LRP5 polymorphisms and response to alendronate treatment in Chinese postmenopausal women with osteoporosis

Abnormal Variations of the Key Genes in Osteoporotic Fractures

Objective. The classical osteoporotic signaling pathways include the four key genes (LRP5, Runx2, Osterix, and RANKL) influencing the regulation of osteogenesis and osteoclastogenesis. This study investigates the expression of these four genes associated with bone remodeling during fracture healing. Methods. Ovariectomized rats as an osteoporotic group were randomly divided into three groups-group A, group B, and group C. Nonosteoporotic rats as the control group were likewise divided into three groups A0, B0, and C0, using the same method. The rats were killed on the third day of fractures in groups A and A0, on the seventh day of fractures in groups B and B0, and on the fourteenth day of fractures in groups C and C0. The bone specimens were taken from the femoral fracture site, and the expression level of each gene in the bone specimens was detected using RT-qPCR, Western blotting, and immunohistochemistry. Results. LRP5, Runx2, and Osterix expressions were decreased in osteoporotic rat fractures and then increased over time. The expression of RANKL was elevated in osteoporotic rat bone specimens, which decreased after that. Conclusion. The expressions of the four genes varied with time after fracture, which could be associated with the various stages of bone repair. The four genes can inform practice in ideal interventions in the prevention and management of osteoporosis.

Genetic Polymorphisms of Nuclear Factor-κB Family Affect the Bone Mineral Density Response to Zoledronic Acid Therapy in Postmenopausal Chinese Women

The aim of this study was to explore the allelic association between genetic polymorphisms of the NF-κB pathway and the variance of clinical effects of zoledronic in postmenopausal Chinese women with osteoporosis. In the study, 110 Chinese postmenopausal women with osteoporosis were recruited. Every patient received zoledronic once a year. BMD was measured at baseline and after one year of treatment. The 13 tagger SNPs of five genes in the NF-κB pathway were genotyped. In the study, 101 subjects completed the one-year follow-up. The ITCTG and DTCTG haplotypes, which are constituted of rs28362491, rs3774937, rs230521, rs230510 and rs4648068 of the NF-κB1 gene, were associated with improvement in BMD at L1-4 and femoral neck (p < 0.001, p = 0.008, respectively). The CGC haplotype, which is constituted of rs7119750, rs2306365 and rs11820062 of the RELA gene, was associated with improvement in BMD at total hip (p < 0.001). After Bonferroni correction, haplotypes ITCTG and CGC still showed significant association with the % change of BMD at L1-4 and total hip. Therefore, NF-κB1 and RELA gene were significantly associated with bone response to the treatment of zoledronic in postmenopausal Chinese women with osteoporosis.

β-Ecdysterone Enhanced Bone Regeneration Through the BMP-2/SMAD/RUNX2/Osterix Signaling Pathway

Bone defects are a global public health problem. However, the available methods for inducing bone regeneration are limited. The application of traditional Chinese herbs for bone regeneration has gained popularity in recent years. β-ecdysterone is a plant sterol similar to estrogen, that promotes protein synthesis in cells; however, its function in bone regeneration remains unclear. In this study, we investigated the function of β-ecdysterone on osteoblast differentiation and bone regeneration in vitro and in vivo. MC3T3-E1 cells were used to test the function of β-ecdysterone on osteoblast differentiation and bone regeneration in vitro. The results of the Cell Counting Kit-8 assay suggested that the proliferation of MC3T3-E1 cells was promoted by β-ecdysterone. Furthermore, β-ecdysterone influenced the expression of osteogenesis-related genes, and the bone regeneration capacity of MC3T3-E1 cells was detected by polymerase chain reaction, the alkaline phosphatase (ALP) test, and the alizarin red test. β-ecdysterone could upregulate the expression of osteoblastic-related genes, and promoted ALP activity and the formation of calcium nodules. We also determined that β-ecdysterone increased the mRNA and protein levels of components of the BMP-2/Smad/Runx2/Osterix pathway. DNA sequencing further confirmed these target effects. β-ecdysterone promoted bone formation by enhancing gene expression of the BMP-2/Smad/Runx2/Osterix signaling pathway and by enrichment biological processes. For in vivo experiments, a femoral condyle defect model was constructed by drilling a bone defect measuring 3 mm in diameter and 4 mm in depth in the femoral condyle of 8-week-old Sprague Dawley male rats. This model was used to further assess the bone regenerative functions of β-ecdysterone. The results of micro-computed tomography showed that β-ecdysterone could accelerate bone regeneration, exhibiting higher bone volume, bone surface, and bone mineral density at each observation time point. Immunohistochemistry confirmed that the β-ecdysterone also increased the expression of collagen, osteocalcin, and bone morphogenetic protein-2 in the experiment group at 4 and 8 weeks. In conclusion, β-ecdysterone is a new bone regeneration regulator that can stimulate MC3T3-E1 cell proliferation and induce bone regeneration through the BMP-2/Smad/Runx2/Osterix pathway. This newly discovered function of β-ecdysterone has revealed a new direction of osteogenic differentiation and has provided novel therapeutic strategies for treating bone defects.

Polymorphisms of FDPS, LRP5, SOST and VKORC1 genes and their relation with osteoporosis in postmenopausal Romanian women

OBJECTIVES

This study aimed to assess the relationship between bone mineral density and genotypes of four polymorphisms in previously detected osteoporosis-candidate genes (FDPS rs2297480, LRP5 rs3736228, SOST rs1234612, VKORC1 rs9934438) in postmenopausal Romanian women with primary osteoporosis.

METHODS

An analytical, prospective, transversal, observational, case-control study on 364 postmenopausal Romanian women was carried out between June 2016 and August 2017 in Cluj Napoca, Romania. Clinical data and blood samples were collected from all study participants. Four polymorphisms were genotyped using TaqMan SNP Genotyping assays, run on a QuantStudio 3 real-time PCR machine.

RESULTS

Women with TT genotype in FDPS rs2297480 had significantly lower bone mineral density values in the lumbar spine and total hip, and the presence of the T allele was significantly associated with the osteoporosis. Women carrying the CC genotype in LRP5 rs3736228 tend to have lower bone mineral density values in the femoral neck and total hip. No significant association was found for the genotypes of SOST rs1234612 or VKORC1 rs9934438.

CONCLUSIONS

Our study showed a strong association between bone mineral density and polymorphisms in the FDPS gene, and a borderline association with LRP5 and SOST polymorphisms in postmenopausal Romanian women with osteoporosis. No association was found for VKORC1.

Genetic polymorphisms and their influence on therapeutic response to alendronate-a pilot study

Introduction: Osteoporosis has a strong genetic contribution, and several genes have been shown to influence bone mineral density. Variants in the human genome are considered important causes of differences in drug responses observed in clinical practice. In terms of bone mineral density, about 26–53% of patients do not respond to amino-bisphosphonate therapies, of which alendronate is the most widely used. Material and method: The current study is prospective, observational, analytical, longitudinal and cohort type. It included 25 postmenopausal women treated with alendronate for 1 year. Bone mineral density at lumbar spine and proximal femur was measured and bone turnover markers (C-terminal telopeptide of type I collagen and procollagen 1N-terminal propeptide) were evaluated at 0 and 12 months of treatment. Six single nucleotide polymorphisms in osteoporosis-candidate genes were genotyped (FDPS rs2297480, LRP5 rs3736228, SOST rs1234612, VKORC1 rs9934438, GGPS1 rs10925503 and RANKL rs2277439). Treatment response was evaluated by percentage changes in bone mineral density and bone turnover markers. Results: The heterozygous CT of FDPS rs2297480 showed lower increases in BMD values in the lumbar spine region and the homozygous CC of the GGPS1 rs10925503 showed lower increases in terms of BMD at the total hip region. No association was found for LRP5 rs3736228, SOST rs1234612, VKORC1 rs9934438 and RANKL rs2277439. Conclusions: Romanian postmenopausal women with osteoporosis carrying the CT genotype of FDPS rs2297480 or the CC genotype of GGPS1 rs10925503 could have an unsatisfactory response to alendronate treatment. Key words: osteoporosis; genetic polymorphism; alendronate; bone mineral density; bone turnover markers,

LRP5 gene polymorphisms and radiographic joint damage in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is characterized by increased bone resorption and impaired bone formation. Osteoblast function is regulated by the canonical LRP5/Wnt/β-catenin pathway. Bone mineral density and RA joint destruction are partially inherited. In line with this, we found significant associations between LRP5 SNPs (p.A1330V, p.N740N, p.V667M) and RA radiographic damage severity.

INTRODUCTION

Increased bone resorption and impaired bone formation characterize rheumatoid arthritis (RA). Canonical Wnt/β-catenin pathway, signalled by lipoprotein receptor-related protein-5 (LRP5), regulates osteoblast function. Since bone mineral density (BMD) and RA joint destruction are partially inherited, we studied their association with LRP5 single nucleotide polymorphisms (SNPs).

METHODS

Clinical data and peripheral blood for biomarkers assessment and LRP5 genotyping were collected from 208 RA patients. Hands and feet X-rays were scored [modified Sharp/van der Heijde Score (SHS), joint space narrowing (JSN), and erosion scores]. Lumbar spine, total left proximal femur, and left hand BMD were assessed by dual-energy X-ray absorptiometry (DXA).

RESULTS

TT genotypes for p.A1330V and p.N740N LRP5 SNPs associated with total SHS, erosion score, and hands erosion score; the same for p.A1330V with feet JSN score and p.N740N with hands total score. AG genotype for p.V667M associated with sclerostin and hands JSN score. Femoral BMD associated with TC genotype for p.N740N. Multiple test correction precluded a few of these associations. Among V667M-N740N-A1330V haplotypes: GTT associated with higher feet JSN score (OR = 3.80; p = 0.016) and ATT with higher JSN score (OR = 4.60; p = 0.032), hands total score (OR = 5.65; p = 0.022), and total SHS (OR = 6.74; p = 0.024).

CONCLUSION

Significant associations between LRP5 SNPs (p.A1330V, p.N740N, and p.V667M) and the severity of radiographic damage reinforce the evidence of bone destruction heritability in RA.

Reduced CpG island methylation of the TBC1D8 gene may predict risk for osteoporosis in Chinese postmenopausal women

Objective: In this study, we collected samples from postmenopausal women aged >60 y and evaluated bone mineral density (BMD) in addition to other biochemical variables to evaluate risk factors for osteoporosis. Furthermore, we investigated whether an association exists between the CpG island methylation levels in the promoter region of the TBC1D8 gene and osteoporosis incidence. Our goal was to identify contributing factors to the pathogenesis of osteoporosis and provide a theoretical basis for osteoporosis testing and therapy.

Materials and Methods: We used questionnaires to collect data from Chinese Han women in their communities. The following parameters were measured: uric acid, high density lipoprotein, low density lipoprotein, fasting blood glucose, serum creatinine, serum calcium, serum phosphorus, alkaline phosphatase, P1NP, β-CTX, PTH, 25(OH)D and bone mineral density from lumbar spine 1 to 4, femoral neck, and total hip. DNA was also extracted to assess the methylation level of the TBC1D8 gene.

Conclusions: Our findings suggest that a lower body mass index (BMI) infrequent exercise and certain sleep durations may be associated with osteoporosis. In addition, higher serum creatinine, β-CTX and PTH and lower 25(OH)D levels may be associated with osteoporosis. In Chinese Han postmenopausal women, decreased methylation of the TBCF1D8 gene promoter CpG islands is associated with osteoporosis. Finally, we also observed that TBC1D8 is negatively correlated with high density lipoprotein in postmenopausal women with osteoporosis.

Polymorphisms in key bone modulator cytokines genes influence bisphosphonates therapy in postmenopausal women

Osteoporosis is a multifactorial and debilitating disease resulting from decreased bone mineral density (BMD) and loss of tissue microarchitecture. Ineffective therapies may lead to bone fractures and subsequent death. Single nucleotide polymorphisms (SNPs) in key immune regulator genes have been associated with therapeutic response to bisphosphonates, which are the first therapeutic line of choice for osteoporosis. However, cytokine pathways and their relation with therapeutic adhesion remain to be fully elucidated. Aimed at better understanding these processes, we investigated the response to bisphosphonate therapy in postmenopausal women and four SNPs in key proinflammatory cytokines genes: IL23R +2284 (C>A) (rs10889677), IL17A +672 (G>A) (rs7747909), IL12B +1188 (T>G) (rs3212227) and INF-γ -1616 (G>A) (rs2069705). A total of 69 patients treated with bisphosphonate were followed for a period of 1 up to 4 years, genotyped and compared according to their changes in bone mineral density (BMD) and level of biochemical markers during their treatment. The INF-γ -1616 G/G associated with increased BMD values in femoral neck (GG/AA, p = 0.016) and decreased BMD values in total hip (GG/GA, p = 0.019; GG/AA, p = 0.011). In relation to biochemical markers, INF-γ -1616 SNP associated with increased alkaline phosphatase (GG/AA; p < 0.0001) and parathyroid hormone levels (AA/GA; p = 0.017). Vitamin D values changes were related to IL17A +672 (GG/GA, p = 0.034) and to IL12B +1188 (TT/TG, p = 0.046) SNPs. Besides, significant differences in changes of calcium levels correlated with IL23R +2284 (CC/CA, p = 0.016) genotypes. Altogether, we suggest that these polymorphisms may play an important role for therapeutic decisions in osteoporosis treatment.

Association Between Geranylgeranyl Pyrophosphate Synthase Gene Polymorphisms and Bone Phenotypes and Response to Alendronate Treatment in Chinese Osteoporotic Women

Objective To investigate the relationship between geranylgeranyl pyrophosphate synthase (GGPPS) gene polymorphisms and bone response to alendronate in Chinese osteoporotic women.Methods A total of 639 postmenopausal women with osteoporosis or osteopenia were included and randomly received treatment of low dose (70 mg per two weeks) or standard dose (70 mg weekly) of alendronate for one year. The six tag single nucleotide polymorphisms of GGPPS gene were identified. Bone mineral density (BMD), serum cross-linked C-telopeptide of type I collagen (β-CTX), and total alkaline phosphatase (ALP) were measured before and after treatment. GGPPS gene polymorphisms and the changes of BMD and bone turnover markers after treatment were analyzed.Results rs10925503 polymorphism of GGPPS gene was correlated to serum β-CTX levels at baseline, and patients with TT genotype had significantly higher serum β-CTX level than those with TC or CC genotype (all P<0.05). No correlation was found between polymorphisms of GGPPS gene and serum total ALP levels, as well as BMD at baseline. After 12 months of treatment, lumbar spine and hip BMD increased and serum bone turnover markers decreased significantly (P<0.01), and without obvious differences between the low dose and standard dose groups (all P>0.05). However, GGPPS gene polymorphisms were uncorrelated to percentage changes of BMD, serum total ALP, and β-CTX levels (all P>0.05).Conclusion GGPPS gene polymorphisms are correlated to osteoclasts activity, but all tag single nucleotide polymorphisms of GGPPS gene have no influence on the skeletal response to alendronate treatment.

The analysis of DKK1 polymorphisms in relation to skeletal phenotypes and bone response to alendronate treatment in Chinese postmenopausal women

Aim: To investigate the correlation between DKK1 polymorphisms with bone phenotypes and response to alendronate treatment. Materials & methods: Five tag single nucleotide polymorphisms of DKK1 were analyzed in 639 Chinese postmenopausal women with osteoporosis or osteopenia. Bone mineral density (BMD), β-CTX and ALP were measured before and after alendronate treatment. Results: Genotypes at rs1896367, rs1528877 and rs2241529 correlated to baseline BMD (p < 0.05). rs1528877 and rs2241529 polymorphisms correlated to baseline β-CTX levels (p < 0.05). rs2241529 polymorphisms of DKK1 had a small influence on the skeletal response to alendronate treatment (p < 0.05). Conclusion: DKK1 polymorphisms may correlate to baseline BMD and serum β-CTX levels, but present a weak effect on the response to alendronate.

SOST polymorphisms and response to alendronate treatment in postmenopausal Chinese women with osteoporosis

AIM

To investigate the association between SOST gene polymorphisms and response to alendronate treatment.

MATERIALS & METHODS

639 Chinese postmenopausal women with osteoporosis or osteopenia received alendronate treatment. Polymorphisms of SOST were analyzed. Bone mineral density (BMD), serum ALP and β-CTX levels were measured. The correlation of SOST polymorphisms with changes of BMD and bone biomarkers after treatment was analyzed.

RESULTS

rs1234612 and rs851054 polymorphisms were correlated to baseline lumbar spine BMD (p < 0.05). After 12 months of treatment rs1234612 and rs865429 polymorphisms were correlated to BMD changes at the lumbar spine (p < 0.05) or femoral neck (p < 0.05), respectively.

CONCLUSION

The polymorphisms of SOST are genetic factors affecting bone health and response to alendronate in Chinese postmenopausal women.