Inhibiting effect of microRNA-187-3p on osteogenic differentiation of osteoblast precursor cells by suppressing cannabinoid receptor type 2

Exploration of the miR-187-3p/CNR2 pathway in modulating osteoblast differentiation and treating postmenopausal osteoporosis through mechanical stress

This study aimed to explore how mechanical stress affects osteogenic differentiation via the miR-187-3p/CNR2 pathway. To conduct this study, 24 female C57BL/6 mice, aged 8 weeks, were used and divided into four groups. The Sham and OVX groups did not undergo treadmill exercise, while the Sham + EX and OVX + EX groups received a 8-week treadmill exercise. Post-training, bone marrow and fresh femur samples were collected for further analysis. Molecular biology analysis, histomorphology analysis, and micro-CT analysis were conducted on these samples. Moreover, primary osteoblasts were cultured under osteogenic conditions and divided into GM group and CTS group. The cells in the CTS group underwent a sinusoidal stretching regimen for either 3 or 7 days. The expression of early osteoblast markers (Runx2, OPN, and ALP) was measured to assess differentiation. The study findings revealed that mechanical stress has a regulatory impact on osteoblast differentiation. The expression of miR-187-3p was observed to decrease, facilitating osteogenic differentiation, while the expression of CNR2 increased significantly. These observations suggest that mechanical stress, miR-187-3p, and CNR2 play crucial roles in regulating osteogenic differentiation. Both in vivo and in vitro experiments have confirmed that mechanical stress downregulates miR-187-3p and upregulates CNR2, which leads to the restoration of distal femoral bone mass and enhancement of osteoblast differentiation. Therefore, mechanical stress promotes osteoblasts, resulting in improved osteoporosis through the miR-187-3p/CNR2 signaling pathway. These findings have broad prospect and provide molecular biology guidance for the basic research and clinical application of exercise in the prevention and treatment of PMOP.

The correlation of two bone turnover markers with bone mineral density: a population-based cross-sectional study

OBJECTIVE

Exploring the correlation between bone turnover marks (BTMs) with lumbar BMD in middle-aged populations.

METHODS

The cross-sectional analysis fetched data came from NHANES. The level of serum bone alkaline phosphatase (sBAP) and urinary N-telopeptide (uNTx) were regarded as representative of bone turnover. Lumbar BMD was the outcome of the study. Multivariable linear regression models were utilized to detect the correlation of sBAP and uNTx with Lumbar BMD.

RESULTS

The level of sBAP and uNTx was negatively correlated with lumbar BMD in every multivariable linear regression. For sBAP, this inverse correlation was stable in both men and women (P < 0.01). uNTx indicated a negative association after all relevant covariables were adjusted (P < 0.01). The men group remained the negative correlation in gender subgroup analysis (P < 0.01).

CONCLUSION

This study indicated that the increased level of sBAP and uNTx associated with lumbar BMD decreased among middle-aged adults. This correlation could prompt researchers to explore further the relationship between bone turnover rate and BMD, which may provide information for the early detection of BMD loss and provide a new strategy for clinical practice.

Endocannabinoid signaling and epigenetics modifications in the neurobiology of stress-related disorders

Stress exposure is associated with psychiatric conditions, such as depression, anxiety, and post-traumatic stress disorder (PTSD). It is also a vulnerability factor to developing or reinstating substance use disorder. Stress causes several changes in the neuro-immune-endocrine axis, potentially resulting in prolonged dysfunction and diseases. Changes in several transmitters, including serotonin, dopamine, glutamate, gamma-aminobutyric acid (GABA), glucocorticoids, and cytokines, are associated with psychiatric disorders or behavioral alterations in preclinical studies. Complex and interacting mechanisms make it very difficult to understand the physiopathology of psychiatry conditions; therefore, studying regulatory mechanisms that impact these alterations is a good approach. In the last decades, the impact of stress on biology through epigenetic markers, which directly impact gene expression, is under intense investigation; these mechanisms are associated with behavioral alterations in animal models after stress or drug exposure, for example. The endocannabinoid (eCB) system modulates stress response, reward circuits, and other physiological functions, including hypothalamus-pituitary-adrenal axis activation and immune response. eCBs, for example, act retrogradely at presynaptic neurons, limiting the release of neurotransmitters, a mechanism implicated in the antidepressant and anxiolytic effects after stress. Epigenetic mechanisms can impact the expression of eCB system molecules, which in turn can regulate epigenetic mechanisms. This review will present evidence of how the eCB system and epigenetic mechanisms interact and the consequences of this interaction in modulating behavioral changes after stress exposure in preclinical studies or psychiatric conditions. Moreover, evidence that correlates the involvement of the eCB system and epigenetic mechanisms in drug abuse contexts will be discussed.

Molecular Insights into Epigenetics and Cannabinoid Receptors

The actions of cannabis are mediated by G protein-coupled receptors that are part of an endogenous cannabinoid system (ECS). ECS consists of the naturally occurring ligands N-arachidonylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), their biosynthetic and degradative enzymes, and the CB1 and CB2 cannabinoid receptors. Epigenetics are heritable changes that affect gene expression without changing the DNA sequence, transducing external stimuli in stable alterations of the DNA or chromatin structure. Cannabinoid receptors are crucial candidates for exploring their functions through epigenetic approaches due to their significant roles in health and diseases. Epigenetic changes usually promote alterations in the expression of genes and proteins that can be evaluated by various transcriptomic and proteomic analyses. Despite the exponential growth of new evidence on the critical functions of cannabinoid receptors, much is still unknown regarding the contribution of various genetic and epigenetic factors that regulate cannabinoid receptor gene expression. Recent studies have identified several immediate and long-lasting epigenetic changes, such as DNA methylation, DNA-associated histone proteins, and RNA regulatory networks, in cannabinoid receptor function. Thus, they can offer solutions to many cellular, molecular, and behavioral impairments found after modulation of cannabinoid receptor activities. In this review, we discuss the significant research advances in different epigenetic factors contributing to the regulation of cannabinoid receptors and their functions under both physiological and pathological conditions. Increasing our understanding of the epigenetics of cannabinoid receptors will significantly advance our knowledge and could lead to the identification of novel therapeutic targets and innovative treatment strategies for diseases associated with altered cannabinoid receptor functions.

Identification of Di/Tripeptide(s) With Osteoblasts Proliferation Stimulation Abilities of Yak Bone Collagen by in silico Screening and Molecular Docking

Endothelial protein C receptor (EPCR), cannabinoid receptor 2 (CBR2), and estrogen receptor α (ERα) play vital roles in osteoblasts proliferation. Also, collagen peptides have osteoblasts proliferation stimulation abilities, and di/tri-peptides could be absorbed by the intestine more easily. This study obtained three di/tripeptides with potential osteoblasts proliferation stimulation abilities of yak bone collagen, namely, MGF, CF, and MF, by in silico screening. Results suggested that these three peptides exhibited good absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties. They also had strong affinities with EPCR, CBR2, and ERα, and the total -CDOCKER energy (-CE) values were 150.9469, 113.1835, and 115.3714 kcal/mol, respectively. However, further Cell Counting Kit-8 (CCK-8) assays indicated that only MGF could significantly (P < 0.05) stimulate osteoblasts proliferation at 0.3 mg/ml. At the same time, the proliferating index (PI) of the osteoblasts treated with MGF increased significantly (P < 0.05), and the alkaline phosphatase (ALP) activity decreased highly significantly (P < 0.01). In summary, MGF exhibited the potential to be an effective treatment for osteoporosis.

MicroRNA-149 suppresses osteogenic differentiation of mesenchymal stem cells via inhibition of AKT1-dependent Twist1 phosphorylation

Osteogenic differentiation is a vital process for growth, repair, and remodeling of bones. Accumulating evidence have suggested that microRNAs (miRNAs or miRs) play a crucial role in osteogenic differentiation of mesenchymal stem cells (MSCs). Hence, the current study set out to elucidate the role of miR-149 in osteogenic differentiation of MSCs and the underlying mechanism. First, rat models of bone differentiation were established using the Masquelet-induced membrane technique, and MSCs were isolated. The expression of miR-149 and AKT1 in the rats and cells was detected with RT-qPCR and western blot analysis. The relationships among miR-149, AKT1, and Twist1 were further predicted by online bioinformatics prediction and verified using dual luciferase reporter gene assay. Alteration of miR-149, AKT1, or Twist1 was performed to further explore their effect on osteogenic differentiation of MSCs. miR-149 was poorly expressed in the process of osteogenic differentiation of MSCs, while AKT1 was highly expressed. miR-149 negatively regulated the expression of AKT1, which in turn diminished the protein levels of Twist1 and promoted the phosphorylation levels of Twist1. Lastly, miR-149 acted as an inhibitor of osteogenic differentiation of MSCs, which could be reversed by AKT1. To sum up, miR-149 silencing promoted osteogenic differentiation of MSCs by enhancing Twist1 degradation through AKT1 upregulation, representing a new method for bone repair treatment.

circ-Iqsec1 induces bone marrow-derived mesenchymal stem cell (BMSC) osteogenic differentiation through the miR-187-3p/Satb2 signaling pathway

BACKGROUND

Bone marrow-derived mesenchymal stem cells (BMSCs) are general progenitor cells of osteoblasts and adipocytes and they are characterized as a fundamental mediator for bone formation. The current research studied the molecular mechanisms underlying circRNA-regulated BMSC osteogenic differentiation.

METHODS

Next-generation sequencing (NGS) was employed to study abnormal circRNA and mRNA expression in BMSCs before and after osteogenic differentiation induction. Bioinformatics analysis and luciferase reporting analysis were employed to confirm correlations among miRNA, circRNA, and mRNA. RT-qPCR, ALP staining, and alizarin red staining illustrated the osteogenic differentiation ability of BMSCs.

RESULTS

Data showed that circ-Iqsec1 expression increased during BMSC osteogenic differentiation. circ-Iqsec1 downregulation reduced BMSC osteogenic differentiation ability. The present investigation discovered that Satb2 played a role during BMSC osteogenic differentiation. Satb2 downregulation decreased BMSC osteogenic differentiation ability. Bioinformatics and luciferase data showed that miR-187-3p linked circ-Iqsec1 and Satb2. miR-187-3p downregulation or Satb2 overexpression restored the osteogenic differentiation capability of BMSCs post silencing circ-Iqsec1 in in vivo and in vitro experiments. Satb2 upregulation restored osteogenic differentiation capability of BMSCs post miR-187-3p overexpression.

CONCLUSION

Taken together, our study found that circ-Iqsec1 induced BMSC osteogenic differentiation through the miR-187-3p/Satb2 signaling pathway.

Association of cannabinoid receptor modulation with normal and abnormal skeletal remodelling: A systematic review and meta-analysis of in vitro, in vivo and human studies

To address the inconsistent findings from studies that used different models to explore the role of classical cannabinoid type 1 (CB1) and 2 (CB2) receptors in skeletal remodelling, we searched Medline, Web of Science and Embase for relevant studies from inception to June 23, 2020. We identified 38 in vitro, 34 in vivo and 9 human studies. A meta-analysis of in vitro studies showed that exposure to the inverse-agonists AM251 (mean difference [MD]:-26.75, 95% confidence interval [CI]:-45.36,-8.14, p = 0.005), AM630 (standardised[std.] MD:-3.11, CI:-5.26,-0.97, p = 0.004; SR144528, std.MD:-4.88, CI -7.58,-2.18, p = 0.0004) and CBD (std.MD:-1.39, CI -2.64,-0.14, p = 0.03) is associated with reduced osteoclastogenesis, whereas the endocannabinoid 2-AG (std.MD:2.00, CI:0.11-3.89, p = 0.04) and CB2-selective agonist HU308 (MD:19.38, CI:11.75-27.01, p < 0.00001) were stimulatory. HU308 also enhanced osteoblast differentiation (std.MD:2.22, CI:0.95-3.50, p = 0.0006) and activity (std.MD:2.97, CI:1.22-4.71, p = 0.0008). In models of bone loss, CB1/2 deficiency enhanced peak bone volume (std.MD:3.70, CI:1.77-5.63, p = 0.0002) but reduced bone formation (std.MD:-0.54, CI:-0.90,-0.17, p = 0.004) in female mice. In male rats, CB1/2 deficiency (std.MD:2.31, CI:0.30-4.33, p = 0.02) and AM251 or CBD treatments (std.MD:2.19, CI:0.46-3.93, p = 0.01) enhanced bone volume. CB1/2 deficiency (std.MD:9.78, CI:4.96-14.61, p < 0.0001) and AM251 or AM630 treatments (std.MD:28.19, CI:19.13-37.25, p < 0.0001) were associated with osteoprotection. The CB2-selective agonists JWH133 and 4Q3C enhanced bone volume in arthritic rodents (std.MD:14.45, CI:2.08-26.81, p = 0.02). In human, CB2 SNPs (AA:rs2501431, MD:-0.28, CI:-0.55,-0.01, p = 0.04; CC:rs2501432, MD:-0.29, CI:-0.56,-0.02, p = 0.03) were associated with reduced bone mineral density, however the association of Marijuana use remains unclear. Thus, CB1/2 modulation is associated with altered bone metabolism, however findings are confounded by low study number and heterogenicity of models.

Activation of cannabinoid receptor 2 alleviates glucocorticoid-induced osteonecrosis of femoral head with osteogenesis and maintenance of blood supply

In glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH), downregulated osteogenic ability and damaged blood supply are two key pathogenic mechanisms. Studies suggested that cannabinoid receptor 2 (CB2) is expressed in bone tissue and it plays a positive role in osteogenesis. However, whether CB2 could enhance bone formation and blood supply in GC-induced ONFH remains unknown. In this study, we focused on the effect of CB2 in GC-induced ONFH and possible mechanisms in vitro and in vivo. By using GC-induced ONFH rat model, rat-bone mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) to address the interaction of CB2 in vitro and in vivo, we evaluate the osteogenic and angiogenic effect variation and possible mechanisms. Micro-CT, histological staining, angiography, calcein labeling, Alizarin red staining (ARS), alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) staining, TUNEL staining, migration assay, scratch assay, and tube formation were applied in this study. Our results showed that selective activation of CB2 alleviates GC-induced ONFH. The activation of CB2 strengthened the osteogenic activity of BMSCs under the influence of GCs by promotion of GSK-3β/β-catenin signaling pathway. Furthermore, CB2 promoted HUVECs migration and tube-forming capacities. Our findings indicated that CB2 may serve as a rational new treatment strategy against GC-induced ONFH by osteogenesis activation and maintenance of blood supply.

Contribution of miRNAs and lncRNAs in osteogenesis and related disorders

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

miRNA-187-5p Regulates Osteoblastic Differentiation of Bone Marrow Mesenchymal Stem Cells in Mice by Targeting ICAM1

Osteoporosis (OP) is a common bone metabolic disease, the process of which is fundamentally irreversible. Therefore, the investigation into osteoblastic differentiation of bone marrow mesenchymal stem cells (BMSCs) will provide more clues for OP treatment. In the present study, we found that microRNA-187-5p (miR-187-5p) played a key role on osteoblastic differentiation, which was significantly upregulated during osteogenic differentiation of BMSCs in mice. Moreover, overexpression of miR-187-5p suppressed osteoblastic differentiation of BMSCs through increasing alkaline phosphatase (ALP), matrix mineralization, and levels of Osterix (OSX), and osteopontin (OPN) as well as runt-related transcription factor 2 (Runx2) in vitro. The results in vivo indicated that the upregulation of miR-187-5p enhanced the efficacy of new bone formation in the heterotopic bone formation assay. Luciferase reporter assay and western blot analysis revealed that miR-187-5p was involved in osteogenesis by targeting intracellular adhesion molecule 1 (ICAM-1). Furthermore, ICAM-1 silence inhibited osteoblastic differentiation of BMSCs. Taken together, our results suggested for the first time that miR-187-5p may promote osteogenesis by targeting ICAM-1, and provided a possible therapeutic target for bone metabolic diseases.

lncRNA TUG1 promotes proliferation and differentiation of osteoblasts by regulating the miR-545-3p/CNR2 axis

Osteoblast differentiation is an effective way to promote bone formation. Long non-coding RNA taurine upregulated 1 (TUG1) has been identified as a crucial modulator of multiple biological processes. This study was designed to investigate the function of TUG1 in the proliferation and differentiation of osteoblast precursor cells hFOB1.19. In this study, we found that TUG1 promoted hFOB1.19 cell proliferation, while TUG1 knockdown hindered cell proliferation. TUG1 and cannabinoid receptor 2 (CNR2) were upregulated, while miR-545-3p was down-regulated in hFOB1.19 cells undergoing osteoblastic differentiation. TUG1 induced osteoblast differentiation by increasing alkaline phosphatase (ALP) activity and the expression of osteoblastic differentiation markers. TUG1 was a sponge of miR-545-3p and regulated osteoblastic differentiation by modulating miR-545-3p. Moreover, miR-545-3p directly targeted CNR2 and restored the effect of CNR2 on osteoblastic differentiation. In conclusion, TUG1 accelerated the proliferation and differentiation of osteoblasts by sponging miR-545-3p and increasing CNR2 expression, which might provide a new biomarker for bone diseases.

lncRNA PVT1 aggravates doxorubicin-induced cardiomyocyte apoptosis by targeting the miR-187-3p/AGO1 axis

OBJECTIVES

To investigate the effect of long non-coding (lnc) RNA PVT1 on apoptosis induced by doxorubicin-induced cardiotoxicity.

METHODS

We analyzed the expression levels of lncRNA PVT1, miR-187-3p, using reverse transcription real-time quantitative PCR (RT-qPCR) in doxorubicin-treated cardiomyocytes. The mechanism of lncRNA PVT1 in cardiotoxicity was investigated using cell transfection, CCK-8, flow cytometry, Western blot, and dual-luciferase reporter assays.

RESULTS

Doxorubicin promotes H9c2 apoptosis and increased PVT1 expression in cardiomyocytes. Knockdown of PVT1 attenuated doxorubicin-induced cardiomyocyte apoptosis. We found that miR-187-3p is a direct target of PVT1, and that lncRNA PVT1 adsorbs miR-187-3p by sponge action, reducing miR-187-3p levels. miR-187-3p negatively regulates AGO1, and PVT1 regulates AGO1 expression by targeting miR-187-3p, thereby regulating apoptosis. In addition, we knocked down AGO1 in H9c2 cells transfected with the miR-187-3p inhibitor, and found that it inhibited apoptosis.

CONCLUSION

In doxorubicin-induced cardiomyocyte toxicity, the highly expressed lncRNA PVT1 enhances the expression of AGO1 by sponge adsorption of miR-187-3p. Decreasing the expression of lncRNA PVT1 inhibits the adsorption of miR-187-3p through competing endogenous (ce) RNA, thereby reducing the expression of AGO1 and decreasing the apoptosis of cardiomyocytes.