Mesenchymal stem cells: Cell therapy and regeneration potential

Regulatory of miRNAs in tri-lineage differentiation of C3H10T1/2

MicroRNAs (miRNAs) are non-coding single-stranded RNA molecules encoded by endogenous genes, which play a vital role in cell generation, metabolism, apoptosis and stem cell differentiation. C3H10T1/2, a mesenchymal cell extracted from mouse embryos, is capable of osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation. Extensive studies have shown that not only miRNAs can directly trigger targeted genes to regulate the tri-lineage differentiation of C3H10T1/2, but it also can indirectly regulate the differentiation by triggering different signaling pathways or various downstream molecules. This paper aims to clarify the regulatory roles of different miRNAs on C3H10T1/2 differentiation, and discussing their balance effect among osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation of C3H10T1/2. We also review the biogenesis of miRNAs, Wnt signaling pathways, MAPK signaling pathways and BMP signaling pathways and provide some specific examples of how these signaling pathways act on C3H10T1/2 tri-lineage differentiation. On this basis, we hope that a deeper understanding of the differentiation and regulation mechanism of miRNAs in C3H10T1/2 can provide a promising therapeutic method for the clinical treatment of bone defects, osteoporosis, osteoarthritis and other diseases.

Mesenchymal Stem Cells and MSCs-Derived Extracellular Vesicles in Infectious Diseases: From Basic Research to Clinical Practice

Mesenchymal stem cells (MSCs) are attractive in various fields of regenerative medicine due to their therapeutic potential and complex unique properties. Basic stem cell research and the global COVID-19 pandemic have given impetus to the development of cell therapy for infectious diseases. The aim of this review was to systematize scientific data on the applications of mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (MSC-EVs) in the combined treatment of infectious diseases. Application of MSCs and MSC-EVs in the treatment of infectious diseases has immunomodulatory, anti-inflammatory, and antibacterial effects, and also promotes the restoration of the epithelium and stimulates tissue regeneration. The use of MSC-EVs is a promising cell-free treatment strategy that allows solving the problems associated with the safety of cell therapy and increasing its effectiveness. In this review, experimental data and clinical trials based on MSCs and MSC-EVs for the treatment of infectious diseases are presented. MSCs and MSC-EVs can be a promising tool for the treatment of various infectious diseases, particularly in combination with antiviral drugs. Employment of MSC-derived EVs represents a more promising strategy for cell-free treatment, demonstrating a high therapeutic potential in preclinical studies.

Generation of Functional Immortalized Human Corneal Stromal Stem Cells

In addition to their therapeutic potential in regenerative medicine, human corneal stromal stem cells (CSSCs) could serve as a powerful tool for drug discovery and development. Variations from different donors, their isolation method, and their limited life span in culture hinder the utility of primary human CSSCs. To address these limitations, this study aims to establish and characterize immortalized CSSC lines (imCSSC) generated from primary human CSSCs. Primary CSSCs (pCSSC), isolated from human adult corneoscleral tissue, were transduced with ectopic expression of hTERT, c-MYC, or the large T antigen of the Simian virus 40 (SV40T) to generate imCSSC. Cellular morphology, proliferation capacity, and expression of CSSCs specific surface markers were investigated in all cell lines, including TNFAIP6 gene expression levels in vitro, a known biomarker of in vivo anti-inflammatory efficacy. SV40T-overexpressing imCSSC successfully extended the lifespan of pCSSC while retaining a similar morphology, proliferative capacity, multilineage differentiation potential, and anti-inflammatory properties. The current study serves as a proof-of-concept that immortalization of CSSCs could enable a large-scale source of CSSC for use in regenerative medicine.

Pancreatic Lineage Cell Differentiation of Bone Marrow Mesenchymal Stromal Cells on Acellular Pancreatic Bioscaffold

OBJECTIVES

We evaluated the potential differentiation ability of bone mesenchymal stromal cells (BMSCs) into pancreatic lineage cells on a rat acellular pancreatic bioscaffold (APB) and the effect of differentiated BMSCs in vivo.

METHODS

The BMSCs were dynamically or statically cultured with or without growth factor in both culture systems. We assessed the cytological behavior and differentiation. We also evaluated the pancreatic fibrosis and pathological scores.

RESULTS

The proliferation rates of BMSCs were significantly higher in the APB groups. The APB induced BMSCs to express mRNA markers at higher levels. All tested pancreatic functional proteins were also expressed at higher levels in the APB group. The secretion of metabolic enzymes was higher in the APB system. The ultrastructure of BMSCs in the APB group further revealed the morphological characteristics of pancreatic-like cells. For the in vivo study, the pancreatic fibrosis and pathological scores were significantly lower in the differentiated BMSCs group. In addition, in both the in vitro and the in vivo study, growth factor significantly improved proliferation, differentiation, and pancreatic cell therapy.

CONCLUSIONS

The APB can promote BMSC differentiation toward pancreatic lineage and pancreatic-like phenotypes, giving it the potential for use in pancreatic cell therapies and tissue engineering.

Salvianolic acid B combined with bone marrow mesenchymal stem cells piggybacked on HAMA hydrogel re-transplantation improves intervertebral disc degeneration

Cell-based tissue engineering approaches have emerged as a realistic alternative for regenerative disc tissue repair. The multidirectional differentiation potential of bone marrow mesenchymal stem cells (BMSCs) to treat disc degeneration intervertebral disc degeneration has also become a viable option. We used 1% HAMA hydrogel as a carrier and co-encapsulated BMSCs and Salvianolic acid B (SalB) into the hydrogel to reduce the apoptosis of the transplanted cells. The protective effect of SalB on BMSCs was first verified in vitro using the CCK8 method, flow cytometry, and Western-Blotting, and the physical properties and biocompatibility of HAMA hydrogels were verified in vitro. The rat model was then established using the pinprick method and taken at 4 and 8 W, to examine the extent of disc degeneration by histology and immunohistochemistry, respectively. It was found that SalB could effectively reduce the apoptosis of BMSCs in vitro by activating the JAK2-STAT3 pathway. 1% HAMA hydrogels had larger pore size and better water retention, and the percentage of cell survival within the hydrogels was significantly higher after the addition of SalB to the HAMA hydrogels. In the in vivo setting, the HAMA + SalB + BMSCs group had a more pronounced delaying effect on the progression of disc degeneration compared to the other treatment groups. The method used in this study to encapsulate protective drugs with stem cells in a hydrogel for injection into the lesion has potential research value in the field of regenerative medicine.

Strategies to improve the effect of mesenchymal stem cell therapy on inflammatory bowel disease

Inflammatory bowel disease (IBD) includes Crohn’s disease and ulcerative colitis and is an idiopathic, chronic inflammatory disease of the colonic mucosa. The occurrence of IBD, causes irreversible damage to the colon and increases the risk of carcinoma. The routine clinical treatment of IBD includes drug treatment, endoscopic treatment and surgery. The vast majority of patients are treated with drugs and biological agents, but the complete cure of IBD is difficult. Mesenchymal stem cells (MSCs) have become a new type of cell therapy for the treatment of IBD due to their immunomodulatory and nutritional functions, which have been confirmed in many clinical trials. This review discusses some potential mechanisms of MSCs in the treatment of IBD, summarizes the experimental results, and provides new insights to enhance the therapeutic effects of MSCs in future applications.

RNAa-mediated epigenetic attenuation of the cell senescence via locus specific induction of endogenous SIRT1

SIRT1, a known regulator of cellular senescence, is a therapeutic target for age related disorders and its upregulation is a strategy to improve the cell therapeutic potentials of human mesenchymal stem cell (MSCs). Knockdown of natural antisense transcripts via small activating RNAs (RNAa) is an emerging approach for safe and locus specific gene regulation. We have recently identified a natural antisense transcript at human SIRT1 locus (SIRT1-NAT), the expression of which shows a negative correlation with that of SIRT1. To test the hypothetic upregulation of SIRT1 via knockdown of SIRT1-NAT, in this study we designed a single stranded oligonucleotide (SIRT1-antagoNAT) against the antisense transcript, transfection of which efficiently knocked down the SIRT1-NAT and induced SIRT1 transcription in human MSCs. In addition, activation of SIRT1 transfection via knockdown of SIRT1-NAT in human MSCs enhanced their proliferation and differentiation potentials, reduced senescence associated β-galactosidase activity and reversed the senescence associated molecular alterations. Our findings introduce an RNAa mediated approach for epigenetic induction of endogenous SIRT1 and the consequent attenuation of senescence. Further studies should evaluate the therapeutic potentials of this approach against various age related disorders.

The potential of plant extracts in cell therapy

Cell therapy is the frontier technology of biotechnology innovation and the most promising method for the treatment of refractory diseases such as tumours. However, cell therapy has disadvantages, such as toxicity and poor therapeutic effects. Plant extracts are natural, widely available, and contain active small molecule ingredients that are widely used in the treatment of various diseases. By studying the effect of plant extracts on cell therapy, active plant extracts that have positive significance in cell therapy can be discovered, and certain contributions to solving the current problems of attenuation and adjuvant therapy in cell therapy can be made. Therefore, this article reviews the currently reported effects of plant extracts in stem cell therapy and immune cell therapy, especially the effects of plant extracts on the proliferation and differentiation of mesenchymal stem cells and nerve stem cells and the potential role of plant extracts in chimeric antigen receptor T-cell immunotherapy (CAR-T) and T-cell receptor modified T-cell immunotherapy (TCR-T), in the hope of encouraging further research and clinical application of plant extracts in cell therapy.

Overexpression of PYGO1 promotes early cardiac lineage development in human umbilical cord mesenchymal stromal/stem cells by activating the Wnt/β-catenin pathway

Cardiovascular disease still has the highest mortality. Gene-modified mesenchymal stromal/stem cells could be a promising therapy. Pygo plays an important role in embryonic development and regulates life activities with a variety of regulatory mechanisms. Therefore, this study aimed to investigate whether the overexpression of the PYGO1 gene can promote the differentiation of human umbilical cord-derived mesenchymal stromal/stem cells (HUC-MSCs) into early cardiac lineage cells and to preliminary explore the relevant mechanisms. In this study, HUC-MSCs were isolated by the explant method and were identified by flow cytometry and differentiation assay, followed by transfected with lentivirus carrying the PYGO1 plasmid. In PYGO1 group (cells were incubated with lentiviral-PYGO1), the mRNA expressions of cardiac differentiation-specific markers (MESP1, NKX2.5, GATA4, MEF2C, ISL1, TBX5, TNNT2, ACTC1, and MYH6 genes) and the protein expressions of NKX2.5 and cTnT were significantly up-regulated compared with the NC group (cells were incubated with lentiviral-empty vector). In addition, the proportion of NKX2.5, GATA4, and cTnT immunofluorescence-positive cells increased with the inducement time. Overexpression of PYGO1 statistically significantly increased the relative luciferase expression level of Topflash plasmid, the protein expression level of β-catenin and the mRNA expression level of CYCLIND1. Compared with the control group, decreased protein levels of NKX2.5 and cTnT were detected in PYGO1 group after application of XAV-939, the specific inhibitor of the canonical Wnt/β-catenin pathway. Our study suggests that overexpression of PYGO1 significantly promotes the differentiation of HUC-MSCs into early cardiac lineage cells, which is regulated by the canonical Wnt/β-catenin signaling.

Cytoprotection of Human Progenitor and Stem Cells through Encapsulation in Alginate Templated, Dual Crosslinked Silk and Silk-Gelatin Composite Hydrogel Microbeads

Susceptibility of mammalian cells against harsh processing conditions limit their use in cell transplantation and tissue engineering applications. Besides modulation of the cell microenvironment, encapsulation of mammalian cells within hydrogel microbeads attract attention for cytoprotection through physical isolation of the encapsulated cells. The hydrogel formulations used for cell microencapsulation are largely dominated by ionically crosslinked alginate (Alg), which suffer from low structural stability under physiological culture conditions and poor cell-matrix interactions. Here the fabrication of Alg templated silk and silk/gelatin composite hydrogel microspheres with permanent or on-demand cleavable enzymatic crosslinks using simple and cost-effective centrifugation-based droplet processing are demonstrated. The composite microbeads display structural stability under ion exchange conditions with improved mechanical properties compared to ionically crosslinked Alg microspheres. Human mesenchymal stem and neural progenitor cells are successfully encapsulated in the composite beads and protected against environmental factors, including exposure to polycations, extracellular acidosis, apoptotic cytokines, ultraviolet (UV) irradiation, anoikis, immune recognition, and particularly mechanical stress. The microbeads preserve viability, growth, and differentiation of encapsulated stem and progenitor cells after extrusion in viscous polyethylene oxide solution through a 27-gauge fine needle, suggesting potential applications in injection-based delivery and three-dimensional bioprinting of mammalian cells with higher success rates.

Biomaterials constructed for MSC-derived extracellular vesicle loading and delivery—a promising method for tissue regeneration

Mesenchymal stem cells (MSCs) have become the preferred seed cells for tissue regeneration. Nevertheless, due to their immunogenicity and tumorigenicity, MSC transplantation remains questionable. Extracellular vesicles (EVs) derived from MSCs are becoming a promising substitute for MSCs. As a route of the MSC paracrine, EVs have a nano-sized and bilayer lipid-enclosed structure, which can guarantee the integrity of their cargoes, but EVs cannot obtain full function in vivo because of the rapid biodegradation and clearance by phagocytosis. To improve the efficacy and targeting of EVs, methods have been proposed and put into practice, especially engineered vesicles and EV-controlled release systems. In particular, EVs can be cell or tissue targeting because they have cell-specific ligands on their surfaces, but their targeting ability may be eliminated by the biodegradation of the phagocytic system during circulation. Novel application strategies have been proposed beyond direct injecting. EV carriers such as biodegradable hydrogels and other loading systems have been applied in tissue regeneration, and EV engineering is also a brand-new method for higher efficacy. In this review, we distinctively summarize EV engineering and loading system construction methods, emphasizing targeting modification methods and controlled release systems for EVs, which few literature reviews have involved.

A chemically defined biomimetic surface for enhanced isolation efficiency of high-quality human mesenchymal stromal cells under xenogeneic/serum-free conditions

BACKGROUND AIMS

Mesenchymal stromal cells (MSCs) are one of the most frequently used cell types in regenerative medicine and cell therapy. Generating sufficient cell numbers for MSC-based therapies is constrained by (i) their low abundance in tissues of origin, which imposes the need for significant ex vivo cell expansion; (ii) donor-specific characteristics, including MSC frequency/quality, that decline with disease state and increasing age; and (iii) cellular senescence, which is promoted by extensive cell expansion and results in decreased therapeutic functionality. The final yield of a manufacturing process is therefore primarily determined by the applied isolation procedure and its efficiency in isolating therapeutically active cells from donor tissue. To date, MSCs are predominantly isolated using media supplemented with either serum or its derivatives, which poses safety and consistency issues.

METHODS

To overcome these limitations while enabling robust MSC production with constant high yield and quality, the authors developed a chemically defined biomimetic surface coating called isoMATRIX (denovoMATRIX GmbH, Dresden, Germany) and tested its performance during isolation of MSCs.

RESULTS

The isoMATRIX facilitates the isolation of significantly higher numbers of MSCs in xenogeneic (xeno)/serum-free and chemically defined conditions. The isolated cells display a smaller cell size and higher proliferation rate than those derived from a serum-containing isolation procedure and a strong immunomodulatory capacity. The high proliferation rates can be maintained up to 5 passages after isolation and cells even benefit from a switch towards a proliferation-specific MSC matrix (myMATRIX MSC) (denovoMATRIX GmbH, Dresden, Germany).

CONCLUSION

In sum, isoMATRIX promotes enhanced xeno/serum-free and chemically defined isolation of human MSCs and supports consistent and reliable cell performance for improved stem cell-based therapies.

Effect of Puerarin on Osteogenic Differentiation in vitro and on New Bone Formation in vivo

Purpose

Puerarin (C₂₁H₂₀O₁₀) is a phytoestrogen that possesses various pharmacological effect, and several researches have revealed the relationship between puerarin and bone metabolism. This study was aimed to evaluate the potential influence of puerarin on the proliferation and osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (BMSCs) as well as on new bone formation following rapid maxillary expansion (RME) model in rats.

Methods

Rat BMSCs were adopted, and the cell proliferation was detected by cell-counting kit-8 (CCK-8) assay in vitro experiments. Alkaline phosphatase (ALP) activity and alizarin red staining were analyzed quantitatively to show extracellular matrix mineralization. The mRNA and protein expression levels were used to detect osteogenic differentiation of BMSCs. In vivo bone regeneration was analyzed in a rat RME model. Eighteen 6-week-old male Wistar rats were divided into 3 groups: group 1 without any treatment, group 2 received RME and saline solution (15mg/kg), group 3 received RME and puerarin solution (15mg/kg). After 2 weeks, micro-computed tomography (Micro-CT), hematoxylin and eosin (HE) staining, and Masson staining were used to detect the new bone formation and morphological changes. Besides, ALP and bone morphogenetic protein 2 (BMP2) expression levels in mid-palatal suture were evaluated by immunohistochemical staining.

Results

The results showed that puerarin upregulates cell proliferation dose-dependently. ALP activity and mineralized matrix generation were clearly enhanced at certain specific concentrations (10⁻⁵ and 10⁻⁶ mol/L); the expression levels of the osteoblast-related genes and proteins were increased. The measurement of micro-CT imaging revealed that puerarin significantly promoted new bone formation. Concomitantly, the histological examinations showed that puerarin solution enhanced osteogenesis in mid-palatal suture.

Conclusion

Those works indicated that puerarin regulates osteogenesis in vitro and exerts a beneficial impact on bone regeneration in vivo, revealing that puerarin treatment may become one of the potential keys for improving the stability and preventing relapse of RME.

Role of hypoxia preconditioning in therapeutic potential of mesenchymal stem-cell-derived extracellular vesicles

The use of mesenchymal stem-cells (MSC) in cell therapy has received considerable attention because of their properties. These properties include high expansion and differentiation in vitro, low immunogenicity, and modulation of biological processes, such as inflammation, angiogenesis and hematopoiesis. Curiously, the regenerative effect of MSC is partly due to their paracrine activity. This has prompted numerous studies, to investigate the therapeutic potential of their secretome in general, and specifically their extracellular vesicles (EV). The latter contain proteins, lipids, nucleic acids, and other metabolites, which can cause physiological changes when released into recipient cells. Interestingly, contents of EV can be modulated by preconditioning MSC under different culture conditions. Among them, exposure to hypoxia stands out; these cells respond by activating hypoxia-inducible factor (HIF) at low O₂ concentrations. HIF has direct and indirect pleiotropic effects, modulating expression of hundreds of genes involved in processes such as inflammation, migration, proliferation, differentiation, angiogenesis, metabolism, and cell apoptosis. Expression of these genes is reflected in the contents of secreted EV. Interestingly, numerous studies show that MSC-derived EV conditioned under hypoxia have a higher regenerative capacity than those obtained under normoxia. In this review, we show the implications of hypoxia responses in relation to tissue regeneration. In addition, hypoxia preconditioning of MSC is being evaluated as a very attractive strategy for isolation of EV, with a high potential for clinical use in regenerative medicine that can be applied to different pathologies.

Application of exosome-derived noncoding RNAs in bone regeneration: Opportunities and challenges

With advances in the fields of regenerative medicine, cell-free therapy has received increased attention. Exosomes have a variety of endogenous properties that provide stability for molecular transport across biological barriers to cells, as a form of cell-to-cell communication that regulates function and phenotype. In addition, exosomes are an important component of paracrine signaling in stem-cell-based therapy and can be used as a stand-alone therapy or as a drug delivery system. The remarkable potential of exosomes has paved the pathway for cell-free treatment in bone regeneration. Exosomes are enriched in distinct noncoding RNAs (ncRNAs), including microRNAs, long ncRNAs and circular RNAs. Different ncRNAs have multiple functions. Altered expression of ncRNA in exosomes is associated with the regenerative potential and development of various diseases, such as femoral head osteonecrosis, myocardial infarction, and cancer. Although there is increasing evidence that exosome-derived ncRNAs (exo-ncRNAs) have the potential for bone regeneration, the detailed mechanisms are not fully understood. Here, we review the biogenesis of exo-ncRNA and the effects of ncRNAs on angiogenesis and osteoblast- and osteoclast-related pathways in different diseases. However, there are still many unsolved problems and challenges in the clinical application of ncRNA; for instance, production, storage, targeted delivery and therapeutic potency assessment. Advancements in exo-ncRNA methods and design will promote the development of therapeutics, revolutionizing the present landscape.

Effect of Recombinant Netrin-1 Protein Combined with Peripheral Blood Mesenchymal Stem Cells on Angiogenesis in Rats with Arteriosclerosis Obliterans

This work was aimed to explore the effect of recombinant netrin-1 protein and peripheral blood mesenchymal stem cells (MSCs) on the angiogenesis ability of atherosclerosis. 28 Sprague Dawley (SD) rats were taken as research models. The arterial occlusion models were created by surgery and then divided into the saline control group (n =7), netrin-1 treatment group (n =7), MSCs treatment group (n =7), and netrin-1 + MSCs combined treatment group (n =7). The peripheral blood MSCs were extracted from the peritoneal cavity of diseased SD rats and cultured alone or in combination with netrin-1. The individually cultured MSCs and netrin-1 were locally injected into the ischemic tissues of SD rats. The Tarlov scoring was performed at the first, second, and third week of treatment, respectively. The expression of vascular endothelial growth factor (VEGF) was also measured by quantitative real-time polymerase chain reaction (qRT-PCR), and the capillary density was measured by immunofluorescence staining. The mean maximum contractility of the gastrocnemius muscle in each group was determined in the third week after treatment. The Tarlov score of the netrin-1 + MSCs group was significantly higher than that of the control group (P < 0.05) at the second week. To the 4th week of treatment, the Tarlov score of the netrin-1 + MSCs group was highly increased compared to the netrin-1 group and the MSCs group (P < 0.05). The expression of VEGF in the treatment groups was greatly increased each week compared to the control group (P < 0.05). Compared with the netrin-1 and the MSCs groups, the VEGF was also notably increased in the netrin-1 + MSCs group (P <0.05). The capillary densities of the treatment groups were observably greater than that of the control group in the second and third weeks (P <0.05), while the capillary density in the netrin-1 + MSCs group was also significantly increased than those in the netrin-1 group and the MSCs group (P < 0.05). The mean maximum contractility of the netrin-1 + MSCs group was remarkably higher than that of the other groups (P < 0.05). The netrin-1 + MSCs group achieved the higher Tarlov score, higher VEGF expression, higher capillary density, and better muscle recovery than netrin-1 and MSCs treatments.

Differences in chemotaxis of human mesenchymal stem cells and cervical cancer cells

In the last decade, there has been a rapid expansion in tumor targeted therapy using mesenchymal stem cells (MSCs) based on their unique tropism towards cancer cells. Despite similarities in morphology, immunophenotype, and differential potent in vitro, MSCs originated from different tissues do not necessarily have equivalent biological behaviors. It is important to screen the most chemotactic MSCs to cancer cells. In this study, different MSCs were isolated from various human tissues including adipose, umbilical cord, amniotic membrane, and chorion. The chemotaxis of human MSCs to cervical cancer cells was measured by CCK-8, ELISA and Transwell invasion assays. Western blotting was performed to explore the underlying mechanisms. MSCs derived from distinct sources can be differently recruited to cervical cancer cells, among which chorion-derived MSC (CD-MSC) possessed the strongest tropic capacity. CXCL12 was found to be highly secreted by cervical cancer cells, in parallel with the expression of CXCR4 in all MSCs. CD-MSC displayed the highest level of CXCR4. These results indicated that CXCL12/CXCR4 pathway contributed to the different chemotaxis to cervical cancer cells of each MSCs. This study proposed that CD-MSC with the highest CXCR4 expression is a promising therapeutic vehicle for targeted therapy in cervical cancer.

Combination Therapy Using Nanomaterials and Stem Cells to Treat Spinal Cord Injuries

As a part of the central nervous system, the spinal cord (SC) provides most of the communications between the brain and other parts of the body. Any damage to SC interrupts this communication, leading to serious problems, which may remain for the rest of their life. Due to its significant impact on patients' quality of life and its exorbitant medical costs, SC injury (SCI) is known as one of the most challengeable diseases in the world. Thus, it is critical to introduce highly translatable therapeutic platforms for SCI treatment. So far, different strategies have been introduced, among which utilizing various types of stem cells is one of the most interesting ones. The capability of stem cells to differentiate into several types of cell lines makes them promising candidates for the regeneration of injured tissues. One of the other interesting and novel strategies for SCI treatment is the application of nanomaterials, which could appear as a carrier for therapeutic agents or as a platform for culturing the cells. Combining these two approaches, stem cells and nanomaterials, could provide promising therapeutic strategies for SCI management. Accordingly, in this review we have summarized some of the recent advancements in which the applications of different types of stem cells and nanomaterials, alone and in combination forms, were evaluated for SCI treatment.

Conditioned medium of amniotic fluid-derived stromal cells exerts a bone anabolic effect by enhancing progenitor population and angiogenesis

A cell-free approach utilizing the paracrine effects of mesenchymal stromal cells is receiving attention in regenerative medicine. In the present study, we evaluated the effects of a conditioned medium of amniotic fluid-derived stromal cells (AFSC-CM) on bone metabolism. In mice, intraperitoneal injections of AFSC-CM increased bone mass and enhanced bone turnover. The precursor populations of myeloid and mesenchymal lineages, as well as endothelial cells in bone marrow, were also augmented by AFSC-CM administration. In an in vitro culture experiment, AFSC-CM increased osteoclast differentiation of bone marrow-derived macrophages, but had no significant effect on the osteogenic differentiation of preosteoblasts. However, AFSC-CM administration dramatically accelerated the migration and tube formation of endothelial cells, and a cytokine array showed that AFSC-CM contained many angiogenic factors. These results indicate that AFSC-CM exerts a bone anabolic effect by changing the bone marrow microenvironment, including angiogenesis and precursor expansion. Therefore, ameliorating marrow angiogenesis is a potential therapeutic strategy for bone regeneration, for which AFSCs can be a good cellular source.

Advances in the Regulation of Macrophage Polarization by Mesenchymal Stem Cells and Implications for ALI/ARDS Treatment

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a common condition with high mortality. ALI/ARDS is caused by multiple etiologies, and the main clinical manifestations are progressive dyspnea and intractable hypoxemia. Currently, supportive therapy is the main ALI/ARDS treatment, and there remains a lack of targeted and effective therapeutic strategies. Macrophages are important components of innate immunity. M1 macrophages are pro-inflammatory, while M2 macrophages are anti-inflammatory and promote tissue repair. Mesenchymal stem cells (MSCs) are stem cells with broad application prospects in tissue regeneration due to their multi-directional differentiation potential along with their anti-inflammatory and paracrine properties. MSCs can regulate the balance of M1/M2 macrophage polarization to improve the prognosis of ALI/ARDS. In this paper, we review the mechanisms by which MSCs regulate macrophage polarization and the signaling pathways associated with polarization. This review is expected to provide new targets for the treatment of ALI/ARDS.

Mesenchymal Stem Cells Promote IL-6 Secretion and Suppress the Gene Expression of Proinflammatory Cytokines in Contractile C2C12 Myotubes

Sarcopenia is not only a major cause of disability but also a risk factor for obesity and diabetes in elderly persons. Exercise is an effective method for improving the sarcopenic condition by inducing the secretion of interleukin (IL)-6, which has the capacities to both promote muscle hypertrophy and regulate lipid metabolism and glucose homeostasis, by skeletal muscle. We previously showed that mesenchymal stem cells (MSCs) promote IL-6 secretion by lipopolysaccharide-stimulated C2C12 mouse skeletal muscle myotubes via paracrine mechanisms. Therefore, in this study, we investigated the effect of paracrine actions of MSCs on IL-6 and proinflammatory cytokine expression in contractile C2C12 myotubes by applying electrical stimulation. IL-6 secretion by C2C12 myotubes was increased by electrical stimulation, and a more significant increase in IL-6 secretion was observed in electrically stimulated C2C12 myotubes cultured in conditioned medium from MSCs. The activation of nuclear factor-κB in C2C12 myotubes was also promoted by the combination of conditioned medium from MSCs and electrical stimulation. Moreover, the increases in tumor necrosis factor-α and IL-1β mRNA expression in C2C12 myotubes induced by electrical stimulation were suppressed by culture in conditioned medium from MSCs. The present findings suggest that MSCs transplantation or injection of their extracellular vesicles improve the therapeutic effect of exercise against sarcopenia without exacerbating inflammation.

Stem cells as an option for the treatment of COVID-19

The application of stem cells is among the many strategies currently available for the treatment of multiple diseases. Stem cells are characterized as undifferentiated cells that have the ability to differentiate towards multiple lineages and self-renewal, among other attributes. Since the first umbilical cord stem cell transplant for the treatment of Fanconi anemia, the use of stem cells for the treatment of multiple diseases, including coronavirus disease 2019, has increased, showing promising results that require evaluation through research studies that include a longer follow-up time. Therefore, the main objective of this Letter is to provide an update on the use of stem cells in the treatment of severe acute respiratory syndrome coronavirus 2, as well as identify the main challenges and limitations presented by this type of therapy.

Mesenchymal stem cell transplantation in newly diagnosed type-1 diabetes patients: a phase I/II randomized placebo-controlled clinical trial

Background

Type-1 diabetes (T1D) occurs following autoimmune-induced pancreatic beta cells death. Among several treatment modalities, mesenchymal stem cells (MSCs) transplantation is promising for autoimmune disorders due to immunomodulation, regeneration, and migration to damaged tissue upon systemic injection. This study assessed the safety and efficacy of intravenous injection of autologous bone marrow-derived MSCs in newly diagnosed T1D patients.

Methods

After receiving informed consent, 21 patients who met the study criteria were enrolled and randomly assigned to receive either MSCs or placebo. Each patient in the experimental group received two doses of MSCs and was followed for at least one-year post-transplantation.

Results

The results have shown that this transplantation is safe and significantly reduces the number of hypoglycemic episodes. MSCs transplantation improved glycated hemoglobin (HbA1c), shifted serum cytokine patterns from pro-inflammatory to anti-inflammatory, increased the number of regulatory T-cells in the peripheral blood, and improved quality of life. Early transplantation of MSCs significantly improved HbA1c and C-peptide levels and shifted pro-inflammatory cytokines to anti-inflammatory cytokines. Also, exercise combined with MSCs transplantation improved glycemic and immunologic indices.

Conclusions

Taken together, autologous MSC transplantation is safe and effective, and its early transplantation is a promising treatment in newly diagnosed T1D children suffering from hypoglycemic episodes.

Trial registration: This clinical trial was registered at the Iranian Registry of Clinical Trials (IRCT) with the identifier IRCT ID: IRCT2016070428786N1 registered on August 20, 2016 (Retrospectively registered) (https://en.irct.ir/trial/23256) and at the U.S. National Institutes of Health (ClinicalTrials.gov) with the related identifier NCT04078308 registered on September 6, 2019 (Retrospectively registered). (https://clinicaltrials.gov/ct2/show/NCT04078308).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02941-w.

Athletes' Mesenchymal Stem Cells Could Be the Best Choice for Cell Therapy in Omicron-Infected Patients

New severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, Omicron, contains 32 mutations that have caused a high incidence of breakthrough infections or re-infections. These mutations have reduced vaccine protection against Omicron and other new emerging variants. This highlights the need to find effective treatment, which is suggested to be stem cell-based therapy. Stem cells could support respiratory epithelial cells and they could restore alveolar bioenergetics. In addition, they can increase the secretion of immunomodulatory cytokines. However, after transplantation, cell survival and growth rate are low because of an inappropriate microenvironment, and stem cells face ischemia, inflammation, and oxidative stress in the transplantation niche which reduces the cells' survival and growth. Exercise-training can upregulate antioxidant, anti-inflammatory, and anti-apoptotic defense mechanisms and increase growth signaling, thereby improving transplanted cells' survival and growth. Hence, using athletes' stem cells may increase stem-cell therapy outcomes in Omicron-affected patients.

MAPK/ERK-CBP-RFPL-3 Mediates Adipose-Derived Stem Cell-Induced Tumor Growth in Breast Cancer Cells by Activating Telomerase Reverse Transcriptase Expression

Adipose-derived stem cells (ASCs) improve the self-renewal and survival of fat grafts in breast reconstruction after oncology surgery. However, ASCs have also been found to enhance breast cancer growth, and its role in tumor proliferation remains largely elusive. Here, we explored a novel mechanism that mediates hTERT reactivation during ASC-induced tumor growth in breast cancer cells. In this study, we found the proliferative ability of breast cancer cells markedly increased with ASC coculture. To explore the molecular mechanism, we treated cells with anibody/inhibitor and found that the activation of MEK-ERK pathway was triggered in breast cancer cells by SCF secreted from ASCs, leading to the nuclear recruitment of CBP. As a coactivator of hTERT, CBP subsequently coordinated with RFPL-3 upregulated hTERT transcription and telomerase activity. The inhibition of CBP and RFPL-3 abrogated the activation of hTERT transcription and the promotion of proliferation in breast cancer cells with cocultured ASCs in vitro and in vivo. Collectively, our study findings indicated that CBP coordination with RFPL-3 promotes ASC-induced breast cancer cell proliferation by anchoring to the hTERT promoter and upregulating telomerase activity, which is activated by the MAPK/ERK pathway.

Autophagy reprogramming stem cell pluripotency and multiple-lineage differentiation

The cellular process responsible for the degradation of cytosolic proteins and subcellular organelles in lysosomes was termed "autophagy." This process occurs at a basal level in most tissues as part of tissue homeostasis that redounds to the regular turnover of components inside cytoplasm. The breakthrough in the autophagy field is the identification of key players in the autophagy pathway, compounded under the name "autophagy-related genes" (ATG) encoding for autophagy effector proteins. Generally, the function of autophagy can be classified into two divisions: intracellular clearance of defective macromolecules and organelles and generation of degradation products. Therapeutic strategies using stem cell-based approach come as a promising therapy and develop rapidly recently as stem cells have high self-renewability and differentiation capability as known as mesenchymal stem cells (MSCs). They are defined as adherent fibroblast-like population with the abilities to self-renew and multi-lineage differentiate into osteogenic, adipogenic, and chondrogenic lineage cells. To date, they are the most extensively applied adult stem cells in clinical trials. The properties of MSCs, such as immunomodulation, neuroprotection, and tissue repair pertaining to cell differentiation, processes to replace lost, or damaged cells, for aiding cell repair and revival. Autophagy has been viewed as a remarkable mechanism for maintaining homeostasis, ensuring the adequate function and survival of long-lived stem cells. In addition, authophagy also plays a remarkable role in protecting stem cells against cellular stress when the stem cell regenerative capacity is harmed in aging and cellular degeneration. Understanding the under-explored mechanisms of MSC actions and expanding the spectrum of their clinical applications may improve the utility of the MSC-based therapeutic approach in the future.

Quality assessment of a serum and xenofree medium for the expansion of human GMP-grade mesenchymal stromal cells

Background

Cell-based therapies are emerging as a viable modality to treat challenging diseases, resulting in an increasing demand for their large-scale, high-quality production. Production facilities face the issue of batch-to-batch consistency while producing a safe and efficient cell-based product. Controlling culture conditions and particularly media composition is a key factor of success in this challenge. Serum and Xeno-Free Media (SXFM) represent an interesting option to achieve this goal. By reducing batch to batch variability, they increase Good Manufacturing Practices (GMP)-compliance and safety regarding xenogenic transmission, as compared to fetal bovine serum (FBS) supplemented-media or human platelet lysate supplemented medium.

Methods

In this study, the isolation, expansion and characteristics including the anti-inflammatory function of human mesenchymal stromal cells (MSC) are compared after culture in MEMα supplemented with human Concentrate Platelet Lysate (hCPL, reference medium) or in MSC-Brew GMP Medium. The latter is a GMP SXFM manufactured in bags under strictly controlled conditions in volumes suitable for expansion to a clinical scale and does not require neither pre-coating of the cell culture units nor the addition of blood derivatives at the isolation step.

Results

We showed that MSC derived from human bone-marrow and adipose tissue can be successfully isolated and expanded in this SXFM. Number and size of Colony-Forming Unit fibroblast (CFU-F) is increased compared to cells cultivated in hCPL medium. All cells retained a CD90⁺, CD73⁺, CD105⁺, HLADR^-, CD34^-, CD45^- phenotype. Furthermore, the osteogenic and adipocyte potentials as well as the anti-inflammatory activity were comparable between culture conditions. All cells reached the release criteria established in our production facility to treat inflammatory pathologies.

Conclusions

The use of MSC-Brew GMP Medium can therefore be considered for clinical bioprocesses as a safe and efficient substitute for hCPL media.

Effects of Systemic or Local Administration of Mesenchymal Stem Cells from Patients with Osteoporosis or Osteoarthritis on Femoral Fracture Healing in a Mouse Model

The purpose of this study was to analyze the regenerative capacity of mesenchymal stem cells (MSCs) in the treatment of fractures. MSCs extracted from patients with osteoporotic hip fractures or hip osteoarthritis undergoing hip replacement surgeries were cultured and injected into mice with femoral fracture. Two experimental models were established, one for the systemic administration of MSCs (n = 29) and another one for local administration (n = 30). Fracture consolidation was assessed by micro-CT and histology. The degree of radiological consolidation and corticalization was better with MSCs from osteoporosis than from osteoarthritis, being significant after systemic administration (p = 0.0302 consolidation; p = 0.0243 corticalization). The histological degree of consolidation was also better with MSCs from osteoporosis than from osteoarthritis. Differences in histological scores after systemic infusion were as follows: Allen, p = 0.0278; Huo, p = 0.3471; and Bone Bridge, p = 0.0935. After local administration at the fracture site, differences in histological scores were as follows: Allen, p = 0.0764; Huo, p = 0.0256; and Bone Bridge, p = 0.0012. As osteoporosis and control groups were similar, those differences depended on an inhibitory influence by MSCs from patients with osteoarthritis. In conclusion, we found an unexpected impairment of consolidation induced by MSCs from patients with osteoarthritis. However, MSCs from patients with osteoporosis compared favorably with cells from patients with osteoarthritis. In other words, based on this study and previous studies, MSCs from patients with osteoporosis do not appear to have worse bone-regenerating capabilities than MSCs from non-osteoporotic individuals of similar age.

Hypoxia Induces DPSC Differentiation versus a Neurogenic Phenotype by the Paracrine Mechanism

As previously described by several authors, dental pulp stem cells (DPSCs), when adequately stimulated, may acquire a neuronal-like phenotype acting as a favorable source of stem cells in the generation of nerves. Besides, it is known that hypoxia conditioning is capable of stimulating cell differentiation as well as survival and self-renewal, and that multiple growth factors, including Epidermal Growth factor (EGF) and basic fibroblast growth factor (bFGF), are often involved in the induction of the neuronal differentiation of progenitor cells. In this work, we investigated the role of hypoxia in the commitment of DPSCs into a neuronal phenotype. These cells were conditioned with hypoxia (O₂ 1%) for 5 and 16 days; subsequently, we analyzed the proliferation rate and morphology, and tested the cells for neural and stem markers. Moreover, we verified the possible autocrine/paracrine role of DPSCs in the induction of neural differentiation by comparing the secretome profile of the hypoxic and normoxic conditioned media (CM). Our results showed that the hypoxia-mediated DPSC differentiation was time dependent. Moreover, conditioned media (CM derived from DPSCs stimulated by hypoxia were able, in turn, to induce the neural differentiation of SH-SY5Y neuroblastoma cells and undifferentiated DPSCs. In conclusion, under the herein-mentioned conditions, hypoxia seems to favor the differentiation of DPSCs into neuron-like cells. In this way, we confirm the potential clinical utility of differentiated neuronal DPSCs, and we also suggest the even greater potential of CM-derived-hypoxic DPSCs that could more readily be used in regenerative therapies.

Application of extracellular vesicles derived from mesenchymal stem cells as potential therapeutic tools in autoimmune and rheumatic diseases

Mesenchymal stem cells (MSCs) have been proven to have superior potential to be used astherapeutic candidates in various disorders. Nevertheless, the clinical application of these cells have been restricted because of their tumorigenic properties. Increasing evidence has established that the valuable impacts of MSCs are mainly attributable to the paracrine factors including extracellular vesicles (EVs). EVs are nanosized double-layer phospholipid membrane vesicles contain various proteins, lipids and miRNAs which mediate cell-to-cell communications. Due to their inferior immunogenicity and tumorigenicity, as well as easier management, EVs have drawn attention as potential cell-free replacement therapy to MSCs. For that reason, herein, we reviewed the recent findings of researches on different MSC-EVs and their effectiveness in the treatment of several autoimmune and rheumatic diseases including multiple sclerosis, inflammatory bowel disease, rheumatoid arthritis, osteoarthritis, osteoporosis, and systemic lupus erythematosus as well as Sjogren's syndrome, systemic sclerosis and other autoimmune diseases.

Schwann Cells Promote Myogenic Differentiation of Myoblasts and Adipogenic Mesenchymal Stromal Cells on Poly-ɛ-Caprolactone-Collagen I-Nanofibers

For the purpose of skeletal muscle tissue engineering, different cell types have been investigated regarding their myogenic differentiation potential, including co-cultured myoblasts and adipogenic mesenchymal stromal cells (Mb/ADSC). As neural cells enhance synaptic junction formation, the aim of this study was to co-culture Schwann cells (SCs) with Mb/ADSC on biocompatible electrospun aligned poly-ε-polycaprolacton (PCL)-collagen I-nanofibers. It was hypothesized that SCs, as part of the peripheral nervous system, promote the myogenic differentiation of Mb/ADSC co-cultures. Mb/ADSC were compared to Mb/ADSC/SC regarding their capacity for myogenic differentiation via immunofluorescent staining and gene expression of myogenic markers. Mb/ADSC/SC showed more myotubes after 28 days of differentiation (p ≤ 0.05). After 28 days of differentiation on electrospun aligned PCL-collagen I-nanofibers, gene expression of myosin heavy chains (MYH2) and myogenin (MYOG) was upregulated in Mb/ADSC/SC compared to Mb/ADSC (p ≤ 0.01 and p ≤ 0.05, respectively). Immunofluorescent staining for MHC showed highly aligned multinucleated cells as possible myotube formation in Mb/ADSC/SC. In conclusion, SCs promote myogenic differentiation of Mb/ADSC. The co-culture of primary Mb/ADSC/SC on PCL-collagen I-nanofibers serves as a physiological model for skeletal muscle tissue engineering, applicable to future clinical applications.

Therapeutic Effects of Citrus Flavonoids Neohesperidin, Hesperidin and Its Aglycone, Hesperetin, on Bone Health

Flavonoids are natural phytochemicals that have therapeutic effects and act in the prevention of several pathologies. These phytochemicals can be found in seeds, grains, tea, coffee, wine, chocolate, cocoa, vegetables and, mainly, in citrus fruits. Neohesperidin, hesperidin and hesperetin are citrus flavonoids from the flavanones subclass that have anti-inflammatory and antioxidant potential. Neohesperidin, in the form of neohesperidin dihydrochalcone (NHDC), also has dietary properties as a sweetener. In general, these flavanones have been investigated as a strategy to control bone diseases, such as osteoporosis and osteoarthritis. In this literature review, we compiled studies that investigated the effects of neohesperidin, hesperidin and its aglycone, hesperetin, on bone health. In vitro studies showed that these flavanones exerted an antiosteoclastic and anti- inflammatory effects, inhibiting the expression of osteoclastic markers and reducing the levels of reactive oxygen species, proinflammatory cytokines and matrix metalloproteinase levels. Similarly, such studies favored the osteogenic potential of preosteoblastic cells and induced the overexpression of osteogenic markers. In vivo, these flavanones favored the regeneration of bone defects and minimized inflammation in arthritis- and periodontitis-induced models. Additionally, they exerted a significant anticatabolic effect in ovariectomy models, reducing trabecular bone loss and increasing bone mineral density. Although research should advance to the clinical field, these flavanones may have therapeutic potential for controlling the progression of metabolic, autoimmune or inflammatory bone diseases.

Stem cells to reverse aging

ABSTRACT

As human life expectancy continues to increase and the birth rate continues to decline, the phenomenon of aging is becoming more prominent worldwide. Therefore, addressing the problems associated with global aging has become a current research focus. The main manifestations of human aging are structural degeneration and functional decline of aging tissues and organs, quality of life decline, decreased ability to resist diseases, and high incidence rates of a variety of senile degenerative diseases. Thus far, no ideal treatments have been found. Stem cell (SC) therapies have broad application prospects in the field of regenerative medicine due to the inherent biological characteristics of SCs, such as their plasticity, self-renewal, and multidirectional differentiation potential. Thus, SCs could delay or even reverse aging. This manuscript reviews the causes of human aging, the biological characteristics of SCs, and research progress on age reversal.

Targeted Therapy for Inflammatory Diseases with Mesenchymal Stem Cells and Their Derived Exosomes: From Basic to Clinics

Inflammation is a beneficial and physiological process, but there are a number of inflammatory diseases which have detrimental effects on the body. In addition, the drugs used to treat inflammation have toxic side effects when used over a long period of time. Mesenchymal stem cells (MSCs) are pluripotent stem cells that can be isolated from a variety of tissues and can be differentiate into diverse cell types under appropriate conditions. They also exhibit noteworthy anti-inflammatory properties, providing new options for the treatment of inflammatory diseases. The therapeutic potential of MSCs is currently being investigated for various inflammatory diseases, such as kidney injury, lung injury, osteoarthritis (OA), rheumatoid arthritis (RA), and inflammatory bowel disease (IBD). MSCs can perform multiple functions, including immunomodulation, homing, and differentiation, to enable damaged tissues to form a balanced inflammatory and regenerative microenvironment under severe inflammatory conditions. In addition, accumulated evidence indicates that exosomes from extracellular vesicles of MSCs (MSC-Exos) play an extraordinary role, mainly by transferring their components to recipient cells. In this review, we summarize the mechanism and clinical trials of MSCs and MSC-Exos in various inflammatory diseases in detail, with a view to contributing to the treatment of MSCs and MSC-Exos in inflammatory diseases.

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

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

A novel hybrid polymer of PCL/Fish gelatin nanofibrous scaffold improves proliferation and differentiation of wharton's jelly-derived mesenchymal cells into islet-like cells

BACKGROUND

Using a different source of stem cells to compensate for the lost beta cells is a promising way to cure diabetic patients. Besides The best efficiency of insulin-producing cells (IPCs) will appear when we culture them in an environment similar to inside the body. Hence, three-dimensional (3D) culture ameliorates the differentiation of diverse kinds of stem cells into IPCs compared to those differentiated in two-dimensional (2D) culture. In this study, we aim to create an ideal differentiation environment by using PCL/Fish gelatin nanofibrous scaffolds to differentiate wharton's jelly-derived mesenchymal cells (WJ-MSCs) to IPCs and compare them with a 2D cultured group.

METHODS

The evaluation of cellular, molecular, and functional properties of differentiated cells on the 3D and 2D cultures were investigated by several assay such as electron microscopy, quantitative PCR, immunochemistry, western blotting, and ELISA.

RESULTS

The in vitro studies showed, WJ-MSCs that differentiated in the 3D culture have strong properties of IPCs such as islet-like cells. The expression of pancreatic-specific genes at both RNA and protein levels showed higher differentiation efficacy of 3D culture. Besides, the results of the elisa tests demonstrates that in both groups the differentiated cells are functional and secreted C-peptide and insulin in glucose stimulation, but the secretion of C-peptide and insulin in the 3D culture group was higher than those cultured in 2D groups.

CONCLUSION

Our findings showed the use of PCL/Fish gelatin nanofibrous scaffolds with optimized differentiation protocols can promote the differentiation of IPCs from WJ-MSCs compared to the 2D culture group.

Injectable Self-Crosslinkable Thiolated Hyaluronic Acid for Stem Cell Therapy of Atopic Dermatitis

Stem cell therapies offer great promise in regenerative medicine to reinstate the normal function of diseased tissue, thereby avoiding the need for replacement. In stem cell therapies, damaged cells are replaced or restored by regulating inflammation and the immune system. However, the low survival rate and local retention of transplanted cells pose a significant challenge. In this study, injectable self-crosslinkable hydrogels using thiol-functionalized hyaluronic acid (HA-SH) were developed to improve the efficacy of mesenchymal stem cells (MSCs) for treating atopic dermatitis (AD)-related inflammatory lesions. The gelation kinetics and mechanical properties of HA-SH hydrogels were easily tuned by varying the concentration of the polymer in the precursor solution before injection. The MSC-laden HA-SH hydrogels exhibited high cell viability (>80%) for 1 week and good in vivo biocompatibility after implantation beneath the mouse skin. Moreover, the MSC-laden HA-SH hydrogel showed increased expression of anti-inflammatory cytokines, which can alleviate the immune response. In an AD animal model, a reduction in epidermal thickness and mast cell infiltration was achieved by applying a self-crosslinkable HA-SH solution including MSCs. This HA-based injectable hydrogel represents a potential carrier of stem cells, and its strong immunomodulation capabilities can be utilized for treating inflammation-related diseases.

Human primitive mesenchymal stem cell-derived retinal progenitor cells improved neuroprotection, neurogenesis, and vision in rd12 mouse model of retinitis pigmentosa

Background

Currently, there is no treatment for retinal degenerative diseases (RDD) such as retinitis pigmentosa (RP). Stem cell-based therapies could provide promising opportunities to repair the damaged retina and restore vision. Thus far, primarily adult mesenchymal stem cells (MSCs) have been investigated in preclinical and clinical studies, and the results have not been convincing. We applied a new approach in which primitive (p) MSC-derived retinal progenitor cells (RPCs) were examined to treat retinal degeneration in an rd12 mouse model of RP.

Methods

Well-characterized pMSCs and RPCs labeled with PKH26 were intravitreally injected into rd12 mice. The vision and retinal function of transplanted animals were analyzed using electroretinography. Animals were killed 4 and 8 weeks after cell transplantation for histological, immunological, molecular, and transcriptomic analyses of the retina.

Results

Transplanted RPCs significantly improved vision and retinal thickness as well as function in rd12 mice. pMSCs and RPCs homed to distinct retinal layers. pMSCs homed to the retinal pigment epithelium, and RPCs migrated to the neural layers of the retina, where they improved the thickness of the respective layers and expressed cell-specific markers. RPCs induced anti-inflammatory and neuroprotective responses as well as upregulated the expression of genes involved in neurogenesis. The transcriptomic analysis showed that RPCs promoted neurogenesis and functional recovery of the retina through inhibition of BMP and activation of JAK/STAT and MAPK signaling pathways.

Conclusions

Our study demonstrated that RPCs countered inflammation, provided retinal protection, and promoted neurogenesis resulting in improved retinal structure and physiological function in rd12 mice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02828-w.

Effects of Adipose-Derived Stem Cells and Their Conditioned Medium in a Human Ex Vivo Wound Model

Adult stem cells have been extensively investigated for tissue repair therapies. Adipose-derived stem cells (ASCs) were shown to improve wound healing by promoting re-epithelialization and vascularization as well as modulating the inflammatory immune response. In this study, we used ex vivo human skin cultured in a six-well plate with trans-well inserts as a model for superficial wounds. Standardized wounds were created and treated with allogeneic ASCs, ASCs conditioned medium (ASC-CM), or cell culture medium (DMEM) supplemented with fetal calf serum (FCS). Skin viability (XTT test), histology (hematoxylin and eosin, H and E), β-catenin expression as well as inflammatory mediators and growth factors were monitored over 12 days of skin culture. We observed only a moderate time-dependent decrease in skin metabolic activity while skin morphology was preserved, and re-epithelialization occurred at the wound edges. An increase in β-catenin expression was observed in the newly formed epithelia, especially in the samples treated with ASC-CM. In general, increased growth factors and inflammatory mediators, e.g., hepatocytes growth factor (HGF), platelet-derived growth factor subunit AA (PDGF-AA), IL-1α, IL-7, TNF-α, and IL-10, were observed over the incubation time. Interestingly, different expression profiles were observed for the different treatments. Samples treated with ASC-CM significantly increased the levels of inflammatory cytokines and PDGF-AA with respect to control, whereas the treatment with ASCs in DMEM with 10% FCS resulted in significantly increased levels of fibroblast growth factor-basic (FGF-basic) and moderate increases of immunomodulatory cytokines. These results confirm that the wound microenvironment can influence the type of mediators secreted by ASCs and the mode as to how they improve the wound healing process. Comparative investigations with pre-activated ASCs will elucidate further aspects of the wound healing mechanism and improve the protocols of ACS application.

Sources, Characteristics, and Therapeutic Applications of Mesenchymal Cells in Tissue Engineering

Tissue engineering (TE) is a therapeutic option within regenerative medicine that allows to mimic the original cell environment and functional organization of the cell types necessary for the recovery or regeneration of damaged tissue using cell sources, scaffolds, and bioreactors. Among the cell sources, the utilization of mesenchymal cells (MSCs) has gained great interest because these multipotent cells are capable of differentiating into diverse tissues, in addition to their self-renewal capacity to maintain their cell population, thus representing a therapeutic alternative for those diseases that can only be controlled with palliative treatments. This review aimed to summarize the state of the art of the main sources of MSCs as well as particular characteristics of each subtype and applications of MSCs in TE in seven different areas (neural, osseous, epithelial, cartilage, osteochondral, muscle, and cardiac) with a systemic revision of advances made in the last 10 years. It was observed that bone marrow-derived MSCs are the principal type of MSCs used in TE, and the most commonly employed techniques for MSCs characterization are immunodetection techniques. Moreover, the utilization of natural biomaterials is higher (41.96%) than that of synthetic biomaterials (18.75%) for the construction of the scaffolds in which cells are seeded. Further, this review shows alternatives of MSCs derived from other tissues and diverse strategies that can improve this area of regenerative medicine.

MicroRNA-30a contributes to pre-eclampsia through regulating the proliferation, apoptosis, and angiogenesis modulation potential of mesenchymal stem cells by targeting AVEN

Pre-eclampsia (PE) is a pregnancy-associated disease related to an unprecedented hypertension attack. Mesenchymal stem cells (MSCs) play a crucial role in PE pathology. . Our research was designed to illustrate the functions of microRNA-30a (miR-30a) in proliferation, apoptosis, and the potential of regulating angiogenesis in MSCs, and to analyze its potential molecular mechanisms. TargetScan software and the luciferase reporter assay were used to forecast and verify the relationship between miR-30a and AVEN. MiR-30a and AVEN expression in the decidual tissue and decidua (d)MSCs of healthy pregnant women and PE patients were assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell proliferation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT), flow cytometry, and transwell assays were used to evaluate cell proliferation, growth, the cell cycle, apoptosis, and migration. Furthermore, the tube formation ability was evaluated using the human umbilical vein endothelial cell (HUVEC) tube formation assay. AVEN is the target gene of miR-30a. MiR-30a was upregulated in decidual tissues and dMSCs of PE patients. However, AVEN was weakly expressed, and AVEN expression was negatively related to miR-30a levels in decidual tissues and dMSCs of PE patients. Compared to the mimic control group, upregulation of miR-30a inhibited dMSC proliferation and cell growth, promoted G0/G1 phase arrest, and induced apoptosis. Furthermore, the miR-30a mimic transfected dMSC culture supernatant suppressed HTR-8/SVneo cell migration ability and HUVEC tube formation ability. However, AVEN reversed these changes. In conclusion, miR-30a/AVEN may serve as a new axis for PE treatment.

Mesenchymal Stromal Cells in Ischemic Brain Injury

Ischemic brain injury represents a major cause of death worldwide with limited treatment options with a narrow therapeutic window. Accordingly, novel treatments that extend the treatment from the early neuroprotective stage to the late regenerative phase may accommodate a much larger number of stroke patients. To this end, stem cell-based regenerative therapies may address this unmet clinical need. Several stem cell therapies have been tested as potentially exhibiting the capacity to regenerate the stroke brain. Based on the long track record and safety profile of transplantable stem cells for hematologic diseases, bone marrow-derived mesenchymal stromal cells or mesenchymal stromal cells have been widely tested in stroke animal models and have reached clinical trials. However, despite the translational promise of MSCs, probing cell function remains to be fully elucidated. Recognizing the multi-pronged cell death and survival processes that accompany stroke, here we review the literature on MSC definition, characterization, and mechanism of action in an effort to gain a better understanding towards optimizing its applications and functional outcomes in stroke.

The functions of clusterin in renal mesenchymal stromal cells: Promotion of cell growth and regulation of macrophage activation

Clusterin (CLU) increases resistance to renal ischemia-reperfusion injury and promotes renal tissue repair. However, the mechanisms underlying of the renal protection of CLU remain unknown. Mesenchymal stromal cells (MSCs) may contribute to kidney cell turnover and injury repair. This study investigated the in vitro functions of CLU in kidney mesenchymal stromal cells (KMSCs). KMSCs were grown in plastic culture plates. Cell surface markers, apoptosis and phagocytosis were determined by flow cytometry, and CLU protein by Western blot. There were no differences in the expression of MSC markers (positive: CD133, Sca-1, CD44, CD117 and NG2, and negative: CD34, CD45, CD163, CD41, CD276, CD138, CD79a, CD146 and CD140b) and in the trilineage differentiation to chondrocytes, adipocytes and osteocytes between wild type (WT) and CLU knockout (KO) KMSCs. CLU was expressed intracellularly and secreted by WT KMSCs, and it was up-regulated by hypoxia. CLU did not prevent hypoxia-induced cell apoptosis but promoted cell growth in KMSC cultures. Furthermore, incubation with CLU-containing culture medium from WT KMSCs increased CD206 expression and phagocytic capacity of macrophages. In conclusion, our data for the first time demonstrate the function of CLU in the promotion of KMSCs proliferation, and it may be required for KMSCs-regulated macrophage M2 polarization and phagocytic activity.

Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells and Their Contribution to Angiogenic Processes in Tissue Regeneration

Mesenchymal stem/stromal cells (MSCs) are widely described in the context of their regenerative and immunomodulatory activity. MSCs are isolated from various tissues and organs. The most frequently described sources are bone marrow and adipose tissue. As stem cells, MSCs are able to differentiate into other cell lineages, but they are usually reported with respect to their paracrine potential. In this review, we focus on MSCs derived from adipose tissue (AT-MSCs) and their secretome in regeneration processes. Special attention is given to the contribution of AT-MSCs and their derivatives to angiogenic processes described mainly in the context of angiogenic dysfunction. Finally, we present clinical trials registered to date that concern the application of AT-MSCs and their secretome in various medical conditions.

NOD2 is involved in regulating odontogenic differentiation of DPSCs suppressed by MDP through NF-κB/p65 signaling

Dental pulp stem cells (DPSCs) are well known for their capable of both self-renewal and multilineage differentiation. Dental tissue diseases, include caries, are often accompanied by inflammatory microenvironment, and muramyl dipeptide (MDP) is involved in the inflammatory stimuli to influence the differentiation of DPSCs. Nucleotide-binding oligomerization domain 2 (NOD2), a member of the cytosolic Nod-like receptor (NLR) family, plays a key role in inflammatory homeostasis regulation, but the role of NOD2 in DPSCs differentiation under inflammatory is still unclear. In this study, we identified that MDP suppressed odontogenic differentiation of DPSCs via NOD2/ NF-κB/p65 signaling pathway. Alizarin red staining and ALP activity showed the odontogenic differentiation was suppressed by MDP in a concentration-dependent manner, and the expression of dentin differentiation marker protein dentin matrix protein 1 (DMP-1) and dentin Sialophosphoprotein (DSPP) also indicated the same results. The expression of NOD2 increased gradually with the concentration of MDP as well as the phosphorylation and nuclear translocation of p65, which meant NF-κB signaling pathway was activated. Further, the interference of NOD2 inhibited the phosphorylation and nuclear translocation of p65 and reversed the MDP-mediated decrease of odontoblast differentiation of DPSCs. Our study showed that MDP can inhibit the odontoblast differentiation of DPSCs in a concentration-dependent manner. The NF-κB signaling pathway was activated by increasing expression of NOD2. Interference of NOD2 reversed the negative ability odontoblast differentiation of DPSCs in the inflammatory environment. Our study might provide a theoretical basis for the clinical treatment for dentinogenesis of DPSCs.