👤 Jianjian Sun

C-reactive protein (CRP) is a heritable marker of chronic inflammation that is strongly associated with cardiovascular disease. We sought to identify genetic variants that are associated with CRP levels. We performed a genome-wide association analysis of CRP in 66 185 participants from 15 population-based studies. We sought replication for the genome-wide significant and suggestive loci in a replication panel comprising 16 540 individuals from 10 independent studies. We found 18 genome-wide significant loci, and we provided evidence of replication for 8 of them. Our results confirm 7 previously known loci and introduce 11 novel loci that are implicated in pathways related to the metabolic syndrome (APOC1, HNF1A, LEPR, GCKR, HNF4A, and PTPN2) or the immune system (CRP, IL6R, NLRP3, IL1F10, and IRF1) or that reside in regions previously not known to play a role in chronic inflammation (PPP1R3B, SALL1, PABPC4, ASCL1, RORA, and BCL7B). We found a significant interaction of body mass index with LEPR (P<2.9×10(-6)). A weighted genetic risk score that was developed to summarize the effect of risk alleles was strongly associated with CRP levels and explained ≈5% of the trait variance; however, there was no evidence for these genetic variants explaining the association of CRP with coronary heart disease. We identified 18 loci that were associated with CRP levels. Our study highlights immune response and metabolic regulatory pathways involved in the regulation of chronic inflammation. Show less

Two markers rs9652490 and rs11856808 both located in intron 3 of the LINGO1 gene have been nominated recently to be associated with essential tremor (ET). Although ET and Parkinson's disease (PD) are considered as different entities, they have many overlapping clinical and pathological features. We aimed to evaluate the role of rs9652490 and rs11856808 in the development of ET and PD. To this point, we sequenced the region involving the two markers in 109 ET cases, 425 sporadic Parkinson's disease (SPD) cases and 430 controls in Chinese population. After stratification by age, the rs9652490G allele suggested protective role in the early onset PD (EOPD, age at onset < or =50 years) group compared with age matched controls (OR=0.56, 95% CI: 0.35-0.90, p=0.015). No other significant association was found. We concluded that the two markers rs9652490 and rs11856808 were not strongly related to the development of ET or late onset SPD, but the rs9652490G allele might be a protective factor for EOPD in Chinese population. Show less

Carbohydrate responsive element-binding protein (ChREBP) is a transcription factor whose expression and activity are increased in pancreatic β-cells maintained at elevated glucose concentrations. We show here that ChREBP inactivation in clonal pancreatic MIN6 β-cells results in an increase in Pdx-1 expression at low glucose and to a small, but significant, increase in Ins2, GcK and MafA gene expression at high glucose concentrations. Conversely, adenovirus-mediated over-expression of ChREBP in mouse pancreatic islets results in decreases in Pdx-1, MafA, Ins1, Ins2 and GcK mRNA levels. These data suggest that strategies to reduce ChREBP activity might protect against β-cell dysfunction in type 2 diabetes. Show less

Carbohydrate-responsive element-binding protein (ChREBP) is a transcription factor that has been shown to regulate carbohydrate metabolism in the liver and pancreatic beta-cells in response to elevated glucose concentrations. Because few genes have been identified so far as bona fide ChREBP-target genes, we have performed a genome-wide analysis of the ChREBP transcriptome in pancreatic beta-cells. Chromatin immunoprecipitation and high-density oligonucleotide tiling arrays (ChIP-chip; Agilent Technologies) using MIN6 pancreatic beta-cell extracts were performed together with transcriptional and other analysis using standard techniques. One of the genes identified by ChIP-chip and linked to glucose sensing and insulin secretion was aryl hydrocarbon receptor nuclear translocator (ARNT)/hypoxia-inducible factor-1beta (HIF-1beta), a transcription factor implicated in altered gene expression and pancreatic-islet dysfunction in type 2 diabetes. We first confirmed that elevated glucose concentrations decreased ARNT/HIF-1beta levels in INS-1 (832/13) cells and primary mouse islets. Demonstrating a role for ChREBP in ARNT gene regulation, ChREBP silencing increased ARNT mRNA levels in INS-1 (832/13) cells, and ChREBP overexpression decreased ARNT mRNA in INS-1 (832/13) cells and primary mouse islets. We demonstrated that ChREBP and Max-like protein X (MLX) bind on the ARNT/HIF-1beta promoter on the proximal region that also confers the negative glucose responsiveness. These results demonstrate that ChREBP acts as a novel repressor of the ARNT/HIF-1beta gene and might contribute to beta-cell dysfunction induced by glucotoxicity. Show less

Autophagy is an intracellular degradation pathway that functions in protein and organelle turnover in response to starvation and cellular stress. Autophagy is initiated by the formation of a complex containing Beclin 1 (BECN1) and its binding partner Phosphoinositide-3-kinase, class 3 (PIK3C3). Recently, BECN1 deficiency was shown to enhance the pathology of a mouse model of Alzheimer Disease (AD). However, the mechanism by which BECN1 or autophagy mediate these effects are unknown. Here, we report that the levels of Amyloid precursor protein (APP) and its metabolites can be reduced through autophagy activation, indicating that they are a substrate for autophagy. Furthermore, we find that knockdown of Becn1 in cell culture increases the levels of APP and its metabolites. Accumulation of APP and APP C-terminal fragments (APP-CTF) are accompanied by impaired autophagosomal clearance. Pharmacological inhibition of autophagosomal-lysosomal degradation causes a comparable accumulation of APP and APP-metabolites in autophagosomes. Becn1 reduction in cell culture leads to lower levels of its binding partner Pik3c3 and increased presence of Microtubule-associated protein 1, light chain 3 (LC3). Overexpression of Becn1, on the other hand, reduces cellular APP levels. In line with these observations, we detected less BECN1 and PIK3C3 but more LC3 protein in brains of AD patients. We conclude that BECN1 regulates APP processing and turnover. BECN1 is involved in autophagy initiation and autophagosome clearance. Accordingly, BECN1 deficiency disrupts cellular autophagy and autophagosomal-lysosomal degradation and alters APP metabolism. Together, our findings suggest that autophagy and the BECN1-PIK3C3 complex regulate APP processing and play an important role in AD pathology. Show less

Lung cancer is one of the most devastating diseases worldwide. RGS17 is previously shown to be over-expressed in human lung adenocarcinomas and plays an important role in lung tumor growth. Here we have identified a miRNA, has-mir-182, involved in the regulation of RGS17 expression through two conserved sites located in its 3' UTR region. Consistently, endogenous RGS17 expression level is regulated by hsa-mir-182 in human lung cancer cell lines. Similar to the knockdown of RGS17, ectopic expression of hsa-mir-182 significantly inhibits lung cancer cell proliferation and anchorage-independent cell growth, which can be rescued by re-expression of RGS17. Taken together, these data have provided the first evidence of miRNA regulation of RGS17 expression in lung cancer. Show less

Glucagon-like peptide-1 receptor (GLP-1R), glucose-dependent insulinotropic polypeptide receptor (GIPR), and G protein-coupled receptor 40 (GPR40) are members of G protein-coupled receptors (GPCR) family. They are abundantly expressed in islet beta cells, and mediate effects of incretins and fatty acids in beta cells. Glucose and 5-AMP-activated protein kinase (AMPK) are known to be involved in the regulation of beta cell function. Metformin and the potential therapeutic drug for type 2 diabetes, 5-amino-4-imidazolecarboxamide riboside (AICAR), are both known activators of AMPK. Here we studied the effects of glucose, metformin, and AICAR on the expression of GPCR in INS-1 beta cell. INS-1 beta cells were supplemented with different concentrations of glucose, metformin, or AICAR. The expressions of GLP-1R, GIPR, GPR40, and a nuclear transcription factor - peroxisome-proliferator activated receptor alpha (PPARalpha) - were analyzed by real-time RT-PCR and immunoblotting. The time-course of the mRNA degradation of these receptors was also monitored by applying actinomycin D to cells. We demonstrated that the expressions of GLP-1R, GIPR, and PPARalpha were downregulated when INS-1beta cells were treated with glucose, while their expressions were upregulated when treated with metformin or AICAR. Glucose, metformin, or AICAR treatment had no obvious effect on the expression of GPR40. These results indicate that glucose, metformin, and AICAR regulated the expressions of incretin receptors and PPARalpha, but not GPR40 in beta cells. Whether AMPK is a key regulator of these factors mediated receptor regulation remains to be investigated further. Show less

We investigated the relationship between hypertriglyceridemia and the single-nucleotide polymorphisms (SNPs) on APOA5 in human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) in Taiwan. Receipt of protease inhibitor-based HAART, high baseline triglyceride levels, and carriage of APOA5 SNP3 or c.553G>T variants or APOA5 SNP1T/SNP2G/SNP3C/c.553T haplotype were statistically significantly associated with development of extreme hypertriglyceridemia (triglyceride level, >500 mg/dL). Show less

DNA double-strand break (DSB) repair involves complex interactions between chromatin and repair proteins, including Tip60, a tumour suppressor. Tip60 is an acetyltransferase that acetylates both histones and ATM (ataxia telangiectasia mutated) kinase. Inactivation of Tip60 leads to defective DNA repair and increased cancer risk. However, how DNA damage activates the acetyltransferase activity of Tip60 is not known. Here, we show that direct interaction between the chromodomain of Tip60 and histone H3 trimethylated on lysine 9 (H3K9me3) at DSBs activates the acetyltransferase activity of Tip60. Depletion of intracellular H3K9me3 blocks activation of the acetyltransferase activity of Tip60, resulting in defective ATM activation and widespread defects in DSB repair. In addition, the ability of Tip60 to access H3K9me3 is dependent on the DNA damage-induced displacement of HP1beta (heterochromatin protein 1beta) from H3K9me3. Finally, we demonstrate that the Mre11-Rad50-Nbs1 (MRN) complex targets Tip60 to H3K9me3, and is required to activate the acetyltransferase activity of Tip60. These results reveal a new function for H3K9me3 in coordinating activation of Tip60-dependent DNA repair pathways, and imply that aberrant patterns of histone methylation may contribute to cancer by altering the efficiency of DSB repair. Show less

To identify the disease-causing gene mutations and to reveal the relationship between the genotype and the phenotype in Chinese patients with hypertrophic cardiomyopathy (HCM). One hundred unrelated patients with HCM and 120 controls were enrolled in this study. The full encoding exons and flanking sequences of the cardiac myosin binding protein C gene (MYBPC3) were amplified with PCR and the products were sequenced. A novel missense mutation c.706T > C was identified in exon 6 of MYBPC3 gene in three HCM patients, which resulted a Serine (S) to Glycine (G) exchange at amino acid residue 236 (S236G). The clinical phenotypes of the three patients were different (2 obstructive HCM, 1 non-obstructive HCM). The 120 controls were normal in the genetic test. The novel S236G mutation in MYBPC3 gene was a hot-spot mutation in Chinese patients with HCM. Show less

To screen the MYBPC3 gene mutations in Han Chinese patients with hypertrophic cardiomyopathy (HCM). Sixty-six patients with HCM were enrolled for the study. The exons in the functional regions of MYBPC3 were amplified with PCR and the products were sequenced. Four novel mutations and four common polymorphisms were identified in this patient cohort. A Lys301fs mutation in exon10 was evidenced in a H30, and when he was 47 years old, he had the chest tightness, shortness of breath with septal hypertrophy of 18.7mm; a Asp463stop mutation in exon17 was detected in a H48, he was 24 years old 24-year-old when a medical examination showed ventricular septal hypertrophy of 15.4 mm; both Gly523Arg mutation in exon18 and Tyr847His mutation in exon26 were found in a H53 with onset age 36 years old, feeling chest tightness after excise and his ventricular septal hypertrophy was 27 mm that time. MYBPC3 mutations occurred in 4.5% patients in this cohort. These mutations were not found in 100 non-HCM control patients. MYBPC3 mutation is presented in a small portion of Han Chinese patients with HCM. Show less

To investigate the genotype-phenotype correlation in Chinese familial hypertrophic cardiomyopathy (HCM), peripheral blood samples were collected from 7 members of a Chinese HCM family, and 120 normal subjects were recruited as control. The full encoding exons and flanking sequences of the cardiac troponin T (TNNT2) gene, beta-myosin heavy chain (MYH7) gene and myosin binding protein C (MYBPC3) gene were amplified and the products were sequenced directly to detect the mutations. A missense mutation, c.1273G>A, was identified in exon 14 of the MYH7 gene in 4 members of the Chinese HCM family, which resulted a glycine (Gly) to arginine (Arg) exchange at amino acid residue 425. The 425th glycine amino acid residue is highly conservative across the different species. The clinical phenotypes among the family members who carried this mutation presented significant individual differences. The c.1273G>A mutation of the MYH7 gene might be the causal mutation of the familial HCM. The heterogeneity of phenotypes suggested that multiple factors may be involved in the pathogenesis of HCM. Show less

In order to examine the role of astacene on mice body development and the expression of energy metabolism related genes in mice, we treated mice (Kunming white) and primary culture of mouse muscle cells with astacene of higher and lower concentration. Then the total mRNA was extracted from the muscle tissue and cells respectively, and the mRNA levels of UCP3 and LXRalpha were detected by RT-PCR in all the samples. Compared with the control group, the body weight of mice in high concentrations of astacene group grown slowly, and the expressions of UCP3 genes decreased significantly in muscle tissue of the 10th day and the 30th day as well as the cells of treated for 24 h (P<0.05). The expression of LXRalpha gene increased significantly in all samples (P<0.05) and reached its peak at 72 h (P<0.01). With the treatment of lower concentration of astacene, the expressions of UCP3 and LXRalpha gene mRNA in muscle tissue did not alter much, but in muscle cells treated for 24 h, the mRNA level of UCP3 gene decreased significantly (P<0.05), and LXRalpha gene increased significantly (P<0.05). The results suggest that astacene has a role in regulating the energy use in mice muscle. Show less

To explore the possible mechanism of the inhibitory effect of liver X receptor alpha (LXRalpha) on lipopolysaccharide (LPS)-induced inflammation in mouse Kupffer cells (KCs). The KCs isolated from the liver of male KM mice and cultured in RPMI 1640 containing 20% FBS for 24 h were divided into control, LPS, T0901317, and LPS+T0901317 groups with corresponding treatments. The expressions of LXRalpha, interferon regulatory factor 3 (IRF3) and glucocorticoid receptor interacting protein 1 (GRIP1) in the KCs were detected by Western blotting. The levels of interferon beta (IFNbeta), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in the supernatant were detected by enzyme-linked immunosorbent assay (ELISA). The level of LXRalpha protein was highest in T0901317 group and lowest in LPS group, and was significantly higher in LPS+T0901317 group than in LPS group but lower than in T0901317 group (P<0.05). The levels of IRF3 and GRIP1 protein were the highest in LPS group, and significantly lowered by T0901317 treatment (P<0.05). The expression of IRF3 and GRIP1 proteins in LPS group and LPS+ T0901317 group were significantly higher than those in the control and T0901317 groups (P<0.05). The concentration of IFN-beta was significantly higher in LPS group than in the control and T0901317 group (P<0.05), and decreased in LPS+T0901317 group in comparison with that in LPS group (P<0.05). IFN-beta was the lowest in T0901317 group. The levels of TNF-alpha and IL-1beta were the highest in LPS group (P<0.05), and comparable between the other 3 groups (P>0.05). Pre-treatment with T0901317 before LPS stimulation can suppress the expressions of IRF3 and GRIP1 to inhibit the inflammation and hence Kupffer cell activation. Show less

Liver X receptors (LXRs) are important transcriptional regulators of lipid homeostasis and proliferation in several cell types. However, the roles of LXRs in pancreatic beta cells have not been fully established. The aim of this study was to investigate the effects of LXRs on pancreatic beta cell proliferation. Gene expression was analysed using real-time RT-PCR. Transient transfection and reporter gene assays were used to determine the transcriptional activity of LXRs in pancreatic beta cells. Cell viability and proliferation were analysed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), DNA fluorometric, BrdU labelling and [(3)H]thymidine incorporation assays. Cell cycle distribution was investigated by flow cytometry analysis. Adenovirus-based RNA interference was used to knockdown LXRalpha, LXRbeta and p27 in MIN6 cells and mouse islets. We found that both Lxralpha (also known as Nr1h3) and Lxrbeta (also known as Nr1h2) were expressed and transactivated the LXR response element in HIT-T15 and MIN6 cells. Activation of LXRs dose-dependently inhibited pancreatic beta cell viability and proliferation. This was accompanied by beta cell cycle arrest at the G1 phase. Furthermore, LXR activation increased levels of the p27 protein by inhibiting its degradation. Knockdown of p27 reversed these effects of LXR activation on growth inhibition and cell cycle arrest. Our observations indicate that LXR activation inhibits pancreatic beta cell proliferation through cell cycle arrest. A well-known regulator of pancreatic beta cell cycle progression, p27, is upregulated and mediates the effects of LXRs on growth inhibition in beta cells. These observations suggest the involvement of aberrant activation of LXR in beta cell mass inadequacy, which is an important step in the development of type 2 diabetes. 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

A novel mutation, repro5, was isolated in a forward genetic screen for infertility mutations induced by ENU mutagenesis. Homozygous mutant mice were phenotypically normal but were infertile. Oocytes from mutant females appeared normal, but were severely maturation-defective in that they had reduced ability to progress to metaphase II (MII), and those reaching MII were unable to progress beyond the two pronuclei stage following in vitro fertilization (IVF). Mutant males exhibited defective spermiogenesis, resulting in oligoasthenoteratospermia. Genetic mapping, positional cloning, and complementation studies with a disruption allele led to the identification of a mutation in Brwd1 (Bromodomain and WD repeat domain containing 1) as the causative lesion. Bromodomain-containing proteins typically interact with regions of chromatin containing histones hyperacetylated at lysine residues, a characteristic of chromatin in early spermiogenesis before eventual replacement of histones by the protamines. Previous data indicated that Brwd1 is broadly expressed, encoding a putative transcriptional regulator that is believed to act on chromatin through interactions with the Brg1-dependent SWI/SNF chromatin-remodeling pathway. Brwd1 represents one of a small number of genes whose elimination disrupts gametogenesis in both sexes after the major events of meiotic prophase I have been completed. Show less

Imprinted genes are monoallelically expressed from either the maternal or paternal genome. Because cancer develops through genetic and epigenetic alterations, imprinted genes affect tumorigenesis depending on which parental allele undergoes alteration. We have shown previously in a mouse model of neurofibromatosis type 1 (NF1) that inheriting mutant alleles of Nf1 and Trp53 on chromosome 11 from the mother or father dramatically changes the tumor spectrum of mutant progeny, likely due to alteration in an imprinted gene(s) linked to Nf1 and Trp53. In order to identify imprinted genes on chromosome 11 that are responsible for differences in susceptibility, we tested candidate imprinted genes predicted by a bioinformatics approach and an experimental approach. We have tested 30 candidate genes (Havcr2, Camk2b, Ccdc85a, Cntnap1, Ikzf1, 5730522E02Rik, Gria1, Zfp39, Sgcd, Jup, Nxph3, Spnb2, Asb3, Rasd1, Map2k3, Map2k4, Trp53, Serpinf1, Crk, Rasl10b, Itga3, Hoxb5, Cbx1, Pparbp, Igfbp4, Smarce1, Stat3, Atp6v0a1, Nbr1 and Meox1), two known imprinted genes (Grb10 and Impact) and Nf1, which has not been previously identified as an imprinted gene. Although we confirmed the imprinting of Grb10 and Impact, we found no other genes imprinted in the brain. We did, however, find strain-biased expression of Camk2b, 5730522E02Rik, Havcr2, Map2k3, Serpinf1, Rasl10b, Itga3, Asb3, Trp53, Nf1, Smarce1, Stat3, Cbx1, Pparbp and Cntnap1. These results suggest that the prediction of imprinted genes is complicated and must be individually validated. This manuscript includes supplementary data listing primer sequences for Taqman assays and Ct values for Taqman PCR. Show less

To prepare and characterize the monoclonal antibody (mAb) against human carbamyl phosphate synthetase I (CPSI) and make a study of its application. Normal human liver tissues were homogenized, and their mitochondria were isolated by differential centrifugation. The total mitochondrial proteins were used to immunize BALB/c mice to prepare mAb using the routine hybridoma technique. The mAb was detected by ELISA, Western blot immunohistochemistry and immunofluorecent staining. The specificity of mAb was identified by mass spectrometry (MS) and immunoprecipitation (IP) and then confirmed by Uni-ZAP expression library screening. The antibody was used to isolate potential enzymatic complexes by immunocapturing. Three hybridoma cell lines BEH045, ACB271 and BFG021 secreting specific mAb against CPS1 were obtained. The Ig subclass of the mAb was IgG(1), which was used in ELISA, Western blot immunohistochemistry, immunoprecipitation, immunofluorecent staining and the isolation of potential enzymatic complexes. A hybridoma cell line which can secre specific mAb against CPSI stably has been established. The specific mAb against CPSI is of value to the research into the functions and distribution of CPSI. Show less

As a model for both multistep and multipathway carcinogenesis, colorectal neoplastic progression provides paradigms for researching both oncogenes and tumor suppressor genes (TSGs). However, the mechanism of colorectal cancer (CRC) is not completely understood, and many genes may be involved in the colorectal carcinogenesis. The purpose of this study was to screen for the potential TSGs on chromosome 1q31.1-32.1 in Chinese patients with sporadic colorectal cancer, to explore whether colorectal cancer in the Chinese population has unique genetic alterations and determine whether other putative TSGs exist and contribute to colon carcinogenesis. Six polymorphic microsatellite markers, at a density of approximately one marker in every 1.6 cM, were chosen for refined loss of heterozygosity (LOH) mapping of 1q31.1-32.1. Eighty-three colorectal cancer patients' tumor and normal DNA were analyzed via polymerase chain reaction (PCR) for these microsatellite markers. PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.1 and Genotype 2.1 software were used for LOH scanning and analysis. On the basis of refined LOH mapping results, we undertook a microarray-based expression screening to identify tumor association genes in 19 of the CRC cases. The average LOH frequency of 1q31.1-32.1 was 24.41%, with the highest frequency of 36.73% (18/49) at D1S2622, and the lowest of 16.42% (11/67) at D1S412. A minimal region of frequent deletion was located within a 2 cM genomic segment at D1S413-D1S2622. There was no significant association between LOH of any marker in the studied regions and the clinicopathological data (patient sex, age, tumor size, growth pattern, or Dukes stage). On the basis of refined mapping results, we chose 25 genes located in the D1S413-D1S2622 (1q31.3-32.1) region and presented a microarray-based high throughput screening approach in 19 sporadic CRC cases to identify candidate CRC related tumor suppressor genes. This study found 4 significantly down-expressed genes, including CSRP1, LMOD1, PPP1R12B and CFHL3. There was no significant association between expression levels of CFHL3, CSRP1, LMOD1, PPP1R12B and the clinicopathological data. By database searching, CSRP1 was hypothesized to be a colorectal cancer related tumor suppressor gene. Through detailed deletion mapping, we found that the 1q31.3-32.1 region might harbor one or more colorectal cancer related tumor suppressor gene (s). And by microarray-based high-throughput screening of candidate genes located in this region and by subsequent database searching, we present the first evidence that CSRP1 might be involved in the progression of CRC. Show less

To study the disease-causing gene mutations in familial hypertrophic cardiomyopathy (HCM) in Chinese and to reveal the relationship between the genotype and the phenotype. Peripheral blood samples were collected from 12 members of a HCM family, and 120 healthy volunteers in China. PCR and double deoxygenation chain termination method were used to analyze the cardiac troponin T gene (TNNT2), beta-myosin heavy chain gene (MYH7) gene and myosin binding protein C gene (MYBPC3) and to detect mutations. Mutation G14452A was identified in exon 22 of MYH7 gene in 4 family members, causing the conversion of glycine (G) into glutamic acid (E). The onset ages and clinical manifestations of the family members carrying the mutation G823E, including 2 patients (the proband, male, with the onset age of 51, and his 26-year-old second son with the onset age of 20), and 2 carriers (his 31-year-old elder son and 29-year-old elder daughter), presented significant individual differences. The G823E mutation of MYH7 gene is the causal mutation of familial HCM. The heterogeneity of phenotypes suggests that multiple factors may be involved in the pathogenesis of HCM. Show less

To reveal genotype-phenotype correlation of disease-causing gene mutations in Chinese hypertrophic cardiomyopathy (HCM) pedigree. Peripheral venous blood samples were collected from two Chinese HCM families and 120 healthy subjects were recruited as normal control. The full encoding exons and flanking sequences of the cardiac troponin T gene (TNNT2), beta-myosin heavy chain gene (MYH7) and myosin binding protein C gene (MYBPC3) were amplified with the polymerase chain reaction method, DNA sequencing was used to detect the mutation. In ZZJ family, mutation G12101A was identified in exon 21 of MYBPC3 gene in 4 family members [the arginine (R) converted to histidine (H)]. In this pedigree, three out of eight family members were diagnosed as HCM and with a penetrance of 75%. In FHL family, mutation G15391A was identified in exon 23 of MYH7 gene in 3 family members [the glutamic acid (E) converted to lysine (K)]. In this pedigree, three out of six family members were diagnosed as HCM and with a penetrance of 100%. Echocardiography showed obstruction of left ventricular outflow tract in two out of the three HCM patients. Our results showed that the G12101A mutation of MYBPC3 gene is the causal mutation of familial HCM with mild phenotype. The G15391A mutation of MYH7 gene is the causal mutation of familial HCM with malignant phenotype and a penetrance of 100%. Screening mutations in the MYH7 gene should be viewed as a reasonable procedure in obstructive HCM patients. Show less

Apolipoprotein AIV (apo AIV) and cholecystokinin (CCK) are peptides that act both peripherally and centrally to reduce food intake by decreasing meal size. The present study examined the effects of intraperitoneally administered bolus doses of recombinant apo AIV, CCK-8, and a combination of subthreshold doses of apo AIV and CCK on 4-h food intake in rats that were fasted overnight. Apo AIV at 100 microg/kg reduced food intake significantly relative to the saline control for 1 h, as did doses of CCK-8 at or above 0.125 microg/kg. Doses of apo AIV (50 microg/kg) or CCK (0.06 microg/kg) alone had no effect on food intake. However, when these subthreshold doses of apo AIV and CCK were administered together, the combination produced a significant inhibition of food intake relative to saline controls (P < 0.001), and the duration of the effect was longer than that caused by the administration of either apo AIV or CCK alone. The satiation effect produced by CCK-8 + apo AIV was attenuated by lorglumide, a CCK1 receptor antagonist. We conclude that, whereas the intraperitoneal administration of doses of either recombinant apo AIV or CCK at or above threshold levels reduces food intake, the coadministration of subthreshold doses of the two peptides is highly satiating and works via CCK1 receptor. Show less

Glycogen synthase kinase 3 (GSK3) encodes a serine/threonine protein kinase, is known to play roles in many biological processes. Two closely related GSK3 isoforms encoded by distinct genes: GSK3alpha (51 kDa) and GSK3beta (47 kDa). In previously studies, most GSK3 inhibitors are not only inhibiting GSK3, but are also affecting many other kinases. In addition, because of highly similarity in amino acid sequence between GSK3alpha and GSK3beta, making it difficult to identify an inhibitor that can be selective against GSK3alpha or GSK3beta. Thus, it is relatively difficult to address the functions of GSK3 isoforms during embryogenesis. At this study, we attempt to specifically inhibit either GSK3alpha or GSK3beta and uncover the isoform-specific roles that GSK3 plays during cardiogenesis. We blocked gsk3alpha and gsk3beta translations by injection of morpholino antisense oligonucleotides (MO). Both gsk3alpha- and gsk3beta-MO-injected embryos displayed similar morphological defects, with a thin, string-like shaped heart and pericardial edema at 72 hours post-fertilization. However, when detailed analysis of the gsk3alpha- and gsk3beta-MO-induced heart defects, we found that the reduced number of cardiomyocytes in gsk3alpha morphants during the heart-ring stage was due to apoptosis. On the contrary, gsk3beta morphants did not exhibit significant apoptosis in the cardiomyocytes, and the heart developed normally during the heart-ring stage. Later, however, the heart positioning was severely disrupted in gsk3beta morphants. bmp4 expression in gsk3beta morphants was up-regulated and disrupted the asymmetry pattern in the heart. The cardiac valve defects in gsk3beta morphants were similar to those observed in axin1 and apcmcr mutants, suggesting that GSK3beta might play a role in cardiac valve development through the Wnt/beta-catenin pathway. Finally, the phenotypes of gsk3alpha mutant embryos cannot be rescued by gsk3beta mRNA, and vice versa, demonstrating that GSK3alpha and GSK3beta are not functionally redundant. We conclude that (1) GSK3alpha, but not GSK3beta, is necessary in cardiomyocyte survival; (2) the GSK3beta plays important roles in modulating the left-right asymmetry and affecting heart positioning; and (3) GSK3alpha and GSK3beta play distinct roles during zebrafish cardiogenesis. Show less

To investigate the expression of PSD-93 mRNA and NR2B mRNA in the brain tissue from the patients with epilepsy so as to explore the possible mechanisms of the pathogenesis of the epilepsy. Fifty-six patients with epilepsy were divided into intractable epilepsy (IE) and non-intractable epilepsy (NIE) groups. cDNA microarrays prepared from the brain tissues obtained from these two groups were scanned and comparison to those from the non-epileptogenic control (C) was made. Expression level of PSD-93mRNA and NR2BmRNA were examined by reverse transcription polymerase chain reaction (GAPDH gene, internal control). Expression ratio (target gene/GAPDH) was used to evaluate each gene relative expression level. The cDNA microarray analysis showed that the expression of PSD-93 mRNA related to the function of NMDAR-NO signal transduction pathway was significantly higher in epilepsy patients than those in the controlled group. The results of RT-PCR were consistent with those of the cDNA microarrays. The relative expression ratio of PSD-93 in patients with non-epileptogenic control, NIE, and IE was 0.159, 0.368, and 0.341, respectively. Correspondingly, that of NR2B was 0.198, 0.738, and 0.903, respectively. The expressions of PSD-93 and NR2B in the NIE and IE were significantly higher than those of control, respectively (P<0.05). However, there was no significantly difference the expression of PSD-93 between NIE and IE. (P>0.05), neither do that of NR2B (P>0.05). The upregulated expressions of PSD-93 mRNA and NR2BmRNA may be involved in the pathogenesis of epilepsy. Show less

ApoAV, a newly discovered apolipoprotein, plays a key role in human triglyceride homeostasis; however, the structure-function correlation of apoAV is not clearly understood. To explore the relationship, wild type and six deletion mutants, that is (AV (Delta(1-51)), AV (Delta(51-128)), AV (Delta(132-188)), AV (Delta(192-238)), AV (Delta(246-299)), AV (Delta(301-343))), of human apoAV expressed in Escherichia coli were studied. All the deleted regions together encompass almost the entire 343 amino acid sequence of wild type apoAV. Circular dichroism spectroscopy showed that the alpha helical content of lipid-free wild type apoAV was 46%. In comparison with wild type apoAV, AV (Delta(192-238)) and AV (Delta(301-343)) displayed significantly decreased lipid binding activities, confirming the importance of these two regions in lipid binding function of apoAV. While, the LPL activation function of apoAV remarkably impaired after deletion of residues 192-238. These findings suggested that the domain (192-238) is absolutely necessary for apoAV in lipid binding and lipoprotein lipase activation. Show less

Elevation in plasma triglycerides (TG) has been widely accepted as a coronary artery disease (CAD) risk predictor. Recently, a new apolipoprotein playing an important role in TG metabolism named apolipoprotein AV (apoAV) was discovered, which is encoded by the APOA5 gene. Several single nucleotide polymorphisms (SNPs) of APOA5 associated with increased TG concentrations have been identified. We here report that a recently identified genetic variant, c.553G>T in the APOA5 gene which causes a substitution of a cysteine for a glycine residue at amino acid residue 185(G185C) is also associated with increased TG levels. To investigate the association between this genetic variation and the risk of CAD, a case-control study comprising 232 patients with CAD and 302 controls from the same area of China was performed. The minor allele frequencies of c.553G > T for the CAD and control groups were 7.76 and 3.97%, respectively (P = 0.008). In both the CAD and control groups, the T allele carriers had higher serum TG levels than homozygous carriers of the major G allele (CAD group: 2.67 +/- 1.48 mmol/l versus 1.95 +/- 1.02 mmol/l, P = 0.021; controls: 2.31 +/- 1.20 mmol/l versus 1.68 +/- 0.95 mmol/l, P = 0.002). After adjustment for age, gender, body mass index, smoking status, glucose and presence of hypertension, the odds ratio (OR) for CAD in the T allele carriers was 2.089 (95% CI = 1.140-3.830, P = 0.017), in comparison to the individuals without the T allele. These results suggest that the APOA5 c.553G > T polymorphism is an important predictor for hypertriglyceridemia and CAD. Show less

Human protein kinases make up a large superfamily of homologous proteins, which are related by virtue of their kinase domains (also known as catalytic domains). Here we report the cloning and characterization of a novel human MAST4 (microtubule associated serine/threonine kinase family member 4) gene, which locates on human chromosome 5q13. The MAST4 cDNA is 7587 base pairs in length and encodes a putative protein of 2435 amino acids which contains a serine/threonine kinase domain and a PDZ domain. MAST4 protein has 64%, 63%, 59% and 39% identical aminoacid residues with MAST1, MAST2, MAST3 and MASTL respectively. RT-PCR analysis revealed relatively high expression level of MAST4 in most normal human tissues, with an exception of in testis, small intestine, colon and peripheral blood leukocyte. Show less

The aim of this study was to screen the disease-causing gene mutations and investigate the genotype-phenotype correlation in 10 Chinese pedigrees with familial hypertrophic cardiomyopathy (HCM). There are 91 family members from these 10 pedigrees and 5 members were normal mutated carriers, 23 members were HCM patients (14 male) aged from 1.5 to 73 years old. The functional regions of myosin heavy chain gene (MYH7), cardiac myosin-binding protein C (MYBPC3) and cardiac troponin T gene (TNNT2) were screened with PCR and direct sequencing technique. Clinical information from all patients was also evaluated in regard to the genotype. Mutations were found in 5 out of 10 pedigrees. Mutations in MYH7 (Arg663His, Glu924Lys and Ile736Thr) were found in 3 pedigrees and 3 patients from these pedigrees suffered sudden death at age 20-48 years old during sport. Mutations in MYBPC3 were found in 2 pedigrees, 1 with complex mutation (Arg502Trp and splicing mutation IVS27 + 12C > T) and 1 with novel frame shift mutation (Gly347fs) and the latter pedigree has sudden death history. No mutation was identified in TNNT2. Although the Han Chinese is a relatively homogeneous ethnic group, different HCM gene mutations were responsible for familiar HCM suggesting the heterogeneity nature of the disease-causing genes and HCM MYH7 mutations are associated with a higher risk of sudden death in this cohort. Furthermore, identical mutation might result in different phenotypes suggesting that multiple factors might be involved in the pathogenesis of familiar HCM. Show less

To investigate the relationship between apolipoprotein A5(apoA5) - 1131T > C polymorphism and the susceptibility of coronary artery disease (CAD) in Chinese. The restriction fragment length polymorphism of apoA5 gene - 1131T > C was studied using PCR in a case-control study which enrolled 235 patients with CAD diagnosed by angiography and 262 healthy controls from Jiangsu province. The frequencies of T, C allele were 59.57%ì40.43% and 65.65%, 34.35% in CAD group and control group respectively. There was statistically significant difference in allele frequencies between CAD group and control group (P < 0.05). The susceptibility to CAD for the CC genotype was much higher than that for wild type TT (OR = 1.872, 95% CI = 1.039 - 3.376, P = 0.037), even after the use of Logistic regression models (OR = 2.285, 95% CI = 1.222 - 4.274, P = 0.012). In control group, there was significant difference in TG levels among different genotypes, the C allele carriers had higher serum TG concentration (P = 0.007). apoA5 - 1131T > C polymorphism is associated with an increased risk of CAD and is also in strong association with serum TG levels. Show less