Abstract P108: Wnt Pathway Gene Expression is Associated With Greater Arterial Stiffness

Abstract

The wingless (Wnt) pathway is known to regulate many systems, including embryonic development, bone mineralization, and cancer. Now there is emerging evidence from Basic and our own Population research that Wnt pathway activation is associated with cardiovascular disease (CVD) pathologies, including atherosclerosis and arterial stiffening. However, research on this association in humans is still under-studied and limited in scope. As such, we aimed to survey the entire Wnt signaling pathway for association with subclinical CVD, using a custom gene expression panel (Nanostring, Seattle, WA) of 43 Wnt genes with previous Basic research evidence for a role in vascular disease. We ran this panel in stabilized peripheral blood RNA from 369 African Ancestry men in the Tobago Health Study (mean age 64 years, range 51-89 years). Subclinical CVD assessments were completed at the same study visit as the blood draw, including: arterial stiffness measured by brachial-ankle pulse-wave velocity; atherosclerosis measures of carotid plaque and intima-media thickness via B-mode ultrasonography; and vascular calcification measured by computed tomography in the chest (coronary) and abdomen (aorta). Gene expression was measured in counts per sample, was normalized to housekeeping genes, and the background signal was subtracted. All gene expression and outcome measures were transformed to normality after excluding any extreme outliers. Fourteen Wnt genes showed variable expression in our sample and were tested individually as predictors of subclinical CVD using multiple linear or logistic regression, as appropriate. A conservative Bonferroni-corrected alpha (0.05/14 genes = 0.0036) was used to account for multiple comparisons in unadjusted models. Associations passing this threshold were then adjusted for common CVD risk factors including age, height, weight, hypertension, pulse, diabetes, smoking, alcohol intake, and sedentary lifestyle. After full adjustment, expression of APC, WNT signaling pathway regulator ( APC ) and transcription factor 4 ( TCF4 ) showed significant association with arterial stiffness (P=0.012 for both). When entered into a single model (Spearman r=0.14, P=0.007), APC and TCF4 expression were independently associated with arterial stiffness (P=0.004 for both), such that higher expression of APC , but lower expression of TCF4 , was associated with greater arterial stiffness. No other tested genes or subclinical CVD measures passed both the conservative unadjusted alpha level and the full model adjustment. This study represents the first test of the association between broad Wnt signaling pathway gene expression and subclinical CVD. While APC and TCF4 have shown some association with vascular pathologies in Basic research, this is the first study to establish the association of their expression with human arterial stiffness.