The secretion profile of mesenchymal stem cells and potential applications in treating human diseases

Single-cell Raman spectroscopy as a novel platform for unveiling the heterogeneity of mesenchymal stem cells

Despite the significant potential of mesenchymal stem cells (MSC) therapy in clinical settings, challenges persist regarding the efficient detection of consistency and uniformity of MSC populations. Raman spectroscopy is a fast, convenient, and nondestructive technique to acquire molecular properties of biomolecules across laboratory and mass-production settings. Here we utilized Raman spectroscopy to evaluate the heterogeneity of primary MSC from varying donors, passages, and distinct culture conditions, and compared its effectiveness with conventional techniques such as flow cytometry. Although these MSC exhibited insignificant differences in morphology and surface markers in flow cytometry analysis, they could be distinctly clustered into different populations by Raman spectroscopy and the subsequent machine learning using linear discriminant analysis. Principal component analysis demonstrated limited efficiency in clustering Raman data from diverse sources, which could be enhanced through combination with support vector machine or deterministic finite automation. These findings highlight the sensitivity of Raman spectroscopy in detecting subtle differences. Moreover, the analysis of characteristic Raman peaks attributed to cellular biomolecules in MSC from passages 2 (P2) to P10 revealed a gradual decrease in the levels of nucleic acids, lipids, and proteins with increasing passages, and a significant increase in carotenoids from P8. These results suggest the potential use of Raman spectroscopy to assess cellular biochemical characteristics such as aging, with carotenoids emerging as a potential marker of cell aging. In conclusion, Raman spectroscopy demonstrates the ability to rapidly and non-invasively detect cellular heterogeneity and biochemical status, offering significant potential for quality control in stem cell therapy.

Effects of Wharton's jelly mesenchymal stromal/stem cells-derived conditioned medium and platelet-rich plasma on in vitro induced equine endometrial inflammation

Over the years, regenerative therapies have emerged as promising alternatives for persistent breeding-induced endometritis. In vitro studies testing the effects of these therapies on equine endometrial cells are still scarce. This study aimed to evaluate in vitro the effect of Wharton's jelly (WJ) mesenchymal stromal/stem cell (MSCs)-derived conditioned medium (WJ-CM) and platelet-rich plasma (PRP) on equine endometrial cells, with or without lipopolysaccharide (LPS)-induced inflammation. The WJ-CM was obtained after 24 h of starvation in Ringer's lactate of WJ-MSCs and PRP was prepared using the double centrifugation. Endometrial epithelial cells obtained from 3 diestrus mare uteri at slaughterhouse were treated for 24 h according to six experimental groups: DMEM standard complete medium (CTRL); 10 ng/mL LPS (LPS); 10 % WJ-CM (CM); 5 % PRP (PRP); 10 ng/mL LPS and 10 % WJ-CM (LPS + CM); 10 ng/mL LPS and 5 % PRP (LPS + PRP). After 6, 12, and 24 h, endometrial cells were evaluated for viability (apoptosis and necrosis), mitochondrial activity and reactive oxygen species (ROS) generation. PGE-2 and IL-10 concentrations in spent medium were measured. The WJ-CM alone did not affect endometrial cell viability and prevented the detrimental effect of LPS on endometrial cells; it suppressed the production of PGE-2. PRP had a deleterious effect on endometrial cell viability, induced the secretion of PGE-2, as well as increased mitochondrial activity and ROS production. Endometrial benefits of the WJ-CM treatment are evident even after an LPS challenge, while unexpectedly PRP showed a deleterious effect.

Exosomal miRNA combined with anti-inflammatory hyaluronic acid-based 3D bioprinted hepatic patch promotes metabolic reprogramming in NAFLD-mediated fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a complex metabolic disorder, where the underlying molecular mechanisms are mostly not well-understood and therefore, warrants the need for therapeutic interventions targeting several metabolic pathways as a unified response. Of late, promising outcomes have been observed with mesenchymal stem cell-derived exosomes. However, reduced bioavailability due to systemic delivery and the need for repeated fresh isolation hinders their feasibility for clinical applications. In this regard, an 'off-the-shelf' 3D bioprinted hyaluronic acid-based hepatic patch to deliver encapsulated exosomes alone/or with hepatocytes (as dual-therapy) is developed as a holistic approach for ameliorating the disease condition and promoting tissue regeneration. The bioprinted hepatic patch demonstrated sustained and localized release of exosomes (∼82 % in 21 days), and healthy liver tissue-like mechanical properties while being biocompatible and biodegradable. Assessment in NAFLD rat models displayed alleviation of the altered biochemical parameters such as fat deposition, deranged liver functions, disrupted lipid, glucose, and insulin metabolism along with a reduction in localized inflammation, and associated liver fibrosis. The study suggests that a synergistic effect between the miRNA population of released exosomes, cell therapy, and the bioprinted matrix materials is crucial in targeting multiple complex metabolic pathways associated with the severity of the disease.

Nanoemulgel Development of Stem Cells from Human Exfoliated Deciduous Teeth-Derived Conditioned Medium as a Novel Nanocarrier Growth Factors

OBJECTIVE

 We aimed to develop a nanoemulgel of stem cells from human exfoliated deciduous teeth-derived conditioned medium (SHED-CM) for oral wound biotherapy candidate.

MATERIALS AND METHODS

 Deciduous tooth pulp was collected from two patients aged 6 years. The mesenchymal stem cell marker expression was analyzed by immunocytochemistry of CD45, CD90, and CD105. Alizarin red staining was performed to differentiate SHEDs from osteoblasts. The quantitative and quantification of transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF) secreted into conditioned media were measured using sodium dodecyl sulfate polyacrylamide gel electrophoresis and enzyme-linked immunosorbent assay. The characteristics of the nanoemulgel of SHED-CM (NESCM) were analyzed in terms of organoleptic properties, pH, and homogeneity. The cytotoxicity of NESCM 1.5% was analyzed in human gingival fibroblast (hGF) cell and osteoblast cell line (MC3T3) by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay.

STATISTICAL ANALYSIS

 The results were presented as mean ± standard deviation (X ± SD), and the differences between groups were analyzed using the post hoc Tukey's test at a significance level of p-value < 0.05.

RESULTS

 SHEDs were successfully isolated, which were characterized for positive marker expressions of CD90 and CD105 and negative expression of CD45 as well as their osteogenic commitment. In SHED-CM, TGF-β and VEGF were detected on day 1 of conditioning and afterward. Notably, the growth factor enriched as the duration of conditioning increased. The generated nanoemulgel with SHED-CM was stable and homogeneous, and had limited cytotoxic effects on hGF and MC3T3 cell culture.

CONCLUSION

 SHED-CM containing the growth factors can potentially be used as oral wound biotherapy in the form of nanoemulgel.

Secretome Derived From Mesenchymal Stem Cells Cultured as Monolayer Show Enhanced Bone Regeneration Compared to Secretome From 3D Spheroid - Clues From the Proteome

Repair and reconstruction of critical-sized bone defects present a significant challenge due to poor clinical outcomes of conventional bone repair strategies, such as autologous and allogenic bone grafts. The present study underscores the potential of human dental pulp stem cell-derived trophic factors to promote bone repair and regeneration, thus evading the risks associated with cell-based therapy. This study utilizes pre-osteoblast cells to evaluate the osteogenic potential of 2 Dimensional (2D) and 3 Dimensional (3D) secretome from monolayer and spheroid cultures of dental pulp stem cells (DPSCs), respectively. In-vitro results on pre-osteoblast cells (MC3T3-EI) treated with 2D and 3D secretome reveal lower mineralization and mRNA expression of osteogenic specific genes in 3D secretome in comparison to 2D secretome. Furthermore, 2D secretome shows better bone regeneration ability in rat models of calvarial bone defect compared to the 3D secretome. The proteomic profiles of 2D and 3D secretomes are also in concordance with these results and reveal key molecules governing bone regeneration potential. This data highlights the influence of culture conditions on the secretory pattern of mesenchymal stem cells and provides valuable insights for the development of a more effective secretome-based cell-free alternative for novel bone repair and regeneration.

Targeted Dual Microdroplets for Modulating Osteoclast Differentiation and Function: A Novel Therapeutic Approach to Combat Osteoporosis

Osteoporosis, a condition marked by reduced bone mass and structural deterioration, continues to be a major public health concern, especially as global populations age. Excessive osteoclast formation is a hallmark of osteoporosis. The transcription factor nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) is indispensable for the early differentiation of osteoclasts, orchestrating the expression of essential genes, while at the later stages, cathepsin K (CTSK) is essential for bone resorption activities of mature osteoclasts. Here, we fabricated ultrasound-responsive microdroplets (MDs) by modulating both the early stages of osteoclast differentiation and the functions of mature osteoclasts via targeting the NFATc1 and CTSK. The internalization of these dual MDs was evaluated in human bone marrow-derived mesenchymal stromal cells (hBMSCs) and murine RAW 264.7 macrophages, alongside the biocompatibility assay. Their effects on osteogenesis and osteoclastogenesis were further investigated in vitro, followed by in vivo analysis in osteoporotic rat models. The dual MDs exhibited a well-defined core-shell structure and demonstrated efficient cellular uptake with minimal cytotoxicity. Furthermore, dual MDs showed a minimal effect on the osteogenic differentiation of the hBMSCs. In in vitro osteoclastogenesis assays, dual MDs effectively suppressed both osteoclast differentiation and formation through a synergistic inhibitory effect. In vivo studies demonstrated that osteoporotic rats receiving dual MDs showed significant protection against bone loss induced by ovariectomy. These results highlight the potential of dual MDs as a sophisticated, targeted therapeutic approach to osteoporosis treatment.

Advances in Cell-based therapies for peripheral arterial disease

PURPOSE

To examine recent advances in cell-based therapies for peripheral arterial disease (PAD), focusing on mechanisms of action, clinical applications, and regulatory considerations. The review aimed to evaluate the therapeutic potential of various cell types and assess their efficacy in addressing the unmet needs of PAD patients,particularly those with critical limb ischemia (CLI).

METHODS

The review analysed current literature on cell-based therapies for PAD, including preclinical studies using animal models, clinical trials from phase I to III, and regulatory frameworks. Multiple cell types were evaluated, including mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs), bone marrow mononuclear cells (BMMNCs),and adipose-derived stem cells (ADSCs).

RESULTS

Preclinical studies demonstrated significant improvements in limb perfusion and neovascularization across various cell types. Clinical trials, particularly those utilizing MSCs and BM-MNCs, showed encouraging outcomes in wound healing and reduced amputation rates. The therapeutic effects were mediated through multiple mechanisms, including direct vessel formation, paracrine signalling, immunomodulation, and tissue repair. The FDA's implementation of a tiered, risk-based system for human cells, tissues, and cellular and tissue-based products (HCT/Ps) has provided a regulatory framework balancing innovation with safety.

CONCLUSION

Cell-based therapies show promising potential for PAD treatment, particularly for patients with limited conventional treatment options. While clinical trials demonstrate encouraging results, challenges remain in standardizing cell characterization methods and establishing appropriate potency assays. Future research should focus on optimizing cell delivery methods, identifying the most effective cell types, and conducting larger clinical trials to establish definitive efficacy.

Advancements in Degenerative Disc Disease Treatment: A Regenerative Medicine Approach

Regenerative medicine represents a transformative approach to treating nucleus pulposus degeneration and offers hope for patients suffering from chronic low back pain due to disc degeneration. By focusing on restoring the natural structure and function of the nucleus pulposus rather than merely alleviating symptoms, these innovative therapies hold the potential to significantly improve patient outcomes. As research continues to advance in this field, we may soon witness a paradigm shift in how we approach spinal health and degenerative disc disease. The main purpose of this review is to provide an overview of the various regenerative approaches that target the restoration of the nucleus pulposus, a primary site for initiation of intervertebral disc degeneration.

Development of regenerative therapies targeting fibrotic endometrium in intrauterine adhesion or thin endometrium to restore uterine function

Intrauterine adhesions (IUA) and thin endometrium (TE) represent significant challenges in human reproduction. The condition arises frequently from damage to the endometrial basal layer, leading to fibrous tissue replacing the functional endometrium and impairing the uterus's ability to accept embryo implantation. Conventional treatments, mainly including hysteroscopic adhesiolysis and estrogen therapies, have shown limited success, particularly in severe cases. Regenerative medicine, with its focus on stem cell-based therapies and biomaterials, offers a promising avenue for restoring endometrial function and structure. This review synthesizes the current landscape of endometrial regeneration, focusing on the therapeutic potential of stem cells, the supportive role of biomaterials, and the importance of understanding molecular mechanisms to develop effective strategies for reconstruction of endometrial functional and fertility restoration.

Umbilical cord stem cells therapy against bacterial pneumonia based on zebrafish pneumonia model

Background

The increasing incidence and mortality rates of respiratory system diseases globally pose a significant public health challenge. Bacterial pneumonia is one of the leading risk factors for acute lung injury. Conventional antibiotics face inherent limitations, particularly the increase in bacterial resistance and inability to suppress inflammatory states, underscoring the urgent need for novel approaches to combat bacterial pneumonia.

Methods

This study evaluated the therapeutic effects of umbilical cord mesenchymal stem cells (UC-MSCs) on bacterial pneumonia in a zebrafish model, focusing on their impact on macrophage and neutrophil counts and their inhibitory effects on in vivo inflammatory responses. The anti-inflammatory mechanisms of UC-MSCs, including their effects on the secretion of inflammatory factors IL-1β, IL-6, and TNF-α, as well as their regulation of NLRP3, TLR4, and NF-kB mRNA expression and NLRP3, p65, and TLR4 protein levels, were further investigated.

Results

Our study found that UC-MSCs can effectively inhibit the development of bacterial pneumonia, primarily by reducing the number of macrophages and neutrophils and inhibiting the secretion of inflammatory factors IL-1β, IL-6, and TNF-α, thereby suppressing in vivo inflammatory reactions. Additionally, UC-MSCs significantly downregulated the expression of NLRP3, TLR4, and NF-kB mRNA, as well as the levels of NLRP3,TLR4, and p65 proteins.

Conclusion

UC-MSCs demonstrate promising potential in the treatment of bacterial pneumonia. This study provides important reference for the therapeutic effects and mechanisms of stem cell treatment of bacterial pneumonia, offering new avenues for clinical applications.

Therapeutic application of extracellular vesicles in human diseases

Extracellular vesicles (EVs) are membrane vesicles released or secreted from almost all cell types. EVs are derived from multivesicular bodies or from the plasma membrane and contain a subset of proteins, lipids, and nucleic acids (e.g., DNA, RNA, and microRNA [miRNA]) derived from the parent cell. EVs play important roles in intercellular communication by efficiently transferring the content between cells both locally and systemically. Given their natural ability to transfer cargo to cells, sometimes in a targeted manner, and their apparent lack of immunogenicity, EVs are being engineered for delivery of therapeutic RNAs, DNAs, miRNAs, viral particles, drugs, and even proteins. In addition, many of the therapeutic effects of stem cell treatments are mediated by stem cell-derived EVs, which are safer and potentially more effective than the parental stem cells. Here we provide an overview of the use of EVs for delivery of different therapeutic nucleic acids, viruses, and drugs, as well as the use of therapeutic stem cell-derived EVs.

Extracellular vesicles derived from mesenchymal stem cells alleviate depressive-like behavior in a rat model of chronic stress

Depression is a prevalent chronic psychiatric disorder with a growing impact on global health. Current treatments often fail to achieve full remission, highlighting the need for alternative therapeutic strategies. Mesenchymal stem cells (MSCs) have attracted significant interest for their therapeutic potential in neuropsychiatric disorders, primarily due to their capacity to target neuroinflammation. This study aimed to investigate if extracellular vesicles derived from human umbilical MSCs (hucMSCs) promote behavioral beneficial actions in a rat model of chronic unpredictable mild stress (CUMS). We show that a single dose of hucMSCs or their derived EVs (hucMSC-EVs) via the tail vein alleviated depressive-like behavior in rats, reduced markers of neuroinflammation, reduced pro-inflammatory cytokines (IL-1β and TNF-α), and increased the number and dendritic complexity of DCX-positive cells in the dentate gyrus. Proteomic analysis of EVs revealed the presence of proteins involved in modulation of inflammatory processes and cell activation. Our study demonstrates EVs derived from hucMSCs can effectively mitigate depressive symptoms by modulating neuroinflammatory pathways and enhancing neurogenesis. These findings support further exploration of MSC-derived EVs as a novel therapeutic option for neuropsychiatric disorders.

Emerging Treatments for Persistent Corneal Epithelial Defects

Persistent corneal epithelial defects (PCEDs) are a challenging ocular condition characterized by the failure of complete corneal epithelial healing after an insult or injury, even after 14 days of standard care. There is a lack of therapeutics that target this condition and encourage re-epithelialization of the corneal surface in a timely and efficient manner. This review aims to provide an overview of current standards of management for PCEDs, highlighting novel, emerging treatments in this field. While many of the current non-surgical treatments aim to provide lubrication and mechanical support, novel non-surgical approaches are undergoing development to harness the proliferative and healing properties of human mesenchymal stem cells, platelets, lufepirsen, hyaluronic acid, thymosin ß4, p-derived peptide, and insulin-like growth factor for the treatment of PCEDs. Novel surgical treatments focus on corneal neurotization and limbal cell reconstruction using novel scaffold materials and cell-sources. This review provides insights into future PCED treatments that build upon current management guidelines.

UC-MSCs based on biomimetic microniche exert excellent regulatory effects on acute brain inflammation through advantageous properties

Neuroinflammation triggered by activated microglia leads to neuronal damage and, to a certain extent, neurodegeneration. Human umbilical cord mesenchymal stem cells (UC-MSCs) have good immunomodulatory and neuroprotective effects as well as therapeutic potential for neuroinflammation-related diseases. However, the complex microenvironment created by neuroinflammation poses a challenge to transplanted UC-MSCs. The emerging biomimetic microniche (BN)-based culture technology provides new opportunities to optimize the preparation of UC-MSCs; but the fundamental changes in the characteristics of UC-MSCs based on BN remain unclear, and more reliable preclinical data are needed to support their ability to regulate inflammation. Here, we systematically studied the cellular properties and inflammation regulatory capacity of UC-MSCs in conventional static planar culture (SP-UCMSCs) and suspension culture based on BN (BN-UCMSCs). In vitro, compared with SP-UCMSCs, BN-UCMSCs not only maintained the fundamental characteristics of MSCs, but also significantly enhanced cell proliferation, adhesion, and migration capabilities, etc; notably, the paracrine function and anti-inflammatory capacity of BN-UCMSCs were also enhanced. We further established a murine model of acute brain inflammation and demonstrated that the expression level of pro-inflammatory cytokines in hippocampal and cortical tissues of the BN-UCMSCs group was significantly decreased compared with that in the SP-UCMSCs group. Subsequent transcriptomic analysis of hippocampal and cortical tissues revealed that BN-UCMSCs had the advantage of significantly reducing the expression of pro-inflammatory cytokines through the TLR4-Myd88-NF-κB axis, which was further validated at the gene and protein levels. Taken together, these data strongly indicated that BN-UCMSCs exerts excellent regulatory effects on acute brain inflammation through advantageous properties.

Innovative approaches to boost mesenchymal stem cells efficacy in myocardial infarction therapy

Stem cell-based therapy has emerged as a promising approach for heart repair, potentially regenerating damaged heart tissue and improving outcomes for patients with heart disease. However, the efficacy of stem cell-based therapies remains limited by several challenges, including poor cell survival, low retention rates, poor integration, and limited functional outcomes. This article reviews current enhancement strategies to optimize mesenchymal stem cell therapy for cardiac repair. Key approaches include optimizing cell delivery methods, enhancing cell engraftment, promoting cell functions through genetic and molecular modifications, enhancing the paracrine effects of stem cells, and leveraging biomaterials and tissue engineering techniques. By focusing on these enhancement techniques, the paper highlights innovative approaches that can potentially transform stem cell therapy into a more viable and effective treatment option for cardiac repair. The ongoing research and technological advancements continue to push the boundaries, hoping to make stem cell therapy a mainstream treatment for heart disease.

Crosslinking stabilization strategy: A novel approach to cartilage-like repair of annulus fibrosus (AF) defects

Lumbar disc degeneration due to annulus fibrosus (AF) defects poses a significant challenge in clinical treatment Current treatments exhibit limited repair efficacy and a high recurrence rate. To address this, we devised a novel approach of crosslinking stabilization strategy. We integrated fibrinogen, thrombin, genipin, and human bone marrow-derived mesenchymal stem cells (hBMSCs) hydrogel (FTGB) with acellular scaffold and fascia (FTGB@S@F) to remediate AF defects. FTIR analysis confirmed stable chemical crosslinking within the FTGB hydrogel. FTGB hydrogel demonstrated superior biocompatibility compared to the FB hydrogel, with significantly higher cell viability (97.60 ± 2.02 % vs 81.43 ± 4.50 %, P < 0.01) and enhanced proliferation and migration, as shown in DAPI, Edu and phalloidin staining. Atomic force microscopy (AFM) revealed that FTGB@S has a dense reticular structure, enhancing material performance with higher elastic modulus than FB@S. MTS testing showed that FTGB@S@F outperformed other groups in resisting cyclic axial load (25.53 ± 1.17 MPa) and maintaining disc height (0.57 ± 0.12 mm), with stable axial compression resistance and minimal deformation. It also exhibited the lowest rupture ROM (1.45 ± 0.17 mm) and a rupture modulus close to the Intact control, demonstrating its potential to restore AF mechanical function. MRI imaging revealed that the FTGB@S@F group preserved an intact AF structure with high signal intensity, a significantly larger NP area (223.64 ± 73.32 mm2 vs 137.30 ± 75.31 mm2, P < 0.05), and higher disc height (102.5 ± 73.32 % vs 88.50 ± 12.86 %, P < 0.05). Histology confirmed superior AF repair and reduced NP degeneration in the FTGB@S@F group compared to the Un-repair and FB@S@F groups. Transcriptomic analysis identified upregulation of PIGR and downregulation of COL4A3, linked to the PI3K-Akt pathway. Immunohistochemical and qPCR analyses showed enhanced expression of COL1, Aggrecan, and RhoA, indicating effective regeneration.

Mesenchymal stromal cells in bone marrow niche of patients with multiple myeloma: a double-edged sword

Multiple myeloma (MM) is a hematological malignancy defined by the abnormal proliferation and accumulation of plasma cells (PC) within the bone marrow (BM). While multiple myeloma impacts the bone, it is not classified as a primary bone cancer. The bone marrow microenvironment significantly influences the progression of myeloma and its treatment response. Mesenchymal stromal cells (MSCs) in this environment engage with myeloma cells and other bone marrow components via direct contact and the secretion of soluble factors. This review examines the established roles of MSCs in multiple facets of MM pathology, encompassing their pro-inflammatory functions, contributions to tumor epigenetics, effects on immune checkpoint inhibitors (ICIs), influence on reprogramming, chemotherapy resistance, and senescence. This review investigates the role of MSCs in the development and progression of MM.

Clinical translation of mesenchymal stem cells in ischemic heart failure: Challenges and future perspectives

Myocardial infarction (MI) with resulting congestive heart failure is one of the leading causes of death worldwide. Current therapies for treating MI, such as devices, traditional medicine, and surgeries, come with many limitations as patients in their final stages of heart failure have little chances of experiencing any reversible changes. In recent decades, Mesenchymal stem cell (MSC) based therapy has become one of the most popular and rapidly developing fields in treating MI. Their supremacy for clinical applications is partially due to their unique properties and encouraging pre-clinical outcomes in various animal disease models. However, the majority of clinical trials registered for MSC therapy for diverse human diseases, including MI, have fallen short of expectations. This review intends to discuss the recent advances in the clinical application of using MSCs for cardiac repair and discuss challenges facing the clinical translation of MSCs for cardiac regeneration such as restoration of endothelial-cardiomyocyte crosstalk, immunomodulation and immune rejection, poor homing and migration, as well as low retention and survival. Furthermore, we will discuss recent strategies being investigated to help overcome some of these challenges.

Mesenchymal stem cells therapy for the treatment of non-union fractures: a systematic review and meta-analysis

BACKGROUND

This meta-analysis aimed to pool the existing evidence to determine the clinical efficacy and safety of mesenchymal stem cells (MSC) in patients with non-unions.

METHODS

A systematic search in PubMed and Scopus was performed until October 2024 to gather pertinent studies. The inclusion criteria included participants with non-unions, the intervention of MSC administration, a comparator of standard treatment (bone graft), and outcomes focused on healing rate, healing time, or side effects. The Jadad score Newcastle-Ottawa Scale (NOS) was used to assess the risk of bias in randomized and non-randomized studies, respectively. Moreover, GRADE criteria were used to assess the quality of evidence. Using a random effects model, odds ratios (OR) with 95% confidence intervals (CIs) were calculated for healing and complication rates, while standardized mean differences (SMD) with their 95% CIs were used to assess the impact of MSC therapy on bone union time.

RESULTS

Twenty-one studies, with 866 patients, were included. The bone healing rates were 44% at 3 months, 73% at 6 months, 90% at 9 months, and 86% at 12 months, eventually reaching 91% after 12 months of follow-up. MSC therapy, with or without scaffolds, was linked to higher odds of bone healing rate at 3 and 6 months, compared to bone grafts as the standard care (OR = 1.69). The time to union following the treatment was 6.30 months (95%CI: 86-96%), with patients treated with MSC/Scaffold experiencing a shorter time compared to MSC alone (5.85 vs. 6.36 months). MSC therapy significantly decreased bone union time (SMD:-0.54 months, 95% CI: -0.75 to -0.33). The complication rate was 1% (MSC/Scaffold: 0%, MSC alone: 2%), with MSC alone or MSC/Scaffold showing a lower risk than the standard care (OR = 0.41, 95% CI: 0.22-0.78).

CONCLUSION

MSC is a potential adjunct therapy for patients with non-union fractures.

CLINICAL TRIAL NUMBER

Not applicable.

Regulation and functional importance of human periodontal ligament mesenchymal stromal cells with various rates of CD146+ cells

Introduction

Mesenchymal stromal cells (MSCs) with high expression of CD146 have superior properties for tissue regeneration. However, high variability in the rate of CD146+ cells among donors is observed. In this study, the possible reasons behind this variability in human periodontal ligament MSCs (hPDL-MSCs) were explored.

Methods

hPDL-MSCs were isolated from 22 different donors, and rates of CD146+ cells were analyzed by flow cytometry. Furthermore, populations with various rates of CD146+ cells were isolated with magnetic separation. The dependency of cell proliferation, viability, cell cycle, and osteogenic differentiation on the rates of CD146+ cells was investigated. Besides, the effects of various factors, like cell density, confluence, and inflammatory environment on the CD146+ rate and expression were analyzed.

Results

The rate of CD146+ cells exhibited high variability between donors, with the percentage of CD146+ cells ranging from 3% to 67%. Higher percentage of CD146+ cells was associated with higher proliferation, presumably due to the higher percentage of cells in the S-phase, and higher osteogenic differentiation potential. Prolonged cell confluence and higher cell seeding density led to the decline in the rate of CD146+ cells. The surface rate of CD146 in hPDL-MSCs was stimulated by the treatment with interleukin-1β and tumor necrosis factor-α, and inhibited by the treatment with interferon-γ.

Conclusion

These results suggest that hPDL-MSCs with high rate of CD146+ cells are a promising subpopulation for enhancing the effectiveness of MSC-based regenerative therapies, however the rate of CD146 is affected by various factors, which must be considered for cell propagation and their potential application in vivo.

Hybrid Biomembrane-Functionalized Nanorobots Penetrate the Vitreous Body of the Eye for the Treatment of Retinal Vein Occlusion

Intravitreal injections of antivascular endothelial growth factor (VEGF) agents are the primary method for treating retinal vein occlusion (RVO). However, the complex structure of eye anatomy presents ocular barriers that impede drug delivery. Additionally, these drugs only manage the complications associated with RVO and fail to address the underlying cause of vessel occlusions. Here, we describe a method that utilizes functionalized magnetically driven nanorobots to overcome ocular barriers and treat RVO. These nanorobots are developed using a hybrid biomembrane that combines stem cell membranes with liposome-derived membranes, enveloping perfluorohexane, iron oxide nanoparticles, and l-arginine. After intravitreal injection, the nanorobots can move directionally through and penetrate the vitreous body to reach the retina, driven by an external magnetic field. Subsequently, the nanorobots actively target the inflammation sites at occluded vessels due to the presence of stem cell membranes. In a rat model of RVO, enhanced targeting and accumulation in ischemic retinal vessels were demonstrated following intravitreal injections. Furthermore, the application of ultrasound triggers the release of l-arginine at the site of occlusion, stimulating the production of nitric oxide, which promotes vasodilation and restores blood flow, thereby achieving excellent therapeutic efficacy for RVO. We believe these methods hold significant promise for overcoming challenges in ocular drug delivery and effectively treating RVO in clinical applications.

Advanced nano delivery system for stem cell therapy for Alzheimer's disease

Alzheimer's Disease (AD) represents one of the most significant neurodegenerative challenges of our time, with its increasing prevalence and the lack of curative treatments underscoring an urgent need for innovative therapeutic strategies. Stem cells (SCs) therapy emerges as a promising frontier, offering potential mechanisms for neuroregeneration, neuroprotection, and disease modification in AD. This article provides a comprehensive overview of the current landscape and future directions of stem cell therapy in AD treatment, addressing key aspects such as stem cell migration, differentiation, paracrine effects, and mitochondrial translocation. Despite the promising therapeutic mechanisms of SCs, translating these findings into clinical applications faces substantial hurdles, including production scalability, quality control, ethical concerns, immunogenicity, and regulatory challenges. Furthermore, we delve into emerging trends in stem cell modification and application, highlighting the roles of genetic engineering, biomaterials, and advanced delivery systems. Potential solutions to overcome translational barriers are discussed, emphasizing the importance of interdisciplinary collaboration, regulatory harmonization, and adaptive clinical trial designs. The article concludes with reflections on the future of stem cell therapy in AD, balancing optimism with a pragmatic recognition of the challenges ahead. As we navigate these complexities, the ultimate goal remains to translate stem cell research into safe, effective, and accessible treatments for AD, heralding a new era in the fight against this devastating disease.

The therapeutic potential of mesenchymal stromal cell secretome in treating spontaneous chronic corneal epithelial defects in dogs

Corneal ulcers in dogs pose a significant challenge in veterinary ophthalmology, often leading to prolonged visual impairment and discomfort. This study aimed to assess the efficacy of adipose tissue-derived mesenchymal stromal cell (ASCs) secretome as a treatment for complicated corneal ulcers in dogs. Ten dogs with spontaneous chronic corneal epithelial defects, were treated with topical application of ASC secretome eye drops. Our results showed that secretome therapy facilitated complete healing of all corneal ulcers within 4 weeks, with an average healing time of 1.2 weeks. Notably, secretome treatment was effective even in cases that had previously failed to respond to conventional therapies. Clinical signs such as blepharospasm, conjunctival hyperemia, and photophobia were alleviated promptly following secretome administration. Secretome therapy was well-tolerated, with no adverse reactions reported, further supporting its safety profile. The findings suggest that ASC secretome represents a promising cell-free and minimally invasive therapeutic approach for the treatment of complicated corneal ulcers in dogs.

3D Mechanical Response Stem Cell Complex Repairs Spinal Cord Injury by Promoting Neurogenesis and Regulating Tissue Homeostasis

Spinal cord injury (SCI) leads to acute tissue damage that disrupts the microenvironmental homeostasis of the spinal cord, inhibiting cell survival and function, and thereby undermining treatment efficacy. Traditional stem cell therapies have limited success in SCI, due to the difficulties in maintaining cell survival and inducing sustained differentiation into neural lineages. A new solution may arise from controlling the fate of stem cells by creating an appropriate mechanical microenvironment. In this study, mechanical response stem cell complex (MRSCC) is created as an innovative therapeutic strategy for SCI, utilizing 3D bioprinting technology and gelatin microcarriers (GM) loaded with mesenchymal stem cells (MSCs). GM creates an optimal microenvironment for MSCs growth and paracrine activity. Meanwhile, 3D bioprinting allows accurate control of spatial pore architecture and mechanical characteristics of the cell construct to encourage neuroregeneration. The mechanical microenvironment created by MRSCC is found to activate the Piezo1 channel and prevent excessive nuclear translocation of YAP, thereby increasing neural-related gene expression in MSCs. Transplanting MRSCC in rats with spinal cord injuries boosts sensory and motor recovery, reduces inflammation, and stimulates the regeneration of neurons and glial cells. The MRSCC offers a new tissue engineering solution that can promote spinal cord repair.

Mesenchymal Stem Cell Secretome: Potential Applications in Human Infertility Caused by Hormonal Imbalance, External Damage, or Immune Factors

Mesenchymal stem cells (MSCs) are a source of a wide range of soluble factors, including different proteins, growth factors, cytokines, chemokines, and DNA and RNA molecules, in addition to numerous secondary metabolites and byproducts of their metabolism. MSC secretome can be formally divided into secretory and vesicular parts, both of which are very important for intercellular communication and are involved in processes such as angiogenesis, proliferation, and immunomodulation. Exosomes are thought to have the same content and function as the MSCs from which they are derived, but they also have a number of advantages over stem cells, including low immunogenicity, unaltered functional activity during freezing and thawing, and a lack of tumor formation. In addition, MSC pre-treatment with various inflammatory factors or hypoxia can alter their secretomes so that it can be modified into a more effective treatment. Paracrine factors secreted by MSCs improve the survival of other cell populations by several mechanisms, including immunomodulatory (mostly anti-inflammatory) activity and anti-apoptotic activity partly based on Hsp27 upregulation. Reproductive medicine is one of the fields in which this cell-free approach has been extensively researched. This review presents the possible applications and challenges of using MSC secretome in the treatment of infertility. MSCs and their secretions have been shown to have beneficial effects in various models of female and male infertility resulting from toxic damage, endocrine disorders, trauma, infectious agents, and autoimmune origin.

Therapeutic effect of long-interval repeated subcutaneous administration of canine amniotic membrane-derived mesenchymal stem cells in atopic dermatitis mouse model

Atopic dermatitis (AD) is a chronic and inflammatory disease. According to a recent study, administration of canine MSCs is a potential therapy for immunological diseases. However, most related studies involve short-term experiments and acute atopic dermatitis animal models. Thus, studies of repeated subcutaneous injection of canine MSCs for ameliorating long-term inflammatory skin disorders have not yet been established. In this study, we evaluated the effects of long-term canine amniotic mesenchymal stem cells (cAM-MSCs) and calcineurin inhibitors (CNIs) treatments in mouse AD model for up to 8 weeks and compared the differences in therapeutic effect through canine peripheral blood mononuclear cells (PBMCs). Using a mouse model, we validated the therapeutic impact of cAM-MSCs in comparison to pimecrolimus (Pime), the most widely used CNIs, as a therapy for canine AD. Based on our results, we verified that the cAM-MSC treatment group exhibited substantially lower scores for tissue pathologic alterations, inflammatory cytokines, and dermatologic symptoms than the PBS control group. Importantly, compared with Pime, cAM-MSCs were more effective at preventing wound dysfunction and regulating mast cell activity. Additionally, we confirmed that immune modulation proteins (TGF-β1, IDO1, and COX-2) were increased in the cAM-MSCs treatment group. Furthermore, we examined the immunoregulatory effect of cAM-MSCs through the proliferation of T lymphocytes from activated canine PBMCs. As a result, cAM-MSCs suppressed the proliferative capacity of effector T cells from canine PBMCs more effectively than Pime. In conclusion, this study suggested that the cAM-MSCS could be an effective canine treatment for long-term canine AD through regeneration and immunomodulation.

Preclinical Evaluation of the Safety, Toxicity and Efficacy of Genetically Modified Wharton's Jelly Mesenchymal Stem/Stromal Cells Expressing the Antimicrobial Peptide SE-33

Mesenchymal stem/stromal cells (MSCs) offer promising therapeutic potential in cell-based therapies for various diseases. However, the safety of genetically modified MSCs remains poorly understood. This study aimed to evaluate the general toxicity and safety of Wharton's Jelly-Derived MSCs (WJ-MSCs) engineered to express the antimicrobial peptide SE-33 in an animal model. Genetically modified WJ-MSCs expressing SE-33 were administered to C57BL/6 mice at both therapeutic and excessive doses, either once or repeatedly. Animal monitoring included mortality, clinical signs, and behavioral observations. The toxicity assessment involved histopathological, hematological, and biochemical analyses of major organs and tissues, while immunotoxicity and immunogenicity were examined through humoral and cellular immune responses, macrophage phagocytic activity, and lymphocyte blast transformation. Antimicrobial efficacy was evaluated in a Staphylococcus aureus-induced pneumonia model by monitoring animal mortality and assessing bacterial load and inflammatory processes in the lungs. Mice receiving genetically modified WJ-MSCs exhibited no acute or chronic toxicity, behavioral abnormalities, or pathological changes, regardless of the dose or administration frequency. No significant immunotoxicity or alterations in immune responses were observed, and there were no notable changes in hematological or biochemical serum parameters. Infected animals treated with WJ-MSC-SE33 showed a significant reduction in bacterial load and lung inflammation and improved survival compared to control groups, demonstrating efficacy over native WJ-MSCs. Our findings suggest that WJ-MSCs expressing SE-33 are well tolerated, displaying a favorable safety profile comparable to native WJ-MSCs and potent antimicrobial activity, significantly reducing bacterial load, inflammation, and mortality in an S. aureus pneumonia model. These data support the safety profile of WJ-MSCs expressing SE-33 as a promising candidate for cell-based therapies for bacterial infections, particularly those complicated by antibiotic resistance.

Activation of angiopoietin-1 signaling with engineering mesenchymal stem cells promoted efficient angiogenesis in diabetic wound healing

BACKGROUND

Vascular insufficiency is associated with the pathogenesis and therapeutic outcomes of diabetic foot ulcers (DFU). While mesenchymal stem cells (MSCs) hold potential for DFU treatment, further enhancement in promoting angiogenesis in the challenging DFU wounds is imperative.

METHODS

The differential expression of pro- and anti-angiogenic factors during both normal and diabetic wound healing was compared using quantitative PCR. MSCs derived from the umbilical cord was prepared, and the engineered MSC (MSCANG1) overexpressing both the candidate pro-angiogenic gene, angiopoietin-1 (ANG1), and green fluorescent protein (GFP) was constructed using a lentiviral system. The pro-vascular stabilizing effects of MSCANG1 were assessed in primary endothelial cell cultures. Subsequently, MSCANG1 was transplanted into streptozotocin (STZ)-induced diabetic wound models to evaluate therapeutic effects on angiogenesis and wound healing. The underlying mechanisms were further examined both in vitro and in vivo.

RESULTS

The comprehensive analysis of the temporal expression of pro- and anti-angiogenic factors revealed a consistent impairment in ANG1 expression throughout diabetic wound healing. MSCANG1 exhibited robust EGFP expression in 80% of cells, with overexpression and secretion of the ANG1 protein. MSCANG1 notably enhanced the survival and tubulogenesis of endothelial cells and promoted the expression of junction proteins, facilitating the establishment of functional vasculature with improved vascular leakage. Although MSCANG1 did not enhance the survival of engrafted MSCs in diabetic wounds, it significantly promoted angiogenesis in diabetic wound healing, fostering the establishment of stable vasculature during the healing process. Activation of the protein kinase B (Akt) pathway and suppression of proto-oncogene tyrosine kinase Src (Src) activity in MSCANG1-treated diabetic wounds confirmed efficient angiogenesis process. Consequently, epidermal and dermal reconstruction, as well as skin appendage regeneration were markedly accelerated in MSCANG1-treated diabetic wounds compared to MSC-treated wounds.

CONCLUSION

Treatment with MSCs alone promotes angiogenesis and DFU healing, while the engineering of MSCs with ANG1 provides substantial additional benefits to this therapeutic process. The engineering of MSCs with ANG1 presents a promising avenue for developing innovative strategies in managing DFU.

Mesenchymal stem cells and mesenchymal stem cell-derived exosomes: a promising strategy for treating retinal degenerative diseases

Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic strategy in regenerative medicine, demonstrating significant potential for clinical applications. Evidence suggests that MSCs not only exhibit multipotent differentiation potential but also exert critical therapeutic effects in retinal degenerative diseases via robust paracrine mechanisms. MSCs protect retinal cells from degenerative damage by modulating inflammation, inhibiting apoptosis, alleviating oxidative stress, and suppressing cell death pathways. Furthermore, MSCs contribute to retinal structural and functional stability by facilitating vascular remodeling and donating mitochondria to retinal cells. Of particular interest, MSC-derived exosomes have gained widespread attention as a compelling cell-free therapy. Owing to their potent anti-inflammatory, anti-apoptotic, and vascular-stabilizing properties, exosomes show significant promise for the treatment of retinal degenerative diseases.

Emerging Role of Mesenchymal Stromal Cell and Exosome Therapies in Treating Cognitive Impairment

Cognitive aging, characterized by the gradual decline in cognitive functions such as memory, attention, and problem-solving, significantly impacts daily life. This decline is often accelerated by neurodegenerative diseases, particularly Alzheimer's Disease (AD) and Parkinson's Disease (PD). AD is marked by the accumulation of amyloid-beta plaques and tau tangles, whereas PD involves the degeneration of dopaminergic neurons. Both conditions lead to severe cognitive impairment, greatly diminishing the quality of life for affected individuals. Recent advancements in regenerative medicine have highlighted mesenchymal stromal cells (MSCs) and their derived exosomes as promising therapeutic options. MSCs possess regenerative, neuroprotective, and immunomodulatory properties, which can promote neurogenesis, reduce inflammation, and support neuronal health. Exosomes, nanosized vesicles derived from MSCs, provide an efficient means for delivering bioactive molecules across the blood-brain barrier, targeting the underlying pathologies of AD and PD. While these therapies hold great promise, challenges such as variability in MSC sources, optimal dosing, and effective delivery methods need to be addressed for clinical application. The development of robust protocols, along with rigorous clinical trials, is crucial for validating the safety and efficacy of MSC and exosome therapies. Future research should focus on overcoming these barriers, optimizing treatment strategies, and exploring the integration of MSC and exosome therapies with lifestyle interventions. By addressing these challenges, MSC- and exosome-based therapies could offer transformative solutions for improving outcomes and enhancing the quality of life for individuals affected by cognitive aging and neurodegenerative diseases.

Secretome Analysis of Human and Rat Pancreatic Islets Co-Cultured with Adipose-Derived Stromal Cells Reveals a Signature with Enhanced Regenerative Capacities

Pancreatic islet transplantation (PIT) is a promising treatment for type 1 diabetes (T1D) but faces challenges pre- and post-transplantation. Co-transplantation with mesenchymal stromal cells (MSCs), known for their regenerative properties, has shown potential in improving PIT outcomes. This study examined the secretome of islets cultured alone compared to the secretomes of islets co-cultured with adipose-derived stromal cells (ASCs), a subtype of MSCs, under transplantation-relevant stressors: normoxia, cytokines, high glucose, hypoxia, and combined hypoxia and high glucose. Islet co-culture with ASCs significantly altered the proteome, affecting pathways related to energy metabolism, angiogenesis, extracellular matrix organization, and immune modulation. Key signaling molecules (e.g., VEGF, PDGF, bFGF, Collagen I alpha 1, IL-1α, and IL-10) were differentially regulated depending on culture conditions and ASC presence. Functional assays demonstrated that the co-culture secretome could enhance angiogenesis, collagen deposition, and immune modulation, depending on the stress conditions. These findings highlight possible mechanisms through which ASCs may support islet survival and function, offering insights into overcoming PIT challenges. Moreover, this work contributes to identifying biomarkers of the post-transplantation microenvironment, advancing therapeutic strategies for T1D and regenerative medicine.

Cerebral Small Vessel Disease: Current and Emerging Therapeutic Strategies

Cerebral small vessel disease (CSVD) is a common disease in older people, characterized by damage to intracranial microvessels, leading to cognitive decline, increased risk of stroke, and dementia. This review reviews the current therapeutic approaches for CSVD and the latest research advances, encompassing traditional pharmacological therapies, emerging targeted interventions grounded in pathophysiology, exploratory immune-related treatments, and advances in genetic research. In addition, the role of lifestyle modifications in disease management is discussed. The review emphasizes the importance of a holistic, personalized treatment strategy to improve outcomes. More clinical trials are needed to validate these treatments and optimize individualized treatment options for CSVD patients.

Improving the therapeutic profile of MSCs: Cytokine priming reduces donor-dependent heterogeneity and enhances their immunomodulatory capacity

Introduction

MSCs exhibit regenerative, anti-inflammatory and immunomodulatory properties due to the large amount of cytokines, chemokines and growth factors they secrete. MSCs have been extensively evaluated in clinical trials, however, in some cases their therapeutic effects are variable. Therefore, strategies to improve their therapeutic potential, such as preconditioning with proinflammatory factors, have been proposed. Several priming approaches have provided non-conclusive results, and the duration of priming effects on MSC properties or their response to a second inflammatory stimulus have not been fully addressed.

Methods

We have investigated the impact of triple cytokine priming in MSCs on their characterization and viability, their transcriptomic profile, the functionality of innate and acquired immune cells, as well as the maintenance of the response to priming over time, their subsequent responsiveness to a second inflammatory stimulus.

Results

Priming MSCs with proinflammatory cytokines (CK-MSCs) do not modify the differentiation capacity of MSCs, nor their immunophenotype and viability. Moreover, cytokine priming enhances the anti-inflammatory and immunomodulatory properties of MSCs against NK and dendritic cells, while maintaining the same T cell immunomodulatory capacity as unstimulated MSCs. Thus, they decrease T-lymphocytes and NK cell proliferation, inhibit the differentiation and allostimulatory capacity of dendritic cells and promote the differentiation of monocytes with an immunosuppressive profile. In addition, we have shown for the first time that proinflammatory priming reduces the variability between different donors and MSC origins. Finally, the effect on CK-MSC is maintained over time and even after a secondary inflammatory stimulus.

Conclusions

Cytokine-priming improves the therapeutic potential of MSCs and reduces inter-donor variability.

Gingival fibroblast suppress the osteogenesis process mediated by bone substitute materials via WNT/β-catenin signaling pathway in vitro and in vivo

Background

The regeneration of bone tissue is a critical challenge in oral and maxillofacial surgery, with the success of such procedures often depending on the ability to promote osteogenesis while managing the soft tissue environment. The role of gingival fibroblasts in modulating the osteogenic potential of mandible mesenchymal stem cells (MMSCs) mediated by bone substitute materials (BSMs) is not fully understood. This study aimed to investigate the impact of gingival fibroblasts on the osteogenic differentiation of MSCs in the presence of BSMs and to elucidate the underlying mechanisms, focusing on the WNT/β-catenin signaling pathway.

Methods

Gingival fibroblasts and BSMs co-culture conditioned medium was used to culture MMSCs, and the expression and activity of alkaline phosphatase (ALP), as well as osteogenic and fibrogenic gene and protein expression, were evaluated. Additionally, the expression of key factors of WNT/β-catenin signaling pathway were investigated. In vivo animal experiments were conducted to assess the effect of gingival fibroblasts on BSM-mediated bone regeneration.

Results

Gingival fibroblasts and BSMs co-culture environment did not affect MMSCs proliferation but significantly inhibited ALP expression and activity, as well as osteogenic gene and protein expression, while promoting expression of fibrogenic markers. This suppression was associated with the downregulation of key factors in the WNT/β-catenin signaling pathway. In vivo, increased suppression of bone defect repair was observed with higher amounts of gingival fibroblasts, confirming the in vitro findings.

Conclusion

Our study demonstrates that gingival fibroblasts can suppress the osteogenic potential of BSMs by inhibiting the autocrine WNT expression and the activation of the WNT/β-catenin signaling pathway in MMSCs. These findings highlight the importance of considering the cellular microenvironment in tissue engineering and regenerative medicine and suggest potential targets for modulating MMSCs behavior to enhance bone regeneration.

Paracrine activity of Smurf1-silenced mesenchymal stem cells enhances bone regeneration and reduces bone loss in postmenopausal osteoporosis

BACKGROUND

Osteoporosis (OP), characterized by reduced bone mass and mineral density, is a global metabolic disorder that severely impacts the quality of life in affected individuals. Although current pharmacological treatments are effective, their long-term use is often associated with adverse effects, highlighting the need for safer, more sustainable therapeutic strategies. This study investigates the pro-osteogenic and anti-resorptive potential of the secretome from Smurf1-silenced mesenchymal stem cells (MSCs) as a promising cell-free therapy for bone regeneration.

METHODS

Conditioned media (CM) from Smurf1-silenced rat (rCM-Smur1) and human MSCs (hCM-Smurf1) was collected and analyzed. Pro-osteogenic potential was assessed by measuring in vitro mineralization in human and rat MSCs cultures. In vivo, studies were conducted using a rat ectopic bone formation model and a post-menopausal osteoporotic mouse model. Additionally, primary human osteoporotic MSCs were preconditioned with hCM-Smurf1, and their osteogenic capacity was compared to that induced by BMP2 treatment. Ex vivo, human bone explants were treated with hCM-Smurf1 to assess anti-resorptive effects. Proteomic analysis of the soluble and vesicular CM fractions identified key proteins involved in bone regeneration.

RESULTS

CM from Smurf1-silenced MSCs significantly enhanced mineralization in vitro and bone formation in vivo. Preconditioning human osteoporotic MSCs with hCM-Smurf1 significantly increases in vitro mineralization, with levels comparable to those achieved with BMP2 treatment. Additionally, in ex vivo human bone cultures, treatment with hCM-Smurf1 significantly reduced RANKL expression without affecting OPG levels, indicating an anti-resorptive effect. In vivo, CM from Smurf1-silenced MSCs significantly increased bone formation in a rat ectopic model, and its local administration reduced trabecular bone loss by 50% in a post-menopausal osteoporotic mouse model after a single administration within just four weeks. Proteomic analysis revealed both soluble and vesicular fractions of hCM-Smurf1 were enriched with proteins essential for ossification and extracellular matrix organization, enhancing osteogenic differentiation.

CONCLUSIONS

The Smurf1-silenced MSCs' secretome shows potent osteogenic and anti-resorptive effects, significantly enhancing bone formation and reducing bone loss. This study provides compelling evidence for the therapeutic potential of Smurf1-silenced MSC-derived secretome as a non-toxic and targeted treatment for osteoporosis. These findings warrant further in vivo studies and clinical trials to validate its therapeutic efficacy and safety.

Nasal mucosal mesenchymal stem cells promote repair of sciatic nerve injury in rats by modulating the inflammatory microenvironment

Sciatic nerve injury (SNI) represents the most prevalent form of peripheral nerve damage, resulting in the rapid activation of macrophages into the M1 phenotype following injury. This activation induces an inflammatory microenvironment that negatively impacts nerve regeneration. Ectodermal mesenchymal stem cells (EMSCs), isolated from nasal mucosa, possess the capacity for multidirectional differentiation and exhibit immunomodulatory effects. Modulating macrophage polarization to create a favorable environment for nerve repair may represent a potential approach to facilitate nerve recovery. This investigation sought to explore the effects of EMSCs transplantation on macrophage polarization and nerve regeneration in SNI, as well as to identify the underlying mechanisms. An in vivo SNI model was established, and behavioral and histological analyses demonstrated that EMSCs transplantation facilitated nerve function recovery. Furthermore, immunofluorescence and Western blot assays revealed an increase in M2 macrophage presence and the secretion of anti-inflammatory cytokines following EMSCs transplantation, thereby promoting nerve regeneration. In vitro, EMSCs were found to enhance M2 macrophage polarization and the production of anti-inflammatory factors. Additionally, it was confirmed that EMSCs regulate macrophage polarization through the PI3K/AKT/NF-κB signaling pathway, thereby fostering an optimal inflammatory environment for nerve regeneration.

Mesenchymal stem cells and their extracellular vesicle therapy for neurological disorders: traumatic brain injury and beyond

Traumatic brain injury (TBI) is a complex condition involving mechanisms that lead to brain dysfunction and nerve damage, resulting in significant morbidity and mortality globally. Affecting ~50 million people annually, TBI's impact includes a high death rate, exceeding that of heart disease and cancer. Complications arising from TBI encompass concussion, cerebral hemorrhage, tumors, encephalitis, delayed apoptosis, and necrosis. Current treatment methods, such as pharmacotherapy with dihydropyridines, high-pressure oxygen therapy, behavioral therapy, and non-invasive brain stimulation, have shown limited efficacy. A comprehensive understanding of vascular components is essential for developing new treatments to improve blood vessel-related brain damage. Recently, mesenchymal stem cells (MSCs) have shown promising results in repairing and mitigating brain damage. Studies indicate that MSCs can promote neurogenesis and angiogenesis through various mechanisms, including releasing bioactive molecules and extracellular vesicles (EVs), which help reduce neuroinflammation. In research, the distinctive characteristics of MSCs have positioned them as highly desirable cell sources. Extensive investigations have been conducted on the regulatory properties of MSCs and their manipulation, tagging, and transportation techniques for brain-related applications. This review explores the progress and prospects of MSC therapy in TBI, focusing on mechanisms of action, therapeutic benefits, and the challenges and potential limitations of using MSCs in treating neurological disorders.

Proteomic profiling of iPSC and tissue-derived MSC secretomes reveal a global signature of inflammatory licensing

Much of the therapeutic potential of mesenchymal stromal cells (MSCs) is underpinned by their secretome which varies significantly with source, donor and microenvironmental cues. Understanding these differences is essential to define the mechanisms of MSC-based tissue repair and optimise cell therapies. This study analysed the secretomes of bone-marrow (BM.MSCs), umbilical-cord (UC.MSCs), adipose-tissue (AT.MSCs) and clinical/commercial-grade induced pluripotent stem cell-derived MSCs (iMSCs), under resting and inflammatory licenced conditions. iMSCs recapitulated the inflammatory licensing process, validating their comparability to tissue-derived MSCs. Overall, resting secretomes were defined by extracellular matrix (ECM) and pro-regenerative proteins, while licensed secretomes were enriched in chemotactic and immunomodulatory proteins. iMSC and UC.MSC secretomes contained proteins indicating proliferative potential and telomere maintenance, whereas adult tissue-derived secretomes contained fibrotic and ECM-related proteins. The data and findings from this study will inform the optimum MSC source for particular applications and underpin further development of MSC therapies.

Odontogenic differentiation of dental pulp stem cells by glycogen synthase kinase-3β inhibitory peptides

BACKGROUND

To investigate the effects of peptide-based substrate competitive inhibitors of GSK-3β (GSK-3βi) on promoting odontogenic differentiation of human dental pulp stem cells (hDPSCs).

METHODS

The biocompatibility and proliferation of hDPSCs treated with GSK-3βi peptides (pS9, LRP 6a, L803, and L803-mts) were evaluated using the tetrazolium reduction assay and cell counting kit-8 assay, respectively. The differentiation of hDPSCs following peptide treatment was determined using the alkaline phosphatase assay (ALP), calcium mineralization (alizarin red staining), and quantification of mRNA expression of differentiation markers via quantitative real-time polymerase chain reaction. The accumulation of β-catenin in the nucleus of GSK3-βi-treated hDPSCs was determined using immunofluorescence staining. The effect of peptide treatment on hDPSC migration was characterized using the transwell assay.

RESULTS

All tested concentrations of the peptides were found to be biocompatible with the hDPSCs, with no significant difference compared to the control (p > 0.05). The peptides had no effect on the proliferation of hDPSCs compared to the control (p > 0.05). However, all the tested peptides significantly increased ALP activity and calcium deposition in a dose-dependent manner (p < 0.05). Specifically, L803-mts showed significantly greater ALP activity and mineralization compared to the other peptides and the controls (p < 0.05). Additionally, L803-mts showed a significant increase (p < 0.05) in the expression of DSPP, DMP-1, Runx-2, along with increased protein expression of DSPP and DMP-1 compared to the control. Furthermore, it enhanced the nuclear translocation of β-catenin and increased the chemotactic migratory potential of hDPSCs.

CONCLUSIONS

L803-mts, a peptide-based substrate competitive inhibitor of GSK-3β, enhanced the odontogenic differentiation of hDPSCs by activating the Wnt signaling pathway.

Therapeutic potential of mesenchymal stem cell-derived extracellular vesicles in ischemic stroke: A meta-analysis of preclinical studies

BACKGROUND

Ischemic stroke (IS) remains a significant global health burden, necessitating the development of novel therapeutic strategies. This study aims to systematically evaluate the therapeutic effects of mesenchymal stem cell-derived exosomes (MSC-Exos) on IS outcomes in rodent models.

METHODS

A comprehensive literature search was conducted across multiple databases to identify studies investigating the effects of MSC-Exos on rodent models of IS. Following rigorous inclusion and exclusion criteria, 73 high-quality studies were selected for meta-analysis. Primary outcomes included reductions in infarct volume/ratio and improvements in functional recovery scores. Data extraction and analysis were performed using RevMan 5.3 software.

RESULTS

Pooled data indicated that MSC-Exos administration significantly reduced infarct size and improved functional recovery scores in rodent models of IS. Treatment within 24 hours and beyond 24 hours of stroke induction both demonstrated substantial reductions in infarct volume/ratio compared to controls. Furthermore, MSC-Exos-treated groups exhibited marked improvements in functional recovery, as assessed by various neurobehavioral tests. The meta-analysis showed no significant publication bias, and heterogeneity levels were acceptable.

CONCLUSIONS

MSC-Exos reveal significant therapeutic potential for IS, with evidence supporting their efficacy in reducing infarct size and enhancing functional recovery in preclinical rodent models. These findings pave the way for further research and potential clinical translation.

Efficacy of a single dose of cryopreserved human umbilical cord mesenchymal stromal cells for the treatment of knee osteoarthritis:a randomized, controlled, double-blind pilot study

BACKGROUND

Knee osteoarthritis (OA) is the most prevalent degenerative musculoskeletal disorder, which is particularly common in older population. While conventional treatments have limited effectiveness, the development of more effective therapeutic strategies is necessary to address this primary source of pain and disability. Umbilical cord mesenchymal stromal cells (UC-MSCs) offer a promising therapeutic approach for treating knee OA.

AIM

This randomized, prospective, double-blind and controlled pilot study was carried out to evaluate and compare the safety and therapeutic efficacy of a single intra-articular injection of a standardized product CellistemOA (5 × 106 ± 5 × 105 UC-MSCs), vs. triamcinolone (a synthetic corticosteroid) (10 mg/mL) in thirty patients with symptomatic knee OA (Kellgren-Lawrence grade II or III).

METHODS

The outcomes included changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores based on a Likert scale, numerical rating score (NRS) for pain, Magnetic Resonance Imaging (MRI), and quality of life (SF-36 questionnaire), from baseline and throughout 12-months of follow-up.

RESULTS

Patients treated with CellistemOA showed significant improvement in WOMAC score (including the three subscale scores (pain, stiffness and function), NRS in pain, and SF-36 profile from baseline to 12 months (p < 0.05) compared to the triamcinolone group, and no severe adverse events were reported. There were no significant differences in MRI WORMS scores between the two groups. However, patients who received the cellular treatment experienced a significant improvement in their SF-36 profile (p < 0.05).

CONCLUSIONS

This pilot study revealed that a single dose of CellistemOA is safe and superior to the active comparator in knee OA at 1-year of follow-up, making it a compelling therapeutic alternative to treat symptomatic OA patients.

Single-cell transcriptomic sequencing analysis of mechanistic insights into the IFN-γ signaling pathway in different tumor cells

PURPOSE

This study aimed to investigate the relationship between the interferon-gamma (IFN-γ) pathway in different tumor microenvironments (TME) and patients' prognosis, as well as the regulatory mechanisms of this pathway in tumor cells.

METHODS

Using RNA-seq data from the TCGA database, we analyzed the predictive value of the IFN-γ pathway across various tumors. We employed a univariate Cox regression model to assess the prognostic significance of IFN-γ signaling in different tumor types. Additionally, we analyzed single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database to examine the distribution characteristics of the IFN-γ pathway and explore its regulatory mechanisms, highlighting how IFN-γ influenced cellular interactions within the TME.

RESULTS

Our analysis revealed a significant association between the IFN-γ pathway and adverse prognosis in pan-cancer tissues (P < 0.001). Interestingly, this correlation varied regarding positive and negative regulation across different tumor types. Through a detailed examination of scRNA-seq data, we found that the IFN-γ pathway exerted substantial regulatory effects on stromal and immune cells. In contrast, its expression and regulatory patterns in tumor cells exhibited diversity and heterogeneity. Further analysis indicated that the IFN-γ pathway not only enhanced the immunogenicity of tumor cells but also inhibited their proliferation. Cell-cell interaction analysis confirmed the pivotal role of the IFN-γ pathway within the overall regulatory network. Moreover, we identified HMGB2 (high mobility group box 2) in T cells as a potential key regulator of tumor cell proliferation.

CONCLUSIONS

The IFN-γ pathway exhibited a dual function by both suppressing tumor cell proliferation and enhancing their immunogenicity, positioning it as a pivotal target for refined cancer diagnosis and cancer strategies.

Low-energy electric shock ameliorates cell proliferation, morphallaxis, and regeneration via driving key regenerative proteins in earthworm and 3T3 cells

Electric stimulation regulates many cellular processes like cell proliferation, differentiation, apoptosis and cellular migration. Despite its crucial role in regulating stem cells and regeneration, it remains underexplored in both in-vivo and in-vitro settings. In this study, Eudrilus eugeniae are subjected to electric stimulation (1.5 V) prior and after amputation and which augments regeneration up to double-time. Blocking epimorphosis using 2 M thymidine retracts regeneration kinetics to one-third but such inhibition was rescued by applying electric stimulation which propels an overactive morphallaxis pattern of regeneration. Excreting electric stimulation on control worms shows minimal impact, whereas it enhances the key regenerative proteins like VEGF, COX2, YAP, c-Myc, and Wnt3a on amputated worms. Upon blocking epimorphosis, all these key regenerative proteins are down-regulated but through electric stimulation, the cells are reprogrammed to express a triple fold of the mentioned regenerative proteins, that further promotes morphallaxis. In 3T3 cells, electric stimulation accelerates cell proliferation and migrations in 5 secs exposure and it exerts its function by overexpressing VEGF mediated by MEK1. Wnt3a expression was gradually upregulated in increasing exposure (5 and 25 secs) which aids in maintaining the stemness property. The molecular mechanism underlying regeneration capability can assist in designing novel therapeutic applications.

Application of novel strategies in chronic wound management with focusing on pressure ulcers: new perspective

Invading blood cells, extracellular tissue, and soluble mediators all play important roles in the wound-healing process. There is a substantial global burden of disease and mortality attributable to skin defects that do not heal. About 1% to 2% of the population in industrialized nations suffers from chronic wounds that don't heal, despite healthcare breakthroughs; this condition is very costly, costing about $25 billion each year in the US alone. Amputation, infection (affecting as many as 25% of chronic wounds), sepsis, and dermal replacements are all consequences of conventional therapeutic approaches like growth factor therapy and diabetic foot ulcers account for 85% of lower limb amputations. Despite these obstacles, scientists are constantly looking for new ways to speed healing and close wounds. The unique immunomodulatory capabilities and multipotency of mesenchymal stem cells (MSCs) have made them a potential therapeutic choice in tissue engineering and regenerative medicine. Animal models of wound healing have shown that MSCs can speed up the process by as much as 40% through enhancing angiogenesis, modulating inflammation, and promoting fibroblast migration. Clinical trials provide more evidence of their effectiveness; for instance, one RCT found that, after 12 weeks, patients treated with MSCs had a 72% smaller wound size than those in the control group. This review offers a thorough examination of MSCs by combining the latest research with preclinical evidence. Highlighting their potential to transform treatment paradigms, it delves into their biological properties, how they work during regeneration and healing, and therapeutic usefulness in controlling chronic wounds.

Bone marrow mesenchymal stem cells promote uterine healing by activating the PI3K/AKT pathway and modulating inflammation in rat models

BACKGROUND

Uterine injury can cause uterine scarring, leading to a series of complications that threaten women's health. Uterine healing is a complex process, and there are currently no effective treatments. Although our previous studies have shown that bone marrow mesenchymal stem cells (BMSCs) promote uterine damage repair, the underlying mechanisms remain unclear. However, exploring the specific regulatory roles of BMSCs in uterine injury treatment is crucial for further understanding their functions and enhancing therapeutic efficacy.

AIM

To investigate the underlying mechanism by which BMSCs promote the process of uterine healing.

METHODS

In in vivo experiments, we established a model of full-thickness uterine injury and injected BMSCs into the uterine wound. Transcriptome sequencing was performed to determine the enrichment of differentially expressed genes at the wound site. In in vitro experiments, we isolated rat uterine smooth muscle cells (USMCs) and cocultured them with BMSCs to observe the interaction between BMSCs and USMCs in the microenvironment.

RESULTS

We found that the differentially expressed genes were mainly related to cell growth, tissue repair, and angiogenesis, while the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was highly enriched. Quantitative reverse-transcription polymerase chain reaction was used to validate differentially expressed genes, and the results demonstrated that BMSCs can upregulate genes related to regeneration and downregulate genes related to inflammation. Coculturing BMSCs promoted the migration and proliferation of USMCs, and the USMC microenvironment promoted the myogenic differentiation of BMSCs. Finally, we validated the PI3K/AKT pathway in tissues and cells and showed that BMSCs activate the PI3K/AKT pathway to promote the regeneration of uterine smooth muscle both in vivo and in vitro.

CONCLUSION

BMSCs upregulated uterine wound regeneration and anti-inflammatory factors and enhanced uterine smooth muscle proliferation through the PI3K/AKT pathway both in vivo and in vitro.

Role of Kynurenine and Its Derivatives in Liver Diseases: Recent Advances and Future Clinical Perspectives

Liver health is integral to overall human well-being and the pathogenesis of various diseases. In recent years, kynurenine and its derivatives have gradually been recognized for their involvement in various pathophysiological processes, especially in the regulation of liver diseases, such as acute liver injury, non-alcoholic fatty liver disease, cirrhosis, and liver cancer. Kynurenine and its derivatives are derived from tryptophan, which is broken down by the enzymes indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO), converting the essential amino acid tryptophan into kynurenine (KYN) and other downstream metabolites, such as kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), xanthurenic acid (XA), and quinolinic acid (QA). In liver diseases, kynurenine and its derivatives can promote the activity of the transcription factor aryl hydrocarbon receptor (AhR), suppress T cell activity for immune modulation, inhibit the activation of inflammatory signaling pathways, such as NF-κB for anti-inflammatory effects, and inhibit the activation of hepatic stellate cells to slow down fibrosis progression. Additionally, kynurenine and other downstream metabolites can influence the progression of liver diseases by modulating the gut microbiota. Therefore, in this review, we summarize and explore the mechanisms by which kynurenine and its derivatives regulate liver diseases to help develop new diagnostic or prognostic biomarkers and effective therapies targeting the kynurenine pathway for liver disease treatment.

Bone marrow mesenchymal stem cells derived cytokines associated with AKT/IAPs signaling ameliorate Alzheimer's disease development

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative condition affecting around 50 million people worldwide. Bone marrow-derived mesenchymal stem cells (BMMSCs) have emerged as a promising source for cellular therapy due to their ability to differentiate into multiple cell types and their paracrine effects. However, the direct injection of BMMSCs can lead to potential unpredictable impairments, prompting a renewed interest in their paracrine effects for AD treatment. The specific mechanism and central role of cytokines in this process have not been fully elucidated.

METHODS

Mouse BMMSCs were isolated, validated, and then transplanted intracerebrally into APP/PS1 female mice. The behavioral tests, including open-field test, novel object recognition test, and Morris water maze were performed, followed by β-amyloidosis plaque and neuron apoptosis analyses. Then the tissue RNA sequencing and mBMMSC cytokine analysis were performed. A cytokine antibody array for BMMSCs and the brain slice models were performed with AD model tissues were used to elucidate the molecular mechanisms. Finally, APP/PS1 mice were administrated with cytokine mixture for cognitive recovery.

RESULTS

Our results demonstrated that BMMSCs significantly improved cognitive function, reduced beta-amyloid plaque deposition, and decreased apoptotic neurons through the activation of the AKT signaling pathway. Using a cytokine antibody array, we identified three highly expressed AKT pathway regulated neuroprotective factors in BMMSCs: IGF1, VEGF, and Periostin2. These cytokines were found to upregulate inhibitors of apoptosis family proteins (IAPs) and suppress Caspase-3 activity in brain slices induced with beta amyloidosis (Aβ), okadaic acid (OA), and lipopolysaccharide (LPS). When injection of this cytokine mixture to APP/PS1 mice also resulted in a mitigation of cognitive impairment.

CONCLUSIONS

These findings suggest that the secretory factors IGF1, VEGF, and Periostin2 derived from BMMSCs play a crucial role in neuroprotection by modulating the AKT/IAPs pathway to restore neuronal function. These cytokine sets could be a potential therapeutic strategy for AD and lay the groundwork for promising clinical applications.

Decoding Cytokine Dynamics: Wharton's Jelly Stromal Cells and Chondro-Differentiates in PHA-Stimulated Co-Culture

INTRODUCTION

Articular cartilage damage presents a significant clinical challenge, with limited options for effective regeneration. Mesenchymal stromal cells (MSCs) derived from Wharton's jelly (WJ) are a promising cell source for cartilage repair due to their regenerative and immunomodulatory properties. While undifferentiated MSCs have demonstrated potent immunoregulatory effects, the immunomodulatory potential of chondrocytes derived from WJ-MSCs remains underexplored, particularly under inflammatory conditions. This study investigates the differential cytokine expression profiles of WJ-MSC-derived chondrocytes and undifferentiated MSCs under inflammatory stimulation with phytohemagglutinin (PHA) to understand their immunomodulatory capacities.

MATERIALS AND METHODS

WJ-MSCs were differentiated into chondrocytes using a micromass culture system. Differentiated chondrocytes were then co-cultured with immune cells under PHA-induced inflammatory conditions. Control groups included co-cultured cells without PHA activation and chondrocytes activated with PHA in the absence of immune cell interaction. Cytokine expression profiles were analyzed using the RT2 Customized Gene Array to evaluate pro- and anti-inflammatory markers. Morphological changes were assessed microscopically. The immunomodulatory responses of chondrocytes were compared to those of undifferentiated MSCs under the same experimental conditions.

RESULTS

Chondrocytes co-cultured with immune cells under PHA activation exhibited downregulation of IDO, HLA-G, PDGF, IL-10, TNF-α, IL-6, and IFN-γ compared to undifferentiated MSCs in similar conditions. In non-PHA co-cultured conditions, chondrocytes showed increased expression of IL-6, IFN-γ, IL-4, VEGF, iNOS, PDGF, PTGS-2 and TGF-β, while TNF-α, IL-10, IDO and HLA-G were decreased. In contrast, chondrocytes activated with PHA without immune cell interaction displayed reduced expression of HLA-G and TNF-α, with no significant changes in IL-6, IFN-γ, IL-4, IL-10, VEGF, PDGF, PTGS-2, TGF-β, IDO, and iNOS compared to PHA-stimulated undifferentiated MSCs.

CONCLUSION

This study demonstrates that chondrocytes derived from WJ-MSCs exhibit limited immunomodulatory potential compared to undifferentiated MSCs, particularly under PHA-induced inflammatory conditions. Undifferentiated MSCs showed superior regulation of key cytokines associated with immune modulation. These findings suggest that maintaining MSCs in an undifferentiated state may be advantageous for therapeutic applications targeting inflammatory conditions, such as osteoarthritis. Future research should explore strategies to enhance the immunomodulatory efficacy of chondrocytes, potentially through genetic modification or adjunctive therapies.

Functional heterogeneity of mesenchymal stem cells and their therapeutic potential in the K18-hACE2 mouse model of SARS-CoV-2 infection

BACKGROUND

Despite many years of investigation into mesenchymal stem cells (MSCs) and their potential for treating inflammatory conditions such as COVID-19, clinical outcomes remain variable due to factors like donor variability, different tissue sources, and diversity within MSC populations. Variations in MSCs' secretory and proliferation profiles, and their proteomic and transcriptional characteristics significantly influence their therapeutic potency, highlighting the need for enhanced characterization methods to better predict their efficacy. This study aimed to evaluate the biological characteristics of MSCs from different tissue origins, selecting the most promising line for further validation in a K18-hACE2 mouse model of SARS-CoV-2 infection.

METHODS

We studied nine MSC lines sourced from either bone marrow (hBMMSC), dental pulp (hDPMSC), or umbilical cord tissue (hUCMSC). The cells were assessed for their proliferative capacity, immunophenotype, trilineage differentiation, proteomic profile, and in vitro immunomodulatory potential by co-culture with activated lymphocytes. The most promising MSC line was selected for further experimental validation using the K18-hACE2 mouse model of SARS-CoV-2 infection.

RESULTS

The analyzed cells met the minimum criteria for defining MSCs, including the expression of surface molecules and differentiation capacity, showing genetic stability and proliferative potential. Proteomic analysis revealed distinct protein profiles that correlate with the tissue origin of MSCs. The immunomodulatory response exhibited variability, lacking a discernible pattern associated with their origin. In co-culture assays with lymphocytes activated with anti-CD3/CD28 beads, all MSC lines demonstrated the ability to inhibit TNF-α, to induce TGF-β and Indoleamine 2,3-dioxygenase (IDO), with varying degrees of inhibition observed for IFN-γ and IL-6, or induction of IL-10 expression. A module of proteins was found to statistically correlate with the potency of IL-6 modulation, leading to the selection of one of the hUCMSCs as the most promising line. Administration of hUCMSC to SARS-CoV-2-infected K18 mice expressing hACE2 was effective in improving lung histology and modulating of a panel of cytokines.

CONCLUSIONS

Our study assessed MSCs derived from various tissues, uncovering significant variability in their characteristics and immunomodulatory capacities. Particularly, hUCMSCs demonstrated potential in mitigating lung pathology in a SARS-CoV-2 infection model, suggesting their promising therapeutic efficacy.

Unveiling the signal valve specifically tuning the TGF-β1 suppression of osteogenesis: mediation through a SMAD1-SMAD2 complex

BACKGROUND

TGF-β1 is the most abundant cytokine in bone, in which it serves as a vital factor to interdict adipogenesis and osteogenesis of bone marrow-derived mesenchymal stem cells (BM-MSCs). However, how TGF-β1 concurrently manipulates differentiation into these two distinct lineages remains elusive.

METHODS

Treatments with ligands or inhibitors followed by biochemical characterization, reporter assay, quantitative PCR and induced differentiation were applied to MSC line or primary BM-MSCs for signaling dissection. In vivo adipogenesis and ex vivo culture of bone explants were used to verify the functions of different SMAD complexes. Ingenuity Pathway Analysis, and analysis of transcriptomic datasets from human BM-MSCs in combination with hierarchical clustering and STRING assay were used to decipher the interplaying co-repressors. Mouse models of chronic and acute bone loss followed by biochemical assays and micro-computed tomography demonstrated the bone effects when functionally blocking the critical co-repressor HDAC1.

RESULTS

Distinct from the TGF-β1 inhibition on adipogenesis through canonical SMAD2/3 signaling, we clarified that TGF-β1 suppresses osteogenesis by inducing the formation of previously unidentified mixed SMADs mainly composed of SMAD1 and SMAD2, in which SMAD2 recruits more TGF-β1-induced co-repressors including HDAC1, TGIF1 and ATF3, whereas SMAD1 allows directing the whole transcriptional suppression complex to the cis-elements of osteogenic genes. Depletion of the cross-activation to the mixed SMADs dismantled specifically the TGF-β1 suppression on osteogenesis without affecting its inhibition on adipogenesis. Such phenomena can be reproduced via knockdown of co-repressors such as Hdac1 or addition of HDAC1 inhibitors in TGF-β1-treated MSCs. In either the chronic or the acute bone loss model, we demonstrated that the TGF-β signaling was augmented in the bone niche during osteolysis, whereas administration of HDAC1 inhibitors significantly improved bone quality.

CONCLUSION

This study identifies a new signal valve through which TGF-β1 can inhibit osteogenesis specifically. Functional interruption of this valve can tilt the seesaw balance of BM-MSC differentiation towards osteogenesis, highlighting the interplaying co-repressors, such as HDAC1, as promising therapeutic targets to combat diverse degenerative orthopedic diseases.