Human ESC-derived MSCs outperform bone marrow MSCs in the treatment of an EAE model of multiple sclerosis

Mesenchymal Stromal Cells Increase the Natural Killer Resistance of Circulating Tumor Cells via Intercellular Signaling of cGAS-STING-IFNβ-HLA

Circulating tumor cells (CTCs) shed from primary tumors must overcome the cytotoxicity of immune cells, particularly natural killer (NK) cells, to cause metastasis. The tumor microenvironment (TME) protects tumor cells from the cytotoxicity of immune cells, which is partially executed by cancer-associated mesenchymal stromal cells (MSCs). However, the mechanisms by which MSCs influence the NK resistance of CTCs remain poorly understood. This study demonstrates that MSCs enhance the NK resistance of cancer cells in a gap junction-dependent manner, thereby promoting the survival and metastatic seeding of CTCs in immunocompromised mice. Tumor cells crosstalk with MSCs through an intercellular cGAS-cGAMP-STING signaling loop, leading to increased production of interferon-β (IFNβ) by MSCs. IFNβ reversely enhances the type I IFN (IFN-I) signaling in tumor cells and hence the expression of human leukocyte antigen class I (HLA-I) on the cell surface, protecting the tumor cells from NK cytotoxicity. Disruption of this loop reverses NK sensitivity in tumor cells and decreases tumor metastasis. Moreover, there are positive correlations between IFN-I signaling, HLA-I expression, and NK tolerance in human tumor samples. Thus, the NK-resistant signaling loop between tumor cells and MSCs may serve as a novel therapeutic target.

Mesenchymal stem/stromal cells from human pluripotent stem cell-derived brain organoid enhance the ex vivo expansion and maintenance of hematopoietic stem/progenitor cells

BACKGROUND

Mesenchymal stem/stromal cells (MSCs) are of great therapeutic value due to their role in maintaining the function of hematopoietic stem/progenitor cells (HSPCs). MSCs derived from human pluripotent stem cells represent an ideal alternative because of their unlimited supply. However, the role of MSCs with neural crest origin derived from HPSCs on the maintenance of HSPCs has not been reported.

METHODS

Flow cytometric analysis, RNA sequencing and differentiation ability were applied to detect the characteristics of stromal cells from 3D human brain organoids. Human umbilical cord blood CD34+ (UCB-CD34+) cells were cultured in different coculture conditions composed of stromal cells and umbilical cord MSCs (UC-MSCs) with or without a cytokine cocktail. The hematopoietic stroma capacity of stromal cells was tested in vitro with the LTC-IC assay and in vivo by cotransplantation of cord blood nucleated cells and stroma cells into immunodeficient mice. RNA and proteomic sequencing were used to detect the role of MSCs on HSPCs.

RESULTS

The stromal cells, derived from both H1-hESCs and human induced pluripotent stem cells forebrain organoids, were capable of differentiating into the classical mesenchymal-derived cells (osteoblasts, chondrocytes, and adipocytes). These cells expressed MSC markers, thus named pluripotent stem cell-derived MSCs (pMSCs). The pMSCs showed neural crest origin with CD271 expression in the early stage. When human UCB-CD34+ HSPCs were cocultured on UC-MSCs or pMSCs, the latter resulted in robust expansion of UCB-CD34+ HSPCs in long-term culture and efficient maintenance of their transplantability. Comparison by RNA sequencing indicated that coculture of human UCB-CD34+ HSPCs with pMSCs provided an improved microenvironment for HSC maintenance. The pMSCs highly expressed the Wnt signaling inhibitors SFRP1 and SFRP2, indicating that they may help to modulate the cell cycle to promote the maintenance of UCB-CD34+ HSPCs by antagonizing Wnt activation.

CONCLUSIONS

A novel method for harvesting MSCs with neural crest origin from 3D human brain organoids under serum-free culture conditions was reported. We demonstrate that the pMSCs support human UCB-HSPC expansion in vitro in a long-term culture and the maintenance of their transplantable ability. RNA and proteomic sequencing indicated that pMSCs provided an improved microenvironment for HSC maintenance via mechanisms involving cell-cell contact and secreted factors and suppression of Wnt signaling. This represents a novel method for large-scale production of MSCs of neural crest origin and provides a potential approach for development of human hematopoietic stromal cell therapy for treatment of dyshematopoiesis.

miR-100a-5p-enriched exosomes derived from mesenchymal stem cells enhance the anti-oxidant effect in a Parkinson's disease model via regulation of Nox4/ROS/Nrf2 signaling

BACKGROUND

The pathogenesis of Parkinson's disease (PD) has not been fully elucidated, and there are no effective disease-modifying drugs for the treatment of PD. Mesenchymal stem cells have been used to treat several diseases, but are not readily available.

METHODS

Here, we used phenotypically uniform trophoblast stage-derived mesenchymal stem cells (T-MSCs) from embryonic stem cells, which are capable of stable production, and their exosomes (T-MSCs-Exo) to explore the molecular mechanisms involved in dopaminergic (DA) neuron protection in PD models using experimental assays (e.g., western blotting, immunofluorescence and immunohistochemistry staining).

RESULTS

We assessed the levels of DA neuron injury and oxidative stress in MPTP-induced PD mice and MPP+-induced MN9D cells after treating them with T-MSCs or T-MSCs-Exo. Furthermore, T-MSCs-Exo miRNA sequencing analysis revealed that miR-100-5p-enriched T-MSCs-Exo directly targeted the 3' UTR of NOX4, which could protect against the loss of DA neurons, maintain nigro-striatal system function, ameliorate motor deficits, and reduce oxidative stress via the Nox4-ROS-Nrf2 axis in PD models.

CONCLUSIONS

The study suggests that miR-100-5p-enriched T-MSCs-Exo may be a promising biological agent for the treatment of PD. Schematic summary of the mechanism underlying the neuroprotective actions of T-MSCs-Exo in PD. T-MSCs Exo may inhibit the expression level of the target gene NOX4 by delivering miR-100-5p, thereby reducing ROS production and alleviating oxidative stress via the Nox4-ROS-Nrf2 axis, thus improving DA neuron damage in PD.

Mesodermal Derivatives of Pluripotent Stem Cells Route to Scarless Healing

Scar formation during normal tissue regeneration in adults may result in noticeable cosmetic and functional defects and have a significant impact on the quality of life. In contrast, fetal tissues in the mid-gestation period are known to be capable of complete regeneration with the restitution of the initial architecture, organization, and functional activity. Successful treatments that are targeted to minimize scarring can be realized by understanding the cellular and molecular mechanisms of fetal wound regeneration. However, such experiments are limited by the inaccessibility of fetal material for comparable studies. For this reason, the molecular mechanisms of fetal regeneration remain unknown. Mesenchymal stromal cells (MSCs) are central to tissue repair because the molecules they secrete are involved in the regulation of inflammation, angiogenesis, and remodeling of the extracellular matrix. The mesodermal differentiation of human pluripotent stem cells (hPSCs) recapitulates the sequential steps of embryogenesis in vitro and provides the opportunity to generate the isogenic cell models of MSCs corresponding to different stages of human development. Further investigation of the functional activity of cells from stromal differon in a pro-inflammatory microenvironment will procure the molecular tools to better understand the fundamental mechanisms of fetal tissue regeneration. Herein, we review recent advances in the generation of clonal precursors of primitive mesoderm cells and MSCs from hPSCs and discuss critical factors that determine the functional activity of MSCs-like cells in a pro-inflammatory microenvironment in order to identify therapeutic targets for minimizing scarring.

Mesenchymal stem cell-derived exosomes attenuate DNA damage response induced by cisplatin and bleomycin

Stem cell-derived exosomes (SC-Exos) have been shown to protect cells from chemical-induced deoxyribonucleic acid (DNA) damage. However, there has been no systematic comparison of the efficacy of exosomes against different types of DNA damage. Therefore, in this study, we assessed the protective effect of exosomes derived from human embryonic stem cell-induced mesenchymal stem cells (hESC-MSC-Exos) on two types of DNA damage, namely, intra-/inter-strand crosslinks and DNA double-strand breaks induced by cisplatin (Pt) and bleomycin (BLM), respectively, in HeLa cells. The alkaline comet assay demonstrated that hESC-MSC-Exos effectively inhibited Pt- and BLM-induced DNA damage in a dose-dependent manner. When the concentration of hESC-MSC-Exos reaches 2.0 × 10⁶ and 4.0 × 10⁶ particles/mL in Pt- and BLM-treated groups, respectively, there was a significant decrease in tail DNA percentage (Pt: 20.80 ± 1.61 vs 9.40 ± 1.14, p < 0.01; BLM: 21.80 ± 1.31 vs 6.70 ± 0.60, p < 0.01), tail moment (Pt: 10.00 ± 1.21 vs 2.08 ± 0.51, p < 0.01; BLM: 12.00 ± 0.81 vs 2.00 ± 0.21, p < 0.01), and olive tail moment (Pt: 6.01 ± 0.55 vs 2.09 ± 0.25, p < 0.01; BLM: 6.03 ± 0.37 vs 1.53 ± 0.13, p < 0.01). Phospho-histone H2AX (γH2AX) immunofluorescence and western blotting showed an over 50 % decrease in γH2AX expression when the cells were pretreated with hESC-MSC-Exos. As reactive oxygen species (ROS) are important mediators of Pt- and BLM-induced DNA damage, dichloro-dihydro-fluorescein diacetate staining indicated that hESC-MSC-Exos inhibited the increase in intracellular ROS in drug-treated cells. In conclusion, our findings suggest that hESC-MSC-Exos can protect cells from the two types of DNA-damaging drugs and that reduced intracellular ROS is involved in this effect.

Mesenchymal stem cell-derived extracellular vesicles subvert Th17 cells by destabilizing RORγt through posttranslational modification

Mesenchymal stem cell (MSC)-derived small extracellular vesicles (MSC-sEVs) are known to exert immunosuppressive functions. This study showed that MSC-sEVs specifically convert T helper 17 (Th17) cells into IL-17 low-producer (ex-Th17) cells by degrading RAR-related orphan receptor γt (RORγt) at the protein level. In experimental autoimmune encephalomyelitis (EAE)-induced mice, treatment with MSC-sEVs was found to not only ameliorate clinical symptoms but also to reduce the number of Th17 cells in draining lymph nodes and the central nervous system. MSC-sEVs were found to destabilize RORγt by K63 deubiquitination and deacetylation, which was attributed to the EP300-interacting inhibitor of differentiation 3 (Eid3) contained in the MSC-sEVs. Small extracellular vesicles isolated from the Eid3 knockdown MSCs by Eid3-shRNA failed to downregulate RORγt. Moreover, forced expression of Eid3 by gene transfection was found to significantly decrease the protein level of RORγt in Th17 cells. Altogether, this study reveals the novel immunosuppressive mechanisms of MSC-sEVs, which suggests the feasibility of MSC-sEVs as an attractive therapeutic tool for curing Th17-mediated inflammatory diseases.

Efficacy of Human Embryonic Stem Cells Compared to Adipose Tissue-Derived Human Mesenchymal Stem/Stromal Cells for Repair of Murine Post-Stenotic Kidneys

Clinical translation of mesenchymal stem/stromal cell (MSC) therapy has been impeded by the heterogenous nature and limited replicative potential of adult-derived MSCs. Human embryonic stem cell-derived MSCs (hESC-MSCs) that differentiate from immortal cell lines are phenotypically uniform and have shown promise in-vitro and in many disease models. Similarly, adipose tissue-derived MSCs (MSC(AT)) possess potent reparative properties. How these two cell types compare in efficacy, however, remains unknown. We randomly assigned mice to six groups (n = 7-8 each) that underwent unilateral RAS or a sham procedure (3 groups each). Two weeks post-operation, each mouse was administered either vehicle, MSC(AT)s, or hESC-MSCs (5 × 105 cells) into the aorta. Mice were scanned with micro-MRI to determine renal hemodynamics two weeks later and kidneys then harvested. hESC-MSCs and MSC(AT)s were similarly effective at lowering systolic blood pressure. However, MSC(AT)s more robustly increased renal perfusion, oxygenation, and glomerular filtration rate in the post-stenotic kidney, and more effectively mitigated tubular injury, fibrosis, and vascular remodeling. These observations suggest that MSC(AT) are more effective than hESC-MSC in ameliorating kidney dysfunction and tissue injury distal to RAS. Our findings highlight the importance of tissue source in selection of MSCs for therapeutic purposes and underscore the utility of cell-based therapy for kidney disease.

Distribution of Embryonic Stem Cell-Derived Mesenchymal Stem Cells after Intravenous Infusion in Hypoxic-Ischemic Encephalopathy

Systemic administration of mesenchymal stem cells (MSCs) has been reported to improve neurological function in brain damage, including hypoxic-ischemic encephalopathy (HIE), though the action mechanisms have not been fully elucidated. In this study, the cells were tracked live using a Pearl Trilogy Small Animal fluorescence imaging system after human embryonic stem Cell-Derived MSCs (ES-MSCs) infusion for an HIE mouse model. ES-MSC-treated HIE mice showed neurobehavioral improvement. In vivo imaging showed similar sequential migration of ES-MSCs from lungs, liver, and spleen within 7 days in both HIE and normal mice with the exception of lungs, where there was higher entrapment in the HIE 1 h after infusion. In addition, ex vivo experiments confirmed time-dependent infiltration of ES-MSCs into the organs, with similar findings in vivo, although lungs and brain revealed small differences. ES-MSCs seemed to remain in the brain only in the case of HIE on day 14 after the cell infusion. The homing effect in the host brain was confirmed with immunofluorescence staining, which showed that grafted cells remained in the brain tissue at the lesion area with neurorestorative findings. Further research should be carried out to elucidate the role of each host organ's therapeutic effects when stem cells are systemically introduced.

Use of Mesenchymal Stem Cells in Crohn's Disease and Perianal Fistulas: A Narrative Review

Crohn's Disease (CD), which usually leads to anal fistulas among patients, is the most important inflammatory bowel disease that causes morbidity in many people around the world. This review article proposes using MSCs as a hopeful therapeutic strategy for CD and anal fistula treatment in both preclinical and clinical conditions. Finally, darvadstrocel, a cell-based medication to treat complex anal fistulas in adults, as the only European Medicines Agency (EMA)-approved product for the treatment of anal fistulas in CD is addressed. Although several common therapies, such as surgery and anti-tumor necrosis factor-alpha (TNF-α) drugs as well as a combination of these methods is used to improve this disease, however, due to the low effectiveness of these treatments, the use of new strategies with higher efficiency is still recommended. Cell therapy is among the new emerging therapeutic strategies that have attracted great attention from clinicians due to its unique capabilities. One of the most widely used cell sources administrated in cell therapy is mesenchymal stem cell (MSC). This review article will discuss preclinical and clinical studies about MSCs as a potent and promising therapeutic option in the treatment of CD and anal fistula.

Mesenchymal Stem Cell Therapy for Huntington Disease: A Meta-Analysis

Objective

Mesenchymal stem cell (MSC) therapy has been explored in Huntington disease (HD) as a potential therapeutic approach; however, a complete synthesis of these results is lacking. We conducted a meta-analysis to evaluate the effects of MSCs on HD.

Method

Eligible studies published before November 2022 were screened from Embase, PubMed, Web of Science, Medline, and Cochrane in accordance with PRISMA guidelines. ClinicalTrial.gov and the World Health Organization International Clinical Trials Registry Platform were also searched for registered clinical trials. The outcomes in rodent studies evaluated included morphological changes (striatal volume and ventricular volume), motor function (rotarod test, wire hang test, grip strength test, limb-clasping test, apomorphine-induced rotation test, and neuromuscular electromyography activity), cognition (Morris water maze test), and body weight.

Result

The initial search returned 362 records, of which 15 studies incorporating 346 HD rodents were eligible for meta-analysis. Larger striatal and smaller ventricular volumes were observed in MSC-treated animals compared to controls. MSCs transplanted before the occurrence of motor dysfunction rescued the motor incoordination of HD. Among different MSC sources, bone marrow mesenchymal stem cells were the most investigated cells and were effective in improving motor coordination. MSC therapy improved muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed. The body weight of male HD rodents increased after MSC transplantation, while that of females was not affected.

Conclusion

Meta-analysis showed a positive effect of MSCs on HD rodents overall, as reflected in morphological changes, motor coordination, muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed by MSC therapy.

Embryonic stem cell-derived mesenchymal stem cells alleviate skeletal muscle injury induced by acute compartment syndrome

Background

Acute compartment syndrome (ACS), a well-known complication of musculoskeletal injury, results in muscle necrosis and cell death. Embryonic stem cell-derived mesenchymal stem cells (ESC-MSCs) have been shown to be a promising therapy for ACS. However, their effectiveness and potentially protective mechanism remain unknown. The present study was designed to investigate the efficacy and underlying mechanism of ESC-MSCs in ACS-induced skeletal muscle injury.

Method

A total of 168 male Sprague–Dawley (SD) rats underwent 2 h of intracompartmental pressure elevation by saline infusion into the anterior compartment of the left hindlimb to establish the ACS model. ESC-MSCs were differentiated from the human embryonic stem cell (ESC) line H9. A dose of 1.2 × 10⁶ of ESC-MSCs was intravenously injected during fasciotomy. Post-ACS assessments included skeletal edema index, serum indicators, histological analysis, apoptosis, fibrosis, regeneration, and functional recovery of skeletal muscle. Then, fluorescence microscopy was used to observe the distribution of labeled ESC-MSCs in vivo, and western blotting and immunofluorescence analyses were performed to examine macrophages infiltration in skeletal muscle. Finally, we used liposomal clodronate to deplete macrophages and reassess skeletal muscle injury in response to ESC-MSC therapy.

Result

ESC-MSCs significantly reduced systemic inflammatory responses, ACS-induced skeletal muscle edema, and cell apoptosis. In addition, ESC-MSCs inhibited skeletal muscle fibrosis and increased regeneration and functional recovery of skeletal muscle after ACS. The beneficial effects of ESC-MSCs on ACS-induced skeletal muscle injury were accompanied by a decrease in CD86-positive M1 macrophage polarization and an increase in CD206-positive M2 macrophage polarization. After depleting macrophages with liposomal clodronate, the beneficial effects of ESC-MSCs were attenuated.

Conclusion

Our findings suggest that embryonic stem cell-derived mesenchymal stem cells infusion could effectively alleviate ACS-induced skeletal muscle injury, in which the beneficial effects were related to the regulation of macrophages polarization.

Hippocampal neuroprotection mediated by secretome of human mesenchymal stem cells against experimental stroke

Aims

Regenerative medicine literature has demonstrated that the therapeutic potentials of mesenchymal stem cells (MSCs) in experimental stroke are attributed to secreted bioactive factors rather than to cell replacement. Here, we explored the effects of secretome or conditioned medium (CM) derived from human embryonic stem cell‐derived MSCs (hESC‐MSCs) on hippocampal neurogenesis, inflammation, and apoptosis in experimental stroke.

Methods

Ischemic stroke was induced by right middle cerebral artery occlusion (MCAO) in male Wistar rats, and CM was infused either one time (1‐h post‐stroke; CM1) or three times (1‐, 24‐, and 48‐h post‐stroke; CM3) into left lateral ventricle. Neurogenesis markers (Nestin, Ki67, Doublecortin, and Reelin) were assessed at transcript and protein levels in the dentate gyrus of the hippocampus on day seven following MCAO. In parallel, changes in the gene expression of markers of apoptosis (Bax and Bim, as well as an anti‐apoptotic marker of Bcl2), inflammation (IL‐1β and IL‐6, as well as IL‐10 as an anti‐inflammatory cytokine), trophic factors (BDNF, GDNF, NGF, and NT‐3), and angiogenesis (CD31 and VEGF) in the hippocampus were assessed.

Results

Our results demonstrate that CM3 treatment could stimulate neurogenesis and angiogenesis concomitant with inhibition of inflammation, apoptosis, and neuronal loss in ischemic brains. Furthermore, rats treated with CM3 exhibited upregulation in neurotrophic factors.

Conclusion

Our results suggest that hESC‐MSC‐CM could promote neurogenesis and protect brain tissue from ischemic injury, partly mediated by induction of angiogenesis and neurotrophic factors and inhibition of inflammatory and apoptotic factors expression.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Pre-Conditioning with IFN-γ and Hypoxia Enhances the Angiogenic Potential of iPSC-Derived MSC Secretome

Induced pluripotent stem cell (iPSC) derived mesenchymal stem cells (iMSCs) represent a promising source of progenitor cells for approaches in the field of bone regeneration. Bone formation is a multi-step process in which osteogenesis and angiogenesis are both involved. Many reports show that the secretome of mesenchymal stromal stem cells (MSCs) influences the microenvironment upon injury, promoting cytoprotection, angiogenesis, and tissue repair of the damaged area. However, the effects of iPSC-derived MSCs secretome on angiogenesis have seldom been investigated. In the present study, the angiogenic properties of IFN-γ pre-conditioned iMSC secretomes were analyzed. We detected a higher expression of the pro-angiogenic genes and proteins of iMSCs and their secretome under IFN-γ and hypoxic stimulation (IFN-H). Tube formation and wound healing assays revealed a higher angiogenic potential of HUVECs in the presence of IFN-γ conditioned iMSC secretome. Sprouting assays demonstrated that within Coll/HA scaffolds, HUVECs spheroids formed significantly more and longer sprouts in the presence of IFN-γ conditioned iMSC secretome. Through gene expression analyses, pro-angiogenic genes (FLT-1, KDR, MET, TIMP-1, HIF-1α, IL-8, and VCAM-1) in HUVECs showed a significant up-regulation and down-regulation of two anti-angiogenic genes (TIMP-4 and IGFBP-1) compared to the data obtained in the other groups. Our results demonstrate that the iMSC secretome, pre-conditioned under inflammatory and hypoxic conditions, induced the highest angiogenic properties of HUVECs. We conclude that pre-activated iMSCs enhance their efficacy and represent a suitable cell source for collagen/hydroxyapatite with angiogenic properties.

Exploring the Role of Stem Cell Therapy in Treating Neurodegenerative Diseases: Challenges and Current Perspectives

:

Several human neurological disorders, such as Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis, Huntington’s disease, spinal cord injury, multiple sclerosis, and brain stroke, are caused by the injury to neurons or glial cells. The recent years have witnessed the successful generation of neurons and glia cells driving efforts to develop stem-cell-based therapies for patients to combat a broad spectrum of human neurological diseases. The inadequacy of suitable cell types for cell replacement therapy in patients suffering from neurological disorders has hampered the development of this promising therapeutic approach. Attempts are thus being made to reconstruct viable neurons and glial cells from different stem cells, such as embryonic stem cells, mesenchymal stem cells, and neural stem cells. Dedicated research to cultivate stem cell-based brain transplantation therapies has been carried out. We aim at compiling the breakthroughs in the field of stem cell-based therapy for the treatment of neurodegenerative maladies, emphasizing the shortcomings faced, victories achieved, and the future prospects of the therapy in clinical settings.

Human olfactory mesenchymal stromal cell transplantation ameliorates experimental autoimmune encephalomyelitis revealing an inhibitory role for IL16 on myelination

One of the therapeutic approaches for the treatment of the autoimmune demyelinating disease, multiple sclerosis (MS) is bone marrow mesenchymal stromal cell (hBM-MSCs) transplantation. However, given their capacity to enhance myelination in vitro, we hypothesised that human olfactory mucosa-derived MSCs (hOM-MSCs) may possess additional properties suitable for CNS repair. Herein, we have examined the efficacy of hOM-MSCs versus hBM-MSCs using the experimental autoimmune encephalomyelitis (EAE) model. Both MSC types ameliorated disease, if delivered during the initial onset of symptomatic disease. Yet, only hOM-MSCs improved disease outcome if administered during established disease when animals had severe neurological deficits. Histological analysis of spinal cord lesions revealed hOM-MSC transplantation reduced blood–brain barrier disruption and inflammatory cell recruitment and enhanced axonal survival. At early time points post-hOM-MSC treatment, animals had reduced levels of circulating IL-16, which was reflected in both the ability of immune cells to secrete IL-16 and the level of IL-16 in spinal cord inflammatory lesions. Further in vitro investigation revealed an inhibitory role for IL-16 on oligodendrocyte differentiation and myelination. Moreover, the availability of bioactive IL-16 after demyelination was reduced in the presence of hOM-MSCs. Combined, our data suggests that human hOM-MSCs may have therapeutic benefit in the treatment of MS via an IL-16-mediated pathway, especially if administered during active demyelination and inflammation.

Application of mesenchymal stem cells derived from human pluripotent stem cells in regenerative medicine

Mesenchymal stem cells (MSCs) represent the most clinically used stem cells in regenerative medicine. However, due to the disadvantages with primary MSCs, such as limited cell proliferative capacity and rarity in the tissues leading to limited MSCs, gradual loss of differentiation during in vitro expansion reducing the efficacy of MSC application, and variation among donors increasing the uncertainty of MSC efficacy, the clinical application of MSCs has been greatly hampered. MSCs derived from human pluripotent stem cells (hPSC-MSCs) can circumvent these problems associated with primary MSCs. Due to the infinite self-renewal of hPSCs and their differentiation potential towards MSCs, hPSC-MSCs are emerging as an attractive alternative for regenerative medicine. This review summarizes the progress on derivation of MSCs from human pluripotent stem cells, disease modelling and drug screening using hPSC-MSCs, and various applications of hPSC-MSCs in regenerative medicine. In the end, the challenges and concerns with hPSC-MSC applications are also discussed.

Tracking of human embryonic stem cell-derived mesenchymal stem cells in premature ovarian failure model mice

Premature ovarian failure (POF) is defined by amenorrhea, hypoestrogenism, elevated gonadotropin levels, and infertility. Chemotherapeutic agents are the most gonadotoxic agents that lead to POF. Although some previous studies have presented that mesenchymal stem cells (MSCs) transplantation could rescue the ovary function of POF animal models through the paracrine pathway, these mechanisms require further investigation. However, mechanisms of embryonic stem cell-derived MSCs (ES-MSCs) therapeutic effects on POF animal models have not been fully investigated yet. This study aimed to evaluate the migration and distribution of ES-MSCs in a model of chemotherapy-induced POF. Female mice received intraperitoneal injections of cyclophosphamide (Cy) to induce POF. Then, MSCs were labeled with green fluorescent protein (GFP) in vitro and injected intravenously into POF mice, and the distribution of MSCs was dynamically monitored at 1 week after transplantation. We harvested the lungs, liver, spleen, ovaries, heart, and kidneys 1 week after transplantation. The sections of these tissues were observed under the fluorescent microscope. More than 70% MSCs were successfully labeled with GFP at 72 h after labeling. MSCs were uniformly distributed in multiple organs and tissues including lungs, liver, spleen, ovaries, heart, and kidneys of POF mice. In mice, at 1week after intravenous transplantation, GFP labeled ES-MSCs were observed in the lungs, liver, spleen, ovaries, heart, and kidneys of POF mice, and the number of GFP labeled ES-MSCs in lungs, ovaries, and heart were higher than that in the spleen, kidneys, and liver. Our results revealed intravenously implanted ES-MSCs could migrate into the various tissues in chemotherapy-induced damaged POF mice.

Magnetic Fe3 O4 @graphene oxide improves the therapeutic effects of embryonic stem cells on acute liver damage

OBJECTIVE

Acute liver failure is usually associated with inflammation and oxidation of hepatocytes and has high mortality and resource costs. Mesenchymal stem cell (MSCs) has occasionally been reported to have no beneficial effect due to poor transplantation and the survival of implanted cells. Recent studies showed that embryonic stem cell (ESC)-derived MSCs are an alternative for regenerative medicine. On the other hand, graphene-based nanostructures have proven useful in biomedicine. In this study, we investigated whether magnetic graphene oxide (MGO) improved the effects of ESC-MSC conditioned medium (CM) on protecting hepatocytes and stimulating the regeneration of damaged liver cells.

MATERIALS AND METHODS

To provide a rat model of acute liver failure, male rats were injected intraperitoneally with carbon tetrachloride (CCl4 ). The rats were randomly divided into six groups, namely control, sham, CCl4 , ESC-MSC-CM, MGO and ESC-MSC-CM + MGO. In the experimental groups, the rats received, depending on the group, 2 ml/kg body weight CCl4 and either ESC-MSC-CM with 5 × 106 MSCs or 300 μg/kg body weight MGO or both. Symptoms of acute liver failure appeared 4 days after the injection. All groups were compared and analysed both histologically and biochemically 4 days after the injection. Finally, the results of ESC-MSC-CM and MSC-CM were compared.

RESULTS

The results indicated that the use of MGO enhanced the effect of ESC-MSC-CM on reducing necrosis, inflammation, aspartate transaminase, alanine aminotransferase and alkaline phosphatase in the CCl4 -induced liver failure of the rat model. Also, the expression of vascular endothelial growth factor and matrix metalloproteinase-9 (MMP-9) was significantly upregulated after treatment with MGO. Also, the results showed that the ESC-MSC-CM has more efficient effective compared to MSC-CM.

CONCLUSION

Magnetic graphene oxide improved the hepatoprotective effects of ESC-MSC-CM on acute liver damage, probably by suppressing necrosis, apoptosis and inflammation of hepatocytes.

Human Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells Acquire Rejuvenation and Reduced Heterogeneity

Despite the uniform selection criteria for the isolation of human mesenchymal stem cells (MSCs), considerable heterogeneity exists which reflects the distinct tissue origins and differences between individuals with respect to their genetic background and age. This heterogeneity is manifested by the variabilities seen in the transcriptomes, proteomes, secretomes, and epigenomes of tissue-specific MSCs. Here, we review literature on different aspects of MSC heterogeneity including the role of epigenetics and the impact of MSC heterogeneity on therapies. We then combine this with a meta-analysis of transcriptome data from distinct MSC subpopulations derived from bone marrow, adipose tissue, cruciate, tonsil, kidney, umbilical cord, fetus, and induced pluripotent stem cells derived MSCs (iMSCs). Beyond that, we investigate transcriptome differences between tissue-specific MSCs and pluripotent stem cells. Our meta-analysis of numerous MSC-related data sets revealed markers and associated biological processes characterizing the heterogeneity and the common features of MSCs from various tissues. We found that this heterogeneity is mainly related to the origin of the MSCs and infer that microenvironment and epigenetics are key drivers. The epigenomes of MSCs alter with age and this has a profound impact on their differentiation capabilities. Epigenetic modifications of MSCs are propagated during cell divisions and manifest in differentiated cells, thus contributing to diseased or healthy phenotypes of the respective tissue. An approach used to reduce heterogeneity caused by age- and tissue-related epigenetic and microenvironmental patterns is the iMSC concept: iMSCs are MSCs generated from induced pluripotent stem cells (iPSCs). During iMSC generation epigenetic and chromatin remodeling result in a gene expression pattern associated with rejuvenation thus allowing to overcome age-related shortcomings (e.g., limited differentiation and proliferation capacity). The importance of the iMSC concept is underlined by multiple clinical trials. In conclusion, we propose the use of rejuvenated iMSCs to bypass tissue- and age-related heterogeneity which are associated with native MSCs.

Involvement of various chemokine/chemokine receptor axes in trafficking and oriented locomotion of mesenchymal stem cells in multiple sclerosis patients

Multiple sclerosis (MS) is a specific type of chronic immune-mediated disease in which the immune responses are almost run against the central nervous system (CNS). Despite intensive research, a known treatment for MS disease yet to be introduced. Thus, the development of novel and safe medications needs to be considered for the disease management. Application of mesenchymal stem cells (MSCs) as an emerging approach was recruited forthe treatment of MS. MSCs have several sources and they can be derived from the umbilical cord, adipose tissue, and bone marrow. Chemokines are low molecular weight proteins that their functional activities are achieved by binding to the cell surface G protein-coupled receptors (GPCRs). Chemokine and chemokine receptors are of the most important and effective molecules in MSC trafficking within the different tissues in hemostatic and non-hemostatic circumstances. Chemokine/chemokine receptor axes play a pivotal role in the recruitment and oriented trafficking of immune cells both towards and within the CNS and it appears that chemokine/chemokine receptor signaling may be the most important leading mechanisms in the pathogenesis of MS. In this article, we hypothesized that the chemokine/chemokine receptor axes network have crucial and efficacious impacts on behavior of the MSCs, nonetheless, the exact responsibility of these axes on the targeted tropism of MSCs to the CNS of MS patients yet remained to be fully elucidated. Therefore, we reviewed the ability of MSCs to migrate and home into the CNS of MS patients via expression of various chemokine receptors in response to chemokines expressed by cells of CNS tissue, to provide a great source of knowledge.

Mesenchymal stem cells as a treatment for multiple sclerosis: a focus on experimental animal studies

Multiple sclerosis (MS) is a progressive and debilitating neurological condition in which the immune system abnormally attacks the myelin sheath insulating the nerves. Mesenchymal stem cells (MSCs) are found in most adult tissues and play a significant systemic role in self-repair. MSCs have promising therapeutic effects in many diseases, such as autoimmune diseases, including MS. MSCs have been tested in MS animal models, such as experimental autoimmune encephalomyelitis. Other studies have combined other agents with MSCs, genetically modified MSCs, or used culture medium from MSCs. In this review, we will summarize these studies and compare the main factors in each study, such as the source of MSCs, the type of animal model, the route of injection, the number of injected cells, and the mechanism of action.

Pluripotent-derived Mesenchymal Stem/stromal Cells: an Overview of the Derivation Protocol Efficacies and the Differences Among the Derived Cells

Mesenchymal stem/stromal cells (MSCs) are remarkable tools for regenerative medicine. Therapeutic approaches using these cells can promote increased activity and viability in several cell types through diverse mechanisms such as paracrine and immunomodulatory activities, contributing substantially to tissue regeneration and functional recovery. However, biological samples of human MSCs, usually obtained from adult tissues, often exhibit variable behavior during in vitro culture, especially with respect to cell population heterogeneity, replicative senescence, and consequent loss of functionality. Accordingly, it is necessary to establish standard protocols to generate high-quality, stable cell cultures, for example, by using pluripotent stem cells (PSCs) in derivation protocols of MSC-like cells since PSCs maintain their characteristics consistently during culture. However, the available protocols seem to generate distinct populations of PSC-derivedMSCs (PSC-MSCs) with peculiar attributes, which do not always resemble bona fide primary MSCs. The present review addresses the developmental basis behind some of these derivation protocols, exposing the differences among them and discussing the functional properties of PSC-MSCs, shedding light on elements that may help determine standard characterizations and criteria to evaluate and define these cells.

Stem cells as a potential therapeutic option for treating neurodegenerative diseases

In future, neurodegenerative diseases will take over cancer's place and become the major cause of death in the world, especially in developed countries. Advancements in the medical field and its facilities have led to an increase in the old age population, and thus contributing to the increase in number of people suffering from neurodegenerative diseases. Economically it is of a great burden to society and the affected family. No current treatment aims to replace, protect, and regenerate lost neurons; instead, it alleviates the symptoms, extends the life span by a few months and creates severe side effects. Moreover, people who are affected are physically dependent for performing their basic activities, which makes their life miserable. There is an urgent need for therapy that could be able to overcome the deficits of conventional therapy for neurodegenerative diseases. Stem cells, the unspecialized cells with the properties of self-renewing and potency to differentiate into various cells types can become a potent therapeutic option for neurodegenerative diseases. Stem cells have been widely used in clinical trials to evaluate their potential in curing different types of ailments. In this review, we discuss the various types of stem cells and their potential use in the treatment of neurodegenerative disease based on published preclinical and clinical studies.

Enhancement of angiogenesis and neurogenesis by intracerebroventricular injection of secretome from human embryonic stem cell-derived mesenchymal stem cells in ischemic stroke model

It is well accepted that the success of mesenchymal stem cells (MSCs) therapy against experimental stroke is mainly due to cellular paracrine manners rather than to replace lost tissue per se. Given such "bystander" effects, cell-free therapeutics manifest as a promising approach in regenerative medicine. Here we aimed at evaluating the effect of conditioned medium (CM) derived from human embryonic MSCs (hESC-MSC) on the neurological deficit, neurogenesis, and angiogenesis in experimental stroke. Adult male Wistar rats subjected to middle cerebral artery occlusion (MCAO), were treated with intracerebroventricular CM either one time (1 h post MCAO) or three times (1, 24, and 48 h post MCAO). Motor performance was assessed by the cylinder test on days 3 and 7. Cerebral samples were obtained for infarct size and molecular analysis on day 7 post-injury. Neurogenesis was evaluated by probing Nestin, Ki67, DCX, and Reelin transcripts and protein levels in the striatum, cortex, subventricular zone, and corpus callosum. The mRNA and protein expression of CD31 were also assessed in the striatum and cortical region to estimate angiogenesis post MCAO. Our findings demonstrate that CM treatment could significantly ameliorate neurological deficits and infarct volume in MCAO rats. Furthermore, ischemic stroke was associated with higher levels of neurogenesis and angiogenesis markers. Following treatment with CM, these markers were further potentiated in the brain regions. This study suggests that the therapeutic benefits of CM obtained from hESC-MSCs at least partly are mediated through improved neurogenesis and angiogenesis to accelerate the recovery of cerebral ischemia insult.

Mesenchymal Stem Cell and MicroRNA Therapy of Musculoskeletal Diseases

The therapeutic effects of mesenchymal stem cells (MSCs) in musculoskeletal diseases (MSDs) have been verified in many human and animal studies. Although some tissues contain MSCs, the number of cells harvested from those tissues and rate of proliferation in vitro are not enough for continuous transplantation. In order to produce and maintain stable MSCs, many attempts are made to induce differentiation from pluripotent stem cells (iPSCs) into MSCs. In particular, it is also known that the paracrine action of stem cell-secreted factors could promote the regeneration and differentiation of target cells in damaged tissue. MicroRNAs (miRNAs), one of the secreted factors, are small non-coding RNAs that regulate the translation of a gene. It is known that miRNAs help communication between stem cells and their surrounding niches through exosomes to regulate the proliferation and differentiation of stem cells. While studies have so far been underway targeting therapeutic miRNAs of MSDs, studies on specific miRNAs secreted from MSCs are still minimal. Hence, our ultimate goal is to obtain sufficient amounts of exosomes from iPSC-MSCs and develop them into therapeutic agents, furthermore to select specific miRNAs and provide safe cell-free clinical setting as a cell-free status with purpose of delivering them to target cells. This review article focuses on stem cell therapy on MSDs, specific microRNAs regulating MSDs and updates on novel approaches.

Priming human adipose-derived mesenchymal stem cells for corneal surface regeneration

Limbal stem cells (LSC) maintain the transparency of the corneal epithelium. Chemical burns lead the loss of LSC inducing an up-regulation of pro-inflammatory and pro-angiogenic factors, triggering corneal neovascularization and blindness. Adipose tissue-derived mesenchymal stem cells (AT-MSC) have shown promise in animal models to treat LSC deficiency (LSCD), but there are not studies showing their efficacy when primed with different media before transplantation. We cultured AT-MSC with standard medium and media used to culture LSC for clinical application. We demonstrated that different media changed the AT-MSC paracrine secretion showing different paracrine effector functions in an in vivo model of chemical burn and in response to a novel in vitro model of corneal inflammation by alkali induction. Treatment of LSCD with AT-MSC changed the angiogenic and inflammatory cytokine profile of mice corneas. AT-MSC cultured with the medium that improved their cytokine secretion, enhanced the anti-angiogenic and anti-inflammatory profile of the treated corneas. Those corneas also presented better outcome in terms of corneal transparency, neovascularization and histologic reconstruction. Priming human AT-MSC with LSC specific medium can potentiate their ability to improve corneal wound healing, decrease neovascularization and inflammation modulating paracrine effector functions in an in vivo optimized rat model of LSCD.

Human Hemangioblast-Derived Mesenchymal Stem Cells Promote Islet Engraftment in a Minimal Islet Mass Transplantation Model in Mice

Islet transplantation can restore glycemic control in patients with type 1 diabetes. Using this procedure, the early stages of engraftment are often crucial to long-term islet function, and outcomes are not always successful. Numerous studies have shown that mesenchymal stem cells (MSCs) facilitate islet graft function. However, experimental data can be inconsistent due to variables associated with MSC generation (including donor characteristics and tissue source), thus, demonstrating the need for a well-characterized and uniform cell product before translation to the clinic. Unlike bone marrow- or adipose tissue-derived MSCs, human embryonic stem cell-derived-MSCs (hESC-MSCs) offer an unlimited source of stable and highly-characterized cells that are easily scalable. Here, we studied the effects of human hemangioblast-derived mesenchymal cells (HMCs), (i.e., MSCs differentiated from hESCs using a hemangioblast intermediate), on islet cell transplantation using a minimal islet mass model. The co-transplantation of the HMCs allowed a mass of islets that was insufficient to correct diabetes on its own to restore glycemic control in all recipients. Our in vitro studies help to elucidate the mechanisms including reduction of cytokine stress by which the HMCs support islet graft protection in vivo. Derivation, stability, and scalability of the HMC source may offer unique advantages for clinical applications, including fewer islets needed for successful islet transplantation.

Mesenchymal Stem Cells for Neurological Disorders

Neurological disorders are becoming a growing burden as society ages, and there is a compelling need to address this spiraling problem. Stem cell-based regenerative medicine is becoming an increasingly attractive approach to designing therapies for such disorders. The unique characteristics of mesenchymal stem cells (MSCs) make them among the most sought after cell sources. Researchers have extensively studied the modulatory properties of MSCs and their engineering, labeling, and delivery methods to the brain. The first part of this review provides an overview of studies on the application of MSCs to various neurological diseases, including stroke, traumatic brain injury, spinal cord injury, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, and other less frequently studied clinical entities. In the second part, stem cell delivery to the brain is focused. This fundamental but still understudied problem needs to be overcome to apply stem cells to brain diseases successfully. Here the value of cell engineering is also emphasized to facilitate MSC diapedesis, migration, and homing to brain areas affected by the disease to implement precision medicine paradigms into stem cell-based therapies.

Human ESC-derived MSCs enhance fat engraftment by promoting adipocyte reaggregation, secreting CCL2 and mobilizing macrophages

Mesenchymal stem cells (MSCs) derived from somatic tissues have been used to promote lipotransfer, a common practice in cosmetic surgery. However, the effect of lipotransfer varies, and the mechanism of action remains vague. To address these questions, we differentiated human embryonic stem cells, a stable and unlimited source, into MSCs (EMSCs). Then we subcutaneously transplanted human fat aspirates together with EMSCs or PBS as a control into the back of nude mice. Within 24 h of transplantation, EMSCs promoted aggregation and encapsulation of injected fat tissues. Afterward, all grafts gradually shrank. However, EMSC-containing grafts were larger, heavier and had fewer dark areas on the surface than the control grafts. Histologically, more live adipocytes, vascular cells, and macrophages and less fibrosis were observed in EMSC-containing grafts than in the controls. Some EMSCs differentiated into vascular cells and adipocytes in the EMSC-containing grafts. RNA sequencing revealed that human RNA was shown to decline rapidly, while mouse RNA increased in the grafts; further, human genes related to extracellular matrix remodeling, adipogenesis, and chemokine (including CCL2) signaling were expressed at higher levels in the EMSC-containing grafts than they were in the controls. CCL2 knockout reduced macrophage migration towards EMSCs in vitro and early macrophage recruitment to the grafts and the pro-engraftment effect of EMSCs in vivo. Treating mice with a macrophage inhibitor abolished the EMSC effects and converted the grafts to heavy masses of cell debris. Together, these data demonstrate that EMSCs promote fat engraftment via enhanced tissue reconstitution and encapsulation of implanted tissues, which was followed by increased angiogenesis and adipocyte survival and reduced fibrosis, in which stimulated CCL2 signaling and mobilized macrophages play pivotal roles.

Improved Isolation of Human Vascular Wall-Resident Mesenchymal Stem Cells

Niches for tissue-resident mesenchymal stem cells (MSCs) have been identified in many adult tissues. In particular, MSCs residing in the vascular stem cell niche came into focus: the so-called vascular wall-resident MSCs (VW-MSCs) were, based upon their anatomic location, (1) distributed throughout the adult organism, and (2) supposed to be the first line cells which could be addressed in response to a pathologic trigger acting on or in close vicinity to the vascular system. Like tissue-resident MSCs in general, VW-MSC contribute to organ integrity and harbor the capacity to suppress inflammation and promote repair during normal vessel homeostasis, although resident MSCs present in the healthy situation of an individual seems not to bear sufficient for protection or repair following injury. In contrast, injury affected MSCs could contribute to disease induction and progression. A detailed understanding of the molecular repertoire as well as of the signaling pathways controlling stem cell fate of VW-MSCs is prerequisite to understand how (1) endogenous VW-MSCs contribute to normal vessel homeostasis as well as diseases that include the vascular system, (2) a potential on-site manipulation of these cells directly within their endogenous niche could be used for therapeutically benefits, and (3) isolated and therapeutically applied VW-MSCs in terms of exogenous MSCs with superior repair capabilities might be logically more efficient to address vascular diseases than MSCs derived from other tissues. This chapter describes a straightforward protocol for the improved isolation of human VW-MSCs.

The conditioned medium of human embryonic stem cell-derived mesenchymal stem cells alleviates neurological deficits and improves synaptic recovery in experimental stroke

The transplantation of mesenchymal stem cells (MSCs) is of main approaches in regenerative therapy for stroke. Due to the potential tumorigenicity and low survival rate of transplanted cells, focuses have been shifted from cell replacement to their paracrine effects. Therefore, stem cell-conditioned medium (CM) therapy has emerged as an alternative candidate. Here, we investigated the effect of CM derived from human embryonic MSCs on experimental ischemic stroke. Wistar rats underwent ischemic stroke by the right middle cerebral artery occlusion (MCAO). CM was infused either one time (1 hr post-MCAO) or three times (1, 24, and 48 hr post-MCAO) through guide cannula into the left lateral ventricle. Neurological functions were evaluated using Bederson's test and modified Neurological Severity Score on Days 1, 3, and 7 following MCAO. Infarction volumes and cerebral edema were measured on Days 3 and 7. growth-associated protein-43, synaptophysin, cAMP response element-binding protein, and phosphorylated-cAMP response element-binding protein levels were also assessed in peri-ischemic cortical tissue on Day 7 postsurgery. Our results indicated that three times injections of CM could significantly reduce body weight loss, mortality rate, infarct volumes, cerebral edema, and improve neurological deficits in MCAO rats. Moreover, three injections of CM could restore decreased levels of synaptic markers in MCAO rats up to its normal levels observed in the sham group. Our data suggest that using the CM obtained from embryonic stem cells-MSCs could be a potent therapeutic approach to attenuate cerebral ischemia insults which may be partly mediated through modulation of synaptic plasticity.

Optimal Hypoxic Preconditioning of Human Embryonic Stem Cell-Derived Mesenchymal Stem Cells (hES-MSCs) and Their Characteristics

Background and Objectives

Hypoxia is frequently used to enhance stem cell function. However, the optimal level of hypoxia for growth and function of human embryonic stem cell-derived mesenchymal stem cells (hES-MSCs) is yet to be determined. The purpose of this study was to find the optimal level of hypoxia for hES-MSCs and characteristics of hES-MSCs cultured under these optimal hypoxic conditions.

Methods and Results

Cell viability and changes in the morphology of hES-MSCs were determined through cell proliferation and CCK-8 assay. The hES-MSCs were preconditioned under various hypoxic conditions (0.5∼5% O₂ and 24∼72 h). The expression of cytokines in each culture condition was compared using cytokine array analysis. The morphology of hES-MSCs did not change under various hypoxic culture conditions. hES-MSCs viability after 48 h incubation in 2% O₂ condition was higher than that in normoxic condition. HIF1α expression was increased up to six folds after 48 h of hypoxic preconditioning. HIF1α expression in hES-MSCs peaked after 48 h of incubation in 1% O₂ condition. The expressions of PDGF-BB, IGFBP-6, VEGF-A, and angiogenin were increased after hES-MSCs were incubated for 48 h in 2% O₂ condition.

Conclusions

The hES-MSCs viability and expressions of PDGF-BB, IGFBP-6, VEGF-A, and angiogenin increased after 48 h incubation in 2% O₂ condition.

Two-step generation of mesenchymal stem/stromal cells from human pluripotent stem cells with reinforced efficacy upon osteoarthritis rabbits by HA hydrogel

Background

Current studies have enlightened the rosy prospects of human pluripotent stem cell (hPSC)-derived mesenchymal stem/stromal cells (MSCs) in regenerative medicine. However, systematic investigation of their signatures and applications with alternative biomaterials in osteoarthritis (OA) remains indistinct.

Methods

Herein, we initially took advantage of a small molecule library-mediated programming strategy for hPSC-MSC induction. Then, with the aid of multifaceted analyses such as flow cytometry (FCM), chromosome karyocyte and cell vitality, wound healing and microtubule formation assay and coculturing with T lymphocytes, we systematically evaluated the characterizations of signatures in vitro and the in vivo efficacy of hPSC-MSCs and HA hydrogel composite on rabbit osteoarthritis model.

Results

We found the combination of LLY-507 and AZD5153 was sufficient for high-efficiency CD73⁺CD90⁺CD105⁺CD31⁻CD34⁻CD45⁻HLA-DR⁻ MSC induction from both hESCs and hiPSCs with stemness (POU5F1/SOX2/NANOG). The programmed hPSC-MSCs revealed conservative transcriptome variations and went through a heterogeneous intermediate-stage with mesenchymal-associated gene expression (NT5E, ENG, VIM and FN1) as well as displayed typical cytomorphology, immunophenotypes and normal karyotyping, multilineage differentiation potential, favorable cell vitality, proangiogenic and immunoregulatory properties in vitro. Meanwhile, the cell population exhibited preferable restorative and ameliorative function on OA rabbits with HA hydrogel in vivo.

Conclusions

Collectively, we established a rapid and convenient procedure for hPSC-MSC generation without redundant manipulations. The fundamental and clinical studies upon osteoarthritis (OA) treatment would benefit tremendously from the combination of the inexhaustible hPSC-MSCs and advantageous biomaterials.

Embryonic stem cell-derived mesenchymal stem cells promote colon epithelial integrity and regeneration by elevating circulating IGF-1 in colitis mice

Rationale: Mesenchymal stem cells (MSCs) show promising therapeutic potential in treating inflammatory bowel disease (IBD) due to their immunomodulatory and trophic functions. However, their efficacy is influenced by tissue origin, donator condition, isolation, and expansion methods. Here, we generated phenotypically uniform MSCs from human embryonic stem cells (T-MSCs) and explored the molecular mechanisms involved in promoting mucosal integrity and regeneration in colitis mice. Methods: T-MSCs were injected intravenously into mice with dextran sulfate sodium (DSS)-induced colitis, and the in vivo distribution and therapeutic efficacy were evaluated. We performed serum cytokine antibody microarrays to screen potentially effective proteins and examined the therapeutic effect of insulin-like growth factor-1 (IGF-1). Colon epithelial regeneration potential was evaluated, and RNA sequencing was employed to determine the underlying molecular mechanisms. Finally, in vitro IGF-1 stimulation was performed to assess its effect on cell functions and organoid growth. Results: Intravenous administration of T-MSCs alleviated colitis in both acute and chronic DSS mouse models. Labeled T-MSCs were mainly distributed in the lungs, liver, and spleen after systemic infusion. The antibody array analysis of serum cytokines indicated that the IGF-1 level was increased in the treatment group, and serum ELISA further confirmed its elevation in the regeneration stage. Intraperitoneal injection of IGF-1 receptor inhibitors abrogated the anti-inflammatory activity of T-MSCs. The colonic epithelium of the treatment group showed greater regenerative potency than the controls and the IGF1R-PI3K-AKT pathway was up-regulated. RNA sequencing showed that T-MSC treatment contributed to colonic cell integrity and promoted xenobiotic metabolism. In vitro IGF-1 stimulation promoted the growth and proliferation of colon cells and organoids. Conclusions: Intravenous infusion of T-MSCs alleviated colitis in mice by elevating the circulating IGF-1 level. Increased IGF-1 maintained the integrity of epithelial cells and contributed to their repair and regeneration. Our study has identified T- MSCs as a potential cell resource for IBD treatment.

Human embryonic stem cell-derived mesenchymal stem cells improved premature ovarian failure

BACKGROUND

Premature ovarian failure (POF) affects many adult women less than 40 years of age and leads to infertility. According to previous reports, various tissue-specific stem cells can restore ovarian function and folliculogenesis in mice with chemotherapy-induced POF. Human embryonic stem cells (ES) provide an alternative source for mesenchymal stem cells (MSCs) because of their similarities in phenotype and immunomodulatory and anti-inflammatory characteristics. Embryonic stem cell-derived mesenchymal stem cells (ES-MSCs) are attractive candidates for regenerative medicine because of their high proliferation and lack of barriers for harvesting tissue-specific MSCs. However, possible therapeutic effects and underlying mechanisms of transplanted ES-MSCs on cyclophosphamide and busulfan-induced mouse ovarian damage have not been evaluated.

AIM

To evaluate ES-MSCs vs bone marrow-derived mesenchymal stem cells (BM-MSCs) in restoring ovarian function in a mouse model of chemotherapy-induced premature ovarian failure.

METHODS

Female mice received intraperitoneal injections of different doses of cyclophosphamide and busulfan to induce POF. Either human ES-MSCs or BM-MSCs were transplanted into these mice. Ten days after the mice were injected with cyclophosphamide and busulfan and 4 wk after transplantation of the ES-MSCs and/or BM-MSCs, we evaluated body weight, estrous cyclicity, follicle-stimulating hormone and estradiol hormone concentrations and follicle count were used to evaluate the POF model and cell transplantation. Moreover, terminal deoxynucleotidyl transferase mediated 2-deoxyuridine 5-triphosphate nick end labeling, real-time PCR, Western blot analysis and immunohistochemistry and mating was used to evaluate cell transplantation. Enzyme-linked immunosorbent assay was used to analyze vascular endothelial growth factor, insulin-like growth factor 2 and hepatocyte growth factor levels in ES-MSC condition medium in order to investigate the mechanisms that underlie their function.

RESULTS

The human ES-MSCs significantly restored hormone secretion, survival rate and reproductive function in POF mice, which was similar to the results obtained with BM-MSCs. Gene expression analysis and the terminal deoxynucleotidyl transferase mediated 2-deoxyuridine 5-triphosphate nick end labeling assay results indicated that the ES-MSCs and/or BM-MSCs reduced apoptosis in the follicles. Notably, the transplanted mice generated new offspring. The results of different analyses showed increases in antiapoptotic and trophic proteins and genes.

CONCLUSION

These results suggested that transplantation of human ES-MSCs were similar to BM-MSCs in that they could restore the structure of the injured ovarian tissue and its function in chemotherapy-induced damaged POF mice and rescue fertility. The possible mechanisms of human ES-MSC were related to promotion of follicular development, ovarian secretion, fertility via a paracrine effect and ovarian cell survival.

Changes of immune parameters of T lymphocytes and macrophages in EAE mice after BM-MSCs transplantation

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory infiltration, demyelination and axonal injury. Mesenchymal stem cells (MSCs) are pluripotent which can not only differentiate into many types of cells, but also have immunomodulatory effects. We show here that the transplantation of bone marrow MSCs (BM-MSCs) prevents the development of experimental autoimmune encephalomyelitis (EAE), the most common animal model of MS. Furthermore, we demonstrate that the immunologic mechanism by which BM-MSC transplantation ameliorates EAE involves inhibiting the proliferation and activation of T cells, reducing the production of inflammatory cytokines, and regulating macrophage responses, especially the macrophage polarization. The findings broaden our understanding about the regulation of T cell and macrophage immune responses by MSC transplantation.

Extracellular vesicles derived from human ES-MSCs protect retinal ganglion cells and preserve retinal function in a rodent model of optic nerve injury

Background

Retinal and/or optic nerve injury is one of the leading causes of blindness due to retinal ganglion cell (RGC) degeneration. There have been extensive efforts to suppress this neurodegeneration. Various somatic tissue-derived mesenchymal stem cells (MSCs) demonstrated significant neuroprotective and axogenic effects on RGCs. An alternative source of MSCs could be human embryonic stem cells (ES-MSCs), which proliferate faster, express lower levels of inflammatory cytokines, and are capable of immune modulation. It has been demonstrated that MSCs secrete factors or extracellular vesicles that may heal the injury. However, possible therapeutic effects and underlying mechanism of human ES-MSC extracellular vesicles (EVs) on optic nerve injury have not been assessed.

Methods

EVs were isolated from human ES-MSCs. Then, ES-MSC EV was applied to an optic nerve crush (ONC) mouse model. Immunohistofluorescence, retro- and anterograde tracing of RGCs, Western blot, tauopathy in RGCs, and function assessments were performed during 2-month post-treatment to evaluate ONC improvement and underlying mechanism of human ES-MSC EV in in vivo.

Results

We found that the ES-MSC EV significantly improved Brn3a+ RGCs survival and retro- and anterograde tracing of RGCs, while preventing retinal nerve fiber layer (RNFL) degenerative thinning compared to the vehicle group. The EVs also significantly promoted GAP43+ axon counts in the optic nerve and improved cognitive visual behavior. Furthermore, cis p-tau, a central mediator of neurodegeneration in the injured RGCs, is detectable after the ONC at the early stages demonstrated tauopathy in RGCs. Notably, after EV treatment cis p-tau was downregulated.

Conclusions

Our findings propose that human ES-MSC EVs, as an off-the-shelf and cell-free product, may have profound clinical implications in treating injured RGCs and degenerative ocular disease. Moreover, the possible mechanisms of human ES-MSC EV are related to the rescue of tauopathy process of RGC degeneration.

Mesenchymal stem cells in experimental autoimmune encephalomyelitis model of multiple sclerosis: A systematic review and meta-analysis

BACKGROUND/AIMS

Mesenchymal stem cells (MSCs) transplantation has been considered a possible therapeutic method for Multiple Sclerosis (MS). However, no quantitative data synthesis of MSCs therapy for MS exists. We conducted a systematic review and meta-analysis to evaluate the effects of MSCs in experimental autoimmune encephalomyelitis (EAE) animal model of MS.

METHODS

We identified eligible studies published from January 1980 to January 2017 by searching four electronic databases (PubMed, MEDLINE, Embase and Web of Science). The outcome was the effects of MSCs on clinical performance evaluated by the EAE clinical score.

RESULTS

36 preclinical studies including 675 animals in MSCs treatment group, and 693 animals in control group were included in this meta-analysis. We found that MSCs transplantation significantly ameliorated the symptoms and delayed the disease progression (SMD = -1.25, 95% CI: -1.45 to -1.05, P < 0.001). However, no significant differences in effect sizes were unveiled relative to clinical score standard (P = 0.35), type of MSCs (P = 0.35), source of MSCs (P = 0.06), MSCs dose (P = 0.44), delivery methods (P = 0.31) and follow up period (P = 0.73).

CONCLUSIONS

The current study showed that MSCs transplantation could ameliorate clinical performance in EAE animal model of MS. These findings support the further studies translate MSCs to treat MS in humans.

Stem cell therapy of myocardial infarction: a promising opportunity in bioengineering

Myocardial infarction (MI) is a life-threatening disease resulting from irreversible death of cardiomyocytes (CMs) and weakening of the heart blood-pumping function. Stem cell-based therapies have been studied for MI treatment over the last two decades with promising outcome. In this review, we critically summarize the past work in this field to elucidate the advantages and disadvantages of treating MI using pluripotent stem cells (PSCs) including both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), adult stem cells, and cardiac progenitor cells. The main advantage of the latter is their cytokine production capability to modulate immune responses and control the progression of healing. However, human adult stem cells have very limited (if not 'no') capacity to differentiate into functional CMs in vitro or in vivo. In contrast, PSCs can be differentiated into functional CMs although the protocols for the cardiac differentiation of PSCs are mainly for adherent cells under 2D culture. Derivation of PSC-CMs in 3D, allowing for large-scale production of CMs via modulation of the Wnt/β-catenin signal pathway with defined chemicals and medium, may be desired for clinical translation. Furthermore, the technology of purification and maturation of the PSC-CMs may need further improvements to eliminate teratoma formation after in vivo implantation of the PSC-CMs for treating MI. In addition, in vitro derived PSC-CMs may have mechanical and electrical mismatch with the patient's cardiac tissue, which causes arrhythmia. This supports the use of PSC-derived cells committed to cardiac lineage without beating for implantation to treat MI. In this case, the PSC derived cells may utilize the mechanical, electrical, and chemical cues in the heart to further differentiate into mature/functional CMs in situ. Another major challenge facing stem cell therapy of MI is the low retention/survival of stem cells or their derivatives (e.g., PSC-CMs) in the heart for MI treatment after injection in vivo. This may be resolved by using biomaterials to engineer stem cells for reduced immunogenicity, immobilization of the cells in the heart, and increased integration with the host cardiac tissue. Biomaterials have also been applied in the derivation of CMs in vitro to increase the efficiency and maturation of differentiation. Collectively, a lot has been learned from the past failure of simply injecting intact stem cells or their derivatives in vivo for treating MI, and bioengineering stem cells with biomaterials is expected to be a valuable strategy for advancing stem cell therapy towards its widespread application for treating MI in the clinic.

Human iPSC-derived iMSCs improve bone regeneration in mini-pigs

Autologous bone marrow concentrate (BMC) and mesenchymal stem cells (MSCs) have beneficial effects on the healing of bone defects. To address the shortcomings associated with the use of primary MSCs, induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) have been proposed as an alternative. The aim of this study was to investigate the bone regeneration potential of human iMSCs combined with calcium phosphate granules (CPG) in critical-size defects in the proximal tibias of mini-pigs in the early phase of bone healing compared to that of a previously reported autograft treatment and treatment with a composite made of either a combination of autologous BMC and CPG or CPG alone. iMSCs were derived from iPSCs originating from human fetal foreskin fibroblasts (HFFs). They were able to differentiate into osteoblasts in vitro, express a plethora of bone morphogenic proteins (BMPs) and secrete paracrine signaling-associated cytokines such as PDGF-AA and osteopontin. Radiologically and histomorphometrically, HFF-iMSC + CPG transplantation resulted in significantly better osseous consolidation than the transplantation of CPG alone and produced no significantly different outcomes compared to the transplantation of autologous BMC + CPG after 6 weeks. The results of this translational study imply that iMSCs represent a valuable future treatment option for load-bearing bone defects in humans.

Transplantation of human ESC-derived mesenchymal stem cell spheroids ameliorates spontaneous osteoarthritis in rhesus macaques

It has been demonstrated that mesenchymal stem cells (MSCs) differentiated from human embryonic stem cells (hESCs), name EMSCs, can treat a variety of autoimmune and inflammatory diseases, with similar efficacies to those achieved with MSCs derived from somatic tissues such as bone marrow (BMSCs). The chance increases even higher for EMSCs, than somatic tissue derived MSCs​, to become a cell drug as the former can be produced in large scale from an unlimited hESC line with easier quality control and less biosafety concern. We have further demonstrated that both human ESCs and EMSCs, after aggregation to form spheroids, can tolerate hypoxic and ambient conditions (AC) for over 4 and 10 days, respectively, without loss of their viability and alteration of their functions. Based on these advantages, we decided to test whether EMSC spheroids, made in large quantity and delivered through a long-term distance at AC, can treat osteoarthritis spontaneously developed in rhesus macaques (M. mulatta) monkeys as well as the allogenic MSCs.

Methods: Xenogeneic AC-transported EMSC spheroids or allogenic BMSCs were injected into the articular cavity of both knees of the monkeys at 3 animals per group. Another two macaques were injected the same way with saline as controls.

Results: Both EMSCs and BMSCs groups showed significant amelioration indicated by the reduction of swelling joint size and amplification of keen flare angle post-treatment, compared to the control group. Examinations via X-ray and MRI also indicated the decrease of inflammation and osteophyma, and recovery of the synovium and cartilage in both treated groups. No sign of allergy or graft versus host disease was observed in the animals.

Conclusion: Our results demonstrate that human EMSC spheroids can prevent the osteoarthtitis progression and ameliorate osteoarthritis in the rhesus macaques as well as allogenic BMSCs, and this study shall help advance the clinical application of EMSCs.

Noninvasive application of mesenchymal stem cell spheres derived from hESC accelerates wound healing in a CXCL12-CXCR4 axis-dependent manner

Mesenchymal stem cells (MSC) derived from adult tissues effectively promote wound healing. However, MSC quality varies, and the quantity of MSC is limited, as MSC are acquired through donations. Moreover, the survival and functioning of dissociated MSC delivered to an inflammatory lesion are subject to challenges.

Methods: Here, spheres (EMSC_Sp) generated from human embryonic stem cell-derived MSC (EMSC) were directly dropped onto excised wounds in mice; the effects of EMSC_Sp were compared to those of dissociated EMSC (EMSC_Diss). Following transplantation, we measured the extent of wound closure, dissected the histological features of the wounds, determined transcriptomic changes in cells isolated from the treated and control wounds, and evaluated the molecular mechanism of the effects of EMSC.

Results: The application of EMSC_Sp onto murine dermal wounds substantially increased survival and efficacy of EMSC compared to the topical application of EMSC_Diss. RNA sequencing (RNA-Seq) of cells isolated from the wounds highlighted the involvement of CXCL12-CXCR4 signaling in the effects of EMSC_Sp, which was verified in EMSC via CXCL12 knockdown and in target cells (vascular endothelial cells, epithelial keratinocytes, and macrophages) via CXCR4 inhibition. Finally, we enhanced the biosafety of EMSC_Sp by engineering cells with an inducible suicide gene.

Conclusions: Together, these data suggest the topical application of EMSC_Sp as an unlimited, quality-assured, safe, and noninvasive therapy for wound healing and the CXCL12-CXCR4 axis as a key player in this treatment.

IFN-γ-tethered hydrogels enhance mesenchymal stem cell-based immunomodulation and promote tissue repair

Because of their immunomodulatory activities, human mesenchymal stem cells (hMSCs) are being explored to treat a variety of chronic conditions such as inflammatory bowel disorders and graft-vs-host disease. Treating hMSCs with IFN-γ prior to administration augments these immunomodulatory properties; however, this ex vivo treatment limits the broad applicability of this therapy due to technical and regulatory issues. In this study, we engineered an injectable synthetic hydrogel with tethered recombinant IFN-γ that activates encapsulated hMSCs to increase their immunomodulatory functions and avoids the need for ex vivo manipulation. Tethering IFN-γ to the hydrogel increases retention of IFN-γ within the biomaterial while preserving its biological activity. hMSCs encapsulated within hydrogels with tethered IFN-γ exhibited significant differences in cytokine secretion and showed a potent ability to halt activated T-cell proliferation and monocyte-derived dendritic cell differentiation compared to hMSCs that were pre-treated with IFN-γ and untreated hMSCs. Importantly, hMSCs encapsulated within hydrogels with tethered IFN-γ accelerated healing of colonic mucosal wounds in both immunocompromised and immunocompetent mice. This novel approach for licensing hMSCs with IFN-γ may enhance the clinical translation and efficacy of hMSC-based therapies.

Human ES-derived MSCs correct TNF-α-mediated alterations in a blood-brain barrier model

Background

Immune cell trafficking into the CNS is considered to contribute to pathogenesis in MS and its animal model, EAE. Disruption of the blood–brain barrier (BBB) is a hallmark of these pathologies and a potential target of therapeutics. Human embryonic stem cell-derived mesenchymal stem/stromal cells (hES-MSCs) have shown superior therapeutic efficacy, compared to bone marrow-derived MSCs, in reducing clinical symptoms and neuropathology of EAE. However, it has not yet been reported whether hES-MSCs inhibit and/or repair the BBB damage associated with neuroinflammation that accompanies EAE.

Methods

BMECs were cultured on Transwell inserts as a BBB model for all the experiments. Disruption of BBB models was induced by TNF-α, a pro-inflammatory cytokine that is a hallmark of acute and chronic neuroinflammation.

Results

Results indicated that hES-MSCs reversed the TNF-α-induced changes in tight junction proteins, permeability, transendothelial electrical resistance, and expression of adhesion molecules, especially when these cells were placed in direct contact with BMEC.

Conclusions

hES-MSCs and/or products derived from them could potentially serve as novel therapeutics to repair BBB disturbances in MS.

Electronic supplementary material

The online version of this article (10.1186/s12987-019-0138-5) contains supplementary material, which is available to authorized users.

Generation of mesenchymal stem-like cells for producing extracellular vesicles

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with therapeutic potential against autoimmune diseases, inflammation, ischemia, and metabolic disorders. Contrary to the previous conceptions, recent studies have revealed that the tissue repair and immunomodulatory functions of MSCs are largely attributed to their secretome, rather than their potential to differentiate into desired cell types. The composition of MSC secretome encompasses cytokines and growth factors, in addition to the cell-derived structures known as extracellular vesicles (EVs). EVs are membrane-enclosed nanoparticles that are capable of delivering biomolecules, and it is now believed that MSC-derived EVs are the major players that induce biological changes in the target tissues. Based on these EVs’ characteristics, the potential of EVs derived from MSC (MSC-EV) in terms of tissue regeneration and immune modulation has grown during the last decade. However, the use of MSCs for producing sufficient amount of EVs has not been satisfactory due to limitations in the cell growth and large variations among the donor cell types. In this regard, pluripotent stem cells (PSCs)-derived MSC-like cells, which can be robustly induced and expanded in vitro, have emerged as more accessible cell source that can overcome current limitations of using MSCs for EV production. In this review, we have highlighted the methods of generating MSC-like cells from PSCs and their therapeutic outcome in preclinical studies. Finally, we have also discussed future requirements for making this cell-free therapy clinically feasible.

Production of Mesenchymal Stem Cells Through Stem Cell Reprogramming

Mesenchymal stem cells (MSCs) possess a broad spectrum of therapeutic applications and have been used in clinical trials. MSCs are mainly retrieved from adult or fetal tissues. However, there are many obstacles with the use of tissue-derived MSCs, such as shortages of tissue sources, difficult and invasive retrieval methods, cell population heterogeneity, low purity, cell senescence, and loss of pluripotency and proliferative capacities over continuous passages. Therefore, other methods to obtain high-quality MSCs need to be developed to overcome the limitations of tissue-derived MSCs. Pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), are considered potent sources for the derivation of MSCs. PSC-derived MSCs (PSC-MSCs) may surpass tissue-derived MSCs in proliferation capacity, immunomodulatory activity, and in vivo therapeutic applications. In this review, we will discuss basic as well as recent protocols for the production of PSC-MSCs and their in vitro and in vivo therapeutic efficacies. A better understanding of the current advances in the production of PSC-MSCs will inspire scientists to devise more efficient differentiation methods that will be a breakthrough in the clinical application of PSC-MSCs.

Human iPSC-derived MSCs (iMSCs) from aged individuals acquire a rejuvenation signature

BACKGROUND

Primary mesenchymal stem cells (MSCs) are fraught with aging-related shortfalls. Human-induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) have been shown to be a useful clinically relevant source of MSCs that circumvent these aging-associated drawbacks. To date, the extent of the retention of aging-hallmarks in iMSCs differentiated from iPSCs derived from elderly donors remains unclear.

METHODS

Fetal femur-derived MSCs (fMSCs) and adult bone marrow MSCs (aMSCs) were isolated, corresponding iPSCs were generated, and iMSCs were differentiated from fMSC-iPSCs, from aMSC-iPSCs, and from human embryonic stem cells (ESCs) H1. In addition, typical MSC characterization such as cell surface marker expression, differentiation capacity, secretome profile, and trancriptome analysis were conducted for the three distinct iMSC preparations-fMSC-iMSCs, aMSC-iMSCs, and ESC-iMSCs. To verify these results, previously published data sets were used, and also, additional aMSCs and iMSCs were analyzed.

RESULTS

fMSCs and aMSCs both express the typical MSC cell surface markers and can be differentiated into osteogenic, adipogenic, and chondrogenic lineages in vitro. However, the transcriptome analysis revealed overlapping and distinct gene expression patterns and showed that fMSCs express more genes in common with ESCs than with aMSCs. fMSC-iMSCs, aMSC-iMSCs, and ESC-iMSCs met the criteria set out for MSCs. Dendrogram analyses confirmed that the transcriptomes of all iMSCs clustered together with the parental MSCs and separated from the MSC-iPSCs and ESCs. iMSCs irrespective of donor age and cell type acquired a rejuvenation-associated gene signature, specifically, the expression of INHBE, DNMT3B, POU5F1P1, CDKN1C, and GCNT2 which are also expressed in pluripotent stem cells (iPSCs and ESC) but not in the parental aMSCs. iMSCs expressed more genes in common with fMSCs than with aMSCs. Independent real-time PCR comparing aMSCs, fMSCs, and iMSCs confirmed the differential expression of the rejuvenation (COX7A, EZA2, and TMEM119) and aging (CXADR and IGSF3) signatures. Importantly, in terms of regenerative medicine, iMSCs acquired a secretome (e.g., angiogenin, DKK-1, IL-8, PDGF-AA, osteopontin, SERPINE1, and VEGF) similar to that of fMSCs and aMSCs, thus highlighting their ability to act via paracrine signaling.

CONCLUSIONS

iMSCs irrespective of donor age and cell source acquire a rejuvenation gene signature. The iMSC concept could allow circumventing the drawbacks associated with the use of adult MSCs und thus provide a promising tool for use in various clinical settings in the future.

Stem-Cell Therapy Advances in China

Stem-cell therapy is a promising method for treating patients with a wide range of diseases and injuries. Increasing government funding of scientific research has promoted rapid developments in stem-cell research in China, as evidenced by the substantial increase in the number and quality of publications in the past 5 years. Multiple high-quality studies have been performed in China that concern cell reprogramming, stem-cell homeostasis, gene modifications, and immunomodulation. The number of translation studies, including basic and preclinical investigations, has also increased. Around 100 stem-cell banks have been established in China, 10 stem-cell drugs are currently in the approval process, and >400 stem cell-based clinical trials are currently registered in China. With continued state funding, advanced biotechnical support, and the development of regulatory standards for the clinical application of stem cells, further innovations are expected that will lead to a boom in stem-cell therapies. This review highlights recent achievements in stem-cell research in China and discusses future prospects.