Abstract
Aortic dissection (AD) is a catastrophic vascular emergency with high mortality, and current pharmacological interventions to prevent its progression are limited. Vascular smooth muscle cells (VSMCs) undergo a pathological phenotypic switch from a contractile to a synthetic state during AD, compromising aortic wall integrity; however, the underlying metabolic mechanisms remain poorly understood. In this study, we performed integrative transcriptomic analyses and identified glutaminase 1 (GLS1) as a key regulator of VSMC phenotypic switching in AD. GLS1 expression was significantly downregulated in VSMCs from both human AD aortic tissues and mouse models. Functionally, GLS1 deficiency promoted PDGF-BB–induced VSMC dedifferentiation in vitro. Smooth muscle cell–specific Gls1-knockout (Gls1SMKO) mice exhibited aggravated AD after β-aminopropionitrile treatment, whereas VSMC-specific GLS1 overexpression improved the contractile phenotype and reduced AD incidence. Mechanistically, GLS1 downregulation impaired glutamate metabolism, leading to reduced levels of glutathione and α-ketoglutarate. This metabolic disruption promoted reactive oxygen species accumulation and mitochondrial dysfunction, ultimately triggering VSMC phenotypic switching. Furthermore, we found that GLS1 transcription was repressed by retinoic acid receptor-α (RARα). Pharmacological inhibition of RARα with AR7 restored GLS1 expression, ameliorated VSMC phenotypic switching, and conferred protection against AD. These findings reveal a critical role of GLS1-mediated glutamate metabolism in VSMC phenotypic switching and suggest a promising therapeutic strategy for AD.
Authors
Wei Xie, Chen Ning, Chen Lu, Dongjin Wang, Shuang Zhao, Tianyu Song, Hailong Cao
