Search tips
Search criteria

Results 1-25 (65)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
1.  Urinary prostasin excretion is associated with adiposity in non-hypertensive African American adolescents 
Pediatric research  2013;74(2):206-210.
Metabolic abnormalities in obesity can overstimulate the renal epithelial sodium channel (ENaC) and subsequently lead to blood pressure (BP) elevation. Prostasin, a membrane-bound/secretive serine protease, is thought to activate ENaC via the proteolytic cleavage of the channel. Our specific aim was to explore whether there is a relationship between adiposity and urinary prostasin excretion at the population level.
In 271 African-American adolescents, urinary prostasin concentrations were determined by enzyme-linked immunosorbent assay and normalized by urinary creatinine.
Urinary prostasin excretion increased in the over- weight/obese group (n = 110, 38.2 ± 4.0 ng/mg) vs. the normal-weight group (n = 161, 20.7 ± 1.2 ng/mg, P = 0.03). Urinary prostasin excretion was significantly correlated with BMI percentiles (r = 0.14, P = 0.02), waist circumference (r = 0.13, P = 0.05), total body fat mass (r = 0.20, P < 0.01), and percentage body fat (r = 0.23, P < 0.01). Urinary prostasin excretion was also correlated with plasma aldosterone (r = 0.11, P = 0.05) and systolic BP (SBP; r = 0.15, P = 0.02), but the significances disappeared after adjustment of any of the adiposity variables.
Our data for the first time suggest that adiposity plays a role in urinary prostasin excretion, and its associations with aldosterone and BP appear to be modulated by adiposity. Whether urinary prostasin excretion is a biomarker/mechanism underlying obesity-related hypertension deserves further investigations.
PMCID: PMC4332551  PMID: 23863785
2.  Identifying Genetic Variants for Heart Rate Variability in the Acetylcholine Pathway 
PLoS ONE  2014;9(11):e112476.
Heart rate variability is an important risk factor for cardiovascular disease and all-cause mortality. The acetylcholine pathway plays a key role in explaining heart rate variability in humans. We assessed whether 443 genotyped and imputed common genetic variants in eight key genes (CHAT, SLC18A3, SLC5A7, CHRNB4, CHRNA3, CHRNA, CHRM2 and ACHE) of the acetylcholine pathway were associated with variation in an established measure of heart rate variability reflecting parasympathetic control of the heart rhythm, the root mean square of successive differences (RMSSD) of normal RR intervals. The association was studied in a two stage design in individuals of European descent. First, analyses were performed in a discovery sample of four cohorts (n = 3429, discovery stage). Second, findings were replicated in three independent cohorts (n = 3311, replication stage), and finally the two stages were combined in a meta-analysis (n = 6740). RMSSD data were obtained under resting conditions. After correction for multiple testing, none of the SNPs showed an association with RMSSD. In conclusion, no common genetic variants for heart rate variability were identified in the largest and most comprehensive candidate gene study on the acetylcholine pathway to date. Future gene finding efforts for RMSSD may want to focus on hypothesis free approaches such as the genome-wide association study.
PMCID: PMC4226560  PMID: 25384021
3.  Genome-Wide Association Studies and Beyond 
Hypertension  2010;56(6):1035-1037.
PMCID: PMC4102918  PMID: 21060002
4.  DNA Methylation of the LY86 Gene is Associated With Obesity, Insulin Resistance, and Inflammation 
Previous genome-wide association studies (GWAS) have identified a large number of genetic variants for obesity and its related traits, representing a group of potential key genes in the etiology of obesity. Emerging evidence suggests that epigenetics may play an important role in obesity. It has not been explored whether the GWAS-identified loci contribute to obesity through epigenetics (e.g., DNA (deoxyribonucleic acid) methylation) in addition to genetics.
A multi-stage cross-sectional study was designed. We did a literature search and identified 117 genes discovered by GWAS for obesity and its related traits. Then we analyzed whether the methylation levels of these genes were also associated with obesity in two genome-wide methylation panels. We examined an initial panel of seven adolescent obese cases and seven age-matched lean controls, followed by a second panel of 48 adolescent obese cases and 48 age- and gender-matched lean controls. The validated CpG sites were further replicated in two independent replication panels of youth (46 vs. 46 and 230 cases vs. 413 controls, respectively) and a general population of youth, including 703 healthy subjects.
One CpG site in the lymphocyte antigen 86 (LY86) gene, which showed higher methylation in the obese in both the initial (p = .009) and second genome-wide DNA methylation panel (p = .008), was further validated in both replication panels (meta p = .00016). Moreover, in the general population of youth, the methylation levels of this region were significantly correlated with adiposity indices (p ≤.02), insulin resistance (p = .001), and inflammatory markers (p < .001).
By focusing on recent GWAS findings in genome-wide methylation profiles, we identified a solid association between LY86 gene DNA methylation and obesity.
PMCID: PMC4090018  PMID: 24735745
DNA methylation; obesity; GWAS; insulin resistance; inflammation
5.  A 2-step penalized regression method for family-based next-generation sequencing association studies 
BMC Proceedings  2014;8(Suppl 1):S25.
Large-scale genetic studies are often composed of related participants, and utilizing familial relationships can be cumbersome and computationally challenging. We present an approach to efficiently handle sequencing data from complex pedigrees that incorporates information from rare variants as well as common variants. Our method employs a 2-step procedure that sequentially regresses out correlation from familial relatedness and then uses the resulting phenotypic residuals in a penalized regression framework to test for associations with variants within genetic units. The operating characteristics of this approach are detailed using simulation data based on a large, multigenerational cohort.
PMCID: PMC4143756  PMID: 25519315
6.  A genome-wide methylation study of severe vitamin D deficiency in African American adolescents 
The Journal of pediatrics  2012;162(5):1004-9.e1.
To test the hypothesis that changes in DNA methylation are involved in vitamin D deficiency–related immune cell regulation using an unbiased genome-wide approach combined with a genomic and epigenomic integrative approach.
Study design
We performed a genome-wide methylation scan using the Illumina HumanMethylation 27 BeadChip on leukocytes DNAs of 11 cases of vitamin D deficiency (serum 25(OH)D≤ 25 nmol/L) and 11 age-matched controls (serum 25(OH)D>75 nmol/L); the subjects were African American normal-weight (BMI<85th percentile) males aged 14-19 years. The Limma package was used to analyze each CpG site for differential methylation between cases and controls. To correct for multiple testing, the set of raw p values were converted to false discovery rates (FDR). We also compared our findings with the recent data from GWAS of circulating 25(OH) D levels and then performed a permutation test to examine whether the “double hit” genes were randomly enriched.
A total of 79 CpG sites achieved raw p<0.001. Of the 79 CpG sites, 2 CpG sites survived multiple testing: cg16317961 (raw p=3.5 × 10-6, FDR=0.078, in MAPRE2) and cg04623955 (raw p=5.9 × 10-6, FDR=0.078, in DIO3). Furthermore, 3 out of the 4 genes previously identified in the two GWAS studies were also significant at the methylation level (DHCR7: cg07487535, p=0.015 & cg10763288, p=0.017; CYP2R1: cg25454890, p=0.040; CYP24A1: cg18956481, p=0.022), reflecting significant enrichment (p=0.0098).
Severe vitamin D deficiency is associated with methylation changes in leukocyte DNA. The genomic and epigenomic approach reinforce the crucial roles played by the DHCR7, CYP2R1 and CYP24A1 genes in vitamin D metabolism.
PMCID: PMC3935318  PMID: 23219444
Vitamin D deficiency; DNA methylation; genome-wide association study; African Americans; extreme phenotypes
7.  Identification of seven loci affecting mean telomere length and their association with disease 
Codd, Veryan | Nelson, Christopher P. | Albrecht, Eva | Mangino, Massimo | Deelen, Joris | Buxton, Jessica L. | Jan Hottenga, Jouke | Fischer, Krista | Esko, Tõnu | Surakka, Ida | Broer, Linda | Nyholt, Dale R. | Mateo Leach, Irene | Salo, Perttu | Hägg, Sara | Matthews, Mary K. | Palmen, Jutta | Norata, Giuseppe D. | O’Reilly, Paul F. | Saleheen, Danish | Amin, Najaf | Balmforth, Anthony J. | Beekman, Marian | de Boer, Rudolf A. | Böhringer, Stefan | Braund, Peter S. | Burton, Paul R. | de Craen, Anton J. M. | Denniff, Matthew | Dong, Yanbin | Douroudis, Konstantinos | Dubinina, Elena | Eriksson, Johan G. | Garlaschelli, Katia | Guo, Dehuang | Hartikainen, Anna-Liisa | Henders, Anjali K. | Houwing-Duistermaat, Jeanine J. | Kananen, Laura | Karssen, Lennart C. | Kettunen, Johannes | Klopp, Norman | Lagou, Vasiliki | van Leeuwen, Elisabeth M. | Madden, Pamela A. | Mägi, Reedik | Magnusson, Patrik K.E. | Männistö, Satu | McCarthy, Mark I. | Medland, Sarah E. | Mihailov, Evelin | Montgomery, Grant W. | Oostra, Ben A. | Palotie, Aarno | Peters, Annette | Pollard, Helen | Pouta, Anneli | Prokopenko, Inga | Ripatti, Samuli | Salomaa, Veikko | Suchiman, H. Eka D. | Valdes, Ana M. | Verweij, Niek | Viñuela, Ana | Wang, Xiaoling | Wichmann, H.-Erich | Widen, Elisabeth | Willemsen, Gonneke | Wright, Margaret J. | Xia, Kai | Xiao, Xiangjun | van Veldhuisen, Dirk J. | Catapano, Alberico L. | Tobin, Martin D. | Hall, Alistair S. | Blakemore, Alexandra I.F. | van Gilst, Wiek H. | Zhu, Haidong | Erdmann, Jeanette | Reilly, Muredach P. | Kathiresan, Sekar | Schunkert, Heribert | Talmud, Philippa J. | Pedersen, Nancy L. | Perola, Markus | Ouwehand, Willem | Kaprio, Jaakko | Martin, Nicholas G. | van Duijn, Cornelia M. | Hovatta, Iiris | Gieger, Christian | Metspalu, Andres | Boomsma, Dorret I. | Jarvelin, Marjo-Riitta | Slagboom, P. Eline | Thompson, John R. | Spector, Tim D. | van der Harst, Pim | Samani, Nilesh J.
Nature genetics  2013;45(4):422-427e2.
Inter-individual variation in mean leukocyte telomere length (LTL) is associated with cancer and several age-associated diseases. Here, in a genome-wide meta-analysis of 37,684 individuals with replication of selected variants in a further 10,739 individuals, we identified seven loci, including five novel loci, associated with mean LTL (P<5x10−8). Five of the loci contain genes (TERC, TERT, NAF1, OBFC1, RTEL1) that are known to be involved in telomere biology. Lead SNPs at two loci (TERC and TERT) associate with several cancers and other diseases, including idiopathic pulmonary fibrosis. Moreover, a genetic risk score analysis combining lead variants at all seven loci in 22,233 coronary artery disease cases and 64,762 controls showed an association of the alleles associated with shorter LTL with increased risk of CAD (21% (95% CI: 5–35%) per standard deviation in LTL, p=0.014). Our findings support a causal role of telomere length variation in some age-related diseases.
PMCID: PMC4006270  PMID: 23535734
8.  Precise Gene Modification Mediated by TALEN and Single-Stranded Oligodeoxynucleotides in Human Cells 
PLoS ONE  2014;9(4):e93575.
The development of human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) facilitates in vitro studies of human disease mechanisms, speeds up the process of drug screening, and raises the feasibility of using cell replacement therapy in clinics. However, the study of genotype-phenotype relationships in ESCs or iPSCs is hampered by the low efficiency of site-specific gene editing. Transcription activator-like effector nucleases (TALENs) spurred interest due to the ease of assembly, high efficiency and faithful gene targeting. In this study, we optimized the TALEN design to maximize its genomic cutting efficiency. We showed that using optimized TALENs in conjunction with single-strand oligodeoxynucleotide (ssODN) allowed efficient gene editing in human cells. Gene mutations and gene deletions for up to 7.8 kb can be accomplished at high efficiencies. We established human tumor cell lines and H9 ESC lines with homozygous deletion of the microRNA-21 (miR-21) gene and miR-9-2 gene. These cell lines provide a robust platform to dissect the roles these genes play during cell differentiation and tumorigenesis. We also observed that the endogenous homologous chromosome can serve as a donor template for gene editing. Overall, our studies demonstrate the versatility of using ssODN and TALEN to establish genetically modified cells for research and therapeutic application.
PMCID: PMC3972112  PMID: 24691488
9.  Neuronal apoptosis in cerebral ischemia/reperfusion area following electrical stimulation of fastigial nucleus 
Neural Regeneration Research  2014;9(7):727-734.
Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/reperfusion area, and decrease the number of apoptotic neurons. However, the anti-apoptotic mechanism of Ku70 remains unclear. In this study, fastigial nucleus stimulation was given to rats 24, 48, and 72 hours before cerebral ischemia/reperfusion injury. Results from the electrical stimulation group revealed that rats exhibited a reduction in brain infarct size, a significant increase in the expression of Ku70 in cerebral ischemia/reperfusion regions, and a decreased number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells. Double immunofluorescence staining revealed no co-localization of Ku70 with TUNEL-positive cells. However, Ku70 partly co-localized with Bax protein in the cytoplasm of rats with cerebral ischemia/reperfusion injury. These findings suggest an involvement of Ku70 with Bax in the cytoplasm of rats exposed to electrical stimulation of the cerebellar fastigial nucleus, and may thus provide an understanding into the anti-apoptotic activity of Ku70 in cerebral ischemia/reperfusion injury.
PMCID: PMC4146268  PMID: 25206880
nerve regeneration; brain injury; apoptosis; Ku70; Bax; electrical stimulation; fastigial nucleus; cerebral ischemia/reperfusion injury; DNA repair; NSFC grant; neural regeneration
10.  Accurate and Economical Detection of ALK Positive Lung Adenocarcinoma with Semiquantitative Immunohistochemical Screening 
PLoS ONE  2014;9(3):e92828.
Right detection of anaplastic lymphoma kinase (ALK) gene rearrangement is pivotal to selection of patients with lung adenocarcinoma for ALK-targeted therapy. We explored the potential of combination of immunohistochemistry (IHC) screening and fluorescence in situ hybridization (FISH) as an affordable practice. We analyzed 410 unselected lung adenocarcinomas by ALK IHC (D5F3 clone) and FISH. Some equivocal cases were further analyzed by RT-PCR. The EGFR mutation was detected by pyrosequencing assay. In total 368 cases which got all IHC, FISH, EGFR mutation results were eligible for analysis. Cases were evaluated as IHC score 3+ (n = 26), score 2+ (n = 9), score 1+ (n = 51), and score 0 (n = 282), respectively. 23 of 26 IHC 3+ and 5 of 9 IHC 2+ cases were FISH positive, whereas 3 of 26 IHC 3+, 4 of 9 IHC 2+ and all 333 IHC 1+/0 cases were FISH negative. If considering FISH as the standard, the sensitivity and specificity of ALK IHC 3+/2+ as ALK positive were 100% and 97.9%, respectively. Three IHC 3+ cases reported as FISH “negative” were actually ALK positive confirmed by ALK RT-PCR or re-detected. Based on the final classify, ALK IHC 3+/2+ was 100% sensitive and 98.8% specific. However, FISH was 90.3% sensitive and 100% specific. IHC 2+ was regarded as equivocal and need to be confirmed by FISH or RT-PCR. In the 368 cases, 8.4% cases had ALK positive, 52.2% cases had EGFR mutation, and only one case had a coexisting. Manually semiquantitative ALK IHC (primary antibody D5F3 coupled with secondary DAKO Envision system) used as the initial screening combined with auxiliary FISH confirmation is a reliable, economical approach to identify ALK positive lung adenocarcinoma. The IHC can find some ALK positive cases which would be missed by FISH only.
PMCID: PMC3965450  PMID: 24667320
11.  Identification, expression and interaction analyses of calcium-dependent protein kinase (CPK) genes in canola (Brassica napus L.) 
BMC Genomics  2014;15:211.
Canola (Brassica napus L.) is one of the most important oil-producing crops in China and worldwide. The yield and quality of canola is frequently threatened by environmental stresses including drought, cold and high salinity. Calcium is a well-known ubiquitous intracellular secondary messenger in plants. Calcium-dependent protein kinases (CPKs) are Ser/Thr protein kinases found only in plants and some protozoans. CPKs are Ca2+ sensors that have both Ca2+ sensing function and kinase activity within a single protein and play crucial roles in plant development and responses to various environmental stresses.
In this study, we mined the available expressed sequence tags (ESTs) of B. napus and identified a total of 25 CPK genes, among which cDNA sequences of 23 genes were successfully cloned from a double haploid cultivar of canola. Phylogenetic analysis demonstrated that they could be clustered into four subgroups. The subcellular localization of five selected BnaCPKs was determined using green fluorescence protein (GFP) as the reporter. Furthermore, the expression levels of 21 BnaCPK genes in response to salt, drought, cold, heat, abscisic acid (ABA), low potassium (LK) and oxidative stress were studied by quantitative RT-PCR and were found to respond to multiple stimuli, suggesting that canola CPKs may be convergence points of different signaling pathways. We also identified and cloned five and eight Clade A basic leucine zipper (bZIP) and protein phosphatase type 2C (PP2C) genes from canola and, using yeast two-hybrid and bimolecular fluorescence complementation (BiFC), determined the interaction between individual BnaCPKs and BnabZIPs or BnaPP2Cs (Clade A). We identified novel, interesting interaction partners for some of the BnaCPK proteins.
We present the sequences and characterization of CPK gene family members in canola for the first time. This work provides a foundation for further crop improvement and improved understanding of signal transduction in plants.
PMCID: PMC4000008  PMID: 24646378
Abiotic stress; Basic leucine zipper transcription factor; Brassica napus; Calcium-dependent protein kinase; Protein phosphatase 2C
12.  The sequence and de novo assembly of the giant panda genome 
Li, Ruiqiang | Fan, Wei | Tian, Geng | Zhu, Hongmei | He, Lin | Cai, Jing | Huang, Quanfei | Cai, Qingle | Li, Bo | Bai, Yinqi | Zhang, Zhihe | Zhang, Yaping | Wang, Wen | Li, Jun | Wei, Fuwen | Li, Heng | Jian, Min | Li, Jianwen | Zhang, Zhaolei | Nielsen, Rasmus | Li, Dawei | Gu, Wanjun | Yang, Zhentao | Xuan, Zhaoling | Ryder, Oliver A. | Leung, Frederick Chi-Ching | Zhou, Yan | Cao, Jianjun | Sun, Xiao | Fu, Yonggui | Fang, Xiaodong | Guo, Xiaosen | Wang, Bo | Hou, Rong | Shen, Fujun | Mu, Bo | Ni, Peixiang | Lin, Runmao | Qian, Wubin | Wang, Guodong | Yu, Chang | Nie, Wenhui | Wang, Jinhuan | Wu, Zhigang | Liang, Huiqing | Min, Jiumeng | Wu, Qi | Cheng, Shifeng | Ruan, Jue | Wang, Mingwei | Shi, Zhongbin | Wen, Ming | Liu, Binghang | Ren, Xiaoli | Zheng, Huisong | Dong, Dong | Cook, Kathleen | Shan, Gao | Zhang, Hao | Kosiol, Carolin | Xie, Xueying | Lu, Zuhong | Zheng, Hancheng | Li, Yingrui | Steiner, Cynthia C. | Lam, Tommy Tsan-Yuk | Lin, Siyuan | Zhang, Qinghui | Li, Guoqing | Tian, Jing | Gong, Timing | Liu, Hongde | Zhang, Dejin | Fang, Lin | Ye, Chen | Zhang, Juanbin | Hu, Wenbo | Xu, Anlong | Ren, Yuanyuan | Zhang, Guojie | Bruford, Michael W. | Li, Qibin | Ma, Lijia | Guo, Yiran | An, Na | Hu, Yujie | Zheng, Yang | Shi, Yongyong | Li, Zhiqiang | Liu, Qing | Chen, Yanling | Zhao, Jing | Qu, Ning | Zhao, Shancen | Tian, Feng | Wang, Xiaoling | Wang, Haiyin | Xu, Lizhi | Liu, Xiao | Vinar, Tomas | Wang, Yajun | Lam, Tak-Wah | Yiu, Siu-Ming | Liu, Shiping | Zhang, Hemin | Li, Desheng | Huang, Yan | Wang, Xia | Yang, Guohua | Jiang, Zhi | Wang, Junyi | Qin, Nan | Li, Li | Li, Jingxiang | Bolund, Lars | Kristiansen, Karsten | Wong, Gane Ka-Shu | Olson, Maynard | Zhang, Xiuqing | Li, Songgang | Yang, Huanming | Wang, Jian | Wang, Jun
Nature  2009;463(7279):311-317.
Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.
PMCID: PMC3951497  PMID: 20010809
13.  The THO Ribonucleoprotein Complex Is Required for Stem Cell Homeostasis in the Adult Mouse Small Intestine 
Molecular and Cellular Biology  2013;33(17):3505-3514.
RNA processing and transport are mediated by cotranscriptionally assembled ribonucleoprotein (RNP) complexes. RNPs have been postulated to help specify coordinated gene expression, but the requirements for specific RNP complexes in mammalian development and tissue homeostasis have not been extensively evaluated. THO is an evolutionarily conserved RNP complex that links transcription with nuclear export. THO is not essential for Saccharomyces cerevisiae viability, but it is essential for early mouse embryonic development. Embryonic lethality has limited the characterization of THO requirements in adult tissues. To overcome this limitation, a mouse model has been generated that allows widespread inducible deletion of Thoc1, which encodes an essential protein subunit of THO. Widespread Thoc1 deletion disrupts homeostasis within the small intestine but does not have detectable effects in other epithelial tissues such as the related mucosa of the large intestine. Thoc1 loss compromises the proliferation and lineage-generating capacity of small intestinal stem cells, disrupting the supply of differentiated cells in this rapidly renewing tissue. These findings demonstrate that the effects of THO deficiency in the adult mouse are tissue and cell type dependent.
PMCID: PMC3753850  PMID: 23816884
14.  Genetic and environmental influences on blood pressure variability: a study in twins 
Journal of hypertension  2013;31(4):10.1097/HJH.0b013e32835e2a4a.
Blood pressure variability (BPV) and its reduction in response to antihypertensive treatment are predictors of clinical outcomes; however, little is known about its heritability. In this study, we examined the relative influence of genetic and environmental sources of variance of BPV and the extent to which it may depend on race or sex in young twins.
Twins were enrolled from two studies. One study included 703 white twins (308 pairs and 87 singletons) aged 18–34 years, whereas another study included 242 white twins (108 pairs and 26 singletons) and 188 black twins (79 pairs and 30 singletons) aged 12–30 years. BPV was calculated from 24-h ambulatory blood pressure recording.
Twin modeling showed similar results in the separate analysis in both twin studies and in the meta-analysis. Familial aggregation was identified for SBP variability (SBPV) and DBP variability (DBPV) with genetic factors and common environmental factors together accounting for 18–40% and 23–31% of the total variance of SBPV and DBPV, respectively. Unique environmental factors were the largest contributor explaining up to 82–77% of the total variance of SBPV and DBPV. No sex or race difference in BPV variance components was observed. The results remained the same after adjustment for 24-h blood pressure levels.
The variance in BPV is predominantly determined by unique environment in youth and young adults, although familial aggregation due to additive genetic and/or common environment influences was also identified explaining about 25% of the variance in BPV.
PMCID: PMC3848497  PMID: 23470779
blacks; blood pressure variability; heritability; meta-analysis; twin study
American journal of hypertension  2008;21(9):10.1038/ajh.2008.224.
Prostasin, a serine protease, is suggested to be a novel mechanism regulating the epithelial sodium channel expressed in the distal nephron. This study aimed to evaluate whether the human prostasin gene is a novel candidate gene underlying blood pressure (BP) elevation.
In a sample of healthy African American (AA) and European American (EA) twin subjects aged 17.6±3.3 years (n=920, 45% AAs), race-specific tagging single nucleotide polymorphisms (tSNPs) were identified to tag all the available SNPs ± 2Kb up- and downstream of the prostasin gene from HapMap at r2 of 0.8 – 1.0. Selection yielded four tSNPs in AAs and one in EAs, with one tSNP (rs12597511: C to T) present in both AAs and EAs.
For rs12597511, CT and TT genotypes exhibited higher systolic BP than CC genotype (115.9±1.1 mmHg vs. 113.7±0.6 mmHg, p=0.025 [AAs]; and 110.7±0.5 mmHg vs. 109.6±0.6 mmHg, p=0.115 [EAs]). CT and TT genotypes compared to CC genotype showed a significant increase in diastolic BP in both racial groups (62.5±0.7 mmHg vs. 60.4±0.4 mmHg, p=0.003 [AAs]; and 58.2±0.3 mmHg vs. 56.7±0.4 mmHg, p=0.007 [EAs]). Furthermore, there was an increase in radial pulse wave velocity (PWV) in subjects with CT and TT genotype as compared to those with CC genotype (6.5±0.1 vs. 6.1±0.1 m/s, p<0.0001) [EAs]; and 6.7±0.1 vs. 6.6±0.1 m/s, p=0.354 [AAs]). Analyses combining AAs and EAs consistently demonstrated a statistical significance of rs1259751 on all the phenotypes including systolic/diastolic BP, and PWV.
Genetic variation of the prostasin gene may be implicated in the development of hypertension in youths.
PMCID: PMC3812941  PMID: 18583984
Prostasin; ENaC; Polymorphisms; Blood Pressure; Arterial stiffness
16.  Neural Encoding of Acupuncture Needling Sensations: Evidence from a fMRI Study 
Deqi response, a psychophysical response characterized by a spectrum of different needling sensations, is essential for Chinese acupuncture clinical efficacy. Previous neuroimaging research works have investigated the neural correlates of an overall deqi response by summating the scores of different needling sensations. However, the roles of individual sensations in brain activity and how they interact with each other remain to be clarified. In this study, we applied fMRI to investigate the neural correlates of individual components of deqi during acupuncture on the right LV3 (Taichong) acupoint. We selected a subset of deqi responses, namely, pressure, heaviness, fullness, numbness, and tingling. Using the individual components of deqi of different subjects as covariates in the analysis of percentage change of bold signal, pressure was found to be a striking sensation, contributing to most of negative activation of a limbic-paralimbic-neocortical network (LPNN). The similar or opposite neural activity in the heavily overlapping regions is found to be responding to different needling sensations, including bilateral LPNN, right orbitofrontal cortex, and bilateral posterior parietal cortex. These findings provide the neuroimaging evidence of how the individual needle sensations interact in the brain, showing that the modulatory effects of different needling sensations contribute to acupuncture modulations of LPNN network.
PMCID: PMC3766991  PMID: 24062782
17.  Genetic influences on heart rate variability at rest and during stress 
Psychophysiology  2009;46(3):458-465.
We tested whether the heritability of heart rate variability (HRV) under stress is different from rest and its dependency on ethnicity or gender. HRV indexed by root mean square of successive differences (RMSSD) and high-frequency (HF) power was measured at rest and during 3 stressors in 427 European and 308 African American twins. No ethnic or gender differences were found for any measures. There was a nonsignificant increase in heritability of RMSSD (from 0.48 to 0.58) and HF (from 0.50 to 0.58) under stress. Up to 81% and 60% of the heritabilities of RMSSD and HF under stress could be attributed to genes influencing rest levels. The heritabilities due to genes expressed under stress were 0.11 for RMSSD and 0.23 for HF. The findings suggest that, independent of ethnicity and gender, HRV regulation at rest and under stress is largely influenced by the same genes with a small but significant contribution of stress-specific genetic effects.
PMCID: PMC3713464  PMID: 19226307
Heart rate variability; Stress; Ethnicity; Twin study
18.  Genetic influence on blood pressure measured in the office, under laboratory stress and during real life 
To determine to what extent the genetic influences on blood pressure (BP) measured in the office, under psychologically stressful conditions in the laboratory and during real life are different from each other. Office BP, BP during a video game challenge and a social stressor interview, and 24-h ambulatory BP were measured in 238 European American and 186 African American twins. BP values across the two tasks were averaged to represent stress levels. Genetic model fitting showed no ethnic or gender differences for any of the measures. The model fitting resulted in heritability estimates of 63, 75 and 71% for office, stress and 24-h systolic BP (SBP) and 59, 67 and 69% for diastolic BP (DBP), respectively. Up to 81% of the heritability of office SBP and 71% of office DBP were attributed to genes that also influenced stress BP. However, only 45% of the heritability of 24-h SBP and 49% of 24-h DBP were attributed to genes that also influence office BP. Similarly, about 39% of the heritability of 24-h SBP and 42% of 24-h DBP were attributed to genes that also influence stress BP. Substantial overlap exists between genes that influence BP measured in the office, under laboratory stress and during real life. However, significant genetic components specific to each BP measurement also exist. These findings suggest that partly different genes or sets of genes contribute to BP regulation in different conditions.
PMCID: PMC3713474  PMID: 21068740
African American; ambulatory blood pressure; heritability; stress; twin
19.  A 15-year longitudinal study on ambulatory blood pressure tracking from childhood to early adulthood 
This study evaluates the tracking stability of office blood pressure (BP), ambulatory BP (ABP), BP variability (BPV) and nocturnal BP drops (dipping) from childhood to early adulthood, and their dependence on ethnicity, gender and family history (FH) of essential hypertension (EH). Generalized estimating equations (GEEs) were used to estimate tracking coefficients for 295 European Americans and 252 African Americans, with a maximum of 12 measurements over a 15-year period. Office BP and ABP had moderate-to-relatively high tracking coefficients (r= 0.30–0.59; P≤0.001). Twenty-four hour readings tracked better than office readings for diastolic BP (DBP; 0.57 vs. 0.46, P=1.72×10−6) and pulse pressure (PP) (0.59 vs. 0.51, P=2.70×10−4), and equally well for systolic BP (SBP; 0.55 vs. 0.54, P=0.805). Daytime readings tracked better than their night-time counterparts for SBP (0.50 vs. 0.37, P=7.62×10−13), DBP (0.49 vs. 0.30, P=7.98×10−32) and PP (0.55 vs. 0.50, P=0.0061). All BPV (r=0.08–0.28; P≤0.001) and dipping measures (r=0.07–0.12; odds ratio, 1.60–1.73; P≤0.001) had low tracking coefficients. Males had significantly higher tracking stability for office SBP, DBP and ambulatory PP than females (P<0.01). Subjects with a positive FH of EH had significantly higher tracking stability for daytime and night-time DBP and dipping indexed by continuous variables than those with a negative FH (P<0.001). No significant ethnic differences were observed. The high tracking stability of 24-h ABP highlights the importance of using ambulatory BP monitoring in both research and clinical settings.
PMCID: PMC3713484  PMID: 19325561
ambulatory blood pressure; blood pressure variability; dipping; longitudinal study; tracking
20.  Genetic influences on daytime and night-time blood pressure: similarities and differences 
Journal of hypertension  2009;27(12):2358-2364.
To examine whether the genetic influences on blood pressure (BP) during night-time are different from those during daytime and the extent to which they depend on ethnicity or sex.
Ambulatory BP was measured in 240 European–American and 190 African–American twins (mean ± SD age, 17.2 ± 3.4). Individuals with night-time BP falls more than 10% of the daytime values were defined as dippers. A bivariate analysis of the daytime and the night-time BP levels, as well as a liability-threshold model of dippers vs. nondippers were used.
Bivariate model fitting showed no ethnic or sex differences for any of the measures, with heritabilities of 0.70 and 0.68 for SBP and 0.70 and 0.64 for DBP at daytime and at night-time. The genetic influences on daytime and night-time were not significantly different for SBP or DBP. The bivariate analysis also indicated that about 56 and 33% of the heritabilities of night-time SBP and DBP could be attributed to genes that also influenced daytime levels. The specific heritabilities due to genetic effects only influencing night-time values were 0.30 for SBP and 0.43 for DBP. The heritabilities of systolic and diastolic dipping were 0.59 and 0.81, respectively.
Independent of ethnicity and sex, an overlap exists between genes that influence daytime and night-time BP, as well as a significant genetic component that is specific to the night-time BP. These findings suggest that different genes or sets of genes contribute to BP regulation at daytime and night-time.
PMCID: PMC3713486  PMID: 19657283
ambulatory blood pressure monitoring; blacks; dipping; heritability; twin study
21.  A longitudinal study of blood pressure variability in African–American and European American youth 
Journal of hypertension  2010;28(4):715-722.
High blood pressure variability is increasingly used as a predictor of target-organ damage and cardiovascular events. However, little is known about blood pressure variability changes with age and its possible sociodemographic, anthropometric, and genetic moderators.
Twenty-four-hour ambulatory blood pressure was measured up to 12 times over a 15-year period in 344 European Americans and 297 African–Americans with an average age of 14 years at the initial visit. Blood pressure variability was indexed by the weighted 24-h standard deviation of ambulatory blood pressure recordings.
Both systolic and diastolic blood pressure variability increased with age and ambulatory blood pressure mean values. Men had higher levels of blood pressure variability (P<0.001) and showed steeper linear increase rates with age than women. African–Americans showed higher values of blood pressure variability (P<0.05) than European Americans. Body mass index and waist circumference were also associated with higher blood pressure variability levels (P< 0.001). Individuals with higher father’s education level showed lower blood pressure variability. In the full model which included all the above factors, ethnic difference in systolic blood pressure variability was no longer significant.
The results of the present study suggest that men and African–Americans have higher blood pressure variability than women and European Americans. Apart from these ethnicity and sex effects, blood pressure variability increases with increases in age (especially in men), ambulatory blood pressure mean values and adiposity as well as decreased socioeconomic status
PMCID: PMC3713487  PMID: 20075746
blood pressure variability; ethnicity; longitudinal study; sex; youth
22.  Deqi Sensations of Transcutaneous Electrical Nerve Stimulation on Auricular Points 
Deqi sensation, a psychophysical response characterized by a spectrum of different needling sensations, is essential for Chinese acupuncture clinical efficacy. Previous research works have investigated the component of Deqi response upon acupuncture on acupoints on the trunk and limbs. However, the characteristics of Deqi sensations of transcutaneous electrical nerve stimulation (TENS) on auricular points are seldom reported. In this study, we investigated the individual components of Deqi during TENS on auricular concha area and the superior scapha using quantitative measurements in the healthy subjects and depression patients. The most striking characteristics of Deqi sensations upon TENS on auricular points were tingling, numbness, and fullness. The frequencies of pressure, warmness, heaviness, and soreness were relatively lower. The dull pain and coolness are rare. The characteristics of Deqi were similar for the TENS on concha and on the superior scapha.
PMCID: PMC3722844  PMID: 23935663
23.  TGFβ1 and HGF protein secretion by esophageal squamous epithelial cells and stromal fibroblasts in oesophageal carcinogenesis 
Oncology Letters  2013;6(2):401-406.
Esophageal squamous cell carcinoma (ESCC) is an aggressive cancer with a poor prognosis. Cancer-associated fibroblasts (CAFs) affect tumorigenesis by creating an environment primed for growth and invasion through the secretion of factors, including hepatocyte growth factor (HGF) and transforming growth factor β1 (TGFβ1). In the present study, the levels of α-smooth muscle actin (α-SMA), TGFβ1 and HGF were determined immunohistochemically in oesophageal precancerous lesions (low- and high-grade intraepithelial neoplasia; LGIEN and HGIEN, respectively), carcinoma in situ (CIS) and squamous cell carcinoma (SCC). Immunoreactivity was observed in the cytoplasm of oesophageal epithelial cells and stromal fibroblasts. Expression levels of α-SMA, TGFβ1 and HGF increased significantly in the following order: normal, LGIEN, HGIEN, CIS and SCC. In addition, linear correlations between the expression of α-SMA, TGFβ1 and HGF and different lesions were observed. Microvessel density (MVD) was measured in all specimens and increased gradually in the normal, LGIEN, HGIEN, CIS and SCC specimens, successively. A linear correlation between MVD and pathological grade was also observed and the MVD in α-SMA-, HGF- and TGFβ1-positive groups was higher when compared with that of their negative counterparts. The results of the present study indicated that the frequent overexpression of TGFβ1 and HGF proteins, secreted by oesophageal epithelium and stromal fibroblasts, promoted the progression of oesophageal precancerous lesions via the proliferation of epithelial cells and angiogenesis, through the upregulation of vascular endothelial growth factor (VEGF) expression.
PMCID: PMC3789106  PMID: 24137336
esophageal squamous cell carcinoma; fibroblast; transforming growth factor-β1; α-smooth muscle actin; hepatocyte growth factor
24.  Heritability of Arterial Stiffness in Black- and White American Youth and Young Adults 
American journal of hypertension  2007;20(10):1065-1072.
To examine the heritability of arterial stiffness measured as pulse wave velocity (PWV) and its dependence on ethnicity, gender and blood pressure (BP).
As part of the Georgia Cardiovascular Twin Study, we measured aortoradial (radial) and aorto-dorsalis-pedis (foot) PWV in 702 twins (41% black, 49% male) aged 12 – 30 years (mean: 17.7 ± 3.3) including monozygotic and dizygotic pairs of same- as well as opposite-gender. Ethnicity and gender effects on genetic and environmental contributions to PWV were estimated by genetic model fitting.
Diastolic BP was the most important hemodynamic predictor. Best fitting models showed no ethnicity or gender differences in estimates of genetic and environmental influence and indicated substantial heritabilities of 0.43 (95% CI: 0.30–0.54) and 0.53 (95% CI: 0.42–0.62) for radial and foot PWV, respectively. Over a quarter of these heritabilities (0.19 for radial PWV, 0.14 for foot PWV) were due to genes in common with DBP as based on multivariate models.
Individual differences in arterial stiffness of youth and young adults are substantially heritable and more than 25% of this heritability is explained by genes that also influence DBP. Heritability estimates do not show any differences between blacks and whites or males and females.
PMCID: PMC3672691  PMID: 17903689
Arterial Stiffness; Heritability; Twins; ethnicity
25.  A genome-wide methylation study on obesity 
Epigenetics  2013;8(5):522-533.
Besides differential methylation, DNA methylation variation has recently been proposed and demonstrated to be a potential contributing factor to cancer risk. Here we aim to examine whether differential variability in methylation is also an important feature of obesity, a typical non-malignant common complex disease. We analyzed genome-wide methylation profiles of over 470,000 CpGs in peripheral blood samples from 48 obese and 48 lean African-American youth aged 14–20 y old. A substantial number of differentially variable CpG sites (DVCs), using statistics based on variances, as well as a substantial number of differentially methylated CpG sites (DMCs), using statistics based on means, were identified. Similar to the findings in cancers, DVCs generally exhibited an outlier structure and were more variable in cases than in controls. By randomly splitting the current sample into a discovery and validation set, we observed that both the DVCs and DMCs identified from the first set could independently predict obesity status in the second set. Furthermore, both the genes harboring DMCs and the genes harboring DVCs showed significant enrichment of genes identified by genome-wide association studies on obesity and related diseases, such as hypertension, dyslipidemia, type 2 diabetes and certain types of cancers, supporting their roles in the etiology and pathogenesis of obesity. We generalized the recent finding on methylation variability in cancer research to obesity and demonstrated that differential variability is also an important feature of obesity-related methylation changes. Future studies on the epigenetics of obesity will benefit from both statistics based on means and statistics based on variances.
PMCID: PMC3741222  PMID: 23644594
African-Americans; epigenome-wide association study (EWAS); genome-wide association study (GWAS); methylation variation; obesity

Results 1-25 (65)