect of MSCs on peripheral B and T cells subsets.

Mangiferin Promotes Bregs Level, Activates Nrf2 Antioxidant Signaling, and Inhibits Proinflammatory Cytokine Expression in Murine Splenic Mononuclear Cells In Vitro

Recent studies indicated that regulatory B cells (Bregs) and nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant signaling pathway play important roles in the pathogenesis of chronic graft-versus-host disease (cGVHD). Mangiferin (MA), a polyphenol compound, has been reported to activate Nrf2/antioxidant-responsive element (ARE) signaling pathway. This study was aimed to investigate the effects of MA on Bregs and Nrf2 antioxidant signaling in murine splenic mononuclear cells (MNCs) in vitro. Our results revealed that MA could increase the Bregs level in murine splenic MNCs. Moreover, MA up-regulated the expression of Bregs-associated immunosuppressive factor interleukin-10 (IL-10) by activating the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK) signaling in murine splenic MNCs. Meanwhile, MA inhibited the proinflammatory cytokines IL-2 and interferon-γ (INF-γ) at both mRNA and protein levels. MA also enhanced the transcription and protein expression of Nrf2 and NADPH quinine oxidoreductase 1 (NQO1), whereas decreased that of Kelch-like ECH-associated protein 1 (Keap1) in murine splenic MNCs. Moreover, MA promoted the proliferation and inhibited the apoptosis of murine splenic MNCs. These results suggested that MA exerts immunosuppressive effects by upregulating the Bregs level, activating the Nrf2 antioxidant pathway, and inhibiting the expression of pro-immunoinflammatory factors. MA, as a natural immunomodulatory and anti-inflammatory agent, may have a potential role in the prophylaxis and treatment of cGVHD.

The Impact of New Immunological Therapeutic Strategies on Recurrent Miscarriage and Recurrent Implantation Failure

Maternal-fetal immune dysregulation is one of the risk factors that increases the probability of embryo rejection and reproductive failure. The stimulation of immunological tolerance and suppression of immunological rejection are prerequisites for protecting embryos and preventing immunological attacks. Hence, it appears that immunomodulatory and immunosuppressive therapies can manage reproductive failures by controlling immune cells. The current medical literature has shown that immunotherapy approaches and cell therapy have promising results in improving pregnancy outcomes and live birth rates. These outcomes are obtained by regulating maternal immune responses, and exerting positive effects on human reproductive processes.