Downregulation of the LncRNA MEG3 Promotes Osteogenic Differentiation of BMSCs and Bone Repairing by Activating Wnt/β-Catenin Signaling Pathway

Background: Previous studies have demonstrated that long non-coding RNA maternally expressed gene 3 (MEG3) emerged as a key regulator in development and tumorigenesis. This study aims to investigate the function and mechanism of MEG3 in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and explores the use of MEG3 in skull defects bone repairing. Methods: Endogenous expression of MEG3 during BMSCs osteogenic differentiation was detected by quantitative real-time polymerase chain reaction (qPCR). MEG3 was knockdown in BMSCs by lentiviral transduction. The proliferation, osteogenic-related genes and proteins expression of MEG3 knockdown BMSCs were assessed by Cell Counting Kit-8 (CCK-8) assay, qPCR, alizarin red and alkaline phosphatase staining. Western blot was used to detect β-catenin expression in MEG3 knockdown BMSCs. Dickkopf 1 (DKK1) was used to block wnt/β-catenin pathway. The osteogenic-related genes and proteins expression of MEG3 knockdown BMSCs after wnt/β-catenin inhibition were assessed by qPCR, alizarin red and alkaline phosphatase staining. MEG3 knockdown BMSCs scaffold with PHMG were implanted in a critical-sized skull defects of rat model. Micro-computed tomography(micro-CT), hematoxylin and eosin staining and immunohistochemistry were performed to evaluate the bone repairing. Results: Endogenous expression of MEG3 was increased during osteogenic differentiation of BMSCs. Downregulation of MEG3 could promote osteogenic differentiation of BMSCs in vitro. Notably, a further mechanism study revealed that MEG3 knockdown could activate Wnt/β-catenin signaling pathway in BMSCs. Wnt/β-catenin inhibition would impair MEG3-induced osteogenic differentiation of BMSCs. By using poly (3-hydroxybutyrate-co-3-hydroxyhexanoate, PHBHHx)-mesoporous bioactive glass (PHMG) scaffold with MEG3 knockdown BMSCs, we found that downregulation of MEG3 in BMSCs could accelerate bone repairing in a critical-sized skull defects rat model. Conclusions: Our study reveals the important role of MEG3 during osteogenic differentiation and bone regeneration. Thus, MEG3 engineered BMSCs may be effective potential therapeutic targets for skull defects.

miR-125a-5p Regulates Osteogenic Differentiation of Human Adipose-Derived Mesenchymal Stem Cells under Oxidative Stress

Adipose-derived mesenchymal stem cells (ADSCs) are a well-recognized multilineage stem cell with vital clinical feasibility for tissue regeneration. Extensive evidence indicates that oxidative stress and microRNAs (miRNAs/miRs) play an important role in the osteoinduction of adipose-derived mesenchymal stem cells. In this study, we investigated the mechanism of miR-125a-5p in regulating the osteogenesis of human adipose-derived mesenchymal stem cells (hADSCs) under oxidative stress. The expression of miR-125a-5p lessened gradually during the osteogenic differentiation of hADSCs. Relative to the negative group, the expression levels of runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OCN), and osterix in the miR-125a-5p group were marked lower than those in the miR-125a-5p inhibitor group. The levels of p16, p21, p53, miR-125a-5p, and ROS during osteoinduction of hADSCs were assessed in vitro under oxidative stress and were observed to be upregulated. Further experiments showed that oxidative stress and miR-125a-5p together suppressed the expression of VEGF during osteogenic differentiation of hADSCs and that the inhibition of miR-125a-5p reversed the effect of oxidative stress. In short, our study indicated that miR-125a-5p is induced under oxidative stress and inhibits the expression of VEGF, leading to the reduction of osteogenic differentiation of hADSCs. Our outcomes showed that miR-125a-5p could be a potential clinical target for bone repairing.

Pearl Powder—An Emerging Material for Biomedical Applications: A Review

Pearl powder is a well-known traditional Chinese medicine for a variety of indications from beauty care to healthcare. While used for over a thousand years, there has yet to be an in-depth understanding and review in this area. The use of pearl powder is particularly growing in the biomedical area with various benefits reported due to the active ingredients within the pearl matrix itself. In this review, we focus on the emerging biomedical applications of pearl powder, touching on applications of pearl powder in wound healing, bone repairing, treatment of skin conditions, and other health indications.

Downregulation of the long non-coding RNA MEG3 promotes osteogenic differentiation of BMSCs and bone repairing by activating Wnt/β-catenin signaling pathway

Background: Previous studies have demonstrated long non-coding RNA maternally expressed gene 3 (MEG3) emerged as a key regulator in development and tumorigenesis. However, whether MEG3 participate in osteogenic differentiation and bone regeneration remains unclear. This study aims to investigate the function and mechanism of MEG3 in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and explores the use of MEG3 in skull defects bone repairing. Methods: Endogenous expression of MEG3 during BMSCs osteogenic differentiation were detected by qPCR. MEG3 was knockdown in BMSCs by lentivirus. The proliferation, osteogenic-related genes and proteins expression were assessed by the CCK-8, PCR, alizarin red and alkaline phosphatase staining in MEG3 knockdown BMSCs. Western blot was used to detected β-catenin expression in MEG3 knockdown BMSCs. DKK1 was used to block wnt/β-catenin pathway, the osteogenic-related genes and proteins expression were assessed by PCR, alizarin red and alkaline phosphatase staining in MEG3 knockdown BMSCs. MEG3 knockdown BMSCs scaffold with PHMG were implanted in a critical-sized skull defects of rat model, micro-CT, hematoxylin and eosin staining, and immunohistochemistry were performed to evaluate the bone repairing. Results: MEG3 was increased during osteogenic differentiation of BMSCs. Downregulation of MEG3 could promote osteogenic differentiation of BMSCs in vitro. Notably, a further mechanism study revealed MEG3 knockdown could activate Wnt/β-catenin signaling pathway in BMSCs. Wnt/β-catenin inhibition would impair MEG3-induced osteogenic differentiation of BMSCs. By using PHMG scaffold with MEG3 knockdown BMSCs, we found that downregulation of MEG3 in BMSCs could accelerated bone repairing in a critical-sized skull defects rat model. Conclusions: Our study reveals the important role of MEG3 during osteogenic differentiation and bone regeneration. Thus, MEG3 engineered BMSCs may be effective potential therapeutic targets for skull defects.

The preparation and application of calcium phosphate biomedical composites in filling of weight-bearing bone defects

Nowadays, artificial bone materials have been widely applied in the filling of non-weight bearing bone defects, but scarcely ever in weight-bearing bone defects. This study aims to develop an artificial bone with excellent mechanical properties and good osteogenic capability. Firstly, the collagen-thermosensitive hydrogel-calcium phosphate (CTC) composites were prepared as follows: dissolving thermosensitive hydrogel at 4 °C, then mixing with type I collagen as well as tricalcium phosphate (CaP) powder, and moulding the composites at 37 °C. Next, the CTC composites were subjected to evaluate for their chemical composition, micro morphology, pore size, Shore durometer, porosity and water absorption ability. Following this, the CTC composites were implanted into the muscle of mice while the 70% hydroxyapatite/30% β-tricalcium phosphate (HA/TCP) biomaterials were set as the control group; 8 weeks later, the osteoinductive abilities of biomaterials were detected by histological staining. Finally, the CTC and HA/TCP biomaterials were used to fill the large segments of tibia defects in mice. The bone repairing and load-bearing abilities of materials were evaluated by histological staining, X-ray and micro-CT at week 8. Both the CTC and HA/TCP biomaterials could induce ectopic bone formation in mice; however, the CTC composites tended to produce larger areas of bone and bone marrow tissues than HA/TCP. Simultaneously, bone-repairing experiments showed that HA/TCP biomaterials were easily crushed or pushed out by new bone growth as the material has a poor hardness. In comparison, the CTC composites could be replaced gradually by newly formed bone and repair larger segments of bone defects. The CTC composites trialled in this study have better mechanical properties, osteoinductivity and weight-bearing capacity than HA/TCP. The CTC composites provide an experimental foundation for the synthesis of artificial bone and a new option for orthopedic patients.