MiR-138-5p targets RUNX2 to inhibit osteogenic differentiation of aortic valve interstitial cells via Wnt/β-catenin signaling pathway

Advances in Pathophysiological Mechanisms of Degenerative Aortic Valve Disease

Degenerative aortic valve disease (DAVD) represents the most prevalent valvular ailment among the elderly population, which significantly impacts their physical well-being and potentially poses a lethal risk. Currently, the underlying mechanisms of DAVD remain incompletely understood. While the progression of this disease has traditionally been attributed to degenerative processes associated with aging, numerous recent studies have revealed that heart valve calcification may represent a response of valve tissue to a specific initiating factor, involving the interaction of various genes and signaling pathways. This calcification process is further influenced by a range of factors, including genetic predispositions, environmental exposures, metabolic factors, and hemodynamic considerations. Based on the identification of its biomarkers, potential innovative therapeutic targets are proposed for the treatment of this complex condition. The present article primarily delves into the underlying pathophysiological mechanisms and advancements in diagnostic and therapeutic modalities pertaining to this malady.

The Role of microRNA in the Regulation of Differentiation and the Functionality of Osteoblasts, Osteoclasts, and Their Precursors in Osteoporosis

Osteoporosis is a complex disease that is affected by a variety of factors, including genetic and epigenetic influences. While DNA markers for osteoporosis have been identified, they do not fully explain the hereditary basis of the disease. Epigenetic factors, such as small microRNAs (miRNAs), may provide a missing link in understanding the molecular mechanisms underlying osteoporosis. miRNAs are a class of non-coding RNAs that play a role in the epigenetic regulation of gene expression. They are known to be involved in various biological processes, including bone formation and remodelling. Differential expression of miRNAs has been linked to the pathological decrease in bone mineral density associated with osteoporosis. It has been shown that an abnormal miRNA expression pattern leads to a decrease in osteoblast activity and an increase in osteoclast activity. Further research into the role of miRNAs in osteoporosis may help to better understand this disease and identify potential therapeutic targets for treatment. Based on these assumptions, the study of miRNA expression patterns in osteoblasts, osteoclasts, and their precursors under normal and osteoporotic conditions is a rapidly growing field of scientific research. Although the results of this research are still incomplete and sometimes contradictory, they require additional scientific analysis to better understand the complex mechanisms involved. The purpose of this paper is to review the current research on miRNAs specifically expressed in osteoblasts and osteoclasts under both normal and pathological conditions. We will also discuss the potential applications of these miRNAs as biomarkers for osteoporosis diagnosis and as targets for osteoporosis treatment.

Noncoding RNA regulates the expression of Krm1 and Dkk2 to synergistically affect aortic valve lesions

Calcific aortic valve disease (CAVD) is becoming an increasingly important global medical problem, but effective pharmacological treatments are lacking. Noncoding RNAs play a pivotal role in the progression of cardiovascular diseases, but their relationship with CAVD remains unclear. Sequencing data revealed differential expression of many noncoding RNAs in normal and calcified aortic valves, with significant differences in circHIPK3 and miR-182-5p expression. Overexpression of circHIPK3 ameliorated aortic valve lesions in a CAVD mouse model. In vitro experiments demonstrated that circHIPK3 inhibits the osteogenic response of aortic valve interstitial cells. Mechanistically, DEAD-box helicase 5 (DDX5) recruits methyltransferase 3 (METTL3) to promote the N6-methyladenosine (m6A) modification of circHIPK3. Furthermore, m6A-modified circHIPK3 increases the stability of Kremen1 (Krm1) mRNA, and Krm1 is a negative regulator of the Wnt/β-catenin pathway. Additionally, miR-182-5p suppresses the expression of Dickkopf2 (Dkk2), the ligand of Krm1, and attenuates the Krm1-mediated inhibition of Wnt signaling. Activation of the Wnt signaling pathway significantly contributes to the promotion of aortic valve calcification. Our study describes the role of the Krm1-Dkk2 axis in inhibiting Wnt signaling in aortic valves and suggests that noncoding RNAs are upstream regulators of this process.

MiR-138-5p Inhibits Thyroid Cancer Cell Growth and Stemness by Targeting TRPC5/Wnt/β-Catenin Pathway

MicroRNAs play a key role in the pathogenesis of many types of cancer, including thyroid cancer (TC). MiR-138-5p has been confirmed to be abnormally expressed in TC tissues. However, the role of miR-138-5p in TC progression and its potential molecular mechanism need to be further explored. In this study, quantitative real-time PCR was used to examine miR-138-5p and TRPC5 expression, and western blot analysis was performed to examine the protein levels of TRPC5, stemness-related markers, and Wnt pathway-related markers. Dual-luciferase reporter assay was used to assess the interaction between miR-138-5p and TRPC5. Cell proliferation, stemness, and apoptosis were examined using colony formation assay, sphere formation assay, and flow cytometry. Our data showed that miR-138-5p could target TRPC5 and its expression was negatively correlated with TRPC5 expression in TC tumor tissues. MiR-138-5p decreased proliferation, stemness, and promoted gemcitabine-induced apoptosis in TC cells, and this effect could be reversed by TRPC5 overexpression. Moreover, TRPC5 overexpression abolished the inhibitory effect of miR-138-5p on the activity of Wnt/β-catenin pathway. In conclusion, our data showed that miR-138-5p suppressed TC cell growth and stemness via the regulation of TRPC5/Wnt/β-catenin pathway, which provided some guidance for studying the potential function of miR-138-5p in TC progression.

The Wnt/β-catenin pathway is involved in 2,5-hexanedione-induced ovarian granulosa cell cycle arrest

N-Hexane causes significant ovarian toxicity, and its main active metabolite 2,5-hexanedione (2,5-HD) can induce ovarian injury through mechanisms such as inducing apoptosis in ovarian granulosa cells (GCs); however, the specific mechanism has not been fully elucidated. In this study, we investigated the effects on the cell cycle of rat ovarian GCs exposed in vitro to different concentrations of 2,5-HD (0 mM, 20 mM, 40 mM, and 60 mM) and further explored the mechanism by mRNA and miRNA microarray analyses. The flow cytometry results sindicated that compared with control cells, in ovarian GCs, there was significant cell cycle arrest after 2,5-HD treatment. Cell cycle- and apoptosis- related gene (Cdk2, Ccnd1, Bax, Bcl-2, Caspase3, and Caspase9) expression was altered. The mRNA and miRNA microarray results suggested that 5678 mRNAs and 32 miRNAs were differentially expressed in the 2,5-HD-treated group. A total of 262 target mRNAs were obtained by miRNA and mRNA coexpression analysis, forming 368 miRNA-mRNA coexpression relationship pairs with 27 miRNAs. GO and KEGG analyses showed that differentially expressed genes were significantly enriched in the cell cycle and Wnt signaling pathways. Furthermore, significant changes in the expression of Wnt signaling pathway and cell cycle- related genes (Fzd1, Lrp6, Tcf3, Tcf4, Fzd6, Lrp5, β-catenin, Lef1, GSK3β, and Dvl3) after 2,5-HD treatment were confirmed by qRT-PCR and Western blotting. Ther results of dual-luciferase assays indicated decreased β-catenin/TCF transcriptional activity after 2,5-HD treatment. In addition, Wnt pathway-related miRNAs (rno-miR-145-5p, rno-miR-143-3p, rno-miR-214-3p, rno-miR-138-5p, and rno-miR-199a-3p) were changed significantly after 2,5-HD treatment. In summary, 2,5-HD induced cell cycle arrest in ovarian GCs, and the Wnt/β-catenin signaling pathway may play a very critical role in this process. Alterations in the expression of miRNAs such as rno-miR-145-5p may have significant implications.

MicroRNA-138: an emerging regulator of skeletal development, homeostasis, and disease

Noncoding microRNAs are powerful epigenetic regulators of cellular processes by their ability to target and suppress expression of numerous protein-coding mRNAs. This multitargeting function is a unique and complex feature of microRNAs. It is now well-described that microRNAs play important roles in regulating the development and homeostasis of many cell/tissue types, including those that make up the skeletal system. In this review, we focus on microRNA-138 (miR-138) and its effects on regulating bone and cartilage cell differentiation and function. In addition to its reported role as a tumor suppressor, miR-138 appears to function as an inhibitor of osteoblast differentiation. This review provides additional information on studies that have attempted to alter miR-138 expression in vivo as a means to dampen ectopic calcification or alter bone mass. However, a review of the published literature on miR-138 in cartilage reveals a number of contradictory and inconclusive findings with respect to regulating chondrogenesis and chondrocyte catabolism. This highlights the need for more research in understanding the role of miR-138 in cartilage biology and disease. Interestingly, a number of studies in other systems have reported miR-138-mediated effects in dampening inflammation and pain responses. Future studies will reveal if a multifunctional role of miR-138 involving suppression of ectopic bone, inflammation, and pain will be beneficial in skeletal conditions such as osteoarthritis and heterotopic ossification.

Icariin promotes osteogenic differentiation through the mmu_circ_0000349/mmu-miR-138-5p/Jumonji domain-containing protein-3 axis

Circular RNAs (circRNAs) regulate Jumonji domain-containing protein-3 (JMJD3) by sponging with microRNAs (miRNAs). This study aimed to investigate the role of icariin on specific circRNA/miRNA/JMJD3 axis in osteogenic differentiation of MC3T3-E1 cells. CircRNA sequencing was performed on the MC3T3-E1 cells induced by osteogenic differentiation medium for 1 d (negative control (NC) group) and 14 d (osteogenesis group). And mmu_circ_0000349 was verified using Sanger sequencing, ribonuclease R degradation, and actinomycin D assay. The function of mmu_circ_0000349 was validated by detecting the expressions of osteogenic differentiation markers, alkaline phosphatase (ALP), and runt-related transcription (RUNX2), via real-time quantitative PCR (qPCR) and Western blotting or ALP and alizarin red staining assay. Dual luciferase reporter gene assay confirmed the relationship between mmu_circ_0000349 and mmu-miR-138-5p (or mmu-miR-138-5p and JMJD3). Meanwhile, the JMJD3 binding to mmu_circ_0000349 was screened using an RNA pull-down assay. qPCR and Western blotting confirmed the effect of icariin on the mmu_circ_0000349/mmu-miR-138-5p/JMJD3 axis and osteogenic differentiation. As MC3T3-E1 osteogenic differentiation progressed, the JMJD3 expression level increased. A total of 361 circRNAs exhibited differences between the NC and osteogenesis groups. After validation, mmu_circ_0000349 was further analyzed as it exhibited the largest expression. And mmu_circ_0000349 was identified as a stable circular structure. Overexpression of mmu_circ_0000349 increased the expression levels of ALP and RUNX2, enhanced ALP activity, and increased the number of mineralized nodules; contrarily, inhibition of mmu_circ_0000349 exerted opposite effects. The data also confirmed that mmu_circ_0000349 regulated JMJD3 by sponging with mmu-miR-138-5p. With the increase in icariin concentration and time for treatment, the expression levels of mmu_circ_0000349, JMJD3, ALP, and RUNX2 also increased, whereas that of mmu-miR-138-5p decreased. In conclusion, Icariin promoted osteogenic differentiation by regulating the mmu_circ_0000349/mmu-miR-138-5p/JMJD3 pathway. Therefore, this provides a theoretical basis for the treatment of diseases related to osteogenic differentiation.

The Role of MicroRNAs in Aortic Stenosis-Lessons from Recent Clinical Research Studies

Aortic stenosis (AS) is the most prevalent primary valve lesion demanding intervention. Two main treatment options are surgical aortic valve replacement or transcatheter aortic valve implantation. There is an unmet need for biomarkers that could predict treatment outcomes and become a helpful tool in guiding Heart Team in the decision-making process. Micro-ribonucleic acids (microRNAs/miRs) have emerged as potential biomarkers thoroughly studied in recent years. In this review, we aimed to summarize the current knowledge about the role of miRNAs in AS based on human subject research. Much research investigating miRNAs' role in AS has been conducted so far. We included 32 original human subject research relevant to the discussed field. Most of the presented miRNAs were studied only by a single research group. Nevertheless, several miRNAs appeared more than once, sometimes with high consistency between different studies but sometimes with apparent discrepancies. The molecular aspects of diseases are doubtlessly exciting and provide invaluable insights into the pathophysiology. Nevertheless, translating these findings, regarding biomarkers such as miRNAs, into clinical practice requires much effort, time, and further research with a focus on validating existing evidence.

Abnormal mechanical stress on bicuspid aortic valve induces valvular calcification and inhibits Notch1/NICD/Runx2 signal

Background

Bicuspid aortic valve (BAV) is a congenital cardiac deformity, increasing the risk of developing calcific aortic valve disease (CAVD). The disturbance of hemodynamics can induce valvular calcification, but the mechanism has not been fully identified.

Methods

We constructed a finite element model (FEM) of the aortic valve based on the computed tomography angiography (CTA) data from BAV patients and tricuspid aortic valve (TAV) individuals. We analyzed the hemodynamic properties based on our model and investigated the characteristics of mechanical stimuli on BAV. Further, we detected the expression of Notch, NICD and Runx2 in valve samples and identified the association between mechanical stress and the Notch1 signaling pathway.

Results

Finite element analysis showed that at diastole phase, the equivalent stress on the root of BAV was significantly higher than that on the TAV leaflet. Correspondingly, the expression of Notch1 and NICH decreased and the expression of Runx2 elevated significantly on large BAV leaflet belly, which is associated with equivalent stress on leaflet. Our findings indicated that the root of BAV suffered higher mechanical stress due to the abnormal hemodynamic environment, and the disturbance of the Notch1/NICD/Runx2 signaling pathway caused by mechanical stimuli contributed to valvular calcification.