Genome-wide association with C-reactive protein levels in CLHNS: evidence for the CRP and HNF1A loci and their interaction with exposure to a pathogenic environment

Three common assumptions about inflammation, aging, and health that are probably wrong

Chronic inflammation contributes to the onset and progression of cardiovascular disease and other degenerative diseases of aging. But does it have to? This article considers the associations among inflammation, aging, and health through the lens of human population biology and suggests that chronic inflammation is not a normal nor inevitable component of aging. It is commonly assumed that conclusions drawn from research in affluent, industrialized countries can be applied globally; that aging processes leading to morbidity and mortality begin in middle age; and that inflammation is pathological. These foundational assumptions have shifted focus away from inflammation as a beneficial response to infection or injury and toward an understanding of inflammation as chronic, dysregulated, and dangerous. Findings from community-based studies around the world-many conducted in areas with relatively high burdens of infectious disease-challenge these assumptions by documenting substantial variation in levels of inflammation and patterns of association with disease. They also indicate that nutritional, microbial, and psychosocial environments in infancy and childhood play important roles in shaping inflammatory phenotypes and their contributions to diseases of aging. A comparative, developmental, and ecological approach has the potential to generate novel insights into the regulation of inflammation and how it relates to human health over the life course.

Human gain-of-function variants in HNF1A confer protection from diabetes but independently increase hepatic secretion of atherogenic lipoproteins

Loss-of-function mutations in hepatocyte nuclear factor 1A (HNF1A) are known to cause rare forms of diabetes and alter hepatic physiology through unclear mechanisms. In the general population, 1:100 individuals carry a rare, protein-coding HNF1A variant, most of unknown functional consequence. To characterize the full allelic series, we performed deep mutational scanning of 11,970 protein-coding HNF1A variants in human hepatocytes and clinical correlation with 553,246 exome-sequenced individuals. Surprisingly, we found that ∼1:5 rare protein-coding HNF1A variants in the general population cause molecular gain of function (GOF), increasing the transcriptional activity of HNF1A by up to 50% and conferring protection from type 2 diabetes (odds ratio [OR] = 0.77, p = 0.007). Increased hepatic expression of HNF1A promoted a pro-atherogenic serum profile mediated in part by enhanced transcription of risk genes including ANGPTL3 and PCSK9. In summary, ∼1:300 individuals carry a GOF variant in HNF1A that protects carriers from diabetes but enhances hepatic secretion of atherogenic lipoproteins.

Fruit and Vegetable Consumption Interacts With HNF1A Variants on the C-Reactive Protein

Epidemiological studies have demonstrated the inverse association between the intake of fruits and vegetables and inflammation. However, the mechanisms by which inflammation-related genes interact with fruit and vegetable intake and the role of these combinations in inflammation remain unclear. Therefore, we assessed the effect of interactions between fruit and vegetable intake and the hepatic nuclear factor 1 alpha (HNF1A) genetic variants on the C-reactive protein (CRP) levels. Baseline data from the Ansan and Ansung Cohort Study of the Korean Genome and Epidemiology Study (KoGES) were used. A total of 7,634 participants (3,700 men and 3,934 women) were included in the analyses. Fruit and vegetable intake was assessed using semi-quantitative food frequency questionnaire data. Genotyping information for HNF1A was extracted from the Affymetrix Genome-Wide Human SNP array 5.0. Inflammation was determined after overnight fasting by measuring CRP levels using automated analyzers. Multivariable logistic regression was used to estimate the adjusted odds ratio (AOR) with a 95% confidence interval (CI). In the fully adjusted model, men and women with the GG genotype of HNF1A rs2393791 and high fruit intake had lower odds of elevated CRP levels compared to those with the AA genotype and low fruit intake (AOR 0.50, 95% CI 0.38–0.67; AOR 0.73, 95% CI 0.55–0.97, respectively). Men and women with the rs2393791 GG genotype and high vegetable intake had lower odds of having elevated CRP levels compared to those with the AA genotype and low fruit intake (AOR 0.57, 95% CI 0.43–0.75; AOR 0.65, 95% CI 0.49–0.86, respectively). Men and women with the GG genotype and high total fruit and vegetable intake had lower odds of having elevated CRP levels. These findings indicate that fruit and vegetable intake interacts with HNF1A genetic polymorphisms, consequently influencing the inflammation levels.

Genetic and Epigenetic Association of Hepatocyte Nuclear Factor-1α with Glycosylation in Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a complex trauma-related disorder, the etiology and underlying molecular mechanisms of which are still unclear and probably involve different (epi)genetic and environmental factors. Protein N-glycosylation is a common post-translational modification that has been associated with several pathophysiological states, including inflammation and PTSD. Hepatocyte nuclear factor-1α (HNF1A) is a transcriptional regulator of many genes involved in the inflammatory processes, and it has been identified as master regulator of plasma protein glycosylation. The aim of this study was to determine the association between N-glycan levels in plasma and immunoglobulin G, methylation at four CpG positions in the HNF1A gene, HNF1A antisense RNA 1 (HNF1A-AS1), rs7953249 and HNF1A rs735396 polymorphisms in a total of 555 PTSD and control subjects. We found significant association of rs7953249 and rs735396 polymorphisms, as well as HNF1A gene methylation at the CpG3 site, with highly branched, galactosylated and sialyated plasma N-glycans, mostly in patients with PTSD. HNF1A-AS1 rs7953249 polymorphism was also associated with PTSD; however, none of the polymorphisms were associated with HNF1A gene methylation. These results indicate a possible regulatory role of the investigated HNF1A polymorphisms with respect to the abundance of complex plasma N-glycans previously associated with proinflammatory response, which could contribute to the clinical manifestation of PTSD and its comorbidities.

HNF1A：From Monogenic Diabetes to Type 2 Diabetes and Gestational Diabetes Mellitus

Diabetes, a disease characterized by hyperglycemia, has a serious impact on the lives and families of patients as well as on society. Diabetes is a group of highly heterogeneous metabolic diseases that can be classified as type 1 diabetes (T1D), type 2 diabetes (T2D), gestational diabetes mellitus (GDM), or other according to the etiology. The clinical manifestations are more or less similar among the different types of diabetes, and each type is highly heterogeneous due to different pathogenic factors. Therefore, distinguishing between various types of diabetes and defining their subtypes are major challenges hindering the precise treatment of the disease. T2D is the main type of diabetes in humans as well as the most heterogeneous. Fortunately, some studies have shown that variants of certain genes involved in monogenic diabetes also increase the risk of T2D. We hope this finding will enable breakthroughs regarding the pathogenesis of T2D and facilitate personalized treatment of the disease by exploring the function of the signal genes involved. Hepatocyte nuclear factor 1 homeobox A (HNF1α) is widely expressed in pancreatic β cells, the liver, the intestines, and other organs. HNF1α is highly polymorphic, but lacks a mutation hot spot. Mutations can be found at any site of the gene. Some single nucleotide polymorphisms (SNPs) cause maturity-onset diabetes of the young type 3 (MODY3) while some others do not cause MODY3 but increase the susceptibility to T2D or GDM. The phenotypes of MODY3 caused by different SNPs also differ. MODY3 is among the most common types of MODY, which is a form of monogenic diabetes mellitus caused by a single gene mutation. Both T2D and GDM are multifactorial diseases caused by both genetic and environmental factors. Different types of diabetes mellitus have different clinical phenotypes and treatments. This review focuses on HNF1α gene polymorphisms, HNF1A-MODY3, HNF1A-associated T2D and GDM, and the related pathogenesis and treatment methods. We hope this review will provide a valuable reference for the precise and individualized treatment of diabetes caused by abnormal HNF1α by summarizing the clinical heterogeneity of blood glucose abnormalities caused by HNF1α mutation.

Unactivated leukocyte expression of C-reactive protein is minimal and not dependent on rs1205 genotype

C-reactive protein (CRP), a prominent component of the innate immune system, is implicated in the pathophysiology of many conditions. CRP production primarily occurs in the liver; but contributions from other tissues is unclear. The Genotype-Tissue Expression Portal shows essentially no expression in whole blood and reports in the literature are conflicting. Multiple genomic variants influence serum levels of CRP. We measured CRP mRNA expression in leukocytes and sought to determine if rs1205 genotype influences leukocyte expression. Leukocytes were obtained from 20 women differing by genotype. Quantitative, real-time PCR (RT-qPCR) detected CRP and reference gene (GAPDH) mRNA. Leukocyte expression was calculated by the 2^ΔCT method, and against a standard curve. Digital drop PCR was also used to calculate expression ratios. Student's t test and linear regression methods examined possible differences between genotypes. During 32 runs (10 replicates each), the RT-qPCR mean (SD) CRP/GAPDH ratio was 3.39 × 10^–4 (SD 1.73 × 10^–4) and 3.15 × 10^–4 (SD 1.64 × 10^–4) for TT and CC genotypes respectively, p = 0.76; and digital drop PCR results were similar. Serum CRP was not significantly different between genotypes, nor correlated with leukocyte expression. CRP is minimally expressed in unactivated leukocytes and this expression is not likely influenced by rs1205 genotype.

Leptin Gene and Leptin Receptor Gene Polymorphisms in Alcohol Use Disorder: Findings Related to Psychopathology

Comorbidity between alcohol use disorder (AUD) and other addictive and psychiatric disorders is highly prevalent and disabling; however, the underlying biological correlates are not fully understood. Leptin is a peptide hormone known for its role in energy homeostasis and food intake. Furthermore, leptin plays a key role in the activity of the hypothalamic-pituitary-adrenal (HPA) axis and of several neurotransmitter systems that regulate emotionality and behavior. However, human studies that have investigated circulating leptin levels in relation to AUD and affective disorders, such as anxiety and depression, are conflicting. Genetic-based analyses of the leptin gene (LEP) and leptin receptor gene (LEPR) have the potential of providing more insight into the potential role of the leptin system in AUD and comorbid psychopathology. The aim of the current study was to investigate whether genotypic variations at LEP and LEPR are associated with measures of alcohol use, nicotine use, anxiety, and depression, all of which represent common comorbidities with AUD. Haplotype association analyses were performed, using data from participants enrolled in screening and natural history protocols at the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Analyses were performed separately in European Americans and African Americans due to the variation in haplotype diversity for most genes between these groups. In the European American group, one LEP haplotype (EB2H4) was associated with lower odds of having a current AUD diagnosis, two LEPR haplotypes (EB7H3, EB8H3) were associated with lower cigarette pack years and two LEPR haplotypes (EB7H2, EB8H2) were associated with higher State-Trait Anxiety Inventory (STAI-T) scores. In the African American group, one LEP haplotype (AB2H8) was associated with higher cigarette pack years and one LEP haplotype (AB3H2) was associated with lower Fagerström Test for Nicotine Dependence (FTND) scores. Overall, this study found that variations in the leptin and leptin receptor genes are associated with measures of alcohol use, nicotine use, and anxiety. While this preliminary study adds support for a role of the leptin system in AUD and psychopathologies, additional studies are required to fully understand the underlying mechanisms and potential therapeutic implications of these findings.

Genome-wide Association Analysis of Proinflammatory Cytokines and Gene-lifestyle Interaction for Invasive Breast Cancer Risk: The WHI dbGaP Study

Immune-related etiologic pathways to influence invasive breast cancer risk may interact with lifestyle factors, but the interrelated molecular genetic pathways are incompletely characterized. We used data from the Women's Health Initiative Database for Genotypes and Phenotypes Study including 16,088 postmenopausal women, a population highly susceptible to inflammation, obesity, and increased risk for breast cancer. With 21,784,812 common autosomal single-nucleotide polymorphisms (SNP), we conducted a genome-wide association (GWA) gene-environment interaction (G × E) analysis in six independent GWA Studies for proinflammatory cytokines [IL6 and C-reactive protein (CRP)] and their gene-lifestyle interactions. Subsequently, we tested for the association of the GWA SNPs with breast cancer risk. In women overall and stratified by obesity status (body mass index, waist circumference, and waist-to-hip ratio) and obesity-related lifestyle factors (exercise and high-fat diet), 88 GWA SNPs in 10 loci were associated with proinflammatory cytokines: 3 associated with IL6 (1 index SNP in MAPK1 and 1 independent SNP in DEC1); 85 with CRP (3 index SNPs in CRPP1, CRP, RP11-419N10.5, HNF1A-AS1, HNF1A, and C1q2orf43; and two independent SNPs in APOE and APOC1). Of those, 27 in HNF1A-AS1, HNF1A, and C1q2orf43 displayed significantly increased risk for breast cancer. We found a number of novel top markers for CRP and IL6, which interacted with obesity factors. A substantial proportion of those SNPs' susceptibility influenced breast cancer risk. Our findings may contribute to better understanding of genetic associations between pro-inflammation and cancer and suggest intervention strategies for women who carry the risk genotypes, reducing breast cancer risk. PREVENTION RELEVANCE: The top GWA-SNPs associated with pro-inflammatory biomarkers have implications for breast carcinogenesis by interacting with obesity factors. Our findings may suggest interventions for women who carry the inflammatory-risk genotypes to reduce breast cancer risk.

Allelic Heterogeneity at the CRP Locus Identified by Whole-Genome Sequencing in Multi-ancestry Cohorts

Whole-genome sequencing (WGS) can improve assessment of low-frequency and rare variants, particularly in non-European populations that have been underrepresented in existing genomic studies. The genetic determinants of C-reactive protein (CRP), a biomarker of chronic inflammation, have been extensively studied, with existing genome-wide association studies (GWASs) conducted in >200,000 individuals of European ancestry. In order to discover novel loci associated with CRP levels, we examined a multi-ancestry population (n = 23,279) with WGS (∼38× coverage) from the Trans-Omics for Precision Medicine (TOPMed) program. We found evidence for eight distinct associations at the CRP locus, including two variants that have not been identified previously (rs11265259 and rs181704186), both of which are non-coding and more common in individuals of African ancestry (∼10% and ∼1% minor allele frequency, respectively, and rare or monomorphic in 1000 Genomes populations of East Asian, South Asian, and European ancestry). We show that the minor (G) allele of rs181704186 is associated with lower CRP levels and decreased transcriptional activity and protein binding in vitro, providing a plausible molecular mechanism for this African ancestry-specific signal. The individuals homozygous for rs181704186-G have a mean CRP level of 0.23 mg/L, in contrast to individuals heterozygous for rs181704186 with mean CRP of 2.97 mg/L and major allele homozygotes with mean CRP of 4.11 mg/L. This study demonstrates the utility of WGS in multi-ethnic populations to drive discovery of complex trait associations of large effect and to identify functional alleles in noncoding regulatory regions.

Early life growth and adult telomere length in a Filipino cohort study

OBJECTIVE

We investigated the relationship between early life growth patterns and blood telomere length (TL) in adulthood using conditional measures of lean and fat mass growth to evaluate potentially sensitive periods of early life growth.

METHODS

This study included data from 1562 individuals (53% male; age 20-22 years) participating in the Cebu Longitudinal Health and Nutrition Survey, located in metropolitan Cebu, Philippines. Primary exposures included length-for-age z-score (HAZ) and weight-for-age z-score (WAZ) at birth and conditional measures of linear growth and weight gain during four postnatal periods: 0-6, 6-12, and 12-24 months, and 24 months to 8.5 years. TL was measured at ~21 years of age. We estimated associations using linear regression.

RESULTS

The study sample had an average gestational age (38.5 ± 2 weeks) and birth size (HAZ = -0.2 ± 1.1, WAZ = -0.7 ± 1.0), but by age 8.5 years had stunted linear growth (HAZ = -2.1 ± 0.9) and borderline low weight (WAZ = -1.9 ± 1.0) relative to World Health Organization references. Heavier birth weight was associated with longer TL in early adulthood (P = .03), but this association was attenuated when maternal age at birth was included in the model (P = .07). Accelerated linear growth between 6 and 12 months was associated with longer TL in adulthood (P = .006), whereas weight gain between 12 and 24 months was associated with shorter TL in adulthood (P = .047).

CONCLUSIONS

In Cebu, individuals who were born heavier have longer TL in early adulthood, but that birthweight itself may not explain the association. Findings suggest that childhood growth is associated with the cellular senescence process in adulthood, implying early life well-being may be linked to adult health.

Genetic analysis of hsCRP in American Indians: The Strong Heart Family Study

Background

Increased serum levels of C-reactive protein (CRP), an important component of the innate immune response, are associated with increased risk of cardiovascular disease (CVD). Multiple single nucleotide polymorphisms (SNP) have been identified which are associated with CRP levels, and Mendelian randomization studies have shown a positive association between SNPs increasing CRP expression and risk of colon cancer (but thus far not CVD). The effects of individual genetic variants often interact with the genetic background of a population and hence we sought to resolve the genetic determinants of serum CRP in a number of American Indian populations.

Methods

The Strong Heart Family Study (SHFS) has serum CRP measurements from 2428 tribal members, recruited as large families from three regions of the United States. Microsatellite markers and MetaboChip defined SNP genotypes were incorporated into variance components, decomposition-based linkage and association analyses.

Results

CRP levels exhibited significant heritability (h² = 0.33 ± 0.05, p<1.3 X 10⁻²⁰). A locus on chromosome (chr) 6, near marker D6S281 (approximately at 169.6 Mb, GRCh38/hg38) showed suggestive linkage (LOD = 1.9) to CRP levels. No individual SNPs were found associated with CRP levels after Bonferroni adjustment for multiple testing (threshold <7.77 x 10⁻⁷), however, we found nominal associations, many of which replicate previous findings at the CRP, HNF1A and 7 other loci. In addition, we report association of 46 SNPs located at 7 novel loci on chromosomes 2, 5, 6(2 loci), 9, 10 and 17, with an average of 15.3 Kb between SNPs and all with p-values less than 7.2 X 10⁻⁴.

Conclusion

In agreement with evidence from other populations, these data show CRP serum levels are under considerable genetic influence; and include loci, such as near CRP and other genes, that replicate results from other ethnic groups. These findings also suggest possible novel loci on chr 6 and other chromosomes that warrant further investigation.

Identification of microsatellite markers and their application in yellow catfish (Pseudobagrus fulvidraco Richardson, 1846) population genetics of Korea

Microsatellite markers from a fresh water yellow catfish, Pseudobagrus fulvidraco, were developed by whole-genome sequencing in the Ion S5 system. Of the 40 chosen sets of microsatellite markers, with tetra-repeat and penta-repeat motifs, from a total 19,743 sequence, only 13 markers were successfully applied in 78 individual fish sampled to detect genomic variability from four natural populations of Korea. On an average, the number of alleles per marker was 6.7. The observed heterozygosity varied from 0.048 to 0.810. Twelve microsatellite markers conformed to Hardy-Weinberg equilibrium and none exhibited significant linkage disequilibrium. In yellow catfish, genetic differentiation among four natural populations was further supported by F_ST (P < 0.05) and STRUCTURE analysis. The microsatellite markers identified could facilitate genetic diversity and population structure studies and thus aid in conservation of the yellow catfish.

Discovery, fine-mapping, and conditional analyses of genetic variants associated with C-reactive protein in multiethnic populations using the Metabochip in the Population Architecture using Genomics and Epidemiology (PAGE) study

C-reactive protein (CRP) is a circulating biomarker indicative of systemic inflammation. We aimed to evaluate genetic associations with CRP levels among non-European-ancestry populations through discovery, fine-mapping and conditional analyses. A total of 30 503 non-European-ancestry participants from 6 studies participating in the Population Architecture using Genomics and Epidemiology study had serum high-sensitivity CRP measurements and ∼200 000 single nucleotide polymorphisms (SNPs) genotyped on the Metabochip. We evaluated the association between each SNP and log-transformed CRP levels using multivariate linear regression, with additive genetic models adjusted for age, sex, the first four principal components of genetic ancestry, and study-specific factors. Differential linkage disequilibrium patterns between race/ethnicity groups were used to fine-map regions associated with CRP levels. Conditional analyses evaluated for multiple independent signals within genetic regions. One hundred and sixty-three unique variants in 12 loci in overall or race/ethnicity-stratified Metabochip-wide scans reached a Bonferroni-corrected P-value <2.5E-7. Three loci have no (HACL1, OLFML2B) or only limited (PLA2G6) previous associations with CRP levels. Six loci had different top hits in race/ethnicity-specific versus overall analyses. Fine-mapping refined the signal in six loci, particularly in HNF1A. Conditional analyses provided evidence for secondary signals in LEPR, IL1RN and HNF1A, and for multiple independent signals in CRP and APOE. We identified novel variants and loci associated with CRP levels, generalized known CRP associations to a multiethnic study population, refined association signals at several loci and found evidence for multiple independent signals at several well-known loci. This study demonstrates the benefit of conducting inclusive genetic association studies in large multiethnic populations.

Reproduction predicts shorter telomeres and epigenetic age acceleration among young adult women

Evolutionary theory predicts that reproduction entails costs that detract from somatic maintenance, accelerating biological aging. Despite support from studies in human and non-human animals, mechanisms linking 'costs of reproduction' (CoR) to aging are poorly understood. Human pregnancy is characterized by major alterations in metabolic regulation, oxidative stress, and immune cell proliferation. We hypothesized that these adaptations could accelerate blood-derived cellular aging. To test this hypothesis, we examined gravidity in relation to telomere length (TL, n = 821) and DNA-methylation age (DNAmAge, n = 397) in a cohort of young (20-22 year-old) Filipino women. Age-corrected TL and accelerated DNAmAge both predict age-related morbidity and mortality, and provide markers of mitotic and non-mitotic cellular aging, respectively. Consistent with theoretical predictions, TL decreased (p = 0.031) and DNAmAge increased (p = 0.007) with gravidity, a relationship that was not contingent upon resource availability. Neither biomarker was associated with subsequent fertility (both p > 0.3), broadly consistent with a causal effect of gravidity on cellular aging. Our findings provide evidence that reproduction in women carries costs in the form of accelerated aging through two independent cellular pathways.

HNF1A variant, energy-reduced diets and insulin resistance improvement during weight loss: The POUNDS Lost trial and DIRECT

AIM

To determine whether weight-loss diets varying in macronutrients modulate the genetic effect of hepatocyte nuclear factor 1α (HNF1A) rs7957197 on weight loss and improvement of insulin resistance.

MATERIALS AND METHODS

We analysed the interaction between HNF1A rs7957197 and weight-loss diets with regard to weight loss and insulin resistance improvement among 722 overweight/obese adults from a 2-year randomized weight-loss trial, the POUNDS Lost trial. The findings were replicated in another independent 2-year weight-loss trial, the Dietary Intervention Randomized Controlled Trial (DIRECT), in 280 overweight/obese adults.

RESULTS

In the POUNDS Lost trial, we found that a high-fat diet significantly modified the genetic effect of HNF1A on weight loss and reduction in waist circumference (P for interaction = .006 and .005, respectively). Borderline significant interactions for fasting insulin and insulin resistance (P for interaction = .07 and .06, respectively) were observed. We replicated the results in DIRECT. Pooled results showed similar significant interactions with weight loss, waist circumference reduction, and improvement in fasting insulin and insulin resistance (P values for interaction = .001, .005, .02 and .03, respectively). Greater decreases in weight, waist circumference, fasting insulin level and insulin resistance were observed in participants with the T allele compared to those without the T allele in the high-fat diet group (P = .04, .03 and .01, respectively).

CONCLUSIONS

Our replicable findings provide strong evidence that individuals with the HNF1A rs7957197 T allele might obtain more benefits in weight loss and improvement of insulin resistance by choosing a hypocaloric and high-fat diet.

GWAS-Supported CRP Gene Polymorphisms and Functional Outcome of Large Artery Atherosclerotic Stroke in Han Chinese

Elevated C-reactive protein (CRP) levels increase the risk of poor functional disability in patients with ischemic stroke (IS). This study aimed to investigate the association between CRP gene polymorphisms and 3-month functional disability of large artery atherosclerotic (LAA) stroke in Han Chinese. Patients with first-ever LAA IS were prospectively enrolled in Nanjing Stroke Registry Program between August 2013 and October 2015. Five single-nucleotide polymorphisms (SNPs) (rs876537, rs2794520, rs3093059, rs7553007 and rs11265260) in CRP gene related to CRP levels in Asian by genome-wide association study were genotyped. The functional outcome at 3 months after the index stroke was assessed by the modified Rankin scale. Associations between genotypes and functional outcome of LAA IS were analyzed with logistic regression model. A total of 690 eligible patients (507 males) were evaluated. SNPs rs11265260 (multivariate-adjusted, p = 0.022), rs2794520 (multivariate-adjusted, p = 0.036) and rs3093059 (multivariate-adjusted, p = 0.027) were significantly associated with elevated CRP in acute IS. Two SNPs, rs3093059 (dominant model: adjusted OR 2.49; 95% CI 1.55-4.00; recessive model: adjusted OR 3.67; 95% CI 1.22-11.03) and rs11265260 (dominant model: adjusted OR 2.51; 95% CI 1.56-4.02; recessive model: adjusted OR 4.70; 95% CI 1.63-13.56) independently predicted 3-month poor outcome of first-ever LAA IS, after adjusting for covariates. In addition, haplotype analysis indicated that haplotype GCTGC (adjusted OR 1.76; 95% CI 1.05-2.95; p = 0.031) increased the poor outcome risk. SNPs rs3093059 and rs11265260 in CRP gene may influence the 3-month functional outcome of first-ever LAA IS in Han Chinese.

Hepatocyte nuclear factors as possible C-reactive protein transcriptional inducer in the liver and white adipose tissue of rats with experimental chronic renal failure

Inflammation related to chronic kidney disease (CKD) is an important clinical problem. We recently determined that hepatocyte nuclear factor 1α (HNF1α) was upregulated in the livers of chronic renal failure (CRF) rats—experimental model of CKD. Considering that the promoter region of gene encoding C-reactive protein (CRP) contains binding sites for HNF1α and that the loss-of-function mutation in the Hnfs1α leads to significant reduction in circulating CRP levels, we hypothesized that HNF1α can activate the Crp in CRF rats. Here, we found coordinated upregulation of genes encoding CRP, interleukin-6 (IL-6), HNF1α, and HNF4α in the livers and white adipose tissue (WAT) of CRF rats, as compared to the pair-fed and control animals. This was accompanied by elevated serum levels of CRP and IL-6. CRP and HNFs’ mRNA levels correlated positively with CRP and HNFs’ protein levels in the liver and WAT. Similar upregulation of the Crp, Il-6, and Hnfs in the liver and WAT and increased serum CRP and IL-6 concentrations were found in lipopolysaccharide (LPS)-induced systemic inflammation in rats. Moreover, silencing HNF1α in HepG2 cells by small interfering RNA led to decrease in CRP mRNA levels. Our results suggests that (a) HNFs act in concert with IL-6 in the upregulation of CRP production by the liver and WAT, leading to an increase in circulating CRP concentration in CRF rats and (b) CRF-related inflammation plays an important role in the upregulation of genes that encode HNFs and CRP in the liver and WAT of CRF rats.

Early life infection, but not breastfeeding, predicts adult blood telomere lengths in the Philippines

OBJECTIVES

Telomeres are repetitive DNA at chromosomes ends that shorten with age due to cellular replication and oxidative stress. As telomeres shorten, this can eventually place limits on cell replication and contribute to senescence. Infections are common during early development and activate cellular immune responses that involve clonal expansion and oxidative stress. As such, a high infectious disease burden might shorten blood telomere length (BTL) and accelerate the pace of immune senescence.

METHODS

To test this, BTL measured in young adults (21.7 ± 0.3 years old) from the Philippines (N = 1,759) were linked to prospectively collected early life data on infectious burden.

RESULTS

As predicted, increased early life diarrheal prevalence was associated with shorter adult BTL. The association was most marked for infections experienced from 6 to 12 months, which corresponds with weaning and maximal diarrheal burden. A standard deviation increase in infections at 6-12 m predicts a 45 bp decrease in BTL, equivalent to 3.3 years of adult telomeric aging in this population. Contrary to expectations, breastfeeding duration was not associated with BTL, nor did effects vary by sex.

CONCLUSIONS

These findings show that infancy diarrheal disease predicts a marker of cellular aging in adult immune cells. These findings suggest that early life infectious burden may influence late life health, or alternatively, that short TL in early life increases infectious disease susceptibility.

Social and physical environments early in development predict DNA methylation of inflammatory genes in young adulthood

Chronic inflammation contributes to a wide range of human diseases, and environments in infancy and childhood are important determinants of inflammatory phenotypes. The underlying biological mechanisms connecting early environments with the regulation of inflammation in adulthood are not known, but epigenetic processes are plausible candidates. We tested the hypothesis that patterns of DNA methylation (DNAm) in inflammatory genes in young adulthood would be predicted by early life nutritional, microbial, and psychosocial exposures previously associated with levels of inflammation. Data come from a population-based longitudinal birth cohort study in metropolitan Cebu, the Philippines, and DNAm was characterized in whole blood samples from 494 participants (age 20-22 y). Analyses focused on probes in 114 target genes involved in the regulation of inflammation, and we identified 10 sites across nine genes where the level of DNAm was significantly predicted by the following variables: household socioeconomic status in childhood, extended absence of a parent in childhood, exposure to animal feces in infancy, birth in the dry season, or duration of exclusive breastfeeding. To evaluate the biological significance of these sites, we tested for associations with a panel of inflammatory biomarkers measured in plasma obtained at the same age as DNAm assessment. Three sites predicted elevated inflammation, and one site predicted lower inflammation, consistent with the interpretation that levels of DNAm at these sites are functionally relevant. This pattern of results points toward DNAm as a potentially important biological mechanism through which developmental environments shape inflammatory phenotypes across the life course.

Pancreatic Cancer Risk Associated with Prediagnostic Plasma Levels of Leptin and Leptin Receptor Genetic Polymorphisms

Leptin is an adipokine involved in regulating energy balance, which has been identified as a potential biologic link in the development of obesity-associated cancers, such as pancreatic cancer. In this prospective, nested case-control study of 470 cases and 1,094 controls from five U.S. cohorts, we used conditional logistic regression to evaluate pancreatic cancer risk by prediagnostic plasma leptin, adjusting for race/ethnicity, diabetes, body mass index, physical activity, plasma C-peptide, adiponectin, and 25-hydroxyvitamin D. Because of known differences in leptin levels by gender, analyses were conducted separately for men and women. We also evaluated associations between 32 tagging SNPs in the leptin receptor (LEPR) gene and pancreatic cancer risk. Leptin levels were higher in female versus male control participants (median, 20.8 vs. 6.7 ng/mL; P < 0.0001). Among men, plasma leptin was positively associated with pancreatic cancer risk and those in the top quintile had a multivariable-adjusted OR of 3.02 [95% confidence interval (CI), 1.27-7.16; P_trend = 0.02] compared with men in the bottom quintile. Among women, circulating leptin was not associated with pancreatic cancer risk (P_trend = 0.21). Results were similar across cohorts (P_{heterogeneity} = 0.88 for two male cohorts and 0.35 for three female cohorts). In genetic analyses, rs10493380 in LEPR was associated with increased pancreatic cancer risk among women, with an OR per minor allele of 1.54 (95% CI, 1.18-2.02; multiple hypothesis-corrected P = 0.03). No SNPs were significantly associated with risk in men. In conclusion, higher prediagnostic levels of plasma leptin were associated with an elevated risk of pancreatic cancer among men, but not among women. Cancer Res; 76(24); 7160-7. ©2016 AACR.

Androgen receptor CAG repeat polymorphism and hypothalamic-pituitary-gonadal function in Filipino young adult males

OBJECTIVES

Testosterone (T), the primary androgenic hormone in males, is stimulated through pulsatile secretion of LH and regulated through negative feedback inhibition at the hypothalamus and pituitary. The hypothalamic-pituitary-gonadal (HPG) axis also controls sperm production through the secretion of follicle-stimulating hormone (FSH). Negative feedback in the HPG axis is achieved in part through the binding of T to the androgen receptor (AR), which contains a highly variable trinucleotide repeat polymorphism (AR-CAGn). The number of repeats in the AR-CAGn inversely correlates with transcriptional activity of the AR. Thus, we predicted longer AR-CAGn to be associated with higher T, LH, and FSH levels.

METHODS

We examined the relationship between AR-CAGn and total plasma T, LH, and FSH, as well as "bioavailable" morning (AM-T) and evening (PM-T) testosterone in 722 young (21.5 ± 0.5 years) Filipino males.

RESULTS

There was no relationship between AR-CAGn and total T, AM-T, or LH (P > .25 for all). We did observe a marginally non-significant (P = .066) correlation between AR-CAGn and PM-T in the predicted direction, and a negative correlation between AR-CAGn and FSH (P = .005).

CONCLUSIONS

Our results both support and differ from previous findings in this area, and study parameters that differ between our study and others, such as participant age, sample time, and the role of other hormones should be considered when interpreting our findings. While our data point to a modest effect of AR-CAGn on HPG regulation at best, the AR-CAGn may still affect somatic traits by regulating androgenic activity at peripheral tissues.

Immune function in Amazonian horticulturalists

BACKGROUND

Amazonian populations are exposed to diverse parasites and pathogens, including protozoal, bacterial, fungal and helminthic infections. Yet much knowledge of the immune system is based on industrialised populations where these infections are relatively rare.

AIM

This study examines distributions and age-related differences in 22 measures of immune function for Bolivian forager-horticulturalists and US and European populations.

SUBJECTS AND METHODS

Subjects were 6338 Tsimane aged 0-90 years. Blood samples collected between 2004-2014 were analysed for 5-part blood differentials, C-reactive protein, erythrocyte sedimentation rate (ESR) and total immunoglobulins E, G, A and M. Flow cytometry was used to quantify naïve and non-naïve CD4 and CD8 T cells, natural killer cells, and B cells.

RESULTS

Compared to reference populations, Tsimane have elevated levels of most immunological parameters, particularly immunoglobulins, eosinophils, ESR, B cells, and natural killer cells. However, monocytes and basophils are reduced and naïve CD4 cells depleted in older age groups.

CONCLUSION

Tsimane ecology leads to lymphocyte repertoires and immunoglobulin profiles that differ from those observed in industrialised populations. These differences have consequences for disease susceptibility and co-vary with patterns of other life history traits, such as growth and reproduction.

Shared genetic susceptibility of vascular-related biomarkers with ischemic and recurrent stroke

OBJECTIVE

To investigate the genetic contributors to cerebrovascular disease and variation in biomarkers of ischemic stroke.

METHODS

The Vitamin Intervention for Stroke Prevention Trial (VISP) was a randomized, controlled clinical trial of B vitamin supplementation to prevent recurrent stroke, myocardial infarction, or death. VISP collected baseline measures of C-reactive protein (CRP), fibrinogen, creatinine, prothrombin fragments F1+2, thrombin-antithrombin complex, and thrombomodulin prior to treatment initiation. Genome-wide association scans were conducted for these traits and follow-up replication analyses were performed.

RESULTS

We detected an association between CRP single nucleotide polymorphisms (SNPs) and circulating CRP levels (most associated SNP, rs2592902, p = 1.14 × 10(-9)) in 2,100 VISP participants. We discovered a novel association for CRP level in the AKR1D1 locus (rs2589998, p = 7.3 × 10(-8), approaching genome-wide significance) that also is an expression quantitative trait locus for CRP gene expression. We replicated previously identified associations of fibrinogen with SNPs in the FGB and LEPR loci. CRP-associated SNPs and CRP levels were significantly associated with risk of ischemic stroke and recurrent stroke in VISP as well as specific stroke subtypes in METASTROKE. Fibrinogen levels but not fibrinogen-associated SNPs were also found to be associated with recurrent stroke in VISP.

CONCLUSIONS

Our data identify a genetic contribution to inflammatory and hemostatic biomarkers in a stroke population. Additionally, our results suggest shared genetic contributions to circulating CRP levels measured poststroke and risk for incident and recurrent ischemic stroke. These data broaden our understanding of genetic contributors to biomarker variation and ischemic stroke risk, which should be useful in clinical risk evaluation.

No association between blood telomere length and longitudinally assessed diet or adiposity in a young adult Filipino population

PURPOSE

Telomeres, DNA-protein structures that cap and protect chromosomes, are thought to shorten more rapidly when exposed to chronic inflammation and oxidative stress. Diet and nutritional status may be a source of inflammation and oxidative stress. However, relationships between telomere length (TL) and diet or adiposity have primarily been studied cross-sectionally among older, overweight/obese populations and yielded inconsistent results. Little is known about the relationship between diet or body composition and TL among younger, low- to normal-weight populations. It also remains unclear how cumulative exposure to a specific diet or body composition during the years of growth and development, when telomere attrition is most rapid, may be related to TL in adulthood.

METHODS

In a sample of 1459 young adult Filipinos, we assessed the relationship between blood TL at ages 20.8-22.5 and measures of BMI z-score, waist circumference, and diet collected between the ages of 8.5 and 22.5. TL was measured using monochrome multiplex quantitative PCR, and diet was measured using multiple 24-h recalls.

RESULTS

We found no associations between blood TL and any of the measures of adiposity or between blood TL and the seven dietary factors examined: processed meats, fried/grilled meats and fish, non-fried fish, coconut oil, fruits and vegetables, bread and bread products, and sugar-sweetened beverages.

CONCLUSIONS

Considering the inconsistencies in the literature and our null results, small differences in body composition and consumption of any single pro- or anti-inflammatory dietary component may not by themselves have a meaningful impact on telomere integrity, or the impact may differ across distinct ecological circumstances.

C-reactive protein gene variants associated with recurrent pregnancy loss independent of CRP serum levels: a case-control study

The aim of this study is to investigate the association of recurrent pregnancy loss (RPL) with altered C-reactive protein (CRP) serum levels, and genetic variation in CRP gene. This was a retrospective case-control study, involving 275 women with three or more consecutive pregnancy losses, and 290 age-matched control women, who were recruited from outpatient obstetrics/gynecology clinics. CRP serum levels (hs-CRP) were determined by latex-enhanced nephelometry, and CRP genotyping was done by allelic discrimination. Mean serum CRP levels were higher in RPL cases than in control women, and carriage of the (minor) T allele of rs2794520 was associated with significant increase in CRP levels (P=0.017). Minor allele frequency (MAF) of rs7553007 was significantly different between RPL cases and control women, and was associated with reduced risk of RPL after adjusting for BMI and menarche. There was a significant enrichment of minor allele-carrying genotypes of rs1130864 and rs1417938 SNPs, and reduced frequency of minor allele-carrying genotypes of rs876537, rs2794520, and rs7553007 in RPL cases, thus assigning RPL-susceptible and -protective nature to these genotypes, respectively. Carriage of (minor) T allele of only rs2794520 was associated with significant increase in CRP levels. CRP variants that influenced circulating CRP levels in chronic inflammatory conditions are also associated with RPL, pointing to CRP as RPL candidate gene.

Common variants in the CRP promoter are associated with a high C-reactive protein level in Kawasaki disease

Kawasaki disease (KD) is an acute self-limiting form of vasculitis that afflicts infants and children and manifests as fever and signs of mucocutaneous inflammation. Children with KD show various laboratory inflammatory abnormalities, such as elevations in their white blood cell (WBC) count, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR). We here performed a genome-wide association study (GWAS) of 178 KD patients to identify the genetic loci that influence 10 important KD laboratory markers: WBC count, neutrophil count, platelet count, CRP, ESR, hemoglobin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, and total protein. A total of 165 loci passed our arbitrary stage 1 threshold for replication (p < 1 × 10(-5)). Of these, only 2 SNPs (rs12068753 and rs4786091) demonstrated a significant association with the CRP level in replication study of 473 KD patients (p < 0.05). The SNP located at the CRP locus (rs12068753) demonstrated the most significant association with CRP in KD patients (beta = 4.73 and p = 1.20 × 10(-6) according to the stage 1 GWAS; beta = 3.65 and p = 1.35 × 10(-8) according to the replication study; beta = 3.97 and p = 1.11 × 10(-13) according to combined analysis) and explained 8.1% of the phenotypic variation observed. However, this SNP did not demonstrate any significant association with CRP in the general population (beta = 0.37 and p = 0.1732) and only explained 0.1% of the phenotypic variation in this instance. Furthermore, rs12068753 did not affect the development of coronary artery lesions or intravenous immunoglobulin resistance in KD patients. These results indicate that common variants in the CRP promoter can play an important role in the CRP levels in KD.

Novel locus for fibrinogen in 3' region of LEPR gene in island population of Vis (Croatia)

Leptin, a possible mediator between energy homeostasis, inflammation and cardiovascular disease (CVD), acts via leptin receptors. We investigated association of single-nucleotide polymorphisms (SNPs) and haplotypes of the leptin receptor gene (LEPR) with several CVD risk factors: body mass index, waist circumference (WC), serum lipids, fibrinogen and C-reactive protein levels. Thirty-one SNPs in and near LEPR gene were analyzed in 986 inhabitants of the island of Vis, Croatia and 29 SNPs in the inland sample (N=499). We assessed linkage disequilibrium (LD), SNP and haplotype associations with the selected phenotypes. rs4291477 significantly associated with fibrinogen (P=0.003) and rs7539471 marginally significantly with high-density lipoprotein (P=0.004), but only in the Vis sample, while rs10493384 marginally significantly associated with triglyceride levels (P=0.006) in the inland sample. SNPs were grouped into eight LD blocks in Vis and in seven blocks in the inland population. Haplotype A-C-A-A-G-A in block 5 in Vis (rs1782754, rs1171269, rs1022981, rs6673324, rs3790426, rs10493380) and haplotype A-A-A-A in block 4 in the inland data (rs1782754, rs1022981, rs6673324, rs1137100) were nominally associated with WC, P=7.085 × 10(-22) (adjusted P=0.0979) and P=5.496 × 10(-144) (adjusted P=0.1062), respectively.

Association of exome sequences with plasma C-reactive protein levels in >9000 participants

C-reactive protein (CRP) concentration is a heritable systemic marker of inflammation that is associated with cardiovascular disease risk. Genome-wide association studies have identified CRP-associated common variants associated in ∼25 genes. Our aims were to apply exome sequencing to (1) assess whether the candidate loci contain rare coding variants associated with CRP levels and (2) perform an exome-wide search for rare variants in novel genes associated with CRP levels. We exome-sequenced 6050 European-Americans (EAs) and 3109 African-Americans (AAs) from the NHLBI-ESP and the CHARGE consortia, and performed association tests of sequence data with measured CRP levels. In single-variant tests across candidate loci, a novel rare (minor allele frequency = 0.16%) CRP-coding variant (rs77832441-A; p.Thr59Met) was associated with 53% lower mean CRP levels (P = 2.9 × 10(-6)). We replicated the association of rs77832441 in an exome array analysis of 11 414 EAs (P = 3.0 × 10(-15)). Despite a strong effect on CRP levels, rs77832441 was not associated with inflammation-related phenotypes including coronary heart disease. We also found evidence for an AA-specific association of APOE-ε2 rs7214 with higher CRP levels. At the exome-wide significance level (P < 5.0 × 10(-8)), we confirmed associations for reported common variants of HNF1A, CRP, IL6R and TOMM40-APOE. In gene-based tests, a burden of rare/lower frequency variation in CRP in EAs (P ≤ 6.8 × 10(-4)) and in retinoic acid receptor-related orphan receptor α (RORA) in AAs (P = 1.7 × 10(-3)) were associated with CRP levels at the candidate gene level (P < 2.0 × 10(-3)). This inquiry did not elucidate novel genes, but instead demonstrated that variants distributed across the allele frequency spectrum within candidate genes contribute to CRP levels.

Genetic risk score and adiposity interact to influence triglyceride levels in a cohort of Filipino women

Background/Objectives:

Individually, genetic variants only moderately influence cardiometabolic (CM) traits, such as lipid and inflammatory markers. In this study we generated genetic risk scores from a combination of previously reported variants influencing CM traits, and used these scores to explore how adiposity levels could mediate genetic contributions to CM traits.

Subjects/Methods:

Participants included 1649 women from the 2005 Cebu Longitudinal Health and Nutrition Survey. Three genetic risk scores were constructed for C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TGs). We used linear regression models to assess the association between each genetic risk score and its related trait. We also tested for interactions between each score and measures of adiposity.

Results:

Each genetic risk score explained a greater proportion of variance in trait levels than any individual genetic variant. We found an interaction between the TG genetic risk score (2.29–14.34 risk alleles) and waist circumference (WC) (P_interaction=1.66 × 10⁻²). Based on model predictions, for individuals with a higher TG genetic risk score (75th percentile=12), having an elevated WC (⩾80 cm) increased TG levels from 1.32 to 1.71 mmol l⁻¹. However, for individuals with a lower score (25th percentile=7), having an elevated WC did not significantly change TG levels.

Conclusions:

The TG genetic risk score interacted with adiposity to synergistically influence TG levels. For individuals with a genetic predisposition to elevated TG levels, our results suggest that reducing adiposity could possibly prevent further increases in TG levels and thereby lessen the likelihood of adverse health outcomes such as cardiovascular disease.

Multiancestral analysis of inflammation-related genetic variants and C-reactive protein in the population architecture using genomics and epidemiology study

BACKGROUND

C-reactive protein (CRP) is a biomarker of inflammation. Genome-wide association studies (GWAS) have identified single-nucleotide polymorphisms (SNPs) associated with CRP concentrations and inflammation-related traits such as cardiovascular disease, type 2 diabetes mellitus, and obesity. We aimed to replicate previous CRP-SNP associations, assess whether these associations generalize to additional race/ethnicity groups, and evaluate inflammation-related SNPs for a potentially pleiotropic association with CRP.

METHODS AND RESULTS

We selected and analyzed 16 CRP-associated and 250 inflammation-related GWAS SNPs among 40 473 African American, American Indian, Asian/Pacific Islander, European American, and Hispanic participants from 7 studies collaborating in the Population Architecture using Genomics and Epidemiology (PAGE) study. Fixed-effect meta-analyses combined study-specific race/ethnicity-stratified linear regression estimates to evaluate the association between each SNP and high-sensitivity CRP. Overall, 18 SNPs in 8 loci were significantly associated with CRP (Bonferroni-corrected P<3.1×10(-3) for replication, P<2.0×10(-4) for pleiotropy): Seven of these were specific to European Americans, while 9 additionally generalized to African Americans (1), Hispanics (5), or both (3); 1 SNP was seen only in African Americans and Hispanics. Two SNPs in the CELSR2/PSRC1/SORT1 locus showed a potentially novel association with CRP: rs599839 (P=2.0×10(-6)) and rs646776 (P=3.1×10(-5)).

CONCLUSIONS

We replicated 16 SNP-CRP associations, 10 of which generalized to African Americans and/or Hispanics. We also identified potentially novel pleiotropic associations with CRP for two SNPs previously associated with coronary artery disease and/or low-density lipoprotein-cholesterol. These findings demonstrate the benefit of evaluating genotype-phenotype associations in multiple race/ethnicity groups and looking for pleiotropic relationships among SNPs previously associated with related phenotypes.

Genetic risk assessment for cardiovascular disease with seven genes associated with plasma C-reactive protein concentrations in Asian populations

Plasma C-reactive protein (CRP) level is a predictor of cardiovascular risk. We performed a meta-analysis on the effect of 12 single-nucleotide polymorphisms (SNPs) within 8 candidate loci in 36 752 Asians. In addition, we created weighted genetic risk scores (wGRSs) to evaluate the combined effects of genetic variants, which were suggested in the meta-analysis, for predicting the risks of elevated CRP levels as well as increased risks of hypertension and cardiovascular disease (CVD) in 748 Koreans. Nine SNPs located in seven genes, CRP, IL6R, GCKR, IL6, CYP17A1, HNF1A and APOE, were significantly associated with circulating CRP levels in this meta-analysis. Two SNPs, rs7310409 (HNF1A, P=3.4 × 10(-23)) and rs7553007 (CRP, P=3.4 × 10(-17)), had the most significant effects on CRP levels; and two SNPs, rs2097677 (IL6) and rs1004467 (CYP17A1) have never been found in the previous European meta-analysis. In Koreans, the subjects in the highest wGRS group had an ∼2.5-fold higher mean CRP level compared with those in the lowest wGRS group (P=2.1 × 10(-5)). We observed significant increases in the risks of hypertension (odds ratio=2.18, P=0.006) and CVD (odds ratio=9.59, P=3.2 × 10(-6)) among the subjects in the highest wGRS group. The wGRS models specific to Koreans may warrant further validation to be used as a proxy for the risk of CVD in Asians.

Imputation of variants from the 1000 Genomes Project modestly improves known associations and can identify low-frequency variant-phenotype associations undetected by HapMap based imputation

Genome-wide association (GWA) studies have been limited by the reliance on common variants present on microarrays or imputable from the HapMap Project data. More recently, the completion of the 1000 Genomes Project has provided variant and haplotype information for several million variants derived from sequencing over 1,000 individuals. To help understand the extent to which more variants (including low frequency (1% ≤ MAF <5%) and rare variants (<1%)) can enhance previously identified associations and identify novel loci, we selected 93 quantitative circulating factors where data was available from the InCHIANTI population study. These phenotypes included cytokines, binding proteins, hormones, vitamins and ions. We selected these phenotypes because many have known strong genetic associations and are potentially important to help understand disease processes. We performed a genome-wide scan for these 93 phenotypes in InCHIANTI. We identified 21 signals and 33 signals that reached P<5×10(-8) based on HapMap and 1000 Genomes imputation, respectively, and 9 and 11 that reached a stricter, likely conservative, threshold of P<5×10(-11) respectively. Imputation of 1000 Genomes genotype data modestly improved the strength of known associations. Of 20 associations detected at P<5×10(-8) in both analyses (17 of which represent well replicated signals in the NHGRI catalogue), six were captured by the same index SNP, five were nominally more strongly associated in 1000 Genomes imputed data and one was nominally more strongly associated in HapMap imputed data. We also detected an association between a low frequency variant and phenotype that was previously missed by HapMap based imputation approaches. An association between rs112635299 and alpha-1 globulin near the SERPINA gene represented the known association between rs28929474 (MAF = 0.007) and alpha1-antitrypsin that predisposes to emphysema (P = 2.5×10(-12)). Our data provide important proof of principle that 1000 Genomes imputation will detect novel, low frequency-large effect associations.

Gene-centric analysis identifies variants associated with interleukin-6 levels and shared pathways with other inflammation markers

BACKGROUND- Inflammatory cytokine interleukin-6 (IL-6), a possible risk factor for coronary heart disease, has an estimated heritability of >60%, but to date few genetic variants influencing IL-6 levels are known. METHODS AND RESULTS- We used the ITMAT-Broad-Care (IBC) HumanCVD disease BeadChip in the Whitehall II study (N=4911) and British Women's Heart and Health Study (N=3445) to identify single-nucleotide polymorphisms associated with circulating IL-6 levels. Twenty-two single-nucleotide polymorphisms from 7 loci (IL6R/TDRD10, HLA-DRB1, BUD13, SEZ6L, IL1RN, TRIB3, and ABO) were associated with IL-6 (P<10(-5)), although none were associated with the IL6 gene itself. With the exception of TRIB3, all loci have been previously reported in genome-wide association studies for autoimmune and cardiovascular diseases. Fourteen single-nucleotide polymorphisms in the IL6R region in high-linkage disequilibrium (r(2)>0.9) with a nonsynonymous variant, rs2228145, were also associated with IL-6 and C-reactive protein concentration (P<10(-5)). An IL-6-specific weighted allele score explained 2% of the variance of log IL-6 levels (P=2.4410(-22)) in Whitehall II and 1% (P=1.910(-8)) in British Women's Heart and Health Studies. CONCLUSIONS- Multiple common genetic variants of modest effect influence IL-6 concentration. Several loci contain single-nucleotide polymorphisms, exhibiting overlapping associations with autoimmune and cardiovascular disorders and other circulating biomarkers. Genetic variants associated with IL-6 provide important tools for probing the causal relevance of IL-6 signaling in a range of cardiometabolic diseases.

Early environments and the ecology of inflammation

Recent research has implicated inflammatory processes in the pathophysiology of a wide range of chronic degenerative diseases, although inflammation has long been recognized as a critical line of defense against infectious disease. However, current scientific understandings of the links between chronic low-grade inflammation and diseases of aging are based primarily on research in high-income nations with low levels of infectious disease and high levels of overweight/obesity. From a comparative and historical point of view, this epidemiological situation is relatively unique, and it may not capture the full range of ecological variation necessary to understand the processes that shape the development of inflammatory phenotypes. The human immune system is characterized by substantial developmental plasticity, and a comparative, developmental, ecological framework is proposed to cast light on the complex associations among early environments, regulation of inflammation, and disease. Recent studies in the Philippines and lowland Ecuador reveal low levels of chronic inflammation, despite higher burdens of infectious disease, and point to nutritional and microbial exposures in infancy as important determinants of inflammation in adulthood. By shaping the regulation of inflammation, early environments moderate responses to inflammatory stimuli later in life, with implications for the association between inflammation and chronic diseases. Attention to the eco-logics of inflammation may point to promising directions for future research, enriching our understanding of this important physiological system and informing approaches to the prevention and treatment of disease.

C-reactive protein (CRP) promoter polymorphisms influence circulating CRP levels in a genome-wide association study of African Americans

C-reactive protein (CRP) is an acute phase reactant protein produced primarily by the liver. Circulating CRP levels are influenced by genetic and non-genetic factors, including infection and obesity. Genome-wide association studies (GWAS) provide an unbiased approach towards identifying loci influencing CRP levels. None of the six GWAS for CRP levels has been conducted in an African ancestry population. The present study aims to: (i) identify genetic variants that influence serum CRP in African Americans (AA) using a genome-wide association approach and replicate these findings in West Africans (WA), (ii) assess transferability of major signals for CRP reported in European ancestry populations (EA) to AA and (iii) use the weak linkage disequilibrium (LD) structure characteristic of African ancestry populations to fine-map the previously reported CRP locus. The discovery cohort comprised 837 unrelated AA, with the replication of significant single-nucleotide polymorphisms (SNPs) assessed in 486 WA. The association analysis was conducted with 2 366 856 genotyped and imputed SNPs under an additive genetic model with adjustment for appropriate covariates. Genome-wide and replication significances were set at P < 5 × 10(-8) and P < 0.05, respectively. Ten SNPs in (CRP pseudogene-1) CRPP1 and CRP genes were associated with serum CRP (P = 2.4 × 10(-09) to 4.3 × 10(-11)). All but one of the top-scoring SNPs associated with CRP in AA were successfully replicated in WA. CRP signals previously identified in EA samples were transferable to AAs, and we were able to fine-map this signal, reducing the region of interest from the 25 kb of LD around the locus in the HapMap CEU sample to only 8 kb in our AA sample.

Common variants in CRP and LEPR influence high sensitivity C-reactive protein levels in North Indians

BACKGROUND

High sensitivity C-reactive protein (hsCRP) levels are shown to be influenced by genetic variants in Europeans; however, little is explored in Indian population.

METHODS

Herein, we comprehensively evaluated association of all previously reported genetic determinants of hsCRP levels, including 18 cis (proximal to CRP gene) and 73 trans-acting (distal to CRP gene) variants in 4,200 North Indians of Indo-European ethnicity. First, we evaluated association of 91 variants from 12 candidate loci with hsCRP levels in 2,115 North Indians (1,042 non-diabetic subjects and 1,073 patients with type 2 diabetes). Then, cis and trans-acting variants contributing maximally to hsCRP level variation were further replicated in an independent 2,085 North Indians (1,047 patients with type 2 diabetes and 1,038 non-diabetic subjects).

RESULTS

We found association of 12 variants from CRP, LEPR, IL1A, IL6, and IL6R with hsCRP levels in non-diabetic subjects. However, only rs3093059-CRP [β = 0.33, P = 9.6×10⁻⁵] and the haplotype harboring rs3093059 risk allele [β = 0.32 µg/mL, P = 1.4×10⁻⁴/P(perm) = 9.0×10⁻⁴] retained significance after correcting for multiple testing. The cis-acting variant rs3093059-CRP had maximum contribution to the variance in hsCRP levels (1.14%). Among, trans-acting variants, rs1892534-LEPR was observed to contribute maximally to hsCRP level variance (0.59%). Associations of rs3093059-CRP and rs1892534-LEPR were confirmed by replication and attained higher significance after meta-analysis [β(meta) = 0.26/0.22; P(meta) = 4.3×10⁻⁷/7.4×10⁻³ and β(meta) = -0.15/-0.12; P(meta) = 2.0×10⁻⁶/1.6×10⁻⁶ for rs3093059 and rs1892534, respectively in non-diabetic subjects and all subjects taken together].

CONCLUSION

In conclusion, we identified rs3093059 in CRP and rs1892534 in LEPR as major cis and trans-acting contributor respectively, to the variance in hsCRP levels in North Indian population.