9p21.3 Coronary Artery Disease Risk Variants Disrupt TEAD Transcription Factor-Dependent Transforming Growth Factor ß Regulation of p16 Expression in Human Aortic Smooth Muscle Cells.

BACKGROUND: The mechanism whereby the 9p21.3 locus confers risk for coronary artery disease remains incompletely understood. Risk alleles are associated with reduced expression of the cell cycle suppressor genes CDKN2A (p16 and p14) and CDKN2B (p15) and increased vascular smooth muscle cell proliferation. We asked whether risk alleles disrupt transcription factor binding to account for this effect. METHODS AND RESULTS: A bioinformatic screen was used to predict which of 59 single nucleotide polymorphisms at the 9p21.3 locus disrupt (or create) transcription factor binding sites. Electrophoretic mobility shift and luciferase reporter assays examined the binding and functionality of the predicted regulatory sequences. Primary human aortic smooth muscle cells (HAoSMCs) were genotyped for 9p21.3, and HAoSMCs homozygous for the risk allele showed reduced p15 and p16 levels and increased proliferation. rs10811656 and rs4977757 disrupted functional TEF-1 TEC1 AbaA domain (TEAD) transcription factor binding sites. TEAD3 and TEAD4 overexpression induced p16 in HAoSMCs homozygous for the nonrisk allele, but not for the risk allele. Transforming growth factor ß, known to activate p16 and also to interact with TEAD factors, failed to induce p16 or to inhibit proliferation of HAoSMCs homozygous for the risk allele. Knockdown of TEAD3 blocked transforming growth factor ß-induced p16 mRNA and protein expression, and dual knockdown of TEAD3 and TEAD4 markedly reduced p16 expression in heterozygous HAoSMCs. CONCLUSIONS: Here, we identify a novel mechanism whereby sequences at the 9p21.3 risk locus disrupt TEAD factor binding and TEAD3-dependent transforming growth factor ß induction of p16 in HAoSMCs. This mechanism accounts, in part, for the 9p21.3 coronary artery disease risk.

Functional genomics of the 9p21.3 locus for atherosclerosis: clarity or confusion?

The 9p21.3 locus was the first to yield to genome-wide association studies (GWAS) seeking common genetic variants predisposing to increased risk of coronary artery atherosclerotic disease (CAD). The 59 single nucleotide polymorphisms that show highest association with CAD are clustered in a region 100,000 to 150,000 base pairs 5' to the cyclin-dependent kinase inhibitors CDKN2B (coding for p15(ink4b)) and CDKN2A (coding for p16(ink4a) and p14(ARF)). This region also covers the 3' end of a long noncoding RNA transcribed antisense to CDKN2B (CDKN2BAS, aka ANRIL for antisense noncoding RNA at the ink4 locus) whose expression has been linked to chromatin remodeling at the locus. Despite intensive investigation over the past 7 years, the functional significance of the 9p21.3 locus remains elusive. Other variants at this locus have been associated with glaucoma, glioma, and type 2 diabetes mellitus, diseases that implicate tissue-resident macrophages. Here, we review the evidence that genetic variants at 9p21.3 disrupt tissue-specific enhancers and propose new insights to guide future studies.

Low-frequency Coding Variants Associated With Body Mass Index Affect the Success of Bariatric Surgery.

CONTEXT: A recent study identified 14 low-frequency coding variants associated with body mass index (BMI) in 718 734 individuals predominantly of European ancestry. OBJECTIVE: We investigated the association of 2 genetic scores (GS) with i) the risk of severe/morbid obesity, ii) BMI variation before weight-loss intervention, iii) BMI change in response to an 18-month lifestyle/behavioral intervention program, and iv) BMI change up to 24 months after bariatric surgery. METHODS: The 14 low-frequency coding variants were genotyped or sequenced in 342 French adults with severe/morbid obesity and 574 French adult controls from the general population. We built risk and protective GS based on 6 BMI-increasing and 5 BMI-decreasing low-frequency coding variants that were polymorphic in our study. RESULTS: While the risk GS was not associated with severe/morbid obesity status, BMI-decreasing low-frequency coding variants were significantly less frequent in patients with severe/morbid obesity than in French adults from the general population. Neither the risk nor the protective GS was associated with BMI before intervention in patients with severe/morbid obesity, nor did they affect BMI change in response to a lifestyle/behavioral modification program. The protective GS was associated with a greater BMI decrease following bariatric surgery. The risk and protective GS were associated with a higher and lower risk of BMI regain after bariatric surgery. CONCLUSION: Our data indicate that in populations of European descent, low-frequency coding variants associated with BMI in the general population also affect the outcomes of bariatric surgery in patients with severe/morbid obesity.

Medium term post-bariatric surgery deficit of vitamin B12 is predicted by deficit at time of surgery.

BACKGROUND: Patients with morbid obesity have a high risk of deficits in micronutrients, after bariatric surgery. The reasons why systematic use of multivitamin and trace element supplements cannot prevent all deficits are complex and should deserve more attention. Little is known about the influence of micronutrient deficits at surgery. AIM: This present study aimed to explore the deficit in vitamin B12 vs other micronutrients during the follow-up of a French cohort of cases with bariatric surgery under systematic multivitamin/trace elements supplementation and to determine whether it was influenced by clinical, metabolic characteristics at surgery. METHODS: We prospectively enrolled obese patients with bariatric surgery (laparoscopic gastric bypass or laparoscopic sleeve gastrectomy) between 2013 and 2018 (OBESEPI/ALDEPI Cohort, NCT02663388). They received a daily multivitamin/micronutrients supplement. Follow-up data at 4 visits, 2, 12, 18 and 24 months after surgery, were collected. RESULTS: The highest rate of deficits was observed at visit 1 for vitamin D (35.7%), iron (21.9%) and folate (10.2%). Except B12, the deficits of all micronutrients decreased in later visits. In contrast, cases with vitamin B12 deficit decreased from 13.5% at surgery to 2.0% at visit 1, and increased in later visits, with a maximum of 12.0% at visit 3. Vitamin B12 concentration at surgery was the single predictor of B12 deficit at visit 3. It was also associated with age, and APRI score, an index of nonalcoholic fatty liver disease (NAFLD), in multivariate analysis. CONCLUSIONS: The failure of systematic supplementation with multivitamin/trace elements tablets to prevent specific deficits illustrates the need for adapted specific supplementations, in some cases. The worsening of B12 deficit rate in the 18-24 months follow-up depends in part to low B12 at time of surgery. A special consideration should be devoted to this subset of patients. The cohort study was registered at clinicaltrials.gov as NCT02663388.