Differential Proteomic Research On The Media Of Human Thoracic Aortic Dissection

Objective: Thoracic aortic dissection (TAD) is one of the most catastrophic aortic disease. Many patients that suffer TAD still occur rupture and die before diagnosis and treatment. An overall study from the angle of TAD pathogenesis wouid be beneficial for us to diagnose earlier, treat better and even prevent itsdevelopment and progression. This study was performed to investigate the differentially expressed proteins of the aortic medias between diseased aorta of TAD (DA) and normal thoracic aorta (NA) by proteomic technique with the aim to find out the key proteins involved in TAD development and their possible roles in TAD. Methods : Two-dimensional electrophoresis(2DE) was used to separate the proteomes of DA from six TAD patients undergoing repair surgery and six control NA from six organ donators without aortic diseases. Images of Silver-stained 2D gels were analyzed by PDQuest software. Using matrix-assisted laser desorption/ionization-time of flight MS(MALDI-TOF-MS) and/or MA1DI-TOF/TOF-MS, twenty-six protein spots of differential expression were identified. Two identified protein was selected for further research. The expression and location of protein and even its role in TAD formation were observed using immunohistology and Western Blotting. Results: ①Both of the match ratios of the proteomic profiles of DA and NA repeated for three times were 89.5%, which means a good replication. Image analysis revealed that 126 protein spots showed more than 2 folds differential expression in DA compared to NA, of which 54 spots showed more than 5 folds expression changes. ②Twenty-six spots identified by MS included several cytoskletal proteins such as SM22 α, destrin, α-actinin-2 associated LIM protein and skeletal muscle LIM-protein FHL1. Heat shock protein 27(HSP27), extracellular superoxide dismutase(EC-SOD) and osteoglycin also identified with decreased expression in TAD. Others identified proteins included transferrin and some serum proteins. ③There was an accumulation of glycosaminoglycan(GAG) in the matrix of DA. ④HSP27 expressed in both DA (n=15) and NA (n=15) , and SMCs were the main cellular source. Western Blot showed that HSP27 and EC-SOD expression decreased in DA compared with NA. ⑤Oxidative stress associated markers malondialdehyde (MDA) increased in DA compared with NA, while the ability of anti-superoxide anion decreased or producing- superoxide anion increased in DA. Activities of SOD were decreased in DA. Conclusions: This study provides an important knowledge of thoracic aorta media proteins expression in vivo. Differential expressed proteins between DA and NA included some cytoskeletal proteins and proteins associated with oxidative stress and inflammation as well as other proteins, and proteins such as osteoglycin, EC—SOD , HSP27 and SM22 a were firstly demonstrated in TAD. The accumulation of GAG in the matrix of DA may be one of the specific pathological characters of TAD. DA existed oxidative injury, and oxidative stress increased in TAD. HSP27 and EC-SOD may play important roles in TAD pathogenesis partially through mechanisms of oxidative stress and SMC regulation.