miR-542-3p prevents ovariectomy-induced osteoporosis in rats via targeting SFRP1

Protocatechualdehyde inhibits iron overload-induced bone loss by inhibiting inflammation and oxidative stress in senile rats

The accumulating evidence has made it clear that iron overload is a crucial mechanism in bone loss. Protocatechualdehyde (PCA) has also been used to prevent osteoporosis in recent years. Whether PCA can reverse the harmful effects of iron overload on bone mass in aged rats is still unknown. Therefore, this study aimed to assess the role of PCA in iron overload-induced bone loss in senile rats. In the aged rat model, we observed that iron overload affects bone metabolism and bone remodeling, manifested by bone loss and decreased bone mineral density. The administration of PCA effectively mitigated the detrimental effects caused by iron overload, and concomitant reduction in MDA serum levels and elevation of SOD were noted. In addition, PCA-treated rats were observed to have significantly increased bone mass and elevated expression of SIRT3，BMP2，SOD2 and reduced expression of TNF-α in bone tissue. We also observed that PCA was able to reduce oxidative stress and inflammation and restore the imbalance in bone metabolism. When MC3T3-E1 and RAW264.7 cells induced osteoblast and osteoclasts differentiation, PCA intervention could significantly recover the restriction of osteogenic differentiation and up-regulation of osteoclast differentiation treated by iron overload. Further, by detecting changes in ROS, SOD, MDA, expression of SIRT3 and mitochondrial membrane potentials, we confirm that the damage caused to cells by iron overload is associated with decreased SIRT3 activity, and that 3-TYP have similar effects on oxidative stress caused by FAC. In conclusion, PCA can resist iron overload-induced bone damage by improving SIRT3 activity, anti-inflammatory and anti-oxidative stress.

MicroRNAs and their Modulatory Effect on the Hallmarks of Osteosarcopenia

PURPOSE OF THE REVIEW

Osteosarcopenia is a geriatric syndrome associated with disability and mortality. This review summarizes the key microRNAs that regulate the hallmarks of sarcopenia and osteoporosis. Our objective was to identify components similarly regulated in the pathology and have therapeutic potential by influencing crucial cellular processes in both bone and skeletal muscle.

RECENT FINDINGS

The simultaneous decline in bone and muscle in osteosarcopenia involves a complex crosstalk between these tissues. Recent studies have uncovered several key mechanisms underlying this condition, including the disruption of cellular signaling pathways that regulate bone remodeling and muscle function and regeneration. Accordingly, emerging evidence reveals that dysregulation of microRNAs plays a significant role in the development of each of these hallmarks of osteosarcopenia. Although the recent recognition of osteosarcopenia as a single diagnosis of bone and muscle deterioration has provided new insights into the mechanisms of these underlying age-related diseases, several knowledge gaps have emerged, and a deeper understanding of the role of common microRNAs is still required. In this study, we summarize current evidence on the roles of microRNAs in the pathogenesis of osteosarcopenia and identify potential microRNA targets for treating this condition. Among these, microRNAs-29b and -128 are upregulated in the disease and exert adverse effects by inhibiting IGF-1 and SIRT1, making them potential targets for developing inhibitors of their activity. MicroRNA-21 is closely associated with the occurrence of muscle and bone loss. Conversely, microRNA-199b is downregulated in the disease, and its reduced activity may be related to increased myostatin and GSK3β activity, presenting it as a target for developing analogues that restore its function. Finally, microRNA-672 stands out for its ability to protect skeletal muscle and bone when expressed in the disease, highlighting its potential as a possible therapy for osteosarcopenia.

Identification of miRNAs related to osteoporosis by high-throughput sequencing

Background

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

Objective

To screen for and validate miRNAs associated with osteoporosis.

Method

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

Results

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

Conclusion

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

Screening and Analysis of Core Genes for Osteoporosis Based on Bioinformatics Analysis and Machine Learning Algorithms

Objective

This study aimed to identify osteoporosis-related core genes using bioinformatics analysis and machine learning algorithms.

Methods

mRNA expression profiles of osteoporosis patients were obtained from the Gene Expression Profiles (GEO) database, with GEO35958 and GEO84500 used as training sets, and GEO35957 and GSE56116 as validation sets. Differential gene expression analysis was performed using the R software "limma" package. A weighted gene co-expression network analysis (WGCNA) was conducted to identify key modules and modular genes of osteoporosis. Kyoto Gene and Genome Encyclopedia (KEGG), Gene Ontology (GO), and gene set enrichment analysis (GSEA) were performed on the differentially expressed genes. LASSO, SVM-RFE, and RF machine learning algorithms were used to screen for core genes, which were subsequently validated in the validation set. Predicted microRNAs (miRNAs) from the core genes were also analyzed, and differential miRNAs were validated using quantitative real-time PCR (qPCR) experiments.

Results

A total of 1280 differentially expressed genes were identified. A disease key module and 215 module key genes were identified by WGCNA. Three core genes (ADAMTS5, COL10A1, KIAA0040) were screened by machine learning algorithms, and COL10A1 had high diagnostic value for osteoporosis. Four core miRNAs (has-miR-148a-3p, has-miR-195-3p, has-miR-148b-3p, has-miR-4531) were found by intersecting predicted miRNAs with differential miRNAs from the dataset (GSE64433, GSE74209). The qPCR experiments validated that the expression of has-miR-195-3p, has-miR-148b-3p, and has-miR-4531 was significantly increased in osteoporosis patients.

Conclusion

This study demonstrated the utility of bioinformatics analysis and machine learning algorithms in identifying core genes associated with osteoporosis.

The MicroRNAs in the Pathophysiology of Osteoporosis

Globally, osteoporosis is the most common systemic skeletal disease. There are many factors that influence osteoporosis' development and progression. During the pathogenesis of this disease, bone turnover is imbalanced between resorption and the formation of bone tissue. A growing interest has been devoted to the role that microRNA (miRNA) plays in osteoporosis regulation. A microRNA (miRNA) is a group of small single-stranded RNA molecules involved in regulating gene expression in eukaryotic organisms. As microRNAs (miRNAs) are key regulators of gene expression and can modulate processes related to bone metabolism, they have become increasingly important for studying osteoporosis pathogenesis. The available research suggests that miRNAs play an important role in regulating processes associated with bone metabolism, especially by influencing bone resorption and synthesis. Furthermore, microRNAs can also serve as potential therapeutic targets for osteoporosis, besides being a rapid and specific biomarker.

Osteoporosis: interferon-gamma-mediated bone remodeling in osteoimmunology

As the world population ages, osteoporosis, the most common disease of bone metabolism, affects more than 200 million people worldwide. The etiology is an imbalance in bone remodeling process resulting in more significant bone resorption than bone remodeling. With the advent of the osteoimmunology field, the immune system's role in skeletal pathologies is gradually being discovered. The cytokine interferon-gamma (IFN-γ), a member of the interferon family, is an important factor in the etiology and treatment of osteoporosis because it mediates bone remodeling. This review starts with bone remodeling process and includes the cellular and key signaling pathways of bone remodeling. The effects of IFN-γ on osteoblasts, osteoclasts, and bone mass are discussed separately, while the overall effects of IFN-γ on primary and secondary osteoporosis are summarized. The net effect of IFN-γ on bone appears to be highly dependent on the environment, dose, concentration, and stage of cellular differentiation. This review focuses on the mechanisms of bone remodeling and bone immunology, with a comprehensive discussion of the relationship between IFN-γ and osteoporosis. Finding the paradoxical balance of IFN-γ in bone immunology and exploring the potential of its clinical application provide new ideas for the clinical treatment of osteoporosis and drug development.

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.

miR-344d-3p regulates osteogenic and adipogenic differentiation of mouse mandibular bone marrow mesenchymal stem cells

Postmenopausal osteoporosis (POP) is a chronic disease of bone metabolism that occurs in middle-aged and elderly women. POP can cause abnormalities of the skeletal system in the whole body, and the jaw bone is also impacted, affecting the function of the oral and maxillofacial regions. Mandibular bone marrow mesenchymal stem cells (MBMSCs) play an important role in mandibular bone metabolism, and abnormal differentiation of MBMSCs can affect the metabolic balance between new and old bone. MicroRNAs (miRNAs) can induce the differentiation of MBMSCs. In this study, the changes in biological characteristics of mandible and MBMSCs in the bone microenvironment of postmenopausal osteoporosis were firstly analyzed, and then the key miRNAs screened from miRNAs gene chips were sorted out for verification and functional exploration. It was found that miR-344d-3p promoted the osteogenic differentiation of MC3T3-E1 and MBMSCs. It inhibited the adipogenic differentiation of 3T3-L1 and MBMSCs. In addition, Dnmt3a may be the target gene of miR-344d-3p. In conclusion, this study found new biological indicators related to bone metabolism, which are of great significance in the field of bone reconstruction.

Marsdenia tenacissima extract prevents the malignant progression of glioma through upregulating lncRNA MEG3 and SFRP1-dependent inhibition of Wnt/β-catenin pathway

BACKGROUND/AIM

Recent studies have highlighted the tumor-suppressive effect of Marsdenia tenacissima extract (MTE) on human cancers. This research unveils the potential impact of MTE on glioma and ascertains the relevant molecular mechanisms.

METHODS

Glioma cells were treated with MTE, with normal human astrocytes (NHAs) as controls. A battery of function experiments, including the CCK-8 viability test, colony formation assay, scratch migration assay, and Transwell invasion assay, was executed to address the responses of glioma cells to MTE treatment and gain or loss of function of lncMEG3, miR-542-3p, and SFRP1. FISH, RIP, and dual-luciferase reporter assays were adopted for assessing gene interactions. U251-GFP-Luc cells were delivered into nude mice through intracranial injection to develop an orthotopic glioma model for in vivo validation.

RESULTS

200 mg/mL MTE could suppress the proliferating, migrating, and invading properties of glioma cells but not affect those of NHAs. MTE treatment enhanced the expression of lncMEG3, which competes with SFRP1 for binding miR-542-3p. SFRP1 could inactivate the Wnt/β-catenin pathway. Animal experimentation substantiated the antitumor activity and mechanism of MTE in nude mice.

CONCLUSIONS

MTE suppresses glioma via the lncMEG3/miR-542-3p/SFRP1/Wnt/β-catenin axis. These findings contribute to a theoretical basis for the use of MTE for glioma patients.

WTAP-mediated m6A modification modulates bone marrow mesenchymal stem cells differentiation potential and osteoporosis

An imbalance in the differentiation potential of bone marrow mesenchymal stem cells (BMSCs) is an important pathogenic mechanism underlying osteoporosis (OP). N6-methyladenosine (m⁶A) is the most common post-transcriptional modification in eukaryotic cells. The role of the Wilms' tumor 1-associated protein (WTAP), a member of the m⁶A functional protein family, in regulating BMSCs differentiation remains unknown. We used patient-derived and mouse model-derived samples, qRT-PCR, western blot assays, ALP activity assay, ALP, and Alizarin Red staining to determine the changes in mRNA and protein levels of genes and proteins associated with BMSCs differentiation. Histological analysis and micro-CT were used to evaluate developmental changes in the bone. The results determined that WTAP promoted osteogenic differentiation and inhibited adipogenic differentiation of BMSCs. We used co-immunoprecipitation (co-IP), RNA immunoprecipitation (RIP), methylated RNA immunoprecipitation (MeRIP), RNA pulldown, and dual-luciferase assay to explore the direct mechanism. Mechanistically, the expression of WTAP increased during osteogenic differentiation and significantly promoted pri-miR-181a and pri-miR-181c methylation, which was recognized by YTHDC1, and increased the maturation to miR-181a and miR-181c. MiR-181a and miR-181c inhibited the mRNA expression of SFRP1, promoting the osteogenic differentiation of BMSCs. Our results demonstrated that the WTAP/YTHDC1/miR-181a and miR-181c/SFRP1 axis regulated the differentiation fate of BMSCs, suggesting that it might be a potential therapeutic target for osteoporosis.

Sclerostin is involved in osteogenic transdifferentiation of vascular smooth muscle cells in chronic kidney disease-associated vascular calcification with non-canonical Wnt signaling

Vascular calcification is prominent in patients with chronic kidney disease (CKD) and is a strong predictor of cardiovascular mortality in the CKD population. However, the mechanism underlying CKD-associated vascular calcification remains unclear. To identify potential therapeutic targets, a 5/6 nephrectomy rat model was established by feeding of a high-phosphorous diet as the CKD group and compared with sham group rats at 4 and 16 weeks. Sequencing analyses of the rat aorta revealed 643 upregulated and 1023 downregulated genes at 4 weeks, as well as 899 upregulated and 1185 downregulated genes at 16 weeks in the CKD group compared to the sham group. Bioinformatics analyses suggested that SOST (which encodes sclerostin) and Wnt signaling are involved in CKD-associated vascular calcification. Furthermore, protein-protein interactions analysis revealed interactions between SOST, WNT5A, and WNT5B, that involved runt-related transcription factor 2 (RUNX2) and transgelin (TAGLN). SOST was increased in CKD-associated vascular calcification following reduction of the Wnt signaling, including WNT5A and WNT5B, both in vivo and in vitro. TargetScan was used to predict the microRNAs (miRNAs) targeting WNT5A and WNT5B. The expression levels of miR-542-3p, miR-298-3p, miR-376b-5p, and miR-3568 were significantly reduced, whereas that of miR-742-3p was significantly increased in calcified rat aortic vascular smooth muscle cells (VSMCs). In CKD rat aortas, the expression of miR-542-3p, miR-298-3p, miR-376b-5p, miR-3568, miR-742-3p, and miR-22-5p were significantly reduced at both 4 and 16 weeks. Altogether, owing to several assessments, potentially diagnostic and prognostic biomarkers for improving common CKD diagnostic tools were identified in this study.

Abbreviations: BUN: blood urea nitrogen; CKD: chronic kidney disease; CKD-MBD: chronic kidney disease-mineral bone disorder; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GO: the Gene Ontology; HE: hematoxylin-eosin; HRP: horseradish peroxidase; KEGG: Kyoto Encyclopedia of Genes and Genomes; MiRNAs: microRNAs; PAS: periodic acid-Schiff; RUNX2: runt-related transcription factor 2; SCr: serum creatinine; STRING: the Search Tool for the Retrieval of Interacting Genes/Proteins; TAGLN: transgelin; VSMC: vascular smooth muscle cell.

Non-coding RNA delivery for bone tissue engineering: progress, challenges and potential solutions

More than 20 million individuals worldwide suffer from congenital or acquired bone defects annually. The development of bone scaffold materials that simulate natural bone for bone defect repair remains challenging. Recently, ncRNA-based therapies for bone defects have attracted increasing interest because of the great potential of ncRNAs in disease treatment. Various types of ncRNAs regulate gene expression in osteogenesis-related cells via multiple mechanisms. The delivery of ncRNAs to the site of bone loss through gene vectors or scaffolds is a potential therapeutic option for bone defect repair. Therefore, this study discusses and summarizes the regulatory mechanisms of miRNAs, siRNAs, and piRNAs in osteogenic signaling and reviews the widely used current RNA delivery vectors and scaffolds for bone defect repair. Additionally, current challenges and potential solutions of delivery scaffolds for bone defect repair are proposed, with the aim of providing a theoretical basis for their future clinical applications.

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.

CircRNA_0001795 sponges miRNA-339-5p to regulate yes-associated protein 1 expression and attenuate osteoporosis progression

Osteoporosis (OP) is one of the most common bone diseases, especially in women after menopause. Increasing evidence shows that non-coding RNAs are implicated in the pathogenesis of OP. In this study, based on the published circular RNA profiling data between OP patients and healthy controls, we found that circRNA_0001795 (circ_0001795) is downregulated in OP samples, which was further validated in the OP samples collected in this study. We therefore investigated the functional role and molecular mechanism of circ_0001795 in the osteogenic differentiation of human bone marrow stromal cells (hBMSCs) hBMSCs by alkaline phosphatase (ALP) activity assay, ALP and Alizarin Red S (ALS) Staining, luciferase reporter assay. Our data revealed that the overexpression of circ_0001795 could significantly promote the osteogenic differentiation of hBMSCs. MiRNA-339-5p (miR-339-5p) was identified as a target of circ_0001795, and miR-339-5p mimic attenuated the effect of circ_0001795 overexpression. MiR-339-5p downregulated yes-associated protein 1 (YAP1), which mediates the effect of circ_0001795 overexpression. Overall, this study uncovered the role of circ_0001795/miR-339-5p/YAP1 axis in regulating osteogenic differentiation, indicating that targeting Circ_0001795 could serve as a novel therapeutic target for OP.

Anti-osteoporosis Effect of Fisetin against Ovariectomy Induced Osteoporosis in Rats: In silico, in vitro and in vivo Activity

Osteoporosis is a bone related disease that is characterised by bone loss that further increases the susceptibility to bone fractures and bone frailty due to disturbances in the micro-architecture of bone tissue. Fisetin (flavonoids) exhibited anti-inflammatory and antioxidative stress effects against various diseases. In this protocol, we make an effort to comfort the anti-osteoporosis effect of fisetin against ovariectomy (OVX) induced osteoporosis. A docking study of fisetin and alendronate on the estrogen (α and β) and vitamin D receptors was carried out. SaOS-2 (osteoblast like human) cells were used for the estimation of cell proliferation. The OVX induced OVX model was used and three doses of fisetin and alendronate was given to rats till 16 weeks. The hormone levels, bone turnover markers and biochemical parameters were estimated. Fisetin was docked into estrogen (α and β) and vitamin D receptors, resulting in stable complexes with lower binding scores. Fisetin significantly (p < 0.001) exhibited the induction of cell proliferation against the SaOS-2 cells. OVX induced osteoporosis rats exhibited a suppression of body weight and uterus index, after the Fisetin treatment. Fisetin treatment significantly (p < 0.001) improved the level of bone mineral content (BMC), bone mineral density (BMD) and biochemical parameters such as energy, maximum load, stiffness, young modules, maximum stress and reduced the level of 1,25(OH) 2 D3 and E 2 . Fisetin treatment significantly (p < 0.001) declined the level of phosphorus (P), calcium (Ca) and boosted the level of VitD. Fisetin treatment significantly (p < 0.001) reduced the malonaldehyde (MDA) level and enhanced the glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) level in the bone, intestine and hepatic tissue. Fisetin treatment suppressed the cytokines, RANKL/OPG ratio, receptor activator of nuclear factor-κB ligand (RANKL) and improved the level of osteoprotegerin (OPG). The findings suggest that fisetin could be a beneficial phytoconstituent for the treatment and prevention of postmenopausal osteoporotic complications.

The SFRP1 Inhibitor WAY-316606 Attenuates Osteoclastogenesis Through Dual Modulation of Canonical Wnt Signaling

Osteoporosis, a noteworthy age-related disease induced by imbalanced osteogenesis and osteoclastogenesis, is a serious economic burden on both individuals and society. Small molecule drugs with dual effects on both bone resorption and mineralization are pressingly needed. Secreted frizzled-related protein 1 (SFRP1), a well-known extracellular repressor of canonical Wnt signaling, has been reported to regulate osteogenesis. Global SFRP1 knockout mice show significantly elevated bone mass. Although osteoclasts (OCs) express and secrete SFRP1, the role of SFRP1 produced by OCs in osteoclastogenesis and osteoporosis remains unclear. In this work, the levels of SFRP1 were found to be increased in patients with osteoporosis compared with healthy controls. Pharmacological inhibition of SFRP1 by WAY-316606 (WAY)- attenuated osteoclastogenesis and bone resorption in vitro. The expressions of OC-specific genes were suppressed by the SFRP1 inhibitor, WAY. Mechanistically, both extracellular and intracellular SFRP1 could block activation of the canonical Wnt signaling pathway, and WAY reverse the silent status of canonical Wnt through dual effects, leading to osteoclastogenesis inhibition and osteogenesis promotion. Severe osteopenia was observed in the ovariectomized (OVX) mouse model, and WAY treatment effectively improved the OVX-induced osteoporosis. In summary, this work found that SFRP1 supports OC differentiation and function, which could be attenuated by WAY through dual modulation of canonical Wnt signaling, suggesting its therapeutic potential. © 2021 American Society for Bone and Mineral Research (ASBMR).

miR-6315 Attenuates Methotrexate Treatment-Induced Decreased Osteogenesis and Increased Adipogenesis Potentially through Modulating TGF-β/Smad2 Signalling

Methotrexate (MTX) treatment for childhood malignancies has shown decreased osteogenesis and increased adipogenesis in bone marrow stromal cells (BMSCs), leading to bone loss and bone marrow adiposity, for which the molecular mechanisms are not fully understood. Currently, microRNAs (miRNAs) are emerging as vital mediators involved in bone/bone marrow fat homeostasis and our previous studies have demonstrated that miR-6315 was upregulated in bones of MTX-treated rats, which might be associated with bone/fat imbalance by directly targeting Smad2. However, the underlying mechanisms by which miR-6315 regulates osteogenic and adipogenic differentiation require more investigations. Herein, we further explored and elucidated the regulatory roles of miR-6315 in osteogenesis and adipogenesis using in vitro cell models. We found that miR-6315 promotes osteogenic differentiation and it alleviates MTX-induced increased adipogenesis. Furthermore, our results suggest that the involvement of miR-6315 in osteogenesis/adipogenesis regulation might be partially through modulating the TGF-β/Smad2 signalling pathway. Our findings indicated that miR-6315 may be important in regulating osteogenesis and adipogenesis and might be a therapeutic target for preventing/attenuating MTX treatment-associated bone loss and marrow adiposity.

lncRNA SNHG1 induced by SP1 regulates bone remodeling and angiogenesis via sponging miR-181c-5p and modulating SFRP1/Wnt signaling pathway

BACKGROUND

We aimed to investigate the functions and underlying mechanism of lncRNA SNHG1 in bone differentiation and angiogenesis in the development of osteoporosis.

METHODS

The differential gene or proteins expressions were measured by qPCR or western blot assays, respectively. The targeted relationships among molecular were confirmed through luciferase reporter, RIP and ChIP assays, respectively. Alkaline phosphatase (ALP), alizarin red S (ARS) and TRAP staining were performed to measure the osteoblast/osteoclast differentiation of BMSCs. The viability, migration and angiogenesis in BM-EPCs were validated by CCK-8, clone formation, transwell and tube formation assays, respectively. Western blot and immunofluorescence detected the cytosolic/nuclear localization of β-catenin. Ovariectomized (OVX) mice were established to confirm the findings in vitro.

RESULTS

SNHG1 was enhanced and miR-181c-5p was decreased in serum and femoral tissue from OVX mice. SNHG1 directly inhibited miR-181c-5p to activate Wnt3a/β-catenin signaling by upregulating SFRP1. In addition, knockdown of SNHG1 promoted the osteogenic differentiation of BMSCs by increasing miR-181c-5p. In contrast, SNHG1 overexpression advanced the osteoclast differentiation of BMSCs and inhibited the angiogenesis of BM-EPCs, whereas these effects were all reversed by miR-181c-5p overexpression. In vivo experiments indicated that SNHG1 silencing alleviated osteoporosis through stimulating osteoblastogenesis and inhibiting osteoclastogenesis by modulating miR-181c-5p. Importantly, SNHG1 could be induced by SP1 in BMSCs.

CONCLUSIONS

Collectively, SP1-induced SNHG1 modulated SFRP1/Wnt/β-catenin signaling pathway via sponging miR-181c-5p, thereby inhibiting osteoblast differentiation and angiogenesis while promoting osteoclast formation. Further, SNHG1 silence might provide a potential treatment for osteoporosis.

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.

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.

Effective Osteogenic Priming of Mesenchymal Stem Cells through LNA-ASOs-Mediated Sfrp1 Gene Silencing

Mesenchymal stem cell (MSC) transplantation has emerged as a promising approach for bone regeneration. Importantly, the beneficial effects of MSCs can be improved by modulating the expression levels of specific genes to stimulate MSC osteogenic differentiation. We have previously shown that Smurf1 silencing by using Locked Nucleic Acid-Antisense Oligonucleotides, in combination with a scaffold that sustainably releases low doses of BMP-2, was able to increase the osteogenic potential of MSCs in the presence of BMP-2 doses significantly smaller than those currently used in the clinic. This would potentially allow an important reduction in this protein in MSs-based treatments, and thus of the side effects linked to its administration. We have further improved this system by specifically targeting the Wnt pathway modulator Sfrp1. This approach not only increases MSC bone regeneration efficiency, but is also able to induce osteogenic differentiation in osteoporotic human MSCs, bypassing the need for BMP-2 induction, underscoring the regenerative potential of this system. Achieving successful osteogenesis with the sole use of LNA-ASOs, without the need of administering pro-osteogenic factors such as BMP-2, would not only reduce the cost of treatments, but would also open the possibility of targeting these LNA-ASOs specifically to MSCs in the bone marrow, allowing us to treat systemic bone loss such as that associated with osteoporosis.

Recent Progresses in the Treatment of Osteoporosis

Osteoporosis (OP) is a chronic bone disease characterized by aberrant microstructure and macrostructure of bone, leading to reduced bone mass and increased risk of fragile fractures. Anti-resorptive drugs, especially, bisphosphonates, are currently the treatment of choice in most developing countries. However, they do have limitations and adverse effects, which, to some extent, helped the development of anabolic drugs such as teriparatide and romosozumab. In patients with high or very high risk for fracture, sequential or combined therapies may be considered with the initial drugs being anabolic agents. Great endeavors have been made to find next generation drugs with maximal efficacy and minimal toxicity, and improved understanding of the role of different signaling pathways and their crosstalk in the pathogenesis of OP may help achieve this goal. Our review focused on recent progress with regards to the drug development by modification of Wnt pathway, while other pathways/molecules were also discussed briefly. In addition, new observations made in recent years in bone biology were summarized and discussed for the treatment of OP.

Roles of MicroRNAs in Osteogenesis or Adipogenesis Differentiation of Bone Marrow Stromal Progenitor Cells

Bone marrow stromal cells (BMSCs) are multipotent cells which can differentiate into chondrocytes, osteoblasts, and fat cells. Under pathological stress, reduced bone formation in favour of fat formation in the bone marrow has been observed through a switch in the differentiation of BMSCs. The bone/fat switch causes bone growth defects and disordered bone metabolism in bone marrow, for which the mechanisms remain unclear, and treatments are lacking. Studies suggest that small non-coding RNAs (microRNAs) could participate in regulating BMSC differentiation by disrupting the post-transcription of target genes, leading to bone/fat formation changes. This review presents an emerging concept of microRNA regulation in the bone/fat formation switch in bone marrow, the evidence for which is assembled mainly from in vivo and in vitro human or animal models. Characterization of changes to microRNAs reveals novel networks that mediate signalling and factors in regulating bone/fat switch and homeostasis. Recent advances in our understanding of microRNAs in their control in BMSC differentiation have provided valuable insights into underlying mechanisms and may have significant potential in development of new therapeutics.

Hsa-miR-5581-3p and Hsa-miR-542-3p Target the F8 Gene in Hemophilia A without F8 Mutations

Objective

This study aims at uncovering the effects of microRNAs (miRNAs) on the F8 gene and FVIII protein in hemophilia A (HA).

Methods

F8-targeting miRNAs were predicted by TargetScan, miRDB, and starBase. MiRNAs, predicted by at least two of the three databases, were selected for further study, and their expressions in the blood of HA patients without F8 mutations and healthy controls were detected. A dual-luciferase reporter assay was performed to verify the binding between hsa-miR-5581-3p/hsa-miR-542-3p and F8. In addition, the regulation of F8 by hsa-miR-5581-3p/hsa-miR-542-3p was investigated in human umbilical vein endothelial cells (HUVECs) and lymphoblastoid cell line (LCL) that displayed endogenous expression of FVIII. qRT-PCR was used to detect the expressions of miRNAs and F8 gene, and Western blotting was conducted to measure the expression of FVIII protein.

Results

A total of 42 F8-targeting miRNAs were predicted by at least two of the three databases. Among these miRNAs, hsa-miR-5581-3p and hsa-miR-542-3p were highly expressed in the blood of HA patients and have not been reported in previous studies of HA. Both hsa-miR-5581-3p and hsa-miR-542-3p could bind the 3′UTR of F8 mRNA. Upregulation of hsa-miR-5581-3p or hsa-miR-542-3p suppressed the expressions of F8 mRNA and FVIII protein in HUVECs and LCL cells.

Conclusion

Hsa-miR-5581-3p and hsa-miR-542-3p target the F8 gene and suppress the expression of FVIII protein, which may contribute to the development of HA without F8 mutations.

Integrated Strategy of Network Pharmacological Prediction and Experimental Validation Elucidate Possible Mechanism of Bu-Yang Herbs in Treating Postmenopausal Osteoporosis via ESR1

Postmenopausal osteoporosis (PMOP) is a type of bone metabolism disease-related to estrogen deficiency with an increasing incidence. Traditional Chinese (TCM) has always been used and showed effectiveness in treating PMOP. In the current study, Bu-Yang herbs were considered to be the most frequently used and efficient TCM herbs in PMOP treatment. However, chemical and pharmacological profiles were not elucidated. Network pharmacology was conducted on representative Bu-Yang herbs (Yin-Yang-Huo. Du-Zhong, Bu-Gu-Zhi, Tu-Si-Zi) to investigate the mechanism of Bu-Yang herbs on PMOP. Chemical compounds, potential targets, and disease related genes were available from the corresponding database. Results showed that Bu-Yang herbs could interact with ESR1 and estrogen signaling pathways. For further validation, the Bu-Yang decoction (BYD), formula consisted of the above-mentioned 4 Bu-Yang herbs was presented for experimental validation. In vivo, BYD significantly reversed ovariectomy (OVX)-induced osteoporosis progress in a dose-dependent manner by up-regulation of bone mineral density and amelioration of bone microarchitecture. In vitro, BYD dramatically improved the proliferation and mineral nodules formation of osteoblasts. Both in vitro and in vivo results illustrated that the phenotype change induced by BYD is correlated with up-regulated of ESR1 and activation of the β-catenin pathway. Meanwhile, inhibition of ESR1 by ICI182, 780 blocked the osteogenic phenotype and β-catenin pathway activation induced by BYD. In conclusion, the current study suggested that Bu-Yang herbs are the most useful TCM herbs in treating PMOP. Furthermore, the integrated strategy of network pharmacology prediction with experimental validation suggested that BYD exerted its anti-PMOP via ESR1 and the downstream mechanism might be activation of the β-catenin signaling pathway.

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.

The roles of miRNA, lncRNA and circRNA in the development of osteoporosis

Osteoporosis is a common metabolic bone disease, influenced by genetic and environmental factors, that increases bone fragility and fracture risk and, therefore, has a serious adverse effect on the quality of life of patients. However, epigenetic mechanisms involved in the development of osteoporosis remain unclear. There is accumulating evidence that epigenetic modifications may represent mechanisms underlying the links of genetic and environmental factors with increased risk of osteoporosis and bone fracture. Some RNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been shown to be epigenetic regulators with significant involvement in the control of gene expression, affecting multiple biological processes, including bone metabolism. This review summarizes the results of recent studies on the mechanisms of miRNA-, lncRNA-, and circRNA-mediated osteoporosis associated with osteoblasts and osteoclasts. Deeper insights into the roles of these three classes of RNA in osteoporosis could provide unique opportunities for developing novel diagnostic and therapeutic approaches to this disease.

Epigenetic Regulation in Mesenchymal Stem Cell Aging and Differentiation and Osteoporosis

Mesenchymal stem cells (MSCs) are a reliable source for cell-based regenerative medicine owing to their multipotency and biological functions. However, aging-induced systemic homeostasis disorders in vivo and cell culture passaging in vitro induce a functional decline of MSCs, switching MSCs to a senescent status with impaired self-renewal capacity and biased differentiation tendency. MSC functional decline accounts for the pathogenesis of many diseases and, more importantly, limits the large-scale applications of MSCs in regenerative medicine. Growing evidence implies that epigenetic mechanisms are a critical regulator of the differentiation programs for cell fate and are subject to changes during aging. Thus, we here review epigenetic dysregulations that contribute to MSC aging and osteoporosis. Comprehending detailed epigenetic mechanisms could provide us with a novel horizon for dissecting MSC-related pathogenesis and further optimizing MSC-mediated regenerative therapies.

Circ-SLC8A1 regulates osteoporosis through blocking the inhibitory effect of miR-516b-5p on AKAP2 expression

BACKGROUND

Osteoporosis is a disease characterized by bone loss, imbalance of bone metabolism and destruction of trabecular microarchitecture. Circular RNAs (circRNAs) have been revealed as important biological regulators in human diseases. The expression characteristics and mechanism of circRNAs in osteoporosis are unclear.

METHODS

The binding sites of miR-516b-5p on circ-SLC8A1 and AKAP2 mRNA were predicted using circAtlas (http://circatlas.biols.ac.cn) and miRDB (http://mirdb.org). Target sites of miR-516b-5p on circ-SLC8A1 and AKAP2 mRNA were confirmed by a dual luciferase assay. The relationship between miR-516b-5p and AKAP2 was determined by a quantitative reverse transcriptase-polymerase chain reaction. Alizarin red S staining and alkaline phosphatase staining were used to observe the level of osteogenic differentiation after transfection.

RESULTS

The first six circRNAs captured from the 30 circRNAs with highest expression in the bone marrow were examined in a mouse model of osteoporosis and the expression of circ-SLC8A1 was found to be significantly reduced in osteoporosis. Circ-SLC8A1 negatively regulated the expression of miR-516b-5p. Overexpression of circ-SLC8A1 blocked the inhibition of AKAP2 by miR-516b-5p.

CONCLUSIONS

Circ-SLC8A1 blocks the inhibitory effect of miR-516b-5p on the downstream target gene AKAP2 and promotes osteoporosis. The findings of the present might help to provide a new strategy for the treatment of osteoporosis.

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.

miR‑483‑3p promotes the osteogenesis of human osteoblasts by targeting Dikkopf 2 (DKK2) and the Wnt signaling pathway

Osteoporosis is a systemic metabolic bone disease during which bone mass decreases and bone quality is reduced. Maintaining the bone formation capacity of osteoblasts is crucial for the treatment of osteoporosis. In the present study, bioinformatics analysis was performed on online microarray expression profiles to identify miRNA(s) related to osteoblast proliferation and bone marrow‑derived mesenchymal stem cell (BMSC) osteogenic differentiation. The specific effects of candidate miRNAs on cell proliferation, osteogenic differentiation and Wnt signaling‑related factors were examined. As regards the downstream mechanisms, online tools were employed to predict the downstream targets of candidate miRNAs and the predicted miRNA‑mRNA binding was verified. Finally, the dynamic effects of miRNAs and mRNAs were examined. The results revealed that miR‑483‑3p expression was decreased in bone tissue samples from patients with osteoporosis. In miR‑483‑3p‑overexpressing human osteoblasts, cell viability, DNA synthesis capacity and osteogenesis were promoted, and the protein levels of Wnt1, β‑catenin and cyclin D1 were increased. However, the protein receptor activator of nuclear factor kappa‑Β ligand (RANKL)/osteoprotegerin (OPG) ratio and cell apoptotic rate were decreased. The Wnt signaling, antagonist Dikkopf 2 (DKK2), was targeted and negatively regulated by miR‑483‑3p. DKK2 knockdown exerted similar effects as miR‑483‑3p overexpression, while DKK2 overexpression inhibited cell viability, DNA synthesis capacity and osteogenesis. DKK2 overexpression also decreased the Wnt1, β‑catenin, and cyclin D1 protein levels, whereas it promoted the the RANKL/OPG ratio and the apoptosis of human osteoblasts. DKK2 overexpression reversed the functions of miR‑483‑3p overexpression. On the whole, the findings of the present study demonstrate that the miR‑483‑3p/DKK2 axis modulates the bone formation process by affecting osteoblast proliferation, pre‑osteoblast differentiation into mature osteoblasts and new bone matrix formation.

MiR-542-3p drives renal fibrosis by targeting AGO1 in vivo and in vitro

AIMS

Renal fibrosis is the typical manifestation of progressive kidney disease and causes a severe threat to human health. Surging evidence has illustrated that miRNA plays a core role in the genesis and development of kidney fibrosis. MiR-542-3p has been testified to function as a facilitator in hepatic stellate cell activation and fibrosis. The purpose of study is to investigate the potential of miR-542-3p in renal tubulointerstitial fibrosis.

MATERIALS AND METHODS

In this study, to establish renal fibrosis model in vivo and in vitro, we first conducted unilateral ureteral obstruction (UUO) on rats and high glucose (HG) treatment on the HK-2 cells. Histological and western blot analyses were utilized for assessment of renal fibrosis model. Luciferase reporter assay was carried out to explore the regulatory mechanism underlying miR-542-3p in renal fibrosis.

KEY FINDINGS

MiR-542-3p was found to be highly expressed in renal fibrosis. Functional experiments revealed that overexpression of miR-542-3p accelerated the deterioration of kidney fibrosis and inhibition of miR-542-3p led to the opposite result. Through the aid of bioinformatics tool, the speculated miR-542-3p binding sites were uncovered in the 3'UTR of argonaute RISC component 1 (AGO1). Mechanism study elucidated that AGO1 was a direct target of miR-542-3p. Lastly, our findings suggested that miR-542-3p played a promoting role in renal fibrosis via repression of AGO1.

SIGNIFICANCE

We justified that miR-542-3p induced kidney fibrogenesis both in vivo and in vitro through targeting AGO1, unveiling that miR-542-3p might be a promising option for the treatment of patients with renal fibrosis.

Role of Secreted Frizzled-Related Protein 1 in Early Mammary Gland Tumorigenesis and Its Regulation in Breast Microenvironment

In mice, the lack of secreted frizzled-related protein 1 (SFRP1) is responsible for mammogenesis and hyperplasia, while, in bovines, its overexpression is associated with post-lactational mammary gland involution. Interestingly, there are no reports dealing with the role of SFRP1 in female involution. However, SFRP1 dysregulation is largely associated with human tumorigenesis in the literature. Indeed, the lack of SFRP1 is associated with both tumor development and patient prognosis. Considering the increased risk of breast tumor development associated with incomplete mammary gland involution, it is crucial to demystify the "grey zone" between physiological age-related involution and tumorigenesis. In this review, we explore the functions of SFRP1 involved in the breast involution processes to understand the perturbations driven by the disappearance of SFRP1 in mammary tissue. Moreover, we question the presence of recurrent microcalcifications identified by mammography. In bone metastases from prostate primary tumor, overexpression of SFRP1 results in an osteolytic response of the tumor cells. Hence, we explore the hypothesis of an osteoblastic differentiation of mammary cells induced by the lack of SFRP1 during lobular involution, resulting in a new accumulation of hydroxyapatite crystals in the breast tissue.

miR-122 Exerts Inhibitory Effects on Osteoblast Proliferation/Differentiation in Osteoporosis by Activating the PCP4-Mediated JNK Pathway

Osteoporosis is characterized by the reduction of bone mineral density and deterioration of bone quality which leads to high risk of fractures. Some microRNAs (miRNAs) have been confirmed as potential modulators of osteoblast differentiation to maintain bone mass maintenance. We aimed to clarify whether miR-122 could regulate osteoblast differentiation in ovariectomized rats with osteoporosis. miR-122 was upregulated and Purkinje cell protein 4 (PCP4) was downregulated in ovariectomized rats. PCP4 was identified as a target of miR-122 by dual-luciferase reporter gene assay. We transfected isolated osteoblasts from ovariectomized rats with miR-122 mimic or inhibitor or PCP4 overexpression vectors. Proliferation and differentiation of osteoblasts were repressed by the overexpression of miR-122 but enhanced by overexpression of PCP4. miR-122 could induce the activation of the c-Jun NH2-terminal kinase (JNK) signaling pathway, while PCP4 blocked this pathway. Rescue experiments further demonstrated that the inhibiting effects of miR-122 on osteoblast differentiation could be compensated by activation of the PCP4 or inhibition of JNK signaling pathway. Collectively, our data imply that miR-122 inhibits osteoblast proliferation and differentiation in rats with osteoporosis, highlighting a novel therapeutic target for osteoporotic patients.

Secreted Frizzled-related proteins (sFRPs) in osteo-articular diseases: much more than simple antagonists of Wnt signaling?

Osteo-articular diseases are characterized by a dysregulation of joint and/or bone homeostasis. These include diseases affecting the joints originally, such as osteoarthritis and rheumatoid arthritis, or the bone, such as osteoporosis. Inflammation and the involvement of Wingless-related integration site (Wnt) signaling pathways are key pathophysiological features of these diseases resulting in tissue degradation by matrix-degrading enzymes, namely matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases with thrombospondin motifs (ADAMTs), secreted by the joint resident cells and/or by infiltrating immune cells. Activation of Wnt signaling pathways is modulated by different families of proteins, including Dickkopfs and the secreted Frizzled-related proteins (sFRPs). The sFRP family is composed of five secreted glycoproteins in mammals that regulate Wnt signaling in the extracellular compartment. Indeed, sFRPs are able to bind both to the soluble Wnt ligands and to their cell membrane receptors, the Frizzled proteins. Their expression profile is altered in osteo-articular diseases, suggesting that they could account for the abnormal activation of Wnt pathways. In the present article, we review how sFRPs are more than simple antagonists of the Wnt signaling pathways and discuss their pathophysiological relevance in the context of osteo-articular diseases. We detail their Wnt-dependent and their Wnt-independent roles, with a particular emphasis on their ability to modulate the inflammatory response and extracellular matrix (ECM) remodeling. We also discuss their potential therapeutic use with a focus on bone remodeling, osteo-articular cancers, and tissue engineering.

Bioinformatic screening and experimental analysis identify SFRP1 as a prognostic biomarker for tongue squamous cell carcinomas

OBJECTIVE

To provide a prognostic biomarker and a potential therapeutic target for tongue squamous cell carcinoma (TSCC).

DESIGN

Screening the prognostic genes of TSCC by bioinformatics, and verifying the correlation between the above genes and the prognosis of TSCC by experiments.

RESULTS

Twenty-four common differentially expressed genes (DEGs) between TSCC and the corresponding normal tissues were screened from four sets of TSCC functional gene expression series in Gene Expression Omnibus (GEO) datasets. Further bioinformatics research based on the data from The Cancer Genome Atlas (TCGA), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) indicate that the low expression of SFRP1 might be correlated with poor prognosis of TSCC patients. By colony formation assay, reverse transcription polymerase chain reaction (RT-PCR), western blotting, immunohistochemical staining, flowcytometry, lentivirus transfection and animal experiments, it was confirmed that the low level of SFRP1 expression correlated with poor prognosis of TSCC patients.

CONCLUSION

This study identified SFRP1 as a novel prognostic biomarker and a potential therapeutic target for TSCC.

MicroRNA-25-3p regulates osteoclasts through nuclear factor I X

Osteoporosis is a bone metabolic disease, characterized by loss of bone density leading to fractures. Its incidence increases with age and affects patient quality of life. Although osteoclasts play a significant role in osteoporosis, their underlying regulatory mechanisms remain unclear. In this study, we found that microRNA (miR)-25-3p negatively regulates osteoclast function through nuclear factor I X (NFIX). Overexpression of NFIX promoted osteoclast proliferation and increased the expression of the osteoclast differentiation and activity markers tartrate-resistant acid phosphatase and cathepsin K. MiR-25-3p transfection inhibited NFIX expression, which in turn inhibited osteoclast proliferation. Collectively, our results suggest that miR-25-3p promotes osteoclast activity by regulating the expression of NFIX. Therefore, targeting miR-25-3p in osteoclasts could be a promising strategy for treating skeletal disorders involving reduced bone formation.

miR-140-3p exhibits repressive functions on preosteoblast viability and differentiation by downregulating MCF2L in osteoporosis

Previous research manifested that miR-140-3p was a latent biomarker for osteoporosis. Nevertheless, the mechanism of miR-140-3p in osteoporosis is still not clear and needs ulteriorly studying. The purpose of our paper was to ulteriorly probe the underlying mechanism of miR-140-3p on osteoporosis. Firstly, based on the data acquired from GEO database, we found that miR-140-3p was highly expressed; meanwhile, MCF2L was lowly expressed in osteoporosis patients. Upregulation/downregulation of miR-140-3p by miR-140-3p mimic/inhibitor restrained/promoted MC3T3-E1 cell viability and differentiation. However, miR-140-3p over-expression/downregulation accelerated/repressed MC3T3-E1 cell apoptosis. MCF2L was forecasted as a target of miR-140-3p by miRanda, miRWalk, and TargetScan miRNA target gene prediction software. Luciferase reporter assay confirmed that MCF2L could be directly targeted by miR-140-3p. Moreover, we identified that the expression of MCF2L was negatively regulated by miR-140-3p. From rescue assays, we discovered that knockdown of MCF2L weakened the promoting influence of miR-140-3p ablation on MC3T3-E1 cell viability and differentiation, and receded the suppressing impact of miR-140-3p reduction on MC3T3-E1 cell apoptosis. Above all, this research disclosed that miR-140-3p repressed preosteoblast viability and differentiation while promoted preosteoblast apoptosis via targeting MCF2L. Our discoveries might afford a theoretical basis of developing a latent novel target for osteoporosis therapy.

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.

Wnt signaling pathway in osteoporosis: Epigenetic regulation, interaction with other signaling pathways, and therapeutic promises

Wnt is a major signaling pathway involved in multifaceted roles of various biological processes. Bones are dynamic tissues which are able to remodel and maintain the tissue homeostasis. Wnt signaling cascade leads to the promotion of bone formation and suppression of bone resorption, leading to a balance in bone remodeling. Recent evidence has reinforced the inevitable role of Wnt signaling in osteoporosis. The complex genetic and epigenetic regulations of Wnt signaling factors and their interaction with other master signaling pathways such as TGF-β, BMP, PI3K/AKT, and Hedgehog outline their importance in diagnosis and treatment of osteoporosis. In this review, we highlighted the recent advances in function of Wnt signaling-related epigenetic regulation, different signaling pathways interacting with Wnt, and their roles in osteoporosis. Finally, we discussed novel promises in molecular targeted therapy of osteoporosis.

CDCA2 promotes the proliferation of colorectal cancer cells by activating the AKT/CCND1 pathway in vitro and in vivo

BACKGROUND

Cell division cycle associated 2 (CDCA2), upregulated in lung adenocarcinoma and oral squamous cell carcinoma, may be related to some malignant diseases. Nevertheless, its role in colorectal cancer (CRC) remains unknown.

METHODS

CDCA2 expression was analyzed using The Cancer Genome Atlas (TCGA), quantitative real-time PCR (qRT-PCR), and immunohistochemistry. The impact of CDCA2 on cell proliferation was analyzed via loss- or gain-of-function assays. Furthermore, gene set enrichment analysis was conducted to explore the potential mechanism of CDCA2 in CRC. Lastly, the expression levels of CCND1 and AKT were measured in CRC cell lines.

RESULTS

Our study revealed that CDCA2 expression was associated with tumor progression. Through loss- or gain-of-function assays, we found that upregulation of CDCA2 promoted the proliferation of DLD-1 cells, however, downregulation of CDCA2 in SW480 cells restrained proliferative capacity both in vitro and in vivo. The results of flow cytometry showed that CDCA2 promoted cell cycle progression via upregulation of CCND1 in CRC cell lines. In the following experiments, we found that CDCA2 regulated CCND1 expression through activating the PI3K/AKT pathway, and confirmed this using a specific PI3K inhibitor (LY294002).

CONCLUSIONS

This study demonstrates that overexpression of CDCA2 might target CCND1 to promote CRC cell proliferation and tumorigenesis through activation of the PI3K/AKT pathway.

Identification of differentially expressed microRNAs in the bone marrow of osteoporosis patients

This study aimed to identify specific microRNAs (miRNAs) related to postmenopausal osteoporosis (OP) in human. A total of 67 conserved miRNAs, including 50 miRNAs significantly up-regulated and 17 miRNAs significantly downregulated, showed differential expression between OP group and control group. 180 hairpin structures were predicted and 199 potential novel miRNA candidates with 18 to 25 nt in length, which will greatly enrich the human miRBase. 4 miRNAs (miR-518b, miR-582-3p, miR-148a-3p and miRNA-223-3p) had upregulated expression and 4 (miR-7d-5p, miR-210-3p, miR-324-5p and miR-654-3p) showed down-regulated expression. Target genes of these miRNAs were involved in bone development, cell proliferation in bone marrow, osteoblast development, negative regulation of osteoblast differentiation, and negative regulation of osteoclast development, as well as several osteogenesis related pathways. Canonical Wnt signaling pathway was selected for verification and function analysis. The expression of Wnt1, FZD10, LRP5, DVL2 and LEF1 was down-regulated significantly, while that of SFRP1, DKK1, and CHD8 was up-regulated markedly. In conclusion, these genes play important roles in OP, which improves our understanding of pathogenesis of OP.

Deregulated miRNAs in bone health: Epigenetic roles in osteoporosis

MicroRNA (miRNA) has shown to enhance or inhibit cell proliferation, differentiation and activity of different cell types in bone tissue. The discovery of miRNA actions and their targets has helped to identify them as novel regulations actors in bone. Various studies have shown that miRNA deregulation mediates the progression of bone-related pathologies, such as osteoporosis. The present review intends to give an exhaustive overview of miRNAs with experimentally validated targets involved in bone homeostasis and highlight their possible role in osteoporosis development. Moreover, the review analyzes miRNAs identified in clinical trials and involved in osteoporosis.

miR-542-3p prevents ovariectomy-induced osteoporosis in rats via targeting SFRP1

Secreted frizzled-related protein-1 (SFRP1) is a negative regulatory molecule of the WNT signaling pathway and serves as a therapeutic target for bone formation in osteoporosis. In this study, we first established an ovariectomized (OVX) rat model to simulate postmenopausal osteoporosis and found significant changes in miR-542-3p and sFRP1 expression by RNA sequencing and qRT-PCR. In addition, there was a significant negative correlation between miR-542-3p and sFRP1 mRNA levels in postmenopausal women with osteoporosis. We found that miR-542-3p inhibited the expression of sFRP1 mRNA by luciferase reporter assay. When the miR-542-3p binding site in sFRP1 3'UTR was deleted, it did not affect its expression. Western blot results showed that miR-542-3p inhibited the expression of SFRP1 protein. The expression of SFRP1 was significantly increased in osteoblast-induced mesenchymal stem cells (MSC), whereas the expression of miR-542-3p was significantly decreased. And miR-542-3p transfected MSCs showed a significant increase in osteoblast-specific marker expression, indicating that miR-542-3p is necessary for MSC differentiation. Inhibition of miR-542-3p reduced bone formation, confirmed miR-542-3p play a role in bone formation in vivo. In general, these data suggest that miR-542-3p play an important role in bone formation via inhibiting SFRP1 expression and inducing osteoblast differentiation.