miRNA-187-5p Regulates Osteoblastic Differentiation of Bone Marrow Mesenchymal Stem Cells in Mice by Targeting ICAM1.

Osteoporosis (OP) is a common bone metabolic disease, the process of which is fundamentally irreversible. Therefore, the investigation into osteoblastic differentiation of bone marrow mesenchymal stem cells (BMSCs) will provide more clues for OP treatment. In the present study, we found that microRNA-187-5p (miR-187-5p) played a key role on osteoblastic differentiation, which was significantly upregulated during osteogenic differentiation of BMSCs in mice. Moreover, overexpression of miR-187-5p suppressed osteoblastic differentiation of BMSCs through increasing alkaline phosphatase (ALP), matrix mineralization, and levels of Osterix (OSX), and osteopontin (OPN) as well as runt-related transcription factor 2 (Runx2) in vitro. The results in vivo indicated that the upregulation of miR-187-5p enhanced the efficacy of new bone formation in the heterotopic bone formation assay. Luciferase reporter assay and western blot analysis revealed that miR-187-5p was involved in osteogenesis by targeting intracellular adhesion molecule 1 (ICAM-1). Furthermore, ICAM-1 silence inhibited osteoblastic differentiation of BMSCs. Taken together, our results suggested for the first time that miR-187-5p may promote osteogenesis by targeting ICAM-1, and provided a possible therapeutic target for bone metabolic diseases.

MicroRNA-208a-3p promotes osteosarcoma progression via targeting PTEN.

Osteosarcoma (OS) is a malignant bone tumor with a poor prognosis. Accumulated evidence has suggested that microRNAs (miRNAs/miRs) may function as either oncogenes or tumor suppressors, which are associated with tumorigenesis and the progression of different types of cancer. In the present study, the role of miR-208a-3p in OS was investigated. The expression levels of miR-208a-3p in OS tissues and cell lines were determined via reverse transcription-quantitative PCR (RT-qPCR). MTT and colony formation assays were performed to verify the proliferation rate of OS cells. In addition, the effects of miR-208a-3p on the migration and invasion of OS cells were revealed using wound-healing and Transwell assays, respectively. Furthermore, the association between miR-208a-3p and phosphatase and tensin homolog (PTEN) 3'-untranslated region was determined via luciferase reporter assays, western blot and RT-qPCR analysis. The results indicated that miR-208a-3p was upregulated in OS tissues and cell lines compared with adjacent normal tissues and human osteoblastic cells, respectively. miR-208a-3p overexpression promoted and miR-208a-3p knockdown inhibited OS cells proliferation and metastatic potential. Additionally, PTEN was validated as a direct target of miR-208a-3p and its expression was negatively associate with that of miR-208a-3p in OS cells. Taken together, these results may suggest that miR-208a-3p promoted OS cells proliferation and metastatic potential via targeting PTEN. Therefore, miR-208a-3p may be considered as a diagnostic biomarker for OS.

miR-149-3p Regulates the Switch between Adipogenic and Osteogenic Differentiation of BMSCs by Targeting FTO.

Bone marrow-derived mesenchymal stem cells (BMSCs) have been suggested to possess the capacity to differentiate into different cell lineages. Maintaining a balanced stem cell differentiation program is crucial to the bone microenvironment and bone development. MicroRNAs (miRNAs) have played a critical role in regulating the differentiation of BMSCs into particular lineage. However, the role of miR-149-3p in the adipogenic and osteogenic differentiation of BMSCs has not been extensively discovered. In this study, we aimed to detect the expression levels of miR-149-3p during the differentiation of BMSCs and investigate whether miR-149-3p participated in the lineage choice of BMSCs or not. Compared with mimic-negative control (NC), miR-149-3p mimic decreased the adipogenic differentiation potential of BMSCs and increased the osteogenic differentiation potential. Further analysis revealed that overexpression of miR-149-3p repressed the expression of fat mass and obesity-associated (FTO) gene through binding to the 3' UTR of the FTO mRNA. Also, the role of miR-149-3p mimic in inhibiting adipogenic lineage differentiation and potentiating osteogenic lineage differentiation was mainly through targeting FTO, which also played an important role in regulating body weight and fat mass. In addition, BMSCs treated with miR-149-3p anti-miRNA oligonucleotide (AMO) exhibited higher potential to differentiate into adipocytes and lower tendency to differentiate into osteoblasts compared with BMSCs transfected with NC. In summary, our results detected the effects of miR-149-3p in cell fate specification of BMSCs and revealed that miR-149-3p inhibited the adipogenic differentiation of BMSCs via a miR-149-3p/FTO regulatory axis. This study provided cellular and molecular insights into the observation that miR-149-3p was a prospective candidate gene for BMSC-based bone tissue engineering in treating osteoporosis.

MicroRNA-92b-5p modulates melatonin-mediated osteogenic differentiation of bone marrow mesenchymal stem cells by targeting ICAM-1.

Osteoporosis is closely associated with the dysfunction of bone metabolism, which is caused by the imbalance between new bone formation and bone resorption. Osteogenic differentiation plays a vital role in maintaining the balance of bone microenvironment. The present study investigated whether melatonin participated in the osteogenic commitment of bone marrow mesenchymal stem cells (BMSCs) and further explored its underlying mechanisms. Our data showed that melatonin exhibited the capacity of regulating osteogenic differentiation of BMSCs, which was blocked by its membrane receptor inhibitor luzindole. Further study demonstrated that the expression of miR-92b-5p was up-regulated in BMSCs after administration of melatonin, and transfection of miR-92b-5p accelerated osteogenesis of BMSCs. In contrast, silence of miR-92b-5p inhibited the osteogenesis of BMSCs. The increase in osteoblast differentiation of BMSCs caused by melatonin was attenuated by miR-92b-5p AMO as well. Luciferase reporter assay, real-time qPCR analysis and western blot analysis confirmed that miR-92b-5p was involved in osteogenesis by directly targeting intracellular adhesion molecule-1 (ICAM-1). Melatonin improved the expression of miR-92b-5p, which could regulate the differentiation of BMSCs into osteoblasts by targeting ICAM-1. This study provided novel methods for treating osteoporosis.

Histone deacetylase inhibitor sodium butyrate promotes the osteogenic differentiation of rat adipose-derived stem cells.

Adult stem cells hold great promise for use in tissue repair and regeneration. Recently, adipose tissue-derived stem cells (ADSCs) were found to be an appealing alternative to bone marrow stem cells (BMSCs) for bone tissue engineering. The main benefit of ADSCs is that they can be easily and abundantly available from adipose tissue. However, our prior study discovered an important phenomenon that BMSCs have greater osteogenic potential than ADSCs in vitro and epigenetic regulation plays a critical role in runt-related transcription factor 2 (Runx2) expression and thus osteogenesis. In this study, we aimed to improve the osteogenic potential of ADSCs by histone deacetylase inhibitor sodium butyrate (NaBu). We found that NaBu promoted rat ADSC osteogenic differentiation by altering the epigenetic modifications on the Runx2 promoter.

Catechol-O-methyltransferase (COMT) Val158Met polymorphism and risk of osteoporotic fracture.

Catechol-O-methyltransferase (COMT) is an estrogen degrading enzyme. The COMT Val158Met polymorphism is associated with bone mineral density. The aim of this study was to investigate associations between COMT Val158Met and osteoporotic fractures in Chinese Han patients. Case-control study of 320 patients with osteoporotic fractures and 320 healthy controls were conducted. The COMT Val158Met polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism assay. Patients with osteoporotic fracture had a significantly lower frequency of Val/Val genotype [odds ratio (OR) = 0.62, 95% confidence interval (CI) 0.39-0.99, P = 0.04] than controls. When stratified by the fracture type, there was a significantly lower frequency of Val/Val genotype in patients with vertebral fracture (OR = 0.58, 95% CI 0.36-0.94, P = 0.03) than controls. There was no significant difference in the distribution of each genotype between patients with hip fracture and the control group. Our findings suggest that COMT Val/Val genotype was associated with a lower risk of osteoporotic fracture in Chinese population, especially to vertebral fracture.