Juglans regia L. extract promotes osteogenesis of human bone marrow mesenchymal stem cells through BMP2/Smad/Runx2 and Wnt/β-catenin pathways

Crosstalk between Wnt and bone morphogenetic protein signaling during osteogenic differentiation

Mesenchymal stem cells (MSCs) originate from many sources, including the bone marrow and adipose tissue, and differentiate into various cell types, such as osteoblasts and adipocytes. Recent studies on MSCs have revealed that many transcription factors and signaling pathways control osteogenic development. Osteogenesis is the process by which new bones are formed; it also aids in bone remodeling. Wnt/β-catenin and bone morphogenetic protein (BMP) signaling pathways are involved in many cellular processes and considered to be essential for life. Wnt/β-catenin and BMPs are important for bone formation in mammalian development and various regulatory activities in the body. Recent studies have indicated that these two signaling pathways contribute to osteogenic differentiation. Active Wnt signaling pathway promotes osteogenesis by activating the downstream targets of the BMP signaling pathway. Here, we briefly review the molecular processes underlying the crosstalk between these two pathways and explain their participation in osteogenic differentiation, emphasizing the canonical pathways. This review also discusses the crosstalk mechanisms of Wnt/BMP signaling with Notch- and extracellular-regulated kinases in osteogenic differentiation and bone development.

Hypoxia inducible factor-1α related mechanism and TCM intervention in process of early fracture healing

As a common clinical disease, fracture is often accompanied by pain, swelling, bleeding as well as other symptoms and has a high disability rate, even threatening life, seriously endangering patients' physical and psychological health and quality of life. Medical practitioners take many strategies for the treatment of fracture healing, including Traditional Chinese Medicine (TCM). In the early stage of fracture healing, the local fracture is often in a state of hypoxia, accompanied by the expression of hypoxia inducible factor-1α (HIF-1α), which is beneficial to wound healing. Through literature mining, we thought that hypoxia, HIF-1α and downstream factors affected the mechanism of fracture healing, as well as dominated this process. Therefore, we reviewed the local characteristics and related signaling pathways involved in the fracture healing process and summarized the intervention of TCM on these mechanisms, in order to inspirit the new strategy for fracture healing, as well as elaborate on the possible principles of TCM in treating fractures based on the HIF molecular mechanism.

Attributes of Nanomaterials and Nanotopographies for Improved Bone Tissue Engineering and Regeneration

Bone tissue engineering (BTE) is a multidisciplinary area that can solve the limitation of conventional grafting methods by developing viable and biocompatible bone replacements. The three essential components of BTE, i.e., Scaffold material and Cells and Growth factors altogether, facilitate support and guide for bone formation, differentiation of the bone tissues, and enhancement in the cellular activities and bone regeneration. However, there is a scarcity of the appropriate materials that can match the mechanical property as well as functional similarity to native tissue, considering the bone as hard tissue. In such scenarios, nanotechnology can be leveraged upon to achieve the desired aspects of BTE, and that is the key point of this review article. This review article examines the significant areas of nanotechnology research that have an impact on regeneration of bone: (a) scaffold with nanomaterials helps to enhance physicochemical interactions, biocompatibility, mechanical stability, and attachment; (b) nanoparticle-based approaches for delivering bioactive chemicals, growth factors, and genetic material. The article begins with the introduction of components and healing mechanisms of bone and the factors associated with them. The focus of this article is on the various nanotopographies that are now being used in scaffold formation, by describing how they are made, and how these nanotopographies affect the immune system and potential underlying mechanisms. The advantages of 4D bioprinting in BTE by using nanoink have also been mentioned. Additionally, we have investigated the importance of an in silico approach for finding the interaction between drugs and their related receptors, which can help to formulate suitable systems for delivery. This review emphasizes the role of nanoscale approach and how it helps to increase the efficacy of parameters of scaffold as well as drug delivery system for tissue engineering and bone regeneration.

Extracellular vesicles derived from bone marrow mesenchymal stem cells loaded on magnetic nanoparticles delay the progression of diabetic osteoporosis via delivery of miR-150-5p

Extracellular vesicles derived from bone marrow mesenchymal stem cells (BMSC-EVs) are emerged as carriers of therapeutic targets against bone disorders, yet its isolation and purification are limited with recent techniques. Magnetic nanoparticles (MNPs) can load EVs with a unique targeted drug delivery system. We constructed gold-coated magnetic nanoparticles (GMNPs) by decorating the surface of the Fe3O4@SiO2 core and a silica shell with poly(ethylene glycol) (PEG)-aldehyde (CHO) and examined the role of BMSC-EVs loaded on GMNPs in diabetic osteoporosis (DO). The osteoporosis-related differentially expressed miR-150-5p was singled out by microarray analysis. DO models were then established in Sprague-Dawley rats by streptozotocin injection, where poor expression of miR-150-5p was validated in the bone tissues. Next, GMNPE was prepared by combining GMNPs with anti-CD63, after which osteoblasts were co-cultured with the GMNPE-BMSC-EVs. The re-expression of miR-150-5p facilitated osteogenesis in osteoblasts. GMNPE could promote the enrichment of EVs in the bone tissues of DO rats. BMSC-EVs delivered miR-150-5p to osteoblasts, where miR-150-5p targeted MMP14 and consequently activated Wnt/β-catenin pathway. This effect contributed to the enhancement of osteoblast proliferation and maturation. Furthermore, GMNPE enhanced the EV-based delivery of miR-150-5p to regulate the MMP14/Wnt/β-catenin axis, resulting in promotion of osteogenesis. Overall, our findings suggest the potential of GMNP-BMSC-EVs to strengthen osteoblast proliferation and maturation in DO, showing promise as an appealing drug delivery strategy against DO. 1. GMNPs-BMSCs-EVs-miR-150-5p promotes the osteogenesis of DO rats. 2. miR-150-5p induces osteoblast proliferation and maturation by targeting MMP14. 3. Inhibition of MMP14 activates Wnt/β-catenin and increases osteogenesis. 4. miR-150-5p activates the Wnt/β-catenin pathway by downregulating MMP14.

YTHDC2 inhibits rat bone mesenchymal stem cells osteogenic differentiation by accelerating RUNX2 mRNA degradation via m6A methylation

As the most abundant internal mRNA modification, N6-methyladenosine (m6A) RNA methylation has been found to influence many biological events including bone mesenchymal stem cells (BMSCs) osteogenic differentiation. YTH N6-methyladenosine RNA binding protein C2 （YTHDC2） is an m6A reading protein with the ability to mediate the decay of combined methylated mRNA, however its role in BMSCs osteogenic differentiation remains unknown. In this study, we first found an increase of RUNX family transcription factor 2 （RUNX2） expression and a decrease of YTHDC2 expression during the process of BMSCs osteogenic differentiation. Furthermore, we transfected BMSCs with YTHDC2 interference fragment, resulting in an increased content of RUNX2 mRNA and protein inside BMSCs. Finally, through RNA Immunoprecipitation experiments, we confirmed that YTHDC2 protein can bind to RUNX2 mRNA and accelerate its decomposition. Moreover, the immunofluorescence staining also showed a negative correlation between YTHDC2 and RUNX2. In conclusion, during BMSCs osteogenic differentiation, YTHDC2 protein showed decreased expression, resulting in a higher level of RUNX2 (mRNA and protein) expression inside cells, indicating YTHDC2 as a promising molecular target for the regulation of BMSCs osteogenic differentiation.

Identification of autophagy-associated circRNAs in sepsis-induced cardiomyopathy of mice

Circular RNAs (circRNAs) play a role in sepsis-related autophagy. However, the role of circRNAs in autophagy after sepsis-induced cardiomyopathy (SICM) is unknown, so we explored the circRNA expression profiles associated with autophagy in an acute sepsis mouse model. At a dose of 10 mg/kg, mice were intraperitoneally administered with lipopolysaccharides. The myocardial tissue was harvested after 6 h for microarray analysis, qRT-PCR, and western blotting. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis were evaluated, and a competing endogenous RNA network was constructed, to evaluate the role of circRNAs related to autophagy in SICM. In total, 1,735 differently expressed circRNAs were identified in the LPS-treated group, including 990 upregulated and 745 downregulated circRNAs. The expression level of the autophagy-specific protein p62 decreased, while the ratio of LC3 II to LC3 I increased. Additionally, 309 mRNAs and 187 circRNAs were correlated with autophagy in myocardial tissue after SICM. Of these, 179 circRNAs were predicted to function as "miRNA sponges". Some distinctive circRNAs and mRNAs found by ceRNA analysis might be involved in autophagy in SICM. These findings provide insights into circRNAs and identified new research targets that may be used to further explore the pathogenesis of SICM.

Phytochemical Compounds Involved in the Bone Regeneration Process and Their Innovative Administration: A Systematic Review

Bone metabolism is a complex process which is influenced by the activity of bone cells (e.g., osteocytes, osteoblasts, osteoclasts); the effect of some specific biomarkers (e.g., parathyroid hormone, vitamin D, alkaline phosphatase, osteocalcin, osteopontin, osteoprotegerin, osterix, RANKL, Runx2); and the characteristic signaling pathways (e.g., RANKL/RANK, Wnt/β, Notch, BMP, SMAD). Some phytochemical compounds-such as flavonoids, tannins, polyphenols, anthocyanins, terpenoids, polysaccharides, alkaloids and others-presented a beneficial and stimulating effect in the bone regeneration process due to the pro-estrogenic activity, the antioxidant and the anti-inflammatory effect and modulation of bone signaling pathways. Lately, nanomedicine has emerged as an innovative concept for new treatments in bone-related pathologies envisaged through the incorporation of medicinal substances in nanometric systems for oral or local administration, as well as in nanostructured scaffolds with huge potential in bone tissue engineering.

Biomimetic Porous Magnesium Alloy Scaffolds Promote the Repair of Osteoporotic Bone Defects in Rats through Activating the Wnt/β-Catenin Signaling Pathway

In this study, biomimetic porous magnesium alloy scaffolds were prepared to repair femoral bone defects in ovariectomized osteoporotic rats. The purpose of the study was to investigate the effect of biomimetic porous magnesium alloy scaffolds on repairing osteoporotic bone defects and possible mechanisms. The animal model of osteoporosis was established in female SD rats. Three months later, a bone defect of 3 mm in diameter and 3 mm in depth was created in the lateral condyle of the right femur. The rats were then randomly divided into two groups: an experimental group and a control group. Four weeks after surgery, gross specimens were observed and micro-CT scans were performed. The repair of osteoporotic femoral defects in rats was studied histologically using HE staining, Masson staining, and Goldner staining. The expression of Wnt5a, β-catenin, and BMP-2 was measured between groups by immunohistochemical staining. The bone defect was repaired better after the application of biomimetic porous magnesium alloy scaffolds. Immunohistochemical results showed significantly higher expression of Wnt5a, β-catenin, and BMP-2. To conclude, the biomimetic porous magnesium alloy scaffolds proposed in this paper might promote the repair of osteoporotic femoral bone defects in rats possibly through activating the Wnt/β-catenin signaling pathway.

Anti-aging effects of the pistachio Extract on Mesenchymal Stem Cells proliferation and telomerase activity

PURPOSE

Using mesenchymal stem cells (MSCs) is a promising method in regenerative medicine. Limited proliferation and aging process of MSC are the most common problems in MSCs application. In the present study, we intend to investigate the anti-aging properties of pistachio pericarp in bone marrow-derived MSCs of old male rats.

MATERIALS AND METHODS

First, 1000, 2000, and 3000 µg/mL AEPP were used to treat MSCs derived from bone marrow for 24 h at 37 °C. Then, cell viability, population doubling time, the percentage of senescent cells, telomere length, telomerase activity, and the expression of TRF1 and RAP1 when bone marrow-derived MSCs treated with AEPP were investigated.

RESULTS

The results showed that cell viability increased when MSCs derived from bone marrow were treated with 2000 and 3000 µg/mL AEPP, indicating this extract may stimulate proliferation. The population doubling time was also enhanced with an increase in AEPP concentration. Importantly, an increase in AEPP concentration significantly reduced senescent cell percentage. Telomere length, telomerase activity, and the expression of anti-aging genes were significantly increased with the increase of AEPP dose.

CONCLUSION

Taken together, AEPP has been used as a natural compound with excellent proliferation and anti-aging ability in MSCs. As new therapeutic candidates with promising effects, it can be used with high safety by multiplying cells and delaying the aging process. However, more studies are needed and the anti-aging effects of this extract should be well confirmed in animal models and clinical trials.