Association between Secreted Phosphoprotein-1 (SPP1) Polymorphisms and Low Bone Mineral Density in Women

Background

A recent meta-analysis found that secreted phosphoprotein-1 (SPP1) can predict the risk of both osteoporosis and fracture. No study has explored the association of SPP1 haplotype-tagging single nucleotide polymorphisms (htSNPs) and haplotypes with bone mineral density (BMD).

Methods

This is a cross-sectional study. A total of 1,313 healthy Taiwanese women aged 40 to 55 years were recruited from MJ Health Management Institute from 2009 to 2010. BMD was dichotomized into high and low BMD groups. Three common (allele frequency ≥5%) htSNPs were selected to examine the association between sequence variants of SPP1 and BMD.

Results

Homozygosity for the T allele of rs4754 were protective from low BMD [TT vs. CC: adjusted OR (AOR)  = 0.58, 95% confidence interval (CI)  = 0.83–0.89]. A protective effect was also found for women carrying 2 copies of Hap3 TCT (AOR  = 0.57, 95% CI  = 0.34–0.95). Menopausal status marginally interacted with SPP1 rs6839524 on BMD (p = 0.049). Postmenopausal women carrying variant rs6839524 (GG+GC vs. CC: AOR  = 2.35, 95% CI  = 1.06–5.20) or Hap1 TGC (AOR  = 2.36, 95% CI  = 1.06–5.24) were associated with 2.4-fold risk of low BMD. For women with low BMI (<18.5 kg/m²), variant rs6839524 (AOR  = 7.64) and Hap1 (AOR  = 6.42) were associated with increased risk of low BMD. These findings did not reach statistical significance after correction for multiple tests.

Conclusions

SPP1 htSNP protected against low BMD in middle-aged women. SPP1 genetic markers may be important for the prediction of osteoporosis at an early age.     

REV-ERB ALPHA Polymorphism Is Associated with Obesity in the Spanish Obese Male Population

REV-ERB ALPHA has been shown to link metabolism with circadian rhythms. We aimed to identify new polymorphisms in the promoter of REV-ERB ALPHA and tested whether these polymorphisms could be associated with obesity in the Spanish population. Of the 1197 subjects included in our study, 779 were obese (BMI 34.38±3.1 kg/m²) and 418 lean (BMI 23.27±1.5 kg/m²). In the obese group, 469 of the 779 had type 2 diabetes. Genomic DNA from all the subjects was obtained from peripheral blood cells and the genotyping in the REV-ERB ALPHA promoter was analyzed by High Resolution Melting. We found six polymorphisms in the REV-ERB ALPHA promoter and identified rs939347 as a SNP with the highest frequency in the total population. We did not find any association between rs939347 and type 2 diabetes (p = 0.101), but rs939347 was associated with obesity (p = 0.036) with the genotype AA exhibiting higher frequency in the obese (5.2% in total obese vs 2.4% in lean). This association was found only in men (p = 0.031; 6.5% AA-carriers in obese men vs 1.9% AA-carriers in lean men), with no association found in the female population (p = 0.505; 4.4% AA-carriers in obese women vs 2.7% AA-carriers in lean women). Our results suggest that the REV-ERB ALPHA rs939347 polymorphism could modulate body fat mass in men. The present work supports the role of REV-ERB ALPHA in the development of obesity as well as a potential target for the treatment of obesity.     

Association between VDR Apal Polymorphism and Hip Bone Mineral Density Can Be Modified by Body Mass Index:A Study on Postmenopausal Chinese Women

Osteoporosis is a major public health problem for old people.Genetic factors are considered tobe major contributors to the pathogenesis of postmenopausal osteoporosis.The vitamin D receptor(VDR)gene is a prominent candidate gene for the regulation of postmenopausal bone mass;however,despite exten-sive studies,controversy remains regarding its association with postmenopausal body mineral density(BMD)variation.In this study,a total of 260 healthy postmenopausal Chinese women were genotyped at the VDRApaI locus using polymerase chain reaction(PCR)-restriction fragment length polymorphism (RFLP).Rawhip BMD was significantly associated with VDR ApaI polymorphism with and without adjusting for age(P=0.015 and 0.040,respectively).This genetic effect can explain 3.32% of hip BMD variation.However,the significant association vanished after correcting for both age and body mass index(BMI)(P=0.169).Inaddition,we observed a significant association between VDR ApaI polymorphism with unadjusted BMI(P=0.042)or BMI adjusted for age(P=0.049).The raw hip BMD was also found to be significantly corre-lated with BMI(r=0.517,P=0.0001),with BMI explaining 26.35% of the variation of hip BMD.All of thesefacts prompt us to conclude that the significant association between the VDR ApaI genotype and hip BMDmay be modified by BMI in postmenopausal Chinese women.Our findings may partially explain the earlierinconsistent association results concerning the VDR gene and BMD,and highlight the importance of incorpo-rating covariates such as BMI into osteoporosis association studies.     

1,25-Dihydroxyvitamin D and the Vitamin D Receptor Gene Polymorphism Apa1 Influence Bone Mineral Density in Primary Hyperparathyroidism

Objective

Parathyroid hormone (PTH) and vitamin D are the most important hormones regulating calcium metabolism. In primary hyperparathyroidism (PHPT) excessive amounts of PTH are produced. Bone turnover is enhanced, leading to reduced bone mineral density and elevated levels of serum calcium. The aim of this study was to investigate relations between serum levels of 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)₂D) and bone mineral density, as well as known genetic polymorphisms in the vitamin D receptor and enzymes metabolising vitamin D in patients with PHPT.

Design/Subjects

We conducted a cross-sectional study of 52 patients with PHPT.

Results

Mean level of 25(OH)D was 58.2 nmol/L and median 1,25(OH)₂D level was 157 pmol/L. Among our patients with PHPT 36.5% had 25(OH)D levels below 50 nmol/L. Serum 1,25(OH)₂D was inversely correlated to bone mineral density in distal radius (p = 0.002), but not to bone mineral density at lumbar spine or femoral neck. The vitamin D receptor polymorphism Apa1 (rs7975232) was associated with bone mineral density in the lumbar spine.

Conclusions

The results suggest that PHPT patients with high blood concentrations of 1,25(OH)₂D may have the most deleterious skeletal effects. Randomized, prospective studies are necessary to elucidate whether vitamin D supplementation additionally increases serum 1,25(OH)₂D and possibly enhances the adverse effects on the skeleton in patients with PHPT.     

Drosophila Pheromone-Sensing Neurons Expressing the ppk25 Ion Channel Subunit Stimulate Male Courtship and Female Receptivity

As in many species, gustatory pheromones regulate the mating behavior of Drosophila. Recently, several ppk genes, encoding ion channel subunits of the DEG/ENaC family, have been implicated in this process, leading to the identification of gustatory neurons that detect specific pheromones. In a subset of taste hairs on the legs of Drosophila, there are two ppk23-expressing, pheromone-sensing neurons with complementary response profiles; one neuron detects female pheromones that stimulate male courtship, the other detects male pheromones that inhibit male-male courtship. In contrast to ppk23, ppk25, is only expressed in a single gustatory neuron per taste hair, and males with impaired ppk25 function court females at reduced rates but do not display abnormal courtship of other males. These findings raised the possibility that ppk25 expression defines a subset of pheromone-sensing neurons. Here we show that ppk25 is expressed and functions in neurons that detect female-specific pheromones and mediates their stimulatory effect on male courtship. Furthermore, the role of ppk25 and ppk25-expressing neurons is not restricted to responses to female-specific pheromones. ppk25 is also required in the same subset of neurons for stimulation of male courtship by young males, males of the Tai2 strain, and by synthetic 7-pentacosene (7-P), a hydrocarbon normally found at low levels in both males and females. Finally, we unexpectedly find that, in females, ppk25 and ppk25-expressing cells regulate receptivity to mating. In the absence of the third antennal segment, which has both olfactory and auditory functions, mutations in ppk25 or silencing of ppk25-expressing neurons block female receptivity to males. Together these results indicate that ppk25 identifies a functionally specialized subset of pheromone-sensing neurons. While ppk25 neurons are required for the responses to multiple pheromones, in both males and females these neurons are specifically involved in stimulating courtship and mating.     

SIRT1 Polymorphism,Long-Term Survival and Glucose Tolerance in the General Population

Mutations that increase activity of Sir2 (silent information regulator 2) are associated with extended lifespan of yeast, fruit flies and worms. SIRT1, the human homolog of Sir2, that controls numerous physiological processes including the glucose metabolism, is considered a candidate gene for predicting variation in human lifespan. Whereas the role of Sir2 has been extensively investigated in model organisms, less is known about the relation between SIRT1 and lifespan in humans. In the current study we included 1,390 subjects from a general population-based cohort with 18 years of follow-up to investigate associations between variation in single nucleotide polymorphisms (SNPs) in the SIRT1 gene and human survival. Additionally in 535 male subjects with available data we investigated associations between SIRT1 and glucose tolerance. Carriers of the minor allele of rs12778366 had a significantly reduced mortality risk compared to the wild types: Hazard Ratio 0.69 (95% CI 0.50 to 0.96; p = 0.025). The directions of the effect were the same in females and males, never and ever smokers and the effect was significantly protective in overweight/obese subjects. Carriers of the minor allele of SNP rs12778366 had better glucose tolerance indicated by 0.34 mmol/l lower glucose levels compared to wild type subjects (p = 0.03). This study shows that SIRT1 affects human long-term survival and therefore may be an important factor in modulating lifespan not only in lower organisms, but also in humans.     

Oesophagostomum dentatum Extract Modulates T Cell-Dependent Immune Responses to Bystander Antigens and Prevents the Development of Allergy in Mice

One third of the human population is currently infected by one or more species of parasitic helminths. Certain helminths establish long-term chronic infections resulting in a modulation of the host’s immune system with attenuated responsiveness to “bystander” antigens such as allergens or vaccines. In this study we investigated whether parasite-derived products suppress the development of allergic inflammation in a mouse model. We show that extract derived from adult male Oesophagostomum dentatum (eMOD) induced Th2 and regulatory responses in BALB/c mice. Stimulation of bone marrow-derived dendritic cells induced production of regulatory cytokines IL-10 and TGF-beta. In a mouse model of birch pollen allergy, co-administration of eMOD with sensitizing allergen Bet v 1 markedly reduced the production of allergen-specific antibodies in serum as well as IgE-dependent basophil degranulation. Furthermore, eMOD prevented the development of airway inflammation, as demonstrated by attenuation of bronchoalveolar lavages eosinophil influx, peribronchial inflammatory infiltrate, and mucus secretion in lungs and IL-4 and IL-5 levels in lung cell cultures. Reduced secretion of Th2-related cytokines by birch pollen-re-stimulated splenocytes and mesenteric lymph node cells was observed in eMOD-treated/sensitized and challenged mice in comparison to sensitized and challenged controls. The suppressive effects of eMOD were heat-stable. Immunization with model antigens in the presence of eMOD reduced production of antibodies to thymus-dependent but not to thymus-independent antigen, suggesting that suppression of the immune responses by eMOD was mediated by interference with antigen presenting cell or T helper cell function but did not directly suppress B cell function. In conclusion, we have shown that eMOD possesses immunomodulatory properties and that heat-stable factors in eMOD are responsible for the dramatic suppression of allergic responses in a mouse model of type I allergy. The identification and characterization of parasite-derived immune-modulating molecules might have potential for designing novel prophylactic/therapeutic strategies for immune-mediated diseases.     

MAPKAP1 rs10118570 Polymorphism Is Associated with Anti-Infection and Anti-Hepatic Fibrogenesis in Schistosomiasis Japonica

Chronic infection with Schistosoma japonicum is an important cause of hepatic fibrosis (HF). Human 9q33.3 is one of the most important loci for stress-related diseases. We examined the potential associations of 43 single-nucleotide polymorphisms (SNPs) with S. japonicum infection and HF in epidemic region in China. We identified a SNP (rs10118570 GG in mitogen-activated protein kinase associated protein 1, MAPKAP1) contributes to anti-infection (adjusted OR = 0.35) and anti-fibrogenesis (adjusted RR = 0.44) in the discovery study. Replicative and combined studies showed consistent protective quality for this genotype (replicative: adjusted OR = 0.37 for anti-infection, and adjusted RR = 0.40 for anti-fibrogenesis; Combined: adjusted OR = 0.45 for anti-infection, and adjusted RR = 0.42 for anti-fibrogenesis). Univariate and multivariate analysis in the discovery, replicative and combined studies, suggested that durations (years), splenomegaly, serum ALB and rs10118570 were independent predictors influencing the fibrogenesis. The analysis of gene-gene interaction showed rs10118570 functions independently. We conclude that MAPKAP1 may represent a novel anti-infection and anti-fibrogenesis genomic locus in chronic schistosomiasis japonica. And rs10118570 may be a potential biomarker and target for the treatment of this life-threatening ancient disease.     

VNN1 Gene Expression Levels and the G-137T Polymorphism Are Associated with HDL-C Levels in Mexican Prepubertal Children

Background

VNN1 gene expression levels and the G-137T polymorphism have been associated with high density lipoprotein cholesterol (HDL-C) levels in Mexican American adults. We aim to evaluate the contribution of VNN1 gene expression and the G-137T variant to HDL-C levels and other metabolic traits in Mexican prepubertal children.

Methodology/Principal Findings

VNN1 mRNA expression levels were quantified in peripheral blood leukocytes from 224 unrelated Mexican-Mestizo children aged 6–8 years (107 boys and 117 girls) and were genotyped for the G-137T variant (rs4897612). To account for population stratification, a panel of 10 ancestry informative markers was analyzed. After adjustment for admixture, the TT genotype was significantly associated with lower VNN1 mRNA expression levels (P = 2.9 × 10⁻⁵), decreased HDL-C levels (β = −6.19, P = 0.028) and with higher body mass index (BMI) z-score (β = 0.48, P = 0.024) in the total sample. In addition, VNN1 expression showed a positive correlation with HDL-C levels (r = 0.220; P = 0.017) and a negative correlation with BMI z-score (r = −0.225; P = 0.015) only in girls.

Conclusion/Significance

Our data suggest that VNN1 gene expression and the G-137T variant are associated with HDL-C levels in Mexican children, particularly in prepubertal girls.     

Nup154, a New Drosophila Gene Essential for Male and Female Gametogenesis Is Related to the Nup155 Vertebrate Nucleoporin Gene

The Nup154 gene of Drosophila encodes a protein showing similarity with known nucleoporins: rat Nup155 and yeast Nup170 and Nup157. Hypomorphic mutant alleles of Nup154 affected female and male fertility, allowing investigation of the gene function in various steps of oogenesis and spermatogenesis. Nup154 was required in testes for cyst formation, control of spermatocyte proliferation and meiotic progression. In ovaries, Nup154 was essential for egg chamber development and oocyte growth. In both the male and female germ line, as well as in several other cell types, the Nup154 protein was detected at the nuclear membrane, but was also present inside the nucleus. Intranuclear localization has not previously been described for rat Nup155 or yeast Nup170 and Nup157. In mutant egg chambers the Nup154 protein accumulated in the cytoplasm, while it was only barely detected at the nuclear envelopes. FG repeats containing nucleoporins detected with mAb414 antibody were also mislocalized to a certain extent in Nup154 mutant alleles. This suggests that Nup154 could be required for localizing other nucleoporins within the nuclear pore complex, as previously demonstrated for the yeast Nup170. On the other hand, no evident defects in lamin localization were observed, indicating that Nup155 mutations did not affect the overall integrity of the nuclear envelope. However, ultrastructural analyses revealed that in mutant cells the morphology of the nuclear envelope was altered near the nuclear pore complexes. Finally, the multiplicity of phenotypes observed in Nup154 mutant alleles suggests that this gene plays a crucial role in cell physiology.     

Plasmodium falciparum UvrD Helicase Translocates in 3′ to 5′ Direction,Colocalizes with MLH and Modulates Its Activity through Physical Interaction

Malaria is a global disease and a major health problem. The control of malaria is a daunting task due to the increasing drug resistance. Therefore, there is an urgent need to identify and characterize novel parasite specific drug targets. In the present study we report the biochemical characterization of parasite specific UvrD helicase from Plasmodium falciparum. The N-terminal fragment (PfUDN) containing UvrD helicase domain, which consists of helicase motifs Q, Ia–Id, II, III and most of motif IV, and the C-terminal fragment (PfUDC1) containing UvrD helicase C terminal domain, consisting of remaining part of motif IV and motifs IVa–IVc and 161 amino acids of intervening sequence between motif IV and V, possess ssDNA-dependent ATPase and DNA helicase activities in vitro. Using immunodepletion assays we show that the ATPase and helicase activities are attributable to PfUDN and PfUDC1 proteins. The helicase activity can utilize the hydrolysis of all the nucleotide and deoxynucleotide triphosphates and the direction of unwinding is 3′ to 5′. The endogenous P. falciparum UvrD contains the characteristic DNA helicase activity. PfUDN interacts with PfMLH (P. falciparum MutL homologue) and modulates the endonuclease activity of PfMLH and PfMLH positively regulates the unwinding activity of PfUDN. We show that PfUvrD is expressed in the nucleus distinctly in the schizont stages of the intraerythrocytic development of the parasite and it colocalizes with PfMLH. These studies will make an important contribution in understanding the nucleic acid transaction in the malaria parasite.     

PAI-1 -675 4G/5G Polymorphism in Association with Diabetes and Diabetic Complications Susceptibility: a Meta-Analysis Study

A meta-analysis was performed to assess the association between the PAI-1 -675 4G/5G polymorphism and susceptibility to diabetes mellitus (DM), diabetic nephropathy (DN), diabetic retinopathy (DR) and diabetic coronary artery disease (CAD). A literature-based search was conducted to identify all relevant studies. The fixed or random effect pooled measure was calculated mainly at the allele level to determine heterogeneity bias among studies. Further stratified analyses and sensitivity analyses were also performed. Publication bias was examined by the modified Begg’s and Egger’s test. Twenty published articles with twenty-seven outcomes were included in the meta-analysis: 6 studies with a total of 1,333 cases and 3,011 controls were analyzed for the PAI-1 -675 4G/5G polymorphism with diabetes risk, 7 studies with 1,060 cases and 1,139 controls for DN risk, 10 studies with 1,327 cases and 1,557 controls for DR and 4 studies with 610 cases and 1,042 controls for diabetic CAD risk respectively. Using allelic comparison (4G vs. 5G), the PAI-1 -675 4G/5G polymorphism was observed to have no significant association with diabetes (REM OR 1.07, 95% CI 0.96, 1.20), DN (REM OR 1.10, 95% CI 0.98, 1.25), DR (REM OR 1.09, 95% CI 0.97, 1.22) or diabetic CAD risk (REM OR 1.07, 95% CI 0.81, 1.42), and similar results were obtained in the dominant, recessive and co-dominant models. Our meta-analyses suggest that the PAI-1 -675 4G/5G polymorphism might not be a risk factor for DM, DN, DR or diabetic CAD risk in the populations investigated. This conclusion warrants confirmation by further studies.     

腹部脂肪分布与2型糖尿病合并肥胖患者胰岛素抵抗和骨密度的关系研究

目的:探讨腹部脂肪分布与2型糖尿病合并肥胖患者胰岛素抵抗和骨密度的相关性。方法:选择2017年2月至2019年7月青岛大学附属医院内分泌与代谢病科收治的159例肥胖合并2型糖尿病患者(观察组)和同期100例单纯性肥胖且口服葡萄糖糖耐量试验(OGTT)正常者(对照组)。采用多层螺旋CT(MSCT)测量腹腔内脂肪面积(VFA)、腹内脂肪体积(IAFV)、全腹脂肪体积(TAV),并计算IAFV/TAV;采用全自动生化分析仪检测受试者血脂、空腹血糖(FPG)、空腹胰岛素(FINS)水平,并计算胰岛素抵抗指数(HOMA-IR);采用骨密度仪测量腰椎骨密度、股骨骨密度、髋骨骨密度。分析VFA、IAFV、TAV、IAFV/TAV与胰岛素抵抗和骨密度之间相关性。结果:观察组VFA、IAFV、IAFV/TAV、FPG、HOMA-IR、FINS、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)高于对照组(P0.05),高密度脂蛋白胆固醇(HDL-C)、腰椎骨密度、股骨骨密度、髋骨骨密度低于对照组(P0.05),TAV与对照组比较差异无统计学意义(P0.05)。Pearson相关分析结果示VFA、IAFV、IAFV/TAV与FPG、HOMA-IR、FINS、TC、TG、LDL-C呈正相关(P0.05),与腰椎、股骨、髋骨骨密度、HDL-C呈负相关(P0.05),偏相关分析结果显示,VFA、IAFV、IAFV/TAV与HOMA-IR呈正相关(P0.05),与腰椎、股骨、髋骨骨密度呈负相关(P0.05)。结论:腹内脂肪异常堆积与2型糖尿病合并肥胖患者胰岛素抵抗和骨密度具有显著相关性,临床可通过检测腹内脂肪分布情况预估2型糖尿病合并肥胖患者发生胰岛素抵抗和骨质疏松的风险。     

1H-NMR and MS Based Metabolomics Study of the Intervention Effect of Curcumin on Hyperlipidemia Mice Induced by High-Fat Diet

Curcumin, a principle bioactive component of Curcuma longa L, is well known for its anti-hyperlipidemia effect. However, no holistic metabolic information of curcumin on hyperlipidemia models has been revealed, which may provide us an insight into the underlying mechanism. In the present work, NMR and MS based metabolomics was conducted to investigate the intervention effect of curcumin on hyperlipidemia mice induced by high-fat diet (HFD) feeding for 12 weeks. The HFD induced animals were orally administered with curcumin (40, 80 mg/kg) or lovastatin (30 mg/kg, positive control) once a day during the inducing period. Serum biochemistry assay of TC, TG, LDL-c, and HDL-c was conducted and proved that treatment of curcumin or lovastatin can significantly improve the lipid profiles. Subsequently, metabolomics analysis was carried out for urine samples. Orthogonal Partial Least Squares-Discriminant analysis (OPLS-DA) was employed to investigate the anti-hyperlipidemia effect of curcumin and to detect related potential biomarkers. Totally, 35 biomarkers were identified, including 31 by NMR and nine by MS (five by both). It turned out that curcumin treatment can partially recover the metabolism disorders induced by HFD, with the following metabolic pathways involved: TCA cycle, glycolysis and gluconeogenesis, synthesis of ketone bodies and cholesterol, ketogenesis of branched chain amino acid, choline metabolism, and fatty acid metabolism. Besides, NMR and MS based metabolomics proved to be powerful tools in investigating pharmacodynamics effect of natural products and underlying mechanisms.     

A Functional Calvin Cycle Is Not Indispensable for the Light Activation of C4 Phosphoenolpyruvate Carboxylase Kinase and Its Target Enzyme in the Maize Mutant bundle sheath defective2-mutable1

We used a pale-green maize (Zea mays L.) mutant that fails to accumulate ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) to test the working hypothesis that the regulatory phosphorylation of C₄ phosphoenolpyruvate carboxylase (PEPC) by its Ca²⁺-insensitive protein-serine/threonine kinase (PEPC kinase) in the C₄ mesophyll cytosol depends on cross-talk with a functional Calvin cycle in the bundle sheath. Wild-type (W22) and bundle sheath defective2-mutable1 (bsd2-m1) seeds were grown in a controlled environment chamber at 100 to 130 μmol m⁻² s⁻¹ photosynthetic photon flux density, and leaf tissue was harvested 11 d after sowing, following exposure to various light intensities. Immunoblot analysis showed no major difference in the amount of polypeptide present for several mesophyll- and bundle-sheath-specific photosynthetic enzymes apart from Rubisco, which was either completely absent or very much reduced in the mutant. Similarly, leaf net CO₂-exchange analysis and in vitro radiometric Rubisco assays showed that no appreciable carbon fixation was occurring in the mutant. In contrast, the sensitivity of PEPC to malate inhibition in bsd2-m1 leaves decreased significantly with an increase in light intensity, and there was a concomitant increase in PEPC kinase activity, similar to that seen in wild-type leaf tissue. Thus, although bsd2-m1 mutant plants lack an operative Calvin cycle, light activation of PEPC kinase and its target enzyme are not grossly perturbed.