OBJECTIVE: To Investigate the effects of lithocholic acid (LCA) on the balance between osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). METHODS: Twelve 10-week-old SPF C57BL/6J female mice were randomly divided into an experimental group (undergoing bilateral ovariectomy) and a control group (only removing the same volume of adipose tissue around the ovaries), with 6 mice in each group. The body mass was measured every week after operation. After 4 weeks post-surgery, the weight of mouse uterus was measured, femur specimens of the mice were taken for micro-CT scanning and three-dimensional reconstruction to analyze changes in bone mass. Tibia specimens were taken for HE staining to calculate the number and area of bone marrow adipocytes in the marrow cavity area. ELISA was used to detect the expression of bone turnover markers in the serum. Liver samples were subjected to real-time fluorescence quantitative PCR (RT-qPCR) to detect the expression of key genes related to bile acid metabolism, including cyp7a1, cyp7b1, cyp8b1, and cyp27a1. BMSCs were isolated by centrifugation from 2 C57BL/6J female mice (10-week-old). The third-generation cells were exposed to 0, 1, 10, and 100 μmol/L LCA, following which cell viability was evaluated using the cell counting kit 8 assay. Subsequently, alkaline phosphatase (ALP) staining and oil red O staining were conducted after 7 days of osteogenic and adipogenic induction. RT-qPCR was employed to analyze the expressions of osteogenic-related genes, namely ALP, Runt-related transcription factor 2 (Runx2), and osteocalcin (OCN), as well as adipogenic-related genes including Adiponectin (Adipoq), fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor γ (PPARγ). RESULTS: Compared with the control group, the body mass of the mice in the experimental group increased, the uterus atrophied, the bone mass decreased, the bone marrow fat expanded, and the bone metabolism showed a high bone turnover state. RT-qPCR showed that the expressions of cyp7a1, cyp8b1, and cyp27a1, which were related to the key enzymes of bile acid metabolism in the liver, decreased significantly ( P<0.05), while the expression of cyp7b1 had no significant difference ( P>0.05). Intervention with LCA at concentrations of 1, 10, and 100 μmol/L did not demonstrate any apparent toxic effects on BMSCs. Furthermore, LCA inhibited the expressions of osteogenic-related genes (ALP, Runx2, and OCN) in a dose-dependent manner, resulting in a reduction in ALP staining positive area. Concurrently, LCA promoted the expressions of adipogenic-related genes (Adipoq, FABP4, and PPARγ), and an increase in oil red O staining positive area. CONCLUSION After menopause, the metabolism of bile acids is altered, and secondary bile acid LCA interferes with the balance of osteogenic and adipogenic differentiation of BMSCs, thereby affecting bone remodelling.
Female ; Mice ; Animals ; Core Binding Factor Alpha 1 Subunit/pharmacology* ; PPAR gamma/metabolism* ; Steroid 12-alpha-Hydroxylase/metabolism* ; Mice, Inbred C57BL ; Cell Differentiation ; Osteogenesis ; Mesenchymal Stem Cells ; Bile Acids and Salts/pharmacology* ; Bone Marrow Cells ; Cells, Cultured ; Azo Compounds

Objective: To observe the effects of exosomes derived from human umbilical cord mesenchymal stem cells on the proliferation and invasion of pancreatic cancer cells, and to analyze the contents of exosomes and explore the mechanisms affecting pancreatic cancer cells. Methods: Exosomes extracted from human umbilical cord mesenchymal stem cells were added to pancreatic cancer cells BxPC3, Panc-1 and mouse models of pancreatic cancer, respectively. The proliferative activity and invasion abilities of BxPC3 and Panc-1 cells were measured by cell counting kit-8 (CCK-8) and Transwell assays. The expressions of miRNAs in exosomes were detected by high-throughput sequencing. GO and KEGG were used to analyze the related functions and the main metabolic pathways of target genes with high expressions of miRNAs. Results: The results of CCK-8 cell proliferation assay showed that the absorbance of BxPC3 and Panc-1 cells in the hucMSCs-exo group was significantly higher than that in the control group [(4.68±0.09) vs. (3.68±0.01), P<0.05; (5.20±0.20) vs. (3.45±0.17), P<0.05]. Transwell test results showed that the number of invasion cells of BxPC3 and Panc-1 in hucMSCs-exo group was significantly higher than that in the control group (129.40±6.02) vs. (89.40±4.39), P<0.05; (134.40±7.02) vs. (97.00±6.08), P<0.05. In vivo experimental results showed that the tumor volume and weight in the exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs-exo) group were significantly greater than that in the control group [(884.57±59.70) mm(3) vs. (695.09±57.81) mm(3), P<0.05; (0.94±0.21) g vs. (0.60±0.13) g, P<0.05]. High-throughput sequencing results showed that miR-148a-3p, miR-100-5p, miR-143-3p, miR-21-5p and miR-92a-3p were highly expressed. GO and KEGG analysis showed that the target genes of these miRNAs were mainly involved in the regulation of glucosaldehylation, and the main metabolic pathways were ascorbic acid and aldehyde acid metabolism, which were closely related to the development of pancreatic cancer. Conclusion: Exosomes derived from human umbilical cord mesenchymal stem cells can promote the growth of pancreatic cancer cells and the mechanism is related to miRNAs that are highly expressed in exosomes.
Mice ; Animals ; Humans ; MicroRNAs/metabolism* ; Exosomes/genetics* ; Sincalide/metabolism* ; Pancreatic Neoplasms/metabolism* ; Carcinoma, Pancreatic Ductal/genetics* ; Mesenchymal Stem Cells/metabolism* ; Umbilical Cord

BACKGROUND: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown. METHODS: Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca 2+ -related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance. RESULTS: Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca 2+ is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments. CONCLUSIONS Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.
Animals ; Humans ; Mice ; Apoptosis ; Bone Marrow Cells ; Cell Communication ; Connexin 43/genetics* ; Gap Junctions/metabolism* ; Imatinib Mesylate/therapeutic use* ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology* ; Mesenchymal Stem Cells/metabolism* ; Tumor Microenvironment ; Calcium/metabolism*

Objective To explore the effect of microRNA-22-3p (miR-22-3p) regulating the expression of Kruppel-like factor 6 (KLF6) on the cardiomyocyte-like differentiation of bone marrow mesenchymal stem cell (BMSC). Methods Rat BMSC was isolated and cultured,and the third-generation BMSC was divided into a control group,a 5-azacytidine(5-AZA)group,a mimics-NC group,a miR-22-3p mimics group,a miR-22-3p mimics+pcDNA group,and a miR-22-3p mimics+pcDNA-KLF6 group.Real-time fluorescent quantitative PCR (qRT-PCR) was carried out to determine the expression of miR-22-3p and KLF6 in cells.Immunofluorescence staining was employed to detect the expression of Desmin,cardiac troponin T (cTnT),and connexin 43 (Cx43).Western blotting was employed to determine the protein levels of cTnT,Cx43,Desmin,and KLF6,and flow cytometry to detect the apoptosis of BMSC.The targeting relationship between miR-22-3p and KLF6 was analyzed by dual luciferase reporter gene assay. Results Compared with the control group,5-AZA up-regulated the expression of miR-22-3p (q=7.971,P<0.001),Desmin (q=7.876,P<0.001),cTnT (q=10.272,P<0.001),and Cx43 (q=6.256,P<0.001),increased the apoptosis rate of BMSC (q=12.708,P<0.001),and down-regulated the mRNA (q=20.850,P<0.001) and protein (q=11.080,P<0.001) levels of KLF6.Compared with the 5-AZA group and the mimics-NC group,miR-22-3p mimics up-regulated the expression of miR-22-3p (q=3.591,P<0.001;q=11.650,P<0.001),Desmin (q=5.975,P<0.001;q=13.579,P<0.001),cTnT (q=7.133,P<0.001;q=17.548,P<0.001),and Cx43 (q=4.571,P=0.037;q=11.068,P<0.001),and down-regulated the mRNA (q=7.384,P<0.001;q=28.234,P<0.001) and protein (q=4.594,P=0.036;q=15.945,P<0.001) levels of KLF6.The apoptosis rate of miR-22-3p mimics group was lower than that of 5-AZA group (q=8.216,P<0.001).Compared with the miR-22-3p mimics+pcDNA group,miR-22-3p mimics+pcDNA-KLF6 up-regulated the mRNA(q=23.891,P<0.001) and protein(q=13.378,P<0.001)levels of KLF6,down-regulated the expression of Desmin (q=9.505,P<0.001),cTnT (q=10.985,P<0.001),and Cx43 (q=8.301,P<0.001),and increased the apoptosis rate (q=4.713,P=0.029).The dual luciferase reporter gene experiment demonstrated that KLF6 was a potential target gene of miR-22-3p. Conclusion MiR-22-3p promotes cardiomyocyte-like differentiation of BMSC by inhibiting the expression of KLF6.
Animals ; Rats ; Myocytes, Cardiac ; Kruppel-Like Factor 6 ; Connexin 43 ; Desmin ; Cell Differentiation ; Azacitidine/pharmacology* ; Mesenchymal Stem Cells ; RNA, Messenger ; MicroRNAs

The study aims to explore the effect of mesenchymal stem cells-derived exosomes (MSCs-Exo) on staurosporine (STS)-induced chondrocyte apoptosis before and after exposure to pulsed electromagnetic field (PEMF) at different frequencies. The AMSCs were extracted from the epididymal fat of healthy rats before and after exposure to the PEMF at 1 mT amplitude and a frequency of 15, 45, and 75 Hz, respectively, in an incubator. MSCs-Exo was extracted and identified. Exosomes were labeled with DiO fluorescent dye, and then co-cultured with STS-induced chondrocytes for 24 h. Cellular uptake of MSC-Exo, apoptosis, and the protein and mRNA expression of aggrecan, caspase-3 and collagenⅡA in chondrocytes were observed. The study demonstrated that the exposure of 75 Hz PEMF was superior to 15 and 45 Hz PEMF in enhancing the effect of exosomes in alleviating chondrocyte apoptosis and promoting cell matrix synthesis. This study lays a foundation for the regulatory mechanism of PEMF stimulation on MSCs-Exo in inhibiting chondrocyte apoptosis, and opens up a new direction for the prevention and treatment of osteoarthritis.
Animals ; Rats ; Apoptosis ; Chondrocytes ; Electromagnetic Fields ; Exosomes/physiology* ; Mesenchymal Stem Cells/metabolism*

OBJECTIVE: To investigate the expression of pyruvate kinase M2 (PKM2) in bone marrow mesenchymal stem cells (BMSCs) in myeloma bone disease (MBD) and its effect on osteogenic and adipogenic differentiation of BMSCs. METHODS: BMSCs were isolated from bone marrow of five patients with multiple myeloma (MM) (MM group) and five with iron deficiency anemia (control group) for culture and identification. The expression of PKM2 protein were compared between the two groups. The differences between osteogenic and adipogenic differentiation of BMSCs were assessed by using alkaline phosphatase (ALP) and oil red O staining, and detecting marker genes of osteogenesis and adipogenesis. The effect of MM cell line (RPMI-8226) and BMSCs co-culture on the expression of PKM2 was explored. Functional analysis was performed to investigate the correlations of PKM2 expression of MM-derived BMSCs with osteogenic and adipogenic differentiation by employing PKM2 activator and inhibitor. The role of orlistat was explored in regulating PKM2 expression, osteogenic and adipogenic differentiation of MM-derived BMSCs. RESULTS: Compared with control, MM-originated BMSCs possessed the ability of increased adipogenic and decreased osteogenic differentiation, and higher level of PKM2 protein. Co-culture of MM cells with BMSCs markedly up-regulated the expression of PKM2 of BMSCs. Up-regulation of PKM2 expression could promote adipogenic differentiation and inhibit osteogenic differentiation of MM-derived BMSCs, while down-regulation of PKM2 showed opposite effect. Orlistat significantly promoted osteogenic differentiation in MM-derived BMSCs via inhibiting the expression of PKM2. CONCLUSION The overexpression of PKM2 can induce the inhibition of osteogenic differentiation of BMSCs in MBD. Orlistat can promote the osteogenic differentiation of BMSCs via inhibiting the expression of PKM2, indicating a potential novel agent of anti-MBD therapy.
Humans ; Adipogenesis ; Bone Diseases/metabolism* ; Bone Marrow Cells ; Cell Differentiation ; Cells, Cultured ; Mesenchymal Stem Cells/physiology* ; Multiple Myeloma/metabolism* ; Orlistat/pharmacology* ; Osteogenesis/genetics*

OBJECTIVE: To explore the effect of hypoxia-supported umbilical cord mesenchymal stem cell (UC-MSC) on the expansion of cord blood mononuclear cell （MNC） in vitro. METHODS: The isolated cord blood mononuclear cells were inoculated on the preestablished umbilical cord mesenchymal stem cell layer and cultured under hypoxic conditions (3％ O₂) and the experimental groups were normoxia (MNCs were cultured under normoxic conditions), hypoxia (MNCs were cultured under hypoxic conditions), UC-MSC (MNCs were cultured with UC-MSC under normoxic conditions), and UC-MSC+hypoxia (MNCs were cultured with UC-MSC under hypoxic conditions). To further investigate the combinational effect of 3 factors of SCF+FL+TPO (SFT) on expansion of cord blood MNCs in vitro in hypoxia-supported UC-MSC culture system, the experiments were further divided into group A (MNCs were cultured with UC-MSC and SFT under normoxic conditions), group B (MNCs were cultured with UC-MSC under hypoxic conditions), group C (MNCs were cultured with UC-MSC and SFT under hypoxic conditions). The number of nucleated cells (TNC), CD34⁺ cell, CFU and CD34⁺CXCR4⁺, CD34⁺CD49d⁺, CD34⁺CD62L⁺ cells of each groups were detected at 0, 7, 10 and 14 days, respectively. RESULTS: Compared with group hypoxia and UC-MSC, group UC-MSC+hypoxia effectively promoted the expansion of TNC, CD34⁺ cell and CFU, and upregulated the expression level of adhesion molecule and CxCR4 of the cord blood CD34⁺ cell（P<0.05）. After culturing for 14 days, compared with group A and group B, group C effectively promoted the expansion of cord blood MNC at different time points（P<0.05）, and the effect of group A was better than that of group B at 7 and 10 days（P<0.05）. CONCLUSION Hypoxia-supported UC-MSC efficiently promoted the expansion and expression of adhesion molecule and CXCR4 of cord blood CD34⁺ cell, and the effect of expansion could be enhanced when SFT 3 factors were added.
Humans ; Cells, Cultured ; Fetal Blood ; Cell Proliferation ; Umbilical Cord/metabolism* ; Mesenchymal Stem Cells ; Antigens, CD34/metabolism* ; Hypoxia/metabolism*

Wound healing involves complex pathophysiological mechanism, among which angiogenesis is considered as one of the key steps in wound healing, and promoting wound angiogenesis can accelerate wound healing. In recent years, mesenchymal stem cell-derived extracellular vesicles have been proven to produce equivalent effects of wound healing promotion comparable to stem cell therapy, with the advantages of low antigenicity and high biocompatibility. The specific mechanism by which extracellular vesicles facilitate wound healing is still not fully understood and is thought to involve all stages of wound healing. This article focuses on the possible mechanism of extracellular vesicles of adipose-derived mesenchymal stem cells in promoting wound angiogenesis, so as to provide ideas for further study on the mechanism of extracellular vesicles to promote wound healing.
Wound Healing/physiology* ; Mesenchymal Stem Cells ; Extracellular Vesicles ; Stem Cell Transplantation

Since researchers have found that the conditioned medium and exosomes of mesenchymal stem cells (MSCs) had the biological effects equivalent to those of MSCs, MSC exosomes (MSC-Exos), the representative product of MSCs' paracrine effect, have become the research focus of the "cell-free" therapy of MSCs. However, most researchers currently use conventional culture condition to culture MSCs and then isolate exosomes for the treatment of wound or other diseases. Theoretically, the paracrine effect of MSCs is directly associated with the pathological condition of the wound (disease) microenvironment or in vitro culture condition, and their paracrine components and biological effects may be altered with the changes of the wound (disease) microenvironment or in vitro culture condition. Thus, the feasibility of using traditional culture condition to culture MSCs for exosome extraction for the treatment of different diseases without considering the actual situation of the disease to be treated needs further discussion. Therefore, the author suggests that the research of MSC-Exos should consider the microenvironment of the wound (disease) to be treated. as much as possible, otherwise the extracted MSC-Exos may not be "accurate" or may not really achieve the treatment effect of MSCs. In this article, we summarized some thoughts of the author and problems related to the researches about MSC-Exos and wound microenvironment, and hoped to discuss with researchers.
Exosomes ; Cell- and Tissue-Based Therapy ; Culture Media, Conditioned ; Mesenchymal Stem Cells

Ex vivo culture-amplified mesenchymal stem cells (MSCs) have been studied because of their capacity for healing tissue injury. MSC transplantation is a valid approach for promoting the repair of damaged tissues and replacement of lost cells or to safeguard surviving cells, but currently the efficiency of MSC transplantation is constrained by the extensive loss of MSCs during the short post-transplantation period. Hence, strategies to increase the efficacy of MSC treatment are urgently needed. Iron overload, reactive oxygen species deposition, and decreased antioxidant capacity suppress the proliferation and regeneration of MSCs, thereby hastening cell death. Notably, oxidative stress (OS) and deficient antioxidant defense induced by iron overload can result in ferroptosis. Ferroptosis may inhibit cell survival after MSC transplantation, thereby reducing clinical efficacy. In this review, we explore the role of ferroptosis in MSC performance. Given that little research has focused on ferroptosis in transplanted MSCs, further study is urgently needed to enhance the in vivo implantation, function, and duration of MSCs.
Humans ; Antioxidants/metabolism* ; Ferroptosis ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stem Cells ; Iron Overload/metabolism*