Mesenchymal stem cells and their microenvironment

Beyond antibiotics: mesenchymal stem cells and bacteriophages-new approaches to combat bacterial resistance in wound infections

Wound management is a major global health problem. With the rising incidence of diabetic wounds, accidents, and other injuries, the demand for prompt wound treatment has become increasingly critical. Millions of people suffer from serious, large wounds resulting from major accidents, surgeries, and wars. These wounds require considerable time to heal and are susceptible to infection. Furthermore, chronic wounds, particularly in elderly and diabetic patients, often require frequent medical interventions to prevent complications. Consequently, wound management imposes a significant economic burden worldwide. The complications arising from wound infections can vary from localized issues to systemic effects. The most severe local complication of wound infection is the non-healing, which results from the disruption of the wound-healing process. This often leads to significant pain, discomfort, and psychological trauma for the patient. Systemic complications may include cellulitis, osteomyelitis, and septicemia. Mesenchymal stem cells are characterized by their high capacity for division, making them suitable candidates for the treatment of tissue damage. Additionally, they produce antimicrobial peptides and various cytokines, which enhance their antimicrobial activity. Evidence shows that phages are effective in treating wound-related infections, and phage therapy has proven to be highly effective for patients when administered correctly. The purpose of this article is to explore the use of bacteriophages and mesenchymal stem cells in wound healing and infection management.

Stem cells and bio scaffolds for the treatment of cardiovascular diseases: new insights

Mortality and morbidity from cardiovascular diseases are common worldwide. In order to improve survival and quality of life for this patient population, extensive efforts are being made to establish effective therapeutic modalities. New treatment options are needed, it seems. In addition to treating cardiovascular diseases, cell therapy is one of the most promising medical platforms. One of the most effective therapeutic approaches in this area is stem cell therapy. In stem cell biology, multipotent stem cells and pluripotent stem cells are divided into two types. There is evidence that stem cell therapy could be used as a therapeutic approach for cardiovascular diseases based on multiple lines of evidence. The effectiveness of stem cell therapies in humans has been studied in several clinical trials. In spite of the challenges associated with stem cell therapy, it appears that resolving them may lead to stem cells being used in cardiovascular disease patients. This may be an effective therapeutic approach. By mounting these stem cells on biological scaffolds, their effect can be enhanced.

Neutrophils suppress osteogenic differentiation of Gli1+ stem cells via neutrophil extracellular traps and contribute to bone loss in periodontitis

Periodontitis is a severe and chronic oral inflammatory disease that leads to the progressive and irreversible destruction of periodontal tissues, ultimately resulting in tooth loss. Among the immune cell subtypes involved, neutrophils play a crucial role in the initiation and progression of periodontitis. Mesenchymal stem cells (MSCs) are essential components of periodontal tissue, contributing to tissue development, homeostasis, and regeneration. Recent studies have demonstrated that neutrophils significantly affect the function of MSCs by changing the inflammatory environment. However, the specific effects of neutrophils on periodontal MSCs during periodontitis remain unclear, highlighting a gap in our understanding of the disease mechanisms. In this study, we utilized the Gli1-CreERT2;mT/mG transgenic mouse model to specifically mark Gli1+ cells, a critical and representative subset of MSCs in the periodontal tissues responsible for maintaining tissue homeostasis. We reveal that neutrophils inhibit the osteogenic differentiation of Gli1+ cells and exacerbate alveolar bone destruction by secreting neutrophil extracellular traps (NETs), which induce endoplasmic reticulum stress in Gli1+ cells. These findings highlight the pivotal impact of neutrophils on distinct subpopulations of periodontal MSCs in the pathogenesis of periodontitis, offering valuable insights into the underlying mechanisms of the disease and suggesting potential future therapeutic strategies aimed at modulating the interactions between neutrophils and MSCs.

Metabolic dysregulation in myelodysplastic neoplasm: impact on pathogenesis and potential therapeutic targets

Despite significant advancements in the research of the pathogenesis mechanisms of Myelodysplastic Neoplasm (MDS) in recent years, there are still many gaps to fill. The advancement of metabolomics studies has led to a research booming in clarifying the impact of metabolic abnormalities during the pathogenesis of MDS. The present review primarily focuses on the dysregulated metabolic pathways, exploring the influences on the pathogenesis of MDS and their roles during the course of the disease. Furthermore, we discuss the potential of relevant metabolic pathways as therapeutic targets, along with the latest metabolic-related treatment drugs and approaches.

Mesenchymal Stem/Stromal cells in solid tumor Microenvironment: Orchestrating NK cell remodeling and therapeutic insights

Mesenchymal stem/stromal cells (MSCs), originating from normal tissues, possess the capacity to home to tumor sites and differentiate into tumor-associated MSCs (TA-MSCs), which are instrumental in shaping an immunosuppressive milieu within tumors. Natural killer (NK) cells, integral to the innate immune system, are endowed with the ability to eradicate target cells autonomously, serving as an immediate defense against neoplastic growths. Nonetheless, within the tumor microenvironment (TME), NK cells often exhibit a decline in both their numerical presence and functionality. TA-MSCs have been shown to exert profound inhibitory effects on the functions of tumor-infiltrating immune cells, notably NK cells. Understanding the mechanisms by which TA-MSCs contribute to NK cell dysfunction is critical for the advancement of immune surveillance and the enhancement of tumoricidal responses. This review summarizes existing literature on NK cell modulation by TA-MSCs within the TME and proposes innovative strategies to augment antitumor immunity.

Autologous Microfragmented Adipose Tissue Injection in Refractory Complex Crohn's Perianal Fistulas: Long-Term Results at 6.7 Years Mean Follow-up

BACKGROUND

Nowadays, there is a clear need for new viable therapeutic options to face complex perianal Crohn's disease (PCD). Results of our previous pilot study demonstrated the efficacy and safety of local injection of autologous microfragmented adipose tissue (MFat) in this setting. This study aims to evaluate the long-term follow-up results in the same cohort of patients.

METHODS

Data on clinical and radiological remission and surgical recurrence rates were prospectively collected on the 15 patients with complex fistulizing PCD refractory to combined bio-surgical therapy, originally treated with local MFat injection, with a mean 6.7 years follow-up.

RESULTS

In our previous study, at 24-week follow-up, combined remission was reported in 66.7% of patients, while clinical remission was achieved in 93% of cases. At a 6.7-year follow-up, 9 of the 10 healed patients maintained remission. The patient with recurrence was successfully reoperated. Three out of 5 patients who failed primary combined remission were retreated, with 2 obtaining combined remission and 1 failing. One patient refused any subsequent treatment due to good quality of life. The last patient presented delayed healing at a 1-year follow-up. Overall success rate after rescue therapy at the final follow-up reached 86.6%. Safety was maintained throughout all follow-up periods.

CONCLUSIONS

This is the longest follow-up published trial on MFat injection for PCD. Our results show that patients who achieved closure in the first 24 weeks sustained response at long-term evaluation. In addition, there may be a rationale in repeating treatment as rescue therapy in not responding to patients.

Biological strategies in rotator cuff repair: a clinical application and molecular background

Conventional repair of rotator cuff tears bears a variable but significant risk of incomplete healing. Biological therapies that accompany surgical rotator cuff repair include platelet-rich plasma, stem cells of different origins, and biological scaffolds. Biological therapies facilitate the regeneration of the correct microarchitecture of the tendon attachment to the bone and reduce failures after surgical rotator cuff repair.

Innovative hydrogel-based therapies for ischemia-reperfusion injury： bridging the gap between pathophysiology and treatment

Ischemia-reperfusion injury (IRI) commonly occurs in clinical settings, particularly in medical practices such as organ transplantation, cardiopulmonary resuscitation, and recovery from acute trauma, posing substantial challenges in clinical therapies. Current systemic therapies for IRI are limited by poor drug targeting, short efficacy, and significant side effects. Owing to their exceptional biocompatibility, biodegradability, excellent mechanical properties, targeting capabilities, controlled release potential, and properties mimicking the extracellular matrix (ECM), hydrogels not only serve as superior platforms for therapeutic substance delivery and retention, but also facilitate bioenvironment cultivation and cell recruitment, demonstrating significant potential in IRI treatment. This review explores the pathological processes of IRI and discusses the roles and therapeutic outcomes of various hydrogel systems. By categorizing hydrogel systems into depots delivering therapeutic agents, scaffolds encapsulating mesenchymal stem cells (MSCs), and ECM-mimicking hydrogels, this article emphasizes the selection of polymers and therapeutic substances, and details special crosslinking mechanisms and physicochemical properties, as well as summarizes the application of hydrogel systems for IRI treatment. Furthermore, it evaluates the limitations of current hydrogel treatments and suggests directions for future clinical applications.

Enhancing Fracture Healing with 3D Bioprinted Hif1a-Overexpressing BMSCs Hydrogel: A Novel Approach to Accelerated Bone Repair

Addressing the urgent need for effective fracture treatments, this study investigates the efficacy of a 3D bioprinted biomimetic hydrogel, enriched with bone marrow mesenchymal stem cells (BMSCs) and targeted hypoxia-inducible factor 1 alpha (Hif1a) gene activation, in enhancing fracture healing. A photocross-linkable bioink, gelatin methacryloyl bone matrix anhydride (GBMA) is developed, and selected its 5% concentration for bioink formulation. Rat BMSCs are isolated and combined with GBMA to create the GBMA@BMSCs bioink. This bioink is then used in 3D bioprinting to fabricate a hydrogel for application in a rat femoral fracture model. Through transcriptome sequencing, WGCNA, and Venn analysis, the hypoxia-inducible factor Hif1a is identified as a critical gene in the fracture healing process. In vitro studies showed that Hif1a promoted BMSC proliferation, chondrogenic differentiation, and cartilage matrix stability. The in vivo application of the GBMA@BMSCs hydrogel with Hif1a overexpression significantly accelerated fracture healing, evidenced by early and enhanced cartilage callus formation. The study demonstrates that 3D bioprinting of GBMA@BMSCs hydrogel, particularly with Hif1a-enhanced BMSCs, offers a promising approach for rapid and effective fracture repair.

Engineering ADSCs by manipulating YAP for lymphedema treatment in a mouse tail model

Secondary lymphedema is a chronic disease associated with deformity of limbs and dysfunction; however, conventional therapies are not curative. Adipose-derived stem cells (ADSCs) based therapy is a promising way, but a single transplantation of ADSCs has limited efficacy. In this study, ADSCs were engineered in vitro and then transplanted into the site of lymphedema. Yes-associated protein (YAP), a crucial regulator of Hippo pathway, plays an important role in regulating stem cell functions. We examined the YAP expression in a mouse tail lymphedema model, and found that transplanted ADSCs exhibited high expression level of YAP and a large number of YAP positive cells existed in lymphedema environment. In vitro, the downregulation of YAP in ADSCs resulted in higher expression levels of genes related to lymphangiogenesis such as Lyve-1, VEGFR-3 and Prox-1. In vivo, YAP-engineered ADSCs generated abundant VEGFR-3-positive lymphatic vessels and significantly improved subcutaneous fibrosis. These results indicated that the transplantation of pre-engineered ADSCs by manipulating YAP is a promising strategy for lymphatic reconstruction.

Therapeutic effects of extracellular vesicles derived from mesenchymal stem cells primed with disease-conditioned-immune cells in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is an incurable chronic autoimmune disease of unknown etiology. Therefore, the development of new treatments is urgently needed. This study aimed to investigate the therapeutic effects of extracellular vesicles (EV) derived from immortalized mesenchymal stem cells (iMSCs) primed with conditioned media obtained from disease-conditioned immune cells (CM-EV) and iMSC-derived EV (ASC-EV) in a murine model of SLE.

METHODS

Female NZB/W F1 mice were divided into the control (C, n = 15), ASC-EV (E, n = 15), and CM-EV (CM, n = 15) groups. Mice in the C, E, and CM groups were intravenously administered saline, ASC-EV, and CM-EV, respectively, once weekly from 6 to 42 weeks of age.

RESULTS

Compared to the ASC-EV, the CM-EV showed a significant increase in TGF-β1 production and miR-155-5p and miR-142-3p expression. CM-EV treatment increased survival, decreased anti-dsDNA antibody levels, and ameliorated renal histopathology. Although ASC-EV treatment significantly reduced the incidence of severe proteinuria and improved renal histopathology, it did not significantly improve survival rate. ASC-EV or CM-EV treatment significantly decreased the proportion of pro-inflammatory macrophages (CD11c + CD206-; M1) and M1:M2 ratio. Additionally, CM-EV treatment significantly increased the expression of anti-inflammatory macrophages (CD11c-CD206 + ; M2). Moreover, CM-EV treatment significantly decreased the expression of lupus-specific miRNAs (miR-182-5p and miR-183-5p) in the spleen.

CONCLUSIONS

EV derived from iMSCs primed with conditioned media obtained from disease-conditioned immune cells exert immunomodulatory effects and ameliorate SLE in a murine model.

Mesenchymal stem cells alleviate inflammatory responses through regulation of T-cell subsets

Immune-mediated inflammatory disease (IMID) is a complex disorder characterized by excessive immune responses involving T cells and their subsets, leading to direct tissue damage. T cells can be broadly categorized into CD4+ T cells and CD8+ T cells. CD4+ T cells are composed of several subsets, including T helper (Th)1, Th2, Th9, Th17, Th22, follicular helper T cells (Tfhs), and regulatory T cells (Tregs), while effector CD8+ T cells consist mainly of cytotoxic T cells (CTLs). Current therapies for IMID are ineffective, prompting exploration into mesenchymal stem cells (MSCs) as a promising clinical treatment due to their immunomodulatory effects and self-renewal potential. Recent studies have shown that MSCs can suppress T cells through direct cell-to-cell contact or secretion of soluble cytokines. Nevertheless, the precise effects of MSCs on T cell subsets remain inadequately defined. In this review, we summarize the most recent studies that have examined how MSCs modulate one or more effector T-cell subsets and the mechanisms behind these modifications in vitro and several mouse models of clinical inflammation. This also provides theoretical support and novel insights into the efficacy of clinical treatments involving MSCs. However, the efficacy of MSC therapies in clinical models of inflammation varies, showing effective remission in most cases, but also with exacerbation of T-cell-mediated inflammatory damage in some instances.

The Potential of Mesenchymal Stem/Stromal Cells in Diabetic Wounds and Future Directions for Research and Therapy-Is It Time for Use in Everyday Practice?

The treatment of diabetic wounds is impaired by the intricate nature of diabetes and its associated complications, necessitating novel strategies. The utilization of mesenchymal stem/stromal cells (MSCs) as a therapeutic modality for chronic and recalcitrant wounds in diabetic patients is an active area of investigation aimed at enhancing its therapeutic potential covering tissue regeneration. The threat posed to the patient and their environment by the presence of a diabetic foot ulcer (DFU) is so significant that any additional therapeutic approach that opens new pathways to halt the progression of local changes, which subsequently lead to a generalized inflammatory process, offers a chance to reduce the risk of amputation or even death. This article explores the potential of MSCs in diabetic foot ulcer treatment, examining their mechanisms of action, clinical application challenges, and future directions for research and therapy.

Hypoxia-Preconditioned Human Umbilical Cord Mesenchymal Stem Cells Transplantation Ameliorates Inflammation and Bone Regeneration in Peri-Implantitis Rat Model

OBJECTIVE

 The failure of dental implant treatments is predominantly attributed to peri-implantitis, which entails chronic inflammation within the peri-implant tissue, ultimately leading to tissue degradation. Addressing this condition, human umbilical cord mesenchymal stem cell (hUCMSC) transplantation serves as a regenerative therapy; however, concerns regarding the viability and efficacy of transplanted cells in inflamed regions persist. Hypoxic preconditioning of hUCMSCs has emerged as a potential strategy for augmenting their regenerative and immunomodulatory capacities. This study aimed to evaluate the expression of inflammatory (tumor necrosis factor [TNF]-α) and bone regenerative biomarkers (nuclear factor of activated T-cell [NFATc1], osteocalcin, collagen type I alpha 1 [COL1α1]) within peri-implantitis models subsequent to the transplantation of hypoxia-preconditioned hUCMSCs.

MATERIALS AND METHODS

 Peri-implantitis models were established through the insertion of implants into the femur bone of 42 Wistar strain Rattus norvegicus, followed by intrasocket injection of lipopolysaccharide. The experimental animals were categorized into three groups (control, normoxia, and hypoxia) and underwent observation on days 14 and 28. The expression levels of TNF-α, NFATc1, COL1α1, and osteocalcin were evaluated using immunohistochemical staining, and the resulting data were subjected to one-way analysis of variance analysis (p < 0.05).

RESULTS

 Transplantation of hypoxia-preconditioned hUCMSCs significantly ameliorated inflammation and osteoclastogenesis, as evidenced by significant reductions in TNF-α and NFATc1 expression compared with the control group. Furthermore, hypoxic preconditioning of hUCMSCs demonstrated a significant elevation in the expression of osteocalcin and COL1α1 relative to the control group.

CONCLUSION

 The transplantation of hypoxia-preconditioned hUCMSCs exhibited a capacity to ameliorate inflammation and enhance bone regenerative processes in peri-implantitis rat models.

Mitochondrial transfer from mesenchymal stem cells: Mechanisms and functions

Mesenchymal stem cells based therapy has been used in clinic for almost 20 years and has shown encouraging effects in treating a wide range of diseases. However, the underlying mechanism is far more complicated than it was previously assumed. Mitochondria transfer is one way that recently found to be employed by mesenchymal stem cells to exert its biological effects. As one way of exchanging mitochondrial components, mitochondria transfer determines both mesenchymal stem cells and recipient cell fates. In this review, we describe the factors that contribute to MSCs-MT. Then, the routes and mechanisms of MSCs-MT are summarized to provide a theoretical basis for MSCs therapy. Besides, the advantages and disadvantages of MSCs-MT in clinical application are analyzed.

Roles of Microenvironment on Mesenchymal Stem Cells Therapy for Osteoarthritis

Osteoarthritis (OA) induced microenvironmental alterations are a common and unavoidable phenomenon that greatly exacerbate the pathologic process of OA. Imbalances in the synthesis and degradation of cartilage extracellular matrix (ECM) have been reported to be associated with an adverse microenvironment. Stem cell therapy is a promising treatment for OA, and mesenchymal stem cells (MSCs) are the main cell sources for this therapy. With multispectral differentiation and immunomodulation, MSCs can effectively regulate the microenvironment of articular cartilage, ameliorate inflammation, promote regeneration of damaged cartilage, and ultimately alleviate OA symptoms. However, the efficacy of MSCs in the treatment of OA is greatly influenced by articular cavity microenvironments. This article reviews the five microenvironments of OA articular cavity, including inflammatory microenvironment, senescence microenvironment, hypoxic microenvironment, high glucose microenvironment and high lipid environment, focus on the positive and negative effects of OA microenvironments on the fate of MSCs. In this regard, we emphasize the mechanisms of the current use of MSCs in OA treatment, as well as its limitations and challenges.

Exploration of N6-methyladenosine modification in ascorbic acid 2-glucoside constructed stem cell sheets

The aim of this study was to explore the mechanism of bone marrow stem cells (BMSCs) sheets constructed with different doses of Ascorbic acid 2-glucoside (AA-2G) in conjunction with N6-methyladenosine (m6A)-associated epigenetic genes analysing transcriptome sequencing data. Experimental groups of BMSCs induced by different AA-2G concentrations were set up, and the tissue structures were observed by histological staining of cell slices and scanning electron microscopy. Expression patterns of DEGs were analysed using short-time sequence expression mining software, and DEGs associated with m6A were selected for gene ontology analysis and pathway analysis. The protein-protein interaction (PPI) network of DEGs was analysed and gene functions were predicted using the search tool of the Retrieve Interacting Genes database. There were 464 up-regulated DEGs and 303 down-regulated DEGs between the control and high-dose AA-2G treatment groups, and 175 up-regulated DEGs and 37 down-regulated DEGs between the low and high-dose AA-2G treatment groups. The profile 7 exhibited a gradual increase in gene expression levels over AA-2G concentration. In contrast, profile 0 exhibited a gradual decrease in gene expression levels over AA-2G concentration. In the PPI network of m6A-related DEGs in profile 7, the cluster of metallopeptidase inhibitor 1 (Timp1), intercellular adhesion molecule 1 (Icam1), insulin-like growth factor 1 (Igf1), matrix metallopeptidase 2 (Mmp2), serpin family E member 1 (Serpine1), C-X-C motif chemokine ligand 2 (Cxcl2), galectin 3 (Lgals3) and angiopoietin-1 (Angpt1) was the top hub gene cluster. The expression of all hub genes was significantly increased after AA-2G intervention (P < 0.05), and the expression of Igf1 and Timp1 increased with increasing intervention concentration. The m6A epigenetic modifications were involved in the AA-2G-induced formation of BMSCs. Igf1, Serpine1 and Cxcl2 in DEGs were enriched for tissue repair, promotion of endothelial and epithelial proliferation and regulation of apoptosis.

HIV Modulates Osteoblast Differentiation via Upregulation of RANKL and Vitronectin

Bone loss is a prevalent characteristic among people with HIV (PWH). We focused on mesenchymal stem cells (MSCs) and osteoblasts, examining their susceptibility to different HIV strains (R5- and X4-tropic) and the subsequent effects on bone tissue homeostasis. Our findings suggest that MSCs and osteoblasts are susceptible to R5- and X4-tropic HIV but do not support productive HIV replication. HIV exposure during the osteoblast differentiation process revealed that the virus could not alter mineral and organic matrix deposition. However, the reduction in runt-related transcription factor 2 (RUNX2) transcription, the increase in the transcription of nuclear receptor activator ligand kappa B (RANKL), and the augmentation of vitronectin deposition strongly suggested that X4- and R5-HIV could affect bone homeostasis. This study highlights the HIV ability to alter MSCs' differentiation into osteoblasts, critical for maintaining bone and adipose tissue homeostasis and function.

Biological Functions of Macromolecular Protein Hydrogels in Constructing Osteogenic Microenvironment

Irreversible bone defects resulting from trauma, infection, and degenerative illnesses have emerged as a significant health concern. Structurally and functionally controllable hydrogels made by bone tissue engineering (BTE) have become promising biomaterials. Natural proteins are able to establish connections with autologous proteins through unique biologically active regions. Hydrogels based on proteins can simulate the bone microenvironment and regulate the biological behavior of stem cells in the tissue niche, making them candidates for research related to bone regeneration. This article reviews the biological functions of various natural macromolecular proteins (such as collagen, gelatin, fibrin, and silk fibroin) and highlights their special advantages as hydrogels. Then the latest research trends on cross-linking modified macromolecular protein hydrogels with improved mechanical properties and composite hydrogels loaded with exogenous micromolecular proteins have been discussed. Finally, the applications of protein hydrogels, such as 3D printed hydrogels, microspheres, and injectable hydrogels, were introduced, aiming to provide a reference for the repair of clinical bone defects.

Iron-dependent KDM4D activity controls the quiescence-activity balance of MSCs via the PI3K-Akt-Foxo1 pathway

Iron deficiency is a prevalent nutritional deficit associated with organ damage and dysfunction. Recent research increasingly associates iron deficiency with bone metabolism dysfunction, although the precise underlying mechanisms remain unclear. Some studies have proposed that iron-dependent methylation-erasing enzyme activity regulates cell proliferation and differentiation under physiological or pathological conditions. However, it remains uncertain whether iron deficiency inhibits the activation of quiescent mesenchymal stem cells (MSCs) by affecting histone demethylase activity. In our study, we identified KDM4D as a key player in the activation of quiescent MSCs. Under conditions of iron deficiency, the H3K9me3 demethylase activity of KDM4D significantly decreased. This alteration resulted in increased heterochromatin with H3K9me3 near the PIK3R3 promoter, suppressing PIK3R3 expression and subsequently inhibiting the activation of quiescent MSCs via the PI3K-Akt-Foxo1 pathway. Iron-deficient mice displayed significantly impaired bone marrow MSCs activation and decreased bone mass compared to normal mice. Modulating the PI3K-Akt-Foxo1 pathway could reverse iron deficiency-induced bone loss.

Mesenchymal stem cells in autoimmune disease: A systematic review and meta-analysis of pre-clinical studies

Mesenchymal Stem Cells (MSCs) are of interest in the clinic because of their immunomodulation capabilities, capacity to act upstream of inflammation, and ability to sense metabolic environments. In standard physiologic conditions, they play a role in maintaining the homeostasis of tissues and organs; however, there is evidence that they can contribute to some autoimmune diseases. Gaining a deeper understanding of the factors that transition MSCs from their physiological function to a pathological role in their native environment, and elucidating mechanisms that reduce their therapeutic relevance in regenerative medicine, is essential. We conducted a Systematic Review and Meta-Analysis of human MSCs in preclinical studies of autoimmune disease, evaluating 60 studies that included 845 patient samples and 571 control samples. MSCs from any tissue source were included, and the study was limited to four autoimmune diseases: multiple sclerosis, rheumatoid arthritis, systemic sclerosis, and lupus. We developed a novel Risk of Bias tool to determine study quality for in vitro studies. Using the International Society for Cell & Gene Therapy's criteria to define an MSC, most studies reported no difference in morphology, adhesion, cell surface markers, or differentiation into bone, fat, or cartilage when comparing control and autoimmune MSCs. However, there were reported differences in proliferation. Additionally, 308 biomolecules were differentially expressed, and the abilities to migrate, invade, and form capillaries were decreased. The findings from this study could help to explain the pathogenic mechanisms of autoimmune disease and potentially lead to improved MSC-based therapeutic applications.

Bioactive Materials That Promote the Homing of Endogenous Mesenchymal Stem Cells to Improve Wound Healing

Endogenous stem cell homing refers to the transport of endogenous mesenchymal stem cells (MSCs) to damaged tissue. The paradigm of using well-designed biomaterials to induce resident stem cells to home in to the injured site while coordinating their behavior and function to promote tissue regeneration is known as endogenous regenerative medicine (ERM). ERM is a promising new avenue in regenerative therapy research, and it involves the mobilizing of endogenous stem cells for homing as the principal means through which to achieve it. Comprehending how mesenchymal stem cells home in and grasp the influencing factors of mesenchymal stem cell homing is essential for the understanding and design of tissue engineering. This review summarizes the process of MSC homing, the factors influencing the homing process, analyses endogenous stem cell homing studies of interest in the field of skin tissue repair, explores the integration of endogenous homing promotion strategies with cellular therapies and details tissue engineering strategies that can be used to modulate endogenous homing of stem cells. In addition to providing more systematic theories and ideas for improved materials for endogenous tissue repair, this review provides new perspectives to explore the complex process of tissue remodeling to enhance the rational design of biomaterial scaffolds and guide tissue regeneration strategies.

The application potential of iMSCs and iMSC-EVs in diseases

The immune system, functioning as the body's "defense army", plays a role in surveillance, defense. Any disruptions in immune system can lead to the development of immune-related diseases. Extensive researches have demonstrated the crucial immunoregulatory role of mesenchymal stem cells (MSCs) in these diseases. Of particular interest is the ability to induce somatic cells under specific conditions, generating a new cell type with stem cell characteristics known as induced pluripotent stem cell (iPSC). The differentiation of iPSCs into MSCs, specifically induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs), hold promise as a potential solution to the challenges of MSCs, potentially serving as an alternative to traditional drug therapies. Moreover, the products of iMSCs, termed induced pluripotent stem cell-derived mesenchymal stem cell-derived extracellular vesicles (iMSC-EVs), may exhibit functions similar to iMSCs. With the biological advantages of EVs, they have become the focus of "cell-free therapy". Here, we provided a comprehensive summary of the biological impact of iMSCs on immune cells, explored the applications of iMSCs and iMSC-EVs in diseases, and briefly discussed the fundamental characteristics of EVs. Finally, we overviewed the current advantages and challenges associated with iMSCs and iMSC-EVs. It is our hope that this review related to iMSCs and iMSC-EVs will contribute to the development of new approaches for the treatment of diseases.

The Immunological Profile of Adipose Mesenchymal Stromal/Stem Cells after Cell Expansion and Inflammatory Priming

BACKGROUND

AT-MSCs display great immunoregulatory features, making them potential candidates for cell-based therapy. This study aimed to evaluate the "RBC lysis buffer" isolation protocol and immunological profiling of the so-obtained AT-MSCs.

METHODS

We established an immune-comparative screening of AT-MSCs throughout in vitro cell expansion (PM, P1, P2, P3, P4) and inflammatory priming regarding the expression of 28 cell-surface markers, 6 cytokines/chemokines, and 10 TLR patterns.

FINDINGS

AT-MSCs were highly expandable and sensitive to microenvironment challenges, hereby showing plasticity in distinct expression profiles. Both cell expansion and inflammation differentially modulated the expression profile of CD34, HLA-DR, CD40, CD62L, CD200 and CD155, CD252, CD54, CD58, CD106, CD274 and CD112. Inflammation resulted in a significant increase in the expression of the cytokines IL-6, IL-8, IL-1β, IL-1Ra, CCL5, and TNFα. Depending on the culture conditions, the expression of the TLR pattern was distinctively altered with TLR1-4, TLR7, and TLR10 being increased, whereas TLR6 was downregulated. Protein network and functional enrichment analysis showed that several trophic and immune responses are likely linked to these immunological changes.

CONCLUSIONS

AT-MSCs may sense and actively respond to tissue challenges by modulating distinct and specific pathways to create an appropriate immuno-reparative environment. These mechanisms need to be further characterized to identify and assess a molecular target that can enhance or impede the therapeutic ability of AT-MSCs, which therefore will help improve the quality, safety, and efficacy of the therapeutic strategy.

Atoh1 overexpression promotes Guinea pig bone marrow mesenchymal stem cells to differentiate into neural stem cell

Sensorineural hearing loss (SNHL) is a prevalent condition in otolaryngology. A key obstacle is finding effective strategies for regenerating damaged cochlear hair cells in adult animals. A practical and reliable approach has been developed to create a superior cell source for stem cell transplantation in the inner ear to treat SNHL. Atoh1 is involved in the differentiation of neurons, intestinal secretory cells, and mechanoreceptors including auditory hair cells, and thus plays an important role in neurogenesis. Lentivirus-mediated transfection of bone marrow mesenchymal stem cells (BMSCs) was utilized to achieve stable expression of the essential transcription factor Atoh1, which is crucial for developing auditory hair cells without compromising cell survival. By manipulating the induction conditions through altering the cell growth environment using anti-adherent culture, the synergistic impact of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) was effectively applied to significantly improve the differentiation efficiency of bone marrow-derived mesenchymal stem cells (BMSC) into neural stem cells (NSCs) following Atoh1 transfection, thereby reducing the induction time. The study indicated that the newly proposed transdifferentiation method effectively transformed BMSCs into NSCs in a controlled environment, presenting a potential approach for stem cell transplantation to promote hair cell regeneration.

Mesenchymal Stem Cell-Secreted Exosomes and Soluble Signals Regulate Breast Cancer Metastatic Dormancy: Current Progress and Future Outlook

Breast cancer is most common in women, and in most cases there is no evidence of spread and the primary tumor is removed, resulting in a 'cure'. However, in 10% to 30% of these women, distant metastases recur after years to decades. This is due to breast cancer cells disseminating to distant organs and lying quiescent. This is called metastatic dormancy. Dormant cells are generally resistant to chemotherapy, hormone therapy and immunotherapy as they are non-cycling and receive survival signals from their microenvironment. In this state, they are clinically irrelevant. However, risk factors, including aging and inflammation can awaken dormant cells and cause breast cancer recurrences, which may happen even more than ten years after the primary tumor removal. How these breast cancer cells remain in dormancy is being unraveled. A key element appears to be the mesenchymal stem cells in the bone marrow that have been shown to promote breast cancer metastatic dormancy in recent studies. Indirect co-culture, direct co-culture and exosome extraction were conducted to investigate the modes of signal operation. Multiple signaling molecules act in this process including both protein factors and microRNAs. We integrate these studies to summarize current findings and gaps in the field and suggest future research directions for this field.

Insights into the role of mesenchymal stem cells in cutaneous medical aesthetics: from basics to clinics

With the development of the economy and the increasing prevalence of skin problems, cutaneous medical aesthetics are gaining more and more attention. Skin disorders like poor wound healing, aging, and pigmentation have an impact not only on appearance but also on patients with physical and psychological issues, and even impose a significant financial burden on families and society. However, due to the complexities of its occurrence, present treatment options cannot produce optimal outcomes, indicating a dire need for new and effective treatments. Mesenchymal stem cells (MSCs) and their secretomics treatment is a new regenerative medicine therapy that promotes and regulates endogenous stem cell populations and/or replenishes cell pools to achieve tissue homeostasis and regeneration. It has demonstrated remarkable advantages in several skin-related in vivo and in vitro investigations, aiding in the improvement of skin conditions and the promotion of skin aesthetics. As a result, this review gives a complete description of recent scientific breakthroughs in MSCs for skin aesthetics and the limitations of their clinical applications, aiming to provide new ideas for future research and clinical transformation.

The impact of exosomes derived from B-cell acute lymphoblastic leukemia as a growth factor on bone marrow mesenchymal stromal cells

Background The incidence of various types of cancers, including leukemia, is on the rise and many challenges in both drug resistance and complications related to chemotherapy appeared. Recently, the development and application of extracellular vesicles (EV) such as exosomes in the management of cancers, especially leukemia, holds great significance. In this article, we extracted exosomes from NALM6 cells and assessed their regulatory effects on proliferation and apoptosis in mesenchymal stem cells (MSCs). Method and result We first verified the exosomes using various techniques, including flow cytometry, transient electron microscopy, dynamic light scattering (DLS), and BCA protein assay. Then MTT analysis and flowcytometry (apoptosis and cell cycle assay) besides gene expressions were employed to determine the state of MSC proliferations. The results indicated that exosome-specific pan markers like CD9, CD63, and CD81 were present. Through DLS, we found out that the mean size of the exosomes was 89.68 nm. The protein content was determined to be 956.292 µg/ml. Analysis of MTT, flow cytometry (cell cycle and apoptosis assay), and RT-qPCR showed that in the dose of 50 µg/ml the proliferation of MSCs was increased significantly (p-value < 0.05). Conclusion All these data showed that exosomes use several signaling pathways to increase the MSCs' proliferation and drug resistance, ultimately leading to high mortalities and morbidities of acute lymphoblastic leukemia.

Mesenchymal Stem Cells and Purinergic Signaling in Autism Spectrum Disorder: Bridging the Gap between Cell-Based Strategies and Neuro-Immune Modulation

The prevalence of autism spectrum disorder (ASD) is still increasing, which means that this neurodevelopmental lifelong pathology requires special scientific attention and efforts focused on developing novel therapeutic approaches. It has become increasingly evident that neuroinflammation and dysregulation of neuro-immune cross-talk are specific hallmarks of ASD, offering the possibility to treat these disorders by factors modulating neuro-immunological interactions. Mesenchymal stem cell-based therapy has already been postulated as one of the therapeutic approaches for ASD; however, less is known about the molecular mechanisms of stem cell influence. One of the possibilities, although still underestimated, is the paracrine purinergic activity of MSCs, by which stem cells ameliorate inflammatory reactions. Modulation of adenosine signaling may help restore neurotransmitter balance, reduce neuroinflammation, and improve overall brain function in individuals with ASD. In our review article, we present a novel insight into purinergic signaling, including but not limited to the adenosinergic pathway and its role in neuroinflammation and neuro-immune cross-talk modulation. We anticipate that by achieving a greater understanding of the purinergic signaling contribution to ASD and related disorders, novel therapeutic strategies may be devised for patients with autism in the near future.

Homeostasis and evolution in relation to regeneration and repair

Homeostasis constitutes a key concept in physiology and refers to self-regulating processes that maintain internal stability when adjusting to changing external conditions. It diminishes internal entropy constituting a driving force behind evolution. Natural selection might act on homeostatic regulatory mechanisms and control mechanisms including homeodynamics, allostasis, hormesis and homeorhesis, where different stable stationary states are reached. Regeneration is under homeostatic control through hormesis. Damage to tissues initiates a response to restore the impaired equilibrium caused by mild stress using cell proliferation, cell differentiation and cell death to recover structure and function. Repair is a homeorhetic change leading to a new stable stationary state with decreased functionality and fibrotic scarring without reconstruction of the 3-D pattern. Mechanisms determining entrance of the tissue or organ to regeneration or repair include the balance between innate and adaptive immune cells in relation to cell plasticity and stromal stem cell responses, and redox balance. The regenerative and reparative capacities vary in different species, distinct tissues and organs, and at different stages of development including ageing. Many cell signals and pathways play crucial roles determining regeneration or repair by regulating protein synthesis, cellular growth, inflammation, proliferation, autophagy, lysosomal function, metabolism and metalloproteinase cell signalling. Attempts to favour the entrance of damaged tissues to regeneration in those with low proliferative rates have been made; however, there are evolutionary constraint mechanisms leading to poor proliferation of stem cells in unfavourable environments or tumour development. More research is required to better understand the regulatory processes of these mechanisms.

Harvesting methods of umbilical cord-derived mesenchymal stem cells from culture modulate cell properties and functions

Introduction

Human umbilical cord-derived mesenchymal stem cells (UC-MSCs) are promising candidates for stem cell therapy. Various methods such as enzymatic treatment, cell scraping, and temperature reduction using temperature-responsive cell culture dishes have been employed to culture and harvest UC-MSCs. However, the effects of different harvesting methods on cell properties and functions in vitro remain unclear. In this study, we investigated the properties and functions of UC-MSC using various cell-harvesting methods.

Methods

UC-MSC suspensions were prepared using treatments with various enzymes, cell scraping, and temperature reduction in temperature-responsive cell culture dishes. UC-MSC sheets were prepared in a temperature-responsive cell culture dish. The properties and functions of the UC-MSC suspensions and sheets were assessed according to Annexin V staining, lactate dehydrogenase (LDH) assay, re-adhesion behavior, and cytokine secretion analysis via enzyme-linked immunosorbent assay.

Results

Annexin V staining revealed that accutase induced elevated UC-MSC apoptosis. Physical scraping using a cell scraper induced a relatively high LDH release due to damaged cell membranes. Dispase exhibited relatively low adhesion from initial incubation until 3 h. UC-MSC sheets exhibited rapid re-adhesion at 15 min and cell migration at 6 h. UC-MSC sheets expressed higher levels of cytokines such as HGF, TGF-β1, IL-10, and IL-6 than did UC-MSCs in suspension.

Conclusions

The choice of enzyme and physical scraping methods for harvesting UC-MSCs significantly influenced their activity and function. Thus, selecting appropriate cell-harvesting methods is important for successful stem cell therapy.

Horizontal mitochondrial transfer as a novel bioenergetic tool for mesenchymal stromal/stem cells: molecular mechanisms and therapeutic potential in a variety of diseases

Intercellular mitochondrial transfer (MT) is a newly discovered form of cell-to-cell signalling involving the active incorporation of healthy mitochondria into stressed/injured recipient cells, contributing to the restoration of bioenergetic profile and cell viability, reduction of inflammatory processes and normalisation of calcium dynamics. Recent evidence has shown that MT can occur through multiple cellular structures and mechanisms: tunneling nanotubes (TNTs), via gap junctions (GJs), mediated by extracellular vesicles (EVs) and other mechanisms (cell fusion, mitochondrial extrusion and migrasome-mediated mitocytosis) and in different contexts, such as under physiological (tissue homeostasis and stemness maintenance) and pathological conditions (hypoxia, inflammation and cancer). As Mesenchimal Stromal/ Stem Cells (MSC)-mediated MT has emerged as a critical regulatory and restorative mechanism for cell and tissue regeneration and damage repair in recent years, its potential in stem cell therapy has received increasing attention. In particular, the potential therapeutic role of MSCs has been reported in several articles, suggesting that MSCs can enhance tissue repair after injury via MT and membrane vesicle release. For these reasons, in this review, we will discuss the different mechanisms of MSCs-mediated MT and therapeutic effects on different diseases such as neuronal, ischaemic, vascular and pulmonary diseases. Therefore, understanding the molecular and cellular mechanisms of MT and demonstrating its efficacy could be an important milestone that lays the foundation for future clinical trials.

Mesenchymal stem cells-macrophages crosstalk and myeloid malignancy

As major components of the tumor microenvironment, both mesenchymal stem cells (MSCs) and macrophages can be remodelled and exhibit different phenotypes and functions during tumor initiation and progression. In recent years, increasing evidence has shown that tumor-associated macrophages (TAMs) play a crucial role in the growth, metastasis, and chemotherapy resistance of hematological malignancies, and are associated with poor prognosis. Consequently, TAMs have emerged as promising therapeutic targets. Notably, MSCs exert a profound influence on modulating immune cell functions such as macrophages and granulocytes, thereby playing a crucial role in shaping the immunosuppressive microenvironment surrounding tumors. However, in hematological malignancies, the cellular and molecular mechanisms underlying the interaction between MSCs and macrophages have not been clearly elucidated. In this review, we provide an overview of the role of TAMs in various common hematological malignancies, and discuss the latest advances in understanding the interaction between MSCs and macrophages in disease progression. Additionally, potential therapeutic approaches targeting this relationship are outlined.

Hyaluronan in mesenchymal stromal cell lineage differentiation from human pluripotent stem cells: application in serum free culture

BACKGROUND

Hyaluronan (HA) is an extracellular glycosaminoglycan polysaccharide with widespread roles throughout development and in healthy and neoplastic tissues. In pluripotent stem cell culture it can support both stem cell renewal and differentiation. However, responses to HA in culture are influenced by interaction with a range of cognate factors and receptors including components of blood serum supplements, which alter results. These may contribute to variation in cell batch production yield and phenotype as well as heighten the risks of adventitious pathogen transmission in the course of cell processing for therapeutic applications. MAIN: Here we characterise differentiation of a human embryo/pluripotent stem cell derived Mesenchymal Stromal Cell (hESC/PSC-MSC)-like cell population by culture on a planar surface coated with HA in serum-free media qualified for cell production for therapy. Resulting cells met minimum criteria of the International Society for Cellular Therapy for identification as MSC by expression of. CD90, CD73, CD105, and lack of expression for CD34, CD45, CD14 and HLA-II. They were positive for other MSC associated markers (i.e.CD166, CD56, CD44, HLA 1-A) whilst negative for others (e.g. CD271, CD71, CD146). In vitro co-culture assessment of MSC associated functionality confirmed support of growth of hematopoietic progenitors and inhibition of mitogen activated proliferation of lymphocytes from umbilical cord and adult peripheral blood mononuclear cells, respectively. Co-culture with immortalized THP-1 monocyte derived macrophages (Mɸ) concurrently stimulated with lipopolysaccharide as a pro-inflammatory stimulus, resulted in a dose dependent increase in pro-inflammatory IL6 but negligible effect on TNFα. To further investigate these functionalities, a bulk cell RNA sequence comparison with adult human bone marrow derived MSC and hESC substantiated a distinctive genetic signature more proximate to the former.

CONCLUSION

Cultivation of human pluripotent stem cells on a planar substrate of HA in serum-free culture media systems is sufficient to yield a distinctive developmental mesenchymal stromal cell lineage with potential to modify the function of haematopoietic lineages in therapeutic applications.

Recent advances of nanoparticles on bone tissue engineering and bone cells

With the development of biotechnology, biomaterials have been rapidly developed and shown great potential in bone regeneration therapy and bone tissue engineering. Nanoparticles have attracted the attention of researches and have applied in various fields especially in the biomedical field as the special physicochemical properties. Nanoparticles were found to regulate bone remodeling depending on their size, shape, composition, and charge. Therefore, in-depth research was necessary to provide the basic support to select the most suitable nanoparticles for bone relate diseases treatment. This article reviews the current development of nanoparticles in bone tissue engineering, focusing on drug delivery, gene delivery, and cell labeling. In addition, the research progress on the interaction of nanoparticles with bone cells, focusing on osteoblasts, osteoclasts, and bone marrow mesenchymal stem cells, and the underlying mechanism were also reviewed. Finally, the current challenges and future research directions are discussed. Thus, detailed study of nanoparticles may reveal new therapeutic strategies to improve the effectiveness of bone regeneration therapy or other bone diseases.

Mechanism of Bazi Bushen capsule in delaying the senescence of mesenchymal stem cells based on network pharmacology and experimental validation

Ageing is becoming an increasingly serious problem; therefore, there is an urgent need to find safe and effective anti-ageing drugs.

Aims

To investigate the effects of Bazi Bushen capsule (BZBS) on the senescence of mesenchymal stem cells (MSCs) and explore its mechanism of action.

Methods

Network pharmacology was used to predict the targets of BZBS in delaying senescence in MSCs. For in vitro studies, MSCs were treated with D-gal, BZBS, and NMN, and cell viability, cell senescence, stemness-related genes, and cell cycle were studied using cell counting kit-8 (CCK-8) assay, SA-β-galactosidase (SA-β-gal) staining, Quantitative Real-Time PCR (qPCR) and flow cytometry (FCM), respectively. Alkaline phosphatase (ALP), alizarin red, and oil red staining were used to determine the osteogenic and lipid differentiation abilities of MSCs. Finally, the expression of senescence-related genes and cyclin-related factors was detected by qPCR and western blotting.

Results

Network pharmacological analysis suggested that BZBS delayed cell senescence by interfering in the cell cycle. Our in vitro studies suggested that BZBS could significantly increase cell viability (P < 0.01), decrease the quantity of β-galactosidase+ cells (P < 0.01), downregulate p16 and p21 (P < 0.05, P < 0.01), improve adipogenic and osteogenic differentiation, and upregulate Nanog, OCT4 and SOX2 genes (P < 0.05, P < 0.01) in senescent MSCs. Moreover, BZBS significantly reduced the proportion of senescent MSCs in the G0/G1 phase (P < 0.01) and enhanced the expression of CDK4, Cyclin D1, and E2F1 (P < 0.05, P < 0.01, respectively). Upon treatment with HY-50767A, a CDK4 inhibitor, the upregulation of E2F1 was no longer observed in the BZBS group.

Conclusions

BZBS can protect MSCs against D-gal-induced senescence, which may be associated with cell cycle regulation via the Cyclin D1/CDK4/E2F1 signalling pathway.

Modulating Th1/Th2 drift in asthma-related immune inflammation by enhancing bone mesenchymal stem cell homing through targeted inhibition of the Notch1/Jagged1 signaling pathway

Asthma, a disease intricately linked to immune inflammation, is significantly influenced by the immune regulatory effect of bone mesenchymal stem cells (BMSCs). This study aims to investigate changes in the homing of BMSCs in bronchial asthma, focusing on the Notch homolog (Notch)1/Jagged1 signaling pathway's role in regulating T helper 1(Th1)/T helper 2(Th2) drift. Additionally, we further explore the effects and mechanisms of homologous BMSCs implantation in asthma-related immune inflammation. Following intervention with BMSCs, a significant improvement in the pathology of rats with asthma was observed. Simultaneously, a reduction in the expression of inflammatory cells and inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin(IL)-4, and IL-13 was observed in bronchoalveolar lavage fluid (BALF). Furthermore, there was an increase in the expression of Th1 cytokine Interferon-γ（IFN-γ）and the transcription factor T-box expressed in T cell (T-bet), while the expression of Th2 cytokine IL-13 and transcription factor GATA binding protein (GATA)-3 decreased in lung tissue. This indicates that the Th1/Th2 drift leans towards Th1, which a crucial in ameliorating asthma inflammation. Importantly, inhibition of the Notch1 signaling pathway led to an increased expression of the Stromal cell-derived factor-1(SDF-1)/C-X-C motif chemokine receptor (CXCR)4 chemokine axis. Consequently, the homing ability of bone marrow mesenchymal stem cells to asthma-affected lung tissue was significantly enhanced. BMSCs demonstrated heightened efficacy in regulating the cytokine/chemokine network and Th1/Th2 balance, thereby restoring a stable state during the immune response process in asthma. In conclusion, inhibiting the Notch signaling pathway enhances the expression of the SDF-1 and CXCR4 chemokine axis, facilitating the migration of allogeneic BMSCs to injured lung tissues. This, in turn, promotes immune regulation and improves the Th1/Th2 imbalance, thereby enhancing the therapeutic effect on asthmatic airway inflammation.

The Role and Prospects of Mesenchymal Stem Cells in Skin Repair and Regeneration

Mesenchymal stem cells (MSCs) have been recognized as a cell therapy with the potential to promote skin healing. MSCs, with their multipotent differentiation ability, can generate various cells related to wound healing, such as dermal fibroblasts (DFs), endothelial cells, and keratinocytes. In addition, MSCs promote neovascularization, cellular regeneration, and tissue healing through mechanisms including paracrine and autocrine signaling. Due to these characteristics, MSCs have been extensively studied in the context of burn healing and chronic wound repair. Furthermore, during the investigation of MSCs, their unique roles in skin aging and scarless healing have also been discovered. In this review, we summarize the mechanisms by which MSCs promote wound healing and discuss the recent findings from preclinical and clinical studies. We also explore strategies to enhance the therapeutic effects of MSCs. Moreover, we discuss the emerging trend of combining MSCs with tissue engineering techniques, leveraging the advantages of MSCs and tissue engineering materials, such as biodegradable scaffolds and hydrogels, to enhance the skin repair capacity of MSCs. Additionally, we highlight the potential of using paracrine and autocrine characteristics of MSCs to explore cell-free therapies as a future direction in stem cell-based treatments, further demonstrating the clinical and regenerative aesthetic applications of MSCs in skin repair and regeneration.

Stem Leydig cells support macrophage immunological homeostasis through mitochondrial transfer in mice

As testicular mesenchymal stromal cells, stem Leydig cells (SLCs) show great promise in the treatment of male hypogonadism. The therapeutic functions of mesenchymal stromal cells are largely determined by their reciprocal regulation by immune responses. However, the immunoregulatory properties of SLCs remain unclear. Here, we observe that SLCs transplantation restore male fertility and testosterone production in an ischemia‒reperfusion injury mouse model. SLCs prevent inflammatory cascades through mitochondrial transfer to macrophages. Reactive oxygen species (ROS) released from activated macrophages inducing mitochondrial transfer from SLCs to macrophages in a transient receptor potential cation channel subfamily member 7 (TRPM7)-mediated manner. Notably, knockdown of TRPM7 in transplanted SLCs compromised therapeutic outcomes in both testicular ischemia‒reperfusion and testicular aging mouse models. These findings reveal a new mechanism of SLCs transplantation that may contribute to preserve testis function in male patients with hypogonadism related to immune disorders.

Impacts of priming on distinct immunosuppressive mechanisms of mesenchymal stromal cells under translationally relevant conditions

BACKGROUND

The multimodal properties of mesenchymal stromal cells (MSCs), particularly their ability to modulate immune responses is of high interest in translational research. Pro-inflammatory, hypoxic, and 3D culture priming are promising and often used strategies to improve the immunosuppressive potency of MSCs, but the underlying mechanisms are not well understood. Therefore, the aims of this study were (i) to compare the effects of pro-inflammatory, hypoxic, and 3D culture priming on the in vitro immunosuppressive potential of MSCs, (ii) to assess if immunosuppressive priming effects are temporally preserved under standard and translationally relevant culture conditions, and (iii) to investigate if the three priming strategies engage the same immunosuppressive mechanisms.

METHODS

Functional in vitro T cell suppressive potency measurements were conducted to assess the impact of pro-inflammatory, hypoxic, and 3D culture priming on the immunosuppressive potential of human bone marrow-derived MSCs. Primed MSCs were either cultured under standard cell culture conditions or translationally relevant culture conditions, and their transcriptomic adaptations were monitored over time. Next-generation sequencing was performed to assess if different priming strategies activate distinct immunosuppressive mechanisms.

RESULTS

(i) Pro-inflammatory, hypoxic, and 3D culture priming induced profound transcriptomic changes in MSCs resulting in a significantly enhanced T cell suppressive potential of pro-inflammatory and 3D culture primed MSCs. (ii) Priming effects rapidly faded under standard cell culture conditions but were partially preserved under translationally relevant conditions. Interestingly, continuous 3D culture priming of MSCs maintained the immunosuppressive potency of MSCs. (iii) Next-generation sequencing revealed that priming strategy-specific differentially expressed genes are involved in the T cell suppressive capacity of MSCs, indicating that different priming strategies engage distinct immunosuppressive mechanisms.

CONCLUSION

Priming can be a useful approach to improve the immunosuppressive potency of MSCs. However, future studies involving primed MSCs should carefully consider the significant impact of translationally relevant conditions on the preservation of priming effects. Continuous 3D culture could act as a functionalized formulation, supporting the administration of MSC spheroids for a sustainably improved immunosuppressive potency.

Epigenetic mechanism of miR-26b-5p-enriched MSCs-EVs attenuates spinal cord injury

Mesenchymal stem cells (MSCs) and extracellular vesicles (EVs) are promising therapies for the treatment of spinal cord injury (SCI). This study sought to explore the epigenetic mechanism of miR-26b-5p-enriched MSCs-EVs in SCI. MSCs and MSCs-EVs were isolated and characterized. The SCI rat model was established, followed by Basso-Beattie-Bresnahan scoring and H&E staining. In vitro cell models were established in PC12 cells with lipopolysaccharide (LPS) treatment, followed by cell viability evaluation using CCK-8 assay. The levels of miR-26b-5p, lysine demethylase 6A (KDM6A), NADPH oxidase 4 (NOX4), reactive oxygen species (ROS), and inflammatory factors (TNF-α/IL-1β/IL-6) in tissues and cells were detected. The levels of cy3-lablled miR-26b-5p in tissues and cells were observed by confocal microscopy. The binding of miR-26b-5p to KDM6A 3'UTR and the enrichments of KDM6A and H3K27me3 at the NOX4 promoter were analyzed. MSCs-EVs attenuated motor dysfunction, inflammation, and oxidative stress in SCI rats. MSCs-EVs delivered miR-26b-5p into PC12 cells to reduce LPS-induced inflammation and ROS production and enhance cell viability. miR-26b-5p inhibited KDM6A, and KDM6A reduced H3K27me3 at the NOX4 promoter to promote NOX4. Overexpression of KDM6A or NOX4 reversed the alleviative role of MSCs-EVs in SCI or LPS-induced cell injury. Overall, MSCs-EVs delivered miR-26b-5p into cells to target the KDM6A/NOX4 axis and facilitate the recovery from SCI.

Biology and Therapeutic Properties of Mesenchymal Stem Cells in Leukemia

This comprehensive review delves into the multifaceted roles of mesenchymal stem cells (MSCs) in leukemia, focusing on their interactions within the bone marrow microenvironment and their impact on leukemia pathogenesis, progression, and treatment resistance. MSCs, characterized by their ability to differentiate into various cell types and modulate the immune system, are integral to the BM niche, influencing hematopoietic stem cell maintenance and functionality. This review extensively explores the intricate relationship between MSCs and leukemic cells in acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and chronic lymphocytic leukemia. This review also addresses the potential clinical applications of MSCs in leukemia treatment. MSCs' role in hematopoietic stem cell transplantation, their antitumor effects, and strategies to disrupt chemo-resistance are discussed. Despite their therapeutic potential, the dual nature of MSCs in promoting and inhibiting tumor growth poses significant challenges. Further research is needed to understand MSCs' biological mechanisms in hematologic malignancies and develop targeted therapeutic strategies. This in-depth exploration of MSCs in leukemia provides crucial insights for advancing treatment modalities and improving patient outcomes in hematologic malignancies.

Mesenchymal Stem Cell (MSC)-Based Drug Delivery into the Brain across the Blood-Brain Barrier

At present, stem cell-based therapies using induced pluripotent stem cells (iPSCs) or mesenchymal stem cells (MSCs) are being used to explore the potential for regenerative medicine in the treatment of various diseases, owing to their ability for multilineage differentiation. Interestingly, MSCs are employed not only in regenerative medicine, but also as carriers for drug delivery, homing to target sites in injured or damaged tissues including the brain by crossing the blood-brain barrier (BBB). In drug research and development, membrane impermeability is a serious problem. The development of central nervous system drugs for the treatment of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, remains difficult due to impermeability in capillary endothelial cells at the BBB, in addition to their complicated pathogenesis and pathology. Thus, intravenously or intraarterially administered MSC-mediated drug delivery in a non-invasive way is a solution to this transendothelial problem at the BBB. Substances delivered by MSCs are divided into artificially included materials in advance, such as low molecular weight compounds including doxorubicin, and expected protein expression products of genetic modification, such as interleukins. After internalizing into the brain through the fenestration between the capillary endothelial cells, MSCs release their cargos to the injured brain cells. In this review, I introduce the potential and advantages of drug delivery into the brain across the BBB using MSCs as a carrier that moves into the brain as if they acted of their own will.

Regulation Mechanisms and Maintenance Strategies of Stemness in Mesenchymal Stem Cells

Stemness pertains to the intrinsic ability of mesenchymal stem cells (MSCs) to undergo self-renewal and differentiate into multiple lineages, while simultaneously impeding their differentiation and preserving crucial differentiating genes in a state of quiescence and equilibrium. Owing to their favorable attributes, including uncomplicated isolation protocols, ethical compliance, and ease of procurement, MSCs have become a focal point of inquiry in the domains of regenerative medicine and tissue engineering. As age increases or ex vivo cultivation is prolonged, the functionality of MSCs decreases and their stemness gradually diminishes, thereby limiting their potential therapeutic applications. Despite the existence of several uncertainties surrounding the comprehension of MSC stemness, considerable advancements have been achieved in the clarification of the potential mechanisms that lead to stemness loss, as well as the associated strategies for stemness maintenance. This comprehensive review provides a systematic overview of the factors influencing the preservation of MSC stemness, the molecular mechanisms governing it, the strategies for its maintenance, and the therapeutic potential associated with stemness. Finally, we underscore the obstacles and prospective avenues in present investigations, providing innovative perspectives and opportunities for the preservation and therapeutic utilization of MSC stemness.

The global state of research in stem cells therapy for spinal cord injury (2003-2022): a visualized analysis

Objective

Our study aimed to visualize the global status and frontiers in stem cell therapy for spinal cord injury by using bibliometric methodology.

Methods

Publication citation information related to stem cell therapy for spinal cord injury (SCI) studies between 2003 and 2022 was retrieved from the Web of Science Core Collection database. For the visualized study, VOS viewer software and Graph Pad Prism 9.5 were used to perform bibliometric analysis of included data and publication number statistics in stem cell therapy for the SCI domain.

Results

A total of 6,686 publications were retrieved. The USA and China made the highest contributions to global research with the highest number of citations and link strength. The journal Experimental Neurology ranks as the top journal, combining the publication amount and bibliometrics results. The University of Toronto, based in Canada, was the first-ranking institution. The directions of the current study could be divided into five clusters. The research of Transplantation and Regenerative Medicine and Neurosciences Mechanism Research may be the emerging frontiers in this domain.

Conclusion

In summary, stem cell therapy for spinal cord injuries is poised for more valuable advances.

Special Issue "Mesenchymal Stromal Cells' Involvement in Human Diseases and Their Treatment"

Mesenchymal stromal cells (MSCs) are multipotent, non-hematopoietic cells that have the ability to differentiate into several mature cell types, including adipocytes, chondrocytes, osteoblasts, and myoblasts [...].

Future of low back pain: unravelling IVD components and MSCs' potential

Low back pain (LBP) mainly emerges from intervertebral disc (IVD) degeneration. However, the failing mechanism of IVD ́s components, like the annulus fibrosus (AF) and nucleus pulposus (NP), leading to IVD degeneration/herniation is still poorly understood. Moreover, the specific role of cellular populations and molecular pathways involved in the inflammatory process associated with IVD herniation remains to be highlighted. The limited knowledge of inflammation associated with the initial steps of herniation and the lack of suitable models to mimic human IVD ́s complexity are some of the reasons for that. It has become essential to enhance the knowledge of cellular and molecular key players for AF and NP cells during inflammatory-driven degeneration. Due to unique properties of immunomodulation and pluripotency, mesenchymal stem cells (MSCs) have attained diverse recognition in this field of bone and cartilage regeneration. MSCs therapy has been particularly valuable in facilitating repair of damaged tissues and may benefit in mitigating inflammation' degenerative events. Therefore, this review article conducts comprehensive research to further understand the intertwine between the mechanisms of action of IVD components and therapeutic potential of MSCs, exploring their characteristics, how to optimize their use and establish them safely in distinct settings for LPB treatment.

Mesenchymal stem cell-derived exosomes as delivery vehicles for non-coding RNAs in lung diseases

The burden of lung diseases is gradually increasing with an increase in the average human life expectancy. Therefore, it is necessary to identify effective methods to treat lung diseases and reduce their social burden. Currently, an increasing number of studies focus on the role of mesenchymal stem cell-derived exosomes (MSC-Exos) as a cell-free therapy in lung diseases. They show great potential for application to lung diseases as a more stable and safer option than traditional cell therapies. MSC-Exos are rich in various substances, including proteins, nucleic acids, and DNA. Delivery of Non-coding RNAs (ncRNAs) enables MSC-Exos to communicate with target cells. MSC-Exos significantly inhibit inflammatory factors, reduce oxidative stress, promote normal lung cell proliferation, and reduce apoptosis by delivering ncRNAs. Moreover, MSC-Exos carrying specific ncRNAs affect the proliferation, invasion, and migration of lung cancer cells, thereby playing a role in managing lung cancer. The detailed mechanisms of MSC-Exos in the clinical treatment of lung disease were explored by developing standardized culture, isolation, purification, and administration strategies. In summary, MSC-Exo-based delivery methods have important application prospects for treating lung diseases.

Regulatory Network of Methyltransferase-Like 3 in Stem Cells: Mechanisms and Medical Implications

Stem cells have the potential to replace defective cells in several human diseases by depending on their self-renewal and differentiation capacities that are controlled by genes. Currently, exploring the regulation mechanism for stem cell capacities from the perspective of methyltransferase-like 3 (METTL3)-mediated N6-methyladenosine modification has obtained great advance, which functions by regulating target genes post-transcriptionally. However, reviews that interpret the regulatory network of METTL3 in stem cells are still lacking. In this review, we systematically analyze the available publications that report the role and mechanisms of METTL3 in stem cells, including embryonic stem cells, pluripotent stem cells, mesenchymal stem cells, and cancer stem cells. The analysis of such publications suggests that METTL3 controls stem cell fates and is indispensable for maintaining its normal capacities. However, its dysfunction induces various pathologies, particularly cancers. To sum up, this review suggests METTL3 as a key regulator for stem cell capacities, with further exploration potential in translational and clinical fields. In conclusion, this review promotes the understanding of how METTL3 functions in stem cells, which provides a valuable reference for further fundamental studies and clinical applications.

Mesenchymal Stem Cells: A Promising Treatment for Thymic Involution

The thymus is the main immune organ in the body. However, the thymus gradually degenerates in early life, leading to a reduction in T-cell production and a decrease in immune function. Mesenchymal stem cells (MSCs) are a promising alternative for the treatment of thymus senescence due to their homing ability to the site of inflammation and their paracrine, anti-inflammatory, and antioxidant properties. However, the heterogeneity, difficulty of survival in vivo, short residence time, and low homing efficiency of the injected MSCs affect the clinical therapeutic effect. This article reviews strategies to improve the efficacy of mesenchymal stem cell therapy, including the selection of appropriate cell doses, transplantation frequency, and interval cycles. The survival rate of MSCs can be improved to some extent by improving the infusion mode of MSCs, such as simulating the in vivo environment, applying the biological technology of hydrogels and microgels, and iron oxide labeling technology, which can improve the curative effect and homing of MSCs, promote the regeneration of thymic epithelial cells, and restore the function of the thymus.