To study the effects of Jiangzhi Granule (JZG), a compound traditional Chinese herbal medicine, in regulating liver X receptor α (LXRα) and sterol regulatory element-binding protein-1c (SREBP-1c) expr Show more
To study the effects of Jiangzhi Granule (JZG), a compound traditional Chinese herbal medicine, in regulating liver X receptor α (LXRα) and sterol regulatory element-binding protein-1c (SREBP-1c) expressions in a rat model of non-alcoholic fatty liver disease (NAFLD). Forty specific pathogen-free Wistar male rats were randomly divided into normal group, untreated group, pioglitazone (PIO) group and JZG group. All rats were fed with high-fat diet (88% normal chow plus 10% lard plus 2% cholesterol) for 4 weeks except for the normal group. After the NAFLD model was established, PIO and JZG were fed to rats in the corresponding groups respectively for another 4 weeks. At the end of the 8th week, liver steatosis level was observed under a light microscope with hematoxylin and eosin (HE) staining; serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and triacylglycerol (TAG) and free fatty acid (FFA) contents in liver tissues were measured. LXRα and SREBP-1c expressions in liver tissues were determined by real-time polymerase chain reaction and Western blot methods. Compared with the normal group, there were physiological changes for hepatic steatosis in liver tissues in the untreated group as observed by HE staining. JZG improved serum ALT and AST levels which were significantly increased in the untreated group. Both JZG and PIO improved FFA and TAG levels in liver tissues which were significantly increased in the untreated group. mRNA and protein levels of LXRα and SREBP-1c in the untreated group were higher than those in the normal group, while the treatment of JZG and PIO lowered their expressions. JZG may regulate fatty acid metabolic disorder by decreasing the levels of LXRα and SREBP-1c. Show less
In the previous experiment, we found that there was a different response between E3 rats and DA.1U rats to high-fat-diet-induced metabolic syndrome (HFD-MetS). The aim of this study was to explore the Show more
In the previous experiment, we found that there was a different response between E3 rats and DA.1U rats to high-fat-diet-induced metabolic syndrome (HFD-MetS). The aim of this study was to explore the cause and molecular mechanism of the genetic difference in susceptibility to metabolic syndrome in E3 rats as compared with DA.1U rats. Firstly, a 12-week HFD-MetS model in E3 and DA.1U rats was carried out and assessed. Then, the expression of key insulin signaling molecules, metabolic nuclear receptors, metabolic key enzymes and histone deacetylases (Hdacs) was determined by different methods. Finally, the effects of overexpression and disruption of Hdac3 on metabolic nuclear receptors were analyzed in CBRH-7919 cells and primarily-hepatic cells from DA.1U and E3 rats. We found that E3 rats were susceptible, while DA.1U rats were resisted to HFD-MetS. The expression of liver X receptor α,β (LXR-α,β), farnesoid X receptor (FXR), peroxisome proliferator activated receptor γ (PPAR-γ) and cholesterol 7α-hydroxylase (CYP7A1) increased markedly in DA.1U rat liver, whereas they decreased significantly in E3 rats. The expression of Hdac3 increased by HFD treatment in both E3 and DA.1U rat livers, but the constitutive Hdac3 expression was lower in DA.IU rat liver than in E3 rat liver. Importantly, overexpression of Hdac3 could downregulate the expression of LXR-α, PPAR-γ and CYP7A1 in both CBRH-7919 cells and primarily cultured hepatic cells from DA.IU rats. On the contrary, disruption of Hdac3 by shRNA upregulated the expression of LXR-α, PPAR-γ and CYP7A1 in both CBRH-7919 cells and primarily cultured hepatic cells from E3 rats. The results suggested that a high constitutive expression of Hdac3 inhibiting the expression of PPAR-γ, LXR-α and CYP7A1 in liver contributes to HFD-MetS in E3 rats. Show less
Liver X receptors (LXRs) are implicated in the regulation of cholesterol homeostasis, inflammatory response and atherogenesis. Administration of LXR agonists inhibits the progress of atherosclerosis, Show more
Liver X receptors (LXRs) are implicated in the regulation of cholesterol homeostasis, inflammatory response and atherogenesis. Administration of LXR agonists inhibits the progress of atherosclerosis, and also increases plasma triglyceride levels, representing an obstacle to their use in treating this disease. The objective of this study was to develop an alternative approach that could overcome this obstacle. Eight-week-old low-density lipoprotein receptor-deficient (LDLR(-/-)) mice were transplanted with hematopoietic stem cell (HSC)-enriched bone marrow cells transduced with lentivectors expressing either green fluorescent protein (GFP) (Lenti-SP-GFP, control) or LXRα (Lenti-SP-LXRα) driven by a synthetic macrophage promoter. At 4 weeks post-transplant, the mice were fed with a Western diet for 8 weeks and then killed. Compared with Lenti-SP-GFP mice, the Lenti-SP-LXRα mice had a 30% reduction in atherosclerotic lesions, which was accompanied by increases in levels of macrophage expression of cholesterol efflux genes apolipoprotein E and ATP-binding cassette A1, as well as decreases in plasma inflammatory cytokines interleukin-6 and tumor necrosis factor-α. Intriguingly, a 50% reduction of plasma triglyceride level was also observed. We conclude that HSC-based macrophage LXRα gene therapy ameliorates the development of atherosclerosis along with an unexpected concomitant reduction of plasma triglyceride levels in LDLR(-/-) mice. These findings highlight the potential value of macrophage LXR expression as an avenue for therapeutic intervention against atherosclerosis. Show less
The nuclear receptor liver X receptor (LXR) is a ligand-dependent transcription factor that plays an important role in the metabolism and homeostasis of cholesterol, lipids, bile acids, and steroid ho Show more
The nuclear receptor liver X receptor (LXR) is a ligand-dependent transcription factor that plays an important role in the metabolism and homeostasis of cholesterol, lipids, bile acids, and steroid hormones. MicroRNAs (miRNAs) are recently recognized important negative regulators of gene expression. In this report, we showed that miRNA hsa-miR-613 played an important role in the autoregulation of the human LXRα gene. hsa-miR-613 targeted the endogenous LXRα through its specific miRNA response element (613MRE) within the LXRα 3'-untranslated region. Interestingly and paradoxically, the expression of hsa-miR-613 itself was induced upon the activation of LXR. However, hsa-miR-613 did not appear to be a direct LXR target gene. Instead, the positive regulation of hsa-miR-613 by LXR was mediated by the sterol regulatory element binding protein (SREBP)-1c, a known LXR target gene. Promoter analysis revealed an SREBP response element in the hsa-miR-613 gene promoter. Treatment with insulin also induced the expression of hsa-miR-613 in an SREBP-1c-dependent manner, further supporting the role of SREBP-1c in the positive regulation of this miRNA species. Finally, the autoinduction of LXRα by a LXR agonist was enhanced when hsa-miR-613 was inhibited or SREBP-1c was down-regulated. hsa-miR-613 appeared to specifically target the human LXRα. We propose that the negative regulation mediated by hsa-miR-613 and SREBP-1c and the previously reported positive regulation mediated by an LXR response element in the LXRα gene promoter constitute a ying-yang mechanism to ensure a tight regulation of this nuclear receptor of many metabolic functions. Show less
The nuclear receptor retinoid X receptor (RXR) functions potently in the regulation of homeostasis and cell development, while rexinoids as RXR agonists have proved their therapeutic potential in the Show more
The nuclear receptor retinoid X receptor (RXR) functions potently in the regulation of homeostasis and cell development, while rexinoids as RXR agonists have proved their therapeutic potential in the treatment of metabolic diseases and cancer. Here, the natural product bigelovin was identified as a selective RXRα agonist. Interestingly, this compound could not transactivate RXRα:RXRα homodimer but could enhance the transactivation of RXRα:peroxisome proliferator-activated receptor γ heterodimer and repress that of RXRα:liver X receptor (LXR) α heterodimer, while it had no effects on RXRα:farnesoid X receptor heterodimer. Considering that the effective role of LXR response element involved transactivation of sterol regulatory element-binding protein-1c mediated by RXRα:LXRα in triglyceride elevation, such LXR response element repressing by bigelovin has obviously addressed its potency for further research. Moreover, our determined crystal structure of the bigelovin-activated RXRα ligand-binding domain with the coactivator human steroid receptor coactivator-1 peptide revealed that bigelovin adopted a distinct binding mode. Compared with the known RXR ligands, bigelovin lacks the acidic moiety in structure, which indicated that the acidic moiety rendered little effects on RXR activation. Our results have thereby provided new insights into the structure-based selective rexinoids design with bigelovin as a potential lead compound. Show less
Although widely prescribed for their potent antiinflammatory actions, glucocorticoid drugs (e.g., dexamethasone) cause undesirable side effects that are features of the metabolic syndrome, including h Show more
Although widely prescribed for their potent antiinflammatory actions, glucocorticoid drugs (e.g., dexamethasone) cause undesirable side effects that are features of the metabolic syndrome, including hyperglycemia, fatty liver, insulin resistance, and type II diabetes. Liver x receptors (LXRs) are nuclear receptors that respond to cholesterol metabolites and regulate the expression of a subset of glucocorticoid target genes. Here, we show LXRβ is required to mediate many of the negative side effects of glucocorticoids. Mice lacking LXRβ (but not LXRα) were resistant to dexamethasone-induced hyperglycemia, hyperinsulinemia, and hepatic steatosis, but remained sensitive to dexamethasone-dependent repression of the immune system. In vivo, LXRα/β knockout mice demonstrated reduced dexamethasone-induced expression of the key hepatic gluconeogenic gene, phosphoenolpyruvate carboxykinase (PEPCK). In perfused liver and primary mouse hepatocytes, LXRβ was required for glucocorticoid-induced recruitment of the glucocorticoid receptor to the PEPCK promoter. These findings suggest a new avenue for the design of safer glucocorticoid drugs through a mechanism of selective glucocorticoid receptor transactivation. Show less
Obesity is a serious health concern for children and adolescents, particularly in Western societies, where its incidence is now considered to have reached epidemic proportions. A number of genetic det Show more
Obesity is a serious health concern for children and adolescents, particularly in Western societies, where its incidence is now considered to have reached epidemic proportions. A number of genetic determinants of adult BMI have already been established through genome wide association studies (GWAS), most recently from the GIANT meta-analysis of such datasets combined. In this current study of European Americans, we examined the 32 loci detected in that GIANT study in the context of common childhood obesity within a cohort of 1,097 cases (defined as BMI ≥95th percentile), together with 2,760 lean controls (defined as BMI <50th percentile), aged between 2 and 18 years old. Nine of these single-nucleotide polymorphims (SNPs) yielded at least nominal evidence for association with common childhood obesity, namely at the FTO, TMEM18, NRXN3, MC4R, SEC16B, GNPDA2, TNNI3K, QPCTL, and BDNF loci. However, overall 28 of the 32 loci showed directionally consistent effects to that of the adult BMI meta-analysis. We conclude that among the 32 loci that have been reported to associate with adult BMI in the largest meta-analysis of BMI to date, at least nine also contribute to the determination of common obesity in childhood in European Americans, as demonstrated by their associations in our pediatric cohort. Show less
Large-scale genome-wide association studies (GWAS) have identified many loci associated with body mass index (BMI), but few studies focused on obesity as a binary trait. Here we report the results of Show more
Large-scale genome-wide association studies (GWAS) have identified many loci associated with body mass index (BMI), but few studies focused on obesity as a binary trait. Here we report the results of a GWAS and candidate SNP genotyping study of obesity, including extremely obese cases and never overweight controls as well as families segregating extreme obesity and thinness. We first performed a GWAS on 520 cases (BMI>35 kg/m(2)) and 540 control subjects (BMI<25 kg/m(2)), on measures of obesity and obesity-related traits. We subsequently followed up obesity-associated signals by genotyping the top ∼500 SNPs from GWAS in the combined sample of cases, controls and family members totaling 2,256 individuals. For the binary trait of obesity, we found 16 genome-wide significant signals within the FTO gene (strongest signal at rs17817449, P = 2.5 × 10(-12)). We next examined obesity-related quantitative traits (such as total body weight, waist circumference and waist to hip ratio), and detected genome-wide significant signals between waist to hip ratio and NRXN3 (rs11624704, P = 2.67 × 10(-9)), previously associated with body weight and fat distribution. Our study demonstrated how a relatively small sample ascertained through extreme phenotypes can detect genuine associations in a GWAS. Show less
To infer the causal association between childhood BMI and age at menarche, we performed a mendelian randomisation analysis using twelve established "BMI-increasing" genetic variants as an instrumental Show more
To infer the causal association between childhood BMI and age at menarche, we performed a mendelian randomisation analysis using twelve established "BMI-increasing" genetic variants as an instrumental variable (IV) for higher BMI. In 8,156 women of European descent from the EPIC-Norfolk cohort, height was measured at age 39-77 years; age at menarche was self-recalled, as was body weight at age 20 years, and BMI at 20 was calculated as a proxy for childhood BMI. DNA was genotyped for twelve BMI-associated common variants (in/near FTO, MC4R, TMEM18, GNPDA2, KCTD15, NEGR1, BDNF, ETV5, MTCH2, SEC16B, FAIM2 and SH2B1), and for each individual a "BMI-increasing-allele-score" was calculated by summing the number of BMI-increasing alleles across all 12 loci. Using this BMI-increasing-allele-score as an instrumental variable for BMI, each 1 kg/m(2) increase in childhood BMI was predicted to result in a 6.5% (95% CI: 4.6-8.5%) higher absolute risk of early menarche (before age 12 years). While mendelian randomisation analysis is dependent on a number of assumptions, our findings support a causal effect of BMI on early menarche and suggests that increasing prevalence of childhood obesity will lead to similar trends in the prevalence of early menarche. Show less
Genome-wide sequencing studies in breast cancer have recently identified frequent mutations in the zinc finger protein 668 (ZNF668), the function of which is undefined. Here, we report that ZNF668 is Show more
Genome-wide sequencing studies in breast cancer have recently identified frequent mutations in the zinc finger protein 668 (ZNF668), the function of which is undefined. Here, we report that ZNF668 is a nucleolar protein that physically interacts with and regulates p53 and its negative regulator MDM2. Through MDM2 binding, ZNF668 regulated autoubiquitination of MDM2 and its ability to mediate p53 ubiquitination and degradation. ZNF668 deficiency also impaired DNA damage-induced stabilization of p53. RNA interference-mediated knockdown of ZNF668 was sufficient to transform normal mammary epithelial cells. ZNF668 effectively suppressed breast cancer cell proliferation in vitro and tumorigenicity in vivo. Taken together, our studies identify ZNF668 as a novel breast tumor suppressor gene that functions in regulating p53 stability. Show less
Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between bod Show more
Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ∼ 2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10⁻⁸), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation. Show less
Glucose levels 2 h after an oral glucose challenge are a clinical measure of glucose tolerance used in the diagnosis of type 2 diabetes. We report a meta-analysis of nine genome-wide association studi Show more
Glucose levels 2 h after an oral glucose challenge are a clinical measure of glucose tolerance used in the diagnosis of type 2 diabetes. We report a meta-analysis of nine genome-wide association studies (n = 15,234 nondiabetic individuals) and a follow-up of 29 independent loci (n = 6,958-30,620). We identify variants at the GIPR locus associated with 2-h glucose level (rs10423928, beta (s.e.m.) = 0.09 (0.01) mmol/l per A allele, P = 2.0 x 10(-15)). The GIPR A-allele carriers also showed decreased insulin secretion (n = 22,492; insulinogenic index, P = 1.0 x 10(-17); ratio of insulin to glucose area under the curve, P = 1.3 x 10(-16)) and diminished incretin effect (n = 804; P = 4.3 x 10(-4)). We also identified variants at ADCY5 (rs2877716, P = 4.2 x 10(-16)), VPS13C (rs17271305, P = 4.1 x 10(-8)), GCKR (rs1260326, P = 7.1 x 10(-11)) and TCF7L2 (rs7903146, P = 4.2 x 10(-10)) associated with 2-h glucose. Of the three newly implicated loci (GIPR, ADCY5 and VPS13C), only ADCY5 was found to be associated with type 2 diabetes in collaborating studies (n = 35,869 cases, 89,798 controls, OR = 1.12, 95% CI 1.09-1.15, P = 4.8 x 10(-18)). Show less
mAKAPbeta is the scaffold for a multimolecular signaling complex in cardiac myocytes that is required for the induction of neonatal myocyte hypertrophy. We now show that the pro-hypertrophic phosphata Show more
mAKAPbeta is the scaffold for a multimolecular signaling complex in cardiac myocytes that is required for the induction of neonatal myocyte hypertrophy. We now show that the pro-hypertrophic phosphatase calcineurin binds directly to a single site on mAKAPbeta that does not conform to any of the previously reported consensus binding sites. Calcineurin-mAKAPbeta complex formation is increased in the presence of Ca(2+)/calmodulin and in norepinephrine-stimulated primary cardiac myocytes. This binding is of functional significance because myocytes exhibit diminished norepinephrine-stimulated hypertrophy when expressing a mAKAPbeta mutant incapable of binding calcineurin. In addition to calcineurin, the transcription factor NFATc3 also associates with the mAKAPbeta scaffold in myocytes. Calcineurin bound to mAKAPbeta can dephosphorylate NFATc3 in myocytes, and expression of mAKAPbeta is required for NFAT transcriptional activity. Taken together, our results reveal the importance of regulated calcineurin binding to mAKAPbeta for the induction of cardiac myocyte hypertrophy. Furthermore, these data illustrate how scaffold proteins organizing localized signaling complexes provide the molecular architecture for signal transduction networks regulating key cellular processes. Show less
Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation at the synovial membrane. Although great progress has been made recently in exploring the etiology and pathogen Show more
Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation at the synovial membrane. Although great progress has been made recently in exploring the etiology and pathogenesis of RA, its molecular pathological mechanism remains to be further defined and it is still a great challenge in determining the diagnosis and in choosing the appropriate therapy in early patients. This study was performed to screen candidate RA-associated serum proteins by comparative proteomics to provide research clues to early diagnosis and treatment of RA. Sera isolated from 6 RA patients and 6 healthy volunteers were pooled respectively and high-abundance proteins were depleted by Plasma 7 Multiple Affinity Removal System. The protein expression profiles between the two groups were then compared by two-dimensional gel electrophoresis (2-DE) and the proteins over/under-expressed by more than 3-fold were identified by mass spectrometry analysis. To validate the differential expression levels of the identified proteins between the two groups, ELISA was performed in two of the identified proteins in individual sera from 32 RA patients and 32 volunteers. Eight proteins which over/under-expressed in sera of RA patients were identified. Among them, chain A of transthyretin (TTR) was under-expressed, while serum amyloid A protein, apolipoprotein A (ApoA)-IV, ApoA-IV precursor, haptoglobin 2, ceruloplasmin (Cp), immunoglobulin superfamily 22 and HT016 were over-expressed. ELISA test confirmed that Cp expressed remarkably higher while TTR obviously lower in RA group compared with volunteer group. There were 8 identified proteins differentially expressed between RA group and volunteer group, which might be candidate RA-associated proteins and might be promising diagnostic indicators or therapeutic targets for RA. Show less
Peroxisome proliferator-activated receptor (PPAR) γ coactivator-1β (PGC-1β) is a transcriptional coactivator that induces hypertriglyceridemia in response to dietary fats through activating hepatic li Show more
Peroxisome proliferator-activated receptor (PPAR) γ coactivator-1β (PGC-1β) is a transcriptional coactivator that induces hypertriglyceridemia in response to dietary fats through activating hepatic lipogenesis and lipoprotein secretion. The expression of PGC-1β is regulated by free fatty acids. Here we show that PGC-1β regulates plasma triglyceride metabolism through stimulating apolipoprotein C3 (APOC3) expression and elevating APOC3 levels in circulation. Remarkably, liver-specific knockdown of APOC3 significantly ameliorates PGC-1β-induced hypertriglyceridemia in mice. Hepatic expression of PGC-1β and APOC3 is reduced in response to acute and chronic treatments with nicotinic acid, a widely prescribed drug for lowering plasma triglycerides. Adenoviral-mediated knockdown of PGC-1β or APOC3 in the liver recapitulates the hypolipidemic effect of nicotinic acid. Proteomic analysis of hepatic PGC-1β transcriptional complex indicates that it stimulates APOC3 expression through coactivating orphan nuclear receptor ERRα and recruiting chromatin-remodeling cofactors. Together, these studies identify PGC-1β as an important regulator of the APOC3 gene cluster and reveal a mechanism through which nicotinic acid achieves its therapeutic effects. Show less
A central point of regulation in the Wnt/beta-catenin signalling pathway is the formation of the beta-catenin destruction complex. Axin1, an essential negative regulator of Wnt signalling, serves as a Show more
A central point of regulation in the Wnt/beta-catenin signalling pathway is the formation of the beta-catenin destruction complex. Axin1, an essential negative regulator of Wnt signalling, serves as a scaffold within this complex and is critical for rapid turnover of beta-catenin. To examine the mechanism by which Wnt signalling disables the destruction complex, we used an immunoprecipitation-coupled proteomics approach to identify novel endogenous binding partners of Axin1. We found mitogen-activated protein kinase kinase kinase 1 (MAP3K1) as an Axin1 interactor in Ls174T colorectal cancer (CRC) cells. Importantly, confirmation of this interaction in HEK293T cells indicated that the Axin1-MAP3K1 interaction is induced and modulated by Wnt stimulation. siRNA depletion of MAP3K1 specifically abrogated TCF/LEF-driven transcription and Wnt3A-driven endogenous gene expression in both HEK293T as well as DLD-1 CRC. Expression of ubiquitin ligase mutants of MAP3K1 abrogated TCF/LEF transcription, whereas kinase mutants had no effect in TCF-driven activity, highlighting the essential role of the MAP3K1 E3 ubiquitin ligase activity in regulation of the Wnt/beta-catenin pathway. These results suggest that MAP3K1, previously reported as an Axin1 inter-actor in c-Jun NH(2)-terminal kinase pathway, is also involved in the canonical Wnt signalling pathway and positively regulates expression of Wnt target genes. Show less
An important issue in epigenetic research is to understand how the numerous methylation marks associated with histone and certain nonhistone proteins are recognized and interpreted by the hundreds of Show more
An important issue in epigenetic research is to understand how the numerous methylation marks associated with histone and certain nonhistone proteins are recognized and interpreted by the hundreds of chromatin-binding modules (CBMs) in a cell to control chromatin state, gene expression, and other cellular functions. We have assembled a peptide chip that represents known and putative lysine methylation marks on histones and p53 and probed the chip for binding to a group of CBMs to obtain a comprehensive interaction network mediated by lysine methylation. Interactions revealed by the peptide array screening were validated by in-solution binding assays. This study not only recapitulated known interactions but also uncovered new ones. A novel heterochromatin protein 1 beta (HP1β) chromodomain-binding site on histone H3, H3K23me, was discovered from the peptide array screen and subsequently verified by mass spectrometry. Data from peptide pull-down and colocalization in cells suggest that, besides the H3K9me mark, H3K23me may play a role in facilitating the recruitment of HP1β to the heterochromatin. Extending the peptide array and mass spectrometric approach presented here to more histone marks and CBMs would eventually afford a comprehensive specificity and interaction map to aid epigenetic studies. Show less
Chronic kidney disease (CKD) is a significant public health problem, and recent genetic studies have identified common CKD susceptibility variants. The CKDGen consortium performed a meta-analysis of g Show more
Chronic kidney disease (CKD) is a significant public health problem, and recent genetic studies have identified common CKD susceptibility variants. The CKDGen consortium performed a meta-analysis of genome-wide association data in 67,093 individuals of European ancestry from 20 predominantly population-based studies in order to identify new susceptibility loci for reduced renal function as estimated by serum creatinine (eGFRcrea), serum cystatin c (eGFRcys) and CKD (eGFRcrea < 60 ml/min/1.73 m(2); n = 5,807 individuals with CKD (cases)). Follow-up of the 23 new genome-wide-significant loci (P < 5 x 10(-8)) in 22,982 replication samples identified 13 new loci affecting renal function and CKD (in or near LASS2, GCKR, ALMS1, TFDP2, DAB2, SLC34A1, VEGFA, PRKAG2, PIP5K1B, ATXN2, DACH1, UBE2Q2 and SLC7A9) and 7 loci suspected to affect creatinine production and secretion (CPS1, SLC22A2, TMEM60, WDR37, SLC6A13, WDR72 and BCAS3). These results further our understanding of the biologic mechanisms of kidney function by identifying loci that potentially influence nephrogenesis, podocyte function, angiogenesis, solute transport and metabolic functions of the kidney. Show less
Plasma homocysteine (Hcy) level is associated with cardiovascular disease and may play an etiologic role in vascular damage, a precursor for atherosclerosis. We performed a genome-wide association stu Show more
Plasma homocysteine (Hcy) level is associated with cardiovascular disease and may play an etiologic role in vascular damage, a precursor for atherosclerosis. We performed a genome-wide association study for Hcy in 1786 unrelated Filipino women from the Cebu Longitudinal Health and Nutrition Survey (CLHNS). The most strongly associated single-nucleotide polymorphism (SNP) (rs7422339, P = 4.7 x 10(-13)) encodes Thr1405Asn in the gene CPS1 and explained 3.0% of variation in the Hcy level. The widely studied MTHFR C677T SNP (rs1801133) was also highly significant (P = 8.7 x 10(-10)) and explained 1.6% of the trait variation. We also genotyped these two SNPs in 1679 CLHNS young adult offspring. The MTHFR C677T SNP was strongly associated with Hcy (P = 1.9 x 10(-26)) and explained approximately 5.1% of the variation in the offspring. In contrast, the CPS1 variant was significant only in females (P = 0.11 in all; P = 0.0087 in females). Combined analysis of all samples confirmed that the MTHFR variant was more strongly associated with Hcy in the offspring (interaction P = 1.2 x 10(-5)). Furthermore, although there was evidence for a positive synergistic effect between the CPS1 and MTHFR SNPs in the offspring (interaction P = 0.0046), there was no significant evidence for an interaction in the mothers (P = 0.55). These data confirm a recent finding that CPS1 is a locus influencing Hcy levels in women and suggest that genetic effects on Hcy may differ across developmental stages. Show less
Fibroblast growth factors (FGFs) are secreted molecules that activate the RAS/mitogen-activated protein kinase (MAPK) signaling pathway. In zebrafish development, FGF signaling is responsible for esta Show more
Fibroblast growth factors (FGFs) are secreted molecules that activate the RAS/mitogen-activated protein kinase (MAPK) signaling pathway. In zebrafish development, FGF signaling is responsible for establishing dorsal polarity, maintaining the isthmic organizer, and cardiac ventricle formation. Because several ETS factors are known transcriptional mediators of MAPK signaling, we hypothesized that these factors function to mediate FGF signaling processes. In zebrafish, the simultaneous knock-down of three Pea3 ETS proteins, Etv5, Erm, and Pea3, produced phenotypes reminiscent of embryos deficient in FGF signaling. Morphant embryos displayed both cardiac and left/right patterning defects as well as disruption of the isthmic organizer. Furthermore, the expression of FGF target genes was abolished in Pea3 ETS depleted embryos. To understand how FGF signaling and ETS factors control gene expression, transcriptional regulation of dusp6 was studied in mouse and zebrafish. Conserved Pea3 ETS binding sites were identified within the Dusp6 promoter, and reporter assays showed that one of these sites is required for dusp6 induction by FGFs. We further demonstrated the interaction of Pea3 ETS factors with the Dusp6 promoter both in vitro and in vivo. These results revealed the requirement of ETS factors in transducing FGF signals in developmental processes. Show less
The functions of distinct isoforms of solute carrier family 27 transporters (SLC27A1-6), acetyl-CoA carboxylase (ACACA, ACACB), stearoyl-CoA desaturase (SCD1-4), fatty acid desaturase (FADS1-3), LPIN Show more
The functions of distinct isoforms of solute carrier family 27 transporters (SLC27A1-6), acetyl-CoA carboxylase (ACACA, ACACB), stearoyl-CoA desaturase (SCD1-4), fatty acid desaturase (FADS1-3), LPIN (LPIN1-3), insulin-induced gene (INSIG1, 2), and peroxisome proliferator-activated receptor gamma coactivator1 (PPARGC1A, B) were studied in the mouse mammary gland from pregnancy to lactation. The relative mRNA abundance and percent change in real-time PCR were determined. mRNA expression of SLC27A3 and SLC27A4 was 37- and 1.4-fold more upregulated at 12 days of lactation, respectively (P < 0.01). Transcripts of SCD isoforms were the most abundant, accounting for 59% of all genes measured, and PPARGC1 isoforms were the least (0.06% of all genes measured). The mRNA abundance from ACC, FADS and LPIN accounted for 29, 9 and 2.6%, respectively. INSIG1 mRNA expression was 32-fold more upregulated (P < 0.05), while PPARGC1B was 0.18-fold downregulated at 18 days of lactation (P < 0.01). We concluded that mRNA abundance and expression of these isoforms are affected by the stage of lactation. Show less
Benjamin M Neale, Jesen Fagerness, Robyn Reynolds+23 more · 2010 · Proceedings of the National Academy of Sciences of the United States of America · National Academy of Sciences · added 2026-04-24
Advanced age-related macular degeneration (AMD) is the leading cause of late onset blindness. We present results of a genome-wide association study of 979 advanced AMD cases and 1,709 controls using t Show more
Advanced age-related macular degeneration (AMD) is the leading cause of late onset blindness. We present results of a genome-wide association study of 979 advanced AMD cases and 1,709 controls using the Affymetrix 6.0 platform with replication in seven additional cohorts (totaling 5,789 unrelated cases and 4,234 unrelated controls). We also present a comprehensive analysis of copy-number variations and polymorphisms for AMD. Our discovery data implicated the association between AMD and a variant in the hepatic lipase gene (LIPC) in the high-density lipoprotein cholesterol (HDL) pathway (discovery P = 4.53e-05 for rs493258). Our LIPC association was strongest for a functional promoter variant, rs10468017, (P = 1.34e-08), that influences LIPC expression and serum HDL levels with a protective effect of the minor T allele (HDL increasing) for advanced wet and dry AMD. The association we found with LIPC was corroborated by the Michigan/Penn/Mayo genome-wide association study; the locus near the tissue inhibitor of metalloproteinase 3 was corroborated by our replication cohort for rs9621532 with P = 3.71e-09. We observed weaker associations with other HDL loci (ABCA1, P = 9.73e-04; cholesterylester transfer protein, P = 1.41e-03; FADS1-3, P = 2.69e-02). Based on a lack of consistent association between HDL increasing alleles and AMD risk, the LIPC association may not be the result of an effect on HDL levels, but it could represent a pleiotropic effect of the same functional component. Results implicate different biologic pathways than previously reported and provide new avenues for prevention and treatment of AMD. Show less
Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, Show more
Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes. Show less
Non-steroidal compounds that inhibit 17beta-hydroxysteroid dehydrogenase isoform 3 (17beta-HSD3), an enzyme catalyzing the final step in testosterone biosynthesis in Leydig cells, are under developmen Show more
Non-steroidal compounds that inhibit 17beta-hydroxysteroid dehydrogenase isoform 3 (17beta-HSD3), an enzyme catalyzing the final step in testosterone biosynthesis in Leydig cells, are under development for male contraceptive or treatment of androgen dependent diseases including prostate cancer. A series of curcumin analogues with more stable chemical structures were compared to curcumin as inhibitors of 17beta-HSD3 in rat intact Leydig cells as well as rat and human testis microsomes. Show less
Perfluorooctane acid (PFOA) is classified as a persistent organic pollutant and as an endocrine disruptor. The mechanism by which PFOA causes reduced testosterone production in males is not known. We Show more
Perfluorooctane acid (PFOA) is classified as a persistent organic pollutant and as an endocrine disruptor. The mechanism by which PFOA causes reduced testosterone production in males is not known. We tested our hypothesis that PFOA interferes with Leydig cell steroidogenic enzymes by measuring its effect on 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and 17beta-hydroxysteroid dehydrogenase 3 (17beta-HSD3) activities in rat testis microsomes and Leydig cells. The IC(50)s of PFOA and mode of inhibition were assayed. PFOA inhibited microsomal 3beta-HSD with an IC(50) of 53.2+/-25.9 microM and 17beta-HSD3 with an IC(50) 17.7+/-6.8 microM. PFOA inhibited intact Leydig cell 3beta-HSD with an IC(50) of 146.1+/-0.9 microM and 17beta-HSD3 with an IC(50) of 194.8+/-1.0 microM. The inhibitions of 3beta-HSD and 17beta-HSD3 by PFOA were competitive for the substrates. In conclusion, PFOA inhibits 3beta-HSD and 17beta-HSD3 in rat Leydig cells. Show less
Histone lysine acetylation and methylation have an important role during gene transcription in a chromatin context. Knowledge concerning the types of protein modules that can interact with acetyl-lysi Show more
Histone lysine acetylation and methylation have an important role during gene transcription in a chromatin context. Knowledge concerning the types of protein modules that can interact with acetyl-lysine has so far been limited to bromodomains. Recently, a tandem plant homeodomain (PHD) finger (PHD1-PHD2, or PHD12) of human DPF3b, which functions in association with the BAF chromatin remodelling complex to initiate gene transcription during heart and muscle development, was reported to bind histones H3 and H4 in an acetylation-sensitive manner, making it the first alternative to bromodomains for acetyl-lysine binding. Here we report the structural mechanism of acetylated histone binding by the double PHD fingers of DPF3b. Our three-dimensional solution structures and biochemical analysis of DPF3b highlight the molecular basis of the integrated tandem PHD finger, which acts as one functional unit in the sequence-specific recognition of lysine-14-acetylated histone H3 (H3K14ac). Whereas the interaction with H3 is promoted by acetylation at lysine 14, it is inhibited by methylation at lysine 4, and these opposing influences are important during transcriptional activation of the mouse DPF3b target genes Pitx2 and Jmjd1c. Binding of this tandem protein module to chromatin can thus be regulated by different histone modifications during the initiation of gene transcription. Show less
The antagonism of LINGO-1, a CNS-specific negative regulator of neuronal survival, was shown to promote short-term survival of retinal ganglion cell (RGC) in an ocular hypertension model. LINGO-1 anta Show more
The antagonism of LINGO-1, a CNS-specific negative regulator of neuronal survival, was shown to promote short-term survival of retinal ganglion cell (RGC) in an ocular hypertension model. LINGO-1 antagonists, combined with brain-derived neurotrophic factor (BDNF), can increase the length of neuron survival through an unclear molecular mechanism. To determine the relationship between LINGO-1 and BDNF/TrkB receptor in neuronal protection, we show here that LINGO-1 forms a receptor complex with TrkB and negatively regulates its activation in the retina after ocular hypertension injury. LINGO-1 antagonist antibody 1A7 or soluble LINGO-1 (LINGO-1-Fc) treatment upregulates phospho-TrkB phosphorylation and leads to RGC survival after high intraocular pressure injury. This neuronal protective effect was blocked by anti-BDNF antibody. LINGO-1 antagonism therefore promotes RGC survival by regulating the BDNF and TrkB signaling pathway after ocular hypertension. Show less
The immunotoxicity of tributyltin (TBT) on marine gastropods has been comparatively little studied although risks to wildlife associated with this compound are well known. In this study, a 30-day tria Show more
The immunotoxicity of tributyltin (TBT) on marine gastropods has been comparatively little studied although risks to wildlife associated with this compound are well known. In this study, a 30-day trial was conducted to evaluate the immunotoxic effects on abalone (Haliotis diversicolor supertexta) by exposing a range of doses of TBT (0, 2, 10, and 50 ng/L). Innate immune parameters, including phagocytic ability (PA), lysozyme activity, phenoloxidase (PO) level and superoxide dismutase (SOD) activity were monitored at intervals of 5, 15 and 30 days. Haemolymph protein expression profile was also examined at the end of the experiment. The results showed that PA value, lysozyme activity and PO level significantly decreased compared with the controls (P < 0.05), which indicated that TBT exposure markedly suppressed non-specific immune competence. Exposure to TBT also caused variation in protein expression patterns of haemolymph. Among the protein spots of differential expressions, seven proteins from the haemolymph of TBT-treated abalone were successfully identified by MALDI-TOF-MS analysis. Three protein spots increased and were identified as carrier-like peptide, peroxidase 21 precursor and creatine phosphokinase. These proteins are believed to up-regulate in expression as a response to detoxification and antioxidative stress mechanisms. The other four protein spots that down-regulated in TBT-treated groups were identified as aromatase-like protein, protein kinase C, ceruloplasmin and microtubule-actin crosslinking factor 1, and these proteins play an important role in endocrine regulation and immune defense. Taken together, the results demonstrate that TBT impair abalone immunological ability and is a potential immune disruptor. Show less
MicroRNAs are small non-coding RNA molecules that play essential roles in biological processes ranging from cell cycle to cell migration and invasion. Accumulating evidence suggests that miR-34a, as a Show more
MicroRNAs are small non-coding RNA molecules that play essential roles in biological processes ranging from cell cycle to cell migration and invasion. Accumulating evidence suggests that miR-34a, as a key mediator of p53 tumor suppression, is aberrantly expressed in human cancers. In the present study, we aimed to explore the precise biological role of miR-34a and the global protein changes in HCC cell line HepG2 cells transiently transfected with miR-34a. Transfection of miR-34a into HepG2 cells caused suppression of cell proliferation, inhibition of cell migration and invasion. It also induced an accumulation of HepG2 cells in G1 phase. Among 116 protein spots with differential expression separated by 2-DE method, 34 proteins were successfully identified by MALDI-TOF/TOF analysis. Of these, 15 downregulated proteins may be downstream targets of miR-34a. Bioinformatics analysis produced a protein-protein interaction network, which revealed that the p53 signaling pathway and cell cycle pathway were two major hubs containing most of the proteins regulated by miR-34a. Cytoskeletal proteins such as LMNA, GFAP, MACF1, ALDH2, and LOC100129335 are potential targets of miR-34a. In conclusion, abrogation of miR-34a function could cause downstream molecules to switch on or off, leading to HCC development. Show less