Differentiation Of Marrow Mesenchymal Stem Cells Research Articles

Role of epigenetic regulatory mechanisms in age-related bone homeostasis imbalance.

Alterations to the human organism that are brought about by aging are comprehensive and detrimental. Of these, an imbalance in bone homeostasis is a major outward manifestation of aging. In older adults, the decreased osteogenic activity of bone marrow mesenchymal stem cells and the inhibition of bone marrow mesenchymal stem cell differentiation lead to decreased bone mass, increased risk of fracture, and impaired bone injury healing. In the past decades, numerous studies have reported the epigenetic alterations that occur during aging, such as decreased core histones, altered DNA methylation patterns, and abnormalities in noncoding RNAs, which ultimately lead to genomic abnormalities and affect the expression of downstream signaling osteoporosis treatment and promoter of fracture healing in older adults. The current review summarizes the impact of epigenetic regulation mechanisms on age-related bone homeostasis imbalance.

FABRICATION OF A HIGH-THROUGHPUT 3D-PRINTED OSTEOGENIC CORAL-CONTAINING SCAFFOLD

In 2021 the bone grafting market was worth €2.72 billion globally. As allograft bone has a limited supply and risk of disease transmission, the demand for synthetic grafting substitutes (BGS) continues to grow while allograft bone grafts steadily decrease. Synthetic BGS are low in mechanical strength and bioactivity, inspiring the development of novel grafting materials, a traditionally laborious and expensive process. Here a novel BGS derived from sustainably grown coral was evaluated. Coral-derived scaffolds are a natural calcium carbonate bio-ceramic, which induces osteogenesis in bone marrow mesenchymal stem cells (MSCs), the cells responsible for maintaining bone homeostasis and orchestrating fracture repair. By 3D printing MSCs in coral-laden bioinks we utilise high throughput (HT) fabrication and evaluation of osteogenesis, overcoming the limitations of traditional screening methods.MSC and coral-laden GelXA (CELLINK) bioinks were 3D printed in square bottom 96 well plates using a CELLINK BIO X printer with pneumatic adapter Samples were non-destructively monitored during the culture period, evaluating both the sample and the culture media for metabolism (PrestoBlue), cytotoxicity (lactose dehydrogenase (LDH)) and osteogenic differentiation (alkaline phosphatase (ALP)). Endpoint, destructive assays used included qRT-PCR and SEM imaging.The inclusion of coral in the printed bioink was biocompatable with the MSCs, as reflected by maintained metabolism and low LDH release. The inclusion of coral induced osteogenic differentiation in the MSCs as seen by ALP secretion and increased RUNX2, collagen I and osteocalcin transcription.Sustainably grown coral was successfully incorporated into bioinks, reproducibly 3D printed, non-destructively monitored throughout culture and induced osteogenic differentiation in MSCs. This HT fabrication and monitoring workflow offers a faster, less labour-intensive system for the translation of bone substitute materials to clinic.Acknowledgements: This work was co-funded by Enterprise Ireland and Zoan Biomed through Innovation Partnership IP20221024.

Comparison of techniques for corneal epithelium cell culture for the collection of conditioned medium.

To determine the best protocol in obtaining the higher yield of conditioned culture medium to be used for the bone marrow mesenchymal stem cell differentiation into corneal epithelial cells, five techniques for the primary culture of human corneal epithelial cells were evaluated. The studied culture techniques of corneal epithelial cells were: explants in culture flasks with and without hydrophilic surface treatment, on amniotic membrane, with enzymatic digestion, and by corneal scraping. The conditioned culture medium collected from these cultures was used to differentiate human bone marrow mesenchymal stem cells into corneal epithelial cells, which were characterized using flow cytometry with pan-cytokeratin and the corneal-specific markers, cytokeratin 3 and cytokeratin 12. The culture technique using flasks with hydrophilic surface treatment resulted in the highest yield of conditioned culture medium. Flasks without surface treatment resulted to a very low success rate. Enzymatic digestion and corneal scraping showed contamination with corneal fibroblasts. The culture on amniotic membranes only allowed the collection of culture medium during the 1st cell confluence. The effectiveness of cell differentiation was confirmed by cytometry analysis using the collected conditioned culture medium, as demonstrated by the expressions of cytokeratin 3 (95.3%), cytokeratin 12 (93.4%), and pan-cytokeratin (95.3%). The culture of corneal epithelial cell explants in flasks with hydrophilic surface treatment is the best technique for collecting a higher yield of conditioned culture medium to be used to differentiate mesenchymal stem cells.

Bone Marrow Stromal Stem Cell Fate Decision: A Potential Mechanism For Bone Marrow Adipose Increase with Aging-related Osteoporosis.

Osteoporosis is a systemic bone disease that seriously threatens the health and quality of life in middle-aged and older adults. In this review, we describe the relationship between bone marrow adipose tissue and aging osteoporosis and mainly focus on bone marrow mesenchymal stem cell osteogenic-adipose differentiation fate with aging along with the relevant mechanisms responsible for these changes. We summarized recent advances in regulating the bone marrow mesenchymal stem cell differentiation due to aging in this review. Aging-related bone mass loss is accompanied by expanding bone marrow adipose because of an imbalance of bone marrow mesenchymal stem cell differentiation, resulting in adipogenesis. Ectopic adipocytes in the bone marrow increase with age and are a key factor responsible for the aging-related bone mass decrease. Transcription factors and classical regulating pathways are involved in this process during aging. As the global aging population increases, not only older women but also older men face a great fracture risk. Therefore, finding molecular mechanisms controlling the stimulating adipogenesis in BMSC during aging is important for providing the new cue for prevention and therapeutics for aging-related bone loss. Furthermore, upon physical examination of older people, except for the bone mineral density and bone turnover biochemical marker, the bone marrow adipose measurement should be taken into account when assessing the fracture risk and treatment plan that will be beneficial in clinical practice.

Parvovirus B19 Infection May Potentially Determine the Fate of Hematopoiesis by Altering the Human Bone Marrow Mesenchymal Stem Cells Differentiation

Background: Human bone marrow mesenchymal stem cells (hBM-MSCs), as supporters for hematopoiesis, differentiate into osteoblasts and adipocytes. Studies showed that infection of hBM-MSCs by Parvovirus B19 (B19V) can affect the differentiation capability of hBM-MSCs. This study aims to evaluate B19V effects on the differentiation of hBM-MSCs.
 Materials and Methods: In this experimental study hBM-MSCs were cultured up to passage 3. Nucleofection was subsequently employed to deliver a plasmid containing the B19V genome into the cells. The transfected cells were then differentiated into osteoblast and adipocyte lineages. qRT-PCR was then performed to analyze the differentiation 14 days after transfection.
 Results: On the 14th day after induction the findings demonstrated a significant increase in adipocyte-specific (PPARγ and LPL) gene expression compared to the control group (p<0.05) and a slight but not statistically significant decrease in the expression of the osteocyte-specific genes (RUNX2 and osteocalcin) (p>0.05).
 Conclusion: The results suggest that B19V infection can promote the differentiation of hBM-MSCs towards adipocytes and affect the bone marrow microenvironment as well as hematopoiesis

Retracted: Depth Vision-Based Assessment of Bone Marrow Mesenchymal Stem Cell Differentiation Capacity in Patients with Congenital Scoliosis.

[This retracts the article DOI: 10.1155/2022/4890008.].

Flexible Fabrication and Hybridization of Bioactive Hydrogels with Robust Osteogenic Potency.

Osteogenic scaffolds reproducing the natural bone composition, structures, and properties have represented the possible frontier of artificially orthopedic implants with the great potential to revolutionize surgical strategies against the bone-related diseases. However, it is difficult to achieve an all-in-one formula with the simultaneous requirement of favorable biocompatibility, flexible adhesion, high mechanical strength, and osteogenic effects. Here in this work, an osteogenic hydrogel scaffold fabricated by inorganic-in-organic integration between amine-modified bioactive glass (ABG) nanoparticles and poly(ethylene glycol) succinimidyl glutarate-polyethyleneimine (TSG-PEI) network was introduced as an all-in-one tool to flexibly adhere onto the defective tissue and subsequently accelerate the bone formation. Since the N-hydroxysuccinimide (NHS)-ester of tetra-PEG-SG polymer could quickly react with the NH2-abundant polyethyleneimine (PEI) polymer and ABG moieties, the TSG-PEI@ABG hydrogel was rapidly formed with tailorable structures and properties. Relying on the dense integration between the TSG-PEI network and ABG moieties on a nano-scale level, this hydrogel expressed powerful adhesion to tissue as well as durable stability for the engineered scaffolds. Therefore, its self-endowed biocompatibility, high adhesive strength, compressive modulus, and osteogenic potency enabled the prominent capacities on modulation of bone marrow mesenchymal stem cell (BMSCs) proliferation and differentiation, which may propose a potential strategy on the simultaneous scaffold fixation and bone regeneration promotion for the tissue engineering fields.

A test study of different nanofibre scaffolds in tracheal cartilage repair

Tracheal abnormalities occur in situations such as tracheal stenosis and bronchitis, causing serious adverse effects on the normal life of patients. Tracheal cartilage is one of the important tissues that maintain airway patency, but it is difficult to repair by itself. The electrospinning technology can be combined with growth factors, which has a certain positive effect on the repair of cartilage tissue. The study utilized coaxial electrospinning technology to prepare nanofiber scaffolds loaded with Kartogenin, and analyzed the effects of different nanofiber scaffolds on tracheal cartilage repair through experiments such as inducing bone marrow mesenchymal stem cell differentiation, in vitro release, and in vitro degradation. The results showed that within 87 seconds, the contact angle of the nanofiber scaffold corresponding to Kartogenin decreased from 121.94° to 50.14°. Kartogenin of 10±3 μM does not cause cytotoxicity to chondrocytes after 7 days of cultivation, and can maintain its phenotype well. As the transcription level of chondrocyte marker genes gradually increases, Kartogenin can induce bone marrow mesenchymal stem cells to differentiate into chondrocytes. The above results verify the good mechanical properties of Kartogenin after successfully loading into nanofibers, as well as its good cell compatibility, promoting chondrocyte differentiation, and providing a new method reference for tracheal cartilage repair.

Regulation of Osteoimmune Microenvironment and Osteogenesis by 3D-Printed PLAG/black Phosphorus Scaffolds for Bone Regeneration.

The treatment of bone defects remains a significant challenge to be solved clinically. Immunomodulatory properties of orthopedic biomaterials have significance in regulating osteoimmune microenvironment for osteogenesis. A lactic acid-co-glycolic acid (PLGA) scaffold incorporates black phosphorus (BP) fabricated by 3D printing technology to investigate the effect of BP on osteoimmunomodulation and osteogenesis in site. The PLGA/BP scaffold exhibits suitable biocompatibility, biodegradability, and mechanical properties as an excellent microenvironment to support new bone formation. The studies' result also demonstrate that the PLGA/BP scaffolds are able to recruit and stimulate macrophages M2polarization, inhibit inflammation, and promote human bone marrow mesenchymal stem cells (hBMSCs) proliferation and differentiation, which in turn promotes bone regeneration in the distal femoral defect region of steroid-associated osteonecrosis (SAON) rat model. Moreover, it is screened and demonstrated that PLGA/BP scaffolds can promote osteogenic differentiation by transcriptomic analysis, and PLGA/BP scaffolds promote osteogenic differentiation and mineralization by activating PI3K-AKTsignaling pathway in hBMSC cells. In this study, it is shown that the innovative PLGA/BP scaffolds are extremely effective in stimulating bone regeneration by regulating macrophage M2 polarization and a new strategy for the development of biomaterials that can be used to repair bone defects is offered.

Baicalin attenuates dexamethasone-induced apoptosis of bone marrow mesenchymal stem cells by activating the hedgehog signaling pathway.

Perturbations in bone marrow mesenchymal stem cell (BMSC) differentiation play an important role in steroid-induced osteonecrosis of the femoral head (SONFH). At present, studies on SONFH concentrate upon the balance within BMSC osteogenic and adipogenic differentiation. However, BMSC apoptosis as well as proliferation are important prerequisites in their differentiation. The hedgehog (HH) signaling pathway regulates bone cell apoptosis. Baicalin (BA), a well-known compound in traditional Chinese medicine, can affect the proliferation and apoptosis of numerous cell types via HH signaling. However, the potential role and mechanisms of BA on BMSCs are unclear. Thus, we aimed to explore the role of BA in dexamethasone (Dex)-induced BMSC apoptosis in this study. Primary BMSCs were treated with 10 -6 mol/L Dex alone or with 5.0 μmol/L, 10.0 μmol/L, or 50.0 μmol/L BA for 24 hours followed by co-treatment with 5.0 μmol/L, 10.0 μmol/L, or 50.0 μmol/L BA and 10 -6 mol/L Dex. Cell viability was assayed through the Cell Counting Kit-8 (CCK-8). Cell apoptosis was evaluated using Annexin V-fluorescein isothiocyanate/propidium iodide (PI) staining followed by flow cytometry. The imaging and counting, respectively, of Hochest 33342/PI-stained cells were used to assess the morphological characteristics and proportion of apoptotic cells. To quantify the apoptosis-related proteins (e.g., apoptosis regulator BAX [Bax], B-cell lymphoma 2 [Bcl-2], caspase-3, and cleaved caspase-3) and HH signaling pathway proteins, western blotting was used. A HH-signaling pathway inhibitor was used to demonstrate that BA exerts its anti-apoptotic effects via the HH signaling pathway. The results of CCK-8, Hoechst 33342/PI-staining, and flow cytometry showed that BA did not significantly promote cell proliferation (CCK-8: 0 μmol/L, 100%; 2.5 μmol/L, 98.58%; 5.0 μmol/L, 95.18%; 10.0 μmol/L, 98.11%; 50.0 μmol/L, 99.38%, F = 2.33, P > 0.05), but it did attenuate the effect of Dex on apoptosis (Hoechst 33342/PI-staining: Dex+ 50.0 μmol/L BA, 12.27% vs. Dex, 39.27%, t = 20.62; flow cytometry: Dex + 50.0 μmol/L BA, 12.68% vs. Dex, 37.43%, t = 11.56; Both P < 0.05). The results of western blotting analysis showed that BA reversed Dex-induced apoptosis by activating the HH signaling pathway, which down-regulated the expression of Bax, cleaved-caspase 3, and suppressor of fused (SUFU) while up-regulating Bcl-2, sonic hedgehog (SHH), and zinc finger protein GLI-1 (GLI-1) expression (Bax/Bcl-2: Dex+ 50.0 μmol/L BA, 1.09 vs. Dex, 2.76, t = 35.12; cleaved caspase-3/caspase-3: Dex + 50.0 μmol/L BA, 0.38 vs . Dex, 0.73, t = 10.62; SHH: Dex + 50.0 μmol/L BA, 0.50 vs . Dex, 0.12, t = 34.01; SUFU: Dex+ 50.0 μmol/L BA, 0.75 vs . Dex, 1.19, t = 10.78; GLI-1: Dex+ 50.0 μmol/L BA, 0.40 vs . Dex, 0.11, t = 30.68. All P < 0.05). BA antagonizes Dex-induced apoptosis of human BMSCs by activating the HH signaling pathway. It is a potential candidate for preventing SONFH.

Multi-omics analysis of bone marrow mesenchymal stem cell differentiation differences in osteoporosis

Osteoporosis is a systemic skeletal disease characterized by low bone mass and degradation of bone tissue microarchitecture, leading to enhanced bone fragility and increased fracture risk. However, the pathogenesis of osteoporosis is unclear. Our results showed that BMSCs dervied from ovariectomized rats had a higher capacity for osteogenesis and lipogenic differentiation compared to the control group. In the meantime, we identified a total of 205 differentially expressed proteins and 2294 differentially expressed genes in BMSCs isolated from ovariectomized rats by proteomics analysis and transcriptome sequencing, respectively. These differentially expressed proteins and genes were mainly involved in ECM-receptor interaction signaling pathway. We speculate that BMSCs derived from ovariectomized rats have a higher potential for bone formation because expression of ECM collagen or genes encoding collagen in the bone ECM in BMSCs isolated from ovariectomized rats are increased compared with that from control group, which provided the prerequisite for the increased bone turnover effect. To conclusion, our results may provid new ideas for further research on the pathogenesis of osteoporosis.

Effects of norepinephrine‑induced activation of rat vascular adventitial fibroblasts on proliferation and migration of BMSCs involved in vascular remodeling.

Vascular remodeling caused by vascular injury such as hypertension and atherosclerosis is a complex process involving a variety of cells and factors, and the mechanism is unclear. A vascular injury model was simulated by adding norepinephrine (NE) to culture medium of vascular adventitial fibroblasts (AFs). NE induced activation and proliferation of AFs. To investigate the association between the AFs activation and bone marrow mesenchymal stem cells (BMSCs) differentiation in vascular remodeling. BMSCs were cultured with supernatant of the AFs culture medium. BMSC differentiation and migration were observed by immunostaining and Transwell assay, respectively, while cell proliferation was measured using the Cell Counting Kit-8. Expression levels of smooth muscle actin (α-SMA), TGF-β1 and SMAD3 were measured using western blot assay. The results indicated that compared with those in the control group, in which BMSCs were cultured in normal medium, expression levels of α-SMA, TGF-β1 and SMAD3 in BMSCs cultured in medium supplemented with supernatant of AFs, increased significantly (all P<0.05). Activated AFs induced the differentiation of BMSCs into vascular smooth muscle-like cells and promoted proliferation and migration. AFs activated by NE may induce BMSCs to participate in vascular remodeling. These findings may help design and develop new approaches and therapeutic strategies for vascular injury to prevent pathological remodeling.

YBX1 Promotes MSC Osteogenic Differentiation by Activating the PI3K/AKT Pathway.

Bone metabolism has an essential role in bone disease, but its specific mechanism remains unclear. Y-Box Binding Protein 1 (YBX1) is a gene with broad nucleic acid binding properties, which encodes a highly conserved cold shock domain protein. Previous studies have shown that YBX1 is closely related to cell differentiation. However, the function of YBX1 in osteoblast differentiation of bone marrow mesenchymal stem cells (MSCs) was unclear. To explore the effect and specific mechanism of YBX1 in osteogenic differentiation of MSCs, we used PCR, Western blot, Alizarin red Staining, alkaline phosphatase (ALP) assays, and siRNA knockdown in our research. We found that YBX1 gradually increased during the process of osteogenic differentiation of MSCs. YBX1 siRNA could negatively regulate the MSCs osteogenic differentiation. Mechanistic studies revealed that YBX1 knockdown could inhibit PI3K/AKT pathway. Furthermore, the specific agonist (SC79) of PI3K/AKT pathway could restore the impaired MSCs osteogenic differentiation which was mediated by YBX1 knockdown. Taken together, we concluded that YBX1 could positively regulate the osteogenic differentiation of MSCs by activating the PI3K/AKT pathway. These results helped us further understand the mechanism of osteogenesis and revealed that YBX1 might be a selectable target in the bone repair field. Our study provides a new target and theoretical basis for the treatment of bone diseases.

Activating Wnt/β-catenin signaling by autophagic degradation of APC contributes to the osteoblast differentiation effect of soy isoflavone on osteoporotic mesenchymal stem cells.

The functional role of autophagy in regulating differentiation of bone marrow mesenchymal stem cells (MSCs) has been studied extensively, but the underlying mechanism remains largely unknown. The Wnt/β-catenin signaling pathway plays apivotal role in the initiation of osteoblast differentiation of mesenchymal progenitor cells, and the stability of core protein β-catenin is tightly controlled by the APC/Axin/GSK-3β/Ck1α complex. Here we showed that genistein, a predominant soy isoflavone, stimulated osteoblast differentiation of MSCs in vivo and in vitro. Female rats were subjected to bilateral ovariectomy (OVX); four weeks after surgery the rats were orally administered genistein (50 mg·kg-1·d-1) for 8 weeks. The results showed that genistein administration significantly suppressed the bone loss and bone-fat imbalance, and stimulated bone formation in OVX rats. In vitro, genistein (10 nM) markedly activated autophagy and Wnt/β-catenin signaling pathway, and stimulated osteoblast differentiation in OVX-MSCs. Furthermore, we found that genistein promoted autophagic degradation of adenomatous polyposis coli (APC), thus initiated β-catenin-driven osteoblast differentiation. Notably, genistein activated autophagy through transcription factor EB (TFEB) rather than mammalian target of rapamycin (mTOR). These findings unveil the mechanism of how autophagy regulates osteogenesis in OVX-MSCs, which expands our understanding that such interplay could be employed as a useful therapeutic strategy for treating postmenopausal osteoporosis.

MiR146a modulates chondrogenesis of bone marrow mesenchymal stem cells by modulating Lsm11 expression.

MicroRNAs play a critical role in bone marrow mesenchymal stem cell (MSC) chondrogenesis and regulate the progression of joint regeneration in osteoarthritis. Our previous research confirmed that miR146a relieves osteoarthritis by modulating cartilage homeostasis. However, few studies have revealed the relationship between miR146a and the chondrogenesis of MSCs, and the exact mechanisms remain unclear. This study aimed to determine the function of miR146a in the chondrogenic differentiation of MSCs and the potential mechanisms involved. MiR146a expression increased during chondrogenesis. MiR146a knockout (KO) led to the increased chondrogenesis of MSCs compared to that in wild-type (WT) MSCs, whereas the overexpression of miR146a by mimics resulted in the decreased chondrogenesis of MSCs, as determined by the mRNA expression of collagen, type II, alpha 1 (COL2A1), aggrecan, cartilage oligomeric matrix protein (COMP), and matrix metallopeptidase 13 (MMP13). Furthermore, cartilage defects could be treated better when injected with spheres induced from miR146aKO MSCs than from WT MSCs, indicating that miR146a inhibits chondrogenesis in vivo. In addition, based on miRNA-mRNA prediction analysis and a dual-luciferase reporter assay, we observed that the deletion of miR146a led to the increased expression of Lsm11 during chondrogenesis and demonstrated that miR146a targeted Lsm11 by binding to its 3'-untranslated region (UTR) and inhibited its translation. The inhibition of Lsm11 by silencing RNA (siRNA) reversed the increased ability of chondrogenesis by knocking out miR146a both in vivo and in vitro, suggesting that miR146a inhibits chondrogenesis by directly inhibiting Lsm11 in MSCs, which may be a novel target for treating osteoarthritis.

WTAP-mediated m6A modification modulates bone marrow mesenchymal stem cells differentiation potential and osteoporosis

An imbalance in the differentiation potential of bone marrow mesenchymal stem cells (BMSCs) is an important pathogenic mechanism underlying osteoporosis (OP). N6-methyladenosine (m6A) is the most common post-transcriptional modification in eukaryotic cells. The role of the Wilms’ tumor 1-associated protein (WTAP), a member of the m6A functional protein family, in regulating BMSCs differentiation remains unknown. We used patient-derived and mouse model-derived samples, qRT-PCR, western blot assays, ALP activity assay, ALP, and Alizarin Red staining to determine the changes in mRNA and protein levels of genes and proteins associated with BMSCs differentiation. Histological analysis and micro-CT were used to evaluate developmental changes in the bone. The results determined that WTAP promoted osteogenic differentiation and inhibited adipogenic differentiation of BMSCs. We used co-immunoprecipitation (co-IP), RNA immunoprecipitation (RIP), methylated RNA immunoprecipitation (MeRIP), RNA pulldown, and dual-luciferase assay to explore the direct mechanism. Mechanistically, the expression of WTAP increased during osteogenic differentiation and significantly promoted pri-miR-181a and pri-miR-181c methylation, which was recognized by YTHDC1, and increased the maturation to miR-181a and miR-181c. MiR-181a and miR-181c inhibited the mRNA expression of SFRP1, promoting the osteogenic differentiation of BMSCs. Our results demonstrated that the WTAP/YTHDC1/miR-181a and miR-181c/SFRP1 axis regulated the differentiation fate of BMSCs, suggesting that it might be a potential therapeutic target for osteoporosis.

Metformin increases bone marrow adipose tissue by promoting mesenchymal stromal cells apoptosis

Bone marrow adipose tissue (MAT) has the potential to exert both local and systemic effects on metabolic homeostasis. As a first-line drug used to treat type 2 diabetes mellitus, metformin has conflicting effects on MAT and bone marrow mesenchymal stem cell (BM-MSC) differentiation. Through a series of experiments in vivo and in vitro, we found that except improving the glucose and lipid metabolism disorder in ob/ob mice, 200 mg/kg metformin increased MAT in mice tibia, and prompted osteogenic genes (RunX2, OPN, OCN) and lipogenic genes (Ppar-γ, Cebpα, Scd1) expression in mice bone marrow. However, metformin promoted osteogenesis and inhibited lipogenesis of MSC in vitro, which is inconsistent with the results in vivo. Given MAT being considered the "filler" of the space after the apoptosis of bone marrow stroma, the effect of metformin on MSC apoptosis was examined. We discovered that metformin induces MSC apoptosis in vivo and in vitro. Therefore, we speculated that the increased MAT in mice tibia may be attributed to the filling of adipose tissue after apoptosis of bone marrow stromal cells induced by metformin. The increased MAT may be involved in the regulation of metformin on glucose, lipid, and bone metabolism in diabetic mice, providing a new way to understand the metabolic regulation of metformin. While increased MAT-associated insulin resistance and metabolic disorders may account for the poorer clinical benefits in patients with intensive glucose control.

Neuron-Glial Antigen 2 Participates in Liver Fibrosis via Regulating the Differentiation of Bone Marrow Mesenchymal Stem Cell to Myofibroblast

Neuron-glial antigen 2 (NG2, gene name: Cspg4) has been characterized as an important factor in many diseases. However, the pathophysiological relevance of NG2 in liver disease specifically regarding bone marrow mesenchymal stem cell (BMSC) differentiation to myofibroblast (MF) and the molecular details remain unknown. Human liver tissues were obtained from patients with different chronic liver diseases, and mouse liver injury models were induced by feeding a methionine-choline-deficient and high-fat diet, carbon tetrachloride administration, or bile duct ligation operation. NG2 expression was increased in human and mouse fibrotic liver and positively correlated with MF markers α-smooth muscle actin (αSMA) and other fibrotic markers in the liver. There was a co-localization between NG2 and αSMA, NG2 and EGFP (BMSC-derived MF) in the fibrotic liver determined by immunofluorescence analysis. In vitro, TGFβ1-treated BMSC showed a progressive increase in NG2 levels, which were mainly expressed on the membrane surface. Interestingly, there was a translocation of NG2 from the cell membrane into cytoplasm after the transfection of Cspg4 siRNA in TGFβ1-treated BMSC. siRNA-mediated inhibition of Cspg4 abrogated the TGFβ1-induced BMSC differentiation to MF. Importantly, inhibition of NG2 in vivo significantly attenuated the extent of liver fibrosis in methionine-choline-deficient and high fat (MCDHF) mice, as demonstrated by the decreased mRNA expression of fibrotic parameters, collagen deposition, serum transaminase levels, liver steatosis and inflammation after the administration of Cspg4 siRNA in MCDHF mice. We identify the positive regulation of NG2 in BMSC differentiation to MF during liver fibrosis, which may provide a promising target for the treatment of liver disease.

Osteogenic Efficacy of Human Trophoblasts-Derived Conditioned Medium on Mesenchymal Stem Cells.

Trophoblasts play an important role in the regulation of the development and function of the placenta. Our recent study demonstrated the skin regeneration capacity of trophoblast-derived extracellular vesicles (EV). Here, we aimed to determine the potential of trophoblast-derived conditioned medium (TB-CM) in enhancing the osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). We found that TB-CM promoted the osteogenic differentiation of MSCs in a dose-dependent manner. Furthermore, it inhibited adipogenesis of MSCs. We also found that the primary trophoblast-derived conditioned medium (PTB-CM) significantly enhanced the proliferation and osteogenic differentiation of human MSCs. Our study demonstrated the regulatory mechanisms underlying the TB-CM-induced osteogenesis in MSCs. An upregulation of genes associated with cytokines/chemokines was observed. The treatment of MSCs with TB-CM stimulated osteogenesis by activating several biological processes, such as mitogen-activated protein kinase (MAPK) and bone morphogenetic protein 2 (BMP2) signaling. This study demonstrated the proliferative and osteogenic efficacies of the trophoblast-derived secretomes, suggesting their potential for use in clinical interventions for bone regeneration and treatment.

MiR-29b Modulates Bone Marrow Mesenchymal Stem Cells (BMSCs) Differentiation and Induces Nerve Repair in Diabetic Retina Rat Model

microRNAs are involved in diabetic retinopathy (DR). This study intends to analyze miR-29b’s role in bone marrow mesenchymal stem cells (BMSCs) differentiation in DR rat models to induce nerve repair. BMSCs from DR rat models were cultured and transfected with miR-29b mimics and inhibitors followed by measuring miR-29b level, cell proliferation and apoptosis. Retinal ganglion cells (RGC) were treated with high glucose for 24 h, and BMSCs and si-miR-29b-BMSC were cocultured for 24 h, respectively followed by assessing cell proliferation and apoptosis, inflammatory cytokines by ELISA, MDA, SOD, brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) level by ELISA. MiR-29b was up-regulated in BMSCs of DR rats. miR-29b mimics significantly up-regulated miR-29b, inhibited cell proliferation and promoted apoptosis (P &lt; 0.05), which were reversed by miR-29b inhibitor (P &lt; 0.05). Co-culture of BMSCs with si-miR-29b-BMSC promoted RGC proliferation, inhibited apoptosis and IL-6 secretion, decreased MDA, increased SOD, BDNF and CNTF expression (P &lt; 0.05) with more significant changes in si-miR-29b-BMSC group (P &lt; 0.05). In conclusion, down-regulation of miR-29b promotes BMSCs proliferation in DR rat models, inhibits BMSCs apoptosis, and promotes the recovery of retinal ganglion cell function.