Mesenchymal Stem Cells Secretion Research Articles

A Novel Method to Repair Thin Endometrium and Restore Fertility Based on Menstruation-Derived Stem Cell.

Thin endometrium (TE), which mainly occurs as a result of severe damage to the endometrial basalis, is one of the prominent etiologies of menstrual abnormalities, infertility, and recurrent miscarriage in women. Previous studies have demonstrated that mesenchymal stem cells (MSCs) are considered ideal cells with multipotency for regenerative medicine and exhibit therapeutic effects on TE through their cellular secretions. However, there is limited research on strategies to enhance MSC secretion to improve their therapeutic efficacy. Herein, we isolated menstrual blood-derived mesenchymal stem cells (MenSCs) from menstruation and transformed them into decidualized stromal cells (DSCs), which are specialized cells with enhanced secretory functions. To assess the therapeutic potential of DSCs compared to MenSCs, we conducted a series of experiments in cells and animals. The results demonstrated that DSCs exhibited changes in morphology compared to MenSCs, with a decrease in cell proliferation but a significant improvement in secretion function. Furthermore, DSCs facilitated the restoration of endometrial thickness and increased the number of glands and blood vessel formation. Most importantly, the pregnancy rates in rats were effectively restored, bringing them closer to normal levels. These findings greatly contribute to our understanding of stem cell therapy for TE and strongly suggest that DSCs could hold significant promise as a potential treatment option for TE.

Integrin beta 3-overexpressing mesenchymal stromal cells display enhanced homing and can reduce atherosclerotic plaque.

Umbilical cord (UC) mesenchymal stem cell (MSC) transplantation is a potential therapeutic intervention for atherosclerotic vascular disease. Integrin beta 3 (ITGB3) promotes cell migration in several cell types. However, whether ITGB-modified MSCs can migrate to plaque sites in vivo and play an anti-atherosclerotic role remains unclear. To investigate whether ITGB3-overexpressing MSCs (MSCsITGB3) would exhibit improved homing efficacy in atherosclerosis. UC MSCs were isolated and expanded. Lentiviral vectors encoding ITGB3 or green fluorescent protein (GFP) as control were transfected into MSCs. Sixty male apolipoprotein E-/- mice were acquired from Beijing Vital River Lab Animal Technology Co., Ltd and fed with a high-fat diet (HFD) for 12 wk to induce the formation of atherosclerotic lesions. These HFD-fed mice were randomly separated into three clusters. GFP-labeled MSCs (MSCsGFP) or MSCsITGB3 were transplanted into the mice intravenously via the tail vein. Immunofluorescence staining, Oil red O staining, histological analyses, western blotting, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction were used for the analyses. ITGB3 modified MSCs successfully differentiated into the "osteocyte" and "adipocyte" phenotypes and were characterized by positive expression (> 91.3%) of CD29, CD73, and CD105 and negative expression (< 1.35%) of CD34 and Human Leukocyte Antigen-DR. In a transwell assay, MSCsITGB3 showed significantly faster migration than MSCsGFP. ITGB3 overexpression had no effects on MSC viability, differentiation, and secretion. Immunofluorescence staining revealed that ITGB3 overexpression substantially enhanced the homing of MSCs to plaque sites. Oil red O staining and histological analyses further confirmed the therapeutic effects of MSCsITGB3, significantly reducing the plaque area. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction revealed that MSCITGB3 transplantation considerably decreased the inflammatory response in pathological tissues by improving the dynamic equilibrium of pro- and anti-inflammatory cytokines. These results showed that ITGB3 overexpression enhanced the MSC homing ability, providing a potential approach for MSC delivery to plaque sites, thereby optimizing their therapeutic effects.

O-alg-THAM/gel hydrogels functionalized with engineered microspheres based on mesenchymal stem cell secretion recruit endogenous stem cells for cartilage repair

Lacking self-repair abilities, injuries to articular cartilage can lead to cartilage degeneration and ultimately result in osteoarthritis. Tissue engineering based on functional bioactive scaffolds are emerging as promising approaches for articular cartilage regeneration and repair. Although the use of cell-laden scaffolds prior to implantation can regenerate and repair cartilage lesions to some extent, these approaches are still restricted by limited cell sources, excessive costs, risks of disease transmission and complex manufacturing practices. Acellular approaches through the recruitment of endogenous cells offer great promise for in situ articular cartilage regeneration. In this study, we propose an endogenous stem cell recruitment strategy for cartilage repair. Based on an injectable, adhesive and self-healable o-alg-THAM/gel hydrogel system as scaffolds and a biophysio-enhanced bioactive microspheres engineered based on hBMSCs secretion during chondrogenic differentiation as bioactive supplement, the as proposed functional material effectively and specifically recruit endogenous stem cells for cartilage repair, providing new insights into in situ articular cartilage regeneration.

Tropoelastin-Pretreated Exosomes from Adipose-Derived Stem Cells Improve the Synthesis of Cartilage Matrix and Alleviate Osteoarthritis.

Mesenchymal stem cells (MSCs) have recently been widely used to treat osteoarthritis (OA). Our prior research shows that tropoelastin (TE) increases MSC activity and protects knee cartilage from OA-related degradation. The underlying mechanism might be that TE regulates the paracrine of MSCs. Exosomes (Exos), the paracrine secretion of MSCs, have been found to protect chondrocytes, reduce inflammation, and preserve the cartilage matrix. In this study, we used Exos derived from TE-pretreated adipose-derived stem cells (ADSCs) (TE-ExoADSCs) as an injection medium, and compared it with Exos derived from unpretreated ADSCs (ExoADSCs). We found that TE-ExoADSCs could effectively enhance the matrix synthesis of chondrocytes in vitro. Moreover, TE pretreatment increased the ability of ADSCs to secrete Exos. In addition, compared with ExoADSCs, TE-ExoADSCs exhibited therapeutic effects in the anterior cruciate ligament transection (ACLT)-induced OA model. Further, we observed that TE altered the microRNA expression in ExoADSCs and identified one differentially upregulated microRNA: miR-451-5p. In conclusion, TE-ExoADSCs helped maintain the chondrocyte phenotype in vitro, and promoted cartilage repair in vivo. These therapeutic effects might be related with the altered expression of miR-451-5p in the ExoADSCs. Thus, the intra-articular delivery of Exos derived from ADSCs with TE pretreatment could be a new approach to treat OA.

Mesenchymal Stem Cell-Derived Exosomes Modulate Angiogenesis in Gastric Cancer

Individualized gastric cancer (GC) treatment aims at providing targeted therapies that translate the latest research into improved management strategies. Extracellular vesicle microRNAs have been proposed as biomarkers for GC prognosis. Helicobacter pylori infection influences the therapeutic response to and the drivers of malignant changes in chronic gastritis. The successful use of transplanted mesenchymal stem cells (MSCs) for gastric ulcer healing has raised interest in studying their effects on tumor neovascularization and in potential antiangiogenic therapies that could use mesenchymal stem cell secretion into extracellular vesicles-such as exosomes-in GC cells. The use of MSCs isolated from bone marrow in order to achieve angiogenic modulation in the tumor microenvironment could exploit the inherent migration of MSCs into GC tissues. Bone marrow-derived MSCs naturally present in the stomach have been reported to carry a malignancy risk, but their effect in GC is still being researched. The pro- and antiangiogenic effects of MSCs derived from various sources complement their role in immune regulation and tissue regeneration and provide further understanding into the heterogeneous biology of GC, the aberrant morphology of tumor vasculature and the mechanisms of resistance to antiangiogenic drugs.

Controlling the Stem Cell Environment Via Conducting Polymer Hydrogels to Enhance Therapeutic Potential

AbstractStem cells are a promising treatment option for various neurological diseases such as stroke, spinal cord injury, and other neurodegenerative disorders. However, the ideal environment to optimize the therapeutic potential of the cells remains poorly understood. Stem cells in the native environment are influenced by a combination of mechanical, chemical, and electrical cues for proliferation and differentiation. Because of their controllable properties, conductive hydrogels are promising biomaterials to interact with stem cells. Herein, this work develops an interpenetrating conducting polymer hydrogel with tunable mechanical properties. The hydrogel serves as a platform to provide mechanical and electrical cues for interactions with mesenchymal stem cells (MSCs). This work optimizes the formulation of the hydrogel for maximum viability of MSCs and relatively higher cytoskeletal protein expression. The viability of cells is not affected due to electrical stimulation (ES). Further, ES alters the trophic factor secretion of MSCs, with significant increase in VEGF pathway genes—VEGFA and HSPB1. In addition, substrate stiffness of the hydrogel enhances the VEGFB secretion compared to control. Hence, the conducting polymer hydrogel system creates a tunable physical and electrical niche to enhance the therapeutic potential of stem cells for neurological injuries.

Mechanical stimulation on a microfluidic device to highly enhance small extracellular vesicle secretion of mesenchymal stem cells.

Small extracellular vesicles (sEVs) are recognized as promising detection biomarkers and attractive delivery vehicles, showing great potential in diagnosis and treatment of diseases. However, the applications of sEVs are usually restricted by their poor secretion amount from donor cells under routine cell culture conditions, which is especially true for mesenchymal stem cells (MSCs) due to their limited expansion and early senescence. Here, a microfluidic device is proposed for boosting sEV secretion from MSCs derived from human fetal bone marrow (BM-MSCs). As the cells rapidly pass through a microfluidic channel with a series of narrow squeezing ridges, mechanical stimulation permeabilizes the cell membrane, thus promoting them to secrete more sEVs into extracellular space. In this study, the microfluidic device demonstrates that mechanical-squeezing effect could increase the secretion amount of sEVs from the BM-MSCs by approximately 4-fold, while maintaining cellular growth state of the stem cells. Further, the secreted sEVs are efficiently taken up by immortalized human corneal epithelial cells and accelerate corneal epithelial wound healing in vitro, indicating that this technique wound not affect the functionality of sEVs and demonstrating the application potentials of this technique.

Comparison of Gelatin/Polylysine- and Silk Fibroin/SDF-1α-Coated Mesenchymal Stem Cell-Seeded Intracranial Stents.

Endothelialization of the aneurysmal neck is essential for aneurysm healing after endovascular treatment. Mesenchymal stem cell (MSC)-seeded stents can promote aneurysm repair. The biological effects of coated and uncoated nitinol intracranial stents seeded with MSCs on vascular cells and macrophage proliferation and inflammation are investigated. Two stent coatings that exert pro-aggregation effects on MSCs via different mechanisms are examined: gelatin/polylysine (G/PLL), which enhances cell adhesion, and silk fibroin/SDF-1α (SF/SDF-1α), which enhances chemotaxis. The aim is to explore the feasibility of MSC-seeded coated stents in the treatment of intracranial aneurysms. The G/PLL coating provides the highest cytocompatibility and blood compatibility substrate for MSCs and vascular cells and promotes cell adhesion and proliferation. Moreover, it enhances MSC secretion and regulation of vascular cell and macrophage proliferation and chemotaxis. Although the SF/SDF-1α coating promotes MSC secretion and vascular cell chemotaxis, it induces a greater degree of macrophage proliferation, chemotaxis, and secretion of pro-inflammatory factors. MSC-seeded stents coated with G/PLL may benefit stent surface endothelialization and reduce the inflammatory response after endovascular treatment of intracranial aneurysm. These effects may improve aneurysm healing and increase the cure rate.

The antioxidant trolox inhibits aging and enhances prostaglandin E-2 secretion in mesenchymal stem cells

Mesenchymal stem cells (MSCs) have been widely used in regenerative medicine and clinical therapy due to their capabilities of proliferation, differentiation, and immune regulation. However, during in vitro expansion, MSCs are prone to aging, which largely limits their application. Prostaglandin E-2 (PGE-2) is a key effector secreted by MSCs to exert immunomodulatory effects. By screening the compound library for PGE-2 secretion, the antioxidant trolox was verified as a stimulator of MSCs to secrete PGE-2. The effect of antioxidant trolox on biological characteristics of MSCS, including aging, proliferation, and gene expression, was examined. The results demonstrated that trolox can resist aging, promote proliferation, and enhance PGE-2 secretion of MSCs without affecting their surface marker expression. Furthermore, trolox treatment up-regulates miR-17-92 clusters in MSCs and may contribute to its anti-aging effects. Thus, trolox addition might be beneficial for MSCs expansion and their application.

Impact of xenogenic mesenchimal stem cells secretome on a humoral component of the immune system

Objective. To determine such parameters of humoral immunity as the number of antibody-forming cells and the titer of antibodies in the blood under the action of the whole fraction of the secretome of xenogenic mesenchymal stem cells in mice with a normal immune status and mice with secondary immunodeficiency caused by the hydrocortisone acetate. Methods. The following methods were used in the study: isolation of mesenchymal stem cells from the bone marrow of cattle; culturing of isolated cells and obtaining a conditioned medium containing exometabolites with subsequent purification; modeling of secondary immunodeficiency in mice; setting up a test on mice to determine the number of antibody-forming cells in the spleen and hemagglutinin titers in blood serum; statistical data analysis. Results. A study of the impact of the secretome of xenogenic mesenchymal stem cells (MSCs) on the humoral arm of immunity in mice with a normal immune status showed a significant increase in the antibody-forming cells count compared with the control by 3.4-8.8 times when administered intramuscularly and by 4.2-5.4 times when administered subcutaneously (at the same time, in the group of the reference drug, the increase was four times), as well as an increase in the titer of hemagglutinins concerning the control by 25-95% when administered intramuscularly and 32-52% when administered subcutaneously (the reference drug Thymalin was at the control level). With intramuscular administration, a clear relationship was observed between the concentration of MSC secretome and the biological effect (high significant positive correlation: ρ = 0.99, p ≤ 0.05 for calculating AFC; ρ = 0.97, p ≤ 0.05 for HA titer). Lethality in the group of animals what administered only hydrocortisone acetate (HCA, positive control) was 100%. The use of the mesenchymal stem cells secretome increased the survival of animals by 50% by stimulating the formation of the required number of antibody-forming cells and antibody titer, except for the subcutaneous route of administration (at the level of immunized control, animals with a normal immune status). The reference drug showed a result at a level significantly lower than the immunized control. The antibody titer with the subcutaneous route of administration of secretion of MSCs was significantly lower than the immunized control but significantly higher concerning the reference drug. Conclusion. The administration of the secretome of xenogenic mesenchymal stem cells stimulated the humoral arm of immunity as same in mice with normal immune status as in mice with secondary immunodeficiency. The data obtained supplement the information on the introduction of live mesenchymal stem cells. Live allogeneic MSCs have a suppressive effect on B cells, while xenogenic MSCs cause a response on themselves. The secretome of xenogenic MSCs does not contain surface immunogenic molecules that are carried by living cells, but nevertheless increases the activity of the humoral component of immunity. The mechanisms of this effect require further study.

Evaluation of Inhibitory Effect of Abatacept (CTLA4-ig) and Conditioned Medium of Mesenchymal Stem Cell in an Acetic Acid-induced Mouse Model of Acute Colitis.

An individual with a genetic predisposition to inflammatory bowel disease (IBD) can experience inflammatory responses leading to conditions such as Crohn's disease (CD) or Ulcerative colitis (UC). Currently, stem cell therapies, particularly those utilizing mesenchymal stem cells (MSCs), are gaining attention due to their immunomodulatory properties, as demonstrated in clinical trials. Consequently, we decided to investigate the effects of mesenchymal stem cells-conditioned medium (MSC-CM) and Abatacept in an experimental model of acute colitis. MSC-CM was extracted from female BALB/C mice and stored for future use. Acute colitis was induced in BALB/C mice through the intrarectal administration of 100 µL of 4% acetic acid. Following this procedure, CM and Abatacept were administered intraperitoneally. Throughout the study, various parameters were monitored, including changes in body weight, bleeding, stool consistency, disease activity index (DAI), mortality rate, as well as the weight and length of the colon. Histopathological analyses were also conducted, along with monitoring changes in the levels of IL-10 and IFN-γ. The data collected are presented as mean ± SD and were analyzed using One-Way ANOVA. According to the results of the study, CM with and without Abatacept significantly reduced weight loss and bleeding as well as improved fecal consistency and DAI. Macroscopic examination of the colon showed that after infusion, colon length was reduced and histopathological analysis showed a decrease in mucosal changes. The secretion of IL-10 was increased while theIFN-γlevel was reduced. Research indicates that the immunomodulatory properties of MSC secretion can have positive effects. We propose a combination therapy with MSC, which we believe could lead to improved outcomes in the treatment of acute colitis.

Evaluation of neurotrophic factor secreting mesenchymal stem cells in progressive multiple sclerosis

Background: Autologous mesenchymal stem cell neurotrophic factor–secreting cells (NurOwn®) have the potential to modify underlying disease mechanisms in progressive multiple sclerosis (PMS). Objective: This open-label phase II study was conducted to evaluate safety/efficacy of three intrathecal cell treatments. Methods: Eighteen participants with non-relapsing PMS were treated. The primary endpoint was safety. Secondary endpoints included: cerebrospinal fluid (CSF) biomarkers; timed 25-foot walk speed, nine-hole peg test (9-HPT), low-contrast letter acuity, symbol digit modalities test, and 12-item multiple sclerosis (MS) walking scale. Seventeen participants received all treatments. Results: No deaths/adverse events related to worsening of MS, clinical/magnetic resonance imaging (MRI) evidence of disease activation, and clinically significant changes in safety lab results were reported. Two participants developed symptoms of low back and leg pain, consistent with a diagnosis of arachnoiditis, occurring in one of three intrathecal treatments in both participants. Nineteen percent of treated participants achieved pre-specified ⩾ 25% improvements in timed 25-foot walk speed/nine-HPT at 28 weeks compared to baseline, along with consistent efficacy signals for pre-specified response criteria across other secondary efficacy outcomes. CSF neuroprotective factors increased, and inflammatory biomarkers decreased after treatment, consistent with the proposed mechanism of action. Conclusion: Based on these encouraging preliminary findings, further confirmation in a randomized study is warranted.

Cellular Therapy: The Hope for Covid-19.

Coronaviruses (CoVs) are a group of very diverse viruses that cause a broad spectrum of diseases from mild to severe enteric, respiratory, systemic diseases, and common cold or pneumonia among humans and animals. This virus is associated with Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS), and lung disease that lead to Acute Respiratory Distress Syndrome (ARDS). In December 2019, researchers identified a novel coronavirus type, called Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2), which was associated with symptoms of high fever, dry cough, headache, diarrhea, and reduction of White Blood Cells (WBC). Coronavirus-associated acute respiratory disease was named Coronavirus Disease 19 (COVID-19). No proven treatment has been discovered for COVID-19 so far, but researchers are trying to find the best effective way to treat this disease. Therefore, therapeutic strategies that facilitate the recovery of COVID-19 patients and reduce life-threatening complications are urgently needed now. Today, Mesenchymal Stem Cells (MSCs) and their secretion are utilized as one of the most applied tools to treat various diseases such as inflammation and cancer. MSC-derived vesicles are rich in various growth factors, cytokines, and interleukins that are produced and secreted under different physiological or pathological conditions. These vesicles were considered a suitable and effective tool in regeneration medicine because of their high power in repairing damaged tissues and modulating immune responses. Recently, evidence has shown MSC-derived vesicles through reduced expression of pro-inflammatory cytokines could improve damaged tissues in COVID-19 patients. In addition to MSCs and MSC-derived exosomes, Natural Killer (NK) cells, T cells, and platelet lysates were used against viral infection. In this review, we tried to provide an overview of MSC secretion and immune cells for COVID-19 therapy.

Secretions released from mesenchymal stem cells improve spermatogenesis restoration of cytotoxic treatment with busulfan in azoospermia mice.

This study aimed at the efficacy of sequential treatment of bone marrow-derived mesenchymal stem cell secretion for busulfan-treated azoospermia in mice. The conditioned media (CM) was obtained from bone marrow mesenchymal stem cells (MSCs) or 293 cells. Chemically induced azoospermia mice received 200μl MSC-CM or 293-CM twice a week intravenously for three consecutive weeks. The histological assessment of spermatogenic recovery quantifying the expression of meiosis-associated genes, and Sertoli cell barrier functional factors were assessed. The characteristics of TM4 cells (Sertoli cell line) after pre-incubation of MSC-CM in vitro were also obtained. The MSC-CM group had the most spermatogenic colonies among the three groups (p<.05), but no spermatids were seen. Expressions of the meiosis-associated genes Dazl, Vasa, Miwi, Stra8, CyclinA1, Pgk2 and Scp3 in MSC-CM testis were remarkably higher compared with 293-CM and busulfan groups respectively (p<.05). The levels of Sertoli cell barrier functional factors, for example ICAM-1 and N-cadherin, were significantly increased during MSC-CM treatment (p<.05). Moreover, pre-incubation of MSC-CM particularly accelerated the CD54 (ICAM-1) and CD44 expressions of TM4 cells and promoted cell inherent adhesion. MSC-CM treatment can significantly improve the short-term restoration of spermatogonial structures of chemically induced azoospermia related to facilitating Sertoli cell adhesion integrity.

Glycosaminoglycan content of a mineralized collagen scaffold promotes mesenchymal stem cell secretion of factors to modulate angiogenesis and monocyte differentiation

Effective design of biomaterials to aid regenerative repair of craniomaxillofacial (CMF) bone defects requires approaches that modulate the complex interplay between exogenously added progenitor cells and cells in the wound microenvironment, such as osteoblasts, osteoclasts, endothelial cells, and immune cells. We are exploring the role of the glycosaminoglycan (GAG) content in a class of mineralized collagen scaffolds recently shown to promote osteogenesis and healing of craniofacial bone defects. We previously showed that incorporating chondroitin-6-sulfate or heparin improved mineral deposition by seeded human mesenchymal stem cells (hMSCs). Here, we examine the effect of varying scaffold GAG content on hMSC behavior, and their ability to modulate osteoclastogenesis, vasculogenesis, and the immune response. We report the role of hMSC-conditioned media produced in scaffolds containing chondroitin-6-sulfate (CS6), chondroitin-4-sulfate (CS4), or heparin (Heparin) GAGs on endothelial tube formation and monocyte differentiation. Notably, endogenous production by hMSCs within Heparin scaffolds most significantly inhibits osteoclastogenesis via secreted osteoprotegerin (OPG), while the secretome generated by CS6 scaffolds reduced pro-inflammatory immune response and increased endothelial tube formation. All conditioned media down-regulated many pro- and anti-inflammatory cytokines, such as IL6, IL-1β, and CCL18 and CCL17 respectively. Together, these findings demonstrate that modifying mineralized collagen scaffold GAG content can both directly (hMSC activity) and indirectly (production of secreted factors) influence overall osteogenic potential and mineral biosynthesis as well as angiogenic potential and monocyte differentiation towards osteoclastic and macrophage lineages. Scaffold GAG content is therefore a powerful stimulus to modulate reciprocal signaling between multiple cell populations within the bone healing microenvironment.

LncRNA HAND2-AS1 suppressed the growth of triple negative breast cancer via reducing secretion of MSCs derived exosomal miR-106a-5p.

Background: Triple-negative breast cancer (TNBC) is a special type of breast cancer, its tumor cell metastasis rate is much higher than other types, and at the same time has a high rate of postoperative recurrence, which significantly threatens the health of women. Thus, it is urgent to explore a new treatment for TNBC.Results: MiR-106a-5p was up-regulated in TNBC tissues and cells, and was positively correlated with the tumor grade, which indicated poor prognosis in TNBC patients. Mesenchymal stem cells (MSCs) can transport miR-106a-5p into TNBC cells via exosomes. Functional analysis showed exo-miR-106a-5p secreted by MSCs promoted tumor progression in TNBC cells. Furthermore, lncRNA HAND2-AS1 inhibited miR-106a-5p levels, and HAND2-AS1 was decreased in TNBC tissues and cells. Besides, overexpression of HAND2-AS1 reduced the secretion of exo-miR-106a-5p secretion from MSCs, thus suppressed TNBC development.Conclusion: Our study revealed that HAND2-AS1 inhibited the growth of TNBC, which were mediated by the inhibitory effects of MSC-derived exosomal miR-106a-5p.

Demineralized bone matrix scaffold modified with mRNA derived from osteogenically pre-differentiated MSCs improves bone repair

Gene therapy based on mRNA provides a promising approach for bone regeneration. Quick mRNA translation and controlled protein production could be earned by implantation of mRNA-activated scaffold in bone remodeling region. Furthermore, the expression levels of osteogenic-related mRNA in the cytoplasm of osteogenically pre-differentiated mesenchymal stem cells (MSCs) were high and the expression levels were different at different stages of osteogenically differentiated MSCs. This study intended to investigate the effect of osteoinductive-mRNAs (Oi-mRNAs), derived from osteogenically pre-differentiated MSCs at various stages (Day 1 (Oi1-mRNA), Day 3 (Oi3-mRNA), Day 7 (Oi7-mRNA), Day 14 (Oi14-mRNA) and Day 21 (Oi21-mRNA), respectively), on the osteogenic differentiation of MSCs. Further, the Oi-mRNAs combined with cationic polymer polyethylenimine (PEI) were loaded onto demineralized bone matrix (DBM) scaffold (Oi-mRNA/DBM). The results revealed that the Oi1-mRNA, Oi3-mRNA and Oi21-mRNA had no obvious effect on the osteogenic differentiation of MSCs, while the Oi7-mRNA increased the expression of alkaline phosphatase (ALP) and the Oi14-mRNA significantly promoted the expression of osteocalcin (OC) and osteopontin (OPN), and calcium deposition. In addition, the Oi14-mRNA/DBM scaffold could significantly enhance extracellular matrix (ECM) secretion and new collagen formation of MSCs. After being implanted into rat critical-sized cranium defect model, the Oi14-mRNA/DBM scaffold could promote the infiltration of cells and repair of bone defect in vivo. The DBM scaffold loaded with mRNA encoding osteoinductive protein may provide a powerful tool for bone defect repair.

A brief review on potential application of mesenchymal stem cell and secretome in combating mortality and morbidity in COVID-19 patients

Coronavirus disease 2019 (COVID-19) caused by novel Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV2), is typically associated with severe respiratory distress and has claimed more than 525,000 lives already. The most fearful aspect is the unavailability of any concrete guidelines and treatment or protective strategies for reducing mortality or morbidity caused by this virus. Repurposing of drugs, antivirals, convalescent plasma and neutralizing antibodies are being considered for treatment but are still questionable in lieu of the conflicting data, study design and induction of secondary infections. Stem cell therapy has seen substantial advancements over the past decade for the treatment of various diseases including pulmonary disorders with severe complications similar to COVID-19. Recently, mesenchymal stem cells (MSCs) have received particular attention as a potential therapeutic modality for SARS-CoV2 infection due to their ability to inhibit cytokine storm, a hallmark of severe COVID-19. MSCs secretion of trophic factors and extracellular vesicles mediated intercellular signaling are considered as principal contributing factors for tissue recovery. Although, recent preliminary studies have established the safety and efficacy of these cells without any severe secondary complications in the treatment of SARS-CoV2 infection, the rational use of MSCs on a large scale would still require additional relevant clinical investigations and validation of postulated mechanisms of these cells. This review presents the current clinical findings and update on the potential use of stem cell therapy and its secretome in combating the symptoms associated with COVID-19.

Three-Dimensional Culture of Umbilical Cord Mesenchymal Stem Cells Effectively Promotes Platelet Recovery in Immune Thrombocytopenia.

Mesenchymal stem cells (MSCs) can effectively regulate immune cell functions and therefore are promising for the treatment of autoimmune disorders, such as immune thrombocytopenia (ITP). Recent research has shown that three-dimensional (3D) culture method have many advantages over conventional culture with respect to MSC secretion and immunogenicity. In this study, 2D and 3D cultured MSCs were used to evaluate cytokine secretion, extracellular matrix (ECM) gene expression, immune regulatory activity, and therapeutic effects in a mouse model of ITP. MSCs cultured on scaffolds had higher expression levels of immune regulatory genes, such as IDO1, HLA-G, and PTGS2, and greater inhibitory activity against lymphocyte activation that those of 2D-MSCs. In addition, 3D-MSCs exhibited higher ECM expression and greater protection against interferon-γ (IFN-γ)-induced apoptosis. In a mouse study, ITP was induced by guinea pig anti-mouse platelet serum injections. Based on enzyme-linked immunosorbent assays, serum levels of the suppressive cytokine interleukin (IL)-10 were higher and IFN-γ levels were lower after intravenous injection with 3D-MSCs and with 2D-MSCs. Additionally, 3D-MSCs improved the body weight, spleen index, and platelet index relative to those for 2D-MSCs. Bone marrow homing was also significantly enhanced in the 3D group. Therefore, the 3D culture of MSCs is an effective technique for the treatment of ITP.

Secretome of Hypoxic Endothelial Cells Stimulates Bone Marrow-Derived Mesenchymal Stem Cells to Enhance Alternative Activation of Macrophages.

We intended to explore the cellular interaction between mesenchymal stem cells (MSCs) and injured endothelial cells leading to macrophage alternative polarization in healing kidney ischemic reperfusion injury. In vivo, the amounts of recruited macrophages were significantly mitigated by MSCs in the injured tissues, especially in the group using hematopoietic cell E- and L-selectin ligand (HCELL)-positive MSCs. Compared to controls, MSCs also enhanced expression of CD206 and CD163, which was further enhanced by HCELL expression. In vitro, analysis of cytokines involving macrophage polarization showed IL-13 rather than IL-4 from MSCs agreed with expression of macrophage CD206 in the presence of hypoxic endothelial cells. Among them, HCELL-positive MSCs in contact with hypoxic endothelial cells produced the greatest response, which were reduced without HCELL or using a transwell to prevent cell contact. With blockade of the respective cytokine, downregulated MSCs secretion of IL-13 and CD206 expression were observed using inhibitors of IFN-γ and TNF-α, but not using those of TGF-β and NO. With IFN-γ and TNF-α, MSCs IL-13 secretion and CD206 expression were upregulated. In conclusion, hypoxia induces endothelial cells producing multiple cytokines. Among them, IFN-γ and TNF-α that stimulate MSCs to secrete IL-13 but not IL-4, leading to alternative polarization.