Mesenchymal stem cells alleviate experimental immune-mediated liver injury via chitinase 3-like protein 1-mediated T cell suppression

Liver diseases with different pathogenesis share common pathways of immune-mediated injury. Chitinase-3-like protein 1 (CHI3L1) was induced in both acute and chronic liver injuries, and recent studies reported that it possesses an immunosuppressive ability. CHI3L1 was also expressed in mesenchymal stem cells (MSCs), thus we investigates the role of CHI3L1 in MSC-based therapy for immune-mediated liver injury here. We found that CHI3L1 was highly expressed in human umbilical cord MSCs (hUC-MSCs). Downregulating CHI3L1 mitigated the ability of hUC-MSCs to inhibit T cell activation, proliferation and inflammatory cytokine secretion in vitro. Using Concanavalin A (Con A)-induced liver injury mouse model, we found that silencing CHI3L1 significantly abrogated the hUC-MSCs-mediated alleviation of liver injury, accompanying by weakened suppressive effects on infiltration and activation of hepatic T cells, and secretion of pro-inflammatory cytokines. In addition, recombinant CHI3L1 (rCHI3L1) administration inhibited the proliferation and function of activated T cells, and alleviated the Con A-induced liver injury in mice. Mechanistically, gene set enrichment analysis showed that JAK/STAT signalling pathway was one of the most significantly enriched gene pathways in T cells co-cultured with hUC-MSCs with CHI3L1 knockdown, and further study revealed that CHI3L1 secreted by hUC-MSCs inhibited the STAT1/3 signalling in T cells by upregulating peroxisome proliferator-activated receptor δ (PPARδ). Collectively, our data showed that CHI3L1 was a novel MSC-secreted immunosuppressive factor and provided new insights into therapeutic treatment of immune-mediated liver injury.Subject terms: T cells, Mesenchymal stem cells, Autoimmune hepatitis     

Novel insights for improving the therapeutic safety and efficiency of mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) have attracted great interest in the field of regenerative medicine. They can home to damaged tissue, where they can exert pro-regenerative and anti-inflammatory properties. These therapeutic effects involve the secretion of growth factors, cytokines, and chemokines. Moreover, the functions of MSCs could be mediated by extracellular vesicles (EVs) that shuttle various signaling messengers. Although preclinical studies and clinical trials have demonstrated promising therapeutic results, the efficiency and the safety of MSCs need to be improved. After transplantation, MSCs face harsh environmental conditions, which likely dampen their therapeutic efficacy. A possible strategy aiming to improve the survival and therapeutic functions of MSCs needs to be developed. The preconditioning of MSCs ex vivo would strength their capacities by preparing them to survive and to better function in this hostile environment. In this review, we will discuss several preconditioning approaches that may improve the therapeutic capacity of MSCs. As stated above, EVs can recapitulate the beneficial effects of MSCs and may help avoid many risks associated with cell transplantation. As a result, this novel type of cell-free therapy may be safer and more efficient than the whole cell product. We will, therefore, also discuss current knowledge regarding the therapeutic properties of MSC-derived EVs.     

TNF-α-induced exosomal miR-146a mediates mesenchymal stem cell-dependent suppression of urethral stricture

The effective treatment of urethral stricture remains a medical problem. The use of proinflammatory cytokines as stimuli to improve the reparative efficacy of mesenchymal stem cells (MSCs) towards damaged tissues represents an evolving field of investigation. However, the therapeutic benefits of this strategy in the treatment of urethral stricture remain unknown. Here, we enriched exosomes derived from human umbilical cord-derived MSCs pretreated with or without tumor necrosis factor alpha (TNF-α) to evaluate their therapeutic effects in an in vivo model of TGFβ1-induced urethral stricture. Male Sprague-Dawley rats received sham (saline) or TGFβ1 injections to urethral tissues followed by incisions in the urethra. Animals in the TGFβ1 injection (urethral fibrosis) cohort were subsequently injected with vehicle control, or with exosomes derived from MSCs cultured with or without TNF-α. After 4 weeks, rats underwent ultrasound evaluation and, following euthanasia, urethral tissues were harvested for histological and molecular analysis. In vitro, the effects of MSC-derived exosomes on fibroblast secretion of collagen and cytokines were studied by enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and western blot analysis. Exosomes derived from MSCs pretreated with TNF-α were more effective in suppressing urethral fibrosis and stricture than exosomes from untreated MSCs. We found that miR-146a, an anti-inflammatory miRNA, was strongly upregulated in TNF-α-stimulated MSCs and was selectively packaged into exosomes. Moreover, miR-146a-containing exosomes were taken up by fibroblasts and inhibited fibroblast activation and associated inflammatory responses, a finding that may underlie the therapeutic mechanism for suppression of urethral stricture. Inhibition of miR-146a in TNF-α-treated MSCs partially reduced antifibrotic effects and increased the release of proinflammatory factors of exosomes derived from these cells. Together these findings demonstrate that exosomes derived from TNF-α-treated MSCs are of therapeutic benefit in urethral fibrosis, suggesting that this strategy may have utility as an adjuvant therapy in the treatment of urethral stricture diseases.     

Potential surrogate quantitative immunomodulatory potency assay for monitoring human umbilical cord-derived mesenchymal stem cells production

Mesenchymal stem cells (MSCs) play an important role as immune modulator through interaction with several immune cells, including macrophages. In this study, the immunomodulatory potency of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) was demonstrated in the in vivo middle cerebral artery occlusion (MCAo)-induced brain injury rat model and in vitro THP-1-derived macrophages model. At 24 h after induction of MCAo, hUC-MSCs was administered via tail vein as a single dose. Remarkably, hUC-MSCs could inhibit M1 polarization and promote M2 polarization of microglia in vivo after 14 days induction of MCAo. Compared with THP-1-derived macrophages which had been stimulated by lipopolysaccharide, the secretion of proinflammatory cytokines, tumor necrosis factor-α (TNF-α) and interferon-γ inducible protein (IP-10), were significantly reduced in the presence of hUC-MSCs. Moreover, the secretion of anti-inflammatory cytokine, interleukin-10 (IL-10), was significantly increased after cocultured with hUC-MSCs. Prostaglandins E2 (PGE2), secreted by hUC-MSCs, is one of the crucial immunomodulatory factors and could be inhibited in the presence of COX2 inhibitor, NS-398. PGE2 inhibition suppressed hUC-MSCs immunomodulatory capability, which was restored after addition of synthetic PGE2, establishing the minimum amount of PGE2 required for immunomodulation. In conclusion, our data suggested that PGE2 is a crucial potency marker involved in the therapeutic activity of hUC-MSCs through macrophages immune response modulation and cytokines regulation. This study provides the model for the development of a surrogate quantitative potency assay of immunomodulation in stem cells production.     

Effects of chlorogenic acid,caffeine, and coffee on behavioral and biochemical parameters of diabetic rats

Mesenchymal stem cells (MSCs) represent a potential therapeutic target for glioma. We determined the molecular mechanism of inhibitory effect of human umbilical cord-derived MSCs (hUC-MSCs) on the growth of C6 glioma cells. We demonstrated that hUC-MSCs inhibited C6 cell growth and modulated the cell cycle to G0/G1 phase. The expression of β-catenin and c-Myc was downregulated in C6 cells by conditioned media from hUC-MSCs, and the levels of secreted DKK1 were positively correlated with concentrations of hUCMSCs-CM. The inhibitory effect of hUC-MSCs on C6 cell proliferation was enhanced as the concentration of DKK1 in hUCMSCs-CM increased. When DKK1 was neutralized by anti-DKK1 antibody, the inhibitory effect of hUC-MSCs on C6 cells was attenuated. Furthermore, we found that conditioned media from hUC-MSCs transfection with siRNA targeting DKK1 mRNA or pEGFPN1-DKK1 plasmid lost or enhanced the abilities to regulate the Wnt signaling in C6 cells. Therefore, hUC-MSCs inhibited C6 glioma cell growth via secreting DKK1, an inhibitor of Wnt pathway, may represent a novel therapeutic strategy for malignant glioma.     

Strategies to improve the efficiency of mesenchymal stem cell transplantation for reversal of liver fibrosis

End‐stage liver fibrosis frequently progresses to portal vein thrombosis, formation of oesophageal varices, hepatic encephalopathy, ascites, hepatocellular carcinoma and liver failure. Mesenchymal stem cells (MSCs), when transplanted in vivo, migrate into fibrogenic livers and then differentiate into hepatocyte‐like cells or fuse with hepatocytes to protect liver function. Moreover, they can produce various growth factors and cytokines with anti‐inflammatory effects to reverse the fibrotic state of the liver. In addition, only a small number of MSCs migrate to the injured tissue after cell transplantation; consequently, multiple studies have investigated effective strategies to improve the survival rate and activity of MSCs for the treatment of liver fibrosis. In this review, we intend to arrange and analyse the current evidence related to MSC transplantation in liver fibrosis, to summarize the detailed mechanisms of MSC transplantation for the reversal of liver fibrosis and to discuss new strategies for this treatment. Finally, and most importantly, we will identify the current problems with MSC‐based therapies to repair liver fibrosis that must be addressed in order to develop safer and more effective routes for MSC transplantation. In this way, it will soon be possible to significantly improve the therapeutic effects of MSC transplantation for liver regeneration, as well as enhance the quality of life and prolong the survival time of patients with liver fibrosis.     

人滑膜间充质干细胞与人脐带间充质干细胞的生物学性状比较

该文旨在比较人滑膜间充质干细胞(human synovial mesenchymal stem cells,hSMSCs)与人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,hUC-MSCs)的生物学性状。流式细胞仪鉴定hSMSCs和hUC-MSCs。比较两种间充质干细胞的增殖、分化、迁移能力。结果表明,hSMSCs和hUC-MSCs均为长梭形贴壁细胞,并表达多种间充质干细胞表面标志物。不同的是,hUC-MSCs高表达CD73、CD105、CD147;而hSMSCs高表达CD24。hSMSCs具有更强的早期成骨和成软骨能力。hUC-MSCs具有更强的增殖和迁移能力,细胞周期结果显示,hSMSCs和hUC-MSCs均具有较强的增殖能力。该研究成功分离出hSMSCs,其生物学性状与hUC-MSCs相似,且具有较强的成骨与成软骨能力,可作为组织工程的理想种子细胞或临床治疗用细胞。     

Effects of living and metabolically inactive mesenchymal stromal cells and their derivatives on monocytes and macrophages

Mesenchymal stromal cells(MSCs) are multipotent and self-renewing stem cells that have great potential as cell therapy for autoimmune and inflammatory disorders, as well as for other clinical conditions, due to their immunoregulatory and regenerative properties. MSCs modulate the inflammatory milieu by releasing soluble factors and acting through cell-to-cell mechanisms. MSCs switch the classical inflammatory status of monocytes and macrophages towards a nonclassical and anti-inflammatory phenotype. This is characterized by an increased secretion of anti-inflammatory cytokines, a decreased release of pro-inflammatory cytokines, and changes in the expression of cell membrane molecules and in metabolic pathways. The MSC modulation of monocyte and macrophage phenotypes seems to be critical for therapy effectiveness in several disease models, since when these cells are depleted, no immunoregulatory effects are observed. Here, we review the effects of living MSCs(metabolically active cells) and metabolically inactive MSCs(dead cells that lost metabolic activity by induced inactivation) and their derivatives(extracellular vesicles, soluble factors, extracts, and microparticles) on the profile of macrophages and monocytes and the implications for immunoregulatory and reparative processes. This review includes mechanisms of action exhibited in these different therapeutic appro-aches, which induce the antiinflammatory properties of monocytes and macrophages. Finally, we overview several possibilities of therapeutic applications of these cells and their derivatives, with results regarding monocytes and macrophages in animal model studies and some clinical trials.     

骨髓间充质干细胞抗肝纤维化的研究进展

肝纤维化及其终末病变肝硬化已严重危害全球人类健康,虽然慢性肝病的治疗手段和抗肝纤维化药物的研究已取得了很大进展,肝移植依然是最有效的治疗方案,但器官的紧缺却是一个现实问题。目前寻找有效的干预手段进行抗肝纤维化治疗已越来越受到大家的关注。近些年,大量基础及临床研究均证实在一定条件下利用骨髓间充质干细胞(MSCs)可以抑制肝星状细胞活化诱导其凋亡,实现肝纤维化逆转。随着干细胞技术的快速发展,基于骨髓间充质干细胞(MSCs)的细胞疗法在肝纤维化治疗领域的研究与应用已成为一个充满生命力的新方向。本文将对肝纤维化及基于MSCs的治疗机制进展及其应用进行综述。     

Progress in the use of mesenchymal stromal cells for osteoarthritis treatment

Literature review of MSCs in the treatment of osteoarthritis in the past five yearsOsteoarthritis (OA) is one of the most common chronic joint diseases, with prominent symptoms caused by many factors. However, current medical interventions for OA have resulted in poor clinical outcomes, demonstrating that there are huge unmet medical needs in this area. Cell therapy has opened new avenues of OA treatment. Different sources of mesenchymal stromal cells (MSCs) may have different phenotypes and cellular functions. Pre-clinical and clinical studies have demonstrated the feasibility, safety and efficacy of MSC therapy. Mitogen-activated protein kinase, Wnt and Notch signaling pathways are involved in the chondrogenesis of MSC-mediated treatments. MSCs may also exert effective immunoregulatory and paracrine effects to stimulate tissue repair. Therapy with extracellular vesicles containing cytokines, which are secreted by MSCs, might be a potential treatment for OA.     

Isolation and Characterization of a Novel Strain of Mesenchymal Stem Cells from Mouse Umbilical Cord: Potential Application in Cell-Based Therapy

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) have recently been recognized as a potential source for cell-based therapy in various preclinical animal models, such as Parkinson’s disease, cerebral ischemia, spinal cord injury, and liver failure; however, the precise cellular and molecular mechanisms underlying the beneficial outcomes remain under investigation. There is a growing concern regarding rejection and alteration of genetic code using this xenotransplantation approach. In this study, a novel strain of murine MSCs derived from the umbilical cord of wild-type and green fluorescent protein (GFP) transgenic mice have been successfully isolated, expanded, and characterized. After 10 passages, the mUC-MSCs developed a rather homogeneous, triangular, spindle-shaped morphology, and were sub-cultured up to 7 months (over 50 passages) without overt changes in morphology and doubling time. Cell surface markers are quite similar to MSCs isolated from other tissue origins as well as hUC-MSCs. These mUC-MSCs can differentiate into osteoblasts, adipocytes, neurons, and astrocytes in vitro, as well as hematopoietic lineage cells in vivo. mUC-MSCs also possess therapeutic potential against two disease models, focal ischemic stroke induced by middle cerebral artery occlusion (MCAo) and acute hepatic failure. Subtle differences in the expression of cytokine-related genes exist between mUC-MSCs and hUC-MSCs, which may retard and jeopardize the advance of cell therapy. Allografts of these newly established mUC-MSCs into various mouse disease models may deepen our insights into the development of more effective cell therapy regimens.     

Human mesenchymal stromal cell proteomics: contribution for identification of new markers and targets for medicine intervention

Mesenchymal stem or stromal cells (MSCs) have become of great interest for cell-based therapy owing to their roles in tissue repair and immune suppression. MSCs have the ability to differentiate into specialized tissues, including bone, cartilage and muscle, among several others. Furthermore, it has been found that MSCs can also serve as cellular factories that secrete mediators to stimulate in situ regeneration of injured tissues. Proteomics has contributed significantly to the identification of new proteins to improve cellular characterization of MSCs, to identify new targets for therapeutic intervention and to elucidate important pathways utilized by MSCs to differentiate into distinct tissues. As proteomics technology advances, several studies can be revisited and analyzed in depth, employing state-of-the-art approaches, helping to uncover the cellular mechanisms utilized by MSCs to exert their regenerative functionalities. In this article, we will review the progress made so far and discuss further opportunities for proteomics to contribute to the clinical applications of MSCs.     

Mesenchymal stromal cells as potential immunomodulatory players in severe acute respiratory distress syndrome induced by SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus-2 and the related coronavirus disease-19 (COVID-19) is a worldwide emerging situation, which was initially reported in December 2019 in Wuhan, China. Currently, more than 7258842 new cases, and more than 411879 deaths have been reported globally. This new highly transmitted coronavirus is responsible for the development of severe acute respiratory distress syndrome. Due to this disorder, a great number of patients are hospitalized in the intensive care unit followed by connection to extracorporeal membrane oxygenation for breath supporting and survival. Severe acute respiratory distress syndrome is mostly accompanied by the secretion of proinflammatory cytokines, including interleukin (IL)-2, IL-6, IL-7, granulocyte colony-stimulating factor (GSCF), interferon-inducible protein 10 (IP10), monocyte chemotactic protein-1 (MCP1), macrophage inflammatory protein 1A (MIP1A), and tumor necrosis factor alpha (TNF-α), an event which is known as “cytokine storm”. Further disease pathology involves a generalized modulation of immune responses, leading to fatal multiorgan failure. Currently, no specific treatment or vaccination against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been developed. Mesenchymal stromal cells (MSCs), which are known for their immunosuppressive actions, could be applied as an alternative co-therapy in critically-ill COVID-19 patients. Specifically, MSCs can regulate the immune responses through the conversion of Th1 to Th2, activation of M2 macrophages, and modulation of dendritic cells maturation. These key immunoregulatory properties of MSCs may be exerted either by produced soluble factors or by cell-cell contact interactions. To date, several clinical trials have been registered to assess the safety, efficacy, and therapeutic potential of MSCs in COVID-19. Moreover, MSC treatment may be effective for the reversion of ground-glass opacity of damaged lungs and reduce the tissue fibrosis. Taking into account the multifunctional properties of MSCs, the proposed stem-cell-based therapy may be proven significantly effective in critically-ill COVID-19 patients. The current therapeutic strategy may improve the patient’s overall condition and in parallel may decrease the mortality rate of the current disease.     

Review of the potential of mesenchymal stem cells for the treatment of infectious diseases

The therapeutic value of mesenchymal stem cells (MSCs) for the treatment of infectious diseases and the repair of disease-induced tissue damage has been explored extensively. MSCs inhibit inflammation, reduce pathogen load and tissue damage encountered during infectious diseases through the secretion of antimicrobial factors for pathogen clearance and they phagocytose certain bacteria themselves. MSCs dampen tissue damage during infection by downregulating the levels of pro-inflammatory cytokines, and inhibiting the excessive recruitment of neutrophils and proliferation of T cells at the site of injury. MSCs aid in the regeneration of damaged tissue by differentiating into the damaged cell types or by releasing paracrine factors that direct tissue regeneration, differentiation, and wound healing. In this review, we discuss in detail the various mechanisms by which MSCs help combat pathogens, tissue damage associated with infectious diseases, and challenges in utilizing MSCs for therapy.     

Could co‐transplantation of iPS cells derived hepatocytes and MSCs cure end‐stage liver disease?

Orthotopic liver transplantation is, to date, the only proven effective treatment for end-stage liver disease. However, it suffers from lack of donors and immunorejection. Here, we speculate that co-transplantation of induced pluripotent stem (iPS) cells derived hepatocytes and mesenchymal stem cells (MSCs) may offer an alternative way to treat patients with end-stage liver disease. Recently, progress on iPS cells, homogeneous differentiation of hepatocyte-like cells from embryonic stem cells (ESCs), and paracrine effects by MSCs highlight the possibility. Safe, efficient and rapid generation of iPS cells has been reliably produced by several experimental laboratories. Methods for highly efficient and homogeneous differentiation of ESCs into functional hepatocytes have been established as well. Moreover, paracrine effects by MSCs have been proven to play an important role in liver regeneration and repair, and the effects can be used as an enhancer for engraftment. All of these remarkable developments lead to this hypothesis which may offer a novel therapeutic strategy for treatment of patients with end-stage liver disease, though some issues about safety and efficacy need to be further guaranteed.     

Application of human bone marrow-derived mesenchymal stem cells in the treatment of radiation-induced gastrointestinal syndrome

Nuclear accidents and terrorism present a serious threat for mass casualty.Accidental or intended radiation exposure leads to radiation-induced gastrointestinal(GI)syndrome.However,currently there are no approved medical countermeasures for GI syndrome.Thus,developing novel treatments for GI syndrome is urgent.Mesenchymal stem cells(MSCs)derived from bone marrow are a subset of multipotent adult somatic stem cells that have the ability to undergo self-renewal,proliferation and pluripotent differentiation.MSCs have advantages over other stem cells;they can be easily isolated from patients or donors,readily expanded ex vivo,and they possess reparative and immunomodulatory properties.Moreover,MSCs have been shown to be powerful tools in gene therapy and can be effectively transduced with vectors containing therapeutic genes.Therefore,the therapeutic potential of MSCs has been brought into the spotlight for the clinical treatment of GI syndrome.In this review,we discuss the possible role of MSCs in radiation-induced GI syndrome.