Identification of cis- and trans-acting genetic variants explaining up to half the variation in circulating vascular endothelial growth factor levels

Genetic Associations with Placental Proteins in Maternal Serum Identify Biomarkers for Hypertension in Pregnancy

Background

Preeclampsia is a complex syndrome that accounts for considerable maternal and perinatal morbidity and mortality. Despite its prevalence, no effective disease-modifying therapies are available. Maternal serum placenta-derived proteins have been in longstanding use as markers of risk for aneuploidy and placental dysfunction, but whether they have a causal contribution to preeclampsia is unknown.

Objective

We aimed to investigate the genetic regulation of serum placental proteins in early pregnancy and their potential causal links with preeclampsia and gestational hypertension.

Study design

This study used a nested case-control design with nulliparous women enrolled in the nuMoM2b study from eight clinical sites across the United States between 2010 and 2013. The first- and second-trimester serum samples were collected, and nine proteins were measured, including vascular endothelial growth factor (VEGF), placental growth factor, endoglin, soluble fms-like tyrosine kinase-1 (sFlt-1), a disintegrin and metalloproteinase domain-containing protein 12 (ADAM-12), pregnancy-associated plasma protein A, free beta-human chorionic gonadotropin, inhibin A, and alpha-fetoprotein. This study used genome-wide association studies to discern genetic influences on these protein levels, treating proteins as outcomes. Furthermore, Mendelian randomization was used to evaluate the causal effects of these proteins on preeclampsia and gestational hypertension, and their further causal relationship with long-term hypertension, treating proteins as exposures.

Results

A total of 2,352 participants were analyzed. We discovered significant associations between the pregnancy zone protein locus and concentrations of ADAM-12 (rs6487735, P= 3.03×10 -22 ), as well as between the vascular endothelial growth factor A locus and concentrations of both VEGF (rs6921438, P= 7.94×10 -30 ) and sFlt-1 (rs4349809, P= 2.89×10 -12 ). Our Mendelian randomization analyses suggested a potential causal association between first-trimester ADAM-12 levels and gestational hypertension (odds ratio=0.78, P= 8.6×10 -4 ). We also found evidence for a potential causal effect of preeclampsia (odds ratio=1.75, P =8.3×10 -3 ) and gestational hypertension (odds ratio=1.84, P =4.7×10 -3 ) during the index pregnancy on the onset of hypertension 2-7 years later. The additional mediation analysis indicated that the impact of ADAM-12 on postpartum hypertension could be explained in part by its indirect effect through gestational hypertension (mediated effect=-0.15, P= 0.03).

Conclusions

Our study discovered significant genetic associations with placental proteins ADAM-12, VEGF, and sFlt-1, offering insights into their regulation during pregnancy. Mendelian randomization analyses demonstrated evidence of potential causal relationships between the serum levels of placental proteins, particularly ADAM-12, and gestational hypertension, potentially informing future prevention and treatment investigations.

Common variation in a long non-coding RNA gene modulates variation of circulating TGF-β2 levels in metastatic colorectal cancer patients (Alliance)

BACKGROUND

Herein, we report results from a genome-wide study conducted to identify protein quantitative trait loci (pQTL) for circulating angiogenic and inflammatory protein markers in patients with metastatic colorectal cancer (mCRC). The study was conducted using genotype, protein marker, and baseline clinical and demographic data from CALGB/SWOG 80405 (Alliance), a randomized phase III study designed to assess outcomes of adding VEGF or EGFR inhibitors to systemic chemotherapy in mCRC patients. Germline DNA derived from blood was genotyped on whole-genome array platforms. The abundance of protein markers was quantified using a multiplex enzyme-linked immunosorbent assay from plasma derived from peripheral venous blood collected at baseline. A robust rank-based method was used to assess the statistical significance of each variant and protein pair against a strict genome-wide level. A given pQTL was tested for validation in two external datasets of prostate (CALGB 90401) and pancreatic cancer (CALGB 80303) patients. Bioinformatics analyses were conducted to further establish biological bases for these findings.

RESULTS

The final analysis was carried out based on data from 540,021 common typed genetic variants and 23 protein markers from 869 genetically estimated European patients with mCRC. Correcting for multiple testing, the analysis discovered a novel cis-pQTL in LINC02869, a long non-coding RNA gene, for circulating TGF-β2 levels (rs11118119; AAF = 0.11; P-value < 1.4e-14). This finding was validated in a cohort of 538 prostate cancer patients from CALGB 90401 (AAF = 0.10, P-value < 3.3e-25). The analysis also validated a cis-pQTL we had previously reported for VEGF-A in advanced pancreatic cancer, and additionally identified trans-pQTLs for VEGF-R3, and cis-pQTLs for CD73.

CONCLUSIONS

This study has provided evidence of a novel cis germline genetic variant that regulates circulating TGF-β2 levels in plasma of patients with advanced mCRC and prostate cancer. Moreover, the validation of previously identified pQTLs for VEGF-A, CD73, and VEGF-R3, potentiates the validity of these associations.

Proteomic insights into modifiable risk of venous thromboembolism and cardiovascular comorbidities

BACKGROUND

Venous thromboembolism (VTE) has been associated with several modifiable factors (MFs) and cardiovascular comorbidities. However, the mechanisms are largely unknown.

OBJECTIVES

We aimed to decipher proteomic pathways underlying the associations of VTE with MFs and cardiovascular comorbidities.

METHODS

A 2-stage network Mendelian randomization analysis was conducted to explore the associations between 15 MFs, 1151 blood proteins, and VTE using data from a genome-wide meta-analysis including 81 190 cases of VTE. We used protein data from 35 559 individuals as the discovery analysis, and from 2 independent studies including 10 708 and 54 219 participants as the replication analyses. Based on the identified proteins, we assessed the druggability and examined the cardiovascular pleiotropy.

RESULTS

The network Mendelian randomization analyses identified 10 MF-VTE, 86 MF-protein, and 34 protein-VTE associations. These associations were overall consistent in the replication analyses. Thirty-eight pathways with directionally consistent direct and indirect effects in the MF-protein-VTE pathway were identified. Low-density lipoprotein receptor-related protein 12 (LRP12: 34.3%-58.1%) and coagulation factor (F)XI (20.6%-39.6%) mediated most of the associations between 3 obesity indicators and VTE. Likewise, coagulation FXI mediated most of the smoking-VTE association (40%; 95% CI, 20%-60%) and insomnia-VTE association (27%; 95% CI, 5%-49%). Many VTE-associated proteins were highly druggable for thrombotic conditions. Five proteins (interleukin-6 receptor subunit alpha, LRP12, prothrombin, angiopoietin-1, and low-density lipoprotein receptor-related protein 4) were associated with VTE and its cardiovascular comorbidities.

CONCLUSION

This study suggests that coagulation FXI, a druggable target, is an important mediator of the associations of obesity, smoking, and insomnia with VTE risk.

Common variation in a long non-coding RNA gene modulates variation of circulating TGF-β2 levels in metastatic colorectal cancer patients (Alliance)

Background

Herein, we report results from a genome-wide study conducted to identify protein quantitative trait loci (pQTL) for circulating angiogenic and inflammatory protein markers in patients with metastatic colorectal cancer (mCRC).The study was conducted using genotype, protein marker, and baseline clinical and demographic data from CALGB/SWOG 80405 (Alliance), a randomized phase III study designed to assess outcomes of adding VEGF or EGFR inhibitors to systemic chemotherapy in mCRC patients. Germline DNA derived from blood was genotyped on whole-genome array platforms. The abundance of protein markers was quantified using a multiplex enzyme-linked immunosorbent assay from plasma derived from peripheral venous blood collected at baseline. A robust rank-based method was used to assess the statistical significance of each variant and protein pair against a strict genome-wide level. A given pQTL was tested for validation in two external datasets of prostate (CALGB 90401) and pancreatic cancer (CALGB 80303) patients. Bioinformatics analyses were conducted to further establish biological bases for these findings.

Results

The final analysis was carried out based on data from 540,021 common typed genetic variants and 23 protein markers from 869 genetically estimated European patients with mCRC. Correcting for multiple testing, the analysis discovered a novel cis-pQTL in LINC02869, a long non-coding RNA gene, for circulating TGF-β2 levels (rs11118119; AAF = 0.11; P-value < 1.4e-14). This finding was validated in a cohort of 538 prostate cancer patients from CALGB 90401 (AAF = 0.10, P-value < 3.3e-25). The analysis also validated a cis-pQTL we had previously reported for VEGF-A in advanced pancreatic cancer, and additionally identified trans-pQTLs for VEGF-R3, and cis-pQTLs for CD73.

Conclusions

This study has provided evidence of a novel cis germline genetic variant that regulates circulating TGF-β2 levels in plasma of patients with advanced mCRC and prostate cancer. Moreover, the validation of previously identified pQTLs for VEGF-A, CD73, and VEGF-R3, potentiates the validity of these associations.

Venous thromboembolism-related genetic determinant F11 rs4253417 is a potential prognostic factor in ischaemic stroke

Ischaemic stroke (IS) and venous thromboembolism (VTE) are two forms of thromboembolism that, although distinct, seem to share numerous risk factors. Concerning genetic risk factors, while many VTE genetic markers have been reported, inclusively by genome-wide association studies (GWAS), the identification and validation of genetic determinants underlying IS pathogenesis have been challenging. Considering that IS and VTE shared biological pathways and aetiological factors, the severity of IS might be also influenced by VTE-related genetic variants. Thus, the present study was designed to analyse the impact of six VTE GWAS-identified genetic variants on the clinical outcome of 363 acute IS patients. Results revealed that the single-nucleotide polymorphism (SNP) F11 rs4253417 was an independent predictor of the 5-year risk of death among patients with total anterior circulation infarct (TACI). Namely, the ones carrying the SNP C allele presented a fourfold increase in the 5-year risk of death compared to TT genotype carriers (CC/CT vs. TT; adjusted HR, 4.240; 95% CI, 1.260-14.270; P = 0.020). This SNP is known to be associated with coagulation factor XI (FXI) levels, thus with implications in haemostasis and inflammation. As such, F11 rs4253417 might be a promising prognostic biomarker among TACI patients to aid in clinical decision-making. However, additional investigation is required to confirm the study's results and dissect the underlying mechanisms.

Thrombogenesis-associated genetic determinants as predictors of thromboembolism and prognosis in cervical cancer

Venous thromboembolism (VTE) is a leading cause of death among cancer patients. Khorana score (KS) is the most studied tool to predict cancer-related VTE, however, it exerts poor sensitivity. Several single-nucleotide polymorphisms (SNPs) have been associated with VTE risk in the general population, but whether they are predictors of cancer-related VTE is a matter of discussion. Compared to other solid tumours, little is known about VTE in the setting of cervical cancer (CC) and whether thrombogenesis-related polymorphisms could be valuable biomarkers in patients with this neoplasia. This study aims to analyse the effect of VTE occurrence on the prognosis of CC patients, explore the predictive capability of KS and the impact of thrombogenesis-related polymorphisms on CC-related VTE incidence and patients' prognosis regardless of VTE. A profile of eight SNPs was evaluated. A retrospective hospital-based cohort study was conducted with 400 CC patients under chemoradiotherapy. SNP genotyping was carried on by using TaqMan® Allelic Discrimination methodology. Time to VTE occurrence and overall survival were the two measures of clinical outcome evaluated. The results indicated that VTE occurrence (8.5%) had a significant impact on the patient's survival (log-rank test, P < 0.001). KS showed poor performance (KS ≥ 3, χ², P = 0.191). PROCR rs10747514 and RGS7 rs2502448 were significantly associated with the risk of CC-related VTE development (P = 0.021 and P = 0.006, respectively) and represented valuable prognostic biomarkers regardless of VTE (P = 0.004 and P = 0.010, respectively). Thus, thrombogenesis-related genetic polymorphisms may constitute valuable biomarkers among CC patients allowing a more personalized clinical intervention.

VEGF-A related SNPs: a cardiovascular context

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Currently, cardiovascular disease risk algorithms play a role in primary prevention. However, this is complicated by a lack of powerfully predictive biomarkers that could be observed in individuals before the onset of overt symptoms. A key potential biomarker for heart disease is the vascular endothelial growth factor (VEGF-A), a molecule that plays a pivotal role in blood vessel formation. This molecule has a complex biological role in the cardiovascular system due to the processes it influences, and its production is impacted by various CVD risk factors. Research in different populations has shown single nucleotide polymorphisms (SNPs) may affect circulating VEGF-A plasma levels, with some variants associated with the development of CVDs, as well as CVD risk factors. This minireview aims to give an overview of the VEGF family, and of the SNPs reported to influence VEGF-A levels, cardiovascular disease, and other risk factors used in CVD risk assessments.

Associations of VEGF-A-Related Variants with Adolescent Cardiometabolic and Dietary Parameters

Previous research has allowed the identification of variants related to the vascular endothelial growth factor-A (VEGF-A) and their association with anthropometric, lipidemic and glycemic indices. The present study examined potential relations between key VEGF-A-related single-nucleotide polymorphisms (SNPs), cardiometabolic parameters and dietary habits in an adolescent cohort. Cross-sectional analyses were conducted using baseline data from 766 participants of the Greek TEENAGE study. Eleven VEGF-A-related SNPs were examined for associations with cardiometabolic indices through multivariate linear regressions after adjusting for confounding factors. A 9-SNP unweighted genetic risk score (uGRS) for increased VEGF-A levels was constructed to examine associations and the effect of its interactions with previously extracted dietary patterns for the cohort. Two variants (rs4416670, rs7043199) displayed significant associations (p-values < 0.005) with the logarithms of systolic and diastolic blood pressure (logSBP and logDBP). The uGRS was significantly associated with higher values of the logarithm of Body Mass Index (logBMI) and logSBP (p-values < 0.05). Interactions between the uGRS and specific dietary patterns were related to higher logDBP and logGlucose (p-values < 0.01). The present analyses constitute the first-ever attempt to investigate the influence of VEGF-A-related variants on teenage cardiometabolic determinants, unveiling several associations and the modifying effect of diet.

Germline genetic variation and predicting immune checkpoint inhibitor induced toxicity

Immune checkpoint inhibitor (ICI) therapy has revolutionised the treatment of various cancer types. ICIs reinstate T-cell function to elicit an anti-cancer immune response. The resulting immune response can however have off-target effects which manifest as autoimmune type serious immune-related adverse events (irAE) in ~10-55% of patients treated. It is currently challenging to predict both who will experience irAEs and to what severity. Identification of patients at high risk of serious irAE would revolutionise patient care. While the pathogenesis driving irAE development is still unclear, host genetic factors are proposed to be key determinants of these events. This review presents current evidence supporting the role of the host genome in determining risk of irAE. We summarise the spectrum and timing of irAEs following treatment with ICIs and describe currently reported germline genetic variation associated with expression of immuno-modulatory factors within the cancer immunity cycle, development of autoimmune disease and irAE occurrence. We propose that germline genetic determinants of host immune function and autoimmune diseases could also explain risk of irAE development. We also endorse genome-wide association studies of patients being treated with ICIs to identify genetic variants that can be used in polygenic risk scores to predict risk of irAE.

The Association between Single Nucleotide Polymorphisms, including miR-499a Genetic Variants, and Dyslipidemia in Subjects Treated with Pharmacological or Phytochemical Lipid-Lowering Agents

Disorders of lipoprotein metabolism are among the major risk factors for cardiovascular disease (CVD) development. Single nucleotide polymorphisms (SNPs) have been associated with the individual variability in blood lipid profile and response to lipid-lowering treatments. Here, we genotyped 34 selected SNPs located in coding genes related to lipid metabolism, inflammation, coagulation, and a polymorphism in the MIR499 gene—a microRNA previously linked to CVD—to evaluate the association with lipid trait in subjects with moderate dyslipidemia not on lipid-lowering treatment (Treatment-naïve (TN) cohort, n = 125) and in patients treated with statins (STAT cohort, n = 302). We also explored the association between SNPs and the effect of a novel phytochemical lipid-lowering treatment in the TN cohort. We found that 6 SNPs (in the MIR499, TNFA, CETP, SOD2, and VEGFA genes) were associated with lipid traits in the TN cohort, while no association was found with the response to twelve-week phytochemical treatment. In the STAT cohort, nine SNPs (in the MIR499, CETP, CYP2C9, IL6, ABCC2, PON1, IL10, and VEGFA genes) were associated with lipid traits, three of which were in common with the TN cohort. Interestingly, in both cohorts, the presence of the rs3746444 MIR499 SNP was associated with a more favorable blood lipid profile. Our findings could add information to better understand the individual genetic variability in maintaining a low atherogenic lipid profile and the response to different lipid-lowering therapies.

VEGF-A-related genetic variants protect against Alzheimer's disease

The Apolipoprotein E (APOE) genotype has been shown to be the strongest genetic risk factor for Alzheimer’s disease (AD). Moreover, both the lipolysis-stimulated lipoprotein receptor (LSR) and the vascular endothelial growth factor A (VEGF-A) are involved in the development of AD. The aim of the study was to develop a prediction model for AD including single nucleotide polymorphisms (SNP) of APOE, LSR and VEGF-A-related variants.

The population consisted of 323 individuals (143 AD cases and 180 controls). Genotyping was performed for: the APOE common polymorphism (rs429358 and rs7412), two LSR variants (rs34259399 and rs916147) and 10 VEGF-A-related SNPs (rs6921438, rs7043199, rs6993770, rs2375981, rs34528081, rs4782371, rs2639990, rs10761741, rs114694170, rs1740073), previously identified as genetic determinants of VEGF-A levels in GWAS studies. The prediction model included direct and epistatic interaction effects, age and sex and was developed using the elastic net machine learning methodology.

An optimal model including the direct effect of the APOE e4 allele, age and eight epistatic interactions between APOE and LSR, APOE and VEGF-A-related variants was developed with an accuracy of 72%. Two epistatic interactions (rs7043199*rs6993770 and rs2375981*rs34528081) were the strongest protective factors against AD together with the absence of ε4 APOE allele. Based on pathway analysis, the involved variants and related genes are implicated in neurological diseases.

In conclusion, this study demonstrated links between APOE, LSR and VEGF-A-related variants and the development of AD and proposed a model of nine genetic variants which appears to strongly influence the risk for AD.

Genetic Regulation of Cytokine Response in Patients with Acute Community-Acquired Pneumonia

Background: Community-acquired pneumonia (CAP) is an acute disease condition with a high risk of rapid deteriorations. We analysed the influence of genetics on cytokine regulation to obtain a better understanding of patient’s heterogeneity. Methods: For up to N = 389 genotyped participants of the PROGRESS study of hospitalised CAP patients, we performed a genome-wide association study of ten cytokines IL-1β, IL-6, IL-8, IL-10, IL-12, MCP-1 (MCAF), MIP-1α (CCL3), VEGF, VCAM-1, and ICAM-1. Consecutive secondary analyses were performed to identify independent hits and corresponding causal variants. Results: 102 SNPs from 14 loci showed genome-wide significant associations with five of the cytokines. The most interesting associations were found at 6p21.1 for VEGF (p = 1.58 × 10⁻²⁰), at 17q21.32 (p = 1.51 × 10⁻⁹) and at 10p12.1 (p = 2.76 × 10⁻⁹) for IL-1β, at 10p13 for MIP-1α (CCL3) (p = 2.28 × 10⁻⁹), and at 9q34.12 for IL-10 (p = 4.52 × 10⁻⁸). Functionally plausible genes could be assigned to the majority of loci including genes involved in cytokine secretion, granulocyte function, and cilial kinetics. Conclusion: This is the first context-specific genetic association study of blood cytokine concentrations in CAP patients revealing numerous biologically plausible candidate genes. Two of the loci were also associated with atherosclerosis with probable common or consecutive pathomechanisms.

A genetic determinant of VEGF-A levels is associated with telomere attrition

Telomere length (TL) is a hallmark of cellular aging and is associated with chronic diseases development. The vascular endothelial growth factor A (VEGF-A), a potent angiogenesis factor, is implicated in the pathophysiology of many chronic diseases. The aim of the present study was to investigate the associations between VEGF-A and TL.

TL in leukocytes (LTL) and skeletal muscle (MTL) were measured, 10 VEGF-related polymorphisms genotyped, and VEGF-A plasma concentrations determined in 402 individuals from the TELARTA cohort. LTL/MTL ratio was calculated as an estimate of lifelong TL attrition. Associations between VEGF-A variants and levels, and TL parameters were investigated.

We identified one significant association between the minor allele (T) of rs6993770 variant and LTL/MTL ratio (P=0.001143, β=0.0148, SE=0.004516). The rs6993770 is an intronic variant of the ZFPM2 gene, which is involved in haematopoiesis and the identified association with increased telomere attrition could be due to increased haematopoiesis. No significant epistatic interaction was identified, and no association was found between levels of VEGF-A and any of assessed phenotypes.

We identified a potential common genetic regulation between VEGF-A and telomere length attrition that could be explained by mechanisms of increased hematopoiesis and production of platelets. VEGF-A and TL could play an important role in personalized medicine of chronic diseases and identification of molecular links between them can promote the understanding of their complex implications.

Comparative effects of on-pump versus off-pump coronary artery bypass grafting surgery on serum cytokine and chemokine levels

Coronary artery bypass grafting (CABG) surgery with two methods (on-pump or off-pump) can be used to rescue individuals with severe coronary artery disease (CAD). Each method might cause an inflammatory response, which can lead to some complications. The aim of this study was to compare the changes in serum concentrations of IFN-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, VEGF, MCP-1, and epidermal growth factor between the two CABG surgery methods. Forty-eight patients (22 = on-pump, 26 = off-pump) who underwent on-pump or off-pump CABG surgery were enrolled in this study. Serum cytokines levels were measured in two blood samples, the first sample was taken from each patient in the morning of the day of surgery after a 12-hr fasting and the second sample on the first postoperative day at 24-hr after surgery. In baseline, comparisons between the two groups of on-pump/off-pump surgery did not show any significant difference in demographic data, anthropometric parameters, lipid profile indices, and high-sensitivity C-reactive protein levels (p > .05). There was a significant difference between the serum levels of IL-4, IL-6, IL-10, vascular endothelial growth factor (VEGF), IFN-γ, and MCP-1 in patients with on-pump surgery and a significant increase in serum IL-6 (p < .001), IL8 (p < .05), VEGF (p < .001), and IFN-γ (p < .01) levels in patients with off-pump surgery in post-operation stage compared to pre-operation. Cardiopulmonary pump in patients under CABG surgery can activate systemic inflammation and the changes of serum cytokines levels in off-pump CABG were lower compared with on-pump CABG.

Quantile-specific heritability of serum growth factor concentrations

BACKGROUND

"Quantile-dependent expressivity" occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g. growth factor concentration) is high or low relative to its distribution.

METHODS

Quantile-regression analysis was applied to family sets from the Framingham Heart Study to determine whether the heritability (h²) of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), angiopoietin-2, and angiopoietin-2 (sTie-2) and VEGFR1 (sFlt-1) receptor concentrations were quantile-specific.

RESULTS

Quantile-specific h² (±SE) increased with increasing percentiles of the age- and sex-adjusted VEGF (P_trend<10^-16), HGF (P_trend=0.0004), angiopoietin-2 (P_trend=0.0002), sTie-2 (P_trend=1.2 × 10^-5), and sFlt-1 distributions (P_trend=0.04).

CONCLUSION

Heritabilities of VEGF, HGF, angiopoitein-2, sTie-2 and sFlt-1 concentrations are quantile dependent. This may explain reported interactions of genetic loci (rs10738760, rs9472159, rs833061, rs3025039, rs2280789, rs1570360, rs2010963) with metabolic syndrome, diet, recurrent miscarriage, hepatocellular carcinoma, erysipelas, diabetic retinopathy, and bevacizumab treatment in their effect on VEGF concentrations.

Immune and Inflammatory Pathways Implicated by Whole Blood Transcriptomic Analysis in a Diverse Ancestry Alzheimer's Disease Cohort

BACKGROUND

Significant work has identified genetic variants conferring risk and protection for Alzheimer's disease (AD), but functional effects of these variants is lacking, particularly in under-represented ancestral populations. Expression studies performed in easily accessible tissue, such as whole blood, can recapitulate some transcriptional changes occurring in brain and help to identify mechanisms underlying neurodegenerative processes.

OBJECTIVE

We aimed to identify transcriptional differences between AD cases and controls in a cohort of diverse ancestry.

METHODS

We analyzed the protein coding transcriptome using RNA sequencing from peripheral blood collected from 234 African American (AA) (115 AD, 119 controls) and 240 non-Hispanic Whites (NHW) (121 AD, 119 controls). To identify case-control differentially expressed genes and pathways, we performed stratified, joint, and interaction analyses using linear regression models within and across ancestral groups followed by pathway and gene set enrichment analyses.

RESULTS

Overall, we identified 418 (291 upregulated, 127 downregulated) and 488 genes (352 upregulated, 136 downregulated) differentially expressed in the AA and NHW datasets, respectively, with only 16 genes commonly differentially expressed in both ancestral groups. Joint analyses provided greater power to detect case-control differences and identified 1,102 differentially expressed genes between cases and controls (812 upregulated, 290 downregulated). Interaction analysis identified only 27 genes with different effects in AA compared to NHW. Pathway and gene-set enrichment analyses revealed differences in immune response-related pathways that were enriched across the analyses despite different underlying gene sets.

CONCLUSION

These results support the hypothesis of converging underlying pathophysiological processes in AD across ancestral groups.

Epigenome-wide association study in healthy individuals identifies significant associations with DNA methylation and PBMC extract VEGF-A concentration

Introduction

Vascular endothelial growth factor A (VEGF-A) is a chemokine that induces proliferation and migration of vascular endothelial cells and is essential for both physiological and pathological angiogenesis. It is known for its high heritability (> 60%) and involvement in most common morbidities, which makes it a potentially interesting biomarker. Large GWAS studies have already assessed polymorphisms related to VEGF-A. However, no previous research has provided epigenome-wide insight in regulation of VEGF-A.

Methods

VEGF-A concentrations of healthy participants from the STANISLAS Family Study (n = 201) were comprehensively assessed for association with DNA methylation. Genome-wide DNA methylation profiles were determined in whole blood DNA using the 450K Infinium BeadChip Array (Illumina). VEGF-A concentration in PBMC extracts was detected using a high-sensitivity multiplex Cytokine Array (Randox Laboratories, UK).

Results

Epigenome-wide association analysis identified 41 methylation sites significantly associated with VEGF-A concentrations derived from PBMC extracts. Twenty CpG sites within 13 chromosomes reached Holm-Bonferroni significance. Significant values ranged from P = 1.08 × 10⁻⁷ to P = 5.64 × 10⁻¹⁵.

Conclusion

This study exposed twenty significant CpG sites linking DNA methylation to VEGF-A concentration. Methylation detected in promoter regions, such as TPX2 and HAS-1, could explain previously reported associations with the VEGFA gene. Methylation may also help in the understanding of the regulatory mechanisms of other genes located in the vicinity of detected CpG sites.

Multivariate Genome-wide Association Analysis of a Cytokine Network Reveals Variants with Widespread Immune, Haematological, and Cardiometabolic Pleiotropy

Cytokines are essential regulatory components of the immune system, and their aberrant levels have been linked to many disease states. Despite increasing evidence that cytokines operate in concert, many of the physiological interactions between cytokines, and the shared genetic architecture that underlies them, remain unknown. Here, we aimed to identify and characterize genetic variants with pleiotropic effects on cytokines. Using three population-based cohorts (n = 9,263), we performed multivariate genome-wide association studies (GWAS) for a correlation network of 11 circulating cytokines, then combined our results in meta-analysis. We identified a total of eight loci significantly associated with the cytokine network, of which two (PDGFRB and ABO) had not been detected previously. In addition, conditional analyses revealed a further four secondary signals at three known cytokine loci. Integration, through the use of Bayesian colocalization analysis, of publicly available GWAS summary statistics with the cytokine network associations revealed shared causal variants between the eight cytokine loci and other traits; in particular, cytokine network variants at the ABO, SERPINE2, and ZFPM2 loci showed pleiotropic effects on the production of immune-related proteins, on metabolic traits such as lipoprotein and lipid levels, on blood-cell-related traits such as platelet count, and on disease traits such as coronary artery disease and type 2 diabetes.

Relationship between VEGF-related gene polymorphisms and brain morphology in treatment-naïve patients with first-episode major depressive disorder

Vascular endothelial growth factor (VEGF) is involved in the development of major depressive disorder (MDD). Recently, a genome-wide association study has revealed that four VEGF-related single nucleotide polymorphisms (SNPs) (i.e., rs4416670, rs6921438, rs6993770 and rs10738760) were independently associated with circulating VEGF levels. The current study investigated the relationship between brain volume and these four SNPs in first-episode drug-naïve MDD patients. A total of 38 first-episode drug-naïve MDD patients and 39 healthy subjects (HS) were recruited and underwent high-resolution T1-weighted imaging. Blood samples were collected from all the participants for serum VEGF assays and VEGF-related SNPs genotyping. Genotype-diagnosis interactions related to whole-brain cortical thickness and hippocampal subfield volumes were evaluated for the four SNPs. The results revealed a genotype-diagnosis interaction only for rs6921438 (i.e., the MDD patients and HS with the G/G genotype versus the MDD patients and HS with A-carrier genotype) in the subiculum of the left hippocampus (p < 0.05), and not the other SNPs. There was a volume reduction in the left subiculum of G/G genotype patients compared with the other groups. The "hypochondriasis" scores of the HAMD-17 scale were significantly higher in the G/G genotype patients than the A-carrier genotype patients. The association was observed between VEGF-related SNP rs6921438 and subiculum atrophy in first-episode drug-naïve MDD patients.

Peripheral blood mononuclear cells extracts VEGF protein levels and VEGF mRNA: Associations with inflammatory molecules in a healthy population

Background

Vascular endothelial growth factor (VEGF) is a signal protein, implicated in various physiological and pathophysiological processes together with other common inflammatory biomarkers. However, their associations have not yet been fully elucidated. In the present study, we investigated associations between VEGF and four specific VEGF mRNA isoforms with levels of 11 inflammation molecules, derived from peripheral blood mononuclear cells (PBMCs) extracts.

Methods

Healthy participants from the STANISLAS Family Study (n = 285) were included. Levels of VEGF (four mRNA isoforms and protein levels) and inflammatory molecules (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, INF-γ, TNF-α, MCP-1, EGF) were measured in PBMCs extracts. Multiple regression analyses were performed, adjusted for age and gender.

Results

The analyses revealed significant associations between VEGF protein levels and levels of IL-4 (β = 0.028, P = 0.013), MCP-1 (β = 0.015, P<0.0001) and EGF (β = 0.017, P<0.0001). Furthermore, mRNA isoform VEGF₁₆₅ was associated with MCP-1 and IL-1α (P = 0.002 and P = 0.008, respectively); and mRNA isoform VEGF₁₈₉ was associated with IL-4 and IL-6 (P = 0.019 and P = 0.034, respectively).

Conclusions

To our knowledge, the present study represents the first investigation that successfully demonstrates links between VEGF protein levels and inflammatory molecules levels derived from PBMCs extracts and identifies associations between specific VEGF mRNA isoforms and inflammatory molecules.

Impact

These findings provide novel insights that may assist in the development of new tissue and mRNA isoform specific measurements of VEGF levels, which may positively contribute to predicting the risk of common complex diseases and response of currently used anti-VEGF agents, and developing of novel targeted therapies for VEGF-related pathophysiology.

Association between SNPs of Circulating Vascular Endothelial Growth Factor Levels, Hypercholesterolemia and Metabolic Syndrome

Background and Objectives: Four single nucleotide polymorphisms (SNPs); rs6921438 and rs4416670 in LOC100132354-C6orf223, rs6993770 in ZFPM2, and rs10738760 in VLDLR-KCNV2 were reported to explain up to 50% of the heritability of vascular endothelial growth factor circulating levels. These SNPs were also studied for possible associations with circulating lipid levels in supposedly healthy European individuals and in a limited number of Iranian individuals with metabolic syndrome. To go further, the association of those four SNPs with plasma lipid parameters, hypercholesterolemia and metabolic syndrome (MetS) was assessed. Materials and Methods: A cross-sectional study was conducted on 460 individuals chosen from the general population. Demographic and clinical data were collected and DNA was extracted and genotyped using Kompetitive allele specific PCR (KASP™). A meta-analysis followed, combining our participants with the Iranian individuals (n = 336). Results: Whereas rs10738760 was associated with total cholesterol (Tchol) (p = 0.01), rs6993770 showed significant associations with both Tchol and low-density lipoprotein cholesterol (LDL-C) levels (p = 0.007 and p = 0.01 respectively). Using a multivariate logistic regression model adjusted for different confounding factors, we found that rs6993770 was associated with hypercholesterolemia, specifically high Tchol (p = 0.01) and LDL-C levels (p = 0.01). Furthermore, rs10738760 was positively associated with the risk of MetS in these individuals (p = 0.02) and in the meta-analysis (OR = 1.67, p = 0.01). Conclusion: Our results suggest that whereas rs6993770 in ZFPM2 was positively associated with hypercholesterolemia, rs10738760 (VLDLR-KCNV2) has a possible implication in MetS in two Middle Eastern populations.

Role of Neuronal VEGF Signaling in the Prefrontal Cortex in the Rapid Antidepressant Effects of Ketamine

OBJECTIVE

The N-methyl-d-aspartate receptor antagonist ketamine produces rapid and sustained antidepressant actions even in patients with treatment-resistant depression. Vascular endothelial growth factor (VEGF) has been implicated in the effects of conventional monoamine-based antidepressants, but the role of VEGF in the rapid antidepressant actions of ketamine remains unclear. The authors examined whether neuronal VEGF signaling in the medial prefrontal cortex (mPFC) mediates the rapid antidepressant actions of ketamine.

METHODS

The authors used a combination of approaches, including conditional, neuron-specific knockout of VEGF or its receptor, Flk-1; antibody neutralization; viral-mediated knockdown of Flk-1; and pharmacological inhibitors. Further in vitro and in vivo experiments were performed to examine whether neuronal VEGF signaling was required for the neurotrophic and synaptogenic actions of ketamine that underlie its behavioral actions.

RESULTS

The behavioral actions of systemic ketamine are blocked by forebrain excitatory neuron-specific deletion of either VEGF or Flk-1 or by intra-mPFC infusion of a VEGF neutralizing antibody. Moreover, intra-mPFC infusions of VEGF are sufficient to produce rapid ketamine-like behavioral actions, and these effects are blocked by neuron-specific Flk-1 deletion. The results also show that local knockdown of Flk-1 in mPFC excitatory neurons in adulthood blocks the behavioral effects of systemic ketamine. Moreover, inhibition of neuronal VEGF signaling blocks the neurotrophic and synaptogenic effects of ketamine.

CONCLUSIONS

Together, these findings indicate that neuronal VEGF-Flk-1 signaling in the mPFC plays an essential role in the antidepressant actions of ketamine.

Serum Vascular Endothelial Growth Factor in Egyptian Obese Women with Insulin Resistance

BACKGROUND:

Obesity is a major factor in the development of several sub-clinical anomalies. Insulin resistance (IR) is associated with obesity. Vascular endothelial growth factor (VEGF) plays a significant role in inflammation and vascular neogenesis. However the precise relationships of its levels with clinical, lipid, and metabolic profiles are unknown.

AIM:

This study aimed to examine the association between serum VEGF concentrations with IR risk and metabolic and lipid parameters in obese women.

METHODS:

Serum VEGF, metabolic biomarkers and anthropometry were measured in 83 obese women with IR and 50 healthy women. Fat distributions in the abdominal, subcutaneous and visceral area were assessed. Homeostasis model assessment for insulin resistance index (HOMA-IR) was calculated. For analytical purposes, VEGF levels were categorised into three tertiles groups.

RESULTS:

Obese women with IR showed significantly higher levels of serum VEGF as compared with the control group. Moreover, obese women in the highest VEGF tertile had significantly higher values of obesity indices, visceral fat index, abnormal lipid levels and HOMA-IR compared to with those in the lower tertile.

CONCLUSION:

Elevated VEGF levels are associated with IR and high visceral fat index in obese women which in turn increased the risk for metabolic complications.

Vascular endothelial growth factor (VEGF)-related polymorphisms rs10738760 and rs6921438 are not risk factors for proliferative diabetic retinopathy (PDR) in patients with type 2 diabetes mellitus (T2DM)

Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis and has been investigated as a candidate gene in a number of conditions, including diabetes and its microvascular complications (e.g., retinopathy and nephropathy). Several VEGF-related polymorphisms have been shown to contribute to nearly half of the variability in circulating VEGF levels in healthy individuals. Our aim was to assess the association between VEGF-related rs10738760 and rs6921438 polymorphisms and proliferative diabetic retinopathy (PDR) in Slovenian patients with type 2 diabetes mellitus (T2DM). We also investigated the effect of these polymorphisms on VEGF receptor 2 (VEGFR-2) expression in fibrovascular membranes (FVMs) from patients with PDR. This case-control study enrolled 505 unrelated patients with T2DM: 143 diabetic patients with PDR as a study group, and 362 patients with T2DM of >10 years duration and with no clinical signs of PDR as a control group. Patient clinical and laboratory data were obtained from their medical records. rs10738760 and rs6921438 polymorphisms were genotyped using TaqMan SNP Genotyping assay. VEGFR-2 expression was assessed by immunohistochemistry in 20 FVMs from patients with PDR, and numerical areal density of VEGFR-2-positive cells was calculated. The occurrence of PDR was 1.7 times higher in diabetic patients carrying GA genotype of rs6921438 compared to patients with GG genotype, with a borderline statistical significance (OR = 1.7, 95% CI = 1.00 - 2.86, p = 0.05). In addition, A allele of rs6921438 was associated with increased VEGFR-2 expression in FVMs from PDR patients. However, we observed no association between AA genotype of rs6921438 nor between rs10738760 variants and PDR, indicating that the two polymorphisms are not genetic risk factors for PDR.

VEGF gene polymorphism interactions with dietary trace elements intake in determining the risk of metabolic syndrome

There is a complex association among genetic, metabolic, and environmental factors in determining the risk of metabolic syndrome (MetS). The aim of this study was to investigate the role of the association between the dietary intake of iron, copper, zinc, manganese, selenium, and iodine (assessed by 24 recall) with vascular endothelial growth factor variants (rs6921438, rs4416670, rs6993770, and rs10738760), on the risk of MetS. Two-hundred and forty-eight individuals with MetS and 100 individuals without MetS were recruited. The dietary intake and the daily average of energy and nutrient intake were obtained by a questionnaire and quantified using Diet Plan 6 software. DNA was extracted from EDTA anticoagulated whole blood. The SNPs were assessed using using a Sequenom iPLEX Gold assay. Data analysis was undertaken using the Student t test, χ2 test and logistic regression using SPSS 11.5 software. There was a significant association between low dietary iron intake and rs6993770 (β = .10, P < .05), and a low dietary zinc and a high manganese intake with rs6921438 in relation to the presence of MetS (β = -.17, P < .05, β = -.30, P < .05, respectively). Our data showed the association of rs6993770 with iron intake and rs6921438 with zinc and manganese intake, indicating further investigation in a larger population to evaluate their values.

Genetic variation determines VEGF-A plasma levels in cancer patients

Angiogenesis is essential in tumor biology and is regulated by vascular endothelial growth factor (VEGF) ligands and receptors. Here we aimed to discover genetic variants associated with levels of circulating angiogenic proteins in cancer patients. Plasma was collected at baseline in 216 pancreatic and 114 colorectal cancer patients. Thirty-one angiogenic proteins were measured by ELISA. 484,523 Single Nucleotide Polymorphisms (SNP) were tested for association with plasma levels for each protein in pancreatic cancer patients. Three top-ranked hits were then genotyped in colorectal cancer patients, where associations with the same proteins were measured. The results demonstrated rs2284284 and MCP1 (P-value = 6.7e–08), rs7504372 and VEGF-C (P-value = 9.8e–09), and rs7767396 and VEGF-A (P-value = 5.8e–09) were SNP-protein pairs identified in pancreatic cancer patients. In colorectal cancer patients, only rs7767396 (A > G) and VEGF-A was validated (P-value = 5.18e–05). The AA genotype of rs7767396 exhibited 2.04–2.3 and 2.7–3.4-fold higher VEGF-A levels than those with AG and GG genotypes. The G allele of rs7767396 reduces binding of the NF-AT1 transcription factor. In conclusion, a common genetic variant predicts the plasma levels of VEGF-A in cancer patients through altered binding of NF-AT1.

Genome-wide meta-analyses identifies novel taxane-induced peripheral neuropathy-associated loci

OBJECTIVE

Taxane containing chemotherapy extends survival for breast cancer patients. However, taxane-induced peripheral neuropathy (TIPN) cannot be predicted, prevented or effectively treated. Using genome-wide analyses, we sought to identify common risk variants for TIPN.

PATIENTS AND METHODS

Women with high-risk breast cancer enrolled in SWOG 0221 were genotyped using the Illumina 1M chip. Genome-wide analyses were performed in relation to ≥grade 3 Common Terminology Criteria for Adverse Events (CTCAE) neuropathy in European and African Americans. Data were meta-analyzed with GW associations of CTCAE ≥grade 3 versus <grade 3 in CALGB 40101 assuming a fixed effects model.

RESULTS

The percentage of ≥grade 3 TIPN in 1269 European Americans and 139 African Americans in S0221, was 11.6 and 22.3%, respectively. CALGB 40101 ≥grade 3 TOPN was 7.2%. The most significant association with ≥grade 3 TIPN was the G allele of rs1858826 in GNGT1 (Pmeta=1.1×10), which showed a decrease in risk of ≥grade 3 TIPN (odds ratio=0.29, 95% confidence interval: 0.18-0.46).

CONCLUSION

The genetic variants associated with ≥grade 3 TIPN are hypothesized to have biochemical functions and reside in and near genes involved in diabetes and diabetic neuropathy. This finding is consistent with results from CALGB 40101 pathway analyses. Larger homogeneous trials with similar dosing and criteria for defining neuropathy are needed to properly assess the relationship of genomics with the neuropathy spectrum.

The Relationship Between Vascular Endothelial Growth Factor Cis- and Trans-Acting Genetic Variants and Metabolic Syndrome

BACKGROUND

We have investigated the association between 4 cis- and trans-genetic variants (rs6921438, rs4416670, rs6993770 and rs10738760) of the vascular endothelial growth factor (VEGF) gene and metabolic syndrome (MetS) and its individual components in an Iranian population.

MATERIAL & METHOD

Three hundred and thirty-six subjects were enrolled and MetS was defined according to the International-Diabetes-Federation (IDF) criteria. Genotyping was carried out in all the individuals for 4 VEGF genetic variants using an assay based on a combination of multiplex polymerase chain reaction and biochip array hybridization.

RESULTS

As may be expected, patients with MetS had significantly higher levels of serum high-sensitivity C-reactive protein, waist circumference, hip circumference, body mass index, fat percentage, systolic blood pressure, diastolic blood pressure and triglyceride, whereas the high-density lipoprotein cholesterol levels were significantly lower, compared to the control group (P < 0.05). We also found that 1 of the VEGF- level associated genetic variants, rs6993770, was associated with the presence of MetS; the less common T allele at this locus was associated with an increased risk for MetS. This association remained significant after adjustment for confounding factors (P = 0.007). Individuals with MetS carrying the AT + TT genotypes had markedly higher levels of fasting blood glucose, triglyceride and systolic blood pressure (P < 0.05).

CONCLUSIONS

We have found an association between the rs6993770 polymorphism and MetS. This gene variant was also associated with serum VEGF concentrations. There was also an association between this variant and the individual components of the MetS, including triglyceride, fasting blood glucose and systolic blood pressure.

VEGF and GLUT1 are highly heritable, inversely correlated and affected by dietary fat intake: Consequences for cognitive function in humans

Objective

Reduction of brain glucose transporter GLUT1 results in severe neurological dysfunction. VEGF is required to restore and maintain brain glucose uptake across the blood brain barrier via GLUT1, which was shown to be acutely diminished in response to a high fat diet (HFD) in mice. The genetic and HFD-related regulation and association of VEGF and GLUT1 (SLC2A1) in humans was investigated in the NUtriGenomic Analysis in Twins (NUGAT) study.

Methods

92 healthy and non-obese twins were standardized to a high-carbohydrate low-fat diet for 6 weeks before switched to a 6-week HFD under isocaloric conditions. Three clinical investigation days were conducted: after 6 weeks of low-fat diet and after 1 and 6 weeks of HFD. Serum VEGF and other cytokine levels were measured using ELISA. Gene expression in subcutaneous adipose tissue was assessed by quantitative Real-Time PCR. Genotyping was performed using microarray. The Auditory Verbal Learning Task was conducted to measure cognitive performance.

Results

In this human study, we showed that the environmental regulation of SLC2A1 expression and serum VEGF by HFD was inversely correlated and both factors showed strong heritability (>90%). In response to the HFD containing 45% fat, serum VEGF levels increased (P = 0.002) while SLC2A1 mRNA expression in adipose tissue decreased (P = 0.001). Higher BMI was additionally associated with lower SLC2A1 expression. AA-genotypes of the rs9472159 polymorphism, which explained ∼39% of the variation in circulating VEGF concentrations, showed significantly reduced serum VEGF levels (P = 6.4 × 10⁻¹¹) but higher SLC2A1 expression (P = 0.009) in adipose tissue compared to CC/CA-genotypes after 6 weeks of HFD. Memory performance in AA-genotypes declined in response to the HFD compared to CC- and CA-genotypes.

Conclusions

The results provide evidence to suggest the translatability of the dietary regulation of VEGF and GLUT1 from mouse models to humans. Our data demonstrate that HFD induces a genetically determined and correlated decrease of GLUT1 and increase of VEGF which may affect memory performance.

Clinical Trial Registration Number

NCT01631123

Angiogenesis genotyping in the selection of first-line treatment with either sunitinib or pazopanib for advanced renal cell carcinoma

Introduction

Recent data from the COMPARZ study seem to suggest a non-inferiority of pazopanib confronted with sunitinib in PFS and OS. We previously reported how VEGF and VEGFR polymorphisms might have a predictive role in patients treated with first-line sunitinib. Aim of our study was to investigate whether tumour angiogenesis genotyping could influence clinical outcome in RCC patients treated with either sunitinib or pazopanib, in order to help clinicians select the appropriate treatment for each patient.

Results

19 patients were treated with pazopanib while 78 received sunitinib. VEGF A rs833061 resulted significant in PFS in sunitinib vs pazopanib patients (CC+CT>TT in sunitinib, TT>CC+CT in pazopanib; p<0,0001); VEGF A rs2010963 resulted significant in PFS in sunitinib vs pazopanib patients (GG+CG>CC in sunitinib, CC>GG+CG in pazopanib; p<0,0001); VEGF A rs699947 resulted significant in PFS in sunitinib vs pazopanib patients (AA+AC>CC in sunitinib, CC>AA+AC in pazopanib; p<0,0001). OS showed no statistically significant difference.

Conclusions

in our analysis patients with opposite polymorphisms of rs833061, rs2010963, rs699947 of VEGF A seems to have a better PFS if treated with either sunitinib or pazopanib. Our data seem to suggest that biology could have a role choosing first line treatment for mRCC patients.

Methods

a retrospective analysis on 97 histologic samples of mRCC patients was conducted for VEGF-A, VEGF-C and VEGFR-1,2,3 single nucleotide polymorphisms (SNPs).

What is currently known about the genetics of venous thromboembolism at the dawn of next generation sequencing technologies

Venous thromboembolism (VTE) has a strong genetic component. This review summarizes what is known at the seventeen genes that are now well established to harbour VTE-associated genetic variants. In addition, it discusses additional candidate genes that deserve further validation before being claimed as VTE associated genes. Finally, several research strategies are briefly described to identify other molecular determinants of the disease.

Biventricular differences in β-adrenergic receptor signaling following burn injury

Burn injury detrimentally affects the myocardium, primarily due to over-activation of β-adrenergic receptors (β-AR). Autopsy reports from our institution reveal that patients often suffer from right ventricle (RV) failure. Since burn injury affects β-AR signaling in the left ventricle (LV), we proposed that β-AR signaling may also be altered in the RV. A rodent model with a scald burn of 60% of the total body surface area was used to test this hypothesis. Ventricles were isolated 7 days post-burn. We examined the expression of β-ARs via Western blotting and the mRNA expression of downstream signaling proteins via qRT-PCR. Cyclic adenosine monophosphate (cAMP) production and protein kinase A (PKA) activity were measured in membrane and cytosolic fractions, respectively, using enzyme immunoassay kits. β₁-AR protein expression was significantly increased in the RV following burn injury compared to non-burned RV but not in the LV (p = 0.0022). In contrast, β₂-AR expression was unaltered among the groups while G_αi expression was significantly higher in the LV post-burn (p = 0.023). B-arrestin-1 and G-protein coupled receptor kinase-2 mRNA expression were significantly increased in the left ventricle post-burn (p = 0.001, p<0.0001, respectively). cAMP production and PKA activity were significantly lower in the LV post-burn (p = 0.0063, 0.0042, respectively). These data indicate that burn injury affects the β-AR signaling pathway in the RV independently of the LV. Additionally, non-canonical β-AR signaling may be activated in the RV as cAMP production and PKA activity were unchanged despite changes in β₁-AR protein expression.

Vascular endothelial growth factor (VEGF)-related single nucleotide polymorphisms rs10738760 and rs6921438 are not associated with diabetic retinopathy (DR) in Slovenian patients with type 2 diabetes mellitus (T2DM)

Diabetic retinopathy (DR) is a complication of diabetes characterized by vascular permeability, increased tissue ischemia, and angiogenesis. One of the most important proteins involved in angiogenesis is vascular endothelial growth factor (VEGF, also known as VEGFA). A previous study demonstrated that two single nucleotide polymorphisms (SNPs), rs6921438 and rs10738760, account for nearly half the variation in circulating VEGF levels. The aim of our study was to assess the association between rs6921438 and rs10738760 and DR in Slovenian patients with type 2 diabetes mellitus (T2DM). This case-control study enrolled 1037 unrelated Slovenian individuals (Caucasians) with T2DM. DR group included 415 T2DM patients with DR, while control group included 622 T2DM patients with no clinical signs of DR. The clinical and laboratory data were obtained from the medical records of the patients. The genotyping of rs6921438 and rs10738760 SNPs was carried out with real-time PCR assays. Significant differences were observed between patients with DR and controls in the duration of diabetes (p < 0.001), insulin therapy (p < 0.001), glycated hemoglobin (p = 0.001), body mass index (p = 0.002), total cholesterol (p = 0.002), and low-density lipoprotein cholesterol (p < 0.001). However, we did not observe significant differences in the genotype and allele distribution of the two SNPs, between DR and control group (p < 0.05). Logistic regression analysis showed that rs6921438 and rs10738760 were not independent genetic risk factors for DR in the co-dominant model adjusted for the above-mentioned clinical and laboratory data. In conclusion, VEGF-related SNPs rs10738760 and rs6921438 are not associated with DR in our group of Slovenian patients (Caucasians) with T2DM.

VEGF-A gene polymorphisms and responses to intravitreal ranibizumab treatment in patients with diabetic macular edema

PURPOSE

To investigate the association between VEGF gene polymorphisms and the responses to treatment with intravitreal ranibizumab (IVR) in patients with diabetic macular edema (DME).

METHODS

This prospective study, conducted at the Kutahya Dumlupinar University Faculty of Medicine, included 95 patients with DME that were treated with IVR and 32 patients without DME despite proliferative diabetic retinopathy (PDR). The participants were divided into three groups: DME with non-proliferative diabetic retinopathy, DME with PDR, and PDR without DME; patients with DME who were treated with IVR were further divided into two groups based on their response to the treatment. Each patient was genotyped for five single nucleotide variations (SNVs) in VEGF-A: rs2010963, rs2146323, rs10434, rs833069, and rs6921438.

RESULT

There was a statistically significant difference in allelic distribution of VEGF-A rs833069 polymorphism in relation to the severity of diabetic retinopathy (DRP) (p = 0.031). The allelic distribution of VEGF-A rs2146323 polymorphism tended to be associated with the severity of DRP (p = 0.069). There were no statistically significant differences in the allelic distribution of the studied five SNVs in DME patients regarding the patients' responses to IVR therapy.

CONCLUSIONS

There is no association between the studied VEGF-A SNVs and the responses to IVR therapy in DME. However, the VEGF-A rs833069 gene polymorphism has a clear association with the severity of diabetic retinopathy.

Vascular Endothelial Growth Factor and Ischemic Heart Disease Risk: A Mendelian Randomization Study

BACKGROUND

Vascular endothelial growth factor (VEGF) has angiogenic and possibly proatherosclerotic properties. Observationally it is positively associated with cardiovascular disease, although these observations could be confounded or due to reverse causation. We assessed ischemic heart disease (IHD) risk by genetically predicted VEGF, ie, using Mendelian randomization.

METHODS AND RESULTS

Single nucleotide polymorphisms (SNPs) predicting VEGF level, at genome-wide significance, were applied to the CARDIoGRAMplusC4D 1000 Genomes-based genome-wide association study IHD case (n=60 801)-control (n=123 504) study. We obtained unconfounded estimates using instrumental variable analysis by combining the Wald estimates for each SNP using inverse variance weighting and Mendelian randomization-Egger regression. Based on 9 SNPs independently predicting VEGF (rs1740073 [C6orf223], rs2375981 [KCNV2], rs2639990 [ZADH2], rs4782371 [ZFPM1], rs6921438 [LOC100132354], rs7043199 [VLDLR-AS1], rs10761741 [JMJD1C], rs6993770 [ZFPM2], and rs114694170 [MEF2C]), VEGF was unrelated to IHD (odds ratio 0.99 per log-transformed pg/mL, 95%CI 0.96-1.02) using inverse variance weighting. However, Mendelian randomization-Egger regression suggested an inverse relation of VEGF with IHD (odds ratio 0.95, 95%CI 0.91-0.99), although the association was not evident after excluding the lead SNP (rs6921438) or additionally excluding the pleiotropic SNP (rs6993770).

CONCLUSIONS

Our study does not provide strong evidence for a positive effect of VEGF on IHD but does not rule out the possibility that some specific types of VEGF, for which genetic predictors have not yet been identified, might play a role.

VEGF-related polymorphisms identified by GWAS and risk for major depression

Depression is a common, severe, disabling mental disease that affects millions of people of all ages worldwide. Various studies have shown that neurotrophic/growth factors have a key role in depression and, more specifically, vascular endothelial growth factor (VEGF) is implicated in the pathogenesis of depression. The purpose of this study was to investigate the potential links between four VEGF-related single-nucleotide polymorphisms (SNPs), previously identified through a genome-wide association study (GWAS) and depression. The direct effects and epistatic interactions of the four VEGF-related SNPs (rs10738760, rs6921438, rs6993770 and rs4416670) on depression were investigated through a case-control study including 437 individuals diagnosed with depression and 477 healthy volunteers as controls. Gender, age and body mass index influence was additionally analyzed. The SNP rs4416670 was associated with increased risk for depression (OR: 1.60, P: 0.010). This result demonstrates the existence of relationships between VEGF genetic determinants and depression. This novel association reveals new molecular mechanisms suggesting the potential role of VEGF in depression development that could help to promote a personalized prediction for this severe common disease.

Genome-wide Association Study Identifies 27 Loci Influencing Concentrations of Circulating Cytokines and Growth Factors

Circulating cytokines and growth factors are regulators of inflammation and have been implicated in autoimmune and metabolic diseases. In this genome-wide association study (GWAS) of up to 8,293 Finns we identified 27 genome-widely significant loci (p < 1.2 × 10^-9) for one or more cytokines. Fifteen of the associated variants had expression quantitative trait loci in whole blood. We provide genetic instruments to clarify the causal roles of cytokine signaling and upstream inflammation in immune-related and other chronic diseases. We further link inflammatory markers with variants previously associated with autoimmune diseases such as Crohn disease, multiple sclerosis, and ulcerative colitis and hereby elucidate the molecular mechanisms underpinning these diseases and suggest potential drug targets.

Strain survey and genetic analysis of vasoreactivity in mouse aorta

Understanding the genetic influence on vascular reactivity is important for identifying genes underlying impaired vascular function. The purpose of this study was to characterize the genetic contribution to intrinsic vascular function and to identify loci associated with phenotypic variation in vascular reactivity in mice. Concentration response curves to phenylephrine (PE), potassium chloride (KCl), acetylcholine (ACh), and sodium nitroprusside (SNP) were generated in aortic rings from male mice (12 wk old) from 27 inbred mouse strains. Significant strain-dependent differences were found for both maximal responses and sensitivity for each agent, except for SNP Max (%). Strain differences for maximal responses to ACh, PE, and KCl varied by two- to fivefold. On the basis of these large strain differences, we performed genome-wide association mapping (GWAS) to identify loci associated with variation in responses to these agents. GWAS for responses to ACh identified four significant and 19 suggestive loci. Several suggestive loci for responses to SNP, PE, and KCl (including one significant locus for KCl EC₅₀) were also identified. These results demonstrate that intrinsic endothelial function, and more generally vascular function, is genetically determined and associated with multiple genomic loci. Furthermore, these results are supported by the finding that several genes residing in significant and suggestive loci for responses to ACh were previously identified in rat and/or human quantitative trait loci/GWAS for cardiovascular disease. This study represents the first step toward the unbiased comprehensive discovery of genetic determinants that regulate intrinsic vascular function, particularly endothelial function.

Carriers of a VEGFA enhancer polymorphism selectively binding CHOP/DDIT3 are predisposed to increased circulating levels of thyroid-stimulating hormone

BACKGROUND

Levels of serum thyroid-stimulating hormone (TSH) indicate thyroid function, because thyroid hormone negatively controls TSH release. Genetic variants in the vascular endothelial growth factor A (VEGFA) gene are associated with TSH levels. The aim of this study was to characterise the association of VEGFA variants with TSH in a Danish cohort and to identify and characterise functional variants.

METHODS

We performed an association study of the VEGFA locus for circulating TSH levels in 8445 Danish individuals. Lead variants were tested for allele-specific effects in vitro using luciferase reporter and gel-shift assays.

RESULTS

Four SNPs in VEGFA were associated with circulating TSH (rs9472138, rs881858, rs943080 and rs4711751). For rs881858, the presence of each G-allele was associated with a corresponding decrease in TSH levels of 2.3% (p=8.4×10^-9) and an increase in circulating free T4 levels (p=0.0014). The SNP rs881858 is located in a binding site for CHOP (C/EBP homology protein) and c/EBPβ (ccaat enhancer binding protein β). Reporter-gene analysis showed increased basal enhancer activity of the rs881858 A-allele versus the G-allele (34.5±9.9% (average±SEM), p=0.0012), while co-expression of CHOP effectively suppressed the rs881858 A-allele activity. The A-allele showed stronger binding to CHOP in gel-shift assays.

CONCLUSIONS

VEGF is an important angiogenic signal required for tissue expansion. We show that VEGFA variation giving allele-specific response to transcription factors with overlapping binding sites associate closely with circulating TSH levels. Because CHOP is induced by several types of intracellular stress, this indicates that cellular stress could be involved in the normal or pathophysiological response of the thyroid to TSH.

TRIAL REGISTRATION NUMBER

NCT00289237, NCT00316667; Results.

International Genome-Wide Association Study Consortium Identifies Novel Loci Associated With Blood Pressure in Children and Adolescents

BACKGROUND

Our aim was to identify genetic variants associated with blood pressure (BP) in childhood and adolescence.

METHODS AND RESULTS

Genome-wide association study data from participating European ancestry cohorts of the Early Genetics and Lifecourse Epidemiology (EAGLE) Consortium was meta-analyzed across 3 epochs; prepuberty (4-7 years), puberty (8-12 years), and postpuberty (13-20 years). Two novel loci were identified as having genome-wide associations with systolic BP across specific age epochs: rs1563894 (ITGA11, located in active H3K27Ac mark and transcription factor chromatin immunoprecipitation and 5'-C-phosphate-G-3' methylation site) during prepuberty (P=2.86×10(-8)) and rs872256 during puberty (P=8.67×10(-9)). Several single-nucleotide polymorphism clusters were also associated with childhood BP at P<5×10(-3). Using a P value threshold of <5×10(-3), we found some overlap in variants across the different age epochs within our study and between several single-nucleotide polymorphisms in any of the 3 epochs and adult BP-related single-nucleotide polymorphisms.

CONCLUSIONS

Our results suggest that genetic determinants of BP act from childhood, develop over the lifecourse, and show some evidence of age-specific effects.

Plasma VEGF-related polymorphisms are implied in autoimmune thyroid diseases

Autoimmune thyroid diseases (AITD), including Graves' disease (GD) and Hashimoto thyroiditis (HT), are complex multifactorial diseases. Vascular endothelial growth factor (VEGF) is implicated in various inflammatory diseases, especially autoimmune diseases. Our aim was to elucidate the relationships between plasma VEGF levels and four genome-wide association study-identified single nucleotide polymorphisms (SNPs) related to VEGF with AITD in Tunisian patients. A total of 364 healthy controls and 389 patients with AITD were genotyped for the SNPs rs6921438, rs4416670, rs6993770 and rs10738760. Levels of thyroid hormones and antibodies were quantified simultaneously with plasma VEGF after a period of six months of treatment. We found that the minor alleles of rs10738760 and rs6921438 are associated with the presence of GD. A allele of rs10738760 polymorphism is associated with increased plasma levels of free tri-iodothyronin (FT3) while no relationship was found with circulating VEGF plasma levels after six months of treatment. We also showed that the T allele of rs4416670 polymorphism was associated with increased risk of hyperthyroidism in patients treated for six months, independently of their initial diagnosis. There was no significant association between the SNPs and the risk for HT compared with controls. This study shows that AITD are influenced by 3 SNPs linked to VEGF circulating levels. Whereas rs10738760 appeared specific to GD and FT3 production after six months of treatment, rs6921438 and rs4416670 were implicated in the risk for GD. This study opens new ways to test pharmacogenomics concepts in the future especially in GD in which recurrence prognosis is still challenging.

Six Novel Loci Associated with Circulating VEGF Levels Identified by a Meta-analysis of Genome-Wide Association Studies

Vascular endothelial growth factor (VEGF) is an angiogenic and neurotrophic factor, secreted by endothelial cells, known to impact various physiological and disease processes from cancer to cardiovascular disease and to be pharmacologically modifiable. We sought to identify novel loci associated with circulating VEGF levels through a genome-wide association meta-analysis combining data from European-ancestry individuals and using a dense variant map from 1000 genomes imputation panel. Six discovery cohorts including 13,312 samples were analyzed, followed by in-silico and de-novo replication studies including an additional 2,800 individuals. A total of 10 genome-wide significant variants were identified at 7 loci. Four were novel loci (5q14.3, 10q21.3, 16q24.2 and 18q22.3) and the leading variants at these loci were rs114694170 (MEF2C, P = 6.79x10^-13), rs74506613 (JMJD1C, P = 1.17x10^-19), rs4782371 (ZFPM1, P = 1.59x10^-9) and rs2639990 (ZADH2, P = 1.72x10^-8), respectively. We also identified two new independent variants (rs34528081, VEGFA, P = 1.52x10^-18; rs7043199, VLDLR-AS1, P = 5.12x10^-14) at the 3 previously identified loci and strengthened the evidence for the four previously identified SNPs (rs6921438, LOC100132354, P = 7.39x10^-1467; rs1740073, C6orf223, P = 2.34x10^-17; rs6993770, ZFPM2, P = 2.44x10^-60; rs2375981, KCNV2, P = 1.48x10^-100). These variants collectively explained up to 52% of the VEGF phenotypic variance. We explored biological links between genes in the associated loci using Ingenuity Pathway Analysis that emphasized their roles in embryonic development and function. Gene set enrichment analysis identified the ERK5 pathway as enriched in genes containing VEGF associated variants. eQTL analysis showed, in three of the identified regions, variants acting as both cis and trans eQTLs for multiple genes. Most of these genes, as well as some of those in the associated loci, were involved in platelet biogenesis and functionality, suggesting the importance of this process in regulation of VEGF levels. This work also provided new insights into the involvement of genes implicated in various angiogenesis related pathologies in determining circulating VEGF levels. The understanding of the molecular mechanisms by which the identified genes affect circulating VEGF levels could be important in the development of novel VEGF-related therapies for such diseases.

Vascular Endothelial Growth Factor (VEGF) is a protein with a fundamental role in development of vascular system. The protein, produced by many types of cells, is released in the blood. High levels of VEGF have been observed in different pathological conditions especially in cancer, cardiovascular, and inflammatory diseases. Therefore, identifying the genetic factors influencing VEGF levels is important for predicting and treating such pathologies. The number of genetic variants associated with VEGF levels has been limited. To identify new loci, we have performed a Genome Wide Association Study meta-analysis on a sample of more than 16,000 individuals from 10 cohorts, using a high-density genetic map. This analysis revealed 10 variants associated with VEGF circulating levels, 6 of these being novel associations. The 10 variants cumulatively explain more than 50% of the variability of VEGF serum levels. Our analyses have identified genes known to be involved in angiogenesis related diseases and genes implicated in platelet metabolism, suggesting the importance of links between this process and VEGF regulation. Overall, these data have improved our understanding of the genetic variation underlying circulating VEGF levels. This in turn could guide our response to the challenge posed by various VEGF-related pathologies.

Angiogenesis related genes NOS3, CD14, MMP3 and IL4R are associated to VEGF gene expression and circulating levels in healthy adults

BACKGROUND

Vascular endothelial growth factor (VEGF) plays a key role in angiogenesis. The aim was to assess the genetic connections between the angiogenesis-related NOS3, CD14, MMP3, IL4R, IL4 genes and VEGF expression and plasma levels.

METHODS

The associations between VEGF plasma levels with the polymorphisms of NOS3, CD14, MMP3, IL4R, and IL4 were assessed in 403 healthy unrelated adults. The epistatic and environmental interactions were explored, including four VEGF-related polymorphisms previously identified. The VEGF expression in peripheral blood mononuclear cells was quantified (n = 65) for the VEGF121, VEGF145, VEGF165, and VEGF189 isoforms.

RESULTS

The polymorphism rs1799983 of NOS3 was associated with the sum of all VEGF isoforms mRNA levels (P = 0.032) and VEGF145 (P = 0.033). Rs1800779 of NOS3 interacted with rs3918226 of the same gene and with the rs2569190 of CD14 (P = 0.022, P = 0.042, respectively) for VEGF plasma levels. Other epistatic interactions included the rs1801275 of IL4R with the rs6921438 (VEGF-related variant) and rs3025058 of MMP3 (P = 0.042, P = 0.010 respectively) and the rs2569190 of CD14 with the rs3025058 of MMP3 (P = 0.0119). We also identified an interaction of rs1800779 with obesity, high-density lipoprotein cholesterol and triglycerides (P = 0.018, P = 0.005, P = 0.043, respectively) as well as the interaction of rs6921438 with hypertension (P = 0.028).

CONCLUSIONS

Our findings indicated that genetic variants of NOS3, CD14, MMP3 and IL4R are implicated in the determination of VEGF expression and plasma levels. Thus, they support the hypothesis that in physiological conditions there are complex biological relationships between pathways (such as angiogenesis and inflammation), which are involved in the development of chronic diseases.

VEGF gene promoter polymorphisms and risk of VTE in chemotherapy-treated cancer patients

Among the possible genetic contributors to cancer-related venous thromboembolism (VTE), vascular endothelial growth factor (VEGFA) could play an important role, as an imbalance of the VEGFA system (either disease-related or drug-induced) may result in a disturbance of vascular homeostasis. Thus, this study was designed to investigate the predictive role of eight different VEGFA gene promoter single nucleotide polymorphisms (SNPs) for a first VTE episode in cancer out-patients undergoing chemotherapy. To this purpose, VEGFA gene promoter polymorphisms were analysed in 297 cancer patients using polymerase chain reaction amplification and direct DNA sequencing analysis. One hundred forty unrelated healthy subjects from the same geographical area were also analysed in order to evaluate and compare genotype/haplotype frequencies in our ethnicity. VTE occurred in 26 (9%) of cancer patients with a median time-to-event of 3.4 months. Association analyses showed that -1154G/A polymorphism was significantly associated with the risk of chemotherapy-triggered VTE, with the A allele exerting a protective role both in the overall population (hazard ratio [HR]: 0.21; 95% confidence interval [CI]: 0.07-0.58) or in bevacizumab-treated metastatic patients (HR: 0.09, 95%CI: 0.01-0.86) in whom VEGFA -1154AA genotype also conferred a reduced risk of early progression (HR: 0.58, 95%CI: 0.34-0.98). These results suggest that VEGFA may represent a candidate gene contributing to VTE development in chemotherapy treated cancer patients and that -1154G/A SNP might provide useful clinical information on the efficacy and toxicity of bevacizumab in metastatic patients. Validation studies are needed for translation into clinical practice.