Differentially expressed circulating miRNAs in postmenopausal osteoporosis: a meta-analysis

Eupatilin ameliorates postmenopausal osteoporosis via elevating microRNA-211-5p and repressing Janus kinase 2/Signal transducer and activator of transcription 3 pathway

This study explored the effect of Eupatilin on postmenopausal osteoporosis and explored the mechanisms associated with miR-211-5p. First, the rats were given intragastric administration of Eupatilin every day and subcutaneously injected once a week with oligonucleotides or plasmids that interfered with the expression of miR-211-5p or Janus kinase 2 (JAK2). After 4 weeks, a rat model of osteoporosis was established. Then, serum alkaline phosphatase, calcium and phosphorus levels were detected, as well as femur bone mineral density and biomechanical parameters. HE staining and Masson staining were applied for detecting the pathological condition of femur while immunohistochemical staining was for detecting the positive expression of osteocalcin. In addition, MC3T3-E1 cells were transfected with plasmid vectors interfering with miR-211-5p or JAK2, and cell viability, lactate dehydrogenase cytotoxicity, and cell mineralization were subsequently examined. The relationship between miR-211-5p and JAK2/Signal transducer and activator of transcription 3 (STAT3) pathway was analyzed, and the targeting of miR-211-5p and JAK2 was also verified. The experimental results found that Eupatilin improved the pathological conditions of osteoporotic rats by promoting the proliferation and mineralization of osteoblasts. miR-211-5p was down-regulated and JAK2/STAT3 were up-regulated in osteoporotic rats. Upregulation of miR-211-5p further improved the pathological conditions of osteoporotic rats based on Eupatilin treatment. MiR-211-5p inhibited the JAK2/STAT3 pathway. Upregulation of JAK2 reversed the effects of elevated miR-211-5p on osteoporotic rats. Overall, Eupatilin attenuates postmenopausal osteoporosis through elevating miR-211-5p and repressing JAK2/STAT3 pathway.

Eupatilin ameliorates postmenopausal osteoporosis via elevating microRNA-211-5p and repressing JAK2/STAT3 pathway

Postmenopausal osteoporosis (PMOP) poses a significant threat to women's health worldwide. Eupatilin is a key bioactive component of the Chinese herbal medicine Artemisia asiatica Nakai. Recent research reports have proved the inhibitory function of Eupatilin in many diseases. MicroRNAs (miRNAs) are 21-23 nucleotide-long, single-stranded, noncoding RNA molecules generated endogenously, and many studies have indicated that miRNAs are involved in the development of osteoporosis. This study explored the role and potential mechanism of Eupatilin underlying PMOP. First, rats were given intragastric administration of Eupatilin every day and subcutaneous injections of oligonucleotides or plasmids that interfered with miR-211-5p or janus kinase 2 (JAK2) once a week. After 4 weeks, the PMOP rat model was established. Then, serum alkaline phosphatase, calcium, and phosphorus levels, as well as femur bone mineral density and biomechanical parameters, were detected. Hematoxylin-eosin staining and Masson staining were applied for detecting the pathological condition of femur, and immunohistochemical staining was for detecting osteocalcin. MC3T3-E1 cells were transfected with plasmid vectors interfering with miR-211-5p or JAK2; and cell viability, lactate dehydrogenase cytotoxicity, and cell mineralization were subsequently examined. The relationship between miR-211-5p and JAK2/signal transducer and activator of transcription 3 (STAT3) pathway was analyzed. The targeting relation between miR-211-5p and JAK2 was also verified. The experimental results revealed that Eupatilin improved the pathological conditions of PMOP rats by promoting the proliferation and mineralization of osteoblasts. MiR-211-5p was down-regulated and JAK2/STAT3 was upregulated in PMOP rats. Upregulation of miR-211-5p further improved the pathological conditions of PMOP rats based on Eupatilin treatment. MiR-211-5p inhibited the JAK2/STAT3 pathway. JAK2 offset the effects of elevated miR-211-5p on PMOP rats. Overall, Eupatilin attenuates PMOP through elevating miR-211-5p and repressing JAK2/STAT3 pathway, which suggests the utility of Eupatilin as a potential drug for POMP treatment.

Up-regulation of plasma miRNA-21 and miRNA-422a in postmenopausal osteoporosis

BACKGROUND

Many researchers focused on diverse miRNAs in the progression of osteoporosis in postmenopausal women. This study aimed to evaluate the association between plasma miRNA-21-5p and miRNA-422a with osteoporosis in postmenopausal women.

METHODS

This cross-sectional comparative study was performed on 126 randomly selected postmenopausal women aged 50-65, including 65 osteoporotic and 61 normal-bone mineral density (BMD) women. miRNA-21 and miRNA-422a were identified using qRT-PCR in these women. BMD was evaluated by the dual-energy X-ray absorptiometry method. A binary logistic regression model adjusted for confounders was used to evaluate the associations between plasma miRNAs' expression levels and osteoporosis. The Area Under Curve (AUC) was calculated to differentiate low BMD in the postmenopausal period using Receiver-Operator Characteristic (ROC) curves.

RESULTS

miRNA-21 and miRNA-422a were significantly up-regulated in osteoporotic compared to non-osteoporotic postmenopausal women. The expression levels of miRNA-21 and miRNA-422a indicated a significant reverse correlation with both lumbar spine and femoral neck density. After adjusting the confounders, the likelihood of osteoporosis in the postmenopausal women with under the median plasma levels of miRNA-21 (OR = 0.025; 95% CI: 0.003 to 0.198, p<0.001) and miRNA-422a (OR = 0.037; 95% CI: 0.007 to 0.211, p<0.001) was significantly less than the women with the levels above the median. There were significant inverse correlations between miRNA-21 (p<0.001, r = -0.511) and miRNA-422a (p<0.001, r = -0.682) with BMD-lumbar spine as well as an inverse correlation between miRNA-21(p<0.001, r = -0.374) and miRNA-422a (p<0.001, r = -0.602) with BMD-femoral neck. The AUC (95%CI) for miRNA-21 and miRNA-422a was 0.84 (0.77 to 0.91) and 0.98 (0.96 to 0.99), respectively. ROC analysis illustrated that sensitivity and specificity values were 83.1% and 74%, respectively, for miRNA-21 at the cut-off point of 3.38. Also, at the cut-off point of 2.86, a sensitivity of 94% as well as a specificity of 89% was determined for miRNA-422a.

CONCLUSIONS

This study indicated that the odds of osteoporosis in postmenopausal women increased with the higher expression of plasma miRNA-21 and miRNA-422a.

Risk of primary osteoporosis score (RPOPs): an algorithm model for primary osteoporosis risk assessment in grass-roots hospital

BACKGROUND

This study aimed to develop and validate a lasso regression algorithm model which was established by correlation factors of bone mineral density (BMD) and could be accurately predicted a high-risk population of primary osteoporosis (POP). It provides a rapid, economical and acceptable early screening method for osteoporosis in grass-roots hospitals.

METHODS

We collected 120 subjects from primary osteoporosis screening population in Zhejiang Quhua Hospital between May 2021 and November 2021 who were divided into three groups (normal, osteopenia and osteoporosis) according to the BMD T-score. The levels of three micro-RNAs in the plasma of these people were detected and assessed by qRT-PCR. At the same time, the levels of β-CTX and t-P1NP in serum of the three groups were determined. Based on the cluster random sampling method, 84 subjects (84/120, 70%) were selected as the training set and the rest were the test set. Lasso regression was used to screen characteristic variables and establish an algorithm model to evaluate the population at high risk of POP which was evaluated and tested in an independent test cohort. The feature variable screening process was used 10-fold cross validation to find the optimal lambda.

RESULTS

The osteoporosis risk score was established in the training set: Risk of primary osteoporosis score (RPOPs) = -0.1497785 + 2.52Age - 0.19miR21 + 0.35miR182 + 0.17β-CTx. The sensitivity, precision and accuracy of RPOPs in an independent test cohort were 79.17%, 82.61% and 75%, respectively. The AUC in the test set was 0.80. Some risk factors have a significant impact on the abnormal bone mass of the subjects. These risk factors were female (p = 0.00013), older than 55 (p < 2.2e-16) and BMI < 24 (p = 0.0091) who should pay more attention to their bone health.

CONCLUSION

In this study, we successfully constructed and validated an early screening model of osteoporosis that is able to recognize people at high risk for developing osteoporosis and remind them to take preventive measures. But it is necessary to conduct further external and prospective validation research in large sample size for RPOPs prediction models.

Interactome of PTH-Regulated miRNAs and Their Predicted Target Genes for Investigating the Epigenetic Effects of PTH (1-34) in Bone Metabolism

Osteoporosis is a metabolic bone disease that mostly affects the elderly. A lot of drugs are available, mostly with an antiresorptive effect but just a few with an osteoanabolic effect, meaning they promote bone building. PTH (1-34) or teriparatide is an osteoanabolic drug, but its efficacy varies between individuals. We performed a literature review and extracted a dataset of 62 microRNAs (miRNAs) from 10 different studies; predicted miRNA target interactions (MTIs) were obtained with the help of four software tools: DIANA, miRWalk, miRDB and TargetScan. With the construction of an interactome of PTH-regulated miRNAs and their predicted target genes, we elucidated miR-146a-5p, miR-551b-5p, miR-205-3p, miR-33a-3p, miR-338-5p as miRNAs with the most interactions and miR-410-3p as the miRNA targeting bone-related pathways with the highest significance. These miRNAs could help in further understanding the mechanism of action of PTH on bone metabolism and osteoporosis. They also have the potential for novel network-based biomarkers for osteoporosis treatment efficacy and safety and as new therapeutic targets.

A preliminary examination of the association between locomotive syndrome and circulating miRNA-199 in community-dwelling people: The Yakumo study

BACKGROUND

The risk of locomotive syndrome (LS) has been proposed as a criterion for evaluating physical ability. The expression levels of circulating miRNAs (c-miRNAs) are predictors of various diseases. This preliminary study aimed to evaluate the relationship between serum levels of several miRNAs and LS.

METHODS

We enrolled 423 participants in whom we conducted a survey with the 25-question Geriatric Locomotive Function Scale (GLFS-25) and measured the serum levels of 21 c-miRNAs. The relationship between the GLFS-25 and each c-miRNA was evaluated with a linear regression analysis, and independent associations between the GLFS-25 and each c-miRNA were assessed with a multiple regression analysis using various independent variables.

RESULTS

Only the serum level of miR-199 was significantly associated with LS after adjustment for age, BMI, sex, and all comorbidities. The receiver operating characteristics curve for the predictive value of the miR-199 level to indicate the presence or absence of LS risk had an area under the curve (AUC) of 0.576 (95% confidence interval: 0.501-0.651).

CONCLUSION

The expression level of miRNA-199 was associated with the risk of LS in community-dwelling Japanese people.

Non-coding RNAs and their cross-talks impacting reproductive health of women

Non-coding RNAs (ncRNAs) work as crucial posttranscriptional modulators of gene expression regulating a wide array of biological processes that impact normal physiology, including reproductive health. The health of women, especially reproductive health, is now a prime focus of society that ensures the females' overall physical, social, and mental well-being. Furthermore, there has been a growing cognizance of ncRNAs' possible applications in diagnostics and therapeutics of dreaded diseases. Hence, understanding the functions and mode of actions of ncRNAs in the context of women's health will allow us to develop effective prognostic and therapeutic strategies that will enhance the quality of life of women. Herein, we summarize recent progress on ncRNAs, such as microRNAs (miRNAs) and long ncRNAs (lncRNAs), and their implications in reproductive health by tying the knot with lifestyle factors that affect fertility complications, pregnancy outcomes, and so forth. We also discourse the interplay among the RNA species, especially miRNAs, lncRNAs, and protein-coding RNAs, through the competing endogenous RNA regulations in diseases of women associated with maternal and fetal health. This review provides new perspectives correlating ncRNAs, lifestyle, and reproductive health of women, which will attract future studies to improve women's lives. This article is categorized under: RNA in Disease and Development > RNA in Disease Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.

A systematic review of miRNAs as biomarkers in osteoporosis disease

Background

Osteoporosis is often considered to be a disease of the elderly, which is characterized by two characteristics: low bone mineral density (BMD) and increased risk of fracture. MicroRNAs (miRNAs) have been reported to play a potential role in bone formation and resorption, bone remodeling, bone homeostasis regulation, and bone cell differentiation. Therefore, altered expression of different miRNAs may impact the pathology of bone diseases such as osteoporosis. A systematic review was conducted to extract all miRNA found to be significantly dys-regulated in the peripheral blood.

Methods

This review was carried out using a systematically search on PubMed, Scopus, Embase, Web of Science (WoS), and Cochrane databases from 1990 to 2018 to explore the diagnostic value of miRNAs as a biomarker in osteoporosis.

Results

A total of 31 studies were identified in the systematic review that indicated more than 30 kinds of up-regulated and down-regulated miRNAs in three categories; postmenopausal osteoporosis, postmenopausal osteoporosis with fracture risk, and other types of osteoporosis and fracture risk.

Conclusion

The collective data presented in this review indicate that miRNAs could serve as biomarkers for the diagnosis (onset) and prognosis (progression of osteoporosis), while the clinical application of these findings has yet to be verified.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00873-5.

Perspective of the GEMSTONE Consortium on Current and Future Approaches to Functional Validation for Skeletal Genetic Disease Using Cellular, Molecular and Animal-Modeling Techniques

The availability of large human datasets for genome-wide association studies (GWAS) and the advancement of sequencing technologies have boosted the identification of genetic variants in complex and rare diseases in the skeletal field. Yet, interpreting results from human association studies remains a challenge. To bridge the gap between genetic association and causality, a systematic functional investigation is necessary. Multiple unknowns exist for putative causal genes, including cellular localization of the molecular function. Intermediate traits ("endophenotypes"), e.g. molecular quantitative trait loci (molQTLs), are needed to identify mechanisms of underlying associations. Furthermore, index variants often reside in non-coding regions of the genome, therefore challenging for interpretation. Knowledge of non-coding variance (e.g. ncRNAs), repetitive sequences, and regulatory interactions between enhancers and their target genes is central for understanding causal genes in skeletal conditions. Animal models with deep skeletal phenotyping and cell culture models have already facilitated fine mapping of some association signals, elucidated gene mechanisms, and revealed disease-relevant biology. However, to accelerate research towards bridging the current gap between association and causality in skeletal diseases, alternative in vivo platforms need to be used and developed in parallel with the current -omics and traditional in vivo resources. Therefore, we argue that as a field we need to establish resource-sharing standards to collectively address complex research questions. These standards will promote data integration from various -omics technologies and functional dissection of human complex traits. In this mission statement, we review the current available resources and as a group propose a consensus to facilitate resource sharing using existing and future resources. Such coordination efforts will maximize the acquisition of knowledge from different approaches and thus reduce redundancy and duplication of resources. These measures will help to understand the pathogenesis of osteoporosis and other skeletal diseases towards defining new and more efficient therapeutic targets.

miR-542-3p Attenuates Bone Loss and Marrow Adiposity Following Methotrexate Treatment by Targeting sFRP-1 and Smurf2

Intensive methotrexate (MTX) treatment for childhood malignancies decreases osteogenesis but increases adipogenesis from the bone marrow stromal cells (BMSCs), resulting in bone loss and bone marrow adiposity. However, the underlying mechanisms are unclear. While microRNAs (miRNAs) have emerged as bone homeostasis regulators and miR-542-3p was recently shown to regulate osteogenesis in a bone loss context, the role of miR-542-3p in regulating osteogenesis and adipogenesis balance is not clear. Herein, in a rat MTX treatment-induced bone loss model, miR-542-3p was found significantly downregulated during the period of bone loss and marrow adiposity. Following target prediction, network construction, and functional annotation/ enrichment analyses, luciferase assays confirmed sFRP-1 and Smurf2 as the direct targets of miR-542-3p. miRNA-542-3p overexpression suppressed sFRP-1 and Smurf2 expression post-transcriptionally. Using in vitro models, miR-542-3p treatment stimulated osteogenesis but attenuated adipogenesis following MTX treatment. Subsequent signalling analyses revealed that miR-542-3p influences Wnt/β-catenin and TGF-β signalling pathways in osteoblastic cells. Our findings suggest that MTX treatment-induced bone loss and marrow adiposity could be molecularly linked to miR-542-3p pathways. Our results also indicate that miR-542-3p might be a therapeutic target for preserving bone and attenuating marrow fat formation during/after MTX chemotherapy.

Circulating miR-122-5p and miR-375 as Potential Biomarkers for Bone Mass Recovery after Parathyroidectomy in Patients with Primary Hyperparathyroidism: A Proof-of-Concept Study

Primary hyperparathyroidism (PHPT) is the leading cause of secondary osteoporosis. Although bone mineral density (BMD) tends to recover after parathyroidectomy in PHPT patients, the degree of recovery varies. Circulating microRNAs (miRNAs) profiles are known to be correlated with osteoporosis and fracture. We aimed to investigate whether osteoporotic fracture-related miRNAs are associated with postoperative BMD recovery in PHPT. Here, 16 previously identified osteoporotic fracture-related miRNAs were selected. We analyzed the association between the preoperative level of each miRNA and total hip (TH) BMD change. All 12 patients (among the 18 patients enrolled) were cured of PHPT after parathyroidectomy as parathyroid hormone (PTH) and calcium levels were restored to the normal range. Preoperative miR-19b-3p, miR-122-5p, and miR-375 showed a negative association with the percent changes in TH BMD from baseline. The association remained robust for miR-122-5p and miR-375 even after adjusting for sex, age, PTH, and procollagen type 1 N-terminal propeptide levels in a multivariable model. In conclusion, preoperative circulating miR-122-5p and miR-375 levels were negatively associated with TH BMD changes after parathyroidectomy in PHPT patients. miRNAs have the potential to serve as predictive biomarkers of treatment response in PHPT patients, which merits further investigation.

Differentially expressed miRNAs in bone after methotrexate treatment

Previous studies have shown that administration of antimetabolite methotrexate (MTX) caused a reduced trabecular bone volume and increased marrow adiposity (bone/fat switch), for which the underlying molecular mechanisms and recovery potential are unclear. Altered expression of microRNAs (miRNAs) has been shown to be associated with dysregulation of osteogenic and/or adipogenic differentiation by disrupting target gene expression. First, the current study confirmed the bone/fat switch following MTX treatment in precursor cell culture models in vitro. Then, using a rat intensive 5-once daily MTX treatment model, this study aimed to identify miRNAs associated with bone damage and recovery (in a time course over Days 3, 6, 9, and 14 after the first MTX treatment). RNA isolated from bone samples of treated and control rats were subjected to miRNA array and reverse transcription-polymerase chain reaction validation, which identified five upregulated miRNA candidates, namely, miR-155-5p, miR-154-5p, miR-344g, miR-6215, and miR-6315. Target genes of these miRNAs were predicted using TargetScan and miRDB. Then, the protein-protein network was established via STRING database, after which the miRNA-key messenger RNA (mRNA) network was constructed by Cytoscape. Functional annotation and pathway enrichment analyses for miR-6315 were performed by DAVID database. We found that TGF-β signaling was the most significantly enriched pathway and subsequent dual-luciferase assays suggested that Smad2 was the direct target of miR-6315. Our current study showed that miR-6315 might be a vital regulator involved in bone and marrow fat formation. Also, this study constructed a comprehensive miRNA-mRNA regulatory network, which may contribute to the pathogenesis/prognosis of MTX-associated bone loss and bone marrow adiposity.

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.

Silencing of miR-483-5p alleviates postmenopausal osteoporosis by targeting SATB2 and PI3K/AKT pathway

Postmenopausal osteoporosis (PMOP) poses a significant threat to women's health worldwide. However, detailed molecular mechanism and therapeutic strategy for PMOP remain insufficient. Accumulating evidence suggests that miR-48-5p is implicated in the pathogenesis of osteoporosis. The present study aimed to determine the role and mechanism of miR-483-5p in PMOP. Results from PMOP patients demonstrated that miR-483-5p was up-regulated and SATB2 was down-regulated. Luciferase reporter assay identified SATB2 as a direct target gene of miR-483-5p. Experiments in MC3T3-E1 cells indicated that miR-483-5p mimic markedly inhibited cell viability as well as the expressions of OPG, RUNX2 and BMP2. And miR-483-5p inhibitor, SATB2-overexpressed lentiviruses (Lv-SATB2) or LY294002 (PI3K/AKT inhibitor) significantly reversed the above results. Similarly, PI3K/AKT signaling was activated by miR-483-5p mimic, and was inhibited in miR-483-5p inhibitor, Lv-SATB2 or LY294002 treated cells. In vivo experiments showed that miR-483-5p inhibitor significantly increased the bone mineral density and biomechanical parameters of femurs in ovariectomized (OVX) rats by targeting SATB2. In addition, the osteogenic differentiation and PI3K/AKT signaling were also regulated by miR-483-5p-SATB2 axis. Taken together, our findings indicated that miR-483-5p contributed to the pathogenesis of PMOP by inhibiting SATB2 and activating PI3K/AKT pathway. MiR-483-5p/SATB2 could be selected as a potential therapeutic target for PMOP.

Overexpression of miR125b Promotes Osteoporosis Through miR-125b-TRAF6 Pathway in Postmenopausal Ovariectomized Rats

BACKGROUND

Postmenopausal osteoporosis is one of the most common types of osteoporosis that women suffer from. Studies involving molecular mechanisms for designing better therapeutic strategies for postmenopausal osteoporosis are still rare. The present study investigates the role of miR-125b in postmenopausal osteoporosis.

METHODS

Microarray analysis was done to screen the gene database. Tissue samples of postmenopausal women were collected to study the miRNA profiles. MC3T3-E1 cells were used and were submitted for transfection. CCK-8 assay was done to check the viability of cells, whereas toxicity was done by lactate dehydrogenase assay kit. TargetScan was done to target genes of miR-125b followed by confirmation by Luciferase reporter assay. For animal studies a rat model of ovariectomized rats was created. Bone mineral density and biomechanics were measured by densitometer. The mRNA levels were assessed by qRT-PCR and proteins by Western blot assay.

RESULTS

miR-125b was over-expressed in human osteoporosis samples. In vitro studies suggested that miR-125b suppressed the cell viability and promoted release of LDH, it also enhanced the RANKL/OPG ratio and suppressed levels of BMP2 and Runx2. Bioinformatics identified TRAF6 as a potential target of miR-125b, further confirmed by luciferase assay, also miR-125b negatively regulated the levels of TRAF6 gene in osteoporosis bones involving the JAK2/STAT3 cascade. In the rat model, miR-125b decreased the bone mineral density and biomechanical parameters in bones by altering the TRAF6 gene involving the JAK2/STAT3 pathway.

CONCLUSION

The outcomes suggested that miR-125b was responsible for the development of postmenopausal osteoporosis and promoted its progression by the TRAF6 gene via the JAK2/STAT3 pathway.

Genetic variability in noncoding RNAs: involvement of miRNAs and long noncoding RNAs in osteoporosis pathogenesis

The pathogenesis of osteoporosis is multifactorial and is the consequence of genetic, hormonal and lifestyle factors. Epigenetics, including noncoding RNA (ncRNA) deregulation, represents a link between susceptibility to develop the disease and environmental influences. The majority of studies investigated the expression of ncRNAs in osteoporosis patients; however, very little information is available on their genetic variability. In this review, we focus on two classes of ncRNAs: miRNAs and long noncoding RNAs (lncRNAs). We summarize recent findings on how polymorphisms in miRNAs and lncRNAs can perturb the lncRNA/miRNA/mRNA axis and may be involved in osteoporosis clinical outcome. We also provide a general overview on databases and bioinformatic tools useful for associating miRNAs and lncRNAs variability with complex genetic diseases.

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.

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.

Circulating Plasma microRNA to Differentiate Cushing's Disease From Ectopic ACTH Syndrome

Corticotropinomas and adrenocorticotropic hormone (ACTH)-secreting neuroendocrine tumors exhibit differential levels of some microRNAs (miRs) compared to normal tissue. Because miRs can be released from tissues into circulation, they offer promise as novel disease biomarkers. Objective: To evaluate whether miRs are differentially detected in plasma samples of patients with ACTH-dependent Cushing's syndrome (CS). Design: Case-control study. Methods: Morning fasting plasma samples were collected from 41 consecutive patients with confirmed ACTH-dependent CS and 11 healthy subjects and stored at -80°C. Twenty-one miRs previously reported to be differentially expressed in ACTH-secreting tumors vs. healthy tissue samples were quantified in plasma by qPCR. Results: Among enrolled subjects, 28 were confirmed to have Cushing's disease (CD), 13 had ectopic ACTH secretion (EAS) and 11 were healthy controls. We found statistically significant differences in the circulating levels of miR-16-5p [45.04 (95% CI 28.77-61.31) in CD vs. 5.26 (2.65-7.87) in EAS, P < 0.001; q = 0.001], miR-145-5p [0.097 (0.027-0.167) in CD vs. undetectable levels in EAS, P = 0.008; q = 0.087] and differences in miR-7g-5p [1.842 (1.283-2.400) in CD vs. 0.847 (0.187-1.507) in EAS, P = 0.02; q = 0.14]. The area under the receiver-operator (ROC) curve was 0.879 (95% CI 0.770-0.987), p < 0.001, when using miR-16-5p to distinguish between CD and EAS. Circulating levels of miR-16-5p in the healthy control group differed from that of both the CD and EAS groups. Conclusions: Plasma miR levels differ in patients with CD and EAS. In particular, miR-16-5p, miR-145-5p and miR-7g-5p are promising biomarkers for further research to differentiate ACTH-dependent CS.

MiR-151a-3p Promotes Postmenopausal Osteoporosis by Targeting SOCS5 and Activating JAK2/STAT3 Signaling

Postmenopausal osteoporosis, the most common type of primary osteoporosis, poses a significant threat to women's health worldwide. However, detailed molecular mechanism and therapeutic strategy for postmenopausal osteoporosis remain insufficient. Increasing evidence suggests that microRNAs contributed to the pathogenesis of osteoporosis and could be considered as potential therapeutic targets. In this study, we found that miR-151a-3p was upregulated in osteoporosis samples. Experiments in MC3T3-E1 cells indicated that miR-151a-3p significantly inhibited cell viability and promoted lactate dehydrogenase release, as well as increased RANKL/OPG ratio and decreased Runx2 and BMP2 expressions. SOCS5 was identified as a direct target gene of miR-151a-3p, which was confirmed by luciferase reporter assay. Moreover, an inverse correlation between miR-151a-3p and SOCS5 was observed in osteoporosis femurs. In addition, JAK2/STAT3 pathway was found to be involved in the progress of osteoporosis mediated by miR-151a-3p-SOCS5 axis. In vivo, ovariectomized (OVX) rat model was established to simulate postmenopausal osteoporosis. The results revealed that miR-151a-3p significantly decreased the bone mineral density and biomechanical parameters of femurs in OVX rats by targeting SOCS5, and that JAK2/STAT3 pathway is a downstream target of miR-151a-3p-SOCS5 axis in OVX rats. In conclusion, our findings suggested that miR-151a-3p contributed to the pathogenesis of postmenopausal osteoporosis, and promoted its progress by targeting SOCS5 and activating JAK2/STAT3 signaling. Thus, anti-miR-151a-3p could be a potential therapeutic strategy for postmenopausal osteoporosis.