The TMEM127 human tumor suppressor is a component of the mTORC1 lysosomal nutrient-sensing complex.

The TMEM127 tumor suppressor gene encodes a transmembrane protein of unknown function mutated in pheochromocytomas and, rarely, in renal cancers. Tumors with inactivating TMEM127 mutations have increased mTORC1 signaling by undefined mechanisms. Here we report that TMEM127 interacts with the lysosome-anchored complex comprised of Rag GTPases, the LAMTOR pentamer (or 'ragulator') and vATPase, which controls amino acid-mediated mTORC1 activation. We found that under nutrient-rich conditions TMEM127 expression reduces mTORC1 recruitment to Rags. In addition, TMEM127 interacts with LAMTOR in an amino acid-dependent manner and decreases the LAMTOR1-vATPase association, while TMEM127-vATPase binding requires intact lysosomal acidification but is amino acid independent. Conversely, both murine and human cells lacking TMEM127 accumulate LAMTOR proteins in the lysosome. Consistent with these findings, pheochromocytomas with TMEM127 mutations have increased levels of LAMTOR proteins. These results suggest that TMEM127 interactions with ragulator and vATPase at the lysosome contribute to restrain mTORC1 signaling in response to amino acids, thus explaining the increased mTORC1 activation seen in TMEM127-deficient tumors.

Anion- and Solvent-Induced Single-Crystal-to-Single-Crystal Transformation within an Iron(II) Triazole System: a Promising Luminescent Probe for CrO42- and Cyano-Containing Molecules.

Anion- and solvent-induced single-crystal-to-single-crystal transformation within an iron(II) triazole system has been generated from {[Fe(TPPT)2Cl2]·CHCl3} n (1a) to [Fe(TPPT)(C2O4)0.5Cl(H2O)] n (1b). Luminescence studies indicated that the resultant 1b can be considered as a promising luminescent probe for CrO42- and cyano molecules.

Spectrum and prevalence of FP/TMEM127 gene mutations in pheochromocytomas and paragangliomas.

CONTEXT: Pheochromocytomas and paragangliomas are genetically heterogeneous neural crest-derived neoplasms. We recently identified germline mutations of the novel transmembrane-encoding gene FP/TMEM127 in familial and sporadic pheochromocytomas consistent with a tumor suppressor effect. OBJECTIVES: To examine the prevalence and spectrum of FP/TMEM127 mutations in pheochromocytomas and paragangliomas and to test the effect of mutations in vitro. DESIGN, SETTING, AND PARTICIPANTS: We sequenced the FP/TMEM127 gene in 990 individuals with pheochromocytomas and/or paragangliomas, including 898 previously unreported cases without mutations in other susceptibility genes from 8 independent worldwide referral centers between January 2009 and June 2010. A multiplex polymerase chain reaction-based method was developed to screen for large gene deletions in 545 of these samples. Confocal microscopy of 5 transfected mutant proteins was used to determine their subcellular localization. MAIN OUTCOME MEASURES: The frequency and type of FP/TMEM127 mutation or deletion was assessed and correlated with clinical variables; the subcellular localization of 5 overexpressed mutants was compared with wild-type FP/TMEM127 protein. RESULTS: We identified 19 potentially pathogenic FP/TMEM127 germline mutations in 20 independent families, but no large deletions were detected. All mutation carriers had adrenal tumors, including 7 bilateral (P = 2.7 × 10(-4)) and/or with familial disease (5 of 20 samples; P = .005). The median age at disease onset in the FP/TMEM127 mutation group was similar to that of patients without a mutation (41.5 vs 45 years, respectively; P = .54). The most common presentation was that of a single benign adrenal tumor in patients older than 40 years. Malignancy was seen in 1 mutation carrier (5%). Expression of 5 novel FP/TMEM127 mutations in cell lines revealed diffuse localization of the mutant proteins in contrast with the discrete multiorganelle distribution of wild-type TMEM127. CONCLUSIONS: Germline mutations of FP/TMEM127 were associated with pheochromocytoma but not paraganglioma and occurred in an age group frequently excluded from genetic screening algorithms. Disease-associated mutations disrupt intracellular distribution of the FP/TMEM127 protein.

Clinical Parameters, Fuel Oxidation, and Glucose Kinetics in Patients With Type 2 Diabetes Treated With Dapagliflozin Plus Saxagliptin.

OBJECTIVE: To examine the mechanisms responsible for improved glycemia with combined sodium-glucose cotransporter 2 inhibitor (SGLT2i) plus dipeptidyl peptidase 4 inhibitor therapy in type 2 diabetes. RESEARCH DESIGN AND METHODS: Fifty-six patients (HbA1c 8.9 ± 0.2% [74 ± 2 mmol/mol]) were randomized to dapagliflozin (DAPA) 10 mg, DAPA/saxagliptin (SAXA) 10/5 mg, or placebo (PCB) for 16 weeks. Basal endogenous glucose production (EGP) (3-3H-glucose), urinary glucose excretion, glucose/lipid oxidation, HbA1c, and substrate/hormone levels were determined before treatment (Pre-Tx) and after treatment (Post-Tx). RESULTS: At week 16, HbA1c decrease was greater (P < 0.05) in DAPA/SAXA (-2.0 ± 0.3%) vs. DAPA (-1.4 ± 0.2%) and greater than PCB (0.2 ± 0.2%). Day 1 of drug administration, EGP (∼2.40 mg/kg/min) decreased by -0.44 ± 0.09 mg/kg/min in PCB (P < 0.05) but only by -0.21 ± 0.02 mg/kg/min in DAPA and DAPA/SAXA (P < 0.05 vs. PCB). At week 16, EGP increased to 2.67 ± 0.09 mg/kg/min (DAPA) and 2.61 ± 0.08 mg/kg/min (DAPA/SAXA), despite reductions in fasting plasma glucose by 47 and 77 mg/dL, respectively, and no changes in PCB. Baseline plasma free fatty acids rose by 40 µmol/L with DAPA but declined by -110 with PCB and -90 µmol/L with DAPA/SAXA (P < 0.05, Pre-Tx vs. Post-Tx). In DAPA, carbohydrate oxidation rates decreased from 1.1 ± 0.1 to 0.7 ± 0.1 mg/kg/min, whereas lipid oxidation rates increased from 0.6 ± 0.1 to 0.8 ± 0.1 mg/kg/min (P < 0.01). In DAPA/SAXA, the shift in carbohydrate (1.1 ± 0.1 to 0.9 ± 0.1 mg/kg/min) and lipid (0.6 ± 0.1 to 0.7 ± 0.1 mg/kg/min) oxidation was attenuated (P < 0.05). CONCLUSIONS: The addition of SAXA to DAPA resulted in superior glycemic control compared with DAPA monotherapy partly because of increased glucose utilization and oxidation. Although the decrease in insulin/glucagon ratio was prevented by SAXA, EGP paradoxical elevation persisted, indicating that other factors mediate EGP changes in response to SGLT2i-induced glucosuria.

[Osteoprotegerin gene polymorphism and therapeutic response to alendronate in postmenopausal women with osteoporosis].

OBJECTIVE: To investigate whether the polymorphism of osteoprotegerin (OPG) gene is associated with the change of BMD (bone mineral density) after alendronate therapy in postmenopausal women with osteoporosis and determine the correlation between genotypes and therapeutic effect. METHODS: Eighty postmenopausal osteoporotic patients were recruited with an average age of (64.2 +/- 7.7) years old. Every patient took oral alendronate (Fosamax) 70 mg weekly and Caltrate 600 mg daily for 12 months. At pre- and post-treatment, BMD was measured at lumbar spine 2 - 4 and hip sites. PCR-RFLP was performed for three polymorphisms at the promoter site of OPG gene (A163G, T245G and T950C). RESULTS: One-year therapy was accomplished in 67 patients. Patients with G allele (genotype AG and GG) of site A163G, the baseline BMD of vertebral L2-4, inter-troche and total hip were lower than genotype AA [(0.732 +/- 0.113) g/cm(2) vs (0.819 +/- 0.157) g/cm(2), (0.775 +/- 0.101) g/cm(2) vs (0.843 +/- 0.124) g/cm(2) and (0.667 +/- 0.105) g/cm(2) vs (0.725 +/- 0.091) g/cm(2)]. Patients with G allele (genotype TG and GG) of site T245G, baseline BMD of vertebral L2-4, inter-troche and total hip were lower than genotype TT [(0.723 +/- 0.111) g/cm(2) vs (0.819 +/- 0.155) g/cm(2), (0.776 +/- 0.102) g/cm(2) vs (0.840 +/- 0.124) g/cm(2) and (0.670 +/- 0.109) g/cm(2) vs (0.721 +/- 0.091) g/cm(2)]. After one-year therapy, at site A163G, the percentage of BMD change at inter-troche was higher in genotype AA than in genotypes AG and GG [2.50 (3.47)% vs 0.88% (3.47%)%, P = 0.014]. While at site T245G, the percentage of BMD change at inter-troche and total hip were higher in genotype TT than in genotype TG and GG 2.50% (3.47%) vs 0.61% (3.31%), P = 0.011; 2.72% (2.68%) vs 0.89 (3.01%), P = 0.046]. CONCLUSION: The G allele of sites A163G and T245G may be the risk allele of postmenopausal osteoporosis. Furthermore, patients with genotypes AA (A163G) and (T245G) show a better therapeutic effect to alendronate.

The tumor suppressor TMEM127 regulates insulin sensitivity in a tissue-specific manner.

Understanding the molecular components of insulin signaling is relevant to effectively manage insulin resistance. We investigated the phenotype of the TMEM127 tumor suppressor gene deficiency in vivo. Whole-body Tmem127 knockout mice have decreased adiposity and maintain insulin sensitivity, low hepatic fat deposition and peripheral glucose clearance after a high-fat diet. Liver-specific and adipose-specific Tmem127 deletion partially overlap global Tmem127 loss: liver Tmem127 promotes hepatic gluconeogenesis and inhibits peripheral glucose uptake, while adipose Tmem127 downregulates adipogenesis and hepatic glucose production. mTORC2 is activated in TMEM127-deficient hepatocytes suggesting that it interacts with TMEM127 to control insulin sensitivity. Murine hepatic Tmem127 expression is increased in insulin-resistant states and is reversed by diet or the insulin sensitizer pioglitazone. Importantly, human liver TMEM127 expression correlates with steatohepatitis and insulin resistance. Our results suggest that besides tumor suppression activities, TMEM127 is a nutrient-sensing component of glucose/lipid homeostasis and may be a target in insulin resistance.

A germline mutation of the KIF1B beta gene on 1p36 in a family with neural and nonneural tumors.

Recently, the KIF1B beta gene on 1p36, a region commonly deleted in neural crest cancers, was found to be a proapoptotic factor for sympathetic precursors. KIF1B beta mutations were detected in pheochromocytomas and neuroblastomas, two sympathetic lineage tumors, suggesting a role for this gene in cancer. Here, we studied five individuals from a three-generation cancer-prone family with a KIF1B beta germline variant and seven of their tumors, both of neural crest and nonneural origin. Genetic studies including sequencing, copy number analysis and fluorescence in situ-hybridization (FISH) showed retention of both KIF1B beta alleles in all neural crest-derived tumors in this family, consistent with haploinsufficiency or methylation of the wild-type allele. In contrast, the lung adenocarcinoma from one mutation carrier had somatic loss of the wild-type allele in agreement with a classical two-hit inactivation. Global transcription analysis of KIF1B beta mutant pheochromocytomas revealed that these tumors are transcriptionally related to pheochromocytomas with RET and NF1 mutations but independent from SDH- and VHL-associated tumors. Furthermore, KIF1B beta-mutant tumors are uniquely enriched for pathways related to glutamate metabolism and the oxidative stress response. Our data start to delineate the signals that are disrupted by KIF1B beta dysfunction in pheochromocytomas and suggest that loss of this gene may also be permissive to the development of nonneural crest malignancies. This may imply the existence of a tissue-specific gene dosage requirement for its tumorigenesis.

Age-related changes of serum tartrate-resistant acid phosphatase 5b and the relationship with bone mineral density in Chinese women.

AIM: Osteoclastic activity is mainly assessed by measurement of urinary markers (eg C-terminal cross-linked telopeptides of type I collagen, N-terminal crosslinked telopeptides of type I collagen, etc), the levels of which could often be affected by renal clearance. Recently, serum tartrate-resistant acid phosphatase 5b (TRACP5b) has been used as an alternative serum marker to evaluate osteoclastic activity. We investigated the age-related changes of TRACP5b level and its association with bone mineral density (BMD) in Chinese women. METHODS: Seven-hundred and twenty-two Chinese mainland women aged 20-79 years were recruited in the study. Serum TRACP5b level was measured using immunoassay to evaluate the state of bone resorption. Bone mineral density (BMD) (g/cm2) at lumbar spine 1-4 and proximal femur were measured by duelenergy X-ray absorptiometry. RESULTS: The serum TRACP5b level reached a bottom value in premenopausal women aged 30-39, gradually increased in women aged 40-49, rapidly rose in women aged 50-59, and culminated with a maximum value in women aged 60-69 before a slow drop in women aged 70- 79. The average level of TRACP5b was significantly higher in postmenopausal women [(3.29+/-1.07) U/L] than in premenopausal women ([1.70+/-0.59] U/L). The levels of TRACP5b were inversely correlated with BMD at all measured sites (P<0.001). Furthermore, the level of TRACP5b was obviously higher in women with osteoporosis and osteopenia than those with normal bone mass (P<0.001). CONCLUSION: We have established the reference values of serum TRACP5b in Chinese mainland women, and found that postmenopausal women had higher TRACP5b concentration than younger women. The results showed that serum TRACP5b was a sensitive and useful parameter for the evaluation of age-related changes of bone absorption.

[Development of a simple predicting tool for low bone mass of postmenopausal women: a study in Shanghai].

OBJECTIVE: To develop a simple screening tool for low bone mass of postmenopausal women. METHODS: 405 postmenopausal women in Shanghai who visited the department of osteoporosis consecutively, aged 62.8 +/- 8.0 (47 approximately 90), underwent questionnaire survey on the risk factors of osteoporosis and fracture. Dual energy X-ray absorptiometry (DXA) was conducted on the left or right femoral neck to measure the bone mineral density (BMD) to identify osteoporosis (T-score

Bone mineral density of the spine and femur in healthy Chinese men.

AIM: To establish bone mineral density (BMD) reference database in healthy Chinese men of Han ethnicity, and to estimate the prevalence of osteoporosis in the population. METHODS: The BMD in the lumbar spine 1-4 (L1-4) and proximal femur was measured using dual energy X-ray absorptiometry in a total of 1 385 healthy Chinese men of Han ethnicity aged 20-89 years old in Shanghai. RESULTS: The highly significant negative correlation between age and BMD at any sites of proximal femur was found in the studied population, wheras no correlation between age and BMD at lumbar spine was observed. The peak BMD of the lumbar spine and any sites of hip in Chinese men was defined as the mean BMD for the subjects aged 20-89 years. According to World Health Organization (WHO) criteria, the BMD cut-off values for osteoporosis of the L1-4, total hip, femoral neck, trochanter and intertrochanter in Chinese men are 0.719, 0.638, 0.575, 0.437 and 0.725 g/cm(2), respectively. Using the current Chinese reference data, the prevalence of osteoporosis at the L1-4, total hip, femoral neck, trochanter and intertrochanter is 5.4%, 3.8%, 6.3%, 1.8% and 2.8% in 1 084 men aged 50 years or older, respectively. However, using a database for US non-Hispanic white men (NHANES III), the prevalence of osteoporosis or osteopenia at any sites of the hip was significantly higher than that while using the current Chinese reference data. CONCLUSION: The BMD reference database was established in healthy Chinese men of Han ethnicity, and will facilitate more accurate diagnosis of osteoporosis in Chinese men.

[Relationship between the polymorphism of start codon and CDX2 site in vitamin D receptor gene and the effect of calcium supplementation on bone mineral density of postmenopausal women].

OBJECTIVE: To investigate the association of polymorphisms of start codon (Fok I site) and CDX2 binding site in vitamin D receptor gene (VDR) concerned with the effect of calcium supplementation on bone mineral density (BMD) and bone turnover markers of postmenopausal women. METHODS: Two hundreds unrelated postmenopausal women of Han ethnicity in Shanghai were randomly divided into 2 groups of 100 women: high calcium group (1000 mg element calcium and 400 units of vitamin D were given daily for 12 months) and low calcium group (300 mg element calcium and 300 units of vitamin D were given daily for 12 months). BMD and bone turnover markers were measured at baseline and 12 months after calcium supplementation. VDR gene Fok I and CDX2 polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele-specific multiplex PCR, respectively. RESULTS: One hundred and seventy-one women completed 12-month study period. The frequency of VDR Fok I genotypes was 48.0 % for Ff, 31.0 % for FF, and 21.0 % for ff, and the frequency of CDX2 genotypes was 56.7 % for AG, 25.7% for GG, and 17.6% for AA. The frequencies distribution of Fok I and CDX2 alleles in the entire population or in two subgroups all followed the Hardy-Weinberg equilibrium. No significant difference of baseline BMD and bone turnover markers in Fok I genotypes or CDX2 genotypes was observed in the entire population or in two subgroups. Moreover, regardless of calcium supplementation given for 12 months, no significant association was found between Fok I or CDX2 polymorphisms and the endpoint values or percentage changes of any BMD and bone turnover markers in either high calcium group or low calcium group. CONCLUSION: There is no significant relationship between VDR gene Fok I or CDX2 polymorphisms and the effect of high or low doses calcium supplementation on BMD and bone turnover markers in Shanghai postmenopausal women of Han ethnicity.

Association of bone metabolism related genes polymorphisms with the effect of raloxifene hydrochloride on bone mineral density and bone turnover markers in postmenopausal women with osteoporosis.

OBJECTIVE: To investigate the association of bone metabolism related genes polymorphisms with the effect of raloxifene hydrochloride(RLX) on bone mineral density (BMD) and bone turnover markers in postmenopausal women with osteoporosis. METHODS: A total of 68 unrelated postmenopausal women with osteoporosis of Han ethnicity aged 47-74 years were randomly divided into 2 groups of 34 women: RLX group (60 mg were given daily for 12 months) and placebo group. BMD and bone turnover markers were measured at baseline, 6 and 12 months after treatment. The polymorphisms of Xba I and Pvu II sites in estrogen receptor 1 gene(ESR1), Ras I site in ESR2 gene, and start codon (Fok I) and CDX2 binding sites in vitamin D receptor gene (VDR) were analyzed. RESULTS: A total of 58 patients completed 12 months of study period. By the end of study, the increased percentage of BMD in lumbar spine 2-4 (L2-4), total hip, and trochanter were found significantly different between RLX group and placebo group(P<0.05), and the decreased percentage of C-telopeptide and osteocalcin were significantly different between the two groups (P<0.01). The BMD of total hip and trochanter of women with FF genotypes of VDR Fok I site were decreased by 1.98%+/-4.86% and 2.26%+/-4.73% respectively in the RLX group, but those of women with Ff/ff genotypes were increased by 2.52%+/-2.75% and 2.74 %+/-2.97%, respectively(P<0.05). Moreover, the total hip BMD of women with PP/Pp genotypes of ESR1 Pvu II site was increased by 2.12%+/-2.78%, and of women with pp genotype it was decreased by 1.34%+/-3.73%(P<0.05). However, no significant association was observed of the polymorphisms of five sites with the changes of BMD and bone turnover markers in the placebo group. CONCLUSION: The effect of RLX on BMD in postmenopausal women with osteoporosis is regulated by the polymorphisms of Fok I of VDR gene and Pvu II of ESR1 gene. The study is valuable to select this drug according to genotype of patients in clinical.

[Do the premenopausal daughters of women with postmenopausal osteoporosis have lower peak bone mass?].

OBJECTIVE: To determine whether premenopausal daughters of women with postmenopausal osteoporosis have lower peak bone mass than the daughters of normal women the same age, and to analyze the related risk factors affecting bone mass variation. METHODS: 126 pairs of mother with postmenopausal osteoporosis and her premenopausal daughter, and 136 pairs of normal postmenopausal mother and her premenopausal daughter selected for 410 core families including one healthy premenopausal daughter aged 20 - 40, all of Han ethnicity living in Shanghai recruited by advertisement and lectures. A questionnaire survey was conducted to investigate their dietary custom, Dual-energy X-ray absorptiometry at lumber spine 1 - 4 (L(1 - 4)) and proximal femur was conducted to measure the values of bone mineral density (BMD). RESULTS: The BMD values in L(1 - 4), femoral neck, and greater trochanter of the daughters of mothers with osteoporosis were 0.68 g/cm(2) +/- 0.07 g/cm(2), 0.59 g/cm(2) +/- 0.08 g/cm(2), and 0.47 g/cm(2) +/- 0.07 g/cm(2) respectively, all significantly lower than those of the daughters of normal mothers (0.86 g/cm(2) +/- 0.14 g/cm(2), 0.70 g/cm(2) +/- 0.11 g/cm(2), and 0.57 g/cm(2) +/- 0.10 g/cm(2) respectively, all P < 0.001). The average body weight of the daughters of mothers with osteoporosis was lighter then that of the daughters of normal mothers by 4.8% (P < 0.05). Multivariate regression analysis showed that age, body height, age of menarche, and milk intake were not influencing factors of BMD value, however, body weight was most significantly associated with BMD of the premenopausal daughters, contributing to the BMD variation at L(1 - 4), femoral neck, and greater trochanter by 9.4%, 16.5%, and 16.6% respectively. When body weight was excluded in the model, lower BMD of mother became the most important factors affecting the BMD variation, contributing to the BMD variation at L(1 - 4), femoral neck, and greater trochanter by 5.1%, 5.3%, and 4.2% respectively. CONCLUSION: The daughters of mothers with osteoporosis have reduced peak bone mass. It is likely due to the lower body weight of the daughter and the lower bone mass of the mother.

Recurrent Mutations of Chromatin-Remodeling Genes and Kinase Receptors in Pheochromocytomas and Paragangliomas.

PURPOSE: Pheochromocytomas and paragangliomas (PPGL) are genetically heterogeneous tumors of neural crest origin, but the molecular basis of most PPGLs is unknown. EXPERIMENTAL DESIGN: We performed exome or transcriptome sequencing of 43 samples from 41 patients. A validation set of 136 PPGLs was used for amplicon-specific resequencing. In addition, a subset of these tumors was subjected to microarray-based transcription, protein expression, and histone methylation analysis by Western blotting or immunohistochemistry. In vitro analysis of mutants was performed in cell lines. RESULTS: We detected mutations in chromatin-remodeling genes, including histone-methyltransferases, histone-demethylases, and histones in 11 samples from 8 patients (20%). In particular, we characterized a new cancer syndrome involving PPGLs and giant cell tumors of bone (GCT) caused by a postzygotic G34W mutation of the histone 3.3 gene, H3F3A Furthermore, mutations in kinase genes were detected in samples from 15 patients (37%). Among those, a novel germline kinase domain mutation of MERTK detected in a patient with PPGL and medullary thyroid carcinoma was found to activate signaling downstream of this receptor. Recurrent germline and somatic mutations were also detected in MET, including a familial case and sporadic PPGLs. Importantly, in each of these three genes, mutations were also detected in the validation group. In addition, a somatic oncogenic hotspot FGFR1 mutation was found in a sporadic tumor. CONCLUSIONS: This study implicates chromatin-remodeling and kinase variants as frequent genetic events in PPGLs, many of which have no other known germline driver mutation. MERTK, MET, and H3F3A emerge as novel PPGL susceptibility genes. Clin Cancer Res; 22(9); 2301-10. ©2015 AACR.

No major effect of the insulin-like growth factor I gene on bone mineral density in premenopausal Chinese women.

Osteoporosis is a major public health problem, mainly characterized by low bone mineral density (BMD). BMD is a complex trait that is determined by multiple genes. Insulin-like growth factor I (IGF-I) is an important growth factor of bone and thus IGF-I gene has been considered as an attractive candidate gene for osteoporosis. A few studies on the relationship between variants of the IGF-I gene and BMD variation, via traditional association and/or linkage methods, have yielded conflicting results. In this study, we simultaneously tested association and/or linkage of a cytosine-adenine (CA) repeat polymorphism at 1 kb upstream of the transcription initiation site of the IGF-I gene with BMD variation in a large cohort of premenopausal Chinese women. A total of 1263 subjects from 402 Chinese nuclear families were examined. Each family consists of both parents and at least one daughter aged between 20 and 45 years. BMDs (g/cm(2)) at the lumbar spine and hip were measured using dual-energy X-ray absorptiometry (DXA). Applying the QTDT (quantitative transmission disequilibrium tests) progam, we did not find significant evidence of association or linkage between the CA repeat polymorphism of the IGF-I gene and BMD variation at any skeletal site. Our data do not support the IGF-I gene having major effect on BMD variation in premenopausal Chinese women.

[Association of Xba I, Pvu II, and Bst U I polymorphisms of estrogen receptor-alpha gene with bone mass in men].

OBJECTIVE: To investigate the association of polymorphism in estrogen receptor-alpha (ER-alpha ) gene with bone mineral density(BMD) in men. METHODS: The ER-alpha Xba I, Pvu II and Bst UI genotypes were determined by PCR-restriction fragment length polymorphism (RFLP) in 388 unrelated healthy men who were 46-80 years old and were of Han nationalities in Shanghai city. Bone mineral densities (BMD, g/cm(2)) at lumbar spines 1-4 (L(1-4)) and at any sites of proximal femur, including femoral neck (Neck), trochanter (Troch) and Ward's triangle (Ward's) were measured by duel-energy X-ray absorptiometry. RESULTS: The frequencies distribution of Xba I and Pvu II alleles and genotypes in this cohort all followed the Hardy-Weinberg equilibrium. No Bst UI polymorphic site in ER-alpha gene was found in total samples. All subjects were of BB genotype. No significant association was found between Xba I genotype and BMD at any skeleton sites. The significant association was found between Pvu II genotype and BMD at L(1-4) and Ward's triangle site (P< 0.05). Compared against men with PP and pp genotype, men with Pp genotype had significantly higher mean BMD at L(1-4) and Ward's triangle site (P< 0.05). CONCLUSION: This study suggests that Bst UI polymorphism in ER-alpha gene may be absent or rare in Chinese Han population. Pvu II polymorphism possibly influences the loss of trabecular bone mass in old men.

D2HGDH regulates alpha-ketoglutarate levels and dioxygenase function by modulating IDH2.

Isocitrate dehydrogenases (IDH) convert isocitrate to alpha-ketoglutarate (α-KG). In cancer, mutant IDH1/2 reduces α-KG to D2-hydroxyglutarate (D2-HG) disrupting α-KG-dependent dioxygenases. However, the physiological relevance of controlling the interconversion of D2-HG into α-KG, mediated by D2-hydroxyglutarate dehydrogenase (D2HGDH), remains obscure. Here we show that wild-type D2HGDH elevates α-KG levels, influencing histone and DNA methylation, and HIF1α hydroxylation. Conversely, the D2HGDH mutants that we find in diffuse large B-cell lymphoma are enzymatically inert. D2-HG is a low-abundance metabolite, but we show that it can meaningfully elevate α-KG levels by positively modulating mitochondrial IDH activity and inducing IDH2 expression. Accordingly, genetic depletion of IDH2 abrogates D2HGDH effects, whereas ectopic IDH2 rescues D2HGDH-deficient cells. Our data link D2HGDH to cancer and describe an additional role for the enzyme: the regulation of IDH2 activity and α-KG-mediated epigenetic remodelling. These data further expose the intricacies of mitochondrial metabolism and inform on the pathogenesis of D2HGDH-deficient diseases.

Estrogen receptor alpha gene polymorphisms and peak bone density in Chinese nuclear families.

PBD is an important determinant of osteoporotic fractures. Few studies were performed to search for genes underlying PBD variation in Chinese populations. We tested linkage and/or association of the estrogen receptor alpha gene polymorphism with PBD in 401 Chinese nuclear families. This study suggests the ER-alpha gene may have some minor effects on PBM variation in the Chinese population. Low peak bone density (PBD) in adulthood is an important determinant of osteoporotic fractures in the elderly. PBD variation is mainly regulated by genetic factors. Extensive molecular genetics studies have been performed to search for genes underlying PBD variation, largely in whites. Few studies were performed in Chinese populations. In this study, we simultaneously test linkage and/or association of the estrogen receptor alpha (ER-alpha) gene polymorphism with PBD in 401 Chinese nuclear families (both parents plus their female children) of 1260 subjects, with the 458 children generally between 20 and 40 years of age. All the subjects were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) at polymorphic PvuII and XbaI sites inside the ER-alpha gene. Bone mineral density was measured at the lumbar spine (L1-L4) and hip (femoral neck, trochanter, and intertrochanteric region). Raw bone mineral density values were adjusted by age, height, and weight as covariates. We detected marginally significant results for within-family association (transmission disequilibrium; p = 0.054) between the spine bone mineral density variation and the ER-alpha XbaI genotypes. For the hip bone mineral density variation, significant (p < 0.05) linkage results were generally found for the two intragenic markers. Analyses of the haplotypes defined by the two markers confer further evidence for linkage of the ER-alpha with the hip PBD variation. In conclusion, this study suggests that the ER-alpha gene may have minor effects on PBD variation in our Chinese population.

Effects of raloxifene hydrochloride on bone mineral density, bone metabolism and serum lipids in Chinese postmenopausal women with osteoporosis: a multi-center, randomized, placebo-controlled clinical trial.

BACKGROUND: Raloxifene has been approved for prevention and treatment of postmenopausal osteoporosis in Caucasian women. It also has some positive effects on serum lipids in Caucasians. The objective of this study was to determine the effect of raloxifene hydrochloride on lumbar spine and total hip bone mineral density (BMD), bone metabolism, and serum lipids in Chinese postmenopausal women with osteoporosis. METHODS: This was a multi-center, randomized, double-blind, placebo-controlled clinical trial in which 204 postmenopausal Chinese women with osteoporosis were assigned to receive raloxifene (60 mg) or placebo treatment daily for 12 months. BMD, serum bone metabolism markers, and serum lipids were measured before and after drug administration. BMD was measured by Dual-Energy X-Ray Absorptiometry (DEXA) and bone metabolism markers were analyzed by one-step enzyme-linked immunosorbent assay. Serum lipids were measured by enzymatic analysis. RESULTS: At the end of the 12-month study, lumbar spine BMD increased in both groups with a mean increase of (3.3 +/- 4.8)% in the raloxifene group and (1.0 +/- 4.9)% in the placebo group (P < 0.001). There was a mean increase in total hip BMD of (1.4 +/- 4.8)% in the raloxifene group and a mean decrease of (0.9 +/- 5.0)% in the placebo group (P < 0.001). No subject in the raloxifene group had a new vertebral fracture and 5 placebo subjects had new fractures (P > 0.05). In the raloxifene group, the median decreases in the biochemical markers of bone metabolism serum osteocalcin and C-telopeptide were 41.7% and 61.5%, respectively. These changes were statistically significant compared with those in the placebo group (10.6% and 35.6%, P < 0.001, respectively). Both total cholesterol and low-density lipoprotein cholesterol decreased significantly in the raloxifene group compared with those in the placebo group (P < 0.001, respectively) and there was no significant effect of raloxifene on high-density lipoprotein cholesterol and triglycerides compared with placebo. CONCLUSIONS: Raloxifene 60 mg/d for 12 months significantly increases lumbar spine and total hip BMD, significantly decreases bone turnover, and has favourable effects on serum lipids in Chinese postmenopausal women with osteoporosis.

[Effect of raloxifene hydrochloride on bone mineral density, bone metabolism and serum lipids in Chinese postmenopausal women with osteoporosis].

OBJECTIVE: To determine the effect of raloxifene hydrochloride (RLX) on the lumbar spine and total hip bone mineral density (BMD), bone metabolism and serum lipids in Chinese postmenopausal women with osteoporosis. METHODS: 204 Chinese postmenopausal women with osteoporosis from 3 hospitals in Beijing and Shanghai were randomly divided into 2 groups of 102 women: RLX group (RLX of the dosage of 60 mg/day was given for 12 months) and placebo group. In addition, 500 mg of elemental calcium and 200 units of vitamin D were given daily to all women. BMD, serum bone markers and lipids were measured before and after drug administration. The BMD of lumber spine and hip was measured by dual-energy X-ray absorptiometry (DEXA). Serum bone gamma-carboxyglutamic acid-containing protein (BGP) and C-teloppeptide were analyzed by one-step ELISA. Serum lipids were measured by enzymatic method. RESULTS: By the end of the 12-month study period, the lumbar spine BMD was increased by 3.3% +/- 4.8% in the RLX group and 1.0% +/- 4.9% in the placebo group (P < 0.001); the hip BMD was increased by 1.4% +/- 4.8%in the RLX group and decreased by 0.9% +/- 5.0% in the placebo group (P < 0.01). New vertebral fracture occurred in none of the subjects in the RLX group and in 5 subjects of the placebo group (P = 0.059). The serum BGP and CTX decreased by 41.7% and 61.5% respectively in the RLX group, both significantly more than those in the placebo group (10.6% and 35.6% respectively, both P < 0.001). Both the total cholesterol and low-density lipoprotein cholesterol were significantly lower in the RLX group than in the placebo group (both P < 0.001), however, there were no significant differences in high-density lipoprotein cholesterol and triglycerides between these two groups. One subject in the RLX group and 5 subjects in the placebo group discontinued the study due to adverse events. There were no differences in the number of subjects with hot flushes (3 in the RLX group and 1 in the placebo group) and the number of subjects with leg cramps (9 in the RLX group and 4 in the placebo group). No venous thromboembolic event was reported. CONCLUSION: RLX of the dosage of 60 mg/day for 12 months significantly increases the lumbar spine and total hip bone BMD, significantly decreases bone turnover and has favorable effects on serum lipids in Chinese postmenopausal women with osteoporosis.