Abstract 497: 5-Methoxytryptophan Protects Against Vascular Remodeling
Vascular smooth muscle cells (VSMCs) in the blood vessel wall exhibit a differentiated phenotype; their main function is contraction and to regulate vascular tone. In response to injury, VSMCs undergo a phenotypic transition whereby they proliferate and migrate from the medial layer into the intima, contributing to lesion formation and atherosclerosis. 5-methoxytryptophan (5-MTP), a recently identified novel tryptophan metabolite, has been shown to inhibit cancer cell growth, migration, and cancer metastasis. We hypothesized that 5-MTP might play an analogous role in vascular disease as in tumorigenesis. To test our hypothesis, we subjected 12 weeks old C57BL/6 mice to a carotid artery cessation of blood flow model to induce neointima formation. Following surgery, mice were treated with vehicle (PBS) or 100 mg/kg of 5-MTP by intraperitoneal injection 3 times a week. Four weeks later, carotid arteries were harvested for histological analysis. H&E and elastin staining revealed robust neointima in ligated carotids of vehicle-treated mice. In contrast, 5-MTP significantly attenuated neointima formation. Given that proinflammatory cytokine interleukin 1 beta (IL-1β) is increased in the injured vessel wall, we examined whether IL-1β affected VSMC phenotypic modulation. Indeed, IL-1β downregulated VSMC marker SM α-actin expression and increased VSMC proliferation and migration. Importantly, in VSMCs, 5-MTP attenuated IL-1β-mediated SM α-actin downregulation, proliferation, and migration, suggesting a potential role of 5-MTP in controlling VSMC phenotypic modulation. Furthermore, 5-MTP inhibited IL-1β-mediated p38 MAPK activation. Inhibiting p38 MAPK activation by SB203580 dose-dependently decreased IL-1β-induced VSMC proliferation. Taken together, our results suggest an important role of 5-MTP in vascular disease.
Author Disclosures: Y. Ho: None. M. Wu: None. C. Su: None. C. Kuo: None. K.K. Wu: None. S. Yet: None.
- © 2015 by American Heart Association, Inc.