MiRNA-19a-3p alleviates the progression of osteoporosis by targeting HDAC4 to promote the osteogenic differentiation of hMSCs

Roles of Histone Deacetylase 4 in the Inflammatory and Metabolic Processes

Histone deacetylase 4 (HDAC4), a class IIa HDAC, has gained attention as a potential therapeutic target in treating inflammatory and metabolic processes based on its essential role in various biological pathways by deacetylating non-histone proteins, including transcription factors. The activity of HDAC4 is regulated at the transcriptional, post-transcriptional, and post-translational levels. The functions of HDAC4 are tissue-dependent in response to endogenous and exogenous factors and their substrates. In particular, the association of HDAC4 with non-histone targets, including transcription factors, such as myocyte enhancer factor 2, hypoxia-inducible factor, signal transducer and activator of transcription 1, and forkhead box proteins, play a crucial role in regulating inflammatory and metabolic processes. This review summarizes the regulatory modes of HDAC4 activity and its functions in inflammation, insulin signaling and glucose metabolism, and cardiac muscle development.

ECM1-associated miR-1260b promotes osteogenic differentiation by targeting GDI1

Osteoporosis (OP) is a common disease among older adults. The promotion of osteoblast differentiation plays a crucial role in alleviating OP symptoms. Extracellular matrix protein 1 (ECM1) has been reported to be closely associated with osteogenic differentiation. In this study, we constructed U2OS cell lines with ECM1 knockdown and ECM1a overexpression based on knockdown, and identified the target miRNA (miR-1260b) by sequencing. Overexpression of miR-1260b promoted the osteogenic differentiation of U2OS and MG63 cells, as demonstrated by increased alkaline phosphatase (ALP) activity, matrix mineralization, and Runt-Related Transcription Factor 2 (RUNX2), Osteopontin (OPN), Collagen I (COL1A1), and Osteocalcin (OCN) protein expressions, whereas low expression of miR-1260b had the opposite effect. In addition, miR-1260b expression was decreased in OP patients than in non-OP patients. Next, we predicted the target gene of miRNA through TargetScan and miRDB and found that miR-1260b negatively regulated GDP dissociation inhibitor 1 (GDI1) by directly binding to its 3'-untranslated region. Subsequent experiments revealed that GDI1 overexpression decreased ALP activity and calcium deposit, reduced RUNX2, OPN, COL1A1, and OCN expression levels, and reversed the effects of miR-1260b on osteogenic differentiation. In conclusion, ECM1-related miR-1260b promotes osteogenic differentiation by targeting GDI1 in U2OS and MG63 cells. Thus, this study has significant implication for osteoporosis treatment.

Role of non-coding RNAs in osteoporosis

Osteoporosis, a prevalent bone disorder influenced by genetic and environmental elements, significantly increases the likelihood of fractures and bone weakness, greatly affecting the lives of those afflicted. Yet, the exact epigenetic processes behind the onset of osteoporosis are still unclear. Growing research indicates that epigenetic changes could act as vital mediators that connect genetic tendencies and environmental influences, thereby increasing the risk of osteoporosis and bone fractures. Within these epigenetic factors, certain types of RNA, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been recognized as key regulatory elements. These RNA types wield significant influence on gene expression through epigenetic regulation, directing various biological functions essential to bone metabolism. This extensive review compiles current research uncovering the complex ways in which miRNAs, lncRNAs, and circRNAs are involved in the development of osteoporosis, especially in osteoblasts and osteoclasts. Gaining a more profound understanding of the roles these three RNA classes play in osteoporosis could reveal new diagnostic methods and treatment approaches for this incapacitating condition. In conclusion, this review delves into the complex domain of epigenetic regulation via non-coding RNA in osteoporosis. It sheds light on the complex interactions and mechanisms involving miRNAs, lncRNAs, and circRNAs within osteoblasts and osteoclasts, offering an in-depth understanding of the less explored aspects of osteoporosis pathogenesis. These insights not only reveal the complexity of the disease but also offer significant potential for developing new diagnostic methods and targeted treatments. Therefore, this review marks a crucial step in deciphering the elusive complexities of osteoporosis, leading towards improved patient care and enhanced quality of life.

Regulatory mechanism of miR-722 on C5aR1 and its functions against bacterial inflammation in half-smooth tongue sole (Cynoglossus semilaevis)

MicroRNAs (miRNAs) are small non-coding RNAs involved in various biological processes, including immunity. Previously, we investigated the miRNAs of half-smooth tongue sole (Cynoglossus semilaevis) and found that miR-722 (designated Cse-miR-722) was significantly differentially expressed after infection with Vibrio anguillarum, reflecting its importance in immune response. Our preliminary bioinformatic analysis suggested that Cse-miR-722 could target C5aR1 (designated CsC5aR1), which was known to play crucial roles in complement activation and inflammatory response, as a receptor of C5a. However, the underlying mechanisms of their interactions and specific functions in inflammatory and immune response are still enigmas. In this study, we successfully cloned the precursor sequence of Cse-miR-722 (94 bp) and the full length of CsC5aR1 (1541 bp, protein molecular weight 39 kDa). The target gene of Cse-miR-722 was verified as CsC5aR1 by a dual luciferase reporter assay, and Cse-miR-722 was confirmed to regulate CsC5aR1 at the protein level using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. The expression of CsC5aR1 and Cse-miR-722 in liver cells and four immune tissues of half-smooth tongue sole changed significantly after LPS stimulation and infection with V. anguillarum. To explore the functional role of Cse-miR-722 in half-smooth tongue sole, we performed both in vitro and in vivo experiments. Cse-miR-722 was observed to affect phagocytosis and respiratory burst activity of macrophages by regulating CsC5aR1 in half-smooth tongue sole. Furthermore, we found that Cse-miR-722 regulated the expression of CsC5aR1, CsC5a, and the inflammatory factors CsIL1-β, CsIL6, CsIL8, and CsTNF-α both in vitro and in vivo. In addition, Cse-miR-722 reduced mortality and pathological damage. This study clarified the regulatory mechanism of Cse-miR-722 on CsC5aR1 and provided insight into the regulatory roles of Cse-miR-722 in immune responses, laying a theoretical foundation for the feasibility of using miR-722 to prevent and control bacterial diseases in teleost.

Urine-derived stem cells-extracellular vesicles ameliorate diabetic osteoporosis through HDAC4/HIF-1α/VEGFA axis by delivering microRNA-26a-5p

Critical roles of stem cell-extracellular vesicles (EVs) in the management of osteoporosis have been documented. Here, this study was designed to enlarge the research of the specific effects and underlying mechanism of urine-derived stem cells-EVs (USCs-EVs) on osteoporosis in diabetes rats. Firstly, miR-26a-5p and histone deacetylase 4 (HDAC4) expression in USCs of rats after diabetic osteoporosis (DOP) modeling induced by streptozotocin injection was determined, followed by study of their interaction. Then, USCs-EVs were co-cultured with osteogenic precursor cells, the effects of miRNA-26a-5p (miR-26a-5p) on osteoblasts, osteoclasts, bone mineralization deposition rate were evaluated. Meanwhile, the effect of USCs-EVs carrying miR-26a-5p on DOP rats was assessed. Elevated miR-26a-5p was seen in USCs-EVs which limited HDAC4 expression. Moreover, USCs-EVs delivered miR-26a-5p to osteogenic precursor cells, thereby promoting their differentiation, enhancing the activity of osteoblasts, and inhibiting the activity of osteoclasts, thereby preventing DOP through the activation of hypoxia inducible factor 1 subunit alpha (HIF-1α)/vascular endothelial growth factor A (VEGFA) pathway by repressing HDAC4. In a word, USCs-EVs-miR-26a-5p is a promising therapy for DOP by activating HIF-1α/VEGFA pathway through HDAC4 inhibition. 1. USCs-EVs-miR-26a-5p targeted HDAC4 and limited HDAC4 expression. 2. miR-26a-5p was delivered by USCs-EVs into osteoblast precursor cells. 3. USCs-EVs-miR-26a-5p promoted the differentiation of osteoblast precursor cells into osteoblasts. 4. miR-26a-5p delivered by USCs-EVs could inhibit HDAC4. 5. USCs-EVs-miR-26a-5p could prevent the pathogenesis of DOP via HIF-1α/VEGFA aix.

Association between circHIPK3/miR-378a-3p/HDAC4 axis and osteoporotic fractures: A comprehensive investigation

BACKGROUND

Osteoporotic fractures (OFs) are a significant public health issue, which can lead to pain and impaired mobility. The underlying mechanisms of OFs remain unclear, but recent studies have suggested that the circRNA-miRNA-mRNA pathway may play a crucial role.

PURPOSE

This study aimed to investigate the potential involvement of the circHIPK3/miR-378a-3p/HDAC4 pathway in the pathogenesis of OFs.

METHODS

We collected tissue and serum samples from 10 patients with OFs and 10 healthy controls. The expression levels of circHIPK3, miR-378a-3p, and HDAC4 were measured by qPCR and WB. Additionally, we quantified the serum levels of bone metabolism-related indicators (ALP, OC, TRAP, OCIF, ODF) using ELISA.

RESULTS

Our results revealed significant upregulation of circHIPK3 and HDAC4 in both tissue and serum samples from OF patients compared with controls. Simultaneously, we detected a lower expression level of miR-378a-3p in OF tissues and serum than that in the control group. Furthermore, the serum levels of bone metabolism-related indicators ALP, TRAP, OCIF, and ODF were significantly higher in OF patients than in the control group. Interestingly, the serum level of OCIF was lower in OF patients than in the control group.

CONCLUSION

Our study provides important evidence for the involvement of the circHIPK3/miR-378a-3p/HDAC4 pathway in the pathogenesis of OFs. The upregulation of circHIPK3 and HDAC4 and downregulation of miR-378a-3p observed in OF patients suggests their potential regulatory effects on bone metabolism. Meanwhile, abnormal expression of serum bone metabolism-related indicators may contribute to the development of OFs by disrupting the balance of bone remodeling.

Common miRNAs of Osteoporosis and Fibromyalgia: A Review

A significant clinical association between osteoporosis (OP) and fibromyalgia (FM) has been shown in the literature. Given the need for specific biomarkers to improve OP and FM management, common miRNAs might provide promising tracks for future prevention and treatment. The aim of this review is to identify miRNAs described in OP and FM, and dysregulated in the same direction in both pathologies. The PubMed database was searched until June 2023, with a clear mention of OP, FM, and miRNA expression. Clinical trials, case-control, and cross-sectional studies were included. Gray literature was not searched. Out of the 184 miRNAs found in our research, 23 are shared by OP and FM: 7 common miRNAs are dysregulated in the same direction for both pathologies (3 up-, 4 downregulated). The majority of these common miRNAs are involved in the Wnt pathway and the cholinergic system and a possible link has been highlighted. Further studies are needed to explore this relationship. Moreover, the harmonization of technical methods is necessary to confirm miRNAs shared between OP and FM.

MicroRNA-19a-3p Decreases with Age in Mice and Humans and Inhibits Osteoblast Senescence

Aging is a major risk factor for most chronic diseases, including osteoporosis, and is characterized by an accumulation of senescent cells in various tissues. MicroRNAs (miRNAs) are critical regulators of bone aging and cellular senescence. Here, we report that miR-19a-3p decreases with age in bone samples from mice as well as in posterior iliac crest bone biopsies of younger versus older healthy women. miR-19a-3p also decreased in mouse bone marrow stromal cells following induction of senescence using etoposide, H2O2, or serial passaging. To explore the transcriptomic effects of miR-19a-3p, we performed RNA sequencing of mouse calvarial osteoblasts transfected with control or miR-19a-3p mimics and found that miR-19a-3p overexpression significantly altered the expression of various senescence, senescence-associated secretory phenotype-related, and proliferation genes. Specifically, miR-19a-3p overexpression in nonsenescent osteoblasts significantly suppressed p16 Ink4a and p21 Cip1 gene expression and increased their proliferative capacity. Finally, we established a novel senotherapeutic role for this miRNA by treating miR-19a-3p expressing cells with H2O2 to induce senescence. Interestingly, these cells exhibited lower p16 Ink4a and p21 Cip1 expression, increased proliferation-related gene expression, and reduced SA-β-Gal+ cells. Our results thus establish that miR-19a-3p is a senescence-associated miRNA that decreases with age in mouse and human bones and is a potential senotherapeutic target for age-related bone loss. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Circulating and extracellular vesicle-derived microRNAs as biomarkers in bone-related diseases

MicroRNAs (miRNA) are small non-coding RNA molecules that regulate posttranscriptional gene expression by repressing messengerRNA-targets. MiRNAs are abundant in many cell types and are secreted into extracellular fluids, protected from degradation by packaging in extracellular vesicles. These circulating miRNAs are easily accessible, disease-specific and sensitive to small changes, which makes them ideal biomarkers for diagnostic, prognostic, predictive or monitoring purposes. Specific miRNA signatures can be reflective of disease status and development or indicators of poor treatment response. This is especially important in malignant diseases, as the ease of accessibility of circulating miRNAs circumvents the need for invasive tissue biopsy. In osteogenesis, miRNAs can act either osteo-enhancing or osteo-repressing by targeting key transcription factors and signaling pathways. This review highlights the role of circulating and extracellular vesicle-derived miRNAs as biomarkers in bone-related diseases, with a specific focus on osteoporosis and osteosarcoma. To this end, a comprehensive literature search has been performed. The first part of the review discusses the history and biology of miRNAs, followed by a description of different types of biomarkers and an update of the current knowledge of miRNAs as biomarkers in bone related diseases. Finally, limitations of miRNAs biomarker research and future perspectives will be presented.

Circ_0006873 suppresses the osteogenic differentiation of human-derived mesenchymal stem cells through mediating miR-20a/SMURF2 axis in vitro

The clinical application of human-derived mesenchymal stem cells (hMSCs) in osteoporosis (OP) treatment is promising. We aimed to uncover the role of circular RNA 0006873 (circ_0006873) in OP progression using hMSCs. The levels of circ_0006873, pantothenate kinase 2 (PANK2) messenger RNA (mRNA), microRNA-20a (miR-20a), SMAD specific E3 ubiquitin protein ligase 2 (SMURF2) mRNA and the mRNA levels of osteogenesis-related markers were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression of osteogenesis-related markers and SMURF2 was detected by Western blot assay. Alkaline phosphatase (ALP) staining and activity were determined using an ALP staining Kit and an ALP Colorimetric Assay Kit. Circ_0006873 was highly expressed in the serum samples and bone tissue samples of OP patients compared with control cases. Circ_0006873 overexpression down-regulated the expression of osteogenesis-related markers and reduced ALP staining and activity. Circ_0006873 down-regulated miR-20a level through its interaction with miR-20a in hMSCs. Circ_0006873 suppressed osteogenic differentiation through targeting miR-20a. SMURF2 was a molecular target of miR-20a, and miR-20a promoted osteogenic differentiation through targeting SMURF2. Circ_0006873 suppressed the osteogenic differentiation of hMSCs by upregulating SMURF2 level via sponging miR-20a in vitro.

Impact of Environmental and Epigenetic Changes on Mesenchymal Stem Cells during Aging

Many crucial epigenetic changes occur during early skeletal development and throughout life due to aging, disease and are heavily influenced by an individual’s lifestyle. Epigenetics is the study of heritable changes in gene expression as the result of changes in the environment without any mutation in the underlying DNA sequence. The epigenetic profiles of cells are dynamic and mediated by different mechanisms, including histone modifications, non-coding RNA-associated gene silencing and DNA methylation. Given the underlining role of dysfunctional mesenchymal tissues in common age-related skeletal diseases such as osteoporosis and osteoarthritis, investigations into skeletal stem cells or mesenchymal stem cells (MSC) and their functional deregulation during aging has been of great interest and how this is mediated by an evolving epigenetic landscape. The present review describes the recent findings in epigenetic changes of MSCs that effect growth and cell fate determination in the context of aging, diet, exercise and bone-related diseases.

CircRNA hsa_circ_0006859 inhibits the osteogenic differentiation of BMSCs and aggravates osteoporosis by targeting miR-642b-5p/miR-483-3p and upregulating EFNA2/DOCK3

Hsa_circ_0006859 has been found as a possible biomarker for postmenopausal osteoporosis (PMOP) with an effect on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), but the underlying mechanism is unclear. Bioinformatics analysis was used to identify dysregulated RNAs involved in osteoporosis based on public datasets. Function assays were used to determine the functions of hsa_circ_0006859 on cell proliferation and osteogenic differentiation in vitro. It was found that hsa_circ_0006859 was upregulated in OVX mice-derived BMSCs, but lowly expressed during osteogenic differentiation. Overexpressing hsa_circ_0006859 inhibited the cell proliferation and osteogenesis of BMSCs and hFOB 1.19 cells, vice versa. Bilateral ovariectomy (OVX) was used to induce PMOP in mice. The interactions among circ_0006859, miR-642b-5p/miR-483-3p, and EFNA2/DOCK3 were determined using the RIP assay. Silencing circ_0006859 relieved PMOP in mice. Mechanistically, circ_0006859 bound to miR-642b-5p/miR-483-3p directly, while miR-642b-5p and miR-483-3p respectively targeted EFNA2 and DOCK3. Hsa_circ_0006859 downregulated the expression of miR-642b-5p/miR-483-3p to upregulate EFNA2/DOCK3. Additionally, miR-642b-5p/miR-483-3p targeted EFNA2/DOCK3 to inhibit BMSCs osteogenic differentiation and facilitate osteoporosis progression by inactivating the Wnt signaling. In conclusion, hsa_circ_0006859 is involved in PMOP by targeting miR-642b-5p/EFNA2 and miR-483-3p/DOCK3 axes to maintain the Wnt-signaling pathway, which may be a novel possible therapeutic targets and biomarkers for PMOP.

Sharing Circulating Micro-RNAs between Osteoporosis and Sarcopenia: A Systematic Review

Background: Osteosarcopenia, a combination of osteopenia/osteoporosis and sarcopenia, is a common condition among older adults. While numerous studies and meta-analyses have been conducted on osteoporosis biomarkers, biomarker utility in osteosarcopenia still lacks evidence. Here, we carried out a systematic review to explore and analyze the potential clinical of circulating microRNAs (miRs) shared between osteoporosis/osteopenia and sarcopenia. Methods: We performed a systematic review on PubMed, Scopus, and Embase for differentially expressed miRs (p-value < 0.05) in (i) osteoporosis and (ii) sarcopenia. Following screening for title and abstract and deduplication, 83 studies on osteoporosis and 11 on sarcopenia were identified for full-text screening. Full-text screening identified 54 studies on osteoporosis, 4 on sarcopenia, and 1 on both osteoporosis and sarcopenia. Results: A total of 69 miRs were identified for osteoporosis and 14 for sarcopenia. There were 9 shared miRs, with evidence of dysregulation (up- or down-regulation), in both osteoporosis and sarcopenia: miR-23a-3p, miR-29a, miR-93, miR-133a and b, miR-155, miR-206, miR-208, miR-222, and miR-328, with functions and targets implicated in the pathogenesis of osteosarcopenia. However, there was little agreement in the results across studies and insufficient data for miRs in sarcopenia, and only three miRs, miR-155, miR-206, and miR-328, showed the same direction of dysregulation (down-regulation) in both osteoporosis and sarcopenia. Additionally, for most identified miRs there has been no replication by more than one study, and this is particularly true for all miRs analyzed in sarcopenia. The study quality was typically rated intermediate/high risk of bias. The large heterogeneity of the studies made it impossible to perform a meta-analysis. Conclusions: The findings of this review are particularly novel, as miRs have not yet been explored in the context of osteosarcopenia. The dysregulation of miRs identified in this review may provide important clues to better understand the pathogenesis of osteosarcopenia, while also laying the foundations for further studies to lead to effective screening, monitoring, or treatment strategies.

Regulatory mechanisms of microRNAs in endocrine disorders and their therapeutic potential

MicroRNAs (miRNAs) are small endogenous non-coding RNA molecules capable of regulating gene expression at the post-transcriptional level either by translational inhibition or mRNA degradation and have recently been importantly related to the diagnosis and prognosis of the most relevant endocrine disorders. The endocrine system comprises various highly vascularized ductless organs regulating metabolism, growth and development, and sexual function. Endocrine disorders constitute the fifth principal cause of death worldwide, and they are considered a significant public health problem due to their long-term effects and negative impact on the patient's quality of life. Over the last few years, miRNAs have been discovered to regulate various biological processes associated with endocrine disorders, which could be advantageous in developing new diagnostic and therapeutic tools. The present review aims to provide an overview of the most recent and significant information regarding the regulatory mechanism of miRNAs during the development of the most relevant endocrine disorders, including diabetes mellitus, thyroid diseases, osteoporosis, pituitary tumors, Cushing's syndrome, adrenal insufficiency and multiple endocrine neoplasia, and their potential implications as disease biomarkers.

Epigenetic control of mesenchymal stem cells orchestrates bone regeneration

Recent studies have revealed the vital role of MSCs in bone regeneration. In both self-healing bone regeneration processes and biomaterial-induced healing of bone defects beyond the critical size, MSCs show several functions, including osteogenic differentiation and thus providing seed cells. However, adverse factors such as drug intake and body senescence can significantly affect the functions of MSCs in bone regeneration. Currently, several modalities have been developed to regulate MSCs' phenotype and promote the bone regeneration process. Epigenetic regulation has received much attention because of its heritable nature. Indeed, epigenetic regulation of MSCs is involved in the pathogenesis of a variety of disorders of bone metabolism. Moreover, studies using epigenetic regulation to treat diseases are also being reported. At the same time, the effects of epigenetic regulation on MSCs are yet to be fully understood. This review focuses on recent advances in the effects of epigenetic regulation on osteogenic differentiation, proliferation, and cellular senescence in MSCs. We intend to illustrate how epigenetic regulation of MSCs orchestrates the process of bone regeneration.

Positive programming of the GC-IGF1 axis mediates adult osteoporosis susceptibility in male offspring rats induced by prenatal dexamethasone exposure

Prenatal dexamethasone exposure (PDE) can lead to offspring long bone dysplasia and continue to postnatal, and this is an important cause of fetal-derived osteoporosis. Studies have confirmed that intrauterine endogenous GC overexposure mediates multiple organ dysplasia and adult-related disease susceptibility in offspring through the glucocorticoid-insulin-like growth factor1 (GC-IGF1) axis. However, it remains unknown if exogenous dexamethasone can regulate bone development in offspring through the GC-IGF1 axis. We determined that the PDE fetal rats exhibited poor osteogenic differentiation, decreased bone mass that continued to adolescence, and increased susceptibility to osteoporosis in adulthood. Concurrently, PDE decreased the serum corticosterone concentration and IGF1 expression in offspring before and after birth, while the increased serum corticosterone concentration induced by chronic stress reversed the inhibition of IGF1 expression induced by PDE. Furthermore, PDE decreased the expression of GRα and miR-130a-5p, increased HDAC4, and decreased H3K27 acetylation in the IGF1 promoter region in bone tissue, and the above changes were negatively compensated after chronic stress. In vitro, a low concentration of corticosterone inhibited the expression of GRα and miR130a-5p, upregulated the expression of HDAC4, inhibited the promoter region H3K27 acetylation, and expression of IGF1 in bone marrow mesenchymal stem cell (BMSCs) osteoblast differentiated cells and inhibited osteogenic differentiation of BMSCs. GRα overexpression, miR-130a-5p mimic treatment, or HDAC4 siRNA exposure reversed the downstream molecular alterations caused by low corticosterone concentrations. In conclusion, PDE-induced intrauterine hypoglucocorticoid exposure could positively program IGF1 expression in bone tissue through the GRα/miR-130a-5p/HDAC4 pathways, thus mediating osteogenic dysdifferentiation and adult osteoporosis susceptibility in male offspring rats.

Neuroprotection of Bone Marrow-Derived Mesenchymal Stem Cell-Derived Extracellular Vesicle-Enclosed miR-410 Correlates with HDAC4 Knockdown in Hypoxic-Ischemic Brain Damage

Evidence exists reporting that miR-410 may rescue neurological deficits, neuronal injury, and neuronal apoptosis after experimental hypoxic ischemia. This study aimed to explore the mechanism by which miR-410 transferred by bone marrow-derived mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) may alleviate hypoxic-ischemic brain damage (HIBD) in newborn mice. BMSCs were isolated from total bone marrow cells of femur and tibia of newborn mice, and primary neurons were extracted from the cerebral cortex of newborn mice within 24 h of birth. EVs were extracted from BMSCs transfected with the mimic or inhibitor of miR-410. Primary neurons were subjected to hypoxia and treated with overexpression (oe)-HDAC4, small interfering RNA (siRNA)-β-catenin, or Wnt pathway inhibitor and/or EV (miR-410 mimic) or EV (miR-410 inhibitor). A neonatal mouse HIBD model was established and treated with EVs. When BMSC-EVs were endocytosed by primary neurons, miR-410 was upregulated, neuronal viability was elevated, and apoptosis was inhibited. miR-410 in BMSC-EVs targeted HDAC4, thus increasing neuronal viability and reducing apoptosis. Conversely, overexpression of HDAC4 activated the Wnt pathway and enhanced the nuclear translocation of β-catenin. Treatment with miR-410-containing BMSC-EVs improved learning and memory abilities of HIBD mice while attenuating apoptosis by inactivating the Wnt pathway via targeting HDAC4. Taken together, the findings suggest that miR-410 delivered by BMSC-EVs alleviates HIBD by inhibiting HDAC4-dependent Wnt pathway activation.

Comprehensive analysis of lncRNA expression profiles in postmenopausal osteoporosis

To explore the key lncRNAs affecting postmenopausal osteoporosis (PMOP) progression, the transcriptome sequencing of peripheral blood mononuclear cells from fifteen early postmenopausal women, according to bone mineral density, were divided into groups of osteoporosis, osteopenia and normality, in each of which the expression profiles of lncRNAs was investigated. From the results we observed nine candidates of lncRNAs, which were to be compared with miRBase, and found that MIR22HG as one candidate of lncRNA was most likely to be directly used as miRNA precursor. Based on the KEGG annotation and lncRNA-miRNA-mRNA-KEGG network, we analyzed the potential role of candidate lncRNAs. The results showed that the expression profiles of lncRNAs could help identify the novel ones involved in the progression of PMOP, and that MIR22HG could serve as a miRNA precursor to regulate FoxO signaling pathway in bone metabolism. Our findings can be of great help in predicting and diagnosing early PMOP.

Epigenetic regulation in cardiovascular disease: mechanisms and advances in clinical trials

Epigenetics is closely related to cardiovascular diseases. Genome-wide linkage and association analyses and candidate gene approaches illustrate the multigenic complexity of cardiovascular disease. Several epigenetic mechanisms, such as DNA methylation, histone modification, and noncoding RNA, which are of importance for cardiovascular disease development and regression. Targeting epigenetic key enzymes, especially the DNA methyltransferases, histone methyltransferases, histone acetylases, histone deacetylases and their regulated target genes, could represent an attractive new route for the diagnosis and treatment of cardiovascular diseases. Herein, we summarize the knowledge on epigenetic history and essential regulatory mechanisms in cardiovascular diseases. Furthermore, we discuss the preclinical studies and drugs that are targeted these epigenetic key enzymes for cardiovascular diseases therapy. Finally, we conclude the clinical trials that are going to target some of these processes.

MicroRNA-577 aggravates bone loss and bone remodeling by targeting thyroid stimulating hormone receptor in hyperthyroid-associated osteoporosis

Traditionally, hyperthyroid-associated osteoporosis has been considered to be the result of increased thyroid hormone levels. The pathogenesis of hyperthyroid-associated osteoporosis remains unclear. Thyroid stimulating hormone receptor (TSHR) is closely associated with osteoporosis. Our study aimed to explore the role of TSHR and its upstream microRNA (miRNA) in hyperthyroid-associated osteoporosis. Bioinformatics analysis (starBase and Targetscan) and a wide range of experiments including reverse-transcription quantitative polymerase chain reaction, luciferase reporter, western blot analysis of osteogenic differentiation markers including OSX, OCN, ALP, OPN, and COL1, hematoxylin and eosin staining, Alizarin Red staining assays were used to explore the function and mechanism of TSHR in hyperthyroid-associated osteoporosis. First, we observed that TSHR was downregulated in bone marrow mesenchymal stem cells (BMSCs) isolated from rats after culture in osteogenic medium for 7 days. Functionally, overexpression of TSHR accelerates BMSC osteogenic differentiation. Mechanistically, we predicted four potential miRNAs for TSHR. MiR-577 was validated to bind with TSHR. Rescue assays showed that miR-577 overexpression inhibited BMSC osteogenic differentiation via targeting TSHR. In vivo experiments showed that miR-577 aggravated bone loss and bone remodeling and our data showed that it is achieved by targeting TSHR in hyperthyroid-associated osteoporosis. This finding may deep our understanding of the pathogenesis of hyperthyroid-associated osteoporosis.

microRNA-211-5p predicts the progression of postmenopausal osteoporosis and attenuates osteogenesis by targeting dual specific phosphatase 6

Postmenopausal osteoporosis (PMOP) is known as one of the prevalent diseases among middle-aged and elderly women. This paper revolves around the alteration of miR-211-5p in PMOP patients and its function in osteogenic differentiation. Quantitative real-time polymerase chain reaction (qRT-PCR) was implemented to check the miR-211-5p level in the plasma of PMOP patients. Knockdown and overexpression experiments were done to verify the influence of miR-211-5p on human-derived mesenchymal stem cell (hMSC) osteogenic differentiation and osteogenesis. The alkaline phosphatase (ALP) assay kit was taken to test ALP activity. Alizarin red staining monitored osteogenic differentiation, while oil red O staining examined adipogenesis. Western blot confirmed the profiles of osteoclastogenesis-concerned factors (TRAP, NFAT2, c-FOS, Runx2, OCN, CTSK), dual specific phosphatase 6 (DUSP6), ERK, SMAD, and β-catenin. Dual-luciferase reporter and RNA immunoprecipitation assays were implemented to identify the association between miR-211-5p and DUSP6. Our data displayed that miR-211-5p was down-regulated in the PMOP patients’ plasma (in contrast with the healthy controls), and it was positively correlated with Vit-D and BMD levels. miR-211-5p overexpression vigorously facilitated hMSC osteogenic differentiation, while miR-211-5p inhibition contributed to the opposite situation. miR-211-5p initiated the ERK/SMAD/β-catenin pathway and repressed DUSP6’s expression. Overexpression of DUSP6 counteracted the miR-211-5p-mediated function to a great extent and inactivated ERK/SMAD/β-catenin, whereas enhancing ERK phosphorylation weakened the DUSP6 overexpression-induced function. Consequently, this research unveiled that miR-211-5p promotes osteogenic differentiation by interfering with the DUSP6-mediated ERK/SMAD/β-catenin pathway.

Identification of circRNA Expression Profiles in BMSCs from Glucocorticoid-Induced Osteoporosis Model

Background. Circular RNAs (circRNAs) contribute to the regulation of many diseases. However, little is known about the role of circRNAs in the development of glucocorticoid-induced osteoporosis (GIOP). The present study is aimed at systematically characterizing the circRNA expression profiles in GIOP and predict the potential functions of the associated regulatory networks. Methods. A small animal GIOP model was developed in Sprague-Dawley rats given daily intraperitoneal doses of the synthetic glucocorticoid dexamethasone. Micro-CT and bone histomorphometry were performed to characterize the bone loss. Alizarin red S (ARS) staining and alkaline phosphatase (ALP) activity were assessed to determine the osteogenic differentiation potential of BMSCs. RNA sequencing was performed to identify differentially expressed circRNAs in BMSCs between the GIOP and normal groups, which were validated by qRT-PCR. siRNA interference experiments were used to demonstrate their function. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict the functions of differentially expressed circRNAs. The microRNA (miRNA) targets of the circRNAs and circRNA-miRNA interactions were predicted. Results. Micro-CT and bone histomorphometry confirmed the rat GIOP model. Both ARS intensity and ALP activity were decreased in GIOP BMSCs. Seventeen circRNAs were identified by $\text{fold}\text{change}=2.0$ , $p<0.05$ , and $\text{false}\text{discovery}\text{rate}<0.05$ , of which 7 were upregulated and 10 were downregulated. The qRT-PCR results of the selected circRNAs were consistent with the RNA-seq results and showed that circARSB and circAKT3 were significantly upregulated, while circPTEN and circTRPM7 were downregulated in the GIOP group. Further functional experiments found that downregulation of circARSB and circPTEN expression resulted in a corresponding change in osteogenic differentiation, suggesting that circARSB negatively, while circPTEN positively, regulates BMSC osteogenic differentiation. Analysis of circRNA-targeted miRNAs predicted that miR-135a-5p was associated with circARSB and circAKT3, and miR-881-3p was associated with circPTEN and circTRPM7. Furthermore, the signalling pathways associated with these differentially expressed circRNAs were predicted. Conclusions. The present study identified circARSB, circAKT3, circPTEN, and circTRPM7 as being associated with osteogenic differentiation during GIOP through a circRNA-targeted miRNA-mRNA axis, which might provide insight into the pathophysiological mechanism of GIOP.

miR-27b attenuates dexamethasone-inhibited proliferation and osteoblastic differentiation in MC3T3-E1 cells by targeting PPARγ2

Osteoporosis is a metabolic bone illness characterized by low bone density and a high risk of fracture. It is estimated that there are >60 million individuals in China suffering from this disease, which highlights an urgent requirement for the development of novel and safe drugs for the long-term treatment of osteoporosis. MicroRNAs (miRNAs/miRs) have previously been identified as critical regulators in the progression of osteoporosis. As an intronic miRNA, miR-27b enhances the osteoblastic differentiation of stem cells from the bone marrow and the maxillary sinus membrane. However, the mechanism underlying miR-27b in osteoporosis remains to be elucidated. In the present study, MC3T3-E1 pre-osteoblasts were treated with dexamethasone (DEX) to establish an in vitro model of osteoporosis. The results of the present study demonstrated that DEX treatment markedly inhibited the viability of MC3T3-E1 cells, and downregulated the expression level of miR-27b. The results of reverse transcription-quantitative PCR, western blotting and dual-luciferase assays revealed that miR-27b directly regulated and suppressed the expression of peroxisome proliferator-activated receptor γ2 (PPARγ2) in MC3T3-E1 cells. Furthermore, overexpression of miR-27b by transfection of cells with miR-27b mimic attenuated DEX-mediated inhibition of cell viability, alkaline phosphatase (ALP) activity and the expression levels of bone morphogenetic protein-2 (BMP2), runt-related protein 2 (Runx2) and osteocalcin (OCN). The results of the present study indicated that miR-27b alleviated DEX-inhibited proliferation and osteoblastic differentiation. Moreover, miR-27b knockdown repressed MC3T3-E1 cell viability, ALP activity and protein levels of BMP2, Runx2 and OCN. However, these effects were abrogated by small interfering RNA-mediated PPARγ2 silencing. In conclusion, the results of the present study demonstrated that miR-27b attenuated DEX-inhibited proliferation and osteoblastic differentiation in MC3T3-E1 pre-osteoblasts by targeting PPARγ2.

Down-regulation of miR-340-5p promoted osteogenic differentiation through regulation of runt-related transcription factor-2 (RUNX2) in MC3T3-E1 cells

Diabetic osteoporosis (DOP) is a chronic complication of diabetes in the skeletal system. High level of miR-340-5p may be harmful to the bone formation. In this study, the DOP model of rats was successfully established via streptozotocin (STZ) and ovariectomy (OVX) treatment. It was manifested by reduced body weight, insulin level, alkaline phosphatase (ALP) activity, and osteocalcin (OCN) and collagen-I expressions, as well as increased concentration of fasting blood glucose. Moreover, we found that miR-340-5p expression was increased while runt-related transcription factor-2 (RUNX2) was decreased in femurs. Furthermore, the effects of miR-340-5p on osteogenic differentiation (OD) in high glucose (HG)-treated MC3T3-E1 cells were explored. Exposure to OD and HG contributed to elevated miR-340-5p level. Inhibition of miR-340-5p enhanced ALP level, calcium deposition, and OCN, collagen-I and RUNX2 levels. On the contrary, miR-340-5p overexpression reversed these promotional effects. Luciferase assay indicated that RUNX2 may be a target gene of miR-340-5p. Moreover, RUNX2 deficiency decreased miR-340-5p inhibition-induced ALP activity, calcium accumulation and OCN, collagen-I, RUNX2 levels. In short, the above findings revealed that inhibition of miR-340-5p facilitated osteogenic differentiation through regulating RUNX2 in MC3TC-E1 cells, which provided targeted therapeutic strategies for the treatment of DOP.

USF2 reduces BMP3 expression via transcriptional activation of miR-34a, thus promoting osteogenic differentiation of BMSCs

INTRODUCTION

Osteoporosis is the most susceptible disease for people over 60. The main cause of osteoporosis is the decreased osteogenic differentiation of mesenchymal stem cells (MSCs). Here we showed that upstream stimulatory factor 2 (USF2)/microRNA-34a (miR-34a)/bone morphogenetic protein 3 (BMP3) axis regulated osteogenic differentiation of BMSCs.

MATERIALS AND METHODS

USF2 and miR-34a expression were examined using qPCR. Protein levels of BMP3 and osteogenic markers expression were evaluated using both western blot and qPCR. Activity of ALP was determined by ALP assay kit. Mineralization capacity of hBMSCs was assessed using ARS. Besides, CHIP assay was employed to verify whether USF2 could bind to miR-34a promoter. Finally, RIP assay and dual-luciferase reporter assay were employed to verify whether miR-34a directly bound to BMP3.

RESULTS

Our results suggested that miR-34a was upregulated during osteogenic differentiation of BMSCs, and miR-34a overexpression could enhance osteogenic differentiation of BMSCs. USF2 could positively regulate miR-34a expression by interacting with its promoter. USF2 overexpression enhanced osteogenic differentiation of BMSCs, while miR-34a inhibition reversed the effect. Besides, BMP3 was the target of miR-34a. MiR-34a overexpression enhanced osteogenic differentiation of BMSCs, which was abolished by BMP3 overexpression.

CONCLUSION

Taken together, USF2 enhanced osteogenic differentiation of BMSCs via downregulating BMP3 by interacting with miR-34a promoter.

The Role of miR-34c-5p in Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells

Background and Objectives

Osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) plays a critical role in the success of lumbar spinal fusion with autogenous bone graft. This study aims to explore the role and specific mechanism of miR-34c-5p in osteogenic differentiation of BMSCs.

Methods and Results

Rabbit model of lumbar fusion was established by surgery. The osteogenic differentiation dataset of mesenchymal stem cells was obtained from the Gene Expression Omnibus (GEO) database, and differentially expressed miRNAs were analyzed using R language (limma package). The expressions of miR-34c-5p, miR-199a-5p, miR-324-5p, miR-361-5p, RUNX2, OCN and Bcl-2 were determined by qRT-PCR and Western blot. ELISA, Alizarin red staining and CCK-8 were used to detect the ALP content, calcium deposition and proliferation of BMSCs. The targeted binding sites between miR-34c-5p and Bcl-2 were predicted by the Target database and verified using dual-luciferase reporter assay. MiR-34c-5p expression was higher in rabbit lumbar fusion model and differentiated BMSCs than normal rabbit or BMSCs. The content of ALP and the deposition of calcium increased with the osteogenic differentiation of BMSCs. Upregulation of miR-34c-5p reduced cell proliferation and promoted ALP content, calcium deposition, RUNX2 and OCN expression compared with the control group. The effects of miR-34c-5p inhibitor were the opposite. In addition, miR-34c-5p negatively correlated with Bcl-2. Upregulation of Bcl-2 reversed the effects of miR-34c-5p on ALP content, calcium deposition, and the expressions of RUNX2 and OCN.

Conclusions

miR-34c-5p could promote osteogenic differentiation and suppress proliferation of BMSCs by inhibiting Bcl-2.

Next‑generation sequencing of miRNAs and lncRNAs from rat femur and tibia under mechanical stress

Exercise intervention has become one of the most effective methods to prevent and treat osteoporosis, which is a common age‑related disease and seriously affects the health and quality of life of the elderly. However, the molecular mechanism remains to be elucidated. The present study demonstrated the exercise‑induced promotion of osteogenic differentiation and inhibition of adipogenic differentiation in femur and tibia by establishing an animal exercise model using a treadmill exercise system. MicroRNA (miRNA/miR) and long non‑coding (lnc)RNA sequencing analyses identified 16 upregulated and two downregulated miRNAs in the exercise group, as well as 44 upregulated lncRNAs and 39 downregulated lncRNAs in the exercise group. There was increased expression of miR‑9942 and miR‑7704 in both the femur and tibia and an upregulation of miR‑30d, miR‑5100 and miR‑1260 in the femur of animals from the exercise group. In addition, four of the five most downregulated lncRNAs, including lncRNA MSTRG.2625, lncRNA MSTRG.1557, lncRNA MSTRG.691 and lncRNA MSTRG.7497, were demonstrated to be suppressed in both the femur and tibia after treadmill exercise. The results of the present study provided a valuable resource for further exploring the molecular mechanisms underlying the regulation of osteoporosis by exercise.

Contribution of miRNAs and lncRNAs in osteogenesis and related disorders

Non-coding RNAs have been found to regulate several developmental processes among them is osteogenesis. Although these transcripts have several distinct classes, two classes i.e. microRNAs and long non-coding RNAs have attained more attention. These transcripts regulate intramembranous as well as endochondral ossification processes. The effects of microRNAs on osteogenesis are mostly mediated through modulation of Wnt/β-catenin and TGFβ/BMP pathways. Long non-coding RNAs can directly affect expression of these pathways or osteogenic transcription factors. Moreover, they can serve as a molecular sponge for miRNAs. MALAT1/miR-30, MALAt1/miR-214, LEF1-AS1/miR-24-3p, MCF2L-AS1/miR-33a, MSC-AS1/miR-140-5p and KCNQ1OT1/miR-214 are examples of such kind of interaction between lncRNAs and miRNAs in the context of osteogenesis. In the current paper, we explain these two classes of non-coding RNAs in the osteogenesis and related disorders.

Application of microRNA in Human Osteoporosis and Fragility Fracture: A Systemic Review of Literatures

MicroRNAs (miRNAs) could serve as ideal entry points to the deregulated pathways in osteoporosis due to their relatively simple upstream and downstream relationships with other molecules in the signaling cascades. Our study aimed to give a comprehensive review of the already identified miRNAs in osteoporosis from human blood samples and provide useful information for their clinical application. A systematic literature search for relevant studies was conducted in the Pubmed database from inception to December 2020. We set two essential inclusion criteria: human blood sampling and design of controlled studies. We sorted the results of analysis on human blood samples according to the study settings and compiled the most promising miRNAs with analyzed diagnostic values. Furthermore, in vitro and in vivo evidence for the mechanisms of the identified miRNAs was also illustrated. Based on both diagnostic value and evidence of mechanism from in vitro and in vivo experiments, miR-23b-3p, miR-140-3p, miR-300, miR-155-5p, miR-208a-3p, and miR-637 were preferred candidates in diagnostic panels and as therapeutic agents. Further studies are needed to build sound foundations for the clinical usage of miRNAs in osteoporosis.

Skeletal Aging and Osteoporosis: Mechanisms and Therapeutics

Bone is a dynamic organ maintained by tightly regulated mechanisms. With old age, bone homeostasis, which is maintained by an intricate balance between bone formation and bone resorption, undergoes deregulation. Oxidative stress-induced DNA damage, cellular apoptosis, and cellular senescence are all responsible for this tissue dysfunction and the imbalance in the bone homeostasis. These cellular mechanisms have become a target for therapeutics to treat age-related osteoporosis. Genetic mouse models have shown the importance of senescent cell clearance in alleviating age-related osteoporosis. Furthermore, we and others have shown that targeting cellular senescence pharmacologically was an effective tool to alleviate age- and radiation-induced osteoporosis. Senescent cells also have an altered secretome known as the senescence associated secretory phenotype (SASP), which may have autocrine, paracrine, or endocrine function. The current review discusses the current and potential pathways which lead to a senescence profile in an aged skeleton and how bone homeostasis is affected during age-related osteoporosis. The review has also discussed existing therapeutics for the treatment of osteoporosis and rationalizes for novel therapeutic options based on cellular senescence and the SASP as an underlying pathogenesis of an aging bone.

The role of microRNAs in bone development

Epigenetic regulation is critical for proper bone development. Evidence from a large body of published literature informs us that microRNAs (miRNAs) are important epigenetic factors that control many aspects of bone development, homeostasis, and repair processes. These small non-coding RNAs function at the post-transcriptional level to suppress expression of specific target genes. Many target genes may be affected by one miRNA resulting in alteration in cellular pathways and networks. Therefore, changes in levels or activity of a specific miRNA (e.g. via genetic mutations, disease scenarios, or by over-expression or inhibition strategies in vitro or in vivo) can lead to substantial changes in cell processes including proliferation, metabolism, apoptosis and differentiation. In this review, Section 1 briefly covers general background information on processes that control bone development as well as the biogenesis and function of miRNAs. In Section 2, we discuss the importance of miRNAs in skeletal development based on findings from in vivo mouse models and human clinical reports. Section 3 focuses on describing more recent data from the last three years related to miRNA regulation of osteoblast differentiation in vitro. Some of these studies also involve utilization of an in vivo rodent model to study the effects of miRNA modulation in scenarios of osteoporosis, bone repair or ectopic bone formation. In Section 4, we provide some recent information from studies analyzing the potential of miRNA-mediated crosstalk in bone and how exosomes containing miRNAs from one bone cell may affect the differentiation or function of another bone cell type. We then conclude by summarizing where the field currently stands with respect to miRNA-mediated regulation of osteogenesis and how information gained from developmental processes can be instructive in identifying potential therapeutic miRNA targets for the treatment of certain bone conditions.

MiR-206 regulates the progression of osteoporosis via targeting HDAC4

Background

More and more studies have confirmed that miRNAs play an important role in maintaining bone remodeling and bone metabolism. This study investigated the expression level of miR-206 in the serum of osteoporosis (OP) patients and explored the effect and mechanism of miR-206 on the occurrence and development of osteoporosis.

Methods

120 postmenopausal women were recruited, including 63 cases with OP and 57 women without OP. The levels of miR-206 were determined by qRT-PCR technology. Spearman correlation coefficient was used to evaluate the correlation of miR-206 with bone mineral density (BMD). An ROC curve was used to evaluate the diagnostic value of miR-206 in osteoporosis. The effects of miR-206 on cell proliferation and cell apoptosis of hFOBs were measured by CCK-8 assay and flow cytometry, respectively. Luciferase reporter gene assay was used to confirm the interaction of miR-206 and the 3′UTR of HDAC4.

Results

Serum miR-206 had low expression level in osteoporosis patient group compared with control group. The expression level of serum miR-206 had diagnostic value for osteoporosis, and the serum miR-206 levels were positively correlated with BMD. The down-regulated miR-206 could inhibit cell proliferation and promote cell apoptosis. Luciferase analysis indicated that HDAC4 was the target gene of miR-206.

Conclusions

MiR-206 could be used as a new potential diagnostic biomarker for osteoporosis, and in in vitro cell experiments, miR-206 may regulate osteoblast cell proliferation and apoptosis by targeting HDAC4.

Kaempferol promotes BMSC osteogenic differentiation and improves osteoporosis by downregulating miR-10a-3p and upregulating CXCL12

BACKGROUND

Kaempferol has improved the functions of various human diseases. Here, we aimed to probe into the potential molecular mechanism of Kaempferol to ameliorate osteoporosis.

METHODS

Micro-computed tomography scanning was applied to assess the bone density of osteoporosis rats induced by ovariectomized. Quantitative real-time PCR was applied to detect the expressions of RUNX2, Osterix, CXCL12, and miR-10a-3p. Western blot, Alizarin red staining, Alkaline Phosphatase Diethanolamine Activity Kit were applied to confirm the in vitro functions of Kaempferol. RNA Immunoprecipitation and dual-luciferase reporter gene experiments were applied to study the potential mechanism.

RESULTS

The treatment of Kaempferol raised bone density in osteoporosis rats induced by ovariectomized, and boosted the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and raised the expressions of RUNX2, Osterix, and CXCL12, and lessened miR-10a-3p. From the potential mechanism analysis, we corroborated that miR-10a-3p and CXCL12 bound to each other, and Kaempferol boosted BMSC osteogenic differentiation and ameliorated osteoporosis by lessening miR-10a-3p and raising CXCL12.

CONCLUSION

Our data expounded that Kaempferol boosted BMSC osteogenic differentiation and ameliorated osteoporosis by lessening miR-10a-3p and raising CXCL12.

miRNA Mechanisms Underlying the Association of Beta Blocker Use and Bone Mineral Density

Osteoporosis is a debilitating and costly disease that causes fractures in 33% of women and 20% of men over the age of 50 years. Recent studies have shown that beta blocker (BB) users have higher bone mineral density (BMD) and decreased risk of fracture compared with non-users. The mechanism underlying this association is thought to be due to suppression of adrenergic signaling in osteoblasts, which leads to increased BMD in rodent models; however, the mechanism in humans is unknown. Also, several miRNAs are associated with adrenergic signaling and BMD in separate studies. To investigate potential miRNA mechanisms, we performed a cross-sectional analysis using clinical data, dual-energy X-ray absorptiometry (DXA) scans, and miRNA and mRNA profiling of whole blood from the Framingham Study's Offspring Cohort. We found nine miRNAs associated with BB use and increased BMD. In parallel network analyses, we discovered a subnetwork associated with BMD and BB use containing two of these nine miRNAs, miR-19a-3p and miR-186-5p. To strengthen this finding, we showed that these two miRNAs had significantly higher expression in individuals without incident fracture compared with those with fracture in an external data set. We also noted a similar trend in association between these miRNA and Z-score as calculated from heel ultrasound measures in two external cohorts (SOS-Hip and SHIP-TREND). Because miR-19a directly targets the ADRB1 mRNA transcript, we propose BB use may downregulate ADRB1 expression in osteoblasts through increased miR-19a-3p expression. We used enrichment analysis of miRNA targets to find potential indirect effects through insulin and parathyroid hormone signaling. This analysis provides a starting point for delineating the role of miRNA on the association between BB use and BMD. © 2020 American Society for Bone and Mineral Research (ASBMR).

Advances in mesenchymal stem cell transplantation for the treatment of osteoporosis

Osteoporosis is a systemic metabolic bone disease with characteristics of bone loss and microstructural degeneration. The personal and societal costs of osteoporosis are increasing year by year as the ageing of population, posing challenges to public health care. Homing disorders, impaired capability of osteogenic differentiation, senescence of mesenchymal stem cells (MSCs), an imbalanced microenvironment, and disordered immunoregulation play important roles during the pathogenesis of osteoporosis. The MSC transplantation promises to increase osteoblast differentiation and block osteoclast activation, and to rebalance bone formation and resorption. Preclinical investigations on MSC transplantation in the osteoporosis treatment provide evidences of enhancing osteogenic differentiation, increasing bone mineral density, and halting the deterioration of osteoporosis. Meanwhile, the latest techniques, such as gene modification, targeted modification and co-transplantation, are promising approaches to enhance the therapeutic effect and efficacy of MSCs. In addition, clinical trials of MSC therapy to treat osteoporosis are underway, which will fill the gap of clinical data. Although MSCs tend to be effective to treat osteoporosis, the urgent issues of safety, transplant efficiency and standardization of the manufacturing process have to be settled. Moreover, a comprehensive evaluation of clinical trials, including safety and efficacy, is still needed as an important basis for clinical translation.

Lycium barbarum polysaccharide (LBP) inhibits palmitic acid (PA)-induced MC3T3-E1 cell apoptosis by regulating miR-200b-3p/Chrdl1/PPARγ

Background

Obesity is closely related to osteoporosis. Lycium barbarum polysaccharides (LBPs) have anti-osteoporosis activity.

Objective

This study aimed to explore the role of LBPs in palmitic acid (PA)-induced osteoblast apoptosis.

Methods

The microarray data set GSE37676 was downloaded from Gene Expression Ominibus (GEO) database. Top 300 differentially expressed genes (DEGs) were used to construct a protein–protein interaction (PPI) network based on STRING database, and significant modules were analyzed and their key genes were screened by using Cytoscape software. COEXPEDIA database showed that there was co-expression between Chrdl1 and peroxisome proliferator-activated receptor (PPARγ). MC3T3-E1 cells were treated with 100–500 μg/mL of PA. Reverse transcription polymerase chain reaction (RT-PCR) and western blot assays were used to detect mRNA and protein levels. Cell Counting Kit-8 (CCK-8) assay and flow cytometry were used to detect cell viability and cell apoptosis.

Results

Chrdl1 was the key gene from the most significant module and downregulation in MC3T3-E1 cells treated with PA. MicroRNA miR-200b-3p and PPARγ were significantly upregulated among PA-treated MC3T3-E1 cells. The results of luciferase reporter gene assay showed that miR-200b-3p targeted Chrdl1 3’-UTR. Over-expressing miR-200b-3p promoted PA-induced cell apoptosis and inhibited cell viability. After pre-treating cells with PA and LBP, MC3T3-E1 cell apoptosis rate was relatively lower than that of mimics+PA₂₀₀ group. Chrdl1 inhibition partly reversed miR-200b-3p effect on inhibiting apoptosis among MC3T3-E1 cells pre-treated with LBP and PA. Decreased C CASP3, PPARγ and increased Chrdl1 by miR-200b-3p inhibition were partly reversed by Chrdl1 inhibition.

Conclusions

LBPs inhibit PA-induced MC3T3-E1 cell apoptosis by mainly decreasing miR-200b-3p to upregulate Chrdl1, but miR-200b-3p/Chrdl1/PPARγ is not the only mechanism for LBPs protecting osteoblasts from PA.

The Mediation of miR-34a/miR-449c for Immune Cytokines in Acute Cold/Heat-Stressed Broiler Chicken

Simple Summary

In the intensive and scale poultry industry, the level of heat stress (HS) directly affects the growth, development, and production performance of poultry. To alleviate the adverse effects of stress in broilers, microRNA (miRNA) was regarded as a potential regulator of immune cytokines. In this study, through the sequencing analysis of spleens after cold/heat stress, we found that 33 and 37 miRNA were differentially expressed in the heat stress group compared with the normal (NS) group and cold stress (CS) group, respectively. The differential miRNA were mainly involved in biological processes such as the cytokine–cytokine receptor interaction. To further understand the miRNA-mediated effect of heat stress on the immune level of chickens, we selected miR-34a and miR-449c as the research objects, predicted and verified that interleukin 2 (IL-2) and interleukin 12α (IL-12α) were the target genes of miR-34a and miR-449c. Coupled with the analysis of the expression of other cytokines, we found that miRNA could change the expression of immune cytokines directly or indirectly. This discovery provides a new insight into the mediation of miRNA for immune cytokines in acute cold/heat stressed broiler chicken.

Abstract

An increasing amount of evidence has revealed that microRNAs (miRNAs) participated in immune regulation and reaction to acute cold and heat stresses. As a new type of post-transcriptional regulatory factor, miRNA has received widespread attention; However, the specific mechanism used for this regulation still needs to be determined. In this study, thirty broilers at the same growth period were divided into three groups and treated with different temperature and humidity of CS (10–15 °C and 90% Relative Humidity (RH)), HS (39 °C and 90% RH), and NS (26 °C and 50–60% RH) respectively. After 6 h, splenic tissues were collected from all study groups. miRNA sequencing was performed to identify the differentially expressed miRNAs (DEMs) between HS, CS, and NS. We found 33, 37, and 7 DEMs in the HS-NS, HS-CS, CS-NS group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEMs were significantly enriched in cytokine–cytokine receptor interaction and functioned as the cellular responders to stress. We chose two miRNA, miR-34a and miR-449c, from the same family and differential expressed in HS-CS and HS-NS group, as the research objects to predict and verify the target genes. The dual-luciferase reporter assay and quantitative real-time PCR (qRT-PCR) confirmed that two cytokines, IL-2 and IL-12α, were the direct target genes of miR-34a and miR-449c. To further understand the mediation mechanism of miRNAs in acute cold/heat-stressed broiler chicken, a splenic cytokines profile was constructed. The results showed that IL-1β was strongly related to acute heat stress in broiler chicken, and from this we predicted that the increased expression of IL-1β might promote the expression of miR-34a, inducing the upregulation of interferon-γ (INF-γ) and IL-17. Our finds have laid a theoretical foundation for the breeding of poultry resistance and alleviation of the adverse effects of stress.

Circulating MicroRNAs as Novel Biomarkers for Osteoporosis and Fragility Fracture Risk: Is There a Use in Assessment Risk?

Osteoporosis is a multifactorial skeletal disease that is associated with both bone mass decline and microstructure damage. The fragility fractures-especially those affecting the femur-that embody the clinical manifestation of this pathology continue to be a great medical and socioeconomic challenge worldwide. The currently available diagnostic tools, such as dual energy X-ray absorptiometry, Fracture Risk Assessment Tool (FRAX) score, and bone turnover markers, show limited specificity and sensitivity; therefore, the identification of alternative approaches is necessary. As a result of their advantageous features, such as non-invasiveness, biofluid stability, and easy detection, circulating cell-free miRs are promising new potential biomarkers for the diagnosis of osteoporosis and low-traumatic fracture risk assessment. However, due to the absence of both standardized pre-analytical, analytical, and post-analytical protocols for their measurement and universally accepted guidelines for diagnostic use, their clinical utility is limited. The aim of this review was to record all the data currently available in the literature concerning the use of circulating microRNAs as both potential biomarkers for osteoporosis diagnosis and fragility fracture risk evaluation, and group them according to the experimental designs, in order to support a more conscious choice of miRs for future research in this field.

Upregulation of hsa-miR-31-3p induced by ultraviolet affects keratinocytes permeability barrier by targeting CLDN1

Chronic actinic dermatitis (CAD) is a photoallergic skin disease with complicated pathogenesis. However, skin barrier dysfunction may be involved according to clinical manifestation. To investigate the mechanism of CAD barrier dysfunction, noninvasive detection of skin barrier and small RNA sequencing were carried out. Quantitative real-time PCR (qRT-PCR) was used to evaluate the expression levels of hsa-miR-31-3p and CLDN1. The correlation between hsa-miR-31-3p and CAD severity was explored. Further, dual-luciferase reporter assay was performed to identify the relationship between hsa-miR-31-3p and CLDN1. In addition, expression of hsa-miR-31-3p was detected after ultraviolet (UV) irradiation. Influences of hsa-miR-31-3p on primary human keratinocytes barrier were assessed by FITC-Dextran permeability assay. Moreover, western blot was used to detect the expression of claudin-1, filaggrin, loricrin and involucrin. Our results showed that transepidermal water loss (TEWL) significantly increased in CAD, while stratum corneum hydration (SCH) significantly decreased. The expression of hsa-miR-31-3p was up-regulated in CAD while CLDN1 was down-regulated. Hsa-miR-31-3p was correlated with TEWL, UV-MED (minimal erythema dose) and clinical severity scores of CAD (CSS-CAD). Dual-luciferase reporter assay confirmed that hsa-miR-31-3p targeted the 3'UTR region of CLDN1. Moreover, hsa-miR-31-3p was induced by UVB (0-30 mJ/cm²) and UVA (0-4 J/cm²). Furthermore, overexpression of hsa-miR-31-3p increased FITC-Dextran flux of primary human keratinocytes and reduced the expression of claudin-1, filaggrin, loricrin and involucrin. In conclusion, we demonstrated that hsa-miR-31-3p induced by UV was correlated with CAD severity, which played an important role in regulating keratinocytes permeability barrier through targeting CLDN1.

The Role of MicroRNAs in Bone Metabolism and Disease

Bone metabolism is an intricate process involving various bone cells, signaling pathways, cytokines, hormones, growth factors, etc., and the slightest deviation can result in various bone disorders including osteoporosis, arthropathy, and avascular necrosis of femoral head. Osteoporosis is one of the most prevalent disorders affecting the skeleton, which is characterized by low bone mass and bone mineral density caused by the disruption in the balanced process of bone formation and bone resorption. The current pharmaceutical treatments such as bisphosphonates, selective estrogen receptor modulator, calcitonin, teriparatide, etc., could decrease the risk of fractures but have side-effects that have limited their long term applications. MicroRNAs (miRNAs) are one of many non-coding RNAs. These are single-stranded with a length of 19–25 nucleotides and can influence various cellular processes and play an important role in various diseases. Therefore, in this article, we review the different functions of different miRNA in bone metabolism and osteoporosis to understand their mechanism of action for the development of possible therapeutics.

Identification of circRNA-associated ceRNA network in BMSCs of OVX models for postmenopausal osteoporosis

Circular RNAs (circRNAs) serve as competing endogenous RNAs (ceRNAs) and indirectly regulate gene expression through shared microRNAs (miRNAs). However, the potential circRNAs functioning as ceRNAs in osteoporosis remain unclear. The bone marrow mesenchymal stem cells (BMSCs) were isolated from ovariectomy (OVX) mice and controls. We systematically analyzed RNA‐seq and miRNA‐microarray data, miRNA‐target interactions, and prominently coexpressed gene pairs to identify aberrantly expressed circRNAs, miRNAs, and messenger RNAs (mRNAs) between the OVX mice and controls. A total of 45 circRNAs, 22 miRNAs, and 548 mRNAs were significantly dysregulated (fold change > 1.5; p < 0.05). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were conducted for differentially expressed mRNAs, and subsequently a circRNA‐associated ceRNA network involved in osteoporosis was constructed. We identified two ceRNA regulatory pathways in this osteoporosis mouse model—novel circRNA 0020/miR-206-3p/Nnmt and circRNA 3832/miR-3473e/Runx3, which were validated by real-time PCR. This is the first study to elucidate the circRNA-associated ceRNA network in OVX and control mice using deep RNA-seq and RNA-microarray analysis. The data further expanded the understanding of circRNA-associated ceRNA networks, and the regulatory functions of circRNAs, miRNAs and mRNAs in the pathogenesis and pathology of osteoporosis.

MicroRNA Alterations for Diagnosis, Prognosis, and Treatment of Osteoporosis: A Comprehensive Review and Computational Functional Survey

Osteoporosis (OP) is a systemic bone disease with a series of clinical symptoms. The use of screening biomarkers in OP management is therefore of clinical significance, especially in the era of precision medicine and intelligent healthcare. MicroRNAs (miRNAs) are small, non-coding RNAs with the potential to regulate gene expression at the post-transcriptional level. Accumulating evidence indicates that miRNAs may serve as biomarkers for OP prediction and prevention. However, few studies have emphasized the role of miRNAs in systems-level pathogenesis during OP development. In this article, literature-reported OP miRNAs were manually collected and analyzed based on a systems biology paradigm. Functional enrichment studies were performed to decode the underlying mechanisms of miRNAs in OP etiology and therapeutics in three-dimensional space, i.e., integrated miRNA–gene–pathway analysis. In particular, interactions between miRNAs and three well-known OP pathways, i.e., estrogen–endocrine, WNT/β-catenin signaling, and RANKL/RANK/OPG, were systematically investigated, and the effects of non-genetic factors on personalized OP prevention and therapy were discussed. This article is a comprehensive review of OP miRNAs, and bridges the gap between an understanding of OP pathogenesis and clinical translation.

Circular RNA hsa_circ_0076906 competes with OGN for miR-1305 biding site to alleviate the progression of osteoporosis

Osteoporosis is a skeletal disorder, the pathogenic factors of which include the decreased ability of osteogenesis and enhanced osteolysis. Human-derived mesenchymal stem cells (hMSCs) possess the differential capacity to osteoblasts and chondrocytes, so the application of hMSCs in bone tissue is promising to be effective. A group of RNAs which lack of 5' and 3'ends called circular RNAs (circRNAs) were discovered. In this study, we described a previously found circular RNA, circ_0076906, to bind miR-1305 and regulate its target gene, Osteoglycin (OGN), thus regulate osteogenic differentiation of hMSCs and alleviate the progression of osteoporosis. Osteogenic differentiation induced in hMSCs; qRT-PCR and western blot to examine the expressions of mRNAs and proteins; Alkaline phosphatase activity and Alizarin red staining to examine bone formation; luciferase report experiments to detect the interaction between molecules; and the nuclear/cytoplasm separation of cells. 1. Circ_0076906 was induced in osteogenic differentiation; 2. Circ_0076906 silencing inhibited osteogenesis-related genes in hMSCs; 3. Circ_0076906 acted as a sponge for miR-1305; 4. MiR-1305 regulated OGN expression; 5. Circ_0076906 induced-osteogenic differentiation depended on miR-1305/ OGN pathway. Circ_0076906 relieved osteoporosis and promoted osteogenic differentiation through the miR-1305/ OGN pathway.