Journal of Pathology J Pathol 2009; 218: 131–142 Published online 6 January 2009 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/path.2516 Original Paper Syndromic and non-syndromic aneurysms of the human ascending aorta share activation of the Smad2 pathway Delphine Gomez, 1† Ayman Al Haj Zen, 1† Luciano F Borges, 2 Monique Philippe, 1 Paulo Sampaio Gutierrez, 2 Guillaume Jondeau, 1,3 Jean-Baptiste Michel 1 and Roger Vranckx 1 * 1 INSERM, U698, Paris, F-75018 France; Univ Paris 7-Denis Diderot, Paris, F-75018, France 2 Laboratory of Pathology, Instituto do Cora¸ c` ao, University of Sao Paulo. School of Medicine, Brazil 3 AP-HP, Hˆ opital Xavier Bichat, Department of Cardiovascular Medicine and Surgery and the Reference Center for Marfan and Related Syndromes, Paris, France *Correspondence to: Roger Vranckx, INSERM, U698, Hˆ opital Xavier Bichat (Secteur Claude Bernard), 46 Rue Henri Huchard, FR-75877 Paris Cedex 18, France. E-mail: roger.vranckx@inserm.fr † These authors contributed equally to this work. No conflicts of interest were declared. Received: 20 May 2008 Revised: 16 December 2008 Accepted: 20 December 2008 Abstract Common features such as elastic fibre destruction, mucoid accumulation, and smooth muscle cell apoptosis are co-localized in aneurysms of the ascending aorta of various aetiologies. Recent experimental studies reported an activation of TGF-β in aneurysms related to Marfan (and Loeys-Dietz) syndrome. Here we investigate TGF-β signalling in normal and pathological human ascending aortic wall in syndromic and non-syndromic aneurysmal disease. Aneurysmal ascending aortic specimens, classified according to aetiology: syndromic MFS (n = 15, including two mutations in TGFBR2 ), associated with BAV (n = 15) or degenerative forms (n = 19), were examined. We show that the amounts of TGF-β 1 protein retained within and released by aneurysmal tissue were greater than for control aortic tissue, whatever the aetiology, contrasting with an unchanged TGF-β 1 mRNA level. The increase in stored TGF-β 1 was associated with enhanced LTBP-1 protein and mRNA levels. These dysregulations of the extracellular ligand are associated with higher phosphorylated Smad2 and Smad2 mRNA levels in the ascending aortic wall from all types of aneurysm. This activation correlated with the degree of elastic fibre fragmentation. Surprisingly, there was no consistent association between the nuclear location of pSmad2 and extracellular TGF-β 1 and LTBP-1 staining and between their respective mRNA expressions. In parallel, decorin was focally increased in aneurysmal media, whereas biglycan was globally decreased in aneurysmal aortas. In conclusion, this study highlights independent dysregulations of TGF-β retention and Smad2 signalling in syndromic and non-syndromic aneurysms of the ascending aorta. Copyright  2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Keywords: Marfan syndrome; bicuspid aortic valves; TGF-β ; LTBP-1; proteoglycans; PAI-1; decorin Introduction In contrast with abdominal aortic aneurysm, mainly due to atherosclerosis, aetiologies of aneurysm of the ascending aorta are less well characterized and appear to be multiple [1]. However, whatever the aetiology [2] — genetic, syndromic forms associated with mutations in FBN1, TGFBR1 or TGFBR2 [3–5] (mainly Marfan syndrome [6]), MYH11 [7], ACTA2 [8], GLUT10 [9]; aneurysms associated with the bicus- pid aortic valve (BAV) [10]; or degenerative forms [11] — they all present common histopathological features such as elastolysis and collagenolysis, accu- mulation of mucoid material [12,13], and smooth muscle cell (SMC) apoptosis [14–16]. In this con- text, it has been recently proposed that transform- ing growth factor-beta (TGF-β ) plays a predominant pathophysiological role in Marfan mutation-induced aneurysms of the ascending aorta [6]. (TGF-β , a multifunctional cytokine, plays a key role in embryo morphogenesis, differentiation, apop- tosis, and extracellular matrix integrity [17–19]. These effects result from the binding of TGF-β 1 to transmembrane receptors with a cytoplasmic ser- ine/threonine kinase domain. TGF-β 1 and TGF-β receptor types I and II activate several pathways, including Smad-dependent and Smad-independent pathways [20]. Smads are a family of transcriptional factors critical for transmitting immediate signals from TGF-β receptors to the nucleus, where they regulate the expression of multiple targets [21]: matrix proteins (collagen, fibronectin [22]), matrix metalloproteinases (MMP-2 [23]), and members of the fibrinolytic system [plasminogen activator inhibitor-1 (PAI-1) [24]]. Copyright  2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk