Bone-Differentiation-Associated Circ-Spen Regulates Death of Mouse Bone Marrow Mesenchymal Stem Cells by Inhibiting Apoptosis and Promoting Autophagy.

The role of estrogen receptor ß (ERß) in bone health is closely associated with its function in vivo, and ERß-/- mice have been widely utilized to explore the related influences. In this study, ERß-/- female mice were established to investigate the differential expression of circular RNAs (circRNAs) by RNA-Sequencing (RNA-Seq). Among these circRNAs, mmu_circ_0011379 (named Circ-Spen) exhibited high expression in ERß-/- female mice. However, the precise mechanism by which Circ-Spen regulates bone health remained unclear. This study identified Circ-Spen as a positive regulator of mouse bone marrow mesenchymal stem cell (mBMSC) viability. The expression of Circ-Spen was markedly increased in ERß-/- mice femurs tested by RT-qPCR. Moreover, Circ-Spen exhibited an enhanced expression during the bone formation process of mBMSCs. Qualitative experiments also demonstrated that Circ-Spen possessed a circular structure and was localized within the nucleus of mBMSCs. Functionally, it inhibited apoptosis via caspase-3, BCL-2, and BAX, while also promoting autophagy through BECN1 and P62 in mBMSCs tested by MTT assays, transmission electron microscopy (TEM), and Western blotting. These findings reveal the potential of targeting Circ-Spen as a promising therapeutic strategy for rejuvenating senescent mBMSCs and enhancing the efficiency of mBMSC transplantation, which lays the foundation for advancements in the field of bone therapy.

High sodium chloride affects BMP-7 and 1α-hydroxylase levels through NCC and CLC-5 in NRK-52E cells.

A diet high in sodium chloride (NaCl) can affect renal function damage and increase urinary calcium excretion, leading to bone loss. in renal tubules, Na-Cl co-transporter (NCC) and chloride channel 5 (CLC-5) are involved in regulating urinary calcium excretion. In addition, some cytokines, such as Bone morphogenetic protein 7 (BMP-7) and 1α-hydroxylase, are synthesized by renal tubules, which target on bone and play important roles on bone metabolism. However, the specific mechanisms between NaCl and these ion channels or cytokines still need investigations from many aspects. This study, in culture normal rat renal tubular epithelial NRK-52E cells, showed that high concentrations of NaCl significantly inhibited the cell viability and increased the cell apoptosis. High concentration of NaCl reduce bone mineral density (BMD), as demonstrated by the significantly increased mRNA and protein levels of NCC and osteopontin (OPN), but decreased the levels of CLC-5, BMP-7, and 1α-hydroxylase. In addition, we found that ovariectomized (OVX) rats on a high-salt diet for 12 weeks had altered levels of these indices in the renal cortices. Moreover, the BMD in fourth and fifth lumbar vertebra (LV4 and 5) and femurs were significantly decreased and bone microstructure was destroyed of these rats. We also demonstrated that high concentration of NaCl enhanced the inhibition of these cytokines which is beneficial to increase BMD, induced by modulating ion channels NCC and CLC-5. In conclusion, our results indicate that high concentration of NaCl reduce BMD by regulating ion channels NCC and CLC-5.

Effectiveness associated with different therapies for senile osteoporosis: a network Meta-analysis.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of Chinese herbal medicines for invigorating the kidney (CHMIK) on senile osteoporosis. METHODS: We searched for studies in English-language databases (PubMed, the Cochrane Library, and Web of Science) and Chinese-language databases (China National Knowledge Infrastructure, Wan Fang Data, VIP Chinese periodical service platform, and China Biology Medicine disc from their inception to September 2017. Randomized controlled trials comparing the effectiveness of Traditional Chinese Medicine therapies (alone or in combination) and conventional clinical medicine therapies among older adult patients with osteoporosis were identified. We conducted a network Meta-analysis with a Bayesian hierarchical random-effects model using RStudio software, Version 3.4.1. RESULTS: Forty-three randomized controlled trials assessing the differences between Traditional Chinese Medicine and conventional clinical medicine were identified, including 15 treatments and involving 3316 patients. The results of the network Meta-analysis indicated that alendronate (odds ratio [OR] = 0.20, 95% confidence interval [CI]: 0.047-0.73) and calcium (OR = 0.18, 95% CI: 0.11-0.30) are significantly more effective if combined with oral CHMIK. CHMIK alone is significantly more effective than both alendronate (OR = 0.34, 95% CI: 0.10-1.0) and calcium (OR = 0.13, 95% CI: 0.056-0.28). Moreover, CHMIK + tuina + calcium is more effective than CHMIK + calcium + vitamin D + alendronate (OR = 18.0, 95% CI: 1.1-2.7e + 02). CONCLUSION: The present network Meta-analysis found that alendronate and calcium are more effective if combined with oral CHMIK and that oral CHMIK alone may be more effective than alendronate or calcium. Tuina may have an advantage over oral medicines. Oral CHMIK and calcitonin show the most potential for treating senile osteoporosis.

MiR-210-3p inhibits osteogenic differentiation and promotes adipogenic differentiation correlated with Wnt signaling in ERα-deficient rBMSCs.

MicroRNAs (miRNAs) regulate activities in living organisms through various signaling pathways and play important roles in the development and progression of osteoporosis. The balance between osteogenic and adipogenic differentiation of rBMSCs is closely related to the occurrence of osteoporosis. ERα regulates bone metabolism in various tissues. However, the correlation among ERα, miRNAs, and the differentiation of rBMSCs is still unclear. In this study, we used lentivirus transfection into rBMSCs to construct an ERα-deficient model, analyzed the differences in expressed miRNAs between control and ERα-deficient rBMSCs. The results revealed that the expression of 25 miRNAs were upregulated, 164 miRNAs were downregulated, and some of the regulated miRNAs such as miR-210-3p and miR-214-3p were related to osteogenic or adipogenic differentiation, as well as to particular signaling pathways. Next, we overexpressed miR-210-3p to evaluate its effects on the osteogenic and adipogenic differentiation of rBMSCs, and identified the relationship among miR-210-3p, Wnt signaling pathway, and the differentiation of rBMSCs. The results indicated that ERα-deficient inhibited osteogenic differentiation, promoted adipogenic differentiation, and regulated the expression of some miRNAs. Meanwhile, overexpression of miR-210-3p promoted osteogenic differentiation and inhibited adipogenic differentiation of rBMSCs, processes likely to be related to the Wnt signaling pathway. In conclusion, we identified a group of upregulated and downregulated miRNAs in ERα-deficient rBMSCs that might play a vital role in regulating osteogenic or adipogenic differentiation. One of these, miR-210-3p, inhibited osteogenic differentiation and promoted adipogenic differentiation correlated with the Wnt signaling pathway in ERα-deficient rBMSCs, providing new insight into the regulation of bone metabolism.

Icariin stimulates osteogenic differentiation and suppresses adipogenic differentiation of rBMSCs via estrogen receptor signaling.

Icariin (ICA) is a major active ingredient in Herba epimedii, which is commonly used as a Chinese herbal medicine for the treatment of osteoporosis. Previous studies have revealed that ICA exerted a protective effect against bone loss and increased bone regeneration; however, the association between ICA and estrogen receptor (ER) signaling remains unclear. The aim of the present study was to determine the effect of ICA on rat bone marrow stromal cells (rBMSCs). Cell Counting Kit­8 assays were conducted to measure proliferation, alkaline phosphatase (ALP) activity was evaluated to assess osteoblast differentiation, and reverse transcription­quantitative polymerase chain reaction as well as western blotting were performed to detect the expression of cellular and molecular markers of osteogenic or adipogenic differentiation. The results demonstrated that treatment of rBMSCs with 10­6 M ICA stimulated rBMSC proliferation and ALP activity. Furthermore, ICA treatment increased the expression of the osteogenic markers runt­related transcription factor 2, collagen type 1 and bone morphogenetic Protein 2; however, it also decreased the expression of the adipogenic differentiation markers peroxisome proliferator­activated receptor gamma and CCAAT/enhancer­binding protein α. Treatment of rBMSCs with ICI182780, an ER antagonist, blocked the effects of ICA. Taken together, these findings indicated that ICA may stimulate osteoblast differentiation and inhibit adipogenic differentiation via the activation of the ER signaling pathway. Therefore, ICA has the potential to serve as a therapeutic alternative for the prevention and treatment of osteoporosis.

Changes in related circular RNAs following ERß knockdown and the relationship to rBMSC osteogenesis.

Recently, several studies have indicated that circular RNAs (circRNAs) play significant roles in various disease; however, little is known about the chronology of estrogen receptor beta (ERß) deficiency and altered circRNA expression, or their relationship with osteogenesis. Herein, we show through western-blot and quantitative real-time PCR assays, that when ERß is silenced, the expression of osteogenesis-related proteins and mRNAs were down-regulated. We then performed RNA-Seq to analyze differential circRNA expression between the control and ERß knockdown group. This analysis revealed that, 146 circRNAs were differentially expressed by fold-change≥2.0, p ≤ 0.05, and, among this group, 68 circRNAs were down-regulated, while 78 were up-regulated. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and PANTHER pathway analyses were performed to predict the function of these differentially expressed circRNAs. Finally, co-expressed targets gene, and circRNA-microRNA network were constructed for predicted miRNA sponges. This research suggested that ERß may through 2:27713879|27755789/2:240822115|240867796-miR-328-5p-mRNA axis to regulate osteogenic differentiation.