Menopause transition promotes distinct modulation of mRNAs and miRNAs expression in calvaria and bone marrow osteoblastic cells

A Perspective on Evaluating Life Stage Differences in Drug Dosages for Drug Labeling and Instructions

Drug labeling and instructions provide essential information for patients regarding the usage of drugs. Instructions for the dosage of drug usage are critical for the effectiveness of the drug and the safety of patients. The dosage of many drugs varies depending on the patient's age. However, as our understanding of human biology deepens, we believe that these instructions need to be modified to incorporate different life stages. This is because human biology and metabolism differ significantly among different life stages, and their responses to drugs also vary. Additionally, the same age of different persons may fall into different life stages. Therefore, our group from multiple institutes and countries proposes a reexamination of whether incorporating life stages in all or any drug instructions will greatly enhance drug efficiency and patients' health.

Identification of miRNAs related to osteoporosis by high-throughput sequencing

Background

Osteoporosis is a major health issue. MicroRNAs (miRNAs) play multiple roles in regulating cell growth and development. High-throughput sequencing technology is widely used nowadays.

Objective

To screen for and validate miRNAs associated with osteoporosis.

Method

Bone specimens from patients with (n = 3) and without (n = 3) osteoporosis were collected. High-throughput sequencing was used to screen for miRNAs that were then analyzed using volcano maps, Wayne maps, gene ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Confirmation of the miRNAs was done using qRT-PCR.

Results

The analysis of sequencing showed that there were 12 miRNAs that were down-regulated and five miRNAs that were upregulated in osteoporosis. GO and KEGG identified these miRNAs as being associated with bone metabolism. The qRT-PCR results showed that miR-140-5p, miR-127-3p, miR-199b-5p, miR-181a-5p, miR-181d-5p, and miR-542-3p exhibited a decrease of 2.27-, 3.00-, 3.48-, 2.67-, 2.41-, and 1.98-fold (all P < 0.05) in osteoporosis compared to controls. Conversely, miR-486-3p and miR-486-5p demonstrated an increase of 2.17- and 3.89-fold (P < 0.05) (all P < 0.05).

Conclusion

This study utilized high-throughput sequencing to detect miRNAs that were expressed differently in individuals with osteoporosis. In osteoporosis, six miRNAs (miR-140-5p, miR-127-3p, miR-199b-5p, miR-181a-5p, miR-181d-5p, and miR-542) were found to have decreased expression, whereas two miRNAs (miR-486-3p and miR-486-5p) were found to have increased expression. The initial manifestation of various miRNAs might serve as predictive indicators and potentially anticipate the progression of osteoporosis.

Lycopene prevents bone loss in ovariectomized rats and increases the number of osteocytes and osteoblasts

Osteoporosis is a prevalent disease with a high incidence in women at the onset of menopause mainly because of hormonal changes, genetics, and lifestyle, leading to decreased bone mass and risk of fractures. Maintaining bone mass is a challenge for postmenopausal women, with calcium-rich food intake being essential for bone health. Nevertheless, other nutrients such as carotenoids may influence bone metabolism because of their high antioxidant properties. This study aimed to evaluate the effect of the carotenoid lycopene on bone cells and in the microarchitecture of ovariectomized rats employing in vitro and in vivo assays. After 8 weeks of ovariectomy, femurs were removed to isolate bone marrow mesenchymal cells to be cultured in osteogenic medium (sham and ovariectomized/OVX) or with 1 μmol/L lycopene (OVX/Lyc). There were performed assays for alkaline phosphatase activity and its in situ detection, mineralization nodules, and quantitative expression of genes associated with osteogenesis. Daily ingestion of 10 mg/kg of lycopene by oral gavage for 8 weeks after ovariectomy was conducted for stereological evaluation of the number and volume of osteoblasts, osteoclasts, and osteocytes of femur distal epiphysis and for microtomographic evaluation of the bone microarchitecture of the femoral proximal epiphysis. Data were normalized and analyzed by comparison among the groups using one-way ANOVA followed by post hoc tests with the significance level set out at 5%. Results showed that lycopene promoted an increase in ALP in situ detection as well as a significant increase in mineralized nodules deposition and expression of genes Runx2 and Bglap when compared with the OVX group. The administration by oral gavage of lycopene increased the total number of osteoblasts and osteocytes when compared to sham and ovariectomized groups. Additionally, it decreased the volume and number of osteoclasts and also reduced the volume of osteocytes compared to the sham group. These results suggest that lycopene improves bone cell metabolism and bone remodeling with the onset of osteoporosis. Future studies with different concentrations and periods of administration should be carried out to shed further light on it.

Investigating miRNA-mRNA interactions and gene regulatory networks from VTA dopaminergic neurons following perinatal nicotine and alcohol exposure using Bayesian network analysis

MicroRNAs play an important role in gene regulation for many biological systems, including nicotine and alcohol addiction. However, the underlying mechanism behind miRNAs and mRNA interaction is not well characterized. Microarrays are commonly used to quantify the expression levels of mRNAs and/or miRNAs simultaneously. In this study, we performed a Bayesian network analysis to identify mRNA and miRNA interactions following perinatal exposure to nicotine and/or alcohol. We utilized three sets of microarray data to predict the regulation relationship between mRNA and miRNAs. Following perinatal alcohol exposure, we identified two miRNAs: miR-542-5p and miR-874-3p, that exhibited a strong mutual influence on several mRNA in gene regulatory pathways, mainly Axon guidance and Dopaminergic synapses. Finally, we confirmed our predicted addiction pathways based on the Bayesian network analysis with the widely used Kyoto Encyclopedia of Genes and Genomes (KEGG)-based database and identified comparable relevant miRNA-mRNA pairs. We believe the Bayesian network can provide insight into the complexity biological process related to addiction and can potentially be applied to other diseases.

Osteoporosis Affects Functional Activity and Gene Expression of Osteoblastic Cells Derived from Rat Alveolar Bone

Recent studies suggest that osteoporosis, in addition to the damage caused in long bones, may cause deterioration in the jaws, especially in alveolar bone sites, with effects in the progress of periodontal disease as well as in bone healing. The aim of this study was to evaluate the effect of osteoporosis in the metabolism of rat alveolar bone osteoblasts. There were used 10 female rats divided in two experimental groups (Sham and OVX), which were ovariectomized and after 8 weeks euthanized to collect mandibular bone samples in order to isolate osteoblastic cells. The cells were cultured in 24-well plates to perform the in vitro experiments. After 7, 10 and 14 days, there were evaluated cell proliferation by MTT assay, in situ detection of alkaline phosphatase (ALP) as well as mineralized nodules and expression of genes associated to bone remodeling. Results showed that at 7, 10 and 14 days cell proliferation was lower for OVX group. In situ detection of ALP was higher at 7 days and lower at 10 and 14 days in OVX group. At 17 and 21 days, OVX group had a significative decrease of mineralization nodules. There was a downregulation in the expression of Alp, Bglap and Runx2 genes and an upregulation of Opg in OVX group, whereas Opn and Rankl modulation was similar between the evaluated groups. Our results suggest that osteoporosis has a deleterious effect on alveolar bone cells from ovariectomized rats, which might affect the treatment of diseases associated to the jaw bones.

Green tea extract rich in epigallocatechin gallate impairs alveolar bone loss in ovariectomized rats with experimental periodontal disease

Periodontal disease and osteoporosis are characterized by bone resorption, and researchers have shown an association between these two diseases through increasing loss of systemic bone mass and triggering alveolar bone loss. Green tea is a common and easily accessible beverage, and evidences show that flavonoid epigallocatechin gallate (EGCG) could decrease bone loss in pathologies such as osteoporosis and periodontal disease. In order to verify its possible effects and apply them in the treatment and prevention of these diseases, this investigation aimed to evaluate the influence of green tea extract (GTE) on bone metabolism of ovariectomized rats after experimental periodontal disease (EPD) by histological, morphological and microtomographic parameters. Wistar female rats were divided into Sham, Sham + EPD, Sham + EPD + GTE, OVX, OVX + EPD and OVX + EPD + GTE groups. Immediately after surgery, gavage administration of 50 mg/kg of green tea extract (GTE) was performed for 60 days, with subsequent induction of periodontal disease by ligature 15 days before euthanasia. Mandible and femur samples were collected for histological, morphometric and microtomographic analysis. The results were analysed by means of statistical software with significance set at 5%. Histological and morphometric analysis showed a significant decrease in alveolar and femoral trabecular bone loss in groups that received GTE. Microtomographic results showed that trabecular thickness and bone surface density values in alveolar bone interradicular septum of the OVX + EPD + GTE groups were similar to the Sham group. The results obtained suggest that green tea extract may improve bone metabolism in osteoporotic rats with periodontal disease.

Lycopene influences osteoblast functional activity and prevents femur bone loss in female rats submitted to an experimental model of osteoporosis

Antioxidant properties of several nutrients may influence bone metabolism, affording protection against damaging effects caused by oxidative stress. Thus, we hypothesized that lycopene may benefit bone tissue metabolism and functional activity of osteoblastic cells from bone marrow of osteoporotic female rats. Wistar rats were ovariectomized and paired with sham animals. In vitro evaluations were performed after 60 days of surgery, when cells were cultured in osteogenic medium and divided in control (C), ovariectomized (OVX) and ovariectomized + 1 μmol/L lycopene (OVXL) groups. Besides, in vivo studies were carried out to evaluate femur bone remodeling by histological and histomorphometric analyses after daily intake of 10 mg/kg of lycopene for 30 and 60 days after ovariectomy. Cell proliferation was significantly higher in OVX and OVXL groups after 10 days of culture. Alkaline phosphatase activity (ALP) was higher in OVXL group in later periods of cell culture, whereas its in situ detection was higher for this group in all experimental periods; nevertheless, mineralization did not show significant differences among the groups. There was a significant upregulation of genes Sp7, Runx2 and Bsp after 3 days and genes Runx2 and Bglap after 10 days from OVXL when compared to OVX. In vivo results demonstrated that daily intake of 10 mg/kg of lycopene for 60 days decreased bone loss in femur epiphysis in ovariectomized rats by maintaining trabecular bone similar to controls. Data obtained suggest that lycopene might benefit the functional activity of osteoblastic cells from ovariectomized rats, as well as avoid further bone resorption.

Identification of novel genes in aging osteoblasts using next-generation sequencing and bioinformatics

During the aging process, impaired osteoblastic function is one key factor of imbalanced bone formation and age-related bone loss. The aim of this study is to explore the differentially expressed genes in normal and aged osteoblasts and to identify genes potentially involved in age-related alteration in bone physiology. Based on next generation sequencing and bioinformatics analysis, 12 differentially expressed microRNAs and 22 differentially expressed genes were identified. Up-regulation of miR-204-5p was validated in an array of osteoporotic hip fracture in the Gene Expression Omnibus database (GSE74209). The putative targets for miR-204-5p were Kruppel-like factor 7 (KLF7) and SRY-box 11 (SOX11). Ingenuity Pathway Analysis identified SOX11, involved in osteoarthritis pathway and differentiation of osteoblasts, together with miR-204-5p, a potential upstream regulator, suggesting the critical role of miR-204-5p-SOX11 regulation in the aging process of human bones. In addition, as semaphorin 3A (SEMA3A) and ephrin type-A receptor 5 (EPHA5) were involved in nervous system related biological functions, we postulated a potential linkage between SEMA3A, EPHA5 and development of neurogenic heterotopic ossification. Our findings implicate new candidate genes in the diagnosis of geriatric musculoskeletal disorders, and provide novel insights that may contribute to the elaboration of new biomarkers for neurogenic heterotopic ossification.