Bone Mesenchymal Stem Cells (BMSCs) Transplantation Can Repair Rat Femoral Head Necrosis and Inhibit the Expression of Omgp

To study the therapeutic effect of BMSCs on femoral head necrosis and whether it can inhibit the growth of OMgP. 15 healthy rats were divided into ZZ group (normal group), GT group (femoral head necrosis) and MM group (BMSCs transplantation). At 1 h, 3 h, 1 d, and 3 d, the expression of OMgP in GT group were higher than ZZ group (P <0.05) and MM group, indicating that BMSCs transplantation can decreased OMgP expression. At 1 d, 7 d, and 14 d, BBB scores of the GT group were lower than ZZ group (P < 0.05) and MM group (P < 0.05), indicating that BMSCs transplantation can improve spinal cord injury behavior. The cells in ZZ group were well stained and morphologically intact, the femoral head was not damaged, and the articular surface was smooth, GT group had cartilage necrosis with disordered inferior epiphysis, and the femoral head of the MM group had less damage and increased osteoblasts. The blood vessel counts in necrotic area in GT group were higher than ZZ group and MM group with decreased new bone area in repair area compared to ZZ and MM group (P <0.05), indicating that the area of femoral head necrosis after BMSCs transplantation was improved. The levels of ALP and BGP in GT group were lower than ZZ group (P <0.05) and MM group (P <0.05). Bone marrow mesenchymal stem cell transplantation can effectively repair new bone area, up-regulate ALP and BGP, and have a positive effect on femoral head necrosis, possibly by inhibiting OMGP activity.

Macrophage-Derived Exosomes Promote Bone Mesenchymal Stem Cells Towards Osteoblastic Fate Through microRNA-21a-5p

The effective healing of a bone defect is dependent on the careful coordination of inflammatory and bone-forming cells. In the current work, pro-inflammatory M1 and anti-inflammatory M2 macrophages were co-cultured with primary murine bone mesenchymal stem cells (BMSCs), in vitro, to establish the cross-talk among polarized macrophages and BMSCs, and as well as their effects on osteogenesis. Meanwhile, macrophages influence the osteogenesis of BMSCs through paracrine forms such as exosomes. We focused on whether exosomes of macrophages promote osteogenic differentiation. The results indicated that M1 and M2 polarized macrophage exosomes all can promote osteogenesis of BMSCs. Especially, M1 macrophage-derived exosomes promote osteogenesis of BMSCs through microRNA-21a-5p at the early stage of inflammation. This research helps to develop an understanding of the intricate interactions among BMSCs and macrophages, which can help to improve the process of bone healing as well as additional regenerative processes by local sustained release of exosomes.

Nanoscale Modification of Titanium Implants Improves Behaviors of Bone Mesenchymal Stem Cells and Osteogenesis In Vivo

The surficial micro/nanotopography and physiochemical properties of titanium implants are essential for osteogenesis. However, these surface characters’ influence on stem cell behaviors and osteogenesis is still not fully understood. In this study, titanium implants with different surface roughness, nanostructure, and wettability were fabricated by further nanoscale modification of sandblasted and acid-etched titanium (SLA: sandblasted and acid-etched) by H2O2 treatment (hSLAs: H2O2 treated SLA). The rat bone mesenchymal stem cells (rBMSCs: rat bone mesenchymal stem cells) are cultured on SLA and hSLA surfaces, and the cell behaviors of attachment, spreading, proliferation, and osteogenic differentiation are further analyzed. Measurements of surface characteristics show hSLA surface is equipped with nanoscale pores on microcavities and appeared to be hydrophilic. In vitro cell studies demonstrated that the hSLA titanium significantly enhances cell response to attachment, spreading, and proliferation. The hSLAs with proper degree of H2O2 etching (h1SLA: treating SLA with H2O2 for 1 hour) harvest the best improvement of differentiation of rBMSCs. Finally, the osteogenesis in beagle dogs was tested, and the h1SLA implants perform much better bone formation than SLA implants. These results indicate that the nanoscale modification of SLA titanium surface endowing nanostructures, roughness, and wettability could significantly improve the behaviors of bone mesenchymal stem cells and osteogenesis on the scaffold surface. These nanoscale modified SLA titanium scaffolds, fabricated in our study with enhanced cell affinity and osteogenesis, had great potential for implant dentistry.

Systematic Analysis of mRNAs and ncRNAs in BMSCs of Senile Osteoporosis Patients

Senile osteoporosis (SOP) is a worldwide age-related disease characterized by the loss of bone mass and decrease in bone strength. Bone mesenchymal stem cells (BMSCs) play an important role in the pathology of senile osteoporosis. Abnormal expression and regulation of non-coding RNA (ncRNA) are involved in a variety of human diseases. In the present study, we aimed to identify differentially expressed mRNAs and ncRNAs in senile osteoporosis patient-derived BMSCs via high-throughput transcriptome sequencing in combination with bioinformatics analysis. As a result, 415 mRNAs, 30 lncRNAs, 6 circRNAs and 27 miRNAs were found to be significantly changed in the senile osteoporosis group. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were applied to analyze the function of differentially expressed mRNAs and ncRNAs. The circRNA–miRNA–mRNA regulatory network was constructed using the cytoHubba plugin based on the Cytoscape software. Interestingly, circRNA008876-miR-150-5p-mRNA was the sole predicted circRNA-miRNA-mRNA network. The differential expression profile of this ceRNA network was further verified by qRT-PCR. The biological function of this network was validated by overexpression and knockdown experiments. In conclusion, circRNA008876-miR-150-5p-mRNA could be an important ceRNA network involved in senile osteoporosis, which provides potential biomarkers and therapeutic targets for senile osteoporosis.

MiR-26b-5p Promotes Osteogenesis of Bone Mesenchymal Stem Cells via Suppressing FGF21

Introduction: It has been established that miR-26b-5p actively participate in the osteogenic differentiation of bone mesenchymal stem cells (BMSCs), which is of great value in osteoporosis treatment. Database showed that Fibroblast growth factor(FGF)21 is a potential binding site of miR-26b-5p. This study aimed to investigate the molecular osteogenic mechanisms of miR-26b-5p targeting FGF21 in postmenopausal osteoporosis (PMOP). Methods: 5ml of bone marrow was aspirated from the anterior superior iliac spine in 10 PMOP women during bone marrow puncture. BMSCs were used to establish an in vitro cell model, and BMSCs markers were analyzed by flow cytometry. miR-26b-5p and FGF21 were overexpressed for 48h, and then placed in an osteogenic induction medium for osteogenic induction culture, the expression of RNA was detect using RT-qPCR. Cells from miR-26b-5p group were collected on days 7, 14 and 21 of induction for ALP and alizarin red S staining. On day 7 of induction, RT-qPCR was used to measure Runx2, Osterix (Osx), and target gene FGF21 expression levels in each group. The dual-luciferase reporter gene system was used to verify that FGF21 was a direct target of miR-26b-5p. FGF21 was measured by western blotting in the miR-26b-5p overexpression group and in the miR-26b-5p inhibition group. Results: BMSCs were identified according with the antigenic characteristics. miR-26b-5p expression was significantly upregulated after the expression of miR-26b-5p mimics; however, FGF21 expression was downregulated after FGF21 mimics. After overexpression of miR-26b-5p, the alkaline phosphatase activity and nodules of alizarin red S in the culture medium gradually increased as the induction time increased. RT-qPCR showed that the expressions of master osteogenic factors Runx2 and Osx in the BMSC+ osteogenic differentiation medium group was significantly higher than in the BMSC group, the expressions of the factors in the BMSC+ miR-26b-5p overexpression group was significantly higher than in the control group. Target gene FGF21 expression was significantly lower in the BMSC+ osteogenic differentiation medium group than in the BMSC group, and was significantly lower in the BMSC+ miR-26b-5p overexpression group than in the control group. Luciferase reporter assays demonstrated that FGF21 was a direct target of miR-26b-5p. Finally, western blotting analysis showed that FGF21 expression was significantly downregulated in the miR-26b-5p overexpressed group and upregulated in the miR-26b-5p inhibition group. Conclusion: miR-26b-5p can regulate the osteogenic differentiation of BMSCs and participate in PMOP pathogenesis via suppressing FGF21. The present study provides the basis for further studies on PMOP.

Improved Osteogenesis by Mineralization Combined With Double-Crosslinked Hydrogel Coating for Proliferation and Differentiation of Mesenchymal Stem Cells

In consideration of improving the interface problems of poly-L-lactic acid (PLLA) that hindered biomedical use, surface coatings have been explored as an appealing strategy in establishing a multi-functional coating for osteogenesis. Though the layer-by-layer (LBL) coating developed, a few studies have applied double-crosslinked hydrogels in this technique. In this research, we established a bilayer coating with double-crosslinked hydrogels [alginate–gelatin methacrylate (GelMA)] containing bone morphogenic protein (BMP)-2 [alginate-GelMA/hydroxyapatite (HA)/BMP-2], which displayed great biocompatibility and osteogenesis. The characterization of the coating showed improved properties and enhanced wettability of the native PLLA. To evaluate the biosafety and inductive ability of osteogenesis, the behavior (viability, adherence, and proliferation) and morphology of human bone mesenchymal stem cells (hBMSCs) on the bilayer coatings were tested by multiple exams. The satisfactory function of osteogenesis was verified in bilayer coatings. We found the best ratios between GelMA and alginate for biological applications. The Alg70-Gel30 and Alg50-Gel50 groups facilitated the osteogenic transformation of hBMSCs. In brief, alginate-GelMA/HA/BMP-2 could increase the hBMSCs’ early transformation of osteoblast lineage and promote the osteogenesis of bone defect, especially the outer hydrogel layer such as Alg70-Gel30 and Alg50-Gel50.

Exosomes Derived from Platelet-Rich Plasma Administration in Site Mediate Cartilage Protection in Subtalar Osteoarthritis

Subtalar osteoarthritis (STOA) is often secondary to chronic ankle sprains, which seriously affects the quality of life of patients. Due to its etiology and pathogenesis was not studied equivocally yet, there is currently a lack of effective conservative treatments. Although they have been used for tissue repair, platelet-rich plasma-derived exosomes (PRP-Exo) have the disadvantage of low retention and short-lived therapeutic effects. This study aimed to determine whether incorporation of PRP-Exo in thermosensitive hydrogel (Gel) increased their retention in the joint and thereby playing a therapeutic role on STOA due to chronic mechanical instability established by transecting lateral ligaments (anterior talofibular ligament (ATFL) / calcaneal fibular ligament (CFL)). PRP-Exo incorporated Gel (Exo-Gel) system, composed of Poloxamer-407 and 188 mixture-based thermoresponsive hydrogel matrix in an optimal ratio, was determined by its release ability of Exo and rheology of Gel response to different temperature. The biological activity of Exo-Gel was evaluated in vitro, and the therapeutic effect of Exo-Gel on STOA was evaluated in vivo. Exo released from Exo-Gel continuously for 28 days could promote the proliferation and migration of mouse bone mesenchymal stem cells (mBMSCs) and chondrocytes, at the same time enhance the chondrogenic differentiation of mBMSCs, and inhibit inflammation-induced chondrocyte degeneration. In vivo experiments confirmed that Exo-Gel increased the local retention of Exo, inhibited the apoptosis and hypertrophy of chondrocytes, enhanced their proliferation, and potentially played the role in stem cell recruitment to delay the development of STOA. Thus, Delivery of PRP-Exo incorporated in thermosensitive Gel provides a novel approach of cell-free therapy and has therapeutic effect on STOA.

Chitin Nerve Conduits with Three-Dimensional Spheroids of Mesenchymal Stem Cells from SD Rats Promote Peripheral Nerve Regeneration

Peripheral nerve injury (PNI) is an unresolved medical problem with limited therapeutic effects. Epineurium neurorrhaphy is an important method for the treatment of PNI in clinical application, but it is accompanied by inevitable complications such as the misconnection of nerve fibers and neuroma formation. Conduits small gap tubulization has been proved to be an effective suture method to replace the epineurium neurorrhaphy. In this study, a chitin conduit was used to bridge the peripheral nerve stumps. The micromorphology, mechanical property, and biocompatibility of chitin conduits were characterized. The results showed chitin was a high-quality biological material for constructing nerve conduits. In addition, previous reports demonstrated that mesenchymal stem cells culture as spheroids can improve the therapeutic potential. In the present study, we used a hanging drop protocol to prepare bone mesenchymal stem cells (BMSCs) spheroids. Meanwhile, spherical stem cells could express higher stemness-related genes. In the PNI rat models with small gap tubulization, the transformation of BMSCs spheroids, but not BMSCs monolayer, improved sciatic nerve regeneration. Therefore, combining BMSCs spheroids with chitin nerve conduits shows application potential in promoting peripheral nerve regeneration.