Role of sclerostin in the occurrence and development of uveal melanoma and its biological mechanism / 中华实验眼科杂志

Objective:To investigate the effects of sclerostin (SOST) and WNT/CTNNB1 signaling pathway on the cell cycle, migration and invasion of human uveal melanoma (UM) cells and its related mechanism.Methods:UM tissues from 20 cases of epithelioid UM and 16 cases of spindle cell type UM were collected.The contents of SOST, Wnt-1 and Catenin beta-1 proteins in the collected tissues were detected by immunohistochemical staining.Three human UM tissue derived cell lines OCM-1 (primary spindle cell type), Mum-2B (metastatic epithelioid) and Mum-2C (metastatic spindle cell type) were selected and divided into three groups, blank control group not transfected, empty vector group transfected with SOST negative control vector and SOST siRNA group transfected with SOST siRNA.After 24-hour transfection, the mRNA and protein expression levels of SOST, CTNNB1, WNT protein family 1 (WNT1), CCND1, matrix metalloproteinase (MMP)2 and MMP9 were detected by real-time fluorescence quantitative PCR and Western blot, respectively.The invasion and migration ability of the transfected cells were measured by transwell method, and the cell cycle distribution was detected by flow cytometry.Another 9 female BALB/c nude mice were selected and randomized into OCM-1 group, OCM-1 empty vector group and SOST shRNA group, inoculated with OCM-1 without lentivirus infection, OCM-1 with blank lentivirus infection and OCM-1 with SOST shRNA lentivirus infection, respectively.Six weeks after inoculation, the in situ formation of tumor was observed.The interaction between SOST and low density lipoprotein receptor related protein(LRP)-5/6 in OCM-1 cells was explored by co-immunoprecipitation assay.The study protocol was approved by the Ethics Committee of Tianjin Medical University Eye Hospital (2018KY[L]-20).Results:Immunohistochemical staining results showed that the SOST expression level was higher and the expression levels of Wnt-1 and Catenin beta-1 were lower in spindle cell type UM tissues than in epithelioid UM tissues, and the differences were all statistically significant (all at P<0.01). The real-time fluorescence quantitative PCR results showed that the relative expression of SOST mRNA was significantly lower and the relative expressions of CCND1, WNT1 and MMP9 mRNA were significantly higher in SOST siRNA groups than in corresponding empty vector groups in the three cell lines (all at P<0.05). In OCM-1 and Mum-2C cell lines, the relative expressions of CTNNB1 mRNA were significantly higher in SOST siRNA groups than in empty vector groups (all at P<0.01). Western blot results showed that the relative expression of SOST protein was significantly lower and the relative expressions of Wnt-1, Catenin beta-1, cyclin-D1, MMP2 and MMP9 proteins were significantly higher in SOST siRNA groups than in empty vector groups (all at P<0.01). Transwell assay showed that the cell invasion and migration ability of SOST siRNA group was significantly higher than that of blank control group and empty vector group in the three cell lines (all at P<0.01). Flow cytometry showed that the proportion of G1-phase cells and the G1/S-phase ratio were significantly lower in SOST siRNA group than in blank control groups and empty vector groups (all at P<0.01). The eyeball volume of OCM-1 group, OCM-1 empty vector group and SOST shRNA group was (42.7±4.6), (49.0±22.9) and (135.2±32.7)mm 3, respectively, showing a significant overall difference ( F=19.963, P<0.01). The eyeball volume of SOST shRNA group was larger than that of OCM-1 group and OCM-1 empty vector group, and the differences were statistically significant (both at P<0.05). Co-immunoprecipitation results showed that SOST could interact with LRP-5 and LRP-6 by binding to them, respectively. Conclusions:Silencing SOST can promote the invasion and migration of UM cells, and increase the proportion of UM cells in the division phase.Silencing SOST can promote tumor growth in eyes of nude mice.SOST may play this function by interacting with the membrane receptor LRP-5/LRP-6 and then regulating the WNT/CTNNB1 signal pathway.

Comparison of serum levels of sclerostin, Dickkopf-related protein 1, and irisin in patients with type 1 and type 2 diabetes / 中华内分泌代谢杂志

Objective:Both type 1 diabetes and type 2 diabetes are associated with abnormal bone metabolism, but they have different pathogenic mechanisms. Sclerostin(SOST), Dickkopf-related protein 1(DKK-1), and irisin are newly discovered factors involved in the regulation of bone metabolism. This study aims to compare the differences in serum levels of SOST, DKK-1, and irisin between patients with type 1 diabetes and type 2 diabetes.Methods:This cross-sectional study included 101 patients with type 1 diabetes who visited the Endocrinology Department of Peking Union Medical College Hospital from 2017 to 2019, as well as 55 patients with type 2 diabetes and 59 individuals with normal glucose tolerance who were confirmed through an oral glucose tolerance test as part of the Beijing Changping Community Type 2 Diabetes Management Program from 2014 to 2015. Enzyme-linked immunosorbent assay(ELISA) was used to measure the levels of SOST, DKK-1, and irisin.Results:There were more female participants than male participants, with an average age of 49 years. The group with type 1 diabetes had a longer duration of illness( P<0.001) and higher HbA 1C levels( P<0.001) compared to the group with type 2 diabetes, and there was no statistical difference in age between the two groups. Both the type 1 diabetes and type 2 diabetes groups had lower levels of serum procollagen type 1 N-terminal propeptide(P1NP) compared to the control group [(8 579±400)pg/mL, (7 268±552)pg/mL vs(10 051±618)pg/mL, P=0.039, P=0.001]; But the β isomer of C-terminal cross-linking telopeptide of type 1 collagen(β-CTX) showed no statistical difference compared to the control group. Patients with type 1 diabetes and type 2 diabetes had higher SOST than controls [(129.7±6.8)pg/mL, (104.8±6.8)pg/mL vs(85.9±5.3)pg/mL, P<0.001, P=0.030], the differences between the type 1 diabetes group and the control group lost statistical significance after adjusting for factors such as fasting blood glucose and lipid levels. There was no significant difference in SOST between type 1 diabetes and type 2 diabetes groups. There was no significant difference in DKK-1 among three groups, but DKK-1 in type 1 diabetes group was lower or tended to be lower than that in type 2 diabetes group. Serum irisin in patients with type 1 diabetes was higher than that in controls and patients with type 2 diabetes[(16.6±0.7)ng/mL vs (9.6±0.6)ng/mL, (9.8±0.6)ng/mL, both P<0.001], but there was no significant difference in irisin level between type 2 diabetes and controls. Conclusions:Patients with both type 1 and type 2 diabetes showed inhibition of the bone formation marker P1NP, while the bone resorption marker β-CTX did not significantly change. SOST levels were elevated or showed an increasing trend in both type 1 and type 2 diabetes patients, which may be related to the inhibition of bone formation. Additionally, type 1 diabetes patients had increased levels of irisin, which may be involved in abnormal bone turnover.

The correlation analysis between plasma sclerostin levels and bone turnover markers and inflammation factors in hemodialysis patients / 中国医师进修杂志

Objective:To explore the correlation between plasma sclerostin (SOST) and bone turnover markers and inflammatory factors in hemodialysis patients.Methods:One hundred and eight patients admitted to Changsha Central Hospital Affiliated to Nanhua University from January 2018 to May 2019 were selected. The levels of plasma SOST at admission and at 3, 6 and 12 months of dialysis were determined by enzyme-linked immunosorbent assay. They were divided into low- SOSTgroup (56 cases) and high- SOSTgroup (52 cases) based on the mean value of SOST. The levels of serum bone turnover markers β-Ⅰ collagen carboxy-terminal peptide (β-CTX) and osteocalcin (OC), propeptide of type Ⅰ procollagen (PINP), full parathyroid hormone (iPTH), N-terminal osteocalcin (N-MID-OC), inflammatory factors interleukin-1β (IL-1β), interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) were compared between the two groups, abdominal aortic calcification (ACC) score was performed, and Pearson linear correlation analysis was used to analyze the relationship between SOST level of hemodialysis patients and bone turnover markers, inflammatory factors and ACC scores.Results:The baseline levels of β-CTX, OC, PINP, iPTH, and N-MID-OC in the low- SOST group were higher than those in the high- SOST group: (976.03 ± 205.27) ng/L vs. (781.34 ± 150.45) ng/L, (175.31 ± 50.49) ng/L vs. (125.75 ± 40.17) ng/L, (321.45 ± 82.14) μg/L vs. (259.41 ± 75.36) μg/L, (345.26 ± 102.65) ng/L vs. (198.52 ± 45.71) ng/L, (19.96 ± 5.01) μg/L vs. (17.41 ± 4.23) μg/L, the differences were statistically significant ( P<0.05). The baseline levels of IL-1β, IL-6, CRP, TNF-α and ACC scores in the low- SOST group were higher than those in the high- SOST group: (19.31 ± 6.01) ng/L vs. (15.23 ± 4.75) ng/L, (76.85 ± 20.34) ng/L vs. (57.98 ± 15.02) ng/L, (8.15 ± 2.36) mg/L vs. (7.23 ± 1.79) mg/L, (178.37 ± 55.52) ng/L vs. (157.42 ± 10.15) ng/L, (5.96 ± 1.78) scores vs. (5.11 ± 1.15) scores, the differences were statistically significant ( P<0.05). After treated for 3, 6 and 12 months, the levels of β-CTX, OC, PINP, iPTH, N-MIC-OC in hemodialysis patients were increased, the level of SOST was decreased, the levels of IL-1β, IL-6, CRP, TNF-α increased and ACC scores were increased, the differences were statistically significant ( P<0.05). The Pearson linear correlation analysis showed that SOST level and bone turnover markers β-CTX ( r = -0.465, P<0.001), OC( r = -0.498, P<0.001), PINP( r = -0.511, P<0.001), iPTH ( r = -0.396, P = 0.012), N-MID -OC ( r = -0.323, P = 0.031) and inflammatory factors IL-1β( r = -0.305, P = 0.046), IL-6( r = -0.318, P = 0.041), CRP( r = -0.327, P = 0.034) and TNF-α( r = -0.378, P = 0.024) in hemodialysis patients were negatively correlated, and negatively correlated with abdominal aortic calcification scores ( r = -0.301, P = 0.048). Conclusions:Plasma SOST level in hemodialysis patients is lower, which is negatively correlated with bone turnover markers, inflammatory factors, and calcification scores. Low SOST level can induce vascular calcification by mediating bone metabolism disorders and aggravating the body′s inflammatory response, and increase the risk of hemodialysis vascular calcification.

Drug discovery of sclerostin inhibitors

Sclerostin, a protein secreted from osteocytes, negatively regulates the WNT signaling pathway by binding to the LRP5/6 co-receptors and further inhibits bone formation and promotes bone resorption. Sclerostin contributes to musculoskeletal system-related diseases, making it a promising therapeutic target for the treatment of WNT-related bone diseases. Additionally, emerging evidence indicates that sclerostin contributes to the development of cancers, obesity, and diabetes, suggesting that it may be a promising therapeutic target for these diseases. Notably, cardiovascular diseases are related to the protective role of sclerostin. In this review, we summarize three distinct types of inhibitors targeting sclerostin, monoclonal antibodies, aptamers, and small-molecule inhibitors, from which monoclonal antibodies have been developed. As the first-in-class sclerostin inhibitor approved by the U.S. FDA, the monoclonal antibody romosozumab has demonstrated excellent effectiveness in the treatment of postmenopausal osteoporosis; however, it conferred high cardiovascular risk in clinical trials. Furthermore, romosozumab could only be administered by injection, which may cause compliance issues for patients who prefer oral therapy. Considering these above safety and compliance concerns, we therefore present relevant discussion and offer perspectives on the development of next-generation sclerostin inhibitors by following several ways, such as concomitant medication, artificial intelligence-based strategy, druggable modification, and bispecific inhibitors strategy.

Liquid chromatography-mass spectrometry method for the quantification of an anti-sclerostin monoclonal antibody in cynomolgus monkey serum / 药物分析学报

Liquid chromatography tandem mass spectrometry (LC-MS/MS) has gradually become a promising alternative to ligand binding assay for the bioanalysis of biotherapeutic molecules,due to its rapid method development and high accuracy.In this study,we established a new LC-MS/MS method for the determination of the anti-sclerostin monoclonal antibody (SHR-1222) in cynomolgus monkey serum,and compared it to a previous electrochemiluminescence method.The antibody was quantified by detecting the surrogate peptide obtained by trypsin digestion.The surrogate peptide was carefully selected by investigating its uniqueness,stability and MS response.The quantitative range of the pro-posed method was 2.00-500 μg/mL,and this verified method was successfully applied to the tox-icokinetic assessment of SHR-1222 in cynomolgus monkey serum.It was found that the concentrations of SHR-1222 in cynomolgus monkeys displayed an excellent agreement between the LC-MS/MS and electrochemiluminescence methods (ratios of drug exposure,0.8-1.0).Notably,two monkeys in the 60 mg/kg dose group had abnormal profiles with a low detection value of SHR-1222 in their individual sample.Combining the high-level anti-drug antibodies (ADAs) in these samples and the consistent quantitative results of the two methods,we found that the decreased concentration of SHR-1222 was due to the accelerated clearance mediated by ADAs rather than the interference of ADAs to the detection platform.Taken together,we successfully developed an accurate,efficient and cost-effective LC-MS/MS method for the quantification of SHR-1222 in serum samples,which could serve as a powerful tool to improve the preclinical development of antibody drugs.

Impact of microRNA / 中南大学学报(医学版)

OBJECTIVES@#To explore the molecular mechanism for thyroid cancer metastasis via analyzing the role of microRNA (miR)-21-5p and its target gene recombinant sclerostin domain containing protein 1 (SOSTDC1) in thyroid cancer.@*METHODS@#The target miR-21-5p was screened through bioinformatics analysis and cell verification, and the thyroid cancer cell lines was transfected with miR-21-5p inhibitor. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, flow cytometry, and cell scratch test were used to detect the proliferation, apoptosis and migration of thyroid cancer cells in the miR-21-5p inhibitor group and the inhibitor control group, respectively. The luciferase report experiment was used to verify the relationship between miR-21-5p and SOSTDC1, Western blotting was used to detect the expression levels and phosphorylation levels of SOSTDC1,phosphatidylinositol 3 kinase (PI3K), protein kinase B (Akt) and mitogen-activated protein kinases (MAPK), extracellular regulated protein kinases (ERK) in thyroid cancer cells.@*RESULTS@#MiR-21-5p was significantly increased in thyroid cancer cells,which was negatively correlated with SOSTDC1 (@*CONCLUSIONS@#MiR-21-5p in thyroid cancer cells can target the expression of SOSTDC1 and affect the activities of PI3K/Akt and MAPK/ERK, thereby inhibiting the apoptosis of thyroid cancer cells and promoting cell proliferation and migration.

Research progress on the relationship between osteocytes and periodontitis / 口腔疾病防治

@#Osteocytes, which develop from osteoblasts, are recognized as the main cells embedded in mature bone tissue. The traditional notion is that osteocytes exclusively play a structural role, however, with the development of related research in recent years, the role of osteocytes in bone metabolism has been explored. Periodontitis is a chronic inflammatory disease initiated by plaque biofilm, and is the main cause of adult tooth loss. Clinically, periodontitis primarily manifests as attachment loss, bleeding on probing and other symptoms. Alveolar bone resorption is the most characteristic pathological change. Current research demonstrated that osteocytes sense mechanical stress, participate in bone remodeling, regulate mineral balance, and participate in endocrine function. Thus, these cells play an important role in bone homeostasis and systemic metabolic balance. Osteocytes are actively involved in the development of periodontitis through the high expression of receptor activator of nuclear factor kappa B ligand (RANKL), secretion of sclerostin, and effect on apoptosis, senescence and autophagy. In the future, the detection of bone cell metabolism-related products will have certain application prospects for the clinical evaluation of periodontitis prevention and treatment. Therefore, this paper reviewed the role of osteocytes in bone homeostasis and the relationship between osteocytes and periodontitis, to provide new ideas for the prevention and treatment of periodontitis.

Expression of sclerostin in alveolar bone remodeling of ovariectomized rats / 口腔疾病防治

Objective@# To investigate the expression and distribution of sclerostin in the alveolar bone of rat in the absence of estrogen, and to provide evidence for the analysis of the histological correlation between sclerostin and alveolar bone remodeling in rats. @*Methods @#The experimental subjects of this study were 32 8-week-old female Wistar rats. Among them, 16 rats were ovariectomized (OVX), and 16 rats were subjected to a sham operation (Sham). These rats were sacrificed 1, 2, 3, and 4 weeks after the operation, and the mandibles were removed and embedded. The mesial and distal sections of the rat,s mandibular first molars were selected and stained with anti-tartrate phosphatase (TRAP), sclerostin immunostaining, multiple immunostainings, RANKL and TRAP double staining, and silver-plated multiple staining. @*Results @#As the postoperative time in rats increased, the TRAP-positive osteoclasts counts in the OVX group in the interalveolar septum of mandibular first molar increased significantly, and statistical difference was noted between the groups (P ＜ 0.05). The OVX 2w, 3w, and 4w groups exhibited more TRAP-positive osteoclasts compared with the Sham group at the corresponding time point, and the results were statistically different (P ＜ 0.05). Sclerostin immunostaining revealed that the proportion of positive bone cells in the mesial side of the periodontal ligament area of mandibular first molar in the OVX group gradually decreased. Statistical differences were noted between the OVX 3w group and the OVX 4w group as well as the OVX 1w group and, the OVX 2w group (P ＜ 0.05). In the comparison between the area near the periodontal ligament and the central area of the alveolar bone septum of the mandibular first molar in the same group, the positive expression ratio of sclerostin in the OVX 3w and OVX 4w groups in the area near the periodontal ligament was reduced compared with that in the central area of the alveolar bone septum. The results were statistically significant (P ＜ 0.05). A larger number of osteoblasts was noted around the osteoclasts in the OVX 4w group compared with the Sham 4w group based on ALP/ TRAP /sclerostin multiple staining, whereas less sclerostin-positive osteoblasts were noted in the OVX 4w group. Sclerostin/TRAP/silver plating staining showed that the bone tubules around the sclerostin positive bone cells mostly exhibited a parallel and neat arrangement, and the bone tubules around sclerostin negative bone cells were more irregular and disorderly arranged in the OVX 4w group@*Conclusion@#Sclerostin protein is involved in alveolar bone remodeling in estrogen-deficient rats.

Pulsed electromagnetic fields stimulation combined with sclerostin antibody improves bone metabolism and bone microstructure in postmenopausal osteoporosis rabbits / 中国组织工程研究

BACKGROUND: Both pulsed electromagnetic fields (PEMF) stimulation and sclerostin antibody (Scl-Ab) have good effects on the bone metabolism of ovariectomized (OVX) New Zealand rabbits, but research on the combined intervention of PEMF and Scl-Ab in the OVX rabbits is rarely reported. OBJECTIVE: To explore the effect of PEMF combined with Scl-Ab on postmenopausal osteoporosis and to explore the therapeutic value for osteoporosis. METHODS: An animal model of postmenopausal osteoporosis was made in New Zealand white rabbits after ovariectomy. The experimental animals were randomly divided into OVX control group, PEMF group, Scl-Ab group and PEMF+Scl-Ab group, with 10 rats in each group. On the 1st day after surgery, the PEMF group was given PEMF magnetic therapy once a day; the Scl-Ab group was given subcutaneous injection of Scl-Ab twice a week; the PEMF+Scl-Ab group received PEMF magnetic therapy once a day, five times a week, and Scl-Ab subcutaneous injections twice a week; the OVX group was injected subcutaneously with the same dose of normal saline twice a week for 8 weeks. After 8 weeks of treatment, bone metabolism index, bone mineral density, and MicroCT bone microstructure parameters were detected. All animal procedures were approved by the Department of Experimental Animal Science, Fudan University (approval No. 20171263A193). RESULTS AND CONCLUSION: Bone mineral density was significantly decreased in the New Zealand white rabbits after 6 months of OVX, suggesting that the osteoporosis model was successfully established. Compared with the OVX group, the bone mineral density of the L3 vertebral body in the PEMF group, the Scl-Ab group and the PEMF+Scl-Ab group increased significantly (P < 0.05). Compared with the OVX group, serum bone-specific alkaline phosphatase levels were significantly higher, and serum tartrate-resistant acid phosphatase 5b levels were significantly lower in the PEMF group, the Scl-Ab group and the PEMF+Scl-Ab group. The serum tartrate-resistant acid phosphatase 5b level in the PEMF+Scl-Ab group was significantly lower than that in the PEMF group and the Scl-Ab group. The bone metabolism index and bone microstructural parameters (bone volume fraction, trabecular thickness, trabecular number, and trabecular separation) of the PEMF+Scl-Ab group were significantly better than those of the PEMF group and the Scl-Ab group (all P < 0.05). These findings indicate that the combination of Scl-Ab and PEMF can enhance bone mineral density and improve bone metabolism and bone microstructure in postmenopausal osteoporosis New Zealand white rabbits.

Effect of sclerostin on the functions and related mechanisms of cementoblasts under mechanical stress / 华西口腔医学杂志

OBJECTIVE@#The purpose of this study is to investigate the potential effects of sclerostin (SOST) on the biological funtions and related mechanisms of cementoblasts under mechanical stress.@*METHODS@#OCCM-30 cells were treated with varying doses of SOST (0, 25, 50, and 100 ng·mL⁻¹) and were loaded with uniaxial compressive stress (2 000 μ strain with a frequency of 0.5 Hz) for six hours. Western blot was utilized to detect the expressions of β-catenin, p-smad1/5/8, and smad1/5/8 proteins. Alkaline phosphatase (ALP) activity was determined, and reverse transcription polymerase chain reaction was used to measure the expressions of runt-related transcription factor 2 (Runx-2), osteocalcin (OCN), bone sialoproteins (BSP), receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) mRNA.@*RESULTS@#The expression of p-smad
1/5/8 was significantly downregulated with increasing SOST. β-catenin and smad1/5/8 exhibited no difference. ALP activity decreased under mechanical compressive stress with increasing SOST concentrations. Runx-2 expression was reduced with increasing SOST concentrations, and a similar trend was observed for the BSP and OCN expressions. When the SOST concentration was enhanced, RANKL expression gradually increased, whereas the expression of OPG decreased.@*CONCLUSIONS@#Under mechanical comprehensive stress, SOST can adjust the bone morphogenetic protein (BMP) /smad signal pathway. Osteosclerosis inhibits the mineralization of cementoblasts under mechanical compressive stress, which may be achieved by inhibiting the expressions of osteogenesis factors (Runx2, OCN, BSP, and others) and by promoting the ratio of cementoclast-related factors (RANKL/OPG) through BMP signal pathways.

Gingival crevicular fluid levels of sclerostin in chronic periodontitis and healthy subjects

OBJECTIVES: Chronic periodontitis is a common inflammatory disease of the oral cavity that causes destruction of periodontal tissues and bone around the teeth. Sclerostin is a protein encoded by the SOST gene. In this study, gingival crevicular fluid (GCF) levels of sclerostin in patients with chronic periodontitis were compared with those of healthy subjects. MATERIALS AND METHODS: In this case-control study, a total of 40 subjects were enrolled and divided into the healthy group (n=23) and chronic periodontitis group (n=17). GCF samples were collected, and the concentration of sclerostin was evaluated using enzyme-linked immunosorbent assay. Comparison of significance between groups was assessed using Mann-Whitney U test. RESULTS: Sclerostin concentration was significantly higher in the chronic periodontitis group compared with the healthy group (P < 0.005). CONCLUSION: Despite the limitations of this study, sclerostin can be a possible marker for assessment of periodontal health status.

Skeletal Fragility in Type 2 Diabetes Mellitus

Type 2 diabetes (T2D) is associated with an increased risk of fracture, which has been reported in several epidemiological studies. However, bone mineral density in T2D is increased and underestimates the fracture risk. Common risk factors for fracture do not fully explain the increased fracture risk observed in patients with T2D. We propose that the pathogenesis of increased fracture risk in T2D is due to low bone turnover caused by osteocyte dysfunction resulting in bone microcracks and fractures. Increased levels of sclerostin may mediate the low bone turnover and may be a novel marker of increased fracture risk, although further research is needed. An impaired incretin response in T2D may also affect bone turnover. Accumulation of advanced glycosylation endproducts may also impair bone strength. Concerning antidiabetic medication, the glitazones are detrimental to bone health and associated with increased fracture risk, and the sulphonylureas may increase fracture risk by causing hypoglycemia. So far, the results on the effect of other antidiabetics are ambiguous. No specific guideline for the management of bone disease in T2D is available and current evidence on the effects of antiosteoporotic medication in T2D is sparse. The aim of this review is to collate current evidence of the pathogenesis, detection and treatment of diabetic bone disease.

Strontium ranelate inhibits wear particle-induced aseptic loosening in mice

The imbalance between bone formation and osteolysis plays a key role in the pathogenesis of aseptic loosening. Strontium ranelate (SR) can promote bone formation and inhibit osteolysis. The aim of this study was to explore the role and mechanism of SR in aseptic loosening induced by wear particles. Twenty wild-type (WT) female C57BL/6j mice and 20 sclerostin-/- female C57BL/6j mice were used in this study. Mice were randomly divided into four groups: WT control group, WT SR group, knockout (KO) control group, and KO SR group. We found that SR enhanced the secretion of osteocalcin (0.72±0.007 in WT control group, 0.98±0.010 in WT SR group, P=0.000), Runx2 (0.34±0.005 in WT control group, 0.47±0.010 in WT SR group, P=0.000), β-catenin (1.04±0.05 in WT control group, 1.22±0.02 in WT SR group, P=0.000), and osteoprotegerin (OPG) (0.59±0.03 in WT control group, 0.90±0.02 in WT SR group, P=0.000). SR significantly decreased the level of receptor activator for nuclear factor-κB ligand (RANKL) (1.78±0.08 in WT control group, 1.37±0.06 in WT SR group, P=0.000) and improved the protein ratio of OPG/RANKL, but these effects were not observed in sclerostin-/- mice. Our findings demonstrated that SR enhanced bone formation and inhibited bone resorption in a wear particle-mediated osteolysis model in wild-type mice, and this effect relied mainly on the down-regulation of sclerostin levels to ameliorate the inhibition of the canonical Wnt pathway.

Effect of ERRα in silencing DKK1 and SOST recombinant adenovirus vector-transfected MG63 Cells and bone-related proteins / 医学研究生学报

Objective WNT signaling pathway plays an important role in the formation, differentiation and maturation of bone cells, it is a classical intracellular signaling pathway involved in bone metabolism. DKK1 and Sost play a negative regulatory role in regulating bone mass and osteoblast differentiation, and are negative regulators of WNT signaling pathway. Estrogen-related receptor alpha (ERRα) regulates the functional activity of osteoblasts. The aim of study was to investigate the effect of ERRα on the transfection of MG63 cells and related proteins by the WNT signaling pathway inhibitor Dickkopf (DKK)1 and sclerostin (SOST) adenovirus vectors.Methods The cultured MG63 cells were divided into blank control group, silencing DKK1 group, silencing SOST group, silencing (DKK1+SOST) group, ERRα intervention empty adenovirus group, ERRα intervention silencing DKK1 group, ERRα intervention silencing SOST group, ERRα intervention silencing (DKK1+SOST) group. MG63 cells were transfected with packaged silencing DKK1 and SOST adenovirus vectors according to different groups. The activity of MG63 cells was detected by MTT assay, the activity of ALP was detected by alkaline phosphatase kit, and the concentration of calcium ion was analyzed by flow cytometry. Western blot was used to detect the expressions of low density lipoprotein associated protein 5 (LRP5), bone morphogenetic protein 2 (BMP2), osteopontin (OPN), osteoprotegerin(OPG).Results (1) Compared with blank control group, silencing DKK1, SOST, DKK1+SOST group and ERRα overexpression in the empty adenovirus group could increase cell activity, ALP activity, and decrease calcium ion concentration and increase the expressions of LRP5, BMP2, OPN, and OPG. Differences between groups were statistically significant(P0.05).Conclusion ERRα Overexpression can increase the activity of MG63 cells, ALP activity, LRP5, BMP2, OPN, and OPG proteins, and decrease the calcium ion concentration in silencing DKK1 and SOST adenovirus-transfected cells.

Mechanism of Sclerostin/Lrp4 in the regulation of vascular smooth muscle cell calcification / 中华肾脏病杂志

Objective To investigate the possible mechanism of sclerostin/Lrp4 in calcification of VSMC induced by high phosphorus and the protective effect of Ginkgo biloba extract.Methods Aortic vascular smooth muscle cells (VSMCs) of SD rats were extracted and identified.VSMCs were divided into normal control group,high phosphorus induced calcification group (10 mmol/L β-glycerophosphate+50 μg/ml ascorbic acid),and high phosphorus induced calcification+Ginkgo biloba extract intervention group (10 mmol/L β-glycerophosphate+50 μg/ml ascorbic acid+0.5 mg/ml GBE),cultured in different mediums for 14 days.Vonkossa staining and alizarin red staining were used to detect the calcification of VSMCs.The mRNA level of BGP was detected by real time PCR,and the protein expressions of sclerostin and Lrp4 were detected by Western blot.Results Compared with normal control group,vonkossa staining and alizarin red staining showed significant calcium deposition in calcification group.Compared with calcification group,calcium salt deposition was significantly reduced in GBE treatment group.Real time PCR results showed β-catenin and BGP mRNA expressions in VSMC calcification group were higher than those in normal control group (P＜ 0.05).mRNA expressions of β-catenin and BGP in GBE treatment group were lower than those in calcification group (all P ＜ 0.05).Compared with normal control group,the protein expression of sclerostin was increased,but the protein expression of Lrp4 was decreased in calcified group (all P ＜ 0.05).Compared with calcification group,the protein expression of sclerostin decreased and the protein expression of Lrp4 increased in GBE treatment group (all P ＜ 0.05).Conclusions High phosphorus can induce VSMC calcification by activating Wn/β-catenin signaling pathway.Sclerostin/Lrp4 is involved in hyperphosphine-induced VSMC calcification.GBE can reduce the high phosphorus induced VSMC calcification by regulating the Wnt/β-catenin signaling pathway.

Serum sclerostin and Dickkopf-related protein 1 levels of axial spondyloa rthritis can be raised by selective cyclo-oxygenase 2 inhibitor / 中华风湿病学杂志

Objective To investigate the serum levels of dickkopf-related protein 1 (DKK1) and sclerostin (SOST) in patients with axial spondyloarthritis treated with selective cyclo-oxygenase 2 inhibitor and its relation to clinical efficacy.Methods A randomized double-blind controlled trial with axial spondyloarthritis (ax-SpA) was carried out in our hospital.The data from patients in a single center was collected and analyzed.Serum DKK1 and SOST levels were measured by enzyme-linked immuno sorbent assay (ELISA)method before and after 12 weeks treatment,then correlation analysis were conducted for DKK1 and SOST levels with erythrocyte sedimentation rate (ESR),C reactive protein (CRP),Bath ankylosing spondylitis disease activity index (BASDAI),Bath ankylosing spondylitis functional index (BASFI) and SPARCC of the sacroiliac joint inflammation score.Chi-square tests were used for analyzing of categorical data.Fisher exact tests were performed when the expected frequencies were less than 5.Two independent samples t-test was used to compare the difference between groups.Single sample t-test was used to ompare the differences between data before and after treatment.Pearson or Spearman correlation was used for correlation analysis.Results After 12 weeks of treatment,a total of 116 patients completed the follow-up,including 57 cases of imrecoxib group and 59 cases of the celecoxib group.There were no statistically significant difference between the two groups (P＞0.05).The level of serum DKK1 was significantly increased after treatment [(393±137) pg/ml,vs (542±274)pg/ml,P＜0.05].The serum level of SOST increased significantly [(39±19) pg/ml vs (57±36) pg/ml,t=5.814,P＞0.05],too.The difference between the two groups was not statistically significant (P＞0.05).Spearman correlation analysis showed that serum DKK1 was positively correlated with serum SOST (r=0.226,P=0.015).A significantcorrelation was found between SOST level and ESR,CRP,finger to floor distance,left and fight lumbar side flexion and Schober's test (ESR:r=-0.379,P＜0.01;r=-0.309,P=0.001;r=-0.225,P=0.015;r=0.185,P=0.047;r=0.247,P=0.008;r=0.214,P=0.021).Conclusion Imrecoxib and celecoxib have similar efficacy on relieving the signs and symptoms of patients with ax-SpA.Short-term application of selective COX-2 inhibitors can increase DKK1 and SOST and possibly delay radiographic progression.

Relationship between plasma sclerostin and radiographic severity of knee osteoarthritis / 实用医学杂志

Objective To investigated the relationship between plasma sclerostin(SOST)and knee osteoar-thritis(KOA). Methods A total of 95 patients with KOA and 95 healthy people were involved.Plasma sclerostin, CTX-II, AGG1 and AGG2 levels were measured by ELISA. The 95 patients were divided based on Kellgren-Law-rence classification. The correlation between plasma SOST level and KL classification, CTX-II, AGG1 and AGG2 were analyzed.Results Plasma SOST level in KOA was significantly lower than that in control group(P<0.001). SOST level was negatively correlated with KL grade (r =-0.828,P < 0.001),also with CTX-II (r =-0.917,P <0.001),AGG1 (r =-0.658,P < 0.001) and AGG2 (r =-0.583,P < 0.001). Conclusions SOST level in KOA patients is related to the degree of cartilage degeneration. Thus, it helps to monitor the progress and evaluate the severity of the KOA.

Romosozumab for the treatment of osteoporosis

Romosozumab, a specific inhibitor of sclerostin, is a unique approach to therapy for postmenopausal osteoporosis and related disorders. The elucidation of sclerostin deficiency as the molecular defect of syndromes of high bone mass with normal quality, and the pivotal role of sclerostin as a mediator of osteoblastic activity and bone formation, provided the platform for the evaluation of inhibitors of sclerostin to activate bone formation. An extensive preclinical program and 2 large fracture endpoint trials with romosozumab, a sclerostin-binding antibody, have been completed. This review will highlight the results of those studies and describe the current status of romosozumab as a potential therapy for osteoporosis.

Research on the relationship of serum sclerostin level and bone density in maintenance hemodialysis patients / 中国综合临床

Objective To investigate whether serum sclerostin level is an indicator of the prognosis in patients with maintenance hemodialysis(MHD).Methods The clinical data of MHD patients treated in Yan′an University Affiliated Hospital in recent 3 years were collected to record their basic information and routine blood biochemical indexes.Serum Sclerostin levels were measured by ELISA calcaneus,while bone mineral density(BMD)was measured by quantitative ultrasound(QUS);correlation analysis was applied to screen the indicators affecting BMD.Logiest regression was used to look for protective factors and risk factors of low bone density;The correlation between serum sclerostin level and bone mineral density was analyzed,and ROC curve was used to explore whether serum sclerostin level could be used to predict low level bone mineral density.Results The median serum sclerostin concentration of 62 patients was 166.74(105.87,311.90)pmol/L.Spearman correlation analysis showed that serum sclerostin levels were positively correlated with BMI,serum calcium and 25(OH)VitD levels(r= 0.327,0.323,0.257,P= 0.010,0.049,0.044),while negatively correlated with lg[iPTH],spKt/v,triglyceride(TG),low density lipoprotein cholesterol(LDL-C)(r=-0.254,-0.279,-0.186,-0.314,P=0.046,0.012,0.027,0.031).Serum Sclerostin level was not related with serum phosphorus,alkaline phosphatase(AKP),high density lipoprotein cholesterol(HDL-C)and LDL(P>0.05) .Correlation analysis showed serum sclerostin levels were significantly and positively correlated with BMD(r=0.328,P=0.009).Logistic regression showed that serum sclerostin level was a risk factor for BMD(OR=1.17,95%CI(0.928~1.474);P=0.008).The ROC curve was established,and the area under the curve of serum sclerostin diagnosis was 87.9%.Conclusion Serum sclerostin levels are positively correlated with bone mineral density.And serum sclerostin levels may become a marker to predict the prognosis in MHD patients.

Association of sclerostin with fragility fractures in postmenopausal women / 第二军医大学学报

Objective To determine the relationship between circulating sclerostin levels and serum bone metabolism markers, bone mineral density (BMD) in postmenopausal women with or without fracture after falling, and to explore whether sclerostin can serve as a new biomarker to predict fragility fracture. Methods In this cross sectional and prospective study, 50 premenopausal women (group A), 50 postmenopausal women with femoral neck fracture after falling (group B) and 50 postmenopausal women without femoral neck fracture after falling (group C) were included. Observation items included serum sclerostin, bone metabolism markers and BMD. Results There were significant differences in bone metabolism markers (including C-terminal telopeptides of type collagen[CTX ], C-terminal telopeptides of type Ⅱ collagen[CTXⅡ], bone alkaline phosphatase[b-ALP], procollagen type 1 N-propeptide[P1NP], receptor activator of NF-κB[RANK] and receptor activator of NF-κB ligand[RANKL]) among three groups (P<0.05, P<0.01). The protein levels of sclerostin (P<0.05, P<0.01) and osteocalcin (P<0.01) in the group B and C were significantly higher than that in the group A, but there was no statistical difference between the group B and C. There were significant differences in BMD at the site of lumbar spine (from L1 to L4), total hip, trochanter or femoral neck among three groups (P<0.01), and the BMD in the group B was significantly lower than those in the group A and C (P<0.01). There were significant negative correlations between serum sclerostin level and mean femoral neck BMD (r=-0.228, P=0.004), mean trochanter BMD (r=-0.199, P=0.002) and mean total hip BMD (r=-0.273, P<0.001). Conclusion There is no statistical difference in serum sclerostin between postmenopausal women with and without femoral neck fracture after falling, suggesting that serum sclerostin levels may not be used to predict the potential risks of fraglity fracture in postmenopausal women.