BACKGROUND: The effects of human umbilical cord-derived mesenchymal stem cell (UC-MSC) treatment on coronavirus disease 2019 (COVID-19) patients have been preliminarily characterized. However, real-world data on the safety and efficacy of intravenous transfusions of MSCs in hospitalized COVID-19 patients at the convalescent stage remain to be reported. METHODS: This was a single-arm, multicenter, real-word study in which a contemporaneous external control was included as the control group. Besides, severe and critical COVID-19 patients were considered together as the severe group, given the small number of critical patients. For a total of 110 patients, 21 moderate patients and 31 severe patients were enrolled in the MSC treatment group, while 26 moderate patients and 32 severe patients were enrolled in the control group. All patients received standard treatment. The MSC treatment patients additionally received intravenous infusions of MSCs at a dose of 4 × 10 7 cells on days 0, 3, and 6, respectively. The clinical outcomes, including adverse events (AEs), lung lesion proportion on chest computed tomography, pulmonary function, 6-min walking distance (6-MWD), clinical symptoms, and laboratory parameters, were measured on days 28, 90, 180, 270, and 360 during the follow-up visits. RESULTS: In patients with moderate COVID-19, MSC treatment improved pulmonary function parameters, including forced expiratory volume in the first second (FEV1) and maximum forced vital capacity (VCmax) on days 28 (FEV1, 2.75 [2.35, 3.23] vs . 2.11 [1.96, 2.35], P  = 0.008; VCmax, 2.92 [2.55, 3.60] vs . 2.47 [2.18, 2.68], P  = 0.041), 90 (FEV1, 2.93 [2.63, 3.27] vs . 2.38 [2.24, 2.63], P  = 0.017; VCmax, 3.52 [3.02, 3.80] vs . 2.59 [2.45, 3.15], P  = 0.017), and 360 (FEV1, 2.91 [2.75, 3.18] vs . 2.30 [2.16, 2.70], P  = 0.019; VCmax,3.61 [3.35, 3.97] vs . 2.69 [2.56, 3.23], P  = 0.036) compared with the controls. In addition, in severe patients, MSC treatment notably reduced the proportion of ground-glass lesions in the whole lung volume on day 90 ( P  = 0.045) compared with the controls. No difference in the incidence of AEs was observed between the two groups. Similarly, no significant differences were found in the 6-MWD, D-dimer levels, or interleukin-6 concentrations between the MSC and control groups. CONCLUSIONS: Our results demonstrate the safety and potential of MSC treatment for improved lung lesions and pulmonary function in convalescent COVID-19 patients. However, comprehensive and long-term studies are required to confirm the efficacy of MSC treatment. TRIAL REGISTRATION Chinese Clinical Trial Registry, ChiCTR2000031430.
Humans ; COVID-19/therapy* ; Female ; Male ; Mesenchymal Stem Cell Transplantation/adverse effects* ; Middle Aged ; Adult ; Umbilical Cord/cytology* ; Mesenchymal Stem Cells/cytology* ; SARS-CoV-2 ; Aged ; Treatment Outcome

BACKGROUND: The protective effect of mesenchymal stem cells (MSCs) on cardiac ischemia-reperfusion (I/R) injury has been widely reported. Dental pulp-derived mesenchymal stem cells (DP-MSCs) have therapeutic effects on various diseases, including diabetes and cirrhosis. This study aimed to determine the therapeutic effects of DP-MSCs on I/R injury and elucidate the underlying mechanism. METHODS: Myocardial I/R injury model mice were treated with DP-MSCs or a miR-19a-3p mimic. The infarct volume, fibrotic area, pyroptosis, inflammation level, and cardiac function were measured. Cardiomyocytes exposed to hypoxia-reoxygenation were transfected with the miR-19a-3p mimic, miR-19a-3p inhibitor, or negative control. Pyroptosis and protein expression in the interferon regulatory factor 8/mitogen-activated protein kinase (IRF-8/MAPK) pathway were measured. RESULTS: DP-MSCs protected cardiac function in cardiac I/R-injured mice and inhibited cardiomyocyte pyroptosis. The upregulation of miR-19a-3p protected cardiac function, inhibited cardiomyocyte pyroptosis, and inhibited IRF-8/MAPK signaling in cardiac I/R-injured mice. DP-MSCs inhibited cardiomyocyte pyroptosis and the IRF-8/MAPK signaling by upregulating the miR-19a-3p levels in cardiomyocytes injured by I/R. CONCLUSION DP-MSCs protected cardiac function by inhibiting cardiomyocyte pyroptosis through miR-19a-3p under I/R conditions.
Animals ; MicroRNAs/metabolism* ; Pyroptosis/genetics* ; Mesenchymal Stem Cells/metabolism* ; Myocytes, Cardiac/cytology* ; Mice ; Male ; Mice, Inbred C57BL ; Dental Pulp/cytology* ; Myocardial Reperfusion Injury/therapy* ; MAP Kinase Signaling System/physiology*

Steroid-induced osteonecrosis of femoral head (SONFH) is a disease characterized by femoral head collapse and local pain caused by excessive use of glucocorticoids. Peroxisome proliferator-activated receptor-γ (PPARγ) is mainly expressed in adipose tissue. Wnt/β-catenin, AMPK and other related signaling pathways play an important role in regulating adipocyte differentiation, fatty acid uptake and storage. Bone marrow mesenchymal cells (BMSCs) have the ability to differentiate into adipocytes or osteoblasts, and the use of hormones upregulates PPARγ expression, resulting in BMSCs biased towards adipogenic differentiation. The increase of adipocytes affects the blood supply and metabolism of the femoral head, and the decrease of osteoblasts leads to the loss of trabecular bone, which eventually leads to partial or total ischemic necrosis and collapse of the femoral head. MicroRNAs (miRNAs) are a class of short non-coding RNAs that regulate gene expression by inhibiting the transcription or translation of target genes, thereby affecting cell function and disease progression. Studies have shown that miRNAs affect the progression of SONFH by regulating PPARγ lipid metabolism-related signaling pathways. Therefore, it may be an accurate and feasible SONFH treatment strategy to regulate adipogenic-osteoblast differentiation in BMSCs by targeted intervention of miRNA differential expression to improve lipid metabolism. In this paper, the miRNA-mediated PPARγ-related signaling pathways were classified and summarized to clarify their effects on lipid metabolism in SONFH, providing a theoretical reference for miRNA targeted therapy of SONFH, and then providing scientific evidence for SONFH precision medicine.
MicroRNAs/physiology* ; PPAR gamma/metabolism* ; Femur Head Necrosis/metabolism* ; Humans ; Signal Transduction/physiology* ; Lipid Metabolism/physiology* ; Animals ; Cell Differentiation ; Mesenchymal Stem Cells/cytology* ; Glucocorticoids/adverse effects*

OBJECTIVES: To explore the mechanism by which Tougu Xiaotong Capsule (TXC) promotes chondrogenic differentiation and cartilage repair in mice with osteoarthritis (OA). METHODS: Fifty 8-week-old male C57BL mice were randomly divided into normal control group, cartilage damage (induced by subchondral ring-shaped drilling) model group and TXC treatment groups at low, moderate and high doses (184, 368 and 736 mg/kg, respectively). Saline (in normal control and model groups) and TXC were administered after modeling by daily gavage for 6 consecutive weeks. The changes of cartilage damage in the mice were assessed by measuring thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) and using micro-CT, modified safranine O and fast green staining, HE staining, and qPCR. Primary cultures of mouse synovial mesenchymal stem cells (SMSCs) with lentivirus vector transfection for interfering CXCL12, TXC treatment, or both for 24 h were examined for chondrogenic differentiation using immunofluorescence staining, scratch assay, immunocytochemistry, and Western blotting. RESULTS: In mouse models with cartilage damage, TXC treatment at the moderate dose significantly alleviated joint pain, promoted cartilage repair, and upregulated the mRNA expression levels of CXCL12, GDF5, collagen II, aggrecan, Comp and Sox9 in the cartilage tissue. In primary mouse SMSCs, CXCL12 knockdown resulted in significant reduction of GDF5 protein expression, migration ability and Sox9 protein expression, and these changes were obviously reversed by TXC treatment. CONCLUSIONS TXC promotes chondrogenic differentiation of mouse SMSCs to promote repair of cartilage damage in mice by activating the CXCL12/GDF5 pathway.
Animals ; Drugs, Chinese Herbal/therapeutic use* ; Osteoarthritis/metabolism* ; Male ; Growth Differentiation Factor 5/metabolism* ; Mice, Inbred C57BL ; Mice ; Chemokine CXCL12/metabolism* ; Signal Transduction/drug effects* ; Cell Differentiation/drug effects* ; Cartilage, Articular/drug effects* ; Mesenchymal Stem Cells/cytology*

OBJECTIVES: To investigate the mechanism by which chitosan (CS) hydrogel loaded with human umbilical cord mesenchymal stem cell (HUVECs)-derived exosomes (hUCMSC-exos) (Exos@CS-Gel) improves diabetic wound healing. METHODS: hUCMSC-exos were extracted and Exos@CS-Gel was prepared. The effect of Exos@CS-Gel on proliferation and migration of HUVECs were evaluated using scratch wound assay and CCK-8 assay. Diabetic rat models with full-thickness skin wounds established by streptozotocin induction were randomized divided into 4 groups for treatment with Exos@CS-Gel (100 µg hUCMSC-exos dissolved in 100 µL 24% CS hydrogel), hUCMSC-exos (100 µg hUCMSC-exos dissolved in 100 µL PBS), CS hydrogel (100 µL 24% CS hydrogel), or PBS (control group). Wound healing and the therapeutic mechanisms were assessed using immunohistochemistry, HE staining, immunofluorescence, and qRT-PCR. RESULTS: In cultured HUVECs, Exos@CS-Gel treatment significantly promoted cell proliferation and migration. In the rat models of chronic diabetic wounds, the wound healing rate in Exos@CS-Gel group reached 92.7% on day 14, significantly higher than those in hUCMSC-exos group (9.12%), CS hydrogel group (16.28%), and control group (25.98%). Microvessel density and the expression levels of vascular endothelial growth factor and transforming growth factor β-1 were significantly increased in the Exos@CS-Gel group. CONCLUSIONS Exos@CS-Gel promotes survival capacity of hUCMSC-exos in vitro and accelerates diabetic wound healing in rats by promoting angiogenesis and cell proliferation.
Animals ; Wound Healing ; Humans ; Chitosan ; Exosomes ; Mesenchymal Stem Cells/cytology* ; Diabetes Mellitus, Experimental ; Rats ; Umbilical Cord/cytology* ; Hydrogels ; Human Umbilical Vein Endothelial Cells ; Cell Proliferation ; Rats, Sprague-Dawley ; Male

The ambiguity of etiology makes temporomandibular joint osteoarthritis (TMJOA) "difficult-to-treat". Emerging evidence underscores the therapeutic promise of exosomes in osteoarthritis management. Nonetheless, challenges such as low yields and insignificant efficacy of current exosome therapies necessitate significant advances. Addressing lower strontium (Sr) levels in arthritic synovial microenvironment, we studied the effect of Sr element on exosomes and miRNA selectively loading in synovial mesenchymal stem cells (SMSCs). Here, we developed an optimized system that boosts the yield of SMSC-derived exosomes (SMSC-EXOs) and improves their miRNA profiles with an elevated proportion of beneficial miRNAs, while reducing harmful ones by pretreating SMSCs with Sr. Compared to untreated SMSC-EXOs, Sr-pretreated SMSC-derived exosomes (Sr-SMSC-EXOs) demonstrated superior therapeutic efficacy by mitigating chondrocyte ferroptosis and reducing osteoclast-mediated joint pain in TMJOA. Our results illustrate Alix's crucial role in Sr-triggered miRNA loading, identifying miR-143-3p as a key anti-TMJOA exosomal component. Interestingly, this system is specifically oriented towards synovium-derived stem cells. The insight into trace element-driven, site-specific miRNA selectively loading in SMSC-EXOs proposes a promising therapeutic enhancement strategy for TMJOA.
MicroRNAs/metabolism* ; Mesenchymal Stem Cells/drug effects* ; Osteoarthritis/drug therapy* ; Exosomes/drug effects* ; Strontium/pharmacology* ; Synovial Membrane/cytology* ; Humans ; Animals ; Temporomandibular Joint Disorders/therapy* ; Temporomandibular Joint

Dental mesenchymal stem cells (DMSCs) are pivotal for tooth development and periodontal tissue health and play an important role in tissue engineering and regenerative medicine because of their multidirectional differentiation potential and self-renewal ability. The cellular microenvironment regulates the fate of stem cells and can be modified using various optimization techniques. These methods can influence the cellular microenvironment, activate disparate signaling pathways, and induce different biological effects. "Epigenetic regulation" refers to the process of influencing gene expression and regulating cell fate without altering DNA sequences, such as histone methylation. Histone methylation modifications regulate pivotal transcription factors governing DMSCs differentiation into osteo-/odontogenic lineages. The most important sites of histone methylation in tooth organization were found to be H3K4, H3K9, and H3K27. Histone methylation affects gene expression and regulates stem cell differentiation by maintaining a delicate balance between major trimethylation sites, generating distinct chromatin structures associated with specific downstream transcriptional states. Several crucial signaling pathways associated with osteogenic differentiation are susceptible to modulation via histone methylation modifications. A deeper understanding of the regulatory mechanisms governing histone methylation modifications in osteo-/odontogenic differentiation and immune-inflammatory responses of DMSCs will facilitate further investigation of the epigenetic regulation of histone methylation in DMSC-mediated tissue regeneration and inflammation. Here is a concise overview of the pivotal functions of epigenetic histone methylation at H3K4, H3K9, and H3K27 in the regulation of osteo-/odontogenic differentiation and renewal of DMSCs in both non-inflammatory and inflammatory microenvironments. This review summarizes the current research on these processes in the context of tissue regeneration and therapeutic interventions.
Mesenchymal Stem Cells/physiology* ; Humans ; Osteogenesis/genetics* ; Histones/metabolism* ; Cell Differentiation/physiology* ; Methylation ; Odontogenesis/genetics* ; Epigenesis, Genetic

Mesenchymal stem cells are highly regarded for their potential in tissue repair and regenerative medicine due to their multipotency and self-renewal abilities. Recently, mesenchymal stem cells have been redefined as "medical signaling cells," with their primary biological effects mediated through exosome secretion. These exosomes, which contain lipids, proteins, RNA, and metabolites, are crucial in regulating various biological processes and enhancing regenerative therapies. Exosomes replicate the effects of their parent cells while offering benefits such as reduced side effects, low immunogenicity, excellent biocompatibility, and high drug-loading capacity. Dental stem cells, including those from apical papilla, gingiva, dental pulp, and other sources, are key contributors to exosome-mediated regenerative effects, such as tumor cell apoptosis, neuroprotection, angiogenesis, osteogenesis, and immune modulation. Despite their promise, clinical application of exosomes is limited by challenges in isolation techniques. Current methods face issues of complexity, inefficiency, and insufficient purity, hindering detailed analysis. Recent advancements, such as micro-electromechanical systems, alternating current electroosmosis, and serum-free three-dimensional cell cultures, have improved exosome isolation efficacy. This review synthesizes nearly 200 studies on dental stem cell-derived exosomes, highlighting their potential in treating a wide range of conditions, including periodontal diseases, cancer, neurodegenerative disorders, diabetes, and more. Optimized isolation methods offer a path forward for overcoming current limitations and advancing the clinical use of exosome-based therapies.
Exosomes/physiology* ; Humans ; Mesenchymal Stem Cells/cytology* ; Dental Pulp/cytology* ; Stem Cells/cytology* ; Tooth/cytology*

Periodontal bone defects, primarily caused by periodontitis, are highly prevalent in clinical settings and manifest as bone fenestration, dehiscence, or attachment loss, presenting a significant challenge to oral health. In regenerative medicine, harnessing developmental principles for tissue repair offers promising therapeutic potential. Of particular interest is the condensation of progenitor cells, an essential event in organogenesis that has inspired clinically effective cell aggregation approaches in dental regeneration. However, the precise cellular coordination mechanisms during condensation and regeneration remain elusive. Here, taking the tooth as a model organ, we employed single-cell RNA sequencing to dissect the cellular composition and heterogeneity of human dental follicle and dental papilla, revealing a distinct Platelet-derived growth factor receptor alpha (PDGFRA) mesenchymal stem/stromal cell (MSC) population with remarkable odontogenic potential. Interestingly, a reciprocal paracrine interaction between PDGFRA⁺ dental follicle stem cells (DFSCs) and CD31⁺ Endomucin⁺ endothelial cells (ECs) was mediated by Vascular endothelial growth factor A (VEGFA) and Platelet-derived growth factor subunit BB (PDGFBB). This crosstalk not only maintains the functionality of PDGFRA⁺ DFSCs but also drives specialized angiogenesis. In vivo periodontal bone regeneration experiments further reveal that communication between PDGFRA⁺ DFSC aggregates and recipient ECs is essential for effective angiogenic-osteogenic coupling and rapid tissue repair. Collectively, our results unravel the importance of MSC-EC crosstalk mediated by the VEGFA and PDGFBB-PDGFRA reciprocal signaling in orchestrating angiogenesis and osteogenesis. These findings not only establish a framework for deciphering and promoting periodontal bone regeneration in potential clinical applications but also offer insights for future therapeutic strategies in dental or broader regenerative medicine.
Receptor, Platelet-Derived Growth Factor alpha/metabolism* ; Humans ; Neovascularization, Physiologic/physiology* ; Dental Sac/cytology* ; Single-Cell Analysis ; Transcriptome ; Mesenchymal Stem Cells/metabolism* ; Bone Regeneration ; Animals ; Dental Papilla/cytology* ; Periodontium/physiology* ; Stem Cells/metabolism* ; Regeneration ; Angiogenesis

Positional information plays a crucial role in embryonic pattern formation, yet its role in tooth development remains unexplored. In this study, we investigated the regional specification of lingual and buccal dental mesenchyme during tooth development. Tooth germs at the cap stage were dissected from mouse mandibles, and their lingual and buccal mesenchymal regions were separated for bulk RNA sequencing. Gene ontology analysis revealed that odontogenesis, pattern specification, and proliferation-related genes were enriched in the lingual mesenchyme, whereas stem cell development, mesenchymal differentiation, neural crest differentiation, and regeneration-related genes were predominant in the buccal mesenchyme. Reaggregation experiments using Wnt1^creERT/+; R26R^tdT/+ and WT mouse models demonstrated that lingual mesenchyme contributes to tooth formation, while buccal mesenchyme primarily supports surrounding tissues. Furthermore, only the lingual part of tooth germs exhibited odontogenic potential when cultured in vitro and transplanted under the kidney capsule. Bulk RNA transcriptomic analysis further validated the regional specification of the lingual and buccal mesenchyme. These findings provide novel insights into the molecular basis of positional information in tooth development and pattern formation.
Animals ; Mice ; Odontogenesis/genetics* ; Tooth Germ/cytology* ; Mesoderm/cytology* ; Cell Differentiation ; Mesenchymal Stem Cells ; Tooth/embryology*