Abstract 351: Focal Adhesion Kinase Promotes Tissue Destruction in Aortic Dissection in Mice

Aortic dissection (AD) is a fatal disease due to the sudden destruction of the aortic medial layer. Currently, Molecular pathogenesis of AD is unknown. We investigated the role of focal adhesion kinase (FAK), a mechanosensitive signal transducer, in AD pathogenesis. We created a mouse model of AD with a continuous infusion of beta-aminopropionitrile (150 mg/kg/day), a collagen crosslink inhibitor, and angiotensin II (1,000 ng/kg/min) (BAPN + Ang II) by osmotic pumps. This AD model showed about 60% mortality within 2 weeks due to AD rupture. Immunohistochemical staining for activated FAK revealed that FAK was inactive in normal mouse aorta, but was strongly activated in the aortic walls after BAPN + Ang II infusion. Immunofluorescence staining showed that FAK was activated mainly in smooth muscle cells after the BAPN + Ang II challenge. Western blot analysis revealed that FAK was activated in 3 days after BAPN + Ang II infusion before AD development, followed by transient reduction at day 7, and re-activation after AD development at day 14. We examined the effect of PND-1186, an orally available FAK inhibitor, on the severity as determined by the AD lesion length and the mortality of AD. Mice were administered with either vehicle or PND-1186 (150 mg/kg twice daily by oral gavage) during the BAPN + Ang II challenge (n=20 for each group). Administration of PND-1186 resulted in significant reduction in the lesion length of AD (vehicle; 12.5 ± 1.65 mm, PND; 7.46 ± 1.88 mm, P<0.05). The suppressive effect of PND-1186 was most significant in the aortic arch (vehicle; 2.13 ± 0.29 mm, PND; 0.85 ± 0.22 mm, P<0.01). Furthermore, PND-1186 significantly improved the survival rate of mice from 40.0% to 80.0% (P<0.01). Transcriptome analysis indicated that destruction and inflammation of tissue were suppressed by PND-1186 administration. These findings indicated that FAK plays an important role in AD pathogenesis, possibly by transducing the pathological stress to the tissue destructive response in the aortic walls. We propose that FAK is a potential therapeutic target to limit the fatal destruction of aortic walls in AD.