👤 Wanqing Wen

Extensive studies have demonstrated that biochanin A (BCA) has a significant hypolipidemic effect. However, its mechanism of action is not clear. In this context, the effect of BCA on a high-fat diet (HFD)-induced hyperlipidemia in mice was determined. The results showed that treatment with a medium dose of biochanin A (BM) significantly decreased low-density lipoprotein cholesterol (LDL-C) 85% (from 1.196 ± 0.183 to 0.181 ± 0.0778 mM) and total cholesterol (TC) 39% (from 5.983 ± 0.128 to 3.649 ± 0.374 mM) levels, increased lipoprotein lipase (LPL) 96% (from 1.421 ± 0.0982 to 2.784 ± 0.177 U/mg protein) and hepatic triglyceride lipase (HTGL) 78% (from 1.614 ± 0.0848 to 2.870 ± 0.0977 U/mg protein) activities, significantly improved fecal lipid levels, and lowered the epididymal fat index in hyperlipidemic mice compared with the HFD control mice (p < 0.05). In vitro, the high antioxidant capacity of BCA was determined by the FRAP assay, ABTS Show less

To identify novel candidate genes and gene sets for diabetes. We performed an integrative analysis of genome-wide association studies (GWAS) and expression quantitative trait loci (eQTLs) data for diabetes. Summary data was driven from a large-scale GWAS of diabetes, totally involving 58,070 individuals. eQTLs dataset included 923,021 cis-eQTL for 14,329 genes and 4,732 trans-eQTL for 2,612 genes. Integrative analysis of GWAS and eQTLs data was conducted by summary data-based Mendelian randomization (SMR). To identify the gene sets associated with diabetes, the SMR single gene analysis results were further subjected to gene set enrichment analysis (GSEA). A total of 13,311 annotated gene sets were analyzed in this study. SMR analysis identified 6 genes significantly associated with fasting glucose, such as C11ORF10 ( Our study provides novel clues for clarifying the genetic mechanism of diabetes. This study also illustrated the good performance of SMR approach and extended it to gene set association analysis for complex diseases. Show less

Yes-associated protein (YAP) is a transcriptional coactivator in the Hippo pathway that regulates cell proliferation, differentiation, and apoptosis. The MEK5/ERK5 MAPK cascade is essential for the early step of myogenesis. In this study, we generated C2C12 stable cell lines that expressed YAP (C2C12-YAP cells) and found that ERK5 and MEK5 were activated in C2C12-YAP cells compared with control C2C12 (C2C12-vector) cells. C2C12-YAP stable cells also differentiated into myotubes better than C2C12-vector cells, and expressed elevated levels of myogenin, a transcription factor that regulates myogenesis, as well as elevated levels of myosin heavy chain, a skeletal muscle marker. Western blot analysis revealed that Src and c-Abl (Abelson murine leukemia viral oncogene homolog 1) activation were enhanced in C2C12-YAP cells. Conversely, treatment of inhibitors of c-Abl, Src, or MEK5 inhibited activation of MEK5 and ERK5 and myogenesis of C2C12 myoblasts. Specific interactions between YAP and proteins in the ERK5 pathway, such as MEK kinase 3 (MEKK3) and ERK5, were illustrated by coimmunoprecipitation experiments. MEKK3 contains the PPGY motif (aa 178-181), which may interact with YAP. Site-directed mutagenesis experiments revealed that expression of MEKK3 Y181F mutant inhibited MEK5/ERK5 activation and myogenic differentiation. These results suggest that YAP promotes muscle differentiation by activating the Abl/Src/MEKK3/MEK5/ERK5 kinase cascade.-Chen, T.-H., Chen, C.-Y., Wen, H.-C., Chang, C.-C., Wang, H.-D., Chuu, C.-P., Chang, C.-H. YAP promotes myogenic differentiation Show less

Lower adipose-ChREBP and de novo lipogenesis (DNL) are associated with insulin resistance in humans. Here, we generated adipose-specific ChREBP knockout (AdChREBP KO) mice with negligible sucrose-induced DNL in adipose tissue (AT). Chow-fed AdChREBP KO mice are insulin resistant with impaired insulin action in the liver, muscle, and AT and increased AT inflammation. HFD-fed AdChREBP KO mice are also more insulin resistant than controls. Surprisingly, adipocytes lacking ChREBP display a cell-autonomous reduction in insulin-stimulated glucose transport that is mediated by impaired Glut4 translocation and exocytosis, not lower Glut4 levels. AdChREBP KO mice have lower levels of palmitic acid esters of hydroxy stearic acids (PAHSAs) in serum, and AT. 9-PAHSA supplementation completely rescues their insulin resistance and AT inflammation. 9-PAHSA also normalizes impaired glucose transport and Glut4 exocytosis in ChREBP KO adipocytes. Thus, loss of adipose-ChREBP is sufficient to cause insulin resistance, potentially by regulating AT glucose transport and flux through specific lipogenic pathways. Show less

Atherosclerosis attracts increasing global attention because of its morbidity and mortality. G004, as a synthetic sulfonylurea compound, has been confirmed to have anti-hyperglycaemia, anti-platelet and anti-thrombus effects. The aim of the present study was to investigate whether G004 suppress the onset and development of atherosclerosis and illuminate its probable mechanism of action. ApoE Show less

Autophagy is essential for maintaining cellular homeostasis and survival under various stress conditions. Autophagy-related gene 9 (Atg9) encodes a multipass transmembrane protein thought to act as a membrane carrier for forming autophagosomes. However, the molecular regulation and physiological importance of Atg9 in animal development remain largely unclear. Here, we generated Show less

Gene-by-environment (GxE) interactions determine common disease risk factors and biomedically relevant complex traits. However, quantifying how the environment modulates genetic effects on human quantitative phenotypes presents unique challenges. Environmental covariates are complex and difficult to measure and control at the organismal level, as found in GWAS and epidemiological studies. An alternative approach focuses on the cellular environment using in vitro treatments as a proxy for the organismal environment. These cellular environments simplify the organism-level environmental exposures to provide a tractable influence on subcellular phenotypes, such as gene expression. Expression quantitative trait loci (eQTL) mapping studies identified GxE interactions in response to drug treatment and pathogen exposure. However, eQTL mapping approaches are infeasible for large-scale analysis of multiple cellular environments. Recently, allele-specific expression (ASE) analysis emerged as a powerful tool to identify GxE interactions in gene expression patterns by exploiting naturally occurring environmental exposures. Here we characterized genetic effects on the transcriptional response to 50 treatments in five cell types. We discovered 1455 genes with ASE (FDR < 10%) and 215 genes with GxE interactions. We demonstrated a major role for GxE interactions in complex traits. Genes with a transcriptional response to environmental perturbations showed sevenfold higher odds of being found in GWAS. Additionally, 105 genes that indicated GxE interactions (49%) were identified by GWAS as associated with complex traits. Examples include GIPR-caffeine interaction and obesity and include LAMP3-selenium interaction and Parkinson disease. Our results demonstrate that comprehensive catalogs of GxE interactions are indispensable to thoroughly annotate genes and bridge epidemiological and genome-wide association studies. Show less

To explore the genetic basis and phenotypic correlation with disease severity in a large cohort of Chinese patients with hypertrophic cardiomyopathy (HCM). A total of 179 unrelated Chinese HCM patients admitted to our department from 2002 to 2011 were enrolled in this study. Direct gene sequencing of β-myosin heavy chain (MYH7), myosin binding protein-C ( MYBPC3), and cardiac troponin T (TNNT2) were performed and clinical data were obtained in these patients. A total of 34 mutations were identified in 40 patients (22.3%), 79.4% (27/34) mutations occurred only once and a possible hot spot, A26 in MYH7, was found. Distribution of mutations was 52.9% (18/34) (MYBPC3), 35.3% (12/34) ( MYH7) and 11.8% (4/34) (TNNT2) respectively. Double mutations were identified in 2.2% (4/179) patients. Genotype-positive patients were associated with an earlier symptom onset, severer left ventricular hypertrophy, a higher incidence of syncope, and were more likely to have positive family history of HCM or sudden cardiac death (SCD) , and were more likely to progress into heart failure (24.2% vs. 5.0%, P = 0.002) and at a higher risk of SCD (9.1% vs. 0, P = 0.009) during the 6.5-year follow-up. No statistical difference in any clinical parameters and outcomes was found between patients carrying MYBPC3 and MYH7 mutations. Double mutations were associated with malignant clinical progression in this cohort. Different phenotype severity could be seen in HCM patients with same genotype (e. g. MYH7-1736T, TNNT2-R92W). MYBPC3 is the most predominant gene mutation in this HCM cohort. The presence of a sarcomere mutation in patients with HCM is associated with poor clinical outcome, although no specific genes or mutations can exactly predict the severity of clinical phenotypes. Show less

Glucose-dependent insulinotropic polypeptide (GIP), an incretin hormone secreted from gastrointestinal K cells in response to food intake, has an important role in the control of whole-body metabolism. GIP signals through activation of the GIP receptor (GIPR), a G-protein-coupled receptor (GPCR). Dysregulation of this pathway has been implicated in the development of metabolic disease. Here we demonstrate that GIPR is constitutively trafficked between the plasma membrane and intracellular compartments of both GIP-stimulated and unstimulated adipocytes. GIP induces a downregulation of plasma membrane GIPR by slowing GIPR recycling without affecting internalization kinetics. This transient reduction in the expression of GIPR in the plasma membrane correlates with desensitization to the effects of GIP. A naturally occurring variant of GIPR (E354Q) associated with an increased incidence of insulin resistance, type 2 diabetes, and cardiovascular disease in humans responds to GIP stimulation with an exaggerated downregulation from the plasma membrane and a delayed recovery of GIP sensitivity following cessation of GIP stimulation. This perturbation in the desensitization-resensitization cycle of the GIPR variant, revealed in studies of cultured adipocytes, may contribute to the link of the E354Q variant to metabolic disease. Show less

Retinitis pigmentosa (RP) is a devastating form of retinal degeneration, with significant social and professional consequences. Molecular genetic information is invaluable for an accurate clinical diagnosis of RP due to its high genetic and clinical heterogeneity. Using a gene capture panel that covers 163 of the currently known retinal disease genes, including 48 RP genes, we performed a comprehensive molecular screening in a collection of 123 RP unsettled probands from a wide variety of ethnic backgrounds, including 113 unrelated simplex and 10 autosomal recessive RP (arRP) cases. As a result, 61 mutations were identified in 45 probands, including 38 novel pathogenic alleles. Interestingly, we observed that phenotype and genotype were not in full agreement in 21 probands. Among them, eight probands were clinically reassessed, resulting in refinement of clinical diagnoses for six of these patients. Finally, recessive mutations in CLN3 were identified in five retinal degeneration patients, including four RP probands and one cone-rod dystrophy patient, suggesting that CLN3 is a novel non-syndromic retinal disease gene. Collectively, our results underscore that, due to the high molecular and clinical heterogeneity of RP, comprehensive screening of all retinal disease genes is effective in identifying novel pathogenic mutations and provides an opportunity to discover new genotype-phenotype correlations. Information gained from this genetic screening will directly aid in patient diagnosis, prognosis, and treatment, as well as allowing appropriate family planning and counseling. Show less

Hereditary multiple exostoses (HME) is an autosomal dominant disease. The classical paradigm of mutation screening seeks to relate alterations in the exostosin glycosyltransferase genes, EXT1 and EXT2, which are responsible for over 70% of HME cases. However, the pathological significance of the majority of these mutations is often unclear. In a Chinese family with HME, EXT1 and EXT2 genes were screened by direct sequencing. The consequence of a detected mutant was predicted by in silico analysis and confirmed by mRNA analysis. The EXT1 and EXT2 mRNA and protein levels and the HS patterns in the HME patients were compared with those in healthy controls. A heterozygous transition (c.743+1G>A) in the EXT2 gene, which co-segregated with the HME phenotype in this family, was identified. The G residue at position +1 in intron 4 of EXT2 was predicted to be a 5' donor splice site. The mRNA analysis revealed an alternative transcript with a cryptic splice site 5 bp downstream of the wild-type site, which harbored a premature stop codon. However, the predicted truncated protein was not detected by western blot analysis. Decay of the mutant mRNA was shown by clone sequencing and quantification analysis. The corresponding downregulation of the EXT2 mRNA will contribute to the abnormal EXT1/EXT2 ratio and HS pattern that were detected in the patients with HME. The heterozygous mutation c.743+1G>A in the EXT2 gene causes HME as a result of abnormal splicing, mRNA decay, and the resulting haploinsufficiency of EXT2. Show less

Known genetic loci explain only a small proportion of the familial relative risk of colorectal cancer (CRC). We conducted a genome-wide association study of CRC in East Asians with 14,963 cases and 31,945 controls and identified 6 new loci associated with CRC risk (P = 3.42 × 10(-8) to 9.22 × 10(-21)) at 10q22.3, 10q25.2, 11q12.2, 12p13.31, 17p13.3 and 19q13.2. Two of these loci map to genes (TCF7L2 and TGFB1) with established roles in colorectal tumorigenesis. Four other loci are located in or near genes involved in transcriptional regulation (ZMIZ1), genome maintenance (FEN1), fatty acid metabolism (FADS1 and FADS2), cancer cell motility and metastasis (CD9), and cell growth and differentiation (NXN). We also found suggestive evidence for three additional loci associated with CRC risk near genome-wide significance at 8q24.11, 10q21.1 and 10q24.2. Furthermore, we replicated 22 previously reported CRC-associated loci. Our study provides insights into the genetic basis of CRC and suggests the involvement of new biological pathways. Show less

Androgen receptor (AR), a member of nuclear hormone receptor, plays an essential role in the initiation and progression of prostate cancer (PCa). In the present study, by way of immunoprecipitation followed by mass spectrometry (IP/MS) system, we found that carbohydrate-responsive element-binding protein (Chrebp), a glucose sensor in normal and cancer cells, interacted with AR in LNCaP cells. The interaction was further confirmed by coimmunoprecipitation analysis. Besides, Chrebp is required for the optimal transcriptional activity of AR in promoting the transcription of the prostate-specific antigen (PSA) promoter and messenger RNA (mRNA) expression. Consistently, knockdown of Chrebp using small interfering RNA (siRNA) in LNCaP cells reduced endogenous PSA levels. Together, our study demonstrates that Chrebp interacts with AR and regulates its transcriptional activity. Show less

Multiple osteochondromas (MO) is an inherited skeletal disorder, and the molecular mechanism of MO remains elusive. Exome sequencing has high chromosomal coverage and accuracy, and has recently been successfully used to identify pathogenic gene mutations. In this study, exome sequencing followed by Sanger sequencing validation was first used to screen gene mutations in two representative MO patients from a Chinese family. After filtering the data from the 1000 Genome Project and the dbSNP database (build 132), the detected candidate gene mutations were further validated via Sanger sequencing of four other members of the same MO family and 200 unrelated healthy subjects. Immunohistochemisty and multiple sequence alignment were performed to evaluate the importance of the identified causal mutation. A novel frameshift mutation, c.1457insG at codon 486 of exon 6 of EXT1 gene, was identified, which truncated the glycosyltransferase domain of EXT1 gene. Multiple sequence alignment showed that codon 486 of EXT1 gene was highly conserved across various vertebrates. Immunohistochemisty demonstrated that the chondrocytes with functional EXT1 in MO were less than those in extragenetic solitary chondromas. The novel c.1457insG deleterious mutation of EXT1 gene reported in this study expands the causal mutation spectrum of MO, and may be helpful for prenatal genetic screening and early diagnosis of MO. Show less

Neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) are both major serosanguinous maculopathies among the Asian elderly. They are similar in phenotype. Genetic variants in high-density lipoprotein (HDL) pathway were discovered to be associated with AMD in two genome-wide association studies. In this study with a Chinese Han cohort, we investigated the impacts of these genetic variants on nAMD and PCV separately. The missense coding variants and previously identified variants at LIPC, ABCA1, CETP, LPL and FADS1 loci were genotyped in 157 nAMD patients, 250 PCV patients and 204 controls without any macular abnormality. The known variants in CFH, ARMS2 and near HTRA1 were also genotyped. Fasting serum cholesterol levels were determined. The variants in CFH, ARMS2 and near HTRA1 were strongly associated with both PCV (P < 10(-6), 10(-7) and 10(-7) respectively) and nAMD (P < 10(-6), 10(-16) and 10(-17) respectively). None of the studied HDL-related variants were significantly associated with nAMD. A missense variant in CETP, rs5882, was significantly associated with PCV (P = 2.73 × 10(-4)). The rs5882 GG genotype had a 3.53-fold (95% CI: 1.93-6.45) increased risk for PCV, and conferred a significantly lower serum HDL-cholesterol level for PCV patients than the AA genotype (P = 0.048). These results suggest the need to separate PCV from nAMD in association studies especially with Asian cohorts, and that the HDL pathway may involve in the pathogenesis of PCV and nAMD differently. Show less

Alzheimer's disease (AD) is associated with impaired Aβ degradation in the brain. Enhancing the process of Aβ clearance is an attractive potential AD therapy. Treatment with LXR agonists may reduce Aβ levels in vivo. However, the clinical potential of many LXR agonists is limited because of their nonselective actions on LXRα/β, which lead to undesired hepatic lipogenesis via LXRα-dependent pathways. In this study, ABCA1 up-regulators were identified from a series of flavonoids and were found to preferentially activate LXRβ and up-regulate expression of ABCA1 and apoE in different cell lines. Further investigations confirmed that these compounds facilitate intracellular Aβ clearance in Aβ-loaded BV2 cells. Administration of compound 19 reduced total brain Aβ and plaque burden in APP/PS1 double transgenic mice, associated with elevated ABCA1 and apoE expression. Compared with the nonselective LXR agonists, the active compounds reported here induced less accumulation of undesired lipids and triglycerides in HepG2 cells. Show less

Obesity is a disorder with a complex genetic etiology, and its epidemic is a worldwide problem. Although multiple genetic loci associated with body mass index, the most common measure of obesity, have been identified in European populations, few studies have focused on Asian populations. Here we report a genome-wide association study and replication studies with 62,245 east Asian subjects, which identified two new body mass index-associated loci in the CDKAL1 locus at 6p22 (rs2206734, P = 1.4 × 10(-11)) and the KLF9 locus at 9q21 (rs11142387, P = 1.3 × 10(-9)), as well as several previously reported loci (the SEC16B, BDNF, FTO, MC4R and GIPR loci, P < 5.0 × 10(-8)). We subsequently performed gene-gene interaction analyses and identified an interaction (P = 2.0 × 10(-8)) between a SNP in the KLF9 locus (rs11142387) and one in the MSTN (also known as GDF8) locus at 2q32 (rs13034723). These findings should provide useful insights into the etiology of obesity. Show less

Multiple genetic loci associated with obesity or body mass index (BMI) have been identified through genome-wide association studies conducted predominantly in populations of European ancestry. We performed a meta-analysis of associations between BMI and approximately 2.4 million SNPs in 27,715 east Asians, which was followed by in silico and de novo replication studies in 37,691 and 17,642 additional east Asians, respectively. We identified ten BMI-associated loci at genome-wide significance (P < 5.0 × 10(-8)), including seven previously identified loci (FTO, SEC16B, MC4R, GIPR-QPCTL, ADCY3-DNAJC27, BDNF and MAP2K5) and three novel loci in or near the CDKAL1, PCSK1 and GP2 genes. Three additional loci nearly reached the genome-wide significance threshold, including two previously identified loci in the GNPDA2 and TFAP2B genes and a newly identified signal near PAX6, all of which were associated with BMI with P < 5.0 × 10(-7). Findings from this study may shed light on new pathways involved in obesity and demonstrate the value of conducting genetic studies in non-European populations. Show less

Apolipoproteins have recently been implicated in the etiology of Alzheimer's disease (AD). In particular, Apolipoprotein J (ApoJ or clusterin) has been proposed as a biomarker of the disease at the pre-dementia stage. We examined a group of apolipoproteins, including ApoA1, ApoA2, ApoB, ApoC3, ApoE, ApoH and ApoJ, in the plasma of a longitudinal community based cohort. 664 subjects (257 with Mild Cognitive Impairment [MCI] and 407 with normal cognition), mean age 78 years, from the Sydney Memory and Aging Study (MAS) were followed up over two years. Plasma apolipoprotein levels at baseline (Wave 1) were measured using a multiplex bead fluorescence immunoassay technique. At Wave 1, MCI subjects had lower levels of ApoA1, ApoA2 and ApoH, and higher levels of ApoE and ApoJ, and a higher ApoB/ApoA1 ratio. Carriers of the apolipoprotein E ε4 allele had significantly lower levels of plasma ApoE, ApoC3 and ApoH and a significantly higher level of ApoB. Global cognitive scores were correlated positively with ApoH and negatively with ApoJ levels. ApoJ and ApoE levels were correlated negatively with grey matter volume and positively with cerebrospinal fluid (CSF) volume on MRI. Lower ApoA1, ApoA2 and ApoH levels, and higher ApoB/ApoA1 ratio, increased the risk of cognitive decline over two years in cognitively normal individuals. ApoA1 was the most significant predictor of decline. These associations remained after statistically controlling for lipid profile. Higher ApoJ levels predicted white matter atrophy over two years. Elderly individuals with MCI have abnormal apolipoprotein levels, which are related to cognitive function and volumetric MRI measures cross-sectionally and are predictive of cognitive impairment in cognitively normal subjects. ApoA1, ApoH and ApoJ are potential plasma biomarkers of cognitive decline in non-demented elderly individuals. Show less

Nest breakdown and primordial folliculogenesis of the mouse ovary can be inhibited by progesterone (P4) and Notch signaling inhibitors. However, the relationship between these two signals during this process remains unknown. In the present study, transcript levels of Jagged2, Notch1, and their target, Hey2, increased markedly in ovaries during the beginning stage of folliculogenesis (17.5 days post coitus (dpc) to birth). Maternal P4 levels decreased simultaneously. We found that maternal midpregnancy P4 levels significantly inhibited Jagged2, Notch1, and Hey2 expression, and follicle formation in vitro. Maintaining high maternal P4 levels by daily injection also significantly suppressed the expression of Jagged2, Notch1, and Hey2, and follicle formation during late pregnancy. Based on immunohistochemistry, Jagged2 was localized in oocytes and Notch1 was strongly stained in pre-granulosa cells in 19.5 dpc ovaries. Suppression of their function by antibody addition and RNAi markedly inhibited nest breakdown and follicle formation. Taken together, these results demonstrate that maternal P4 levels during midpregnancy can inhibit the expression of Jagged2 and Notch1, which are involved in primordial folliculogenesis, in the mouse fetal ovary. Show less

The use of LINGO-1 antagonists to promote repair of damaged myelin is an emerging therapeutic opportunity for treatment of CNS diseases caused by demyelination such as multiple sclerosis. The Li33 anti-LINGO-1 antibody is a potent inducer of myelination in vitro and in vivo, but aggregation issues prevented the engineering of an optimal development candidate. PEGylated Li33 Fab' is one of several versions of the Li33 antibody that is being investigated in an attempt to identify the most favorable anti-LINGO-1 antibody design. For targeted PEGylation, a Li33 Fab' construct was engineered with a single unpaired cysteine in the heavy-chain hinge sequence. The Fab' was expressed in CHO cells, purified, and PEGylated with 20 kDa methoxy-poly(ethylene glycol) maleimide using a reaction strategy optimized to improve the yield of the PEG-Fab'. Biochemical analysis of the Li33 PEG-Fab' verified the selectivity of the PEGylation reaction. The in vitro and in vivo attributes of the PEG-Fab' were benchmarked against a Li33 full antibody. Both the Li33 PEG-Fab' and intact antibody bound LINGO-1 with nanomolar affinity, promoted myelination in an in vitro signaling assay, and promoted the repair of damaged myelin in the rat lysolecithin model. These studies extend our understanding of the biological activity of the Li33 mAb and validate the use of an anti-LINGO-1 PEG-Fab' for treatment of CNS diseases caused by demyelination. Show less

Synthetic activators of peroxisome proliferator-activated receptors (PPARs) stimulate cholesterol removal from macrophages through PPAR-dependent up-regulation of liver × receptor α (LXRα) and subsequent induction of cholesterol exporters such as ATP-binding cassette transporter A1 (ABCA1) and scavenger receptor class B type 1 (SR-BI). The present study aimed to test the hypothesis that the hydroxylated derivative of linoleic acid (LA), 13-HODE, which is a natural PPAR agonist, has similar effects in RAW264.7 macrophages. RAW264.7 macrophages were treated without (control) or with LA or 13-HODE in the presence and absence of PPARα or PPARγ antagonists and determined protein levels of LXRα, ABCA1, ABCG1, SR-BI, PPARα and PPARγ and apolipoprotein A-I mediated lipid efflux. Treatment of RAW264.7 cells with 13-HODE increased PPAR-transactivation activity and protein concentrations of LXRα, ABCA1, ABCG1 and SR-BI when compared to control treatment (P < 0.05). In addition, 13-HODE enhanced cholesterol concentration in the medium but decreased cellular cholesterol concentration during incubation of cells with the extracellular lipid acceptor apolipoprotein A-I (P < 0.05). Pre-treatment of cells with a selective PPARα or PPARγ antagonist completely abolished the effects of 13-HODE on cholesterol efflux and protein levels of genes investigated. In contrast to 13-HODE, LA had no effect on either of these parameters compared to control cells. 13-HODE induces cholesterol efflux from macrophages via the PPAR-LXRα-ABCA1/SR-BI-pathway. Show less

Obesity is a well-established risk factor for endometrial cancer, the most common gynecologic malignancy. Recent genome-wide association studies (GWAS) have identified multiple genetic markers for obesity. The authors evaluated the association of obesity-related single nucleotide polymorphisms (SNPs) with endometrial cancer using GWAS data from their recently completed study, the Shanghai Endometrial Cancer Genetics Study, which comprised 832 endometrial cancer cases and 2,049 controls (1996-2005). Thirty-five SNPs previously associated with obesity or body mass index (BMI; weight (kg)/height (m)(2)) at a minimum significance level of ≤5 × 10(-7) in the US National Human Genome Research Institute's GWAS catalog (http://genome.gov/gwastudies) and representing 26 unique loci were evaluated by either direct genotyping or imputation. The authors found that for 22 of the 26 unique loci tested (84.6%), the BMI-associated risk variants were present at a higher frequency in cases than in population controls (P = 0.0003). Multiple regression analysis showed that 9 of 35 BMI-associated variants, representing 7 loci, were significantly associated (P ≤ 0.05) with the risk of endometrial cancer; for all but 1 SNP, the direction of association was consistent with that found for BMI. For consistent SNPs, the allelic odds ratios ranged from 1.15 to 1.29. These 7 loci are in the SEC16B/RASAL, TMEM18, MSRA, SOX6, MTCH2, FTO, and MC4R genes. The associations persisted after adjustment for BMI, suggesting that genetic markers of obesity provide value in addition to BMI in predicting endometrial cancer risk. Show less

Hereditary multiple exostoses (HME) is an autosomal dominant bone disorder characterized by growth of benign multiple exostoses. In our present study, we describe a four-generation Han Chinese kindred with eight members affected by HME. Haplotyping analysis and mutation detection was performed. The results linked the disease-causing gene to the EXT1 locus on chromosome 8. A novel mutation in EXT1, c.1897delC, which cosegregated with the disease phenotype, was detected. To further confirm this mutation, a mismatch primer was designed to introduce a ScaI restriction site into the normal allele by polymerase chain reaction, and the following restriction fragment length polymorphism analysis demonstrated that the mutation was not detected in any unaffected individuals of the family or 100 unrelated Han Chinese control individuals. This mutation leads to a frameshift from codon 633, resulting in a premature termination at codon 642 and loss of the highly conserved C terminal region of the protein. Therefore, this heterozygous mutation must be classified as pathogenic and can be regarded as the cause of HME in this Chinese family. Show less

Recent genome-wide association (GWA) studies have identified 18 genetic loci for obesity. Using directly observed and imputed GWA genotyping data on approximately 5,000 Chinese women (1996-2007), the authors evaluated 17 single nucleotide polymorphisms (SNPs) that represent 17 distinct obesity loci. Two SNPs near the BAT2 and MC4R genes and 3 SNPs within the FTO, SEC16B, and SH2B1 genes were significantly associated with body mass index (weight (kg)/height (m)(2)), body weight, and the prevalence of obesity. The per-allele increase in body mass index ranged from 0.16 units (BAT2) to 0.38 units (SH2B1). Odds ratios for obesity ranged from 1.46 (95% confidence interval (CI): 1.12, 1.92) for BAT2 to 2.16 (95% CI: 1.39, 3.37) for MC4R. A genetic risk score calculated by summing the number of risk-increasing alleles that each woman carried at these 5 loci was significantly associated with the prevalence of obesity. Women carrying 5 or more risk alleles had a 3.13-fold (95% CI: 2.06, 4.77) higher prevalence of obesity than women carrying 1 or no risk alleles. Results from this study extend some previous GWA findings to Chinese women and show the need for additional studies to identify susceptibility loci in Chinese and other Asian populations. Show less

We have previously mapped a major susceptibility locus influencing familial lung cancer risk to chromosome 6q23-25. However, the causal gene at this locus remains undetermined. In this study, we further refined this locus to identify a single candidate gene, by fine mapping using microsatellite markers and association studies using high-density single nucleotide polymorphisms (SNP). Six multigenerational families with five or more affected members were chosen for fine-mapping the 6q linkage region using microsatellite markers. For association mapping, we genotyped 24 6q-linked cases and 72 unrelated noncancer controls from the Genetic Epidemiology of Lung Cancer Consortium resources using the Affymetrix 500K chipset. Significant associations were validated in two independent familial lung cancer populations: 226 familial lung cases and 313 controls from the Genetic Epidemiology of Lung Cancer Consortium, and 154 familial cases and 325 controls from Mayo Clinic. Each familial case was chosen from one high-risk lung cancer family that has three or more affected members. A region-wide scan across 6q23-25 found significant association between lung cancer susceptibility and three single nucleotide polymorphisms in the first intron of the RGS17 gene. This association was further confirmed in two independent familial lung cancer populations. By quantitative real-time PCR analysis of matched tumor and normal human tissues, we found that RGS17 transcript accumulation is highly and consistently increased in sporadic lung cancers. Human lung tumor cell proliferation and tumorigenesis in nude mice are inhibited upon knockdown of RGS17 levels. RGS17 is a major candidate for the familial lung cancer susceptibility locus on chromosome 6q23-25. Show less

Apolipoprotein A5 gene (APOA5) has been shown to modulate plasma triglyceride concentrations. We investigated 2 distinct APOA1/C3/A5 haplotypes roles for hypertriglyceridemia. We recruited 308 cases of hypertriglyceridemia and 281 normal controls from a hospital. Twelve single nucleotide polymorphisms (SNPs) across the APOA1/C3/A5 gene region were genotyped. One haplotype containing the minor alleles of the APOA5 (-1131T>C, c.553G>T) and APOA1 (-3013C>T,-75G>A) was more prevalent in cases than in controls (11.3% vs. 1.1%, respectively) and was statistically significantly associated with high triglycerides (adjusted odds ratio: 12.83, 95% confidence interval [CI]: 5.1-32.4, P<0.001). Another haplotype that was associated with hypertriglyceridemia (adjusted odds ratio 2.13, 95% CI, 1.37-3.29, P=0.001). Participants carrying both minor alleles of APOA5-1131CC and c.553TT had a 116% higher triglyceride concentration compared with those carrying common allele. The APOA1/C3/A5 haplotype represents an important locus for predicting risk of hypertriglyceridemia among Taiwanese. Show less

Synthetic activators of peroxisome proliferator-activated receptors (PPAR)-alpha and -gamma are capable of reducing macrophage foam cell cholesterol accumulation through the activation of genes involved in cholesterol homeostasis. Since conjugated linoleic acids (CLA) were also demonstrated to activate PPARalpha and PPARgamma in vivo and in vitro, we tested the hypothesis that CLA are also capable of reducing macrophage foam cell cholesterol accumulation. Thus, mouse RAW264.7 macrophage-derived foam cells were treated with CLA isomers, c9t11-CLA and t10c12-CLA, and linoleic acid (LA), as reference fatty acid, and analyzed for the concentrations of free and esterified cholesterol, cholesterol efflux and expression of genes involved in cholesterol homeostasis (CD36, ABCA1, LXRalpha, NPC-1, and NPC-2). Treatment with c9t11-CLA and t10c12-CLA, but not LA, lowered cholesterol accumulation, stimulated acceptor-dependent cholesterol efflux, and increased relative mRNA concentrations of CD36, ABCA1, LXRalpha, NPC-1, and NPC-2 (P < 0.05). In conclusion, the present study showed that CLA isomers reduce cholesterol accumulation in RAW264.7 macrophage-derived foam cells presumably by enhancing lipid acceptor-dependent cholesterol efflux. Show less

The purpose of this study was to explore the frequency of apolipoprotein A5 (APOA5) -1131T/C polymorphism in Zhenjiang and its effects on lipid metabolism and insulin resistance in type II diabetes mellitus(DM) patients. The genotypes of APOA5 -1131T/C polymorphism were determined in 152 healthy individuals and 71 type II DM patients by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum levels of lipids, glucose and insulin in these subjects were also estimated by biochemical methods. The frequency of the APOA5-1131C allele in DM patients was significantly higher than that of the control group (0.430 vs 0.296, P = 0.006). When compared with the TT genotype, CC homozygotes had a significantly increased DM risk (OR=3.75, 95% CI: 1.57-8.92). In the DM group, the serum levels of triglyceride (TG) of C carriers (TC+CC) were significantly higher than those of non-C carriers (TT) (P 0.01), and serum levels of total cholesterol (TC) and low density lipoprotein cholesterol(LDL-c) in subjects with the CC genotype were also significantly higher than those with the TT genotype (P 0.05). However, there was no significance in profiles of insulin resistance in various genotypes in both groups. The APOA5 single nucleotide polymorphism was associ-ated with serum TG level in the population. The -1131C allele contributed to the increase of serum levels of TG, TC and LDL-c and but had no effect on profiles of insulin resistance in DM patients. The APOA5 -1131C allele may be associated with increased susceptibility to type II diabetes mellitus. Show less

Several independent population studies have reported that c.553G>T polymorphism of the apolipoprotein A5 gene (APOA5) is associated with hypertriglyceridaemia. The aim of this study is to investigate the association between this genetic variation and the risk of type 2 diabetes mellitus. In this study, APOA5 c.553G>T polymorphisms in 152 healthy individuals and 71 type 2 diabetes mellitus patients were detected by PCR-restriction fragment length polymorphism and agarose electrophoresis methods, and serum levels of lipids were also estimated by biochemical methods. The frequency of T alleles in the diabetes and control groups was 0.085 and 0.049, respectively. Compared with controls, there was no significant difference in the distribution of genotype and allele frequencies of c.553G>T polymorphic sites in diabetic patients (p=0.27 and p=0.15, respectively). However, the frequency of GT and TT genotypes and the T allele in the subgroup with hypertriglyceridaemia was significantly higher than that in the subgroup with normal triglyceridaemia in both the control group (p=0.034 and p=0.014, respectively) and the diabetes group (p=0.037 and p=0.007, respectively). In the diabetes and control groups, triglyceride levels in (GT+TT) genotype individuals were significantly higher than in GG genotype individuals (p=0.001 and p=0.003, respectively), and levels of low-density lipoprotein cholesterol were also significantly higher (p=0.044 and p=0.022, respectively). APOA5 c.553G>T polymorphism is not significantly associated with susceptibility to type 2 diabetes mellitus, but is associated with plasma triglyceride and low-density lipoprotein cholesterol levels. Show less