ADTRP regulates TFPI expression via transcription factor POU1F1 involved in coronary artery disease

An epigenome-wide association study of waist circumference in Chinese monozygotic twins

OBJECTIVES

Central obesity poses significant health risks because it increases susceptibility to multiple chronic diseases. Epigenetic features such as DNA methylation may be associated with specific obesity traits, which could help us understand how genetic and environmental factors interact to influence the development of obesity. This study aims to identify DNA methylation sites associated with the waist circumference (WC) in Northern Han Chinese population, and to elucidate potential causal relationships.

METHODS

A total of 59 pairs of WC discordant monozygotic twins (ΔWC >0) were selected from the Qingdao Twin Registry in China. Generalized estimated equation model was employed to estimate the methylation levels of CpG sites on WC. Causal relationships between methylation and WC were assessed through the examination of family confounding factors using FAmiliaL CONfounding (ICE FALCON). Additionally, the findings of the epigenome-wide analysis were corroborated in the validation stage.

RESULTS

We identified 26 CpG sites with differential methylation reached false discovery rate (FDR) < 0.05 and 22 differentially methylated regions (slk-corrected p < 0.05) strongly linked to WC. These findings provided annotations for 26 genes, with notable emphasis on MMP17, ITGA11, COL23A1, TFPI, A2ML1-AS1, MRGPRE, C2orf82, and NINJ2. ICE FALCON analysis indicated the DNA methylation of ITGA11 and TFPI had a causal effect on WC and vice versa (p < 0.05). Subsequent validation analysis successfully replicated 10 (p < 0.05) out of the 26 identified sites.

CONCLUSIONS

Our research has ascertained an association between specific epigenetic variations and WC in the Northern Han Chinese population. These DNA methylation features can offer fresh insights into the epigenetic regulation of obesity and WC as well as hints to plausible biological mechanisms.

Sex Differences in Delayed Hospitalization in Patients with Non-ST-Segment Elevation Myocardial Infarction Undergoing New-Generation Drug-Eluting Stent Implantation

We compared the effects of sex differences in delayed hospitalization (symptom-to-door time [SDT], ≥24 h) on major clinical outcomes in patients with non-ST-segment elevation myocardial infarction after new-generation drug-eluting stent implantation. A total of 4593 patients were classified into groups with (n = 1276) and without delayed hospitalization (SDT < 24 h, n = 3317). Thereafter, these two groups were subdivided into male and female groups. The primary clinical outcomes were major adverse cardiac and cerebrovascular events (MACCE), defined as all-cause death, recurrent myocardial infarction, repeat coronary revascularization, and stroke. The secondary clinical outcome was stent thrombosis. After multivariable- and propensity score-adjusted analyses, in-hospital mortalities were similar between the male and female groups in both the SDT < 24 h and SDT ≥ 24 h groups. However, during a 3-year follow-up period, in the SDT < 24 h group, all-cause death (p = 0.013 and p = 0.005, respectively) and cardiac death (CD, p = 0.015 and p = 0.008, respectively) rates were significantly higher in the female group than those in the male group. This may be related to the lower all-cause death and CD rates (p = 0.022 and p = 0.012, respectively) in the SDT < 24 h group than in the SDT ≥ 24 h group among male patients. Other outcomes were similar between the male and female groups and between the SDT < 24 h and SDT ≥ 24 h groups. In this prospective cohort study, female patients showed higher 3-year mortality, especially in the SDT < 24 h, compared to male patients.

Genetic parameters estimation and genome molecular marker identification for gestation length in pigs

Gestation length (GL) plays an important role in piglet maturation of major organs and development of body, while the genetic molecular markers of GL have not been extensively identified. In this study, according to the 5,662 effective records of 3,072 sows, the heritability and repeatability of GL were estimated through the dmuai of DMU Version 6.5.1 with a repeatability model, namely, h 2 = 0.1594 and r e 2 = 0.2437. Among these sows, 906 individuals were genotyped with the GeneSeek Genomic Profiler (GGP) Porcine 50K Chip and imputed to the genome-wide level (9,212,179 SNPs) by the online software PHARP v1 for subsequent quality control and GWAS analyses. Further, the Fst was also performed to measure whether the actual frequency of genotypes in different GL phenotypes deviated from the theoretical proportion of genetic balance. We observed the highest degree of differentiation (average Fst value = 0.0376) in the group of 114 and 118 days, and identified a total of 1,002 SNPs strongly associated with GL. Through screening the genes located within a 500 kb distance on either side of the significant SNPs, we proposed 4,588 candidate genes. By the functional annotation, these candidates were found to be mainly involved in multicellular organism metabolism, early endosome, embryo implantation and development, and body and organ signaling pathway. Because of the simultaneous confirmation by GWAS and Fst analyses, there were 20 genes replied to be the most promising candidates including HUNK, ARHGDIB, ERP27, RERG, NEDD9, TMEM170B, SCAF4, SOD1, TIAM1, ENSSSCG00000048838, ENSSSCG00000047227, EDN1, HIVEP1, ENSSSCG00000043944, LRATD1, ENSSSCG00000048577, ENSSSCG00000042932, ENSSSCG00000041405, ENSSSCG00000045589, and ADTRP. This study provided effective molecular information for the genetic improvement of GL in pigs.

Functional rare variant in a C/EBP beta binding site in NINJ2 gene increases the risk of coronary artery disease

Objective: NINJ2 regulates activation of vascular endothelial cells, and genome-wide association studies showed that variants in NINJ2 confer risk to stroke. However, whether variants in NINJ2 are associated with coronary artery disease (CAD) is unknown.

Methods: We genotyped rs34166160 in NINJ2 in two independent Chinese GeneID populations which included 2,794 CAD cases and 4,131 controls, and performed genetics association studies. Functional studies were also performed to reveal the mechanisms.

Results: Allele rs34166160 significantly confers risk to CAD in the GeneID Hubei population which contained 1,440 CAD cases and 2,660 CAD-free controls (observed P_-obs = 6.39 × 10⁻³ with an odds ratio (OR) was 3.39, adjusted P_-adj = 8.12 × 10⁻³ with an OR of 3.10). The association was replicated in another population, GeneID Shandong population contained 1,354 CAD cases and 1,471 controls (P_-obs = 3.33 × 10⁻³ with an OR of 3.14, P_-adj = 0.01 with an OR of 2.74). After combining the two populations, the association was more significant (P_-obs = 1.57 × 10⁻⁵ with an OR of 3.58, P_-adj = 3.41 × 10⁻⁴ with an OR of 2.80). In addition, we found that rs34166160 was associated with the mRNA expression level of NINJ2 and the flanking region of rs34166160 can directly bind with transcriptional factor CCAAT-box/enhancer-binding protein beta, and the risk A allele has more transcription activity than non-risk C allele with or without LPS in HUVEC cells.

Conclusions: Our study demonstrates that the functional rare variant rs34166160 in NINJ2 confers risk to CAD for the first time, and these findings further expand the range of the pathology of CAD and atherosclerosis.

Androgen-dependent tissue factor pathway inhibitor regulating protein: a review of its peripheral actions and association with cardiometabolic diseases

The first genome-wide association study on coronary artery disease (CAD) in the Han Chinese population identified C6orf105 as a susceptibility gene. The C6orf105 gene was later found to encode for a protein that regulates tissue factor pathway inhibitor (TFPI) expression in endothelial cells in an androgen-dependent manner, and the novel protein was thus termed androgen-dependent TFPI-regulating protein (ADTRP). Since the identification of ADTRP, there have been several studies associating genetic variants on the ADTRP gene with CAD risk, as well as research providing mechanistic insights on this novel protein and its functional role. ADTRP is a membrane protein, whose expression is upregulated by androgen, GATA-binding protein 2, oxidized low-density lipoprotein, peroxisome proliferator-activated receptors, and low-density lipoprotein receptors. ADTRP regulates multiple downstream targets involved in coagulation, inflammation, endothelial function, and vascular integrity. In addition, ADTRP functions as a fatty acid esters of hydroxy fatty acid (FAHFA)-specific hydrolase that is involved in energy metabolism. Current evidence suggests that ADTRP may play a role in the pathogenesis of atherosclerosis, CAD, obesity, and metabolic disorders. This review summarizes the current literature on ADTRP, with a focus on the peripheral actions of ADTRP, including expression, genetic variations, signaling pathways, and function. The evidence linking ADTRP and cardiometabolic diseases will also be discussed.

Molecular Phylogenetic Analysis of the AIG Family in Vertebrates

Androgen-inducible genes (AIGs), which can be regulated by androgen level, constitute a group of genes characterized by the presence of the AIG/FAR-17a domain in its protein sequence. Previous studies on AIGs demonstrated that one member of the gene family, AIG1, is involved in many biological processes in cancer cell lines and that ADTRP is associated with cardiovascular diseases. It has been shown that the numbers of AIG paralogs in humans, mice, and zebrafish are 2, 2, and 3, respectively, indicating possible gene duplication events during vertebrate evolution. Therefore, classifying subgroups of AIGs and identifying the homologs of each AIG member are important to characterize this novel gene family further. In this study, vertebrate AIGs were phylogenetically grouped into three major clades, ADTRP, AIG1, and AIG-L, with AIG-L also evident in an outgroup consisting of invertebrsate species. In this case, AIG-L, as the ancestral AIG, gave rise to ADTRP and AIG1 after two rounds of whole-genome duplications during vertebrate evolution. Then, the AIG family, which was exposed to purifying forces during evolution, lost or gained some of its members in some species. For example, in eutherians, Neognathae, and Percomorphaceae, AIG-L was lost; in contrast, Salmonidae and Cyprinidae acquired additional AIG copies. In conclusion, this study provides a comprehensive molecular phylogenetic analysis of vertebrate AIGs, which can be employed for future functional characterization of AIGs.

Knockdown screening of chromatin binding and regulatory proteins in zebrafish identified Suz12b as a regulator of tfpia and an antithrombotic drug target

Tissue factor pathway inhibitor (TFPI) is an anticoagulant protein that inhibits factor VIIa and Xa in the coagulation cascade. It has been shown that forkhead box P3 protein is a TFPI transcriptional repressor. However, there are no studies on chromatin remodeling that control TFPI expression. We hypothesized that the genome-wide knockdowns of the chromatin binding and regulatory proteins (CBRPs) in zebrafish could identify novel tfpia gene regulators. As an initial step, we selected 69 CBRP genes from the list of zebrafish thrombocyte-expressed genes. We then performed a 3-gene piggyback knockdown screen of these 69 genes, followed by quantification of tfpia mRNA levels. The results revealed that knockdown of brd7, ing2, ing3, ing4, and suz12b increased tfpia mRNA levels. The simultaneous knockdown of these 5 genes also increased tfpia mRNA levels. We also performed individual gene and simultaneous 5-gene knockdowns on the 5 genes in zebrafish larvae. We found that after laser injury, it took a longer time for the formation of the thrombus to occlude the caudal vessel compared to the control larvae. We then treated the larvae and adults with a chemical UNC6852 known to proteolytically degrade polycomb repressor complex 2, where SUZ12 is a member, and observed prolongation of time to occlude (TTO) the caudal vein after laser injury and increased tfpia mRNA levels in larvae and adults, respectively. In summary, our results have identified novel epigenetic regulators for tfpia and exploited this information to discover a drug that enhances tfpia mRNA levels and prolongation of TTO. This discovery provides the basis for testing whether UNC6852 could be used as an antithrombotic drug. This approach could be used to study the regulation of other plasma proteins, including coagulant and anticoagulant factors.

Insights into the Functional Role of ADTRP (Androgen-Dependent TFPI-Regulating Protein) in Health and Disease

The novel protein ADTRP, identified and described by us in 2011, is androgen-inducible and regulates the expression and activity of Tissue Factor Pathway Inhibitor, the major inhibitor of the Tissue Factor-dependent pathway of coagulation on endothelial cells. Single-nucleotide polymorphisms in ADTRP associate with coronary artery disease and myocardial infarction, and deep vein thrombosis/venous thromboembolism. Some athero-protective effects of androgen could exert through up-regulation of ADTRP expression. We discovered a critical role of ADTRP in vascular development and vessel integrity and function, manifested through Wnt signaling-dependent regulation of matrix metalloproteinase-9. ADTRP also hydrolyses fatty acid esters of hydroxy-fatty acids, which have anti-diabetic and anti-inflammatory effects and can control metabolic disorders. Here we summarize and analyze the knowledge on ADTRP and try to decipher its functions in health and disease.

GATA2 regulates the CAD susceptibility gene ADTRP rs6903956 through preferential interaction with the G allele

Myocardial infarction (MI) is a frequent outcome of coronary artery disease (CAD) and the key factor contributing to worldwide disability and death. Genetic factors contribute to the pathogenesis of CAD/MI, and SNP rs6903956 in the ADTRP gene was first found associated with CAD/MI in the Chinese Han population, which was successfully replicated in other cohorts. However, whether rs6903956 is a functional SNP and its risk mechanism to CAD/MI remains unknown. The ADTRP gene-encoded androgen-dependent TFPI regulating protein regulates vascular endothelial cell function, endothelial-monocyte adhesion, and thrombosis. The allele A of rs6903956, in particular, is associated with lower ADTRP mRNA levels in lymphocytes. In the current study, we found that SNP rs6903956 exhibits allelic differences in transcriptional activity by interacting with GATA2. Also, the A allele conferred a greater risk of CAD and MI, lowered transcriptional activity, and GATA2 binding ability as compared to the G allele. Our findings provide details on how rs6903956 regulates the expression of ADTRP and may provide novel insights into CAD pathology and susceptibility.

Feedback regulation of coronary artery disease susceptibility gene ADTRP and LDL receptors LDLR/CD36/LOX-1 in endothelia cell functions involved in atherosclerosis

A high level of low-density lipoprotein cholesterol (LDL) is one of the most important risk factors for coronary artery disease (CAD), the leading cause of death worldwide. However, a low concentration of LDL may be protective. Genome-wide association studies revealed that variation in ADTRP gene increased the risk of CAD. In this study, we found that a low concentration of oxidized-LDL induced the expression of ADTRP. Further analyses showed that knockdown of the expression of LDL receptor genes LDLR, CD36, or LOX-1 significantly downregulated ADTRP expression, whereas overexpression of LDLR/CD36/LOX-1 markedly increased ADTRP expression through the NF-κB pathway. Like ADTRP, LDLR, CD36 and LOX-1 were all involved in endothelial cell (EC) functions relevant to the initiation of atherosclerosis. Downregulation of LDLR/CD36/LOX-1 promoted monocyte adhesion to ECs and transendothelial migration of monocytes by increasing expression of ICAM-1, VCAM-1, E-selectin and P-selectin, decreased EC proliferation and migration, and increased EC apoptosis, thereby promoting the initiation of atherosclerosis. Opposite effects were observed with the overexpression of ADTRP and LDLR/CD36/LOX-1 in ECs. Interestingly, through the NF-κB and AKT pathways, overexpression of ADTRP significantly upregulated the expression of LDLR, CD36, and LOX-1, and knockdown of ADTRP expression significantly downregulated the expression of LDLR, CD36, and LOX-1. These data suggest that ADTRP and LDL receptors LDLR/CD36/LOX-1 positively regulate each other, and form a positive regulatory loop that regulates endothelial cell functions, thereby providing a potential protective mechanism against atherosclerosis. Our findings provide a new molecular mechanism by which deregulation of ADTRP and LDLR/CD36/LOX-1 promote the development of atherosclerosis and CAD.