Immune-related antigens, surface molecules and regulatory factors in human-derived mesenchymal stromal cells: the expression and impact of inflammatory priming

The Immunological Profile of Adipose Mesenchymal Stromal/Stem Cells after Cell Expansion and Inflammatory Priming

BACKGROUND

AT-MSCs display great immunoregulatory features, making them potential candidates for cell-based therapy. This study aimed to evaluate the "RBC lysis buffer" isolation protocol and immunological profiling of the so-obtained AT-MSCs.

METHODS

We established an immune-comparative screening of AT-MSCs throughout in vitro cell expansion (PM, P1, P2, P3, P4) and inflammatory priming regarding the expression of 28 cell-surface markers, 6 cytokines/chemokines, and 10 TLR patterns.

FINDINGS

AT-MSCs were highly expandable and sensitive to microenvironment challenges, hereby showing plasticity in distinct expression profiles. Both cell expansion and inflammation differentially modulated the expression profile of CD34, HLA-DR, CD40, CD62L, CD200 and CD155, CD252, CD54, CD58, CD106, CD274 and CD112. Inflammation resulted in a significant increase in the expression of the cytokines IL-6, IL-8, IL-1β, IL-1Ra, CCL5, and TNFα. Depending on the culture conditions, the expression of the TLR pattern was distinctively altered with TLR1-4, TLR7, and TLR10 being increased, whereas TLR6 was downregulated. Protein network and functional enrichment analysis showed that several trophic and immune responses are likely linked to these immunological changes.

CONCLUSIONS

AT-MSCs may sense and actively respond to tissue challenges by modulating distinct and specific pathways to create an appropriate immuno-reparative environment. These mechanisms need to be further characterized to identify and assess a molecular target that can enhance or impede the therapeutic ability of AT-MSCs, which therefore will help improve the quality, safety, and efficacy of the therapeutic strategy.

Comprehensive analysis of human monocyte subsets using full-spectrum flow cytometry and hierarchical marker clustering

Introduction

Exploring monocytes' roles within the tumor microenvironment is crucial for crafting targeted cancer treatments.

Methods

This study unveils a novel methodology utilizing four 20-color flow cytometry panels for comprehensive peripheral immune system phenotyping, specifically targeting classical, intermediate, and non-classical monocyte subsets.

Results

By applying advanced dimensionality reduction techniques like t-distributed stochastic neighbor embedding (tSNE) and FlowSom analysis, we performed an extensive profiling of monocytes, assessing 50 unique cell surface markers related to a wide range of immunological functions, including activation, differentiation, and immune checkpoint regulation.

Discussion

This in-depth approach significantly refines the identification of monocyte subsets, directly supporting the development of personalized immunotherapies and enhancing diagnostic precision. Our pioneering panel for monocyte phenotyping marks a substantial leap in understanding monocyte biology, with profound implications for the accuracy of disease diagnostics and the success of checkpoint-inhibitor therapies. Key findings include revealing distinct marker expression patterns linked to tumor progression and providing new avenues for targeted therapeutic interventions.

The immunogenic profile and immunomodulatory function of mesenchymal stromal / stem cells in the presence of Ptychotis verticillata

Mesenchymal stromal/stem cells (MSCs) are considered to be a promising immunotherapeutic tool due to their easy accessibility, culture expansion possibilities, safety profile, and immunomodulatory properties. Although several studies have demonstrated the therapeutic effects of MSCs, their efficacy needs to be improved while also preserving their safety. It has been suggested that cell homeostasis may be particularly sensitive to plant extracts. The impact of natural compounds on immunity is thus a fascinating and growing field. Ptychotis verticillata and its bioactive molecules, carvacrol and thymol, are potential candidates for improving MSC therapeutic effects. They can be used as immunotherapeutic agents to regulate MSC functions and behavior during immunomodulation. Depending on their concentrations and incubation time, these compounds strengthened the immunomodulatory functions of MSCs while maintaining their immune-evasive profile. Incubating MSCs with carvacrol and thymol does not alter their hypoimmunogenicity, as no induction of the allogeneic immune response was observed. MSCs also showed enhanced abilities to reduce the proliferation of activated T cells. Thus, MSCs are immunologically responsive to bioactive molecules derived from PV. The bioactivity may depend on the whole phyto-complex of the oil. These findings may contribute to the development of safe and efficient immunotherapeutic MSCs by using medicinal plant-derived active molecules.

Oncolytic Virotherapy: A New Paradigm in Cancer Immunotherapy

Oncolytic viruses (OVs) are emerging as potential treatment options for cancer. Natural and genetically engineered viruses exhibit various antitumor mechanisms. OVs act by direct cytolysis, the potentiation of the immune system through antigen release, and the activation of inflammatory responses or indirectly by interference with different types of elements in the tumor microenvironment, modification of energy metabolism in tumor cells, and antiangiogenic action. The action of OVs is pleiotropic, and they show varied interactions with the host and tumor cells. An important impediment in oncolytic virotherapy is the journey of the virus into the tumor cells and the possibility of its binding to different biological and nonbiological vectors. OVs have been demonstrated to eliminate cancer cells that are resistant to standard treatments in many clinical trials for various cancers (melanoma, lung, and hepatic); however, there are several elements of resistance to the action of viruses per se. Therefore, it is necessary to evaluate the combination of OVs with other standard treatment modalities, such as chemotherapy, immunotherapy, targeted therapies, and cellular therapies, to increase the response rate. This review provides a comprehensive update on OVs, their use in oncolytic virotherapy, and the future prospects of this therapy alongside the standard therapies currently used in cancer treatment.

Factors Defining Human Adipose Stem/Stromal Cell Immunomodulation in Vitro

Human adipose tissue-derived stem/stromal cells (hASCs) are adult multipotent mesenchymal stem/stromal cells with immunomodulatory capacities. Here, we present up-to-date knowledge on the impact of different experimental and donor-related factors on hASC immunoregulatory functions in vitro. The experimental determinants include the immunological status of hASCs relative to target immune cells, contact vs. contactless interaction, and oxygen tension. Factors such as the ratio of hASCs to immune cells, the cellular context, the immune cell activation status, and coculture duration are also discussed. Conditioning of hASCs with different approaches before interaction with immune cells, hASC culture in xenogenic or xenofree culture medium, hASC culture in two-dimension vs. three-dimension with biomaterials, and the hASC passage number are among the experimental parameters that greatly may impact the hASC immunosuppressive potential in vitro, thus, they are also considered. Moreover, the influence of donor-related characteristics such as age, sex, and health status on hASC immunomodulation in vitro is reviewed. By analysis of the literature studies, most of the indicated determinants have been investigated in broad non-standardized ranges, so the results are not univocal. Clear conclusions cannot be drawn for the fine-tuned scenarios of many important factors to set a standard hASC immunopotency assay. Such variability needs to be carefully considered in further standardized research. Importantly, field experts' opinions may help to make it clearer.

The expression mechanism of programmed cell death 1 ligand 1 and its role in immunomodulatory ability of mesenchymal stem cells

Programmed cell death 1 ligand 1 (PD-L1) is an important immunosuppressive molecule, which inhibits the function of T cells and other immune cells by binding to the receptor programmed cell death-1. The PD-L1 expression disorder plays an important role in the occurrence, development, and treatment of sepsis or other inflammatory diseases, and has become an important target for the treatment of these diseases. Mesenchymal stem cells (MSCs) are a kind of pluripotent stem cells with multiple differentiation potential. In recent years, MSCs have been found to have a strong immunosuppressive ability and are used to treat various inflammatory insults caused by hyperimmune diseases. Moreover, PD-L1 is deeply involved in the immunosuppressive events of MSCs and plays an important role in the treatment of various diseases. In this review, we will summarize the main regulatory mechanism of PD-L1 expression, and discuss various biological functions of PD-L1 in the immune regulation of MSCs.

Tumor Necrosis Factor-Alpha Induces Proangiogenic Profiling of Cardiosphere-Derived Cell Secretome and Increases Its Ability to Stimulate Angiogenic Properties of Endothelial Cells

Ischemic heart disease and its complications, such as myocardial infarction and heart failure, are the leading causes of death in modern society. The adult heart innately lacks the capacity to regenerate the damaged myocardium after ischemic injury. Multiple lines of evidence indicated that stem-cell-based transplantation is one of the most promising treatments for damaged myocardial tissue. Different kinds of stem cells have their advantages for treating ischemic heart disease. One facet of their mechanism is the paracrine effect of the transplanted cells. Particularly promising are stem cells derived from cardiac tissue per se, referred to as cardiosphere-derived cells (CDCs), whose therapeutic effect is mediated by the paracrine mechanism through secretion of multiple bioactive molecules providing immunomodulatory, angiogenic, anti-fibrotic, and anti-inflammatory effects. Although secretome-based therapies are increasingly being used to treat various cardiac pathologies, many obstacles remain because of population heterogeneity, insufficient understanding of potential modulating compounds, and the principles of secretome regulation, which greatly limit the feasibility of this technology. In addition, components of the inflammatory microenvironment in ischemic myocardium may influence the secretome content of transplanted CDCs, thus altering the efficacy of cell therapy. In this work, we studied how Tumor necrosis factor alpha (TNFa), as a key component of the pro-inflammatory microenvironment in damaged myocardium from ischemic injury and heart failure, may affect the secretome content of CDCs and their angiogenic properties. We have shown for the first time that TNFa may act as a promising compound modulating the CDC secretome, which induces its profiling to enhance proangiogenic effects on endothelial cells. These results allow us to elucidate the underlying mechanisms of the impact of the inflammatory microenvironment on transplanted CDCs and may contribute to the optimization of CDC efficiency and the development of the technology for producing the CDC secretome with enhanced proangiogenic properties for cell-free therapy.

Regulation of Immune Checkpoint Antigen CD276 (B7-H3) on Human Placenta-Derived Mesenchymal Stromal Cells in GMP-Compliant Cell Culture Media

Therapies utilizing autologous mesenchymal cell delivery are being investigated as anti-inflammatory and regenerative treatments for a broad spectrum of age-related diseases, as well as various chronic and acute pathological conditions. Easily available allogeneic full-term human placenta mesenchymal stromal cells (pMSCs) were used as a potential pro-regenerative, cell-based therapy in degenerative diseases, which could be applied also to elderly individuals. To explore the potential of allogeneic pMSCs transplantation for pro-regenerative applications, such cells were isolated from five different term-placentas, obtained from the dissected maternal, endometrial (mpMSCs), and fetal chorion tissues (fpMSCs), respectively. The proliferation rate of the cells in the culture, as well as their shape, in vitro differentiation potential, and the expression of mesenchymal lineage and stem cell markers, were investigated. Moreover, we studied the expression of immune checkpoint antigen CD276 as a possible modulation of the rejection of transplanted non-HLA-matched homologous or even xeno-transplanted pMSCs. The expression of the cell surface markers was also explored in parallel in the cryosections of the relevant intact placenta tissue samples. The expansion of pMSCs in a clinical-grade medium complemented with 5% human platelet lysate and 5% human serum induced a significant expression of CD276 when compared to mpMSCs expanded in a commercial medium. We suggest that the expansion of mpMSCs, especially in a medium containing platelet lysate, elevated the expression of the immune-regulatory cell surface marker CD276. This may contribute to the immune tolerance towards allogeneic pMSC transplantations in clinical situations and even in xenogenic animal models of human diseases. The endurance of the injected comparably young human-term pMSCs may promote prolonged effects in clinical applications employing non-HLA-matched allogeneic cell therapy for various degenerative disorders, especially in aged adults.

HLA-Ehigh /HLA-Ghigh /HLA-IIlow Human iPSC-Derived Cardiomyocytes Exhibit Low Immunogenicity for Heart Regeneration

Although human pluripotent stem cells (hPSCs)-derived cardiomyocytes (hPSC-CMs) can remuscularize infarcted hearts and restore post-infarct cardiac function, post-transplant rejection resulting from human leukocyte antigen (HLA) mismatching is an enormous obstacle. It is crucial to identify hypoimmunogenic hPSCs for allogeneic cell therapy. This study is conducted to demonstrate the immune privilege of HLA-Ehigh /HLA-Ghigh /HLA-IIlow human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSC-CMs). Ischemia-reperfusion surgery is done to create transmural myocardial infarction in rats. At post-infarct 4 days, hPSC-CMs (1.0×107 cells per kg), including human embryonic stem cell-derived cardiomyocytes (hESC-CMs), HLA-Elow/HLA-Glow/HLA-IIhigh hiPSC-CMs, and HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs, are injected into the infarcted myocardium. Under the treatment of very low dose cyclosporine A (CsA), only HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs survive in vivo and improved post-infarct cardiac function with infarct size reduction. HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs activate the SHP-1 signaling pathway of natural killer (NK) cells and cytotoxic T cells to evade attack by NK cells and cytotoxic T cells. Herein, it is demonstrated that using a clinically relevant CsA dose, HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs repair the infarcted myocardium and restore the post-infarct heart function. HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSCs are less immunogenic and may serve as platforms for regeneration medicine.

Interaction between Mesenchymal Stem Cells and Immune Cells during Bone Injury Repair

Fractures are the most common large organ trauma in humans. The initial inflammatory response promotes bone healing during the initial post-fracture phase, but chronic and persistent inflammation due to infection or other factors does not contribute to the healing process. The precise mechanisms by which immune cells and their cytokines are regulated in bone healing remain unclear. The use of mesenchymal stem cells (MSCs) for cellular therapy of bone injuries is a novel clinical treatment approach. Bone progenitor MSCs not only differentiate into bone, but also interact with the immune system to promote the healing process. We review in vitro and in vivo studies on the role of the immune system and bone marrow MSCs in bone healing and their interactions. A deeper understanding of this paradigm may provide clues to potential therapeutic targets in the healing process, thereby improving the reliability and safety of clinical applications of MSCs to promote bone healing.

Transcriptomic Heterogeneity of Human Mesenchymal Stem Cells Derived from Bone Marrow, Dental Pulp, Adipose Tissue, and Umbilical Cord

Compared with mesenchymal stem cells (MSCs) obtained from other tissue sources, those derived from umbilical cord (UC) tissue exhibit numerous advantages and vast potential for therapeutic applications. However, MSCs from different tissue sources are heterogeneous, and therefore, the therapeutic efficacy of UC-derived MSCs as a replacement for other tissue-derived MSCs needs to be studied. To better understand the distinctions between UC-derived MSCs and MSCs derived from other tissues, we conducted a transcriptome analysis of MSCs obtained from UC and three other tissues. Correlation analysis revealed the strongest correlation between UC-MSCs (UC-MSCs) and bone marrow-MSCs (BM-MSCs). Compared with UC-MSCs, the lower differentially expressed genes of BM-MSCs, dental pulp-MSCs (DP-MSCs), and adipose tissue-MSCs (AP-MSCs) were predominantly enriched in actin-related terms, while higher differentially expressed genes were predominantly enriched in immunological processes. We also analyzed the distribution of 34 frequently or highly expressed cell characterization molecules in BM-MSCs, DP-MSCs, AP-MSCs, and UC-MSCs. CD200 (FPKM >10) was only detected in UC-MSCs, while CD106 was detected in AD-MSCs and DP-MSCs (FPKM >10). The reliability of transcriptomic data analysis was verified by quantitative real-time PCR. Finally, we recommend the use of CD200, CD106, and other similar markers with unstable expression as benchmark molecules to monitor the proliferation and differentiation potential of MSCs. This study provides comprehensive insights into the heterogeneity between UC-MSCs and MSCs derived from other tissues, which can guide the therapeutic application of UC-MSCs.

Metabolites and Immune Response in Tumor Microenvironments

The remodeled cancer cell metabolism affects the tumor microenvironment and promotes an immunosuppressive state by changing the levels of macro- and micronutrients and by releasing hormones and cytokines that recruit immunosuppressive immune cells. Novel dietary interventions such as amino acid restriction and periodic fasting mimicking diets can prevent or dampen the formation of an immunosuppressive microenvironment by acting systemically on the release of hormones and growth factors, inhibiting the release of proinflammatory cytokines, and remodeling the tumor vasculature and extracellular matrix. Here, we discuss the latest research on the effects of these therapeutic interventions on immunometabolism and tumor immune response and future scenarios pertaining to how dietary interventions could contribute to cancer therapy.

Skin-Derived ABCB5+ Mesenchymal Stem Cells for High-Medical-Need Inflammatory Diseases: From Discovery to Entering Clinical Routine

The ATP-binding cassette superfamily member ABCB5 identifies a subset of skin-resident mesenchymal stem cells (MSCs) that exhibit potent immunomodulatory and wound healing-promoting capacities along with superior homing ability. The ABCB5+ MSCs can be easily accessed from discarded skin samples, expanded, and delivered as a highly homogenous medicinal product with standardized potency. A range of preclinical studies has suggested therapeutic efficacy of ABCB5+ MSCs in a variety of currently uncurable skin and non-skin inflammatory diseases, which has been substantiated thus far by distinct clinical trials in chronic skin wounds or recessive dystrophic epidermolysis bullosa. Therefore, skin-derived ABCB5+ MSCs have the potential to provide a breakthrough at the forefront of MSC-based therapies striving to fulfill current unmet medical needs. The most recent milestones in this regard are the approval of a phase III pivotal trial of ABCB5+ MSCs for treatment of recessive dystrophic and junctional epidermolysis bullosa by the US Food and Drug Administration, and national market access of ABCB5+ MSCs (AMESANAR®) for therapy-refractory chronic venous ulcers under the national hospital exemption pathway in Germany.

Reprogramming the tumor microenvironment to improve the efficacy of cancer immunotherapies

The immunotherapeutic approaches based on checkpoint inhibitors, tumor vaccination, immune cell-based therapy, and cytokines were developed to engage the patient's immune system against cancer and better survival of them. While potent, however, preclinical and clinical data have identified that abnormalities in the tumor microenvironment (TME) can affect the efficacy of immunotherapies in some cancers. It is therefore imperative to develop new therapeutic interventions that will enable to overcome tumor-supportive TME and restrain anti-tumor immunity in patients that acquire resistance to current immunotherapies. Therefore, recognition of the essential nature of the tolerogenic TME may lead to a shift from the immune-suppressive TME to an immune-stimulating phenotype. Here, we review the composition of the TME and its effect on tumor immunoediting and then present how targeted monotherapy or combination therapies can be employed for reprogramming educated TME to improve current immunotherapies outcomes or elucidate potential therapeutic targets.

Cell-based drug delivery systems and their in vivo fate

Cell-based drug delivery systems (DDSs) have received attention recently because of their unique biological properties and self-powered functions, such as excellent biocompatibility, low immunogenicity, long circulation time, tissue-homingcharacteristics, and ability to cross biological barriers. A variety of cells, including erythrocytes, stem cells, and lymphocytes, have been explored as functional vectors for the loading and delivery of various therapeutic payloads (e.g., small-molecule and nucleic acid drugs) for subsequent disease treatment. These cell-based DDSs have their own unique in vivo fates, which are attributed to various factors, including their biological properties and functions, the loaded drugs and loading process, physiological and pathological circumstances, and the body's response to these carrier cells, which result in differences in drug delivery efficiency and therapeutic effect. In this review, we summarize the main cell-based DDSs and their biological properties and functions, applications in drug delivery and disease treatment, and in vivo fate and influencing factors. We envision that the unique biological properties, combined with continuing research, will enable development of cell-based DDSs as friendly drug vectors for the safe, effective, and even personalized treatment of diseases.

A modular 3D printed microfluidic system: a potential solution for continuous cell harvesting in large-scale bioprocessing

Microfluidic devices have shown promising applications in the bioprocessing industry. However, the lack of modularity and high cost of testing and error limit their implementation in the industry. Advances in 3D printing technologies have facilitated the conversion of microfluidic devices from research output to applicable industrial systems. Here, for the first time, we presented a 3D printed modular microfluidic system consisting of two micromixers, one spiral microfluidic separator, and one microfluidic concentrator. We showed that this system can detach and separate mesenchymal stem cells (MSCs) from microcarriers (MCs) in a short time while maintaining the cell's viability and functionality. The system can be multiplexed and scaled up to process large volumes of the industry. Importantly, this system is a closed system with no human intervention and is promising for current good manufacturing practices.

Efficacy and Safety of Mesenchymal Stem Cell Transplantation in the Treatment of Autoimmune Diseases (Rheumatoid Arthritis, Systemic Lupus Erythematosus, Inflammatory Bowel Disease, Multiple Sclerosis, and Ankylosing Spondylitis): A Systematic Review and Meta-Analysis of Randomized Controlled Trial

Objective

To evaluate the efficacy and safety of mesenchymal stem cell (MSC) transplantation in the treatment of autoimmune diseases.

Methods

The Chinese and English databases were searched for clinical research on the treatment of autoimmune diseases with mesenchymal stem cells. The search time range is from a self-built database to October 1, 2021. Two reviewers independently screened the literature according to the inclusion and exclusion criteria, extracted data, and evaluated the bias of the included studies. RevMan 5.3 analysis software was used for meta-analysis.

Results

A total of 18 RCTs involving 5 autoimmune diseases were included. The 5 autoimmune disease were rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), inflammatory bowel disease, ankylosing spondylitis, and multiple sclerosis. For RA, the current randomized controlled trials (RCTs) still believe that stem cell transplantation may reduce disease activity, improve the clinical symptoms (such as DAS28), and the percentage of CD4+CD 25+Foxp3+Tregs in the response group increased and the percentage of CD4+IL-17A+Th17 cells decreased. The total clinical effective rate of RA is 54%. For SLE, the results showed that mesenchymal stem cell transplantation may improve SLEDAI [-2.18 (-3.62, -0.75), P = 0.003], urine protein [-0.93 (-1.04, -0.81), P < 0.00001], and complement C3 [0.31 (0.19, 0.42), P < 0.00001]. For inflammatory bowel disease, the results showed that mesenchymal stem cell transplantation may improve clinical efficacy [2.50 (1.07, 5.84), P = 0.03]. For ankylosing spondylitis, MSC treatment for 6 months may increase the total effective rate; reduce erythrocyte sedimentation rate, intercellular adhesion molecules, and serum TNF-α; and improve pain and activity. For multiple sclerosis, the current research results are still controversial, so more RCTs are needed to amend or confirm the conclusions. No obvious adverse events of mesenchymal stem cell transplantation were found in all RCTs.

Conclusion

MSCs have a certain effect on different autoimmune diseases, but more RCTs are needed to further modify or confirm the conclusion.

Human MuStem cells repress T-cell proliferation and cytotoxicity through both paracrine and contact-dependent pathways

Background

Muscular dystrophies (MDs) are inherited diseases in which a dysregulation of the immune response exacerbates disease severity and are characterized by infiltration of various immune cell types leading to muscle inflammation, fiber necrosis and fibrosis. Immunosuppressive properties have been attributed to mesenchymal stem cells (MSCs) that regulate the phenotype and function of different immune cells. However, such properties were poorly considered until now for adult stem cells with myogenic potential and advanced as possible therapeutic candidates for MDs. In the present study, we investigated the immunoregulatory potential of human MuStem (hMuStem) cells, for which we previously demonstrated that they can survive in injured muscle and robustly counteract adverse tissue remodeling.

Methods

The impact of hMuStem cells or their secretome on the proliferative and phenotypic properties of T-cells was explored by co-culture experiments with either peripheral blood mononucleated cells or CD3-sorted T-cells. A comparative study was produced with the bone marrow (BM)-MSCs. The expression profile of immune cell-related markers on hMuStem cells was determined by flow cytometry while their secretory profile was examined by ELISA assays. Finally, the paracrine and cell contact-dependent effects of hMuStem cells on the T-cell-mediated cytotoxic response were analyzed through IFN-γ expression and lysis activity.

Results

Here, we show that hMuStem cells have an immunosuppressive phenotype and can inhibit the proliferation and the cytotoxic response of T-cells as well as promote the generation of regulatory T-cells through direct contact and via soluble factors. These effects are associated, in part, with the production of mediators including heme-oxygenase-1, leukemia inhibitory factor and intracellular cell adhesion molecule-1, all of which are produced at significantly higher levels by hMuStem cells than BM-MSCs. While the production of prostaglandin E2 is involved in the suppression of T-cell proliferation by both hMuStem cells and BM-MSCs, the participation of inducible nitric oxide synthase activity appears to be specific to hMuStem cell-mediated one.

Conclusions

Together, our findings demonstrate that hMuStem cells are potent immunoregulatory cells. Combined with their myogenic potential, the attribution of these properties reinforces the positioning of hMuStem cells as candidate therapeutic agents for the treatment of MDs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02681-3.

In Vitro Cellular and Molecular Interplay between Human Foreskin-Derived Mesenchymal Stromal/Stem Cells and the Th17 Cell Pathway

Foreskin, considered a biological waste material, has been shown to be a reservoir of therapeutic cells. The immunomodulatory properties of mesenchymal stromal/stem cells (MSCs) from the foreskin (FSK-MSCs) are being evaluated in cell-based therapy for degenerative, inflammatory and autoimmune disorders. Within the injured/inflamed tissue, proinflammatory lymphocytes such as IL-17-producing T helper cells (Th17) may interact with the stromal microenvironment, including MSCs. In this context, MSCs may encounter different levels of T cells as well as specific inflammatory signals. Uncovering the cellular and molecular changes during this interplay is central for developing an efficient and safe immunotherapeutic tool. To this end, an in vitro human model of cocultures of FSK-MSCs and T cells was established. These cocultures were performed at different cell ratios in the presence of an inflammatory setting. After confirming that FSK-MSCs respond to ISCT criteria by showing a typical phenotype and multilineage potential, we evaluated by flow cytometry the expression of Th17 cell markers IL-17A, IL23 receptor and RORγt within the lymphocyte population. We also measured 15 human Th17 pathway-related cytokines. Regardless of the T cell/MSC ratio, we observed a significant increase in IL-17A expression associated with an increase in IL-23 receptor expression. Furthermore, we observed substantial modulation of IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, INF-γ, sCD40, and TNF-α secretion. These findings suggest that FSK-MSCs are receptive to their environment and modulate the T cell response accordingly. The changes within the secretome of the stromal and immune environment are likely relevant for the therapeutic effect of MSCs. FSK-MSCs represent a valuable cellular product for immunotherapeutic purposes that needs to be further clarified and developed.

Mesenchymal Stem/Stromal Cells as a Vehicle for Cytokine Delivery: An Emerging Approach for Tumor Immunotherapy

Pro-inflammatory cytokines can effectively be used for tumor immunotherapy, affecting every step of the tumor immunity cycle. Thereby, they can restore antigen priming, improve the effector immune cell frequencies in the tumor microenvironment (TME), and eventually strengthen their cytolytic function. A renewed interest in the anticancer competencies of cytokines has resulted in a substantial promotion in the number of trials to address the safety and efficacy of cytokine-based therapeutic options. However, low response rate along with the high toxicity associated with high-dose cytokine for reaching desired therapeutic outcomes negatively affect their clinical utility. Recently, mesenchymal stem/stromal cells (MSCs) due to their pronounced tropism to tumors and also lower immunogenicity have become a promising vehicle for cytokine delivery for human malignancies. MSC-based delivery of the cytokine can lead to the more effective immune cell-induced antitumor response and provide sustained release of target cytokines, as widely evidenced in a myriad of xenograft models. In the current review, we offer a summary of the novel trends in cytokine immunotherapy using MSCs as a potent and encouraging carrier for antitumor cytokines, focusing on the last two decades' animal reports.

Clinical experience on umbilical cord mesenchymal stem cell treatment in 210 severe and critical COVID-19 cases in Turkey

Objective

Treatment for COVID-19 is still urgent need for the critically ill and severe cases. UC-MSC administration has a therapeutic benefit for severe COVID-19 patients even in the recovery period. In this paper, we aimed to present our clinical experience with UC-MSC treatment in severe and critical severe COVID-19 patients.

Methods

In this study we evaluated the clinical outcome of severe/critically severe 210 COVID-19 patients treated with UC-MSCs, 1–2 × 10⁶ per kilogram to 210 patients from 15/10/2020 until 25/04/2021.

Results

Out of 99 critically severe intubated patients we have observed good clinical progress/discharged from ICU in 52 (52.5%) patients. Where as 86 (77.5%) of 111 severe unintubated patients discharged from ICU. Intubated 47 (47.5%) patients and unintubated 25 (22.5%) patients pass away. Significantly higher survival was observed in patients who underwent UC-MSCs before intubation (OR = 1.475, 95% CI = 1.193–1.824 p < 0.001). It was observed that the SaO₂ parameter tended to improve after UC-MSC therapy compared to all groups. But SaO₂ parameter between intubated and unintubated groups was not statistically significant (p > 0.05), while in discharged cases SaO₂ parameter was statistically significant (p = 0.01). Besides, there was a statistically significant relation with intubation status, age (OR = 3.868, 95% CI = 0.574–7.152 p = 0.02) and weigh (OR = 6.768, 95% CI = 3.423–10.112 p < 0.001) thus presented an elevated risk for COVID-19. The linear regression analysis confirmed that the high weight was associated with the risk of intubation in COVID-19 (p = 0.001).

Conclusions

According to our results and from recent studies, UC-MSC treatment is safe with high potential to be used as an added therapeutic treatment for severe COVID-19 patients. Our experience showed that UC-MSC therapy may restore oxygenation and downregulate cytokine storm in patients hospitalized with severe COVID-19. We advice wider randomised studies to discover the detailed therapeutic pathophysiology of the MSCs on COVID-19 patients.

Graphical abstract

MSCs transplantation improves the damaging effects of the cytokine storm through immunomodulation and improving tissue and organ repair. Severe patients who were unintubated were in the Phase I, while critical patients who were intubated were in the Phase II. The figure is created via biorender application, (BioRender.com).

Mesenchymal Stem/Stromal Cell-Based Delivery: A Rapidly Evolving Strategy for Cancer Therapy

Mesenchymal stem/stromal cell (MSC)-based therapy has become an attractive and advanced scientific research area in the context of cancer therapy. This interest is closely linked to the MSC-marked tropism for tumors, suggesting them as a rational and effective vehicle for drug delivery for both hematological and solid malignancies. Nonetheless, the therapeutic application of the MSCs in human tumors is still controversial because of the induction of several signaling pathways largely contributing to tumor progression and metastasis. In spite of some evidence supporting that MSCs may sustain cancer pathogenesis, increasing proofs have indicated the suppressive influences of MSCs on tumor cells. During the last years, a myriad of preclinical and some clinical studies have been carried out or are ongoing to address the safety and efficacy of the MSC-based delivery of therapeutic agents in diverse types of malignancies. A large number of studies have focused on the MSC application as delivery vehicles for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), chemotherapeutic drug such as gemcitabine (GCB), paclitaxel (PTX), and doxorubicin (DOX), prodrugs such as 5-fluorocytosine (5-FC) and ganciclovir (GCV), and immune cell-activating cytokines along with oncolytic virus. In the current review, we evaluate the latest findings rendering the potential of MSCs to be employed as potent gene/drug delivery vehicle for inducing tumor regression with a special focus on the in vivo reports performed during the last two decades.

Stem Cells Therapy as a Possible Therapeutic Option in Treating COVID-19 Patients

An unfortunate emergence of a new virus SARS-CoV-2, causing a disease known as COVID-19, has spread all around the globe and has caused a pandemic. It primarily affects the respiratory tract and lungs in some cases causing severe organ damage and pneumonia due to overwhelming immune responses. Clinical reports show that the most commons symptoms are fever, dry cough, and shortness of breath, along with several other symptoms. It is thought that an immense cytokine dysregulation in COVID-19 patients is caused following the virus infection. Notably, if patients present with pre-existing specific comorbidities like diabetes or high blood pressure, rates of COVID-19 induced complications and deaths are escalated. Mesenchymal stem cell (MSC) therapy has been shown to alleviate pneumonia and acute respiratory syndrome (ARDS) symptoms, through their immunomodulatory activities in COVID-19 patients. Although more research studies and clinical trial results are needed to elucidate the exact mechanism by which MSCs provide relief to COVID-19 infected patients. Results from clinical trials are encouraging as patients treated with MSCs, regain lung functions and have restored levels of cytokines and trophic factors underscoring the fact that stem cell therapy can be, at least, a complementary therapy to alleviate sufferings in COVID-19 patients. This review discusses the possible therapeutic uses of MSCs for treating COVID-19. Graphical Abstract.

Mesenchymal Stromal Cells Rapidly Suppress TCR Signaling-Mediated Cytokine Transcription in Activated T Cells Through the ICAM-1/CD43 Interaction

Cell-cell contact participates in the process of mesenchymal stromal cell (MSC)-mediated T cell modulation and thus contributes to MSC-based therapies for various inflammatory diseases, especially T cell-mediated diseases. However, the mechanisms underlying the adhesion interactions between MSCs and T cells are still poorly understood. In this study, we explored the interaction between MSCs and T cells and found that activated T cells could rapidly adhere to MSCs, leading to significant reduction of TNF-α and IFN-γ mRNA expression. Furthermore, TCR-proximal signaling in activated T cells was also dramatically suppressed in the MSC co-culture, resulting in weakened Ca²⁺ signaling. MSCs rapidly suppressed TCR signaling and its downstream signaling in a cell-cell contact-dependent manner, partially through the ICAM-1/CD43 adhesion interaction. Blockade of either ICAM-1 on MSCs or CD43 on T cells significantly reversed this rapid suppression of proinflammatory cytokine expression in T cells. Mechanistically, MSC-derived ICAM-1 likely disrupts CD43-mediated TCR microcluster formation to limit T cell activation. Taken together, our results reveal a fast mechanism of activated T cell inhibition by MSCs, which provides new clues to unravel the MSC-mediated immunoregulatory mechanism for aGVHD and other severe acute T cell-related diseases.

Neural crest-like stem cells for tissue regeneration

Neural crest stem cells (NCSCs) are a transient population of cells that arise during early vertebrate development and harbor stem cell properties, such as self‐renewal and multipotency. These cells form at the interface of non‐neuronal ectoderm and neural tube and undergo extensive migration whereupon they contribute to a diverse array of cell and tissue derivatives, ranging from craniofacial tissues to cells of the peripheral nervous system. Neural crest‐like stem cells (NCLSCs) can be derived from pluripotent stem cells, placental tissues, adult tissues, and somatic cell reprogramming. NCLSCs have a differentiation capability similar to NCSCs, and possess great potential for regenerative medicine applications. In this review, we present recent developments on the various approaches to derive NCLSCs and the therapeutic application of these cells for tissue regeneration.

Mesenchymal stem cells as a double-edged sword in tumor growth: focusing on MSC-derived cytokines

Mesenchymal stem cells (MSCs) show homing capacity towards tumor sites. Numerous reports indicate that they are involved in multiple tumor-promoting processes through several mechanisms, including immunosuppression; stimulation of angiogenesis; transition to cancer-associated fibroblasts; inhibition of cancer cell apoptosis; induction of epithelial-mesenchymal transition (EMT); and increase metastasis and chemoresistance. However, other studies have shown that MSCs suppress tumor growth by suppressing angiogenesis, incrementing inflammatory infiltration, apoptosis and cell cycle arrest, and inhibiting the AKT and Wnt signaling pathways. In this review, we discuss the supportive and suppressive impacts of MSCs on tumor progression and metastasis. We also discuss MSC-based therapeutic strategies for cancer based on their potential for homing to tumor sites.

Single-cell profiles of human bone marrow-derived mesenchymal stromal cells after IFN-γ and TNF-α licensing

BACKGROUND

Pre-licensing mesenchymal stromal cells (MSCs) with IFN-γ and TNF-α can empower their immune fate and induce a more effective immune regulation. However, the cellular heterogeneity of MSCs limits our understanding of this inflammatory licensing.

METHODS

The publicly available Gene Expression Omnibus single-cell RNA sequencing (scRNA-seq) data of human bone marrow-derived MSCs with or without IFN-γ and TNF-α licensing were analyzed. Based on the scRNA-seq data and related marker genes, the cell-cycle, stemness, differentiative potencies, and immunomodulate capability of unlicensed and licensed MSCs were compared.

RESULTS

After removing low-quality cells and regressing out the ribosomal gene effects, high-quality data reflecting IFN-γ and TNF-α effect on MSCs were chosen for further analysis. Despite the heterogeneity, pre-licensing didn't influence the cell-cycle and stemness of human bone marrow-derived MSCs. The osteogenesis potencies were decreased, the chondrogenesis potencies were increased while the adipogenesis potencies were stable in licensed MSCs. Licensed MSCs also showed more effective immunomodulate capability including expression of related chemokines, cytokines, surface molecules, and receptors.

CONCLUSION

Collectively, our study showed the expression profiles of human bone marrow-derived unlicensed and licensed MSCs about the cell cycle, stemness, differentiative potencies, and immunomodulate capability at single-cell resolution, which may help the comprehensive understanding about the inflammatory licensing of human bone marrow-derived MSCs and their further clinical application.

Mesenchymal stem cells as a multimodal treatment for nervous system diseases

Neurological disorders are a massive challenge for modern medicine. Apart from the fact that this group of diseases is the second leading cause of death worldwide, the majority of patients have no access to any possible effective and standardized treatment after being diagnosed, leaving them and their families helpless. This is the reason why such great emphasis is being placed on the development of new, more effective methods to treat neurological patients. Regenerative medicine opens new therapeutic approaches in neurology, including the use of cell-based therapies. In this review, we focus on summarizing one of the cell sources that can be applied as a multimodal treatment tool to overcome the complex issue of neurodegeneration-mesenchymal stem cells (MSCs). Apart from the highly proven safety of this approach, beneficial effects connected to this type of treatment have been observed. This review presents modes of action of MSCs, explained on the basis of data from vast in vitro and preclinical studies, and we summarize the effects of using these cells in clinical trial settings. Finally, we stress what improvements have already been made to clarify the exact mechanism of MSCs action, and we discuss potential ways to improve the introduction of MSC-based therapies in clinics. In summary, we propose that more insightful and methodical optimization, by combining careful preparation and administration, can enable use of multimodal MSCs as an effective, tailored cell therapy suited to specific neurological disorders.

Inflammatory niche: Mesenchymal stromal cell priming by soluble mediators

Mesenchymal stromal/stem cells (MSCs) are adult stem cells of stromal origin that possess self-renewal capacity and the ability to differentiate into multiple mesodermal cell lineages. They play a critical role in tissue homeostasis and wound healing, as well as in regulating the inflammatory microenvironment through interactions with immune cells. Hence, MSCs have garnered great attention as promising candidates for tissue regeneration and cell therapy. Because the inflammatory niche plays a key role in triggering the reparative and immunomodulatory functions of MSCs, priming of MSCs with bioactive molecules has been proposed as a way to foster the therapeutic potential of these cells. In this paper, we review how soluble mediators of the inflammatory niche (cytokines and alarmins) influence the regenerative and immunomodulatory capacity of MSCs, highlighting the major advantages and concerns regarding the therapeutic potential of these inflammatory primed MSCs. The data summarized in this review may provide a significant starting point for future research on priming MSCs and establishing standardized methods for the application of preconditioned MSCs in cell therapy.

Transcriptome profiles acquired during cell expansion and licensing validate mesenchymal stromal cell lineage genes

Background

Mesenchymal stromal cells (MSCs) are rapidly advancing as commercial therapeutics. However, there are still no adequate tools to validate the identity of MSCs and support standardization of MSC-based products. Currently accepted metrics include cell surface marker profiling and tri-lineage differentiation assays, neither of which is definitive. Transcript profiling represents a cost- and time-effective approach amenable to MSC manufacturing processes. Two independent labs recently reported non-overlapping MSC-specific transcriptomic signatures of 489 and 16 genes.

Methods

Here, we interrogated our repository of transcriptome data to determine whether routine culture manipulations including cell expansion and immune activation affect expression of the reported MSC lineage genes. These data sets comprise 4 donor populations of human umbilical cord (UC) MSCs serially cultured from cryopreservation thaw through pre-senescence, and 3 donor populations each of naïve UC and bone marrow (BM) MSCs and licensed by 3 different cytokines.

Results

Overall, 437 of 456 proposed signature genes assessed in these data sets were reliably expressed, representing an enduring lineage profile in 96% agreement with the previous studies. Serial passaging resulted in the downregulation of 3 signature genes, and one was silenced. Cytokine stimulation downregulated expression of 16 signature genes, and 3 were uniformly silenced in one or the other MSC type. Fifteen additional genes were unreliably detected, independent of culture manipulation.

Conclusion

These results validate and refine the proposed transcriptomic tools for reliable identification of MSCs after isolation through cell expansion and after inflammatory activation. We propose a 24-gene signature to support standardized and accessible MSC characterization.

Role of MSC in the Tumor Microenvironment

The tumor microenvironment represents a dynamically composed matrix in which tissue-associated cancer cells are embedded together with a variety of further cell types to form a more or less separate organ-like structure. Constantly mutual interactions between cells of the tumor microenvironment promote continuous restructuring and growth in the tumor. A distinct organization of the tumor stroma also facilitates the formation of transient cancer stem cell niches, thereby contributing to progressive and dynamic tumor development. An important but heterogeneous mixture of cells that communicates among the cancer cells and the different tumor-associated cell types is represented by mesenchymal stroma-/stem-like cells (MSC). Following recruitment to tumor sites, MSC can change their functionalities, adapt to the tumor's metabolism, undergo differentiation and synergize with cancer cells. Vice versa, cancer cells can alter therapeutic sensitivities and change metastatic behavior depending on the type and intensity of this MSC crosstalk. Thus, close cellular interactions between MSC and cancer cells can eventually promote cell fusion by forming new cancer hybrid cells. Consequently, newly acquired cancer cell functions or new hybrid cancer populations enlarge the plasticity of the tumor and counteract successful interventional strategies. The present review article highlights some important features of MSC within the tumor stroma.

Intra-articular injection of hUC-MSCs expressing miR-140-5p induces cartilage self-repairing in the rat osteoarthritis

INTRODUCTION

Currently, osteoarthritis (OA) receives global increasing attention because it associates severe joint pain and serious disability. Stem cells intra-articular injection therapy showed a potential therapeutic superiority to reduce OA development and to improve treating outputs. However, the long-term effect of stem cells intra-articular injection on the cartilage regeneration remains unclear. Recently, miR-140-5p was confirmed as a critical positive regulator in chondrogenesis. We hypothesized that hUC-MSCs overexpressing miR-140-5p have better therapeutic effect on osteoarthritis.

MATERIALS AND METHODS

To enhance stem cell chondrogenic differentiation, we have transfected human umbilical cord mesenchymal stem cells (hUC-MSCs) with miR-140-5p mimics and miR-140-5p lentivirus to overexpress miR-140-5p in a short term or a long term accordingly. Thereafter, MSCs proliferation, chondrogenic genes expression and extracellular matrix were assessed. Destabilization of the medial meniscus (DMM) surgery was performed on the knee joints of SD rats as an OA model, and then intra-articular injection of hUC-MSCs or hUC-MSCs transfected with miR-140-5p lentivirus was carried to evaluate the cartilage healing effect with histological staining and OARSI scores. The localization of hUC-MSCs after intra-articular injection was further confirmed by immunohistochemical staining.

RESULTS

Significant induction of chondrogenic differentiation in the miR-140-5p-hUC-MSCs (140-MSCs), while its proliferation was not influenced. Interestingly, intra-articular injection of 140-MSCs significantly enhanced articular cartilage self-repairing in comparison to normal hUC-MSCs. Moreover, we noticed that intra-articular injection of high 140-MSCs numbers reinforces cells assembling on the impaired cartilage surface and subsequently differentiated into chondrocytes.

CONCLUSIONS

In conclusion, these results indicate therapeutic superiority of hUC-MSCs overexpressing miR-140-5p to treat OA using intra-articular injection.

Inflammatory priming enhances mesenchymal stromal cell secretome potential as a clinical product for regenerative medicine approaches through secreted factors and EV-miRNAs: the example of joint disease

BACKGROUND

Mesenchymal stromal cell (MSC)-enriched products showed positive clinical outcomes in regenerative medicine, where tissue restoration and inflammation control are needed. GMP-expanded MSCs displayed an even higher potential due to exclusive secretion of therapeutic factors, both free and conveyed within extracellular vesicles (EVs), collectively termed secretome. Moreover, priming with biochemical cues may influence the portfolio and biological activities of MSC-derived factors. For these reasons, the use of naive or primed secretome gained attention as a cell-free therapeutic option. Albeit, at present, a homogenous and comprehensive secretome fingerprint is still missing. Therefore, the aim of this work was to deeply characterize adipose-derived MSC (ASC)-secreted factors and EV-miRNAs, and their modulation after IFNγ preconditioning. The crucial influence of the target pathology or cell type was also scored in osteoarthritis to evaluate disease-driven potency.

METHODS

ASCs were isolated from four donors and cultured with and without IFNγ. Two-hundred secreted factors were assayed by ELISA. ASC-EVs were isolated by ultracentrifugation and validated by flow cytometry, transmission electron microscopy, and nanoparticle tracking analysis. miRNome was deciphered by high-throughput screening. Bioinformatics was used to predict the modulatory effect of secreted molecules on pathologic cartilage and synovial macrophages based on public datasets. Models of inflammation for both macrophages and chondrocytes were used to test by flow cytometry the secretome anti-inflammatory potency.

RESULTS

Data showed that more than 60 cytokines/chemokines could be identified at varying levels of intensity in all samples. The vast majority of factors are involved in extracellular matrix remodeling, and chemotaxis or motility of inflammatory cells. IFNγ is able to further increase the capacity of the secretome to stimulate cell migration signals. Moreover, more than 240 miRNAs were found in ASC-EVs. Sixty miRNAs accounted for > 95% of the genetic message that resulted to be chondro-protective and M2 macrophage polarizing. Inflammation tipped the balance towards a more pronounced tissue regenerative and anti-inflammatory phenotype. In silico data were confirmed on inflamed macrophages and chondrocytes, with secretome being able to increase M2 phenotype marker CD163 and reduce the chondrocyte inflammation marker VCAM1, respectively. IFNγ priming further enhanced secretome anti-inflammatory potency.

CONCLUSIONS

Given the portfolio of soluble factors and EV-miRNAs, ASC secretome showed a marked capacity to stimulate cell motility and modulate inflammatory and degenerative processes. Preconditioning is able to increase this ability, suggesting inflammatory priming as an effective strategy to obtain a more potent clinical product which use should always be driven by the molecular mark of the target pathology.

The Impact of Cell-Expansion and Inflammation on The Immune-Biology of Human Adipose Tissue-Derived Mesenchymal Stromal Cells

Background: As a cell-based therapeutic, AT-MSCs need to create an immuno-reparative environment appropriate for tissue repair. In the presence of injury, MSCs may have to proliferate and face inflammation. Clinical application requires repeated administrations of a high number of cells with a well-established immune profile. Methods: We have established an immuno-comparative screening by determining the expression of 28 molecules implicated in immune regulation. This screening was performed during cell-expansion and inflammatory priming of AT-MSCs. Results: Our study confirms that AT-MSCs are highly expandable and sensitive to inflammation. Both conditions have substantially modulated the expression of a panel of immunological marker. Specifically, CD34 expression was substantially decreased upon cell-passaging. HLA-ABC, CD40 CD54, CD106, CD274 and CD112 were significantly increased by inflammation. In vitro cell-expansion also significantly altered the expression profile of HLA-DR, CD40, CD62L, CD106, CD166, HLA-G, CD200, HO-1, CD155 and ULBP-3. Conclusion: This study points out the response and characteristics of MSCs following expansion and inflammatory priming. It will strength our knowledge about the molecular mechanisms that may improve or hamper the therapeutic potential of MSCs. These immunological changes need to be further characterized to guarantee a safe cellular product with consistent quality and high therapeutic efficacy.

Immunomodulatory effects of interferon-γ on human fetal cardiac mesenchymal stromal cells

BACKGROUND

Mesenchymal stromal cells (MSCs), due to their regenerative and immunomodulatory properties, are therapeutically used for diseases, including heart failure. As early gestational-phase embryonic tissues exhibit extraordinary regenerative potential, fetal MSCs exposed to inflammation offer a unique opportunity to evaluate molecular mechanisms underlying preferential healing, and investigate their inherent abilities to communicate with the immune system during development. The principal aim of this study was to evaluate the effects of interferon-γ (IFNγ) on the immunomodulatory effects of first-trimester human fetal cardiac (hfc)-MSCs.

METHODS

hfcMSCs (gestational week 8) were exposed to IFNγ, with subsequent analysis of the whole transcriptome, based on RNA sequencing. Exploration of surface-expressed immunoregulatory mediators and modulation of T cell responses were performed by flow cytometry. Presence and activity of soluble mediators were assessed by ELISA or high-performance liquid chromatography.

RESULTS

Stimulation of hfcMSCs with IFNγ revealed significant transcriptional changes, particularly in respect to the expression of genes belonging to antigen presentation pathways, cell cycle control, and interferon signaling. Expression of immunomodulatory genes and associated functional changes, including indoleamine 2,3-dioxygenase activity, and regulation of T cell activation and proliferation via programmed cell death protein (PD)-1 and its ligands PD-L1 and PD-L2, were significantly upregulated. These immunoregulatory molecules diminished rapidly upon withdrawal of inflammatory stimulus, indicating a high degree of plasticity by hfcMSCs.

CONCLUSIONS

To our knowledge, this is the first study performing a systematic evaluation of inflammatory responses and immunoregulatory properties of first-trimester cardiac tissue. In summary, our study demonstrates the dynamic responsiveness of hfcMSCs to inflammatory stimuli. Further understanding as to the immunoregulatory properties of hfcMSCs may be of benefit in the development of novel stromal cell therapeutics for cardiovascular disease.

Human Hepatocytes and Differentiated Adult-Derived Human Liver Stem/Progenitor Cells Display In Vitro Immunosuppressive Properties Mediated, at Least in Part, through the Nonclassical HLA Class I Molecule HLA-G

One of the main challenges in liver cell therapy (LCT) is the induction of a tolerogenic microenvironment to promote graft acceptance in the recipient. Little is known about the immunomodulatory potential of the hepatic cells used in liver cell therapy. In this work, we wanted to evaluate the immunosuppressive properties of human hepatocytes and adult-derived human liver stem/progenitor cells (ADHLSCs), as well as the potential involvement of the immunomodulatory molecule HLA-G. We demonstrated that both cell types were capable of inhibiting the proliferative response of PBMCs to an allogenic stimulus and that the immune inhibitory potential of ADHLSCs, although lower than that of hepatocytes, increased after hepatogenic differentiation. We demonstrated that liver cells express HLA-G and that the immune inhibition pattern was clearly associated to its expression. Interestingly, HLA-G expression increased after the third step of differentiation, wherein oncostatin M (OSM) was added. A 48 hr treatment with OSM was sufficient to induce HLA-G expression in ADHLSCs and result in immune inhibition. Surprisingly, blocking HLA-G partially reversed the immune inhibition mediated by hepatocytes and differentiated ADHLSCs, but not that of undifferentiated ADHLSCs, suggesting that additional immune inhibitory mechanisms may be used by these cells. In conclusion, we demonstrated that both hepatocytes and ADHLSCs present immunomodulatory properties mediated, at least in part, through HLA-G, which can be upregulated following hepatogenic differentiation or liver cell pretreatment with OSM. These observations open up new perspectives for the induction of tolerance following LCT and for potential therapeutic applications of these liver cells.

ER-stressed MSC displayed more effective immunomodulation in RA CD4+CXCR5+ICOS+ follicular helper-like T cells through higher PGE2 binding with EP2/EP4

Objectives: To analyze the further immunomodulatory effects of endoplasmic reticulum (ER)-stressed umbilical cord-derived mesenchymal stem cells MSCs (UC-MSCs) on rheumatoid arthritis (RA) CD4⁺CXCR5⁺ICOS⁺ T (follicular helper-like T, Tfh) cells.Methods: MSCs were isolated from umbilical cord and surface markers were identified by flow cytometry. CD4⁺ T cells were purified from RA patients' peripheral blood mononuclear cells (PBMCs) using immunomagnetic beads. Thapsigargin (Tg)-stimulated or unstimulated MSCs were co-cultured with RA CD4⁺ T cells. CD4⁺CXCR5⁺ICOS⁺ T cells were analyzed with fluorescence activating cell sorter (FACS) and major soluble factors secreted by MSCs were detected by qRT-PCR as well as ELISA. Receptors of prostanoid E2 (PGE2), known as EP1-4, on CD4⁺ T cells were tested with RT-PCR and FACS. Proportion of CD4⁺CXCR5⁺ICOS⁺ T cells was determined after EP2/EP4 antagonists and anti-IL-6R antibody was added into co-cultured system, respectively.Results: ER-stressed MSCs further down-regulated peripheral CD4⁺CXCR5⁺ICOS⁺ T cells compared with Tg-stimulated MSCs and CD4⁺ T co-cultured group. PGE2 and IL-6 increased obviously in the supernatants. EP2/EP4 could be detected on CD4⁺ T cells and frequencies of CD4⁺CXCR5⁺ICOS⁺ T cells were upregulated when EP2 and/or EP4 antagonists rather than anti-IL-6R antibody were added.Conclusions: ER-stressed MSCs exhibited better inhibition effect on RA CD4⁺CXCR5⁺ICOS⁺ T cells by releasing PGE2, indicating the immunosuppressive effect of MSCs could be enhanced by induction of ER stress.

Mesenchymal Stromal Cell-Based Therapy: New Perspectives and Challenges

Stem cells have been the focus of intense research opening up new possibilities for the treatment of various diseases. Mesenchymal stromal cells (MSCs) are multipotent cells with relevant immunomodulatory properties and are thus considered as a promising new strategy for immune disease management. To enhance their efficiency, several issues related to both MSC biology and functions are needed to be identified and, most importantly, well clarified. The sources from which MSCs are isolated are diverse and might affect their properties. Both clinicians and scientists need to handle a phenotypic-characterized population of MSCs, particularly regarding their immunological profile. Moreover, it is now recognized that the tissue-reparative effects of MSCs are based on their immunomodulatory functions that are activated following a priming/licensing step. Thus, finding the best ways to pre-conditionate MSCs before their injection will strengthen their activity potential. Finally, soluble elements derived from MSC-secretome, including extracellular vesicles (EVs), have been proposed as a cell-free alternative tool for therapeutic medicine. Collectively, these features have to be considered and developed to ensure the efficiency and safety of MSC-based therapy. By participating to this Special Issue “Mesenchymal Stem/Stromal Cells in Immunity and Disease”, your valuable contribution will certainly enrich the content and discussion related to the thematic of MSCs.

Metabolism in Human Mesenchymal Stromal Cells: A Missing Link Between hMSC Biomanufacturing and Therapy?

Human mesenchymal stem cells (hMSCs) are the most commonly-tested adult stem cells in cell therapy. While the initial focus for hMSC clinical applications was to exploit their multi-potentiality for cell replacement therapies, it is now apparent that hMSCs empower tissue repair primarily by secretion of immuno-regulatory and pro-regenerative factors. A growing trend in hMSC clinical trials is the use of allogenic and culture-expanded cells because they are well-characterized and can be produced in large scale from specific donors to compensate for the donor pathological condition(s). However, donor morbidity and large-scale expansion are known to alter hMSC secretory profile and reduce therapeutic potency, which are significant barriers in hMSC clinical translation. Therefore, understanding the regulatory mechanisms underpinning hMSC phenotypic and functional property is crucial for developing novel engineering protocols that maximize yield while preserving therapeutic potency. hMSC are heterogenous at the level of primary metabolism and that energy metabolism plays important roles in regulating hMSC functional properties. This review focuses on energy metabolism in regulating hMSC immunomodulatory properties and its implication in hMSC sourcing and biomanufacturing. The specific characteristics of hMSC metabolism will be discussed with a focus on hMSC metabolic plasticity and donor- and culture-induced changes in immunomodulatory properties. Potential strategies of modulating hMSC metabolism to enhance their immunomodulation and therapeutic efficacy in preclinical models will be reviewed.

Priming approaches to improve the efficacy of mesenchymal stromal cell-based therapies

Multipotent mesenchymal stromal cells (MSC) have been widely explored for cell-based therapy of immune-mediated, inflammatory, and degenerative diseases, due to their immunosuppressive, immunomodulatory, and regenerative potentials. Preclinical studies and clinical trials have demonstrated promising therapeutic results although these have been somewhat limited. Aspects such as low in vivo MSC survival in inhospitable disease microenvironments, requirements for ex vivo cell overexpansion prior to infusions, intrinsic differences between MSC and different sources and donors, variability of culturing protocols, and potency assays to evaluate MSC products have been described as limitations in the field. In recent years, priming approaches to empower MSC have been investigated, thereby generating cellular products with improved potential for different clinical applications. Herein, we review the current priming approaches that aim to increase MSC therapeutic efficacy. Priming with cytokines and growth factors, hypoxia, pharmacological drugs, biomaterials, and different culture conditions, as well as other diverse molecules, are revised from current and future perspectives.

Manufacturing of human Wharton's jelly stem cells for clinical use: selection of serum is important

BACKGROUND

Human Wharton's jelly-derived mesenchymal stromal cells (hWJSCs) have gained considerable attention for their use in cell therapy. Many of these applications would require manufacturing of millions of hWJSCs. It is, therefore, necessary to develop a Good Manufacturing Practice (GMP)-compliant hWJSC expansion protocol, allowing the generation of a large quantity of cells to meet both clinical and regulatory requirements. Here, we compared human platelet lysate (HPL) and human serum (HS) in supporting clinical-grade hWJSC expansion.

METHODS

hWJSCs were successfully isolated from six different umbilical cords using GMP-compliant dissociation enzymes. Freshly isolated hWJSCs were cultured in media supplemented with 10% of one of the following sera: fetal bovine serum (FBS), HPL and HS. Properties of the expanded hWJSCs were analyzed.

RESULTS

We showed that GMP-compliant dissociation enzymes were as efficient as research-grade dissociation enzymes in isolating hWJSCs. hWJSC fresh cell yield and cell viability using HPL and HS supplementations were at greater advantages than FBS. Moreover, hWJSCs expanded in HPL and HS supplementations not only preserved classical MSCs phenotypes and differentiation potential to adipocytes, osteocytes and chondrocytes, they also enhanced the migration of skin fibroblasts. However, HS, unlike HPL, did not alter immunogenicity properties of hWJSCs. hWJSCs expanded in HS supplementation also exerted greater immunosuppressive action in inhibiting T-cell proliferation and increased extracellular matrix (ECM) gene expression, making them useful in tissue repair clinical application.

CONCLUSION

Our findings indicate that HS can be considered as a promising and safer alternative to FBS, and should be recommended for clinical-grade expansion of hWJSCs.

Immunohematology Mesenchymal Stromal Cell-based Therapy: From Research to Clinic

Mesenchymal stromal cells (MSC) are nonhematopoietic cells that can be isolated from several adult and fetal tissues. MSC present specific features as the capacity to support hematopoiesis and to regulate immune response. Thus, the use of MSC as a cell therapeutic product in the field of immune-hematology is of great importance. In this review, we focused on human MSC and discussed their immune-hematologic properties and their translation toward therapeutic clinical applications. Thus, these features hold great promise for cell-based therapy and are of important relevance for the field.

Mesenchymal stem cells for inflammatory airway disorders: promises and challenges

The regenerative and immunomodulatory characteristics of mesenchymal stem cells (MSCs) make them attractive in the treatment of many diseases. Although they have shown promising preclinical studies of immunomodulation and paracrine effects in inflammatory airway disorders and other lung diseases, there are still challenges that have to be overcome before MSCs can be safely, effectively, and routinely applied in the clinical setting. A good understanding of the roles and mechanisms of the MSC immunomodulatory effects will benefit the application of MSC-based clinical therapy. In this review, we summarize the promises and challenges of the preclinical and clinical trials of MSC therapies, aiming to better understand the role that MSCs play in attempt to treat inflammatory airway disorders.

Aldehyde Dehydrogenase Activity in Adipose Tissue: Isolation and Gene Expression Profile of Distinct Sub-population of Mesenchymal Stromal Cells

Thanks to their relative abundance and easier collection, adipose tissue (AT) is considered an alternative source for the isolation of mesenchymal stromal cells (MSCs). MSCs have great therapeutic values and are thus under investigations for several clinical indications such as regenerative medicine and immunomodulation. In this work, we aimed to identify, isolate and characterize AT-MSCs based on their aldehyde dehydrogenase (ALDH) activity known to be a classical feature of stem cells. FACS technology allowed to isolate two different populations of AT-MSCs according to their ALDH activity (referred as ALDH⁺ and ALDH^-). Depending on their ALDH activity, the transcriptome analysis of both cell populations demonstrated a differential pattern of genes related to the main properties of MSCs (proliferation, response to hypoxia, angiogenesis, phenotype, stemness, multilineage, hematopoiesis, immunomodulation). Based on these profiling, both AT-MSC populations could differ in terms of biological responses and functionalities. Collectively, the use of ALDH for isolating and identifying sub-populations of MSCs with specific gene profile may represent an alternative method to provide solutions for targeted therapeutic applications.

Immunological modulation following bone marrow-derived mesenchymal stromal cells and Th17 lymphocyte co-cultures

OBJECTIVE AND DESIGN

The objective of the study is to uncover the influence of human bone marrow-derived mesenchymal stem cells (BM-MSCs) on the generation of Th17 lymphocytes in co-cultures of both BM-MSCs and T cells.

MATERIALS AND METHODS

BM-MSCs, characterized according to the international society for cellular therapy (ISCT) criteria, were co-cultured with T cells isolated from peripheral blood. The expression levels of IL-17 receptor, RORγt and IL-23 receptor were evaluated using flow cytometry. The levels of cytokines involved in Th17 immunomodulation were measured using multiplex assay.

TREATMENT

Inflammatory primed and non-primed BM-MSCs were co-cultured with either activated or non-activated T cells either at (1/80) and (1/5) ratio respectively.

RESULTS

MSC/T-cell ratio and inflammation significantly influenced the effect of BM-MSCs on the generation of Th17 lymphocytes. Cocultures of either primed or non-primed BM-MSCs with activated T cells significantly induced IL-17A-expressing lymphocytes. Interestingly, the expression of the transcription factor RORγt was significantly increased when compared to levels in activated T cells. Finally, both cell ratio and priming of BM-MSCs with cytokines substantially influenced the cytokine profile of BM-MSCs and T cells.

CONCLUSION

Our findings suggest that BM-MSCs significantly modulate the Th17 lymphocyte pathway in a complex manner.

Empowering the immune fate of bone marrow mesenchymal stromal cells: gene and protein changes

OBJECTIVE AND DESIGN

Bone marrow mesenchymal stromal cells (BM-MSCs) are referred as a promising immunotherapeutic cell product. New approaches using empowered MSCs should be developed as for the treatment or prevention of different immunological diseases. Such preconditioning by new licensing stimuli will empower the immune fate of BM-MSCs and, therefore, promote a better and more efficient biological. Here, our main goal was to establish the immunological profile of BM-MSCs following inflammatory priming and in particular their capacity to adjust their immune-related proteome and transcriptome.

MATERIAL AND METHODS

To run this study, we have used BM-MSC cell cultures, a pro-inflammatory cytokine cocktail priming, flow cytometry analysis, qPCR and ELISA techniques.

RESULTS

Different expression levels of several immunological mediators such as COX-1, COX-2, LIF, HGF, Gal-1, HO-1, IL-11, IL-8, IL-6 and TGF-β were constitutively observed in BM-MSCs. Inflammation priming substantially but differentially modulated the gene and protein expression profiles of these mediators. Thus, expressions of COX-2, LIF, HGF, IL-11, IL-8 and IL-6 were highly increased/induced and those of COX-1, Gal-1, and TGF-β were reduced.

CONCLUSIONS

Collectively, we demonstrated that BM-MSCs are endowed with a specific and modular regulatory machinery which is potentially involved in immunomodulation. Moreover, BM-MSCs are highly sensitive to inflammation and respond to such signal by properly adjusting their gene and protein expression of regulatory factors. Using such preconditioning may empower the immune fate of MSCs and, therefore, enhance their value for cell-based immunotherapy.

Foreskin-derived mesenchymal stromal cells with aldehyde dehydrogenase activity: isolation and gene profiling

Background

Mesenchymal stromal cells (MSCs) become an attractive research topic because of their crucial roles in tissue repair and regenerative medicine. Foreskin is considered as a valuable tissue source containing immunotherapeutic MSCs (FSK-MSCs).

Results

In this work, we used aldehyde dehydrogenase activity (ALDH) assay (ALDEFLUOR™) to isolate and therefore characterize subsets of FSK-MSCs. According to their ALDH activity, we were able to distinguish and sort by fluorescence activated cell sorting (FACS) two subsets of FSK-MSCs (referred as ALDH⁺ and ALDH⁻). Consequently, these subsets were characterized by profiling the gene expression related to the main properties of MSCs (proliferation, response to hypoxia, angiogenesis, phenotype, stemness, multilineage, hematopoiesis and immunomodulation). We thus demonstrated by Real Time PCR several relevant differences in gene expression based on their ALDH activity.

Conclusion

Taken together, this preliminary study suggests that distinct subsets of FSK-MSCs with differential gene expression profiles depending of ALDH activity could be identified. These populations could differ in terms of biological functionalities involving the selection by ALDH activity as useful tool for potent therapeutic applications. However, functional studies should be conducted to confirm their therapeutic relevance.

Electronic supplementary material

The online version of this article (10.1186/s12860-018-0157-0) contains supplementary material, which is available to authorized users.