Activity Of Mesenchymal Stem Cells Research Articles

#3345 EFFECTS OF CONDITIONED MEDIUMS COLLECTED FROM 2D OR 3D CULTURED MSCS ON KIDNEY FUNCTIONS OF RATS WITH AUTOIMMUNE DIABETES INDUCED WITH STREPTOZOCIN

Abstract Background and Aims The main mechanism of therapeutic action of mesenchymal stem cells (MSCs) could be resulted from their secretome content rather than their direct differentiation into damaged cells [1, 2]. Preconditioning of MSCs with different strategies like culturing in 3 dimensional (3D) culture scaffolds could improve their therapeutic potential [1]. Based on our previous study [1] in which the concentrations of total protein and specifically VEGF and IL-4 in conditioned mediums (CMs) collected from MSCs cultured in 3D culture conditions were increased compared to one of 2D, the aim of this study is comparative analysis of effects of CMs obtained from MSCs incubated under 2D and 3D culture conditions on kidney functions of rats with autoimmune type I diabetes (aT1D) induced with streptozocin (STZ). Method Isolation and characterization of the umbilical cord MSCs and the following analysis of concentrations of total protein and paracrine factors in the 2D-CMs and 3D-CMs were performed as it was mentioned [1]. Sprague-Dawley rats were treated with 20 mg/kg STZ for 5 consecutive days to induce T1D and 12 doses of CMs were intraperitoneally introduced for 4 weeks in accordance with the timeline defined in Figure 1. Therapeutic effects of CMs were comparatively investigated by biochemical, physical, histopathological and immunohistochemical analysis. Results At the end of the 2nd week, urinary albumin/creatinine (u-Alb/Cr) ratio and creatinine removal rate (Crr) of diabetes were significantly aggravated compared to control group (p = 0,0001 and p = 0,13 respectively). At the end of the 7th week, u-Alb/Cr ratios of both treatment groups were significantly improved compared to one of diabetes group (p = 0,029 vs p = 0,002). There was no statistical difference among all groups for Crr values. In the post treatment period u-Alb/Cr ratio was exacerbated (p = 0,014) while Crr value was not changed compared to pre-treatment period (p = 0,713). There was no statistical change between the pre- and post-treatment values of u-Alb/Cr ratio and Crr for both treatment groups. Renal mass index of control group was lower than the ones of experimental groups, while weight percent change from pre- to post-treatment period of control group was statistically higher than the ones of experimental groups (p = 0,0001). However, there was no statistical difference for both parameters among the experimental groups (Figure 2). Histopathological evaluations showed that cortical tubular damage (CTD) was significantly ameliorated in only D+3D-CM group compared to diabetes group (p = 0,012), while there was no statistical change in glomerular fibrosis in both treatment groups (Figure 3.1 and 3.2 respectively). Immunohistochemical analysis indicated that nephrin expression was insignificantly increased in both treatment groups compared to diabetes group (Figure 3.3). Preliminary evaluation of thicknesses of glomerular basal membrane and pedicel with transmission electron microscopy (TEM) showed no clear difference among all the groups (Figure 4). Conclusion CM obtained from MSCs in 3D culture conditions could partially ameliorate kidney functions of aT1D by improving CTD and expression of nephrin which is crucial for the integrity of glomerular filtration barrier.

The influence of mesenchymal stem cells and its derivatives on the qualitative indicators of animal sperm before and after cryoponservation (review)

During sperm cryopxation, sperm damage occurs due to osmotic stress, which entails deviations into the DNA and deformation of the tail of a sperm. To minimize destructive changes in cells, antioxidants or cryoprotective media supplemented with nutrient components are used. Numerous studies have established that the use of mesenchymal stem cells and their secret increases the percentage of viable and mobile sperm. Also, many of the soluble secretory factors of mesenchymal stem cells can be in extracellular vesicles and act as mediators of many paracrine actions of mesenchymal stem cells. They play the role of vehicles to displace unwanted cellular proteins, but the data of different authors demonstrated their potential role in many biological processes, including contribution to cell regeneration, survival and change in the phenotype of reici cells. The attachment or internalization of microseusiculi in target cells causes a wide range of epigenetic and phenotypic changes in recipient cells, such as a change in the viability of recipient cells, their adhesive properties and sensitivity or resistance to certain environmental factors. Spermeatozoa using microseusicals can be considered as an effective biological approach to maintaining and improving the quality of sperm, in the future, it can improve their viability and progressive mobility after cryopenservation. The wide therapeutic effect of mesenchymal stem cells and biologically active substances secreted by them requires further research to include sperm freezing in the protocols in order to overcome existing restrictions related to their use, and to clarify the exact mechanisms of their action. Further experiments, in particular in vivo, are necessary to confirm the actual clinical effects of these chemicals on the fertilizing ability of a spermatozoa. Thus, in this review, the issue of conducted studies in the field of use of mesenchymal stem cells and the substances they secrete during cryoponservation of animal sperm was covered.

Mesenchymal stem cells: diversity

Mesenchymal stem cells (MSCs) are diverse in terms of plastic, secretory and immunophenotypic features, which is due to the peculiarities of their genetic landscape. MSCs like other body cells are the result of the implementation of genetic information. However, some cells at different stages of histogenesis leave it. Such resident cells in tissues are stem cells. They are in a state of plastic quiescence and their genome does not undergo changes that would lead to commitment / differentiation. Although, these cells show a certain activity, producing various biologically active factors. It is logical to assume that the cells emerging from the process of histogenesis at its various stages will have different genetic landscapes, immunophenotypes and secretory potentials. The activation of MSCs occurs under conditions of physiological or reparative regeneration. Moreover, on the second hand it is explosive. Under natural conditions, the activation of MSCs during damage leads to their differentiation into fibroblasts and the formation of a connective tissue scar. But such consequences of reparation often come into conflict with the goal of treatment, when the task is not the formation of a scar, but the restoration of the parenchyma of the organ and its function. Therefore, the effects that will be obtained when using MSCs will depend on their initial state and methods of management. Aim. To analyze literature data on mesenchymal stem cells that reflect their ability to differentiate and secrete regulatory factors, immunophenotypic features and genetic landscape that may underlie their diversity. Conclusions. To obtain the desired result from the use of MSCs in regenerative medicine many factors must be taken into account. But data in this area is still fragmentary and often ambiguous. In addition, even taking into account the known factors in their various combinations is a very difficult task in the management of MSC. Given the unconditional priority of genetic and molecular research of MSCs the empirical method of studying the plastic and physiological properties of MSCs remains relevant today. It can just not create the basis for the development of the latest treatment methods, but also determine the direction of research in genetic and molecular research.

Potent antitumor effects of the conditioned medium of bone marrow-derived mesenchymal stem cells via IGFBP-4.

Cell transfer therapy using mesenchymal stem cells (MSCs) has pronounced therapeutic potential, but concerns remain about immune rejection, emboli formation, and promotion of tumor progression. Because the mode of action of MSCs highly relies on their paracrine effects through secretion of bioactive molecules, cell-free therapy using the conditioned medium (CM) of MSCs is an attractive option. However, the effects of MSC-CM on tumor progression have not been fully elucidated. Herein, we addressed this issue and investigated the possible underlying molecular mechanisms. The CM of MSCs derived from human bone marrow greatly inhibited the in vitro growth of several human tumor cell lines and the in vivo growth of the SCCVII murine squamous cell carcinoma cell line with reduced neovascularization. Exosomes in the MSC-CM were only partially involved in the inhibitory effects. The CM contained a variety of cytokines including insulin-like growth factor binding proteins (IGFBPs). Among them, IGFBP-4 greatly inhibited the in vitro growth of these tumors and angiogenesis, and immunodepletion of IGFBP-4 from the CM significantly reversed these effects. Of note, the CM greatly reduced the phosphorylation of AKT, ERK, IGF-1 receptor beta, and p38 MAPK in a partly IGFBP4-dependent manner, possibly through its binding to IGF-1/2 and blocking the signaling. The CM depleted of IGFBP-4 also reversed the inhibitory effects on in vivo tumor growth and neovascularization. Thus, MSC-CM has potent inhibitory effects on tumor growth and neovascularization in an IGFBP4-dependent manner, suggesting that cell-free therapy using MSC-CM could be a safer promising alternative for even cancer patients.

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.

COMPARATIVE STUDY ON THE EFFECT OF COLLAGEN AND FIBRIN HYDROGELS OF VARYING STIFFNESS ON MESENCHYMAL STEM CELL PARACRINE ACTIONS

Mesenchymal stem cells (MSC) have potent immunomodulatory and regenerative effects via soluble factors. One approach to improve stem cell-based therapies is encapsulation of MSC in hydrogels based on natural proteins such as collagen and fibrin, which play critical roles in bone healing. In this work, we comparatively studied the influence of collagen and fibrin hydrogels of varying stiffness on the paracrine interactions established by MSC with macrophages and osteoblasts.Type I collagen and fibrin hydrogels in a similar stiffness range loaded with MSC from donants were prepared by modifying the protein concentration. Viability and morphology of MSC in hydrogels as well as cell migration rate from the matrices were determined. Paracrine actions of MSC in hydrogels were evaluated in co-cultures with human macrophages from healthy blood donors or with osteoblasts from bone explants of patients with osteonecrosis of the femoral head.Lower matrix stiffness resulted in higher MSC viability and migration. Cell migration rate from collagen hydrogels was higher than from fibrin matrices. The secretion of the immunomodulatory factors interleukin-6 (IL-6) and prostaglandin E2 (PGE2) by MSC in both collagen and fibrin hydrogels increased with increasing matrix stiffness. Tumor necrosis factor-α (TNF-α) secretion by macrophages cultured on collagen hydrogels was lower than on fibrin matrices. Interestingly, higher collagen matrix stiffness resulted in lower secreted TNF-α while the trend was opposite on fibrin hydrogels. In all cases, TNF-α levels were lower when macrophages were cultured on hydrogels containing MSC than on empty gels, an effect partially mediated by PGE2. Finally, mineralization capacity of osteoblasts co-cultured with MSC in hydrogels increased with increasing matrix stiffness, although this effect was more notably for collagen hydrogels.Paracrine interactions established by MSC in hydrogels with macrophages and osteoblasts are regulated by matrix composition and stiffness.

Salmonella enhances osteogenic differentiation in adipose-derived mesenchymal stem cells.

The potential of mesenchymal stem cells (MSCs) for tissue repair and regeneration has garnered great attention. While MSCs are likely to interact with microbes at sites of tissue damage and inflammation, like in the gastrointestinal system, the consequences of pathogenic association on MSC activities have yet to be elucidated. This study investigated the effects of pathogenic interaction on MSC trilineage differentiation paths and mechanisms using model intracellular pathogen Salmonella enterica ssp enterica serotype Typhimurium. The examination of key markers of differentiation, apoptosis, and immunomodulation demonstrated that Salmonella altered osteogenic and chondrogenic differentiation pathways in human and goat adipose-derived MSCs. Anti-apoptotic and pro-proliferative responses were also significantly upregulated (p < 0.05) in MSCs during Salmonella challenge. These results together indicate that Salmonella, and potentially other pathogenic bacteria, can induce pathways that influence both apoptotic response and functional differentiation trajectories in MSCs, highlighting that microbes have a potentially significant role as influencers of MSC physiology and immune activity.

Light-emitting Diode Can Enhance the Metabolism and Paracrine Action of Mesenchymal Stem Cells.

This study investigated the influence of red light-emitting diodes (LED, 630 nm) on different irradiation parameters and the number of applications on mesenchymal stem cells derived from adipose tissue (AdMSCs) metabolism and paracrine factors. The AdMSCs were irradiated with a LEDbox device (output power: 2452.5 mW; laser beam: 163.5 cm2 ; irradiance: 15 mW cm-2 ) using radiant exposures of 0.5, 2, and 4 J cm-2 , respectively. AdMSCs were irradiated once or every 48 h up to three irradiations. All molecular analyses were performed 24 h after the last irradiation. LED did not induce changes in cell count, DNA damage, and oxidative stress. A significant repercussion of the LED has been noticed after three irradiations with 4 J cm-2 . AdMSCs had higher levels of IL-6, IGF-1, and NOx index. A higher ATP content and MMT/Resazurin assay were identified in AdMSCs irradiated three times with 4 J cm-2 . Mitochondrial basal respiration, maximal respiration and proton leak under metabolic stress were reduced by 0.5 and 2 J cm-2 irradiations. These data showed that three LED irradiations with 4 J cm-2 may be a suitable parameter for future AdMSCs therapy because of its improved metabolic activity, ATP content, and IL-6, IGF-1, and nitric oxide secretion.

MACF1 overexpression in BMSCs alleviates senile osteoporosis in mice through TCF4/miR-335-5p signaling pathway.

The decreased osteogenic differentiation ability of mesenchymal stem cells (MSCs) is one of the important reasons for SOP. Inhibition of Wnt signaling in MSCs is closely related to SOP. Microtubule actin crosslinking factor 1 (MACF1) is an important regulator in Wnt/β-catenin signal transduction. However, whether the specific expression of MACF1 in MSC regulates SOP and its mechanism remains unclear. We established MSC-specific Prrx1 (Prx1) promoter-driven MACF1 conditional knock-in (MACF-KI) mice, naturally aged male mice, and ovariectomized female mice models. Micro-CT, H&E staining, double calcein labeling, and the three-point bending test were used to explore the effects of MACF1 on bone formation and bone microstructure in the SOP mice model. Bioinformatics analysis, ChIP-PCR, qPCR, and ALP staining were used to explore the effects and mechanisms of MACF1 on MSCs' osteogenic differentiation. Microarray analysis revealed that the expression of MACF1 and positive regulators of the Wnt pathway (such as TCF4, β-catenin, Dvl) was decreased in human MSCs (hMSCs) isolated from aged osteoporotic than non-osteoporotic patients. The ALP activity and osteogenesis marker genes (Alp, Runx2, and Bglap) expression in mouse MSCs was downregulated during aging. Furthermore, Micro-CT analysis of the femur from 2-month-old MSC-specific Prrx1 (Prx1) promoter-driven MACF1 conditional knock-in (MACF-cKI) mice showed no significant trabecular bone changes compared to wild-type littermate controls, whereas 18- and 21-month-old MACF1 c-KI animals displayed increased bone mineral densities (BMD), improved bone microstructure, and increased maximum compression stress. In addition, the ovariectomy (OVX)-induced osteoporosis model of MACF1 c-KI mice had significantly higher trabecular volume and number, and increased bone formation rate than that in control mice. Mechanistically, ChIP-PCR showed that TCF4 could bind to the promoter region of the host gene miR-335-5p. Moreover, MACF1 could regulate the expression of miR-335-5p by TCF4 during the osteogenic differentiation of MSCs. These data indicate that MACF1 positively regulates MSCs osteogenesis and bone formation through the TCF4/miR-335-5p signaling pathway in SOP, suggesting that targeting MACF1 may be a novel therapeutic approach against SOP. MACF1, an important switch in the Wnt signaling pathway, can alleviate SOP through the TCF4/miR-335-5p signaling pathway in mice model. It might act as a therapeutic target for the treatment of SOP to improve bone function.

The potential role of exosome-derived mesenchymal stem cells and Balanites aegyptiaca in diabetic nephropathy amelioration in rats.

The utilization of mesenchymal stem cell (MSC)-derived exosomes, which include numerous growth factors, cytokines, and microRNAs, is the primary aspect of the novel MSC activity models. The current research aims to: (i) identify the morphology of exosomes; (ii) determine exosomes secreted into MSCs conditioned cell culture medium; and (iii) perform a comprehensive characterization of isolated exosomes and elucidate their protective role in the diabetic nephropathy animal model. Ultracentrifugation was performed by utilizing the culture supernatant of MSCs. Transmission electron microscopy, nanoparticle tracking analysis, as well as Western blot, were utilized for isolated exosome characterization. The purified exosomes were used for in vivo implantation in a diabetic nephropathy animal model. The present research was carried out on 70 adult male albino rats weighing 180 to 200 grams. Rats were classified into seven groups: Group I: negative control group; Group II: diabetic nephropathy group; Group III: Balanites therapeutic group; Group IV: Balanites + MSCs therapeutic group; Group V: Balanites + exosome therapeutic group; Group VI: MSCs therapeutic group; and Group VII: exosome therapeutic group. By the end of the study period, total antioxidant capacity (TAC), malondialdehyde (MDA), and the histology of pancreatic tissue were assessed. Isolated exosomes with sizes ranging from 30 to 150 nm demonstrated the typical cup-shaped morphology. Additionally, exosome criteria were demonstrated by the exosome surface proteins CD81 and CD63, which were expressed by exosome marker proteins. Treatment with exosomes along with Balanites induced a significant reduction in pancreatic MDA with a substantial elevation in pancreatic TAC. Furthermore, treatment with exosomes and Balanites demonstrated normal pancreatic parenchyma and pancreatic lobules with normal pancreatic acini and acinar cells. These findings strongly suggest that ultracentrifugation is the most efficient tool for isolating exosomes. Also, these findings demonstrated that Balanites and exosomes had synergistic effects on one another, with more potent renoprotective activities in rats.

Mesenchymal stem cells in ischemic tissue regeneration.

Diseases caused by ischemia are one of the leading causes of death in the world. Current therapies for treating acute myocardial infarction, ischemic stroke, and critical limb ischemia do not complete recovery. Regenerative therapies opens new therapeutic strategy in the treatment of ischemic disorders. Mesenchymal stem cells (MSCs) are the most promising option in the field of cell-based therapies, due to their secretory and immunomodulatory abilities, that contribute to ease inflammation and promote the regeneration of damaged tissues. This review presents the current knowledge of the mechanisms of action of MSCs and their therapeutic effects in the treatment of ischemic diseases, described on the basis of data from in vitro experiments and preclinical animal studies, and also summarize the effects of using these cells in clinical trial settings. Since the obtained therapeutic benefits are not always satisfactory, approaches aimed at enhancing the effect of MSCs in regenerative therapies are presented at the end.

Efficient Liposome Loading onto Surface of Mesenchymal Stem Cells via Electrostatic Interactions for Tumor-Targeted Drug Delivery.

Mesenchymal stem cells (MSCs) have a tumor-homing capacity; therefore, MSCs are a promising drug delivery carrier for cancer therapy. To maintain the viability and activity of MSCs, anti-cancer drugs are preferably loaded on the surface of MSCs, rather than directly introduced into MSCs. In this study, we attempted to load liposomes on the surface of MSCs by using the magnetic anionic liposome/atelocollagen complexes that we previously developed and assessed the characters of liposome-loaded MSCs as drug carriers. We observed that large-sized magnetic anionic liposome/atelocollagen complexes were abundantly associated with MSCs via electrostatic interactions under a magnetic field, and its cellular internalization was lower than that of the small-sized complexes. Moreover, the complexes with higher atelocollagen concentrations showed lower cellular internalization than the complexes with lower atelocollagen concentrations. Based on these results, we succeeded in the efficient loading of liposomes on the surface of MSCs by using large-sized magnetic anionic liposomes complexed with a high concentration of atelocollagen. The constructed liposome-loaded MSCs showed a comparable proliferation rate and differentiation potential to non-loaded MSCs. Furthermore, the liposome-loaded MSCs efficiently adhered to vascular endothelial cells and migrated toward the conditioned medium from cancer cells in vitro and solid tumor tissue in vivo. These findings suggest that liposome-loaded MSCs could serve as an efficient cell-based drug carrier for tumor-targeted delivery.

Alterations of mesenchymal stem cells on regulating Th17 and Treg differentiation in severe aplastic anemia.

Immune-mediated hematopoietic destruction is a key factor in idiopathic severe aplastic anemia (SAA). With great immunomodulatory functions, mesenchymal stem cells (MSCs) are important for bone marrow niche. While the underlying etiology of immunologic changes in SAA bone marrow remains unknown, dysfunctional MSCs are implicated as a major cause. To provide evidence for their defects in immunomodulation, alterations of SAA MSCs in regulating T cell differentiation were determined. During differentiation from CD4+ T cells into T helper 17 (Th17) cells under polarization conditions, impaired inhibition on IL-17 and IL-1β production was noted when cocultured with SAA MSCs compared to control MSCs (P < 0.05). After stimulation of Th17 activation, the percentage of IL-17-secreting cells was significantly increased in the SAA group (9.1 ± 1.5% vs 6.6 ± 0.4%, P < 0.01). Under regulatory T (Treg) polarization, a higher percentage of CD4+CD25+FoxP3+ Treg cells was detected when cocultured with SAA MSCs compared to control MSCs (8.1 ± 0.5% vs 5.8 ± 0.8%, P < 0.01). Inconsistently, transforming growth factor-β (TGF-β) concentrations in the culture supernatant were decreased and IL-1β concentrations were elevated in the SAA group. Our data indicated impaired inhibition of SAA MSCs on Th17 activation and aberrant regulation of SAA MSCs on Treg differentiation. Increased IL-17 and IL-1β levels with decreased TGF-β levels in the supernatant suggested the potential of SAA MSCs for triggering a hyperinflammatory environment. Dysfunctional MSCs could contribute to the lack of immunoprotection in the bone marrow, which may be associated with SAA.

Extracellular Vesicle-Loaded Oncogenic lncRNA NEAT1 from Adipose-Derived Mesenchymal Stem Cells Confers Gemcitabine Resistance in Pancreatic Cancer via miR-491-5p/Snail/SOCS3 Axis.

It is becoming increasingly evident that key mechanisms of mesenchymal stem cell (MSC) efficacy appear to associate with paracrine activities, and the delivery of cargos through extracellular vesicles (EVs) controls the mechanistic actions of MSCs. Thus, this study clarified a possible mechanism by which EV-encapsulated NEAT1 from adipose-derived mesenchymal stem cells (ADSCs) might mediate gemcitabine resistance in pancreatic cancer (PCa). Microarray profile suggested a differentially expressed lncRNA NEAT1 in PCa, and we determined its expression in PCa cells. NEAT1 was found to be upregulated in PCa. The binding affinity among NEAT1, miR-491-5p, and Snail was identified through bioinformatic analysis and experimental validation. NEAT1 competitively bound to miR-491-5p to elevate Snail expression and diminish SOCS3 expression. PCa cells were cocultured with EVs extracted from ADSCs, followed by assessment of malignant phenotypes, tumorigenesis, and gemcitabine resistance of PCa cells using gain- or loss-of-function experiments. ADSC-derived EVs carrying NEAT1 promoted PCa cell proliferation, migration, and gemcitabine resistance in vitro and enhanced tumorigenicity in vivo by inhibiting miR-491-5p and SOCS3 and upregulating Snail. Collectively, the findings from our study found a new potential strategy for gemcitabine resistance in PCa by illustrating the mechanistic insights of oncogenic ADSC-derived EVs-loaded NEAT1 via regulating the miR-491-5p/Snail/SOCS3 axis.

Modulatory effects of mesenchymal stem cells on microglia in ischemic stroke.

Ischemic stroke accounts for 70-80% of all stroke cases. Immunity plays an important role in the pathophysiology of ischemic stroke. Microglia are the first line of defense in the central nervous system. Microglial functions are largely dependent on their pro-inflammatory (M1-like) or anti-inflammatory (M2-like) phenotype. Modulating neuroinflammation via targeting microglia polarization toward anti-inflammatory phenotype might be a novel treatment for ischemic stroke. Mesenchymal stem cells (MSC) and MSC-derived extracellular vesicles (MSC-EVs) have been demonstrated to modulate microglia activation and phenotype polarization. In this review, we summarize the physiological characteristics and functions of microglia in the healthy brain, the activation and polarization of microglia in stroke brain, the effects of MSC/MSC-EVs on the activation of MSC in vitro and in vivo, and possible underlying mechanisms, providing evidence for a possible novel therapeutics for the treatment of ischemic stroke.

Mesenchymal stem cells limit vascular and epithelial damage and restore the impermeability of the urothelium in chronic radiation cystitis

BackgroundCellular therapy seems to be an innovative therapeutic alternative for which mesenchymal stem cells (MSCs) have been shown to be effective for interstitial and hemorrhagic cystitis. However, the action of MSCs on chronic radiation cystitis (CRC) remains to be demonstrated. The aim of this study was to set up a rat model of CRC and to evaluate the efficacy of MSCs and their mode of action.MethodsCRC was induced by single-dose localized irradiation of the whole bladder using two beams guided by tomography in female Sprague–Dawley rat. A dose range of 20–80 Gy with follow-up 3–12 months after irradiation was used to characterize the dose effect and the kinetics of radiation cystitis in rats. For the treatment, the dose of 40 Gy was retained, and in order to potentiate the effect of the MSCs, MSCs were isolated from adipose tissue. After expansion, they were injected intravenously during the pre-chronic phase. Three injections of 5 million MSCs were administered every fortnight. Follow-up was performed for 12 months after irradiation.ResultsWe observed that the intensity and frequency of hematuria are proportional to the irradiation dose, with a threshold at 40 Gy and the appearance of bleeding from 100 days post-irradiation. The MSCs reduced vascular damage as well as damage to the bladder epithelium.ConclusionsThese results are in favor of MSCs acting to limit progression of the chronic phase of radiation cystitis. MSC treatment may afford real hope for all patients suffering from chronic radiation cystitis resistant to conventional treatments.

Mechanisms of Action of Mesenchymal Stem Cells in Metabolic-Associated Fatty Liver Disease.

Metabolic-associated fatty liver disease (MAFLD) is currently the most common chronic liver disease worldwide. However, its pathophysiological mechanism is complicated, and currently, it has no FDA-approved pharmacological therapies. In recent years, mesenchymal stem cell (MSC) therapy has attracted increasing attention in the treatment of hepatic diseases. MSCs are multipotent stromal cells that originated from mesoderm mesenchyme, which have self-renewal and multipotent differentiation capability. Recent experiments and studies have found that MSCs have the latent capacity to be used for MAFLD treatment. MSCs have the potential to differentiate into hepatocytes, which could be induced into hepatocyte-like cells (HLCs) with liver-specific morphology and function under appropriate conditions to promote liver tissue regeneration. They can also reduce liver tissue injury and reverse the development of MAFLD by regulating immune response, antifibrotic activities, and lipid metabolism. Moreover, several advantages are attributed to MSC-derived exosomes (MSC-exosomes), such as targeted delivery, reliable reparability, and poor immunogenicity. After entering the target cells, MSC-exosomes help regulate cell function and signal transduction; thus, it is expected to become an emerging treatment for MAFLD. In this review, we comprehensively discussed the roles of MSCs in MAFLD, main signaling pathways of MSCs that affect MAFLD, and mechanisms of MSC-exosomes on MAFLD.

Effective role of Curcumin on expression regulation of EZH2 histone methyltransferase as a dynamic epigenetic factor in osteogenic differentiation of human mesenchymal stem cells

BackgroundEfficient differentiation of mesenchymal stem cells (MSCs) into a desired cell lineage remains challenging in cell-based therapy and regenerative medicine. Numerous efforts have been made to efficiently promote differentiation of MSCs into osteoblast lineage. Accordingly, epigenetic signatures emerge as a key conductor of cell differentiation. Among them, Enhancer of Zeste Homolog 2 (EZH2), a histone methyltransferase appears to suppress osteogenesis. Curcumin is an osteoinductive natural polyphenol compound which supposedly modulates epigenetic mechanisms. Hence, the current study aims to address the role of the EZH2 epigenetic factor in osteogenic activity of MSCs after Curcumin treatment. MethodsThe effect of Curcumin on viability and osteogenic differentiation was evaluated at different time points in vitro. The expression level of EZH2 was assessed using quantitative real-time polymerase chain reaction (qRT-PCR) after 14 and 21 days. ResultsMTT results showed no cytotoxic effects at concentrations of 10 and 15 μM of Curcumin and cells survived up to 70 % at all time-points. qRT-PCR results demonstrated that Curcumin significantly enhanced the expression levels of osteogenic markers that included Runx2, Osterix, Collagen type I, Osteopontin and Osteocalcin at day 21. ConclusionsInterestingly, we observed that the expression level of the EZH2 gene was downregulated in the presence of Curcumin compared to the control group during osteogenesis. This study confirmed that Curcumin acts as an epigenetic switch to regulate osteoblast differentiation specifically through the EZH2 suppression.

Can a Large Number of Transplanted Mesenchymal Stem Cells Have an Optimal Therapeutic Effect on Improving Ovarian Function?

Mesenchymal stem cells (MSCs) are next-generation treatment in degenerative diseases. For the application of mesenchymal stem cell therapy to degenerative disease, transplantation conditions (e.g., optimized dose, delivery route and regenerating efficacy) should be considered. Recently, researchers have studied the mode of action of MSC in the treatment of ovarian degenerative disease. However, the evidence for the optimal number of cells for the developing stem cell therapeutics is insufficient. The objective of this study was to evaluate the efficacy in ovarian dysfunction, depends on cell dose. By intraovarian transplantation of low (1 × 105) and high (5 × 105) doses of placenta-derived mesenchymal stem cells (PD-MSCs) into thioacetamide (TAA)-injured rats, we compared the levels of apoptosis and oxidative stress that depend on different cell doses. Apoptosis and oxidative stress were significantly decreased in the transplanted (Tx) group compared to the non-transplanted (NTx) group in ovarian tissues from TAA-injured rats (* p &lt; 0.05). In addition, we confirmed that follicular development was significantly increased in the Tx groups compared to the NTx group (* p &lt; 0.05). However, there were no significant differences in the apoptosis, antioxidant or follicular development of injured ovarian tissues between the low and high doses PD-MSCs group. These findings provide new insights into the understanding and evidence obtained from clinical trials for stem cell therapy in reproductive systems.

Intraarticular Injections of Mesenchymal Stem Cells in Knee Osteoarthritis: A Review of Their Current Molecular Mechanisms of Action and Their Efficacy

More than 10% of the world's population suffers from osteoarthritis (OA) of the knee, with a lifetime risk of 45%. Current treatments for knee OA pain are as follows: weight control; oral pharmacological treatment (non-steroidal anti-inflammatory drugs, paracetamol, opioids); mechanical aids (crutches, walkers, braces, orthotics); therapeutic physical exercise; and intraarticular injections of corticosteroids, hyaluronic acid, and platelet-rich plasma (PRP). The problem is that such treatments usually relieve joint pain for only a short period of time. With respect to intraarticular injections, corticosteroids relieve pain for several weeks, while hyaluronic acid and PRP relieve pain for several months. When the above treatments fail to control knee pain, total knee arthroplasty (TKA) is usually indicated; however, although a very effective surgical technique, it can be associated with medical and postoperative (surgery-related) complications. Therefore, it seems essential to look for safe and effective alternative treatments to TKA. Recently, there has been much research on intraarticular injections of mesenchymal stem cells (MSCs) for the management of OA of the knee joint. This article reviews the latest information on the molecular mechanisms of action of MSCs and their potential therapeutic benefit in clinical practice in patients with painful knee OA. Although most recent publications claim that intraarticular injections of MSCs relieve joint pain in the short term, their efficacy remains controversial given that the existing scientific information on MSCs is indecisive. Before recommending intraarticular MSCs injections routinely in patients with painful knee OA, more studies comparing MSCs with placebo are needed. Furthermore, a standard protocol for intraarticular injections of MSCs in knee OA is needed.