Stearic acid alleviates aortic medial degeneration through maintaining mitochondrial dynamics homeostasis via inhibiting JNK/MAPK signaling.

Aortic dissection is characterized pathologically by aortic medial degeneration (AMD) where disturbance of mitochondrial dynamics may be involved. Stearic acid (SA) can promote mitochondrial fusion and improve mitochondrial function. Here, we established an AMD mouse model through oral administration of β-aminopropionitrile (BAPN) and a cellular model by treating primary vascular smooth muscle cells (VSMCs) with Angiotensin-II to explore the potential role of SA in AMD. Our results showed SA reduced AMD and prolonged survival of BAPN-treated mice. Excessive mitochondrial fission was observed during AMD both in vivo and in vitro, and SA reduced mitochondrial fission and increased fusion. Additionally, SA promoted expression of contractile phenotype markers of VSMCs. At the molecular level, SA reduced AMD by inhibiting JNK/MAPK signaling. Our study suggests SA can promote mitochondrial fusion and increase the contractile phenotype of VSMCs by inhibiting JNK/MAPK signaling, thereby reducing AMD formation and possibly the consequent risk of aortic dissection.