Epigenetic Profiling Identifies Novel Genes for Ascending Aortic Aneurysm Formation with Bicuspid Aortic Valves
DOI:
https://doi.org/10.1532/hsf.1247Abstract
Background: Bicuspid aortic valves predispose to ascending aortic aneurysms, but the mechanisms underlying this aortopathy remain incompletely characterized. We sought to identify epigenetic pathways predisposing to aneurysm formation in bicuspid patients.
Methods: Ascending aortic aneurysm tissue samples were collected at the time of aortic replacement in subjects with bicuspid and trileaflet aortic valves. Genome-wide DNA methylation status was determined on DNA from tissue using the Illumina 450K methylation chip, and gene expression was profiled on the same samples using Illumina Whole-Genome DASL arrays. Gene methylation and expression were compared between bicuspid and trileaflet individuals using an unadjusted Wilcoxon rank sum test.
Results: Twenty-seven probes in 9 genes showed significant differential methylation and expression (P<5.5x10-4). The top gene was protein tyrosine phosphatase, non-receptor type 22 (PTPN22), which was hypermethylated (delta beta range: +15.4 to +16.0%) and underexpressed (log 2 gene expression intensity: bicuspid 5.1 vs. trileaflet 7.9, P=2x10-5) in bicuspid patients, as compared to tricuspid patients. Numerous genes involved in cardiovascular development were also differentially methylated, but not differentially expressed, including ACTA2 (4 probes, delta beta range: -10.0 to -22.9%), which when mutated causes the syndrome of familial thoracic aortic aneurysms and dissections
Conclusions: Using an integrated, unbiased genomic approach, we have identified novel genes associated with ascending aortic aneurysms in patients with bicuspid aortic valves, modulated through epigenetic mechanisms. The top gene was PTPN22, which is involved in T-cell receptor signaling and associated with various immune disorders. These differences highlight novel potential mechanisms of aneurysm development in the bicuspid population.
References
Tadros TM, Klein MD, Shapira OM. Ascending aortic dilatation associated with bicuspid aortic valve: pathophysiology, molecular biology, and clinical implications. Circulation. 2009;119:880-90.
Cripe L, Andelfinger G, Martin LJ, Shooner K, Benson DW. Bicuspid aortic valve is heritable. J Am Coll Cardiol. 2004;44:138-43.
Wagner KW, Alam H, Dhar SS, et al. KDM2A promotes lung tumorigenesis by epigenetically enhancing ERK1/2 signaling. J Clin Invest 2013;123:5231-46.
Brock MV, Hooker CM, Emi Ota-Machida, M.D., Ph.D., et al. DNA Methylation Markers and Early Recurrence in Stage I Lung Cancer. N Engl J Med 2008;358:1118-28.
Akhtar-Zaidi B, Cowper-Sal-lari R, Corradin O, et al. Epigenomic enhancer profiling defines a signature of colon cancer. Science 2012;336:736-9.
Puig-Vilanova E, Aguiló R, RodrÃguez-Fuster A, MartÃnez-Llorens J, Gea J, Barreiro E. Epigenetic mechanisms in respiratory muscle dysfunction of patients with chronic obstructive pulmonary disease. PLoS One 2014 Nov;9:e111514.
Gilsbach R, Preissl S, Grüning BA, et al. Dynamic DNA methylation orchestrates cardiomyocyte development, maturation and disease. Nat Commun 2014;5:5288.
Zaidi S, Choi M, Wakimoto H, et al. De novo mutations in histone-modifying genes in congenital heart disease. Nature 2013;498:220-3.
Baccarelli A1, Rienstra M, Benjamin EJ. Cardiovascular epigenetics: basic concepts and results from animal and human studies. Circ Cardiovasc Genet 2010;3:567-73.
Hiratzka LF, Bakris GL, Beckman JA, et al. ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation. 2010;121:e266-369.
Fan JB, Yeakley JM, Bibikova M, et al. A versatile assay for high-throughput gene expression profiling on universal array matrices. Genome Res 2004;14:878–85.
Prakash SK, Bossé Y, Muehlschlegel J, et al. A roadmap to investigate the genetic basis of bicuspid aortic valve and its complications: insights from the International BAVCon (Bicuspid Aortic Valve Consortium). J Am Coll Cardiol 2014;64:832-9.
Phillippi JA, Klyachko EA, Kenny JP 4th, Eskay MA, Gorman RC, Gleason TG. Basal and oxidative stress-induced expression of metallothionein is decreased in ascending aortic aneurysms of bicuspid aortic valve patients. Circulation 2009;119:2498-506.
Sievers HH, Sievers HL. Aortopathy in bicuspid aortic valve disease - genes or hemodynamics? or Scylla and Charybdis? Eur J Card Surg 2011:39;803-4.
Burn GL, Svensson L, Sanchez-Blanco C, Saini M, Cope AP. Why is PTPN22 a good candidate susceptibility gene for autoimmune disease? FEBS Lett. 2011;585:3689-98.
Zhang J, Zahir N, Jiang Q, et al. The autoimmune disease-associated PTPN22 variant promotes calpain-mediated Lyp/Pep degradation associated with lymphocyte and dendritic cell hyperresponsiveness. Nat Genet 2011;43:902-7.
He R, Guo DC, Sun W, et al. Characterization of the inflammatory cells in ascending thoracic aortic aneurysms in patients with Marfan syndrome, familial thoracic aortic aneurysms, and sporadic aneurysms. J Thorac Cardiovasc Surg 2008;136:922-9.
Duprez L, Bertrand MJ, Vanden Berghe T, Dondelinger Y, Festjens N, Vandenabeele P.
Intermediate domain of receptor-interacting protein kinase 1 (RIPK1) determines switch between necroptosis and RIPK1 kinase-dependent apoptosis. J Biol Chem 2012;287:14863-72.
Hsu RM, Tsai MH, Hsieh YJ, Lyu PC, Yu JS. Identification of MYO18A as a novel interacting partner of the PAK2/betaPIX/GIT1 complex and its potential function in modulating epithelial cell migration. Mol Biol Cell 2010;21:287-301.
Guo H, Zhu P, Yan L, et al. The DNA methylation landscape of human early embryos.
Nature 2014;511:606-10.
Guo DC, Pannu H, Tran-Fadulu V, et al. Mutations in smooth muscle alpha-actin (ACTA2) lead to thoracic aortic aneurysms and dissections. Nat Genet 2007;39:1488-93.
Xin M, Davis CA, Molkentin JD, et al. A threshold of GATA4 and GATA6 expression is required for cardiovascular development. Proc Natl Acad Sci USA 2006;103:11189-94.
