Vaspin antagonizes high fat-induced bone loss in rats and promotes osteoblastic differentiation in primary rat osteoblasts through Smad-Runx2 signaling pathway

Vaspin facilitates the proliferation and osteogenic differentiation of periodontal ligament stem cells

OBJECTIVE

To investigate whether visceral adipose tissue-derived serine protease inhibitor (vaspin) can alleviate the inhibitory effect of high-glucose (HG) culture on the proliferation and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) and to preliminarily explore the underlying mechanisms.

BACKGROUND

High glucose produces damage to the regeneration of periodontal tissue of PDLSCs. The expression level of vaspin in periodontal tissue is high in periodontitis patients and effectively reduced after initial therapy of periodontal diseases. However, the effect of vaspin on PDLSCs remains unknown.

MATERIALS AND METHODS

PDLSCs were cultured in media augmented with 5.5 or 25.0 mM concentrations of glucose to elucidate the impact and mechanism of vaspin on PDLSCs under high glucose in vitro. Proliferation was measured by Cell Counting Kit-8 (CCK8) assay. Osteogenesis of PDLSCs was assessed by alkaline phosphatase (ALP) staining, ALP activity, and Alizarin Red staining. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB) were used to investigate the osteo-specific markers. Then, the molecular impact of vaspin in the presence/absence of HG on PDLSCs physiology was determined with TGF-β1/Smad signaling pathway as the main focus.

RESULTS

It was revealed that the proliferation and osteogenic differentiation (OD) of PDLSCs under HG was reduced, and by adding vaspin the anti-osteogenic impact of HG was relieved. Moreover, vaspin enhanced TGF-β1/Smad signaling pathway activity. Pretreatment with TGF-β1 inhibitor blocked vaspin-triggered TGF-β1/Smad signal activation and minimized the vaspin-induced protective effect against HG-inhibited growth and OD.

CONCLUSIONS

In summary, vaspin observably reduces HG-mediated inhibition of PDLSCs OD by modulating the TGF-β1/Smad signaling pathway. Vaspin may be a potential therapeutic for periodontal tissue regeneration in diabetic patients.

Adipokines in Rheumatoid Arthritis: Emerging Biomarkers and Therapeutic Targets

Rheumatoid arthritis (RA) is a chronic inflammatory disease manifested by joint involvement, extra-articular manifestations, and general symptoms. Adipose tissue, previously perceived as an inert energy storage organ, has been recognised as a significant contributor to RA pathophysiology. Adipokines modulate immune responses, inflammation, and metabolic pathways in RA. Although most adipokines have a pro-inflammatory and aggravating effect on RA, some could counteract this pathological process. The coexistence of RA and sarcopenic obesity (SO) has gained attention due to its impact on disease severity and outcomes. Sarcopenic obesity further contributes to the inflammatory milieu and metabolic disturbances. Recent research has highlighted the intricate crosstalk between adipose tissue and skeletal muscle, suggesting potential interactions between these tissues in RA. This review summarizes the roles of adipokines in RA, particularly in inflammation, immune modulation, and joint destruction. In addition, it explores the emerging role of adipomyokines, specifically irisin and myostatin, in the pathogenesis of RA and their potential as therapeutic targets. We discuss the therapeutic implications of targeting adipokines and adipomyokines in RA management and highlight the challenges and future directions for research in this field.

Overexpression of microRNA-93-5p and microRNA-374a-5p Suppresses the Osteogenic Differentiation and Mineralization of Human Aortic Valvular Interstitial Cells Through the BMP2/Smad1/5/RUNX2 Signaling Pathway

ABSTRACT

Aortic valve calcification commonly occurs in patients with chronic kidney disease (CKD). However, the regulatory functions of microRNAs (miRNAs/miRs) in the osteogenic differentiation of human aortic valvular interstitial cells (hAVICs) in patients with CKD remain largely unknown. This study aimed to explore the functional role and underlying mechanisms of miR-93-5p and miR-374a-5p in the osteogenic differentiation of hAVICs. For this purpose, hAVICs calcification was induced with high-calcium/high-phosphate medium and the expression levels of miR-93-5p and miR-374a-5p were determined using bioinformatics assay. Alizarin red staining, intracellular calcium content, and alkaline phosphatase activity were used to evaluate calcification. The expression levels of bone morphogenetic protein-2 (BMP2), runt-related transcription factor 2 (Runx2), and phosphorylated (p)-Smad1/5 were detected by luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blot analysis. The results revealed that the expression levels of miR-93-5p and miR-374a-5p were significantly decreased in hAVICs in response to high-calcium/high-phosphate medium. The overexpression of miR-93-5p and miR-374a-5p effectively suppressed the high-calcium/high-phosphate-induced calcification and osteogenic differentiation makers. Mechanistically, the overexpression of miR-93-5p and miR-374a-5p inhibits osteogenic differentiation by regulating the BMP2/Smad1/5/Runx2 signaling pathway. Taken together, this study indicates that miR-93-5p and miR-374a-5p suppress the osteogenic differentiation of hAVICs associated with calcium-phosphate metabolic dyshomeostasis through the inhibition of the BMP2/Smad1/5/Runx2 signaling pathway.

Adipokines regulate mesenchymal stem cell osteogenic differentiation

Mesenchymal stem cells (MSCs) can differentiate into various tissue cell types including bone, adipose, cartilage, and muscle. Among those, osteogenic differentiation of MSCs has been widely explored in many bone tissue engineering studies. Moreover, the conditions and methods of inducing osteogenic differentiation of MSCs are continuously advancing. Recently, with the gradual recognition of adipokines, the research on their involvement in different pathophysiological processes of the body is also deepening including lipid metabolism, inflammation, immune regulation, energy disorders, and bone homeostasis. At the same time, the role of adipokines in the osteogenic differentiation of MSCs has been gradually described more completely. Therefore, this paper reviewed the evidence of the role of adipokines in the osteogenic differentiation of MSCs, emphasizing bone formation and bone regeneration.

Novel Adipokines and Their Role in Bone Metabolism: A Narrative Review

The growing burden of obesity and osteoporosis is a major public health concern. Emerging evidence of the role of adipokines on bone metabolism has led to the discovery of novel adipokines over the last decade. Obesity is recognized as a state of adipose tissue inflammation that adversely affects bone health. Adipokines secreted from white adipose tissue (WAT) and bone marrow adipose tissue (BMAT) exerts endocrine and paracrine effects on the survival and function of osteoblasts and osteoclasts. An increase in marrow fat is implicated in osteoporosis and, hence, it is crucial to understand the complex interplay between adipocytes and bone. The objective of this review is to summarize recent advances in our understanding of the role of different adipokines on bone metabolism.

METHODS

This is a comprehensive review of the literature available in PubMED and Cochrane databases, with an emphasis on the last five years using the keywords.

RESULTS

Leptin has shown some positive effects on bone metabolism; in contrast, both adiponectin and chemerin have consistently shown a negative association with BMD. No significant association was found between resistin and BMD. Novel adipokines such as visfatin, LCN-2, Nesfatin-1, RBP-4, apelin, and vaspin have shown bone-protective and osteoanabolic properties that could be translated into therapeutic targets.

CONCLUSION

New evidence suggests the potential role of novel adipokines as biomarkers to predict osteoporosis risk, and as therapeutic targets for the treatment of osteoporosis.

Circ_CUX1/miR-130b-5p/p300 axis for parathyroid hormone-stimulation of Runx2 activity in rat osteoblasts: A combined bioinformatic and experimental approach

Parathyroid hormone (PTH) regulates the expression of bone remodeling genes by enhancing the activity of Runx2 in osteoblasts. p300, a histone acetyltransferase, acetylated Runx2 to activate the expression of its target genes. PTH stimulated the expression of p300 in rat osteoblastic cells. Increasing studies suggested the potential of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and circular RNAs (circRNAs), in regulating gene expression under both physiological and pathological conditions. In this study, we hypothesized that PTH regulates Runx2 activity via ncRNAs-mediated p300 expression in rat osteoblastic cells. Bioinformatics and experimental approaches identified PTH-upregulation of miR-130b-5p and circ_CUX1 that putatively target p300 and miR-130b-5p, respectively. An antisense-mediated knockdown of circ_CUX1 was performed to determine the sponging activity of circ_CUX1. Knockdown of circ_CUX1 promoted miR-130b-5p activity and reduced p300 expression, resulting in decreased Runx2 acetylation in rat osteoblastic cells. Further, bioinformatics analysis identified the possible signaling pathways that regulate Runx2 activity and osteoblast differentiation via circ_CUX1/miR-130b-5p/p300 axis. The predicted circ_CUX1/miR-130b-5p/p300 axis might pave the way for better diagnostic and therapeutic approaches for bone-related diseases.

Differential bone metabolism and protein expression in mice fed a high-fat diet versus Daurian ground squirrels following natural pre-hibernation fattening

This study compared the effects on bone metabolism and morphology of pathological obesity induced by excessive fat intake in a non-hibernator (mice) versus healthy obesity due to pre-hibernation fattening in a hibernator (ground squirrels). Kunming mice were fed a high-fat diet to provide a model of pathological obesity (OB group). Daurian ground squirrels fattened naturally in their pre-hibernation season (PRE group) were used as a healthy obesity model. Micro-computed tomography (micro-CT) and three-point bending tests were used to determine the microstructure and mechanical properties of bone. Western blots were used to analyze protein expression levels related to bone metabolism (Runt-related transcription factor 2 (RunX2), osteocalcin (OCN), alkaline phosphatase (ALP), osteoprotegerin (OPG), receptor activator of nuclear factor-‍κB ligand (RANKL), cathepsin K, matrix metallopeptidase 9 (MMP9), patched protein homolog 1 (Ptch1), phosphorylated β‍-‍catenin (P‍-‍β‍-‍catenin), and glycogen synthase kinase-3β (GSK-3β)). Compared with controls, there was no obvious bone loss in the OB mice, and the stiffness of the femur was increased significantly. Compared with summer active squirrels, bone formation was enhanced but the mechanical properties did not change in the PRE group squirrels. In OB mice, western blots showed significantly increased expression levels of all proteins except RunX2, OPG, and Ptch1. PRE ground squirrels showed significantly increased expression of most proteins except OCN and Ptch1, which decreased significantly, and P‍-‍β‍-‍catenin and OPG, which did not change. In conclusion, for non-hibernating mice, moderate obesity had a certain protective effect on bones, demonstrating two-way regulation, increasing both bone loss and bone formation. For pre-hibernating ground squirrels, the healthy obesity acquired before hibernation had a positive effect on the microstructure of bones, and also enhanced the expression levels of proteins related to bone formation, bone resorption, and Wnt signaling.

miR-424/322 protects against abdominal aortic aneurysm formation by modulating the Smad2/3/runt-related transcription factor 2 axis

Rupture of abdominal aortic aneurysms (AAAs) is one of the leading causes of sudden death in the elderly population. The osteogenic transcription factor runt-related gene (RUNX) encodes multifunctional mediators of intracellular signal transduction pathways in vascular remodeling and inflammation. We aimed to evaluate the roles of RUNX2 and its putative downstream target miR-424/322 in the modulation of several AAA progression-related key molecules, such as matrix metalloproteinases and vascular endothelial growth factor. In the GEO database, we found that male patients with AAAs had higher RUNX2 expression than did control patients. Several risk factors for aneurysm induced the overexpression of MMPs through RUNX2 transactivation, and this was dependent on Smad2/3 upregulation in human aortic smooth muscle cells. miR-424 was overexpressed through RUNX2 after angiotensin II (AngII) challenge. The administration of siRUNX2 and miR-424 mimics attenuated the activation of the Smad/RUNX2 axis and the overexpression of several AAA progression-related molecules in vitro. Compared to their littermates, miR-322 KO mice were susceptible to AngII-induced AAA, whereas the silencing of RUNX2 and the administration of exogenous miR-322 mimics ameliorated the AngII-induced AAA in ApoE KO mice. Overall, we established the roles of the Smad/RUNX2/miR-424/322 axis in AAA pathogenesis. We demonstrated the therapeutic potentials of miR-424/322 mimics and RUNX2 inhibitor for AAA progression.

Identification of candidate regulators of mandibular bone loss in FcγRIIB-/- Mice

Patients with systemic lupus erythematosus (SLE) have increased inflammatory cytokines, leading to periodontitis and alveolar bone loss. However, the mechanisms driving this phenomenon are still unknown. Here, we have identified novel therapeutic targets for and mediators of lupus-mediated bone loss using RNA-sequencing (RNA-seq) in a FcγRIIB^-/- mouse model of lupus associated osteopenia. A total of 2,710 upregulated and 3,252 downregulated DEGs were identified. The GO and KEGG annotations revealed that osteoclast differentiation, bone mineralization, ossification, and myeloid cell development were downregulated. WikiPathways indicated that Hedgehog, TNFα NF-κB and Notch signaling pathway were also decreased. We identified downregulated targets, Sufu and Serpina12, that have important roles in bone homeostasis. Sufu and Serpina12 were related to Hedgehog signaling proteins, including Gli1, Gli2, Gli3, Ptch1, and Ptch2. Gene knockdown analysis demonstrated that Sufu, and Serpina12 contributed to osteoclastogenesis and osteoblastogenesis, respectively. Osteoclast and osteoblast marker genes were significantly decreased in Sufu-deficient and Serpina12-deficient cells, respectively. Our results suggest that alterations in Hedgehog signaling play an important role in the pathogenesis of osteopenia in FcγRIIB^-/- mice. The novel DEGs and pathways identified in this study provide new insight into the underlying mechanisms of mandibular bone loss during lupus development.

Double-edged effects caused by magnesium ions and alkaline environment regulate bioactivities of magnesium-incorporated silicocarnotite in vitro

Magnesium (Mg) is an important element for its enhanced osteogenic and angiogenic properties in vitro and in vivo, however, the inherent alkalinity is the adverse factor that needs further attention. In order to study the role of alkalinity in regulating osteogenesis and angiogenesis in vitro, magnesium-silicocarnotite [Mg-Ca₅(PO₄)₂SiO₄, Mg-CPS] was designed and fabricated. In this study, Mg-CPS showed better osteogenic and angiogenic properties than CPS within 10 wt.% magnesium oxide (MgO), since the adversity of alkaline condition was covered by the benefits of improved Mg ion concentrations through activating Smad2/3-Runx2 signaling pathway in MC3T3-E1 cells and PI3K-AKT signaling pathway in human umbilical vein endothelial cells in vitro. Besides, provided that MgO was incorporated with 15 wt.% in CPS, the bioactivities had declined due to the environment consisting of higher-concentrated Mg ions, stronger alkalinity and lower Ca/P/Si ions caused. According to the results, it indicated that bioactivities of Mg-CPS in vitro were regulated by the double-edged effects, which were the consequence of Mg ions and alkaline environment combined. Therefore, if MgO is properly incorporated in CPS, the improved bioactivities could cover alkaline adversity, making Mg-CPS bioceramics promising in orthopedic clinical application for its enhancement of osteogenesis and angiogenesis in vitro.

Performance of the Polydopamine-Graphene Oxide Composite Substrate in the Osteogenic Differentiation of Mouse Embryonic Stem Cells

Graphene oxide (GO) is a biocompatible material considered a favorable stem cell culture substrate. In this study, GO was modified with polydopamine (PDA) to facilitate depositing GO onto a tissue culture polystyrene (PT) surface, and the osteogenic performance of the PDA/GO composite in pluripotent embryonic stem cells (ESCs) was investigated. The surface chemistry of the PDA/GO-coated PT surface was analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). A high cell viability of ESCs cultured on the PDA/GO composite-coated surface was initially ensured. Then, the osteogenic differentiation of the ESCs in response to the PDA/GO substrate was assessed by alkaline phosphatase (ALP) activity, intracellular calcium levels, matrix mineralization assay, and evaluation of the mRNA and protein levels of osteogenic factors. The culture of ESCs on the PDA/GO substrate presented higher osteogenic potency than that on the uncoated control surface. ESCs cultured on the PDA/GO substrate expressed significantly higher levels of integrin α5 and β1, as well as bone morphogenetic protein receptor (BMPR) types I and II, compared with the control groups. The phosphorylation of extracellular signal-regulated kinase (ERK)1/2, p38, and c-Jun-N-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs) was observed in ESCs culture on the PDA/GO substrate. Moreover, BMP signal transduction by SMAD1/5/8 phosphorylation was increased more in cells on PDA/GO than in the control. The nuclear translocation of SMAD1/5/8 in cells was also processed in response to the PDA/GO substrate. Blocking activation of the integrin α5/β1, MAPK, or SMAD signaling pathways downregulated the PDA/GO-induced osteogenic differentiation of ESCs. These results suggest that the PDA/GO composite stimulates the osteogenic differentiation of ESCs via the integrin α5/β1, MAPK, and BMPR/SMAD signaling pathways.

The Smad Dependent TGF-β and BMP Signaling Pathway in Bone Remodeling and Therapies

Bone remodeling is a continuous process that maintains the homeostasis of the skeletal system, and it depends on the homeostasis between bone-forming osteoblasts and bone-absorbing osteoclasts. A large number of studies have confirmed that the Smad signaling pathway is essential for the regulation of osteoblastic and osteoclastic differentiation during skeletal development, bone formation and bone homeostasis, suggesting a close relationship between Smad signaling and bone remodeling. It is known that Smads proteins are pivotal intracellular effectors for the members of the transforming growth factor-β (TGF-β) and bone morphogenetic proteins (BMP), acting as transcription factors. Smad mediates the signal transduction in TGF-β and BMP signaling pathway that affects both osteoblast and osteoclast functions, and therefore plays a critical role in the regulation of bone remodeling. Increasing studies have demonstrated that a number of Smad signaling regulators have potential functions in bone remodeling. Therefore, targeting Smad dependent TGF-β and BMP signaling pathway might be a novel and promising therapeutic strategy against osteoporosis. This article aims to review recent advances in this field, summarizing the influence of Smad on osteoblast and osteoclast function, together with Smad signaling regulators in bone remodeling. This will facilitate the understanding of Smad signaling pathway in bone biology and shed new light on the modulation and potential treatment for osteoporosis.

Dysregulation of Circulating miR-24-3p in Children with Obesity and Its Predictive Value for Metabolic Syndrome

INTRODUCTION

Obesity is a major risk factor for metabolic disorders in children. Therefore, it is particularly important to study the abnormal regulation of circulating miR-24-3p in obese children and its predictive value for metabolic syndrome.

METHODS

Serum samples were obtained from children with obesity (n = 45), obese children with metabolic syndrome (n = 52), and healthy controls (n = 50). The expression levels of miR-24-3p were detected by reverse transcription quantitative PCR. The ROC curve was used to evaluate the diagnostic value of miR-24-3p. Pearson's correlation analysis was performed to evaluate the relationship between serum miR-24-3p and different clinical parameters. Logistic regression analysis was used to evaluate the relationship between miR-24-3p and obesity with metabolic syndrome in children.

RESULTS

The expression of miR-24-3p was the highest in obese children with metabolic syndrome. ROC results showed that miR-24-3p had the ability to distinguish healthy individuals from obese children (area under the curve [AUC] = 0.951) and can predict the occurrence of metabolic syndrome for obese children (AUC = 0.890). The expression level of miR-24-3p was positively correlated with body mass index (r = 0.817, p < 0.001), fasting blood glucose (r = 0.798, p < 0.001), triglycerides (r = 0.773, p < 0.001), systolic blood pressure (r = 0.746, p < 0.001), and diastolic blood pressure (r = 0.623, p < 0.001), respectively. Logistic regression analysis showed that miR-24-3p was an independent influence factor for the occurrence of metabolic syndrome in obese children.

DISCUSSION/CONCLUSION

MiR-24-3p is a potential noninvasive marker for children with obesity and has predictive value for the occurrence of metabolic syndrome.

Adipokines: New Potential Therapeutic Target for Obesity and Metabolic, Rheumatic, and Cardiovascular Diseases

Besides its role as an energy storage organ, adipose tissue can be viewed as a dynamic and complex endocrine organ, which produces and secretes several adipokines, including hormones, cytokines, extracellular matrix (ECM) proteins, and growth and vasoactive factors. A wide body of evidence showed that adipokines play a critical role in various biological and physiological functions, among which feeding modulation, inflammatory and immune function, glucose and lipid metabolism, and blood pressure control. The aim of this review is to summarize the effects of several adipokines, including leptin, diponectin, resistin, chemerin, lipocalin-2 (LCN2), vaspin, omentin, follistatin-like 1 (FSTL1), secreted protein acidic and rich in cysteine (SPARC), secreted frizzled-related protein 5 (SFRP5), C1q/TNF-related proteins (CTRPs), family with sequence similarity to 19 member A5 (FAM19A5), wingless-type inducible signaling pathway protein-1 (WISP1), progranulin (PGRN), nesfatin-1 (nesfatin), visfatin/PBEF/NAMPT, apelin, retinol binding protein 4 (RPB4), and plasminogen activator inhibitor-1 (PAI-1) in the regulation of insulin resistance and vascular function, as well as many aspects of inflammation and immunity and their potential role in managing obesity-associated diseases, including metabolic, osteoarticular, and cardiovascular diseases.

Circulating Levels of Visceral Adipose Tissue-Derived Serine Protease Inhibitor (Vaspin) Appear as a Marker of Musculoskeletal Pain Disability

Musculoskeletal pain (MSP), specifically low back pain (LBP), is often associated with several adipose tissue-derived cytokines (adipokines) and body composition, but their correlations with the LBP-related disability/severity phenotypes remain poorly understood. In this cross-sectional study, two self-reported validated questionnaires were used to collect back pain and disability data in an ethnically homogeneous family-based population sample (N = 1078). Plasma levels of relatively new adipokines, vaspin and adipsin, were detected by ELISA. Body composition parameters, including fat, skeletal muscle mass, extracellular water (ECW), and others were assessed through bioelectrical impedance analysis (BIA) technology. Statistical analysis was conducted, accounting for the familial composition of the sample. The multiple regression analyses with four LBP-related phenotypes as dependent variables consistently showed, for the first time, the significant associations with vaspin levels, regardless of other covariates. The odds ratios (OR)/SD ranged between 1.24 (95%CI = 1.03-1.50) and 1.33 (95%CI = 1.07-1.64), depending on the LBP phenotype. Among the tested body composition covariates, only ECW levels displayed consistent and highly significant associations with all tested LBP phenotypes (OR from 1.43, 95%CI = 1.14-1.79 to 1.68, 95%CI = 1.26-2.24). The results clearly suggest that circulating concentrations of vaspin and ECW levels could serve as biomarkers of MSP/LBP severity and complications.

Plasma vaspin is an effective biomarker for evaluation of future cardiovascular events in patients with chest pain: a 5-year retrospective observational study

Background

Our previous study showed that visceral adipose tissue-derived serpin (vaspin) was an independent predictor of coronary artery disease (CAD). Further, plasma vaspin levels in patients with unstable angina pectoris were lower than those in patients with stable angina pectoris. In this study, we investigated the prognostic relevance of plasma vaspin levels in patients with CAD and non-CAD.

Methods

It was a retrospective observational study. A total of 197 patients with chest pain were enrolled, of which 88 patients with CAD and 109 patients with non-CAD were confirmed by angiography. Plasma vaspin levels and clinical parameters were measured at baseline. Incidence of major adverse cardiac event (MACE) was determined on follow-up.

Results

One hundred eighty-nine patients were successfully followed up for 5 years, of which 63 patients experienced MACEs. Patients with low vaspin levels (<0.385 ng/mL) experienced a higher incidence of MACE as compared to patients with high vaspin levels (>0.385 ng/mL) (42.55% vs. 24.21%, respectively; P=0.007). In both CAD and non-CAD groups, patients with high vaspin levels showed improvement in left ventricular ejection fraction. Kaplan Meier survival curves showed that patients with low vaspin levels had an obviously higher timing of incidence of MACE in the whole population (P=0.006) and in the non-CAD subgroup (P=0.009); however, the trend was not significant in the CAD subgroup. On multivariate analyses, plasma vaspin level was found to be an independent predictor of MACE, particularly in the non-CAD group.

Conclusions

Plasma vaspin may be a useful biomarker for prediction of MACE in patients with chest pain.

Overexpression of microRNA-141 inhibits osteoporosis in the jawbones of ovariectomized rats by regulating the Wnt/β-catenin pathway

OBJECTIVE

This work was aimed to investigate the effect of microRNA-141 (miR-141) overexpression in the jawbones of ovariectomized-induced osteoporosis rats and investigate the role of miR-141 in the Wnt/β-catenin pathway.

METHODS

Twenty-four female rats were randomly divided into the sham group, ovariectomized osteoporosis group (OP), miR-141 agonist group (miR-141), and miR-141 scramble group (Scramble). Bone mineral density (BMD) and pathological changes of the jaw were detected. Serum receptor activator of nuclear factor-B ligand (RANKL), osteoprotegerin, tartrate-resistant acid phosphatase (TRAP), and bone gla protein (BGP) levels were tested by ELISA. The expression of Runt-related transcription factor 2 (Runx2), and Osterix measured by immunohistochemistry and the expression of Wnt, β-catenin, and Dickkopf1 (DKK1) proteins was measured by Western blot. Furhter, the Wnt agonist DKK2-C2, Wnt inhibitor Endostar were used to verify the effect of miR-141 overexpression on the Wnt/β-catenin pathway.

RESULT

Compared with the OP group, the content of osteoprotegerin increased while the levels of RANKL, BGP, TRAP decreased in the miR-141 and DKK2-C2 groups (p < 0.05). The levels of Runx2 and Osterix increased significantly in the miR-141 and DKK2-C2 groups when compared to the OP group (p < 0.05). Interestingly, the protein expression of Wnt and β-catenin increased while DKK1 was remarkably down-regulated in the miR-141 and DKK2-C2 groups when compared to the OP group (p < 0.05). In contrast to the miR-141 group, the above results were reversed after treatment with the Endostar (p < 0.05).

CONCLUSION

Overexpression of miR-141 could inhibit the osteoporosis of jawbones in ovariectomized rats by activating the Wnt/β-catenin pathway.