Exosomal miRNA-455 from Bone Marrow Stromal Cells (BMSCs) Promotes Macrophage Phagocytosis and Restrains Progression of Gastric Cancer (GC)

Multiple miRNAs are differentially expressed in gastric cancer (GC). Herein, this study aims to investigate miR-455’s role in GC and its mechanism. Exosomes (exo) separated from BMSCs after transfection were co-cultured with either phagocytes, GC cells (NCI-N87 cell), or macrophages combined with NCI-N87cells (mixed group) followed by analysis of the expression of PTEN, N-cadherin, E-cadherin, and PI3K, and AKT by RT-qPCR and Western blot. Increased miR-455 expression was observed in GC cells upon transfection. GC cells in the mixed group relative to NCI-N87 group exhibited a lower cell migration and invasion and impaired proliferative capacity (p < 0.05), accompanied with higher expressions of N-cadherin, E-cadherin, PI3K, and AKT, and decreased level of PTEN (p < 0.05). The combined treatment resulted in a higher phagocytic rate (12.38±0.21%) and phagocytic index (14.29±2.11%) compared to treatment with only phagocytes (p < 0.05). In conclusion, BMSC-derived exosomal miR-455 inhibits the growth of GC cells and promotes the phagocytosis through inactivating PI3K/AKT signaling pathway.

Bone Marrow Stromal Cells Promotes Morphological Senescence of Prostate Cancer Cells and Inhibits Metastasis Associated 1 Gene Level

This study assessed the mechanism of Bone Marrow Stromal Cells (BMSCs) in prostate cancer (PC) and its effect on MTA-1 gene and PC cell senescence. PC-3 cells were assigned into QL group (prostate cancer group: normal culture) and GS group (BMSCs group: treated with BMSCs) followed by analysis of MTA-1 level, cell senescence, apoptosis and invasion. MTA-1 level in QL group (0.83±0.07) was significantly higher than GS group (0.14±0.02) (P < 0.05), indicating that BMSCs had an inhibitory effect on MTA-1 expression. Similar change of MTA-l mRNA was also found with higher level in QL group than GS group (P < 0.05). Cell senescence was found in QS group but not QL group, indicating that BMSCs promote cell senescence. Compared with GS group, QL group has a higher cell number in G0/G1 (67.13±6.45%) and S (19.59±3.35%) than GS group (G0/G1:50.51±2.19% and S: 11.42±1.61%) but lower G2/M (QL: 15.97±3.59% versus GS: 32.25±3.24%). QL group had significantly lower cell apoptosis rate at 35 h (5.21±1.2%) and 45 h (3.97±0.95%) than GS group at 35 h (17.85±1.23%), 45 h (10.21±1.26%) with elevated number of invasions. In conclusion, BMSCs promote PC-3 cell senescence and apoptosis by inhibiting the expression of MTA-1 and reduce cell invasion ability.

Heparin Enriched-WPI Coating on Ti6Al4V Increases Hydrophilicity and Improves Proliferation and Differentiation of Human Bone Marrow Stromal Cells

Titanium alloy (Ti6Al4V) is one of the most prominent biomaterials for bone contact because of its ability to bear mechanical loading and resist corrosion. The success of Ti6Al4V implants depends on bone formation on the implant surface. Hence, implant coatings which promote adhesion, proliferation and differentiation of bone-forming cells are desirable. One coating strategy is by adsorption of biomacromolecules. In this study, Ti6Al4V substrates produced by additive manufacturing (AM) were coated with whey protein isolate (WPI) fibrils, obtained at pH 2, and heparin or tinzaparin (a low molecular weight heparin LMWH) in order to improve the proliferation and differentiation of bone-forming cells. WPI fibrils proved to be an excellent support for the growth of human bone marrow stromal cells (hBMSC). Indeed, WPI fibrils were resistant to sterilization and were stable during storage. This WPI-heparin-enriched coating, especially the LMWH, enhanced the differentiation of hBMSC by increasing tissue non-specific alkaline phosphatase (TNAP) activity. Finally, the coating increased the hydrophilicity of the material. The results confirmed that WPI fibrils are an excellent biomaterial which can be used for biomedical coatings, as they are easily modifiable and resistant to heat treatments. Indeed, the already known positive effect on osteogenic integration of WPI-only coated substrates has been further enhanced by a simple adsorption procedure.

miR-6315 Attenuates Methotrexate Treatment-Induced Decreased Osteogenesis and Increased Adipogenesis Potentially through Modulating TGF-β/Smad2 Signalling

Methotrexate (MTX) treatment for childhood malignancies has shown decreased osteogenesis and increased adipogenesis in bone marrow stromal cells (BMSCs), leading to bone loss and bone marrow adiposity, for which the molecular mechanisms are not fully understood. Currently, microRNAs (miRNAs) are emerging as vital mediators involved in bone/bone marrow fat homeostasis and our previous studies have demonstrated that miR-6315 was upregulated in bones of MTX-treated rats, which might be associated with bone/fat imbalance by directly targeting Smad2. However, the underlying mechanisms by which miR-6315 regulates osteogenic and adipogenic differentiation require more investigations. Herein, we further explored and elucidated the regulatory roles of miR-6315 in osteogenesis and adipogenesis using in vitro cell models. We found that miR-6315 promotes osteogenic differentiation and it alleviates MTX-induced increased adipogenesis. Furthermore, our results suggest that the involvement of miR-6315 in osteogenesis/adipogenesis regulation might be partially through modulating the TGF-β/Smad2 signalling pathway. Our findings indicated that miR-6315 may be important in regulating osteogenesis and adipogenesis and might be a therapeutic target for preventing/attenuating MTX treatment-associated bone loss and marrow adiposity.

Clinical Outcome and 8-Year Follow-Up of Alveolar Bone Tissue Engineering for Severely Atrophic Alveolar Bone Using Autologous Bone Marrow Stromal Cells with Platelet-Rich Plasma and β-Tricalcium Phosphate Granules

Background: Although bone tissue engineering for dentistry has been studied for many years, the clinical outcome for severe cases has not been established. Furthermore, there are limited numbers of studies that include long-term follow-up. In this study, the safety and efficacy of bone tissue engineering for patients with a severely atrophic alveolar bone were examined using autogenous bone marrow stromal cells (BMSCs), and the long-term stability was also evaluated. Methods: BMSCs from iliac bone marrow aspirate were cultured and expanded. Then, induced osteogenic cells were transplanted with autogenous platelet-rich plasma (PRP) and β-tricalcium phosphate granules (β-TCP) for maxillary sinus floor and alveolar ridge augmentation. Eight patients (two males and six females) with an average age of 54.2 years underwent cell transplantation. Safety was assessed by monitoring adverse events. Radiographic evaluation and bone biopsies were performed to evaluate the regenerated bone. Results: The major population of transplanted BMSCs belonged to the fraction of CD34−, CD45dim, and CD73+ cells, which was only 0.065% of the total bone marrow cells. Significant deviations were observed in cell growth and alkaline phosphatase activities among individuals. However, bone regeneration was observed in all patients and the average bone area in the biopsy samples was 41.9% 6 months following transplantation, although there were also significant deviations among each case. No adverse events related to the transplants were observed. In the regenerated bone, 27 out of 29 dental implants were integrated. Dental implants and regenerated bone were stable for an average follow-up period of 7 years and 10 months. Conclusions: Although individual variations were observed, the results showed that bone tissue engineering using BMSCs with PRP and β-TCP was feasible for patients with severe atrophic maxilla throughout a long-term follow-up period and was considered safe. However, further studies with a larger number of cases and controls to confirm the efficacy of BMSCs and the development of a protocol to establish a reproducible quality of stem cell-based graft material will be required.

Effects of Bone Marrow Stromal Cells (BMSCs) on Behavior, Infarct Size and HIF-1α Expression in Stroke Rats

This study aims to assess BMSCs’ effect on the behavior, infarct size and HIF-1α expression in stroke rats. Rats were separated into sham group, CVA group and BMSCs group with 10 rats in each group followed by analysis of neuroethology scores, brain tissue pathology and infarct size, and HIF-1α level in brain tissues. No difference of neurological scores was found between CVA group and BMSCs group after 3 hours (P > 0.05). After BMSCs transplantation, the nerve score was significantly reduced (P < 0.05) and cognitive function was significantly improved compared to CVA group. Compared with sham rats, CAV rats had a larger area of infarction and the infarcted tissue cells showed degeneration or necrosis with reduced cell number and obvious edema, which were all improved in BMSCs group. CVA group showed a larger area of infarct tissue (P < 0.05), which was reduced in BMSCs group (P < 0.05). Compared with sham group, CVA group showed significantly upregulated HIF-1α level (P < 0.05) which was reduced in BMSCs group (P < 0.05). BMSCs has a certain repair effect on the ethology of stroke rats possibly via inhibition of HIF-1α level in cerebral infarction and brain tissue.

Development of a Bone-Mimetic 3D Printed Ti6Al4V Scaffold to Enhance Osteoblast-Derived Extracellular Vesicles’ Therapeutic Efficacy for Bone Regeneration

Extracellular Vesicles (EVs) are considered promising nanoscale therapeutics for bone regeneration. To date, EVs are typically procured from cells on 2D tissue culture plastic, an artificial environment that limits cell growth and does not replicate in situ biochemical or biophysical conditions. This study investigated the potential of 3D printed titanium scaffolds coated with hydroxyapatite to promote the therapeutic efficacy of osteoblast-derived EVs. Ti6Al4V titanium scaffolds with different pore sizes (500 and 1000 µm) and shapes (square and triangle) were fabricated by selective laser melting. A bone-mimetic nano-needle hydroxyapatite (nnHA) coating was then applied. EVs were procured from scaffold-cultured osteoblasts over 2 weeks and vesicle concentration was determined using the CD63 ELISA. Osteogenic differentiation of human bone marrow stromal cells (hBMSCs) following treatment with primed EVs was evaluated by assessing alkaline phosphatase activity, collagen production and calcium deposition. Triangle pore scaffolds significantly increased osteoblast mineralisation (1.5-fold) when compared to square architectures (P ≤ 0.001). Interestingly, EV yield was also significantly enhanced on these higher permeability structures (P ≤ 0.001), in particular (2.2-fold) for the larger pore structures (1000 µm). Furthermore osteoblast-derived EVs isolated from triangular pore scaffolds significantly increased hBMSCs mineralisation when compared to EVs acquired from square pore scaffolds (1.7-fold) and 2D culture (2.2-fold) (P ≤ 0.001). Coating with nnHA significantly improved osteoblast mineralisation (&gt;2.6-fold) and EV production (4.5-fold) when compared to uncoated scaffolds (P ≤ 0.001). Together, these findings demonstrate the potential of harnessing bone-mimetic culture platforms to enhance the production of pro-regenerative EVs as an acellular tool for bone repair.

Bone-Forming Peptide-4 Induces Osteogenic Differentiation and VEGF Expression on Multipotent Bone Marrow Stromal Cells

Bone morphogenetic proteins (BMPs) have been widely used as treatment for bone repair. However, clinical trials on fracture repair have challenged the effectiveness of BMPs and suggested that delivery of multipotent bone marrow stromal cells (BMSCs) might be beneficial. During bone remodeling and bone fracture repair, multipotent BMSCs differentiate into osteoblasts or chondrocytes to stimulate bone formation and regeneration. Stem cell-based therapies provide a promising approach for bone formation. Extensive research has attempted to develop adjuvants as specific stimulators of bone formation for therapeutic use in patients with bone resorption. We previously reported for the first time bone-forming peptides (BFPs) that induce osteogenesis and bone formation. BFPs are also a promising osteogenic factor for prompting bone regeneration and formation. Thus, the aim of the present study was to investigate the underlying mechanism of a new BFP-4 (FFKATEVHFRSIRST) in osteogenic differentiation and bone formation. This study reports that BFP-4 induces stronger osteogenic differentiation of BMSCs than BMP-7. BFP-4 also induces ALP activity, calcium concentration, and osteogenic factors (Runx2 and osteocalcin) in a dose dependent manner in BMSCs. Therefore, these results indicate that BFP-4 can induce osteogenic differentiation and bone formation. Thus, treatment of multipotent BMSCs with BFP-4 enhanced osteoblastic differentiation and displayed greater bone-forming ability than BMP-7 treatment. These results suggest that BFP-4-stimulated cell therapy may be an efficient and cost-effective complement to BMP-7-based clinical therapy for bone regeneration and formation.