The potential use of mesenchymal stem cells in hematopoietic stem cell transplantation. Exp Mol Med. 2013;45:e2. [PMID: 23306700 PMCID: PMC3584660 DOI: 10.1038/emm.2013.2]

Mesenchymal stem cells preconditioned with a TLR5 agonist enhanced immunoregulatory effect through M2 macrophage polarization in a murine graft-versus-host disease model

Graft-versus-host disease (GVHD) is a common complication following hematopoietic stem cell transplantation and can be life-threatening. Mesenchymal stem cells (MSCs), adult stem cells with immunomodulatory properties, have been used as therapeutic agents in a variety of ways and have demonstrated efficacy against acute GVHD (aGVHD); however, variability in MSC pro- and anti-inflammatory properties and the limitation that they only exhibit immunosuppressive effects at high levels of inflammation have prevented their widespread clinical use. The outcomes of GVHD treated with MSCs in the clinic have been variable, and the underlying mechanisms remain unclear. Therefore, the unique biological effects of Toll-like receptor 5 (TLR5) agonists led us to compare and validate the efficacy of MSCs primed with KMRC011, a TLR5 agonist. KMRC011 is a stimulant that induces the secretion of cytokines, which play an important role in immune regulation. In this study, we found that MSCs pretreated with KMRC011 increased the secretion of immunosuppressive cytokines indoleamine 2,3-dioxygenase (IDO) and cyclooxygenase-2 (COX2) and increased the expression of M2 macrophage polarizing cytokines macrophage colony-stimulating factor (M-CSF) and interleukin 10 (IL-10) in vitro. We investigated the immunosuppressive effects of TLR5 agonist (KMRC011)-primed MSCs on lymphocytes and their preventive and therapeutic effects on an in vivo mouse aGVHD model. In vitro experiments showed that KMRC011-primed MSCs had enhanced immunosuppressive effects on lymphocyte proliferation. In vivo experiments showed that KMRC011-primed MSCs ameliorated GVHD severity in a mouse model of induced GVHD disease. Finally, macrophages harvested from the spleens of mice treated with KMRC011-primed MSCs showed a significant increase in the anti-inflammatory M2 phenotype. Overall, the results suggest that KMRC011-primed MSCs attenuated GVHD severity in mice by polarizing macrophages to the M2 phenotype and increasing the proportion of anti-inflammatory cells, opening new horizons for GVHD treatment.

Mesenchymal stem cells and cancer-associated fibroblasts as a therapeutic strategy for breast cancer

Breast cancer is the most common type of cancer and the leading cause of death among women. Recent evidence suggests that mesenchymal stromal/stem cells and cancer-associated fibroblasts (CAFs) have an essential role in cancer progression, invasion and therapy resistance. Therefore, they are considered as highly promising future therapeutic targets against breast cancer. The intrinsic tumour tropism and immunomodulatory capacities of mesenchymal stromal/stem cells are of special relevance for developing mesenchymal stromal/stem cells-based anti-tumour therapies that suppress primary tumour growth and metastasis. In addition, the utilization of therapies that target the stromal components of the tumour microenvironment in combination with standard drugs is an innovative tool that could improve patients' response to therapies and their survival. In this review, we discuss the currently available information regarding the possible use of mesenchymal stromal/stem cells-derived anti-tumour therapies, as well as the utilization of therapies that target CAFs in breast cancer microenvironment. Finally, these data can serve as a guide map for future research in this field, ultimately aiding the effective transition of these results into the clinic. LINKED ARTICLES: This article is part of a themed issue on Cancer Microenvironment and Pharmacological Interventions. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.2/issuetoc.

A comprehensive analysis of cell-autonomous and non-cell-autonomous regulation of myeloid leukemic cells: The prospect of developing novel niche-targeting therapies

Leukemic cells (LCs) arise from the hematopoietic stem/and progenitor cells (HSCs/HSPCs) and utilize cues from the bone marrow microenvironment (BMM) for their regulation in the same way as their normal HSC counterparts. Mesenchymal stromal cells (MSCs), a vital component of the BMM promote leukemogenesis by creating a protective and immune-tolerant microenvironment that can support the survival of LCs, helping them escape chemotherapy, thereby resulting in the relapse of leukemia. Conversely, MSCs also induce apoptosis in the LCs and inhibit their proliferation by interfering with their self-renewal potential. This review discusses the work done so far on cell-autonomous (intrinsic) and MSCs-mediated non-cell-autonomous (extrinsic) regulation of myeloid leukemia with a special focus on the need to investigate the extrinsic regulation of myeloid leukemia to understand the contrasting role of MSCs in leukemogenesis. These mechanisms could be exploited to formulate novel therapeutic strategies that specifically target the leukemic microenvironment.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: An Emerging Diagnostic and Therapeutic Biomolecules for Neurodegenerative Disabilities

Mesenchymal stem cells (MSCs) are a type of versatile adult stem cells present in various organs. These cells give rise to extracellular vesicles (EVs) containing a diverse array of biologically active elements, making them a promising approach for therapeutics and diagnostics. This article examines the potential therapeutic applications of MSC-derived EVs in addressing neurodegenerative disorders such as Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). Furthermore, the present state-of-the-art for MSC-EV-based therapy in AD, HD, PD, ALS, and MS is discussed. Significant progress has been made in understanding the etiology and potential treatments for a range of neurodegenerative diseases (NDs) over the last few decades. The contents of EVs are carried across cells for intercellular contact, which often results in the control of the recipient cell's homeostasis. Since EVs represent the therapeutically beneficial cargo of parent cells and are devoid of many ethical problems connected with cell-based treatments, they offer a viable cell-free therapy alternative for tissue regeneration and repair. Developing innovative EV-dependent medicines has proven difficult due to the lack of standardized procedures in EV extraction processes as well as their pharmacological characteristics and mechanisms of action. However, recent biotechnology and engineering research has greatly enhanced the content and applicability of MSC-EVs.

Systematic review and meta-analysis of mesenchymal stromal/stem cells as strategical means for the treatment of COVID-19

BACKGROUND

In coronavirus disease 2019 (COVID-19) patients, elevated levels of inflammatory cytokines from over stimulation of immune cells have become a concern due to the potential outburst of cytokine storm that damages the tissues and organs, especially the lungs. This leads to the manifestation of COVID-19 symptoms, such as pneumonia, acute respiratory distress syndrome (ARDS), multiple organ failure, and eventually death. Mesenchymal stromal/stem cells (MSCs) are currently one of hopeful approaches in treating COVID-19 considering its anti-inflammatory and immunomodulatory functions. On that account, the number of clinical trials concerning the use of MSCs for COVID-19 has been increasing. However, the number of systematic reviews and meta-analysis that specifically discuss its potential as treatment for the disease is still lacking. Therefore, this review will assess the safety and efficacy of MSC administration in COVID-19 patients.

OBJECTIVES

To pool evidence on the safety and efficacy of MSCs in treating COVID-19 by observing MSC-related adverse effects as well as evaluating its effects in reducing inflammatory response and improving pulmonary function.

DATA SOURCES AND METHODS

Following literature search across six databases and one trial register, full-text retrieval, and screening against eligibility criteria, only eight studies were included for data extraction. All eight studies evaluated the use of umbilical cord-derived mesenchymal stromal/stem cell (UC-MSC), infused intravenously. Of these eight studies, six studies were included in meta-analysis on the incidence of mortality, adverse events (AEs), and serious adverse events (SAEs), and the levels of C-reactive protein (CRP) and interleukin (IL)-6. Meta-analysis on pulmonary function was not performed due to insufficient data.

RESULTS

MSC-treated group showed significantly lower risk of mortality than the control group (p = 0.03). No statistical significance was observed on the incidence of AEs (p = 0.78) and SAEs (p = 0.44), and the levels of CRP (p = 0.06) and IL-6 (p = 0.09).

CONCLUSION

MSCs were safe for use, with lower risk of mortality and no association with AEs. Regarding efficacy, descriptive analysis showed indications of improvement on the inflammatory reaction, lung clearance, and oxygenation status despite the lack of statistical significance in meta-analysis of CRP and IL-6. Nevertheless, more studies are needed for affirmation.

REGISTRATION

This systematic review and meta-analysis was registered on the PROSPERO database (no. CRD42022307730).

Mesenchymal stroma/stem cells: Haematologists' friend or foe?

Mesenchymal stromal cells (MSCs) are non-haematopoietic cells found in fetal and adult organs, that play important roles in tissue repair, inflammation and immune modulation. MSCs residing in the bone marrow interact closely with haematopoietic cells and comprise an important component of the microenvironment supporting haematopoiesis, in both health and disease states. Since their identification in 1970, basic scientific and preclinical research efforts have shed light on the role of MSCs in the regulation of haematopoiesis and evoked interest in their clinical application in haematopoietic stem cell transplantation (HSCT) and malignant haematology. Over the last two decades, these research efforts have led to numerous clinical trials, which have established the safety of MSC therapy; however, the optimal mode of administration and the benefit remain inconclusive. In this paper, we will review the clinical experience with use of MSCs in HSCT for enhancement of engraftment, prevention and treatment of graft-versus-host disease and haemorrhagic cystitis. Then, we will discuss the contradictory evidence regarding tumour-promoting versus tumour-suppressing effects of MSCs in haematological malignancies, which may have relevance for future clinical applications.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles as Biological Carriers for Drug Delivery in Cancer Therapy

Cancer is the second leading cause of death worldwide, with 10.0 million cancer deaths in 2020. Despite advances in targeted therapies, some pharmacological drawbacks associated with anticancer chemo and immunotherapeutic agents include high toxicities, low bioavailability, and drug resistance. In recent years, extracellular vesicles emerged as a new promising platform for drug delivery, with the advantage of their inherent biocompatibility and specific targeting compared to artificial nanocarriers, such as liposomes. Particularly, mesenchymal stem/stromal cells were proposed as a source of extracellular vesicles for cancer therapy because of their intrinsic properties: high in vitro self-renewal and proliferation, regenerative and immunomodulatory capacities, and secretion of extracellular vesicles that mediate most of their paracrine functions. Moreover, extracellular vesicles are static and safer in comparison with mesenchymal stem/stromal cells, which can undergo genetic/epigenetic or phenotypic changes after their administration to patients. In this review, we summarize currently reported information regarding mesenchymal stem/stromal cell-derived extracellular vesicles, their proper isolation and purification techniques - from either naive or engineered mesenchymal stem/stromal cells - for their application in cancer therapy, as well as available downstream modification methods to improve their therapeutic properties. Additionally, we discuss the challenges associated with extracellular vesicles for cancer therapy, and we review some preclinical and clinical data available in the literature.

Defects in Long-Term APC Repopulation Ability of Adult Human Bone Marrow Hematopoietic Stem Cells (HSCs) Compared with Fetal Liver HSCs

Immunodeficient mice reconstituted with immune systems from patients, or personalized immune (PI) mice, are powerful tools for understanding human disease. Compared with immunodeficient mice transplanted with human fetal thymus tissue and fetal liver-derived CD34⁺ cells administered i.v. (Hu/Hu mice), PI mice, which are transplanted with human fetal thymus and adult bone marrow (aBM) CD34⁺ cells, demonstrate reduced levels of human reconstitution. We characterized APC and APC progenitor repopulation in human immune system mice and detected significant reductions in blood, bone marrow (BM), and splenic APC populations in PI compared with Hu/Hu mice. APC progenitors and hematopoietic stem cells (HSCs) were less abundant in aBM CD34⁺ cells compared with fetal liver-derived CD34⁺ cell preparations, and this reduction in APC progenitors was reflected in the BM of PI compared with Hu/Hu mice 14-20 wk posttransplant. The number of HSCs increased in PI mice compared with the originally infused BM cells and maintained functional repopulation potential, because BM from some PI mice 28 wk posttransplant generated human myeloid and lymphoid cells in secondary recipients. Moreover, long-term PI mouse BM contained functional T cell progenitors, evidenced by thymopoiesis in thymic organ cultures. Injection of aBM cells directly into the BM cavity, transgenic expression of hematopoietic cytokines, and coinfusion of human BM-derived mesenchymal stem cells synergized to enhance long-term B cell and monocyte levels in PI mice. These improvements allow a sustained time frame of 18-22 wk where APCs and T cells are present and greater flexibility for modeling immune disease pathogenesis and immunotherapies in PI mice.

Differences and similarities between mesenchymal stem cell and endothelial progenitor cell immunoregulatory properties against T cells

Bone-marrow-derived mesenchymal stem cells and endothelial progenitor cells have some interesting biological properties that make them unique for cell therapy of degenerative and cardiovascular disorders. Although both cell populations have been already studied and used for their regenerative potentials, recently their special immunoregulatory features have brought much more attention. Mesenchymal stem cells and endothelial progenitor cells have both proangiogenic functions and have been shown to suppress the immune response, particularly T cell proliferation, activation, and cytokine production. This makes them suitable choices for allogeneic stem cell transplantation. Nevertheless, these two cells do not have equal immunoregulatory activities. Many elements including their extraction sources, age/passage, expression of different markers, secretion of bioactive mediators, and some others could change the efficiency of their immunosuppressive function. However, to our knowledge, no publication has yet compared mesenchymal stem cells and endothelial progenitor cells for their immunological interaction with T cells. This review aims to specifically compare the immunoregulatory effect of these two populations including their T cell suppression, deactivation, cytokine production, and regulatory T cells induction capacities. Moreover, it evaluates the implications of the tumor necrosis factor alpha-tumor necrosis factor receptor 2 axis as an emerging immune checkpoint signaling pathway controlling most of their immunological properties.

A COVID-19 Overview and Potential Applications of Cell Therapy

The COVID-19 pandemic has already reaped thousands of lives, although many scientific studies already showed the possibility of this scenario. Currently, further attention is provided to patients depicting comorbidities such as respiratory or immunocompromised diseases, hypertension, and diabetes, as these individuals show a worse prognosis. Cell therapies using stem cells and/or defense cells, combined or not with traditional treatment, could be an outstanding strategy for COVID-19 management since these treatments can act by modulating the immune system, reducing proliferation, and favoring the complete elimination of the virus. In this review, we highlight the main molecular characteristics of this novel coronavirus, as well as the main pathognomonic signs of COVID-19. Furthermore, possible cell therapies are pointed out to show alternative treatments against COVID-19 and its sequels.

Pretreatment with licochalcone a enhances therapeutic activity of rat bone marrow mesenchymal stem cells in animal models of colitis

OBJECTIVES

Colitis has a high prevalence rate, limited treatment options, and needs to be solved urgently. Application of Licochacone A (LA) or rBMMSCs alone in the treatment of colitis has a certain but limited effect. This study aims to develop an LA-based strategy to improve mesenchymal stem cells' (MSCs') therapeutic capacity in mice DSS-induced colitis by increasing the number of MSCs migrating to the inflammation site.

MATERIALS AND METHODS

In vivo, we injected MSCs pretreated with LA, MSCs alone, or PBS into the tail vein of colitis mice, and assessed the colon length, disease activity index (DAI) score, body weight, HAI score, and tracked the location of MSCs at day 10. In vitro, we knocked down the CXCR4 gene by siRNA and then treated it with LA, then tested the mRNA level of CXCR4 and the migration ability of group CXCR4, CXCR4+LA, LA, and control to verify the relationship between this effect and the SDF-1-CXCR4 signaling pathway.

RESULTS

The mice that received LA- pretreated MSCs had ameliorated body weight loss, preserved colon morphology, and decreased DAI and histological activity index (HAI) compared with the MSCs group. Besides, the number of MSCs migrating to the inflammation site significantly increased in group LA+MSCs, and expression of CXCR4 significantly increased too. Furthermore, we found that LA could partly revise the decrease of the migration of MSCs and the expression of CXCR4 mRNA caused by CXCR4-siRNA.

CONCLUSION

LA may improve the migration ability of MSCs through increasing CXCR4 expression therapy enhancing their therapeutic activity.

Bone marrow/bone pre-metastatic niche for breast cancer cells colonization: The role of mesenchymal stromal cells

Breast cancer is one of the most common oncological pathologies in women worldwide. While its early diagnosis has considerably improved, about 70 % of advanced patients develop bone metastases with a high mortality rate. Several authors demonstrated that primary breast cancer cells prepare their future metastatic niche -known as the pre-metastatic niche- to turn it into an "optimal soil" for colonization. The role of the different cellular components of the bone marrow/bone niche in bone metastasis has been well described. However, studying the changes that occur in this microenvironment before tumor cells arrival has become a novel research field. Therefore, the purpose of this review is to describe the current knowledge about the modulation of the normal bone marrow/bone niche by the primary breast tumor, in particular, highlighting the role of mesenchymal stem/stromal cells in transforming this soil into a pre-metastatic niche for breast cancer cells colonization.

Tonsil-derived mesenchymal stem cells enhance allogeneic bone marrow engraftment via collagen IV degradation

BACKGROUND

Co-transplantation of bone marrow cells (BMCs) and mesenchymal stem cells (MSCs) is used as a strategy to improve the outcomes of bone marrow transplantation. Tonsil-derived MSCs (TMSCs) are a promising source of MSCs for co-transplantation. Previous studies have shown that TMSCs or conditioned media from TMSCs (TMSC-CM) enhance BMC engraftment. However, the factors in TMSCs that promote better engraftment have not yet been identified.

METHODS

Mice were subjected to a myeloablative regimen of busulfan and cyclophosphamide, and the mRNA expression in the bone marrow was analyzed using an extracellular matrix (ECM) and adhesion molecule-targeted polymerase chain reaction (PCR) array. Nano-liquid chromatography with tandem mass spectrometry, real-time quantitative PCR, western blots, and enzyme-linked immunosorbent assays were used to compare the expression levels of metalloproteinase 3 (MMP3) in MSCs derived from various tissues, including the tonsils, bone marrow, adipose tissue, and umbilical cord. Recipient mice were conditioned with busulfan and cyclophosphamide, and BMCs, either as a sole population or with control or MMP3-knockdown TMSCs, were co-transplanted into these mice. The effects of TMSC-expressed MMP3 were investigated. Additionally, Enzchek collagenase and Transwell migration assays were used to confirm that the collagenase activity of TMSC-expressed MMP3 enhanced BMC migration.

RESULTS

Mice subjected to the myeloablative regimen exhibited increased mRNA expression of collagen type IV alpha 1/2 (Col4a1 and Col4a2). Among the various extracellular matrix-modulating proteins secreted by TMSCs, MMP3 was expressed at higher levels in TMSCs than in other MSCs. Mice co-transplanted with BMCs and control TMSCs exhibited a higher survival rate, weight recovery, and bone marrow cellularity compared with mice co-transplanted with BMCs and MMP3-knockdown TMSCs. Control TMSC-CM possessed higher collagenase activity against collagen IV than MMP3-knockdown TMSC-CM. TMSC-CM also accelerated BMC migration by degrading collagen IV in vitro.

CONCLUSIONS

Collectively, these results indicate that TMSCs enhance BMC engraftment by the secretion of MMP3 for the modulation of the bone marrow extracellular matrix.

The Role of Marrow Microenvironment in the Growth and Development of Malignant Plasma Cells in Multiple Myeloma

The development and effectiveness of novel therapies in multiple myeloma have been established in large clinical trials. However, multiple myeloma remains an incurable malignancy despite significant therapeutic advances. Accumulating data have elucidated our understanding of the genetic background of the malignant plasma cells along with the role of the bone marrow microenvironment. Currently, the interaction among myeloma cells and the components of the microenvironment are considered crucial in multiple myeloma pathogenesis. Adhesion molecules, cytokines and the extracellular matrix play a critical role in the interplay among genetically transformed clonal plasma cells and stromal cells, leading to the proliferation, progression and survival of myeloma cells. In this review, we provide an overview of the multifaceted role of the bone marrow microenvironment in the growth and development of malignant plasma cells in multiple myeloma.

Efficacy and safety of mesenchymal stem cells co-infusion in allogeneic hematopoietic stem cell transplantation: a systematic review and meta-analysis

Background

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is life-saving for severe hematological conditions. However, its outcomes need further improvement, and co-infusion of mesenchymal stem cells (MSCs) may show promise. A growing body of research on this subject exists, while the results of different trials are conflicting. A systematic review and meta-analysis is needed to appraise the real efficacy and safety of MSC co-transplantation in allo-HSCT.

Methods

Studies comparing MSC co-transplantation in allo-HSCT with allo-HSCT alone were searched in six medical databases from inception to June 10, 2020. The primary outcomes were engraftment and graft-versus-host disease (aGVHD and cGVHD, respectively). Other outcomes included overall survival (OS), relapse rate (RR), non-relapse mortality (NRM), and immune reconstitution. Information was independently extracted by two investigators. Methodological quality was assessed using the Cochrane Collaboration tool. Meta-analysis was performed using RevMan 5.4.

Results

Six randomized controlled trials (RCTs) and 13 non-randomized controlled trials (nRCTs) were included. MSC co-infusion resulted in shorter times to neutrophil engraftment (RCTs: standardized mean difference (SMD) − 1.20, p = 0.04; nRCTs: SMD − 0.54, p = 0.04) and platelet engraftment (RCTs: SMD − 0.60, p = 0.04; nRCTs: SMD − 0.70, p = 0.01), a lower risk of cGVHD (RCTs: risk ratio (RR) 0.53, p = 0.01; nRCTs: RR 0.50, p <  0.01), and a slightly positive trend towards reducing the risk of aGVHD and NRM, without affecting RR and OS. Subgroup analyses revealed that when MSCs were co-transplanted, children and adolescents, and patients receiving human leukocyte antigen (HLA)-nonidentical HSCT showed improvements in engraftment and incidence of GVHD and NRM; adults and patients who received HLA-identical HSCT had lower cGVHD; patients with malignancies exhibited improvements in GVHD and NRM incidence; and patients with non-malignancies experienced accelerated engraftment. Notably, a reduced OS was observed in patients with hematological malignancies undergoing HLA-identical HSCT.

Conclusion

MSC co-infusion generally improved engraftment and reduced cGVHD, without increasing mortality or relapse. Regarding aGVHD and NRM, the effects of MSCs were not quite significant. Specifically, our data support the utilization of MSC co-transplantation in children and young individuals with HLA-nonidentical HSCT, but not in adult patients with hematological malignancies undergoing HLA-identical HSCT.

Mesenchymal stromal cells as prophylaxis for graft-versus-host disease in haplo-identical hematopoietic stem cell transplantation recipients with severe aplastic anemia?-a systematic review and meta-analysis

BACKGROUND

Mesenchymal stromal cells (MSCs) are an emerging prophylaxis option for graft-versus-host disease (GVHD) in haplo-identical hematopoietic stem cell transplantation (haplo-HSCT) recipients with severe aplastic anemia (SAA), but studies have reported inconsistent results. This systematic review and meta-analysis evaluates the efficacy of MSCs as prophylaxis for GVHD in SAA patients with haplo-HSCT.

METHODS

Studies were retrieved from PubMed, EMBASE, Cochrane, Web of Science, and http://clinicaltrials.gov from establishment to February 2020. Twenty-nine single-arm studies (n = 1456) were included, in which eight (n = 241) studies combined with MSCs and eleven (n = 1215) reports without MSCs in haplo-HSCT for SAA patients. The primary outcomes were the incidences of GVHD. Other outcomes included 2-year overall survival (OS) and the incidence of cytomegalovirus (CMV) infection. Odds ratios (ORs) were calculated to compare the results pooled through random or fixed effects models.

RESULTS

Between MSCs and no MSCs groups, no significant differences were found in the pooled incidences of acute GVHD (56.0%, 95% CI 48.6-63.5% vs. 47.2%, 95% CI 29.0-65.4%; OR 1.43, 95% CI 0.91-2.25; p = 0.123), grade II-IV acute GVHD (29.8%, 95% CI 24.1-35.5% vs. 30.6%, 95% CI 26.6-34.6%; OR 0.97, 95% CI 0.70-1.32; p = 0.889), and chronic GVHD (25.4%, 95% CI 19.8-31.0% vs. 30.0%, 95% CI 23.3-36.6%; OR 0.79, 95% CI 0.56-1.11; p = 0.187). Furtherly, there was no obvious difference in 2-year OS (OR 0.98, 95% CI 0.60-1.61; p = 1.000) and incidence of CMV infection (OR 0.61, 95% CI 0.40-1.92; p = 0.018).

CONCLUSIONS

Our meta-analysis indicates that the prophylactic use of MSC co-transplantation is not an effective option for SAA patients undergoing haplo-HSCT. Hence, the general co-transplantation of MSCs for SAA haplo-HSCT recipients may lack evidence-based practice.

Umbilical cord blood-derived mesenchymal stromal cells promote myeloid-derived suppressor cell proliferation by secreting HLA-G to reduce acute graft-versus-host disease after hematopoietic stem cell transplantation

BACKGROUND AIMS

Mesenchymal stem cells (MSCs) use multiple mechanisms to constrain both innate and adaptive immune responses to prevent graft-versus-host disease (GVHD). Myeloid-derived suppressor cells (MDSCs), as a heterogeneous population of early myeloid progenitor cells originating from bone marrow, are a naturally occurring immune regulatory population associated with inhibition of ongoing inflammatory responses, indicating their potential for GVHD therapy. There is accumulating evidence that MSCs and MDSCs do not act independently, but rather establish crosstalk. However, the role of MSCs in MDSC expansion and activation in GVHD remains unexplored.

METHODS

In vitro experiments included 2 groups: peripheral blood mononuclear cells (PBMCs) after mobilization and human umbilical cord blood-derived MSCs (UCB-MSCs) co-cultured with PBMCs. The number and functional difference of MDSCs in PBMCs were determined by flow cytometry. The culture supernatants of co-cultured cells were analyzed to identify cytokines involved in MDSC proliferation. The relationship between MSCs and MDSCs was clarified in GVHD and graft-versus-leukemia (GVL) animal models.

RESULTS

In vitro experiments confirmed that UCB-MSCs secreted HLA-G protein to promote and maintain the proliferation of MDSCs in peripheral blood after granulocyte colony-stimulating factor mobilization, and UCB-MSCs mediated the function of MDSCs to inhibit the proliferation of T cells and promote the proliferation of regulatory T cells. UCB-MSCs overexpressing HLA-G induced MDSC production in recipient mice, improved the ability of MDSCs to suppress T cells and further reduced acute GVHD (aGVHD) symptoms and survival time without influencing GVL effects.

CONCLUSIONS

UCB-MSCs expanded MDSCs via HLA-G/Ig-like transcript 4, reducing the severity of aGVHD without affecting GVL. The immunosuppressive potential of MSCs for the treatment of aGVHD significantly affects the development of MDSCs, thereby consolidating the position of MSCs in the prevention and treatment of aGVHD.

Mesenchymal Stem Cells: A New Generation of Therapeutic Agents as Vehicles in Gene Therapy

In recent years, mesenchymal stem cells (MSCs) as a new tool for therapeutic gene delivery in clinics have attracted much attention. Their advantages cover longer lifespan, better isolation, and higher transfection efficiency and proliferation rate. MSCs are the preferred approach for cell-based therapies because of their in vitro self-renewal capacity, migrating especially to tumor tissues, as well as anti-inflammatory and immunomodulatory properties. Therefore, they have considerable efficiency in genetic engineering for future clinical applications in cancer gene therapy and other diseases. For improving therapeutic efficiency, targeted therapy of cancers can be achieved through the sustained release of therapeutic agents and functional gene expression induction to the intended tissues. The development of a new vector in gene therapy can improve the durability of a transgene expression. Also, the safety of the vector, if administered systemically, may resolve several problems, such as durability of expression and the host immune response. Currently, MSCs are prominent candidates as cell vehicles for both preclinical and clinical trials due to the secretion of therapeutic agents in several cancers. In the present study, we discuss the status of gene therapy in both viral and non-viral vectors along with their limitations. Throughout this study, the use of several nano-carriers for gene therapy is also investigated. Finally, we critically discuss the promising advantages of MSCs in targeted gene delivery, tumor inhibition and their utilization as the gene carriers in clinical situations.

Efficacy of mesenchymal stem cells in the treatment of gastrointestinal malignancies

Mesenchymal stem cells (MSCs), which are a kind of stem cell, possess an immune privileged nature, tumour homing features, and multi-lineage differentiation ability. MSCs have been studied in many fields, such as tissue engineering, nervous system diseases, and cancer treatment. In recent years, an increasing number of researchers have focused on the effects of MSCs on various kinds of tumours. However, the concrete anticancer efficacy of MSCs is still controversial. Gastrointestinal (GI) malignancies are the major causes of cancer-related death worldwide. The interactions of MSCs and GI cancer cells in specific conditions have attracted increasing attention. In this review, we introduce the characteristics of MSCs and analyse the effects of MSCs on GI malignancies, including gastric cancer, hepatoma, pancreatic cancer, and colorectal cancer. In addition, we also provide our perspectives on why MSCs may play different roles in GI malignancies and further research directions to increase the treatment efficacy of MSCs on GI malignancies.

Bone Marrow-Derived Mesenchymal Stromal Cells: A Novel Target to Optimize Hematopoietic Stem Cell Transplantation Protocols in Hematological Malignancies and Rare Genetic Disorders

: Mesenchymal stromal cells (MSCs) are crucial elements in the bone marrow (BM) niche where they provide physical support and secrete soluble factors to control and maintain hematopoietic stem progenitor cells (HSPCs). Given their role in the BM niche and HSPC support, MSCs have been employed in the clinical setting to expand ex-vivo HSPCs, as well as to facilitate HSPC engraftment in vivo. Specific alterations in the mesenchymal compartment have been described in hematological malignancies, as well as in rare genetic disorders, diseases that are amenable to allogeneic hematopoietic stem cell transplantation (HSCT), and ex-vivo HSPC-gene therapy (HSC-GT). Dissecting the in vivo function of human MSCs and studying their biological and functional properties in these diseases is a critical requirement to optimize transplantation outcomes. In this review, the role of MSCs in the orchestration of the BM niche will be revised, and alterations in the mesenchymal compartment in specific disorders will be discussed, focusing on the need to correct and restore a proper microenvironment to ameliorate transplantation procedures, and more in general disease outcomes.

Mesenchymal stem cells as carrier of the therapeutic agent in the gene therapy of blood disorders

Nonhematopoietic stem cells as a delivery platform of therapeutic useful genes have attracted widespread attention in recent years, owing to gained a long lifespan, easy separation, high proliferation, and high transfection capacity. Mesenchymal stem/stromal cells (MSCs) are the choice of the cells for gene and cell therapy due to high self-renewal capacity, high migration rate to the site of the tumor, and with immune suppressive and anti-inflammatory properties. Hence, it has a high potential of safety genetic modification of MSCs for antitumor gene expression and has paved the way for the clinical application of these cells to target the therapy of cancers and other diseases. The aim of gene therapy is targeted treatment of cancers and diseases through recovery, change, or enhancement cell performance to the sustained secretion of useful therapeutic proteins and induction expression of the functional gene in intended tissue. Recent developments in the vectors designing leading to the increase and durability of expression and improvement of the safety of the vectors that overcome a lot of problems, such as durability of expression and the host immune response. Nowadays, gene therapy approach is used by MSCs as a delivery vehicle in the preclinical and the clinical trials for the secretion of erythropoietin, recombinant antibodies, coagulation factors, cytokines, as well as angiogenic inhibitors in many blood disorders like anemia, hemophilia, and malignancies. In this study, we critically discuss the status of gene therapy by MSCs as a delivery vehicle for the treatment of blood disorders. Finally, the results of clinical trial studies are assessed, highlighting promising advantages of this emerging technology in the clinical setting.

Application of "Primed" Mesenchymal Stromal Cells in Hematopoietic Stem Cell Transplantation: Current Status and Future Prospects

Regenerative potential of mesenchymal stem/stromal cells (MSCs) has led to their application in various cellular therapies. Since in vivo these cells are present in very low numbers, they need expansion in culture to get clinically relevant numbers; however, such long-term ex vivo manipulation leads to loss of their regenerative capacity. Although use of naïve MSCs is still the most common approach used in various therapies, several strategies, both genetic and pharmacological, are being tried out to boost the regenerative capacity of in vitro expanded MSCs. Such manipulations are very commonly reported for regeneration of various tissues like bone, cartilage, kidney, pancreas, and others. Likewise, several efforts have been made to investigate priming of MSCs to enhance their immunoregulatory activity, but such efforts have not been made to the same extent for enhancing the efficacy of hematopoietic stem cell transplantation (HSCT). Development of such approaches for HSCT would not only be useful for enhancing the transplantation efficacy of cord blood cells, which are fewer in numbers, and aged HSCs, which could be functionally compromised, but also for genetically modified HSCs, which are likely to be both, fewer in number and functionally compromised. This review specifically deals with application of "primed" MSCs in the scenario of HSCT.

Nanofibrillar cellulose wound dressing supports the growth and characteristics of human mesenchymal stem/stromal cells without cell adhesion coatings

BACKGROUND

In the field of regenerative medicine, delivery of human adipose-derived mesenchymal stem/stromal cells (hASCs) has shown great promise to promote wound healing. However, a hostile environment of the injured tissue has shown considerably to limit the survival rate of the transplanted cells, and thus, to improve the cell survival and retention towards successful cell transplantation, an optimal cell scaffold is required. The objective of this study was to evaluate the potential use of wood-derived nanofibrillar cellulose (NFC) wound dressing as a cell scaffold material for hASCs in order to develop a cell transplantation method free from animal-derived components for wound treatment.

METHODS

Patient-derived hASCs were cultured on NFC wound dressing without cell adhesion coatings. Cell characteristics, including cell viability, morphology, cytoskeletal structure, proliferation potency, and mesenchymal cell and differentiation marker expression, were analyzed using cell viability assays, electron microscopy, immunocytochemistry, and quantitative or reverse transcriptase PCR. Student's t test and one-way ANOVA followed by a Tukey honestly significant difference post hoc test were used to determine statistical significance.

RESULTS

hASCs were able to adhere to NFC dressing and maintained high cell survival without cell adhesion coatings with a cell density-dependent manner for the studied period of 2 weeks. In addition, NFC dressing did not induce any remarkable cytotoxicity towards hASCs or alter the morphology, proliferation potency, filamentous actin structure, the expression of mesenchymal vimentin and extracellular matrix (ECM) proteins collagen I and fibronectin, or the undifferentiated state of hASCs.

CONCLUSIONS

As a result, NFC wound dressing offers a functional cell culture platform for hASCs to be used further for in vivo wound healing studies in the future.

Programmable microencapsulation for enhanced mesenchymal stem cell persistence and immunomodulation

Mesenchymal stem cell (MSC) therapies demonstrate particular promise in ameliorating diseases of immune dysregulation but are hampered by short in vivo cell persistence and inconsistencies in phenotype. Here, we demonstrate that biomaterial encapsulation into alginate using a microfluidic device could substantially increase in vivo MSC persistence after intravenous (i.v.) injection. A combination of cell cluster formation and subsequent cross-linking with polylysine led to an increase in injected MSC half-life by more than an order of magnitude. These modifications extended persistence even in the presence of innate and adaptive immunity-mediated clearance. Licensing of encapsulated MSCs with inflammatory cytokine pretransplantation increased expression of immunomodulatory-associated genes, and licensed encapsulates promoted repopulation of recipient blood and bone marrow with allogeneic donor cells after sublethal irradiation by a ∼2-fold increase. The ability of microgel encapsulation to sustain MSC survival and increase overall immunomodulatory capacity may be applicable for improving MSC therapies in general.

The role of mesenchymal stem cells in hematopoietic stem cell transplantation: prevention and treatment of graft-versus-host disease

Background

The use and effectiveness of hematopoietic stem cell transplantation (HSCT) are limited by lethal complications, i.e., acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively), in which immune cells from the donor attack healthy recipient tissues. GVHD presents both prophylactic and therapeutic challenges, and overall survival is poor. Mesenchymal stem cells (MSCs) show considerable promise in the treatment of GVHD because of their potential immunomodulatory activity. Multiple studies have been performed to explore the possible benefit of MSCs in GVHD, but the results of these studies are sometimes conflicting. Therefore, we performed a systematic review and meta-analysis to estimate the effect of MSC infusion on GVHD treatment and prevention.

Methods

We systematically searched the MEDLINE (PubMed), Cochrane Library, EMBASE, ClinicalTrials.gov, and SinoMed CBM databases to identify studies published before February 2018 involving patients with hematologic malignancies undergoing HSCT and receiving MSC-based or conventional therapy. We included studies if they reported on the outcomes of interest.

Results

Ultimately, 10 studies were selected from among 413 candidates. According to our meta-analyses, compared with conventional treatment, MSC therapy demonstrated substantial improvements in terms of complete response (CR) and overall survival for cGVHD. However, MSC therapy did not show substantial improvements in terms of engraftment, the incidence of aGVHD, relapse, death, death due to relapse, or death due to infection. Subgroup analyses showed that MSCs derived from the umbilical cord (U-MSCs) and MSC infusion after HSCT substantially improved engraftment and cGVHD incidence, whereas MSCs derived from bone marrow (B-MSCs) and MSC infusion before HSCT shows no improvement. In addition, B-MSCs and MSC infusion before HSCT tend to prolong engraftment time, as well as increase the rates of relapse and death.

Conclusions

MSC infusion can reduce cGVHD but not aGVHD incidence and showed a positive effect in patients who already had aGVHD. For GVHD prevention, the use of U-MSCs and MSC infusion after HSCT were optimal for reducing cGVHD incidence and promoting engraftment, and might help decrease the incidence rate of relapse and death. However, B-MSCs and MSC infusion before HSCT may be harmful to patients and thus require serious consideration. A lack of robust evidence, owing to the small number of studies and small sample sizes, indicates a need for further high-quality clinical trials including large numbers of patients to validate our findings.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1287-9) contains supplementary material, which is available to authorized users.

Emerging Role of Mesenchymal Stromal Cell-Derived Extracellular Vesicles in Pathogenesis of Haematological Malignancies

Homoeostasis of bone marrow microenvironment depends on a precise balance between cell proliferation and death, which is supported by the cellular-extracellular matrix crosstalk. Multipotent mesenchymal stromal cells (MSC) are the key elements to provide the specialized bone marrow microenvironment by supporting, maintaining, and regulating the functions and fate of haematopoietic stem cells. Despite the great potential of MSC for cell therapy in several diseases due to their regenerative, immunomodulatory, and anti-inflammatory properties, they can also contribute to modulate tumor microenvironment. The extracellular vesicles that comprise exosomes and microvesicles are important mediators of intercellular communication due to their ability to change phenotype and physiology of different cell types. These vesicles may interact not only with neighbouring cells but also with cells from distant tissues to either maintain tissue homoeostasis or participate in disease pathogenesis. This review focuses on the current knowledge about the physiological role of MSC-extracellular vesicles, as well as their deregulation in haematological malignancies and their potential applications as biomarkers for diagnosis, progression, and treatment monitoring of such diseases.

Wharton's Jelly Mesenchymal Stem Cell Administration Improves Quality of Life and Self-Sufficiency in Children with Cerebral Palsy: Results from a Retrospective Study

The aim of this paper was to describe the outcome of the therapeutic administration of allogenic mesenchymal stem cells obtained from Wharton's jelly (WJ-MSCs) in children with cerebral palsy (CP) during a medical therapeutic experiment. We retrospectively analyzed the records of 109 patients recruited in daily clinical practice. Each patient received 1–10 injections and was examined by the same neurologist (study investigator (SI)) on the day of each infusion. The SI used a 6-point Likert scale to assess the quality of life (QoL) and self-sufficiency of the patients on the basis of the neurological examination. Children with >50% follow-ups after this administration were included into the quantitative analysis. In addition, the assessments of the parents and other health care professionals were obtained for 23 patients and compared with those of the SI. Forty-eight of 54 analyzed patients (88.9%) achieved some improvement in health status. Forty-eight (88.9%) patients experienced an increase in their QoL, and 21 patients (38.9%) achieved an increase in their self-sufficiency level. Improvement was achieved in 17 areas. Adverse events were mild and temporary except one case of epilepsy deterioration leading to treatment discontinuation. Age, body mass, and cell dose were not significant predictors of QoL response, contrary to epilepsy; developmental breakthrough was dose-dependent.

Mesenchymal Stem Cells, Immune Cells and Tumor Cells Crosstalk: A Sinister Triangle in the Tumor Microenvironment

Mesenchymal Stem Cells [MSCs] are a heterogeneous population of fibroblast-like cells which maintain self-renewability and pluripotency. Many studies have demonstrated the immunomodulatory effects of MSCs on the innate and adaptive immune cells. As a result of interactions with tumor cells, microenvironment and immune-stimulating milieu, MSCs contribute to tumor progression by several mechanisms, including sustained proliferative signal in cancer stem cells [CSCs], inhibition of tumor cell apoptosis, transition to tumor-associated fibroblasts [TAFs], promotion of angiogenesis, stimulation of epithelial-mesenchymal transition [EMT], suppression of immune responses, and consequential promotion of tumor metastasis. Here, we present an overview of the latest findings on Janusfaced roles that MSCs play in the tumor microenvironment [TME], with a concise focus on innate and adaptive immune responses.

[Galectin-3 induces differentiation of rat bone marrow mesenchymal stem cells into hepatocyte-like cells]

OBJECTIVE

To investigate the effect of galectin-3 in inducing the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) into hepatocyte- like cells and explore the involvement of the signaling pathways in the induced cell differentiation.

METHODS

The third passage of cultured rat femoral BMSCs were treated with 0.5 μg/mL galectin-3, 20 ng/mL hepatocyte growth factor (HGF) or both to induce their differentiation, with untreated rat BMSCs and hepatocytes as controls. At 7, 14, 21 and 28 days of induction, the cells were examined for morphological changes followed by glycogen staining, quantitative real-time PCR and Western blotting. Gene microarray technique was used to examine the mRNA expression profile of the BMSCs induced with galectin-3. The BMSCs were also induced with galectin-3 in combination with XMU-MP-1, a Hippo signaling pathway inhibitor, after which Western blotting was performed to detect the expressions of YAP, P-YAP, ALB, AFP and CK-18 in the cells.

RESULTS

The cells isolated from the femoral bone marrow of SD rats showed a consistent surface marker phenotype with the BMSCs. Induction with galectin-3, HGF, or both all resulted in gradual morphological changes of the BMSCs into hepatocyte-like cells, and the cells with a combined induction for 28 days showed the highest morphological similarity with hepatocytes. The cells induced with galectin-3, HGF, or their combination for 28 days all showed increased positivity rate of glycogen staining, which was the highest in the cells with combined induction (P &lt; 0.05) without significant difference between the cells induced with galectin-3 and HGF alone (P &gt; 0.05). Induction with galectin-3 and HGF alone both increased the expressions of AFP, ALB and CK-18 mRNAs in the cells, and their expression levels were similar between the cells at 28 days (P &gt; 0.05). Galectin-3 and HGF did not show an interactive effect on the mRNA expressions of AFP (F=0.236, P=0.640) or ALB (F=50.639, P=0.000), but had a synergistic effect on CK-18 mRNA expression (F=50.639, P=0.000). The protein expressions of AFP, ALB and CK18 were also increased in the induced cells but not detected in the cells without induction. Gene microarray results revealed 27 up-regulated genes and 62 down-regulated genes in galectin-3-induced BMSCs involving TGF-β, PI3K-Akt and Hippo signal pathways. Induction with galectin-3 and galectin-3+XMU-MP-1 increased YAP expression in the cells, and galectin-3+XMU-MP-1 was more efficient to induce the differentiation of the BMSCs.

CONCLUSIONS

Galectin-3 can induce the differentiation of rat BMSCs into hepatocyte-like cells, and the combination with HGF increases the efficiency of induced differentiation of the cells. TGF-β, PI3K-Akt and Hippo pathways are involved in the induced differentiation of the BMSCs, and inhibiting Hippo pathway can improve the induction efficiency.

GMP-compatible and xeno-free cultivation of mesenchymal progenitors derived from human-induced pluripotent stem cells

Background

Human mesenchymal stem cells are a strong candidate for cell therapies owing to their regenerative potential, paracrine regulatory effects, and immunomodulatory activity. Yet, their scarcity, limited expansion potential, and age-associated functional decline restrict the ability to consistently manufacture large numbers of safe and therapeutically effective mesenchymal stem cells for routine clinical applications. To overcome these limitations and advance stem cell treatments using mesenchymal stem cells, researchers have recently derived mesenchymal progenitors from human-induced pluripotent stem cells. Human-induced pluripotent stem cell-derived progenitors resemble adult mesenchymal stem cells in morphology, global gene expression, surface antigen profile, and multi-differentiation potential, but unlike adult mesenchymal stem cells, it can be produced in large numbers for every patient. For therapeutic applications, however, human-induced pluripotent stem cell-derived progenitors must be produced without animal-derived components (xeno-free) and in accordance with Good Manufacturing Practice guidelines.

Methods

In the present study we investigate the effects of expanding mesodermal progenitor cells derived from two human-induced pluripotent stem cell lines in xeno-free medium supplemented with human platelet lysates and in a commercial high-performance Good Manufacturing Practice-compatible medium (Unison Medium).

Results

The results show that long-term culture in xeno-free and Good Manufacturing Practice-compatible media somewhat affects the morphology, expansion potential, gene expression, and cytokine profile of human-induced pluripotent stem cell-derived progenitors but supports cell viability and maintenance of a mesenchymal phenotype equally well as medium supplemented with fetal bovine serum.

Conclusions

The findings support the potential to manufacture large numbers of clinical-grade human-induced pluripotent stem cell-derived mesenchymal progenitors for applications in personalized regenerative medicine.

Graphical abstract

Electronic supplementary material

The online version of this article (10.1186/s13287-018-1119-3) contains supplementary material, which is available to authorized users.

The Potential of Menstrual Blood-Derived Mesenchymal Stem Cells for Cartilage Repair and Regeneration: Novel Aspects

Menstrual blood is a unique body fluid that contains mesenchymal stem cells (MSCs). These cells have attracted a great deal of attention due to their exceptional advantages including easy access and frequently accessible sample source and no need for complex ethical and surgical interventions, as compared to other tissues. Menstrual blood-derived MSCs possess all the major stem cell properties and even have a greater proliferation and differentiation potential as compared to bone marrow-derived MSCs, making them a perspective tool in a further clinical practice. Although the potential of menstrual blood stem cells to differentiate into a large variety of tissue cells has been studied in many studies, their chondrogenic properties have not been extensively explored and investigated. Articular cartilage is susceptible to traumas and degenerative diseases, such as osteoarthritis, and has poor self-regeneration capacity and therefore requires more effective therapeutic technique. MSCs seem promising candidates for cartilage regeneration; however, no clinically effective stem cell-based repair method has yet emerged. This chapter focuses on studies in the field of menstrual blood-derived MSCs and their chondrogenic differentiation potential and suitability for application in cartilage regeneration. Although a very limited number of studies have been made in this field thus far, these cells might emerge as an efficient and easily accessible source of multipotent cells for cartilage engineering and cell-based chondroprotective therapy.

The Transcription Factor Hif-1 Enhances the Radio-Resistance of Mouse MSCs

Mesenchymal stromal cells (MSCs) are multipotent progenitors supporting bone marrow hematopoiesis. MSCs have an efficient DNA damage response (DDR) and are consequently relatively radio-resistant cells. Therefore, MSCs are key to hematopoietic reconstitution following total body irradiation (TBI) and bone marrow transplantation (BMT). The bone marrow niche is hypoxic and via the heterodimeric transcription factor Hypoxia-inducible factor-1 (Hif-1), hypoxia enhances the DDR. Using gene knock-down, we have previously shown that the Hif-1α subunit of Hif-1 is involved in mouse MSC radio-resistance, however its exact mechanism of action remains unknown. In order to dissect the involvement of Hif-1α in the DDR, we used CRISPR/Cas9 technology to generate a stable mutant of the mouse MSC cell line MS5 lacking Hif-1α expression. Herein, we show that it is the whole Hif-1 transcription factor, and not only the Hif-1α subunit, that modulates the DDR of mouse MSCs. This effect is dependent upon the presence of a Hif-1α protein capable of binding to both DNA and its heterodimeric partner Arnt (Hif-1β). Detailed transcriptomic and proteomic analysis of Hif1a KO MS5 cells leads us to conclude that Hif-1α may be acting indirectly on the DNA repair process. These findings have important implications for the modulation of MSC radio-resistance in the context of BMT and cancer.

Immunomodulatory effects of foreskin mesenchymal stromal cells on natural killer cells

Foreskin-mesenchymal stromal cells (FSK-MSCs) are immune-privileged thus making them valuable immunotherapeutic cell product. Characterization of the relationship between FSK-MSCs and natural killer (NK) cells is essential to improve cell-based therapy. In the present study, we studied for the first time FSK-MSCs-NK interaction and showed that the result of such cross talk was robustly dependent on the type of cytokines (IL-2, IL-12, IL-15, and IL-21) employed to activate NK cells. Distinctly activated-NK cells showed uneven cytotoxicity against FSK-MSCs, triggering their death in fine. The expression of different cell-surface ligands (CD112, CD155, ULPB-3) and receptors (LAIR, KIRs) ensuring such interaction was altered following co-culture of both populations. Despite their partial negative effect on NK cell proliferation, FSK-MSCs boosted the capacity of activated NK-cells to secrete IFN-γ and TNF-α. Moreover, FSK-MSCs enhanced degranulation of NK cells, reinforced secretion of perforin and granzymes, while only modestly increased ROS production. On the other hand, FSK-MSCs-mediated expression of C1 and B9 serpins was significantly lowered in the presence of activated NK cells. Altogether, our results highlight major immunological changes following FSK-MSCs-NK interaction. Understanding these outcomes will therefore enhance the value of the therapeutic strategy.

Genetically‑modified stem cells in treatment of human diseases: Tissue kallikrein (KLK1)‑based targeted therapy (Review)

The tissue kallikrein-kinin system (KKS) is an endogenous multiprotein metabolic cascade which is implicated in the homeostasis of the cardiovascular, renal and central nervous system. Human tissue kallikrein (KLK1) is a serine protease, component of the KKS that has been demonstrated to exert pleiotropic beneficial effects in protection from tissue injury through its anti-inflammatory, anti-apoptotic, anti-fibrotic and anti-oxidative actions. Mesenchymal stem cells (MSCs) or endothelial progenitor cells (EPCs) constitute populations of well-characterized, readily obtainable multipotent cells with special immunomodulatory, migratory and paracrine properties rendering them appealing potential therapeutics in experimental animal models of various diseases. Genetic modification enhances their inherent properties. MSCs or EPCs are competent cellular vehicles for drug and/or gene delivery in the targeted treatment of diseases. KLK1 gene delivery using adenoviral vectors or KLK1 protein infusion into injured tissues of animal models has provided particularly encouraging results in attenuating or reversing myocardial, renal and cerebrovascular ischemic phenotype and tissue damage, thus paving the way for the administration of genetically modified MSCs or EPCs with the human tissue KLK1 gene. Engraftment of KLK1-modified MSCs and/or KLK1-modified EPCs resulted in advanced beneficial outcome regarding heart and kidney protection and recovery from ischemic insults. Collectively, findings from pre-clinical studies raise the possibility that tissue KLK1 may be a novel future therapeutic target in the treatment of a wide range of cardiovascular, cerebrovascular and renal disorders.

The Roles of ROS in Cancer Heterogeneity and Therapy

Cancer comprises a group of heterogeneous diseases encompassing high rates of morbidity and mortality. Heterogeneity, which is a hallmark of cancer, is one of the main factors related to resistance to chemotherapeutic agents leading to poor prognosis. Heterogeneity is profoundly affected by increasing levels of ROS. Under low concentrations, ROS may function as signaling molecules favoring tumorigenesis and heterogeneity, while under high ROS concentrations, these species may work as cancer modulators due to their deleterious, genotoxic or even proapoptotic effect on cancer cells. This double-edged sword effect represented by ROS relies on their ability to cause genetic and epigenetic modifications in DNA structure. Antitumor therapeutic approaches may use molecules that prevent the ROS formation precluding carcinogenesis or use chemical agents that promote a sudden increase of ROS causing considerable oxidative stress inside tumor mass. Therefore, herein, we review what ROS are and how they are produced in normal and in cancer cells while providing an argumentative discussion about their role in cancer pathophysiology. We also describe the various sources of ROS in cancer and their role in tumor heterogeneity. Further, we also discuss some therapeutic strategies from the current landscape of cancer heterogeneity, ROS modulation, or ROS production.

Human Umbilical Cord Blood Cell Transplantation in Neuroregenerative Strategies

At present there is no effective treatment of pathologies associated with the death of neurons and glial cells which take place as a result of physical trauma or ischemic lesions of the nervous system. Thus, researchers have high hopes for a treatment based on the use of stem cells (SC), which are potentially able to replace dead cells and synthesize neurotrophic factors and other molecules that stimulate neuroregeneration. We are often faced with ethical issues when selecting a source of SC. In addition to precluding these, human umbilical cord blood (hUCB) presents a number of advantages when compared with other sources of SC. In this review, we consider the key characteristics of hUCB, the results of various studies focused on the treatment of neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis), ischemic (stroke) and traumatic injuries of the nervous system and the molecular mechanisms of hUCB-derived mononuclear and stem cells.

In Vivo Tracking of Chemokine Receptor CXCR4-Engineered Mesenchymal Stem Cell Migration by Optical Molecular Imaging

CXCR4, the stromal cell-derived factor-1 receptor, plays an important role in the migration of hematopoietic progenitor/stem cells to injured and inflamed areas. Noninvasive cell tracking methods could be useful for monitoring cell fate. Therefore, in this study, we evaluated the efficacy of an intravenous infusion of genetically engineered mesenchymal stem cells (MSCs) overexpressing CXC chemokine receptor 4 (CXCR4) to home to the tumor, by optical imaging. We constructed a retroviral vector containing CXCR with dual reporter genes, eGFP and Fluc2, under the control of an EF1α promoter (pBABE-EF1α-CXCR4-eGFP-IRES-Fluc2). We also developed an eGFP-Fluc2 construct in the Retro-X retroviral vector (Retro-X-eGFP-Fluc2). MSCs were transduced with retroviruses to generate CXCR4-overexpressing MSCs (MSC-CXCR4/Fluc2) and MSCs (MSC/Fluc2). CXCR4 mRNA and protein expression was confirmed by RT-PCR and Western blotting, respectively, and it was higher in MSC-CXCR4/Fluc2 than in naive MSCs. eGFP expression was confirmed by confocal microscopy. The transfected MSC-CXCR4/Fluc2 cells showed higher migratory capacity than naive MSCs observed in Transwell migration assay. The in vivo migration of CXCR4-overexpressing MSCs to MDAMB231/Rluc tumor model by BLI imaging was also confirmed. Intravenous delivery of genetically modified MSCs overexpressing CXCR4 with a Fluc2 reporter gene may be a useful, noninvasive BLI imaging tool for tracking cell fate.

Mesenchymal Stem Cell Derived Extracellular Vesicles: A Role in Hematopoietic Transplantation?

Mesenchymal stem cells (MSCs) are a heterogeneous cellular population containing different progenitors able to repair tissues, support hematopoiesis, and modulate immune and inflammatory responses. Several clinical trials have used MSCs in allogeneic hematopoietic stem cell transplantation (allo-HSCT) to prevent hematopoietic stem cell (HSC) engraftment failure, reduce aplasia post chemotherapy, and to control graft versus host disease (GvHD). The efficacy of MSCs is linked to their immune suppressive and anti-inflammatory properties primarily due to the release of soluble factors. Recent studies indicate that most of these effects are mediated by extracellular vesicles (EVs). MSC-EVs have therefore therapeutic effects in regenerative medicine, tumor inhibition, and immune-regulation. MSC-EVs may offer specific advantages for patient safety, such as lower propensity to trigger innate and adaptive immune responses. It has been also shown that MSC-EVs can prevent or treat acute-GvHD by modulating the immune-response and, combined with HSCs, may contribute to the hematopoietic microenvironment reconstitution. Finally, MSC-EVs may provide a new potential therapeutic option (e.g., transplantation, gene therapy) for different diseases, particularly hematological malignancies. In this review, we will describe MSC and MSC-EVs role in improving allo-HSCT procedures and in treating GvHD.

Differential Response of Mouse Thymic Epithelial Cell Types to Ionizing Radiation-Induced DNA Damage

Thymic epithelial cells (TECs) are the main components of the thymic stroma that support and control T-cell development. Preparative regimens using DNA-damaging agents, such as total body irradiation and/or chemotherapeutic drugs, that are necessary prior to bone marrow transplantation (BMT) have profound deleterious effects on the hematopoietic system, including the thymic stroma, which may be one of the main causes for the prolonged periods of T-cell deficiency and the inefficient T cell reconstitution that are common following BMT. The DNA damage response (DDR) is a complex signaling network that allows cells to respond to all sorts of genotoxic insults. Hypoxia is known to modulate the DDR and play a role affecting the survival capacity of different cell types. In this study, we have characterized in detail the DDR of cortical and medullary TEC lines and their response to ionizing radiation, as well as the effects of hypoxia on their DDR. Although both mTECs and cTECs display relatively high radio-resistance, mTEC cells have an increased survival capacity to ionizing radiation (IR)-induced DNA damage, and hypoxia specifically decreases the radio-resistance of mTECs by upregulating the expression of the pro-apoptotic factor Bim. Analysis of the expression of TEC functional factors by primary mouse TECs showed a marked decrease of highly important genes for TEC function and confirmed cTECs as the most affected cell type by IR. These findings have important implications for improving the outcomes of BMT and promoting successful T cell reconstitution.

Epigenetic Modification of the CCL5/CCR1/ERK Axis Enhances Glioma Targeting in Dedifferentiation-Reprogrammed BMSCs

The success of stem cell-mediated gene therapy in cancer treatment largely depends on the specific homing ability of stem cells. We have previously demonstrated that after in vitro induction of neuronal differentiation and dedifferentiation, bone marrow stromal cells (BMSCs) revert to a primitive stem cell population (De-neu-BMSCs) distinct from naive BMSCs. We report here that De-neu-BMSCs express significantly higher levels of chemokines, and display enhanced homing abilities to glioma, the effect of which is mediated by the activated CCL5/CCR1/ERK axis. Intriguingly, we find that the activated chemokine axis in De-neu-BMSCs is epigenetically regulated by histone modifications. On the therapeutic front, we show that De-neu-BMSCs elicit stronger homing and glioma-killing effects together with cytosine deaminase/5-fluorocytosine compared with unmanipulated BMSCs in vivo. Altogether, the current study provides an insight into chemokine regulation in BMSCs, which may have more profound effects on BMSC function and their application in regenerative medicine and cancer targeting.

[Efficacy and security of matched unrelated donor hematopoietic stem cell transplant with transfusion of multipotent mesenchymal cells in pediatric severe aplastic anemia]

目的

探讨HLA相合无关供者造血干细胞移植（MUD-HSCT）联合脐带间充质干细胞（MSC）输注治疗儿童重型再生障碍性贫血（SAA）的疗效及安全性。

方法

回顾性分析19例行MUDHSCT联合MSC治疗的儿童SAA患者临床资料，观察移植后造血重建及移植相关并发症。

结果

19例患儿移植后均获得迅速造血重建，粒细胞中位植入时间为12(9~21) d，血小板中位植入时间为14(8~24) d, 1例患儿于移植后4个月出现继发植入失败。9例患儿发生Ⅰ度急性移植物抗宿主病（aGVHD），1例发生Ⅲ度aGVHD并于移植后6个月发生广泛型慢性移植物抗宿主病。CMV阳性15例，出血性膀胱炎2例。10例患儿移植后出现不同程度、不同部位的感染。中位随访时间为27(8~70）个月，19例患儿截至随访终点均无病存活，其中1例患儿于移植后4个月发生淋巴细胞增殖性疾病，接受利妥昔单抗联合化疗治疗后发生继发性植入失败，后接受以父亲为供者的单倍体造血干细胞移植成功植入。

结论

MUD-HSCT联合MSC输注治疗儿童SAA是安全有效的。

Mesenchymal Stem Cells Reversed Morphine Tolerance and Opioid-induced Hyperalgesia

More than 240 million opioid prescriptions are dispensed annually to treat pain in the US. The use of opioids is commonly associated with opioid tolerance (OT) and opioid-induced hyperalgesia (OIH), which limit efficacy and compromise safety. The dearth of effective way to prevent or treat OT and OIH is a major medical challenge. We hypothesized that mesenchymal stem cells (MSCs) attenuate OT and OIH in rats and mice based on the understanding that MSCs possess remarkable anti-inflammatory properties and that both OT and chronic pain are associated with neuroinflammation in the spinal cord. We found that the development of OT and OIH was effectively prevented by either intravenous or intrathecal MSC transplantation (MSC-TP), which was performed before morphine treatment. Remarkably, established OT and OIH were significantly reversed by either intravenous or intrathecal MSCs when cells were transplanted after repeated morphine injections. The animals did not show any abnormality in vital organs or functions. Immunohistochemistry revealed that the treatments significantly reduced activation level of microglia and astrocytes in the spinal cord. We have thus demonstrated that MSC-TP promises to be a potentially safe and effective way to prevent and reverse two of the major problems of opioid therapy.

Human tonsil‑derived mesenchymal stromal cells enhanced myelopoiesis in a mouse model of allogeneic bone marrow transplantation

Mesenchymal stromal cells (MSCs) have therapeutic potential for repairing tissue damage and are involved in immune regulation. MSCs are predominantly isolated from bone marrow (BM), adipose tissue or placental tissue. Further to these well‑known sources, the isolation of MSCs from human tonsils was previously reported. The aim of the present study was to investigate a potential role for tonsil‑derived MSCs (T‑MSCs) in BM reconstitution and application towards supplementing hematopoiesis in a mouse model of BM transplantation (BMT). Eight‑week‑old BALB/c female mice received 80 mg/kg busulfan (Bu)/200 mg/kg cyclophosphamide (Cy) conditioning chemotherapy for BM ablation. Subsequently, human T‑MSCs were injected into the Bu/Cy‑treated mice with or without BM cells (BMCs) obtained from allogeneic C57BL/6 male mice. After 3 weeks, peripheral blood and BM was collected for analysis. The red blood cell count in the group that received BMCs had almost returned to normal, whereas mononuclear cell counts and BM cellularity were most improved in the T‑MSCs + BMCs group. These results indicate that the T‑MSCs enhanced myelopoiesis in the allogeneic BMT mouse model, as evidenced by the restoration of BM with hematopoietic cells, as well as increased myeloid colony formation in vitro. Therefore, T‑MSCs may provide a source of MSCs to facilitate myelopoiesis and megakaryocytosis following BMT.

Immunomodulatory effects of umbilical cord-derived mesenchymal stem cells

Umbilical cord blood (UCB) is of great interest as a source of stem cells for use in cellular therapies. The immunomodulatory effect of mesenchymal stem cells (MSCs) originating from bone marrow, adipose tissue and amniotic membrane has previously been reported. In this study, MSCs were isolated from UCB with the aim of evaluating their immunomodulatory effects on proliferation of PB lymphocytes by two different techniques; namely, 5-bromo-2-deoxyuridine ELISA and a carboxy fluorescein diacetate succinimidyl ester flow cytometric technique. MSCs were isolated from UCB, propagated until Passage four, and then characterized for cell surface markers by flow cytometry and ability to differentiate towards osteocytes and adipocytes. Immunosuppressive effects on PB lymphocytes were examined by co-culturing mitomycin C-treated UCB MSCs with mitogen-stimulated lymphocytes for 72 hr. Thereafter, proliferation of lymphocytes was detected by CFSE flow cytometry and colorimetric ELISA. The titers of cytokines in cell culture supernatant were also assayed to clarify possible mechanisms of immunomodulation. UCB MSCs suppressed mitogen-stimulated lymphocyte proliferation, which occurs via both cell-cell contact and cytokine secretion. Titers of transforming growth factor beta and IL 10 increased, whereas that of IFN-γ decreased in the supernatants of co-cultures. Thus, UCB MSCs suppress the proliferation of mitogen-stimulated lymphocytes. However further in vivo studies are required to fully evaluate the immunomodulatory effects of UCB MSCs.

Neuroprotection and immunomodulation by xenografted human mesenchymal stem cells following spinal cord ventral root avulsion

The present study investigates the effects of xenotransplantation of Adipose Tissue Mesenchymal Stem Cells (AT-MSCs) in animals after ventral root avulsion. AT-MSC has similar characteristics to bone marrow mesenchymal stem cells (BM-MSCs), such as immunomodulatory properties and expression of neurotrophic factors. In this study, Lewis rats were submitted to surgery for unilateral avulsion of the lumbar ventral roots and received 5 × 10(5) AT-MSCs via the lateral funiculus. Two weeks after cell administration, the animals were sacrificed and the moto neurons, T lymphocytes and cell defense nervous system were analyzed. An increased neuronal survival and partial preservation of synaptophysin-positive nerve terminals, related to GDNF and BDNF expression of AT-MSCs, and reduction of pro-inflammatory reaction were observed. In conclusion, AT-MSCs prevent second phase neuronal injury, since they suppressed lymphocyte, astroglia and microglia effects, which finally contributed to rat motor-neuron survival and synaptic stability of the lesioned motor-neuron. Moreover, the survival of the injected AT- MSCs lasted for at least 14 days. These results indicate that neuronal survival after lesion, followed by mesenchymal stem cell (MSC) administration, might occur through cytokine release and immunomodulation, thus suggesting that AT-MSCs are promising cells for the therapy of neuronal lesions.

Hematopoietic Support Capacity of Mesenchymal Stem Cells: Biology and Clinical Potential

Mesenchymal stem cells (MSCs) play an important role in the physiology and homeostasis of the hematopoietic system. Because MSCs generate most of the stromal cells present in the bone marrow (BM), form part of the hematopoietic stem cell (HSC) niche, and produce various molecules regulating hematopoiesis, their hematopoiesis-supporting capacity has been demonstrated. In the last decade, BM-MSCs have been proposed to be useful in some ex vivo protocols for HSC expansion, with the aim of expanding their numbers for transplant purposes (HSC transplant, HSCT). Furthermore, application of MSCs has been proposed as an adjuvant cellular therapy for promoting rapid hematopoietic recovery in HSCT patients. Although the MSCs used in preliminary clinical trials have come from the BM, isolation of MSCs from far more accessible sources such as neonatal tissues has now been achieved, and these cells have been found to possess similar biological characteristics to those isolated from the BM. Therefore, such tissues are now considered as a potential alternative source of MSCs for clinical applications. In this review, we discuss current knowledge regarding the biological characteristics of MSCs as related to their capacity to support the formation of hematopoietic stem and progenitor cells. We also describe MSC manipulation for ex vivo HSC expansion protocols used for transplants and their clinical relevance for hematopoietic recovery in HSCT patients.

In Vitro Evaluation of Scaffolds for the Delivery of Mesenchymal Stem Cells to Wounds

Mesenchymal stem cells (MSCs) have been shown to improve tissue regeneration in several preclinical and clinical trials. These cells have been used in combination with three-dimensional scaffolds as a promising approach in the field of regenerative medicine. We compare the behavior of human adipose-derived MSCs (AdMSCs) on four different biomaterials that are awaiting or have already received FDA approval to determine a suitable regenerative scaffold for delivering these cells to dermal wounds and increasing healing potential. AdMSCs were isolated, characterized, and seeded onto scaffolds based on chitosan, fibrin, bovine collagen, and decellularized porcine dermis. In vitro results demonstrated that the scaffolds strongly influence key parameters, such as seeding efficiency, cellular distribution, attachment, survival, metabolic activity, and paracrine release. Chick chorioallantoic membrane assays revealed that the scaffold composition similarly influences the angiogenic potential of AdMSCs in vivo. The wound healing potential of scaffolds increases by means of a synergistic relationship between AdMSCs and biomaterial resulting in the release of proangiogenic and cytokine factors, which is currently lacking when a scaffold alone is utilized. Furthermore, the methods used herein can be utilized to test other scaffold materials to increase their wound healing potential with AdMSCs.

Adoptive Transfer of Treg Cells Combined with Mesenchymal Stem Cells Facilitates Repopulation of Endogenous Treg Cells in a Murine Acute GVHD Model

Therapeutic effects of combined cell therapy with mesenchymal stem cells (MSCs) and regulatory T cells (Treg cells) have recently been studied in acute graft-versus-host-disease (aGVHD) models. However, the underlying, seemingly synergistic mechanism behind combined cell therapy has not been determined. We investigated the origin of Foxp3+ Treg cells and interleukin 17 (IL-17+) cells in recipients following allogeneic bone marrow transplantation (allo-BMT) to identify the immunological effects of combined cell therapy. Treg cells were generated from eGFP-expressing C57BL/6 mice (Tregegfp cells) to distinguish the transferred Treg cells; recipients were then examined at different time points after BMT. Systemic infusion of MSCs and Treg cells improved survival and GVHD scores, effectively downregulating pro-inflammatory Th×and Th17 cells. These therapeutic effects of combined cell therapy resulted in an increased Foxp3+ Treg cell population. Compared to single cell therapy, adoptively transferred Tregegfp cells only showed prolonged survival in the combined cell therapy group on day 21 after allogeneic BMT. In addition, Foxp3+ Treg cells, generated endogenously from recipients, significantly increased. Significantly higher levels of Tregegfp cells were also detected in aGVHD target organs in the combined cell therapy group compared to the Treg cells group. Thus, our data indicate that MSCs may induce the long-term survival of transferred Treg cells, particularly in aGVHD target organs, and may increase the repopulation of endogenous Treg cells in recipients after BMT. Together, these results support the potential of combined cell therapy using MSCs and Treg cells for preventing aGVHD.