Cigarette smoke extract induces ferroptosis in vascular smooth muscle cells

Abstract

Cigarette smoking is a major risk factor for aortic aneurysm and dissection; however, no causative link between smoking and these aortic disorders has been proven. In the present study, we investigated the mechanism by which cigarette smoke affects vascular wall cells and found that cigarette smoke extract (CSE) induced a novel form of regulated cell death termed ferroptosis in vascular smooth muscle cells (VSMCs). CSE markedly induced cell death in A7r5 cells and primary rat VSMCs, but not in endothelial cells, which was completely inhibited by specific ferroptosis inhibitors [ferrostatin-1 (Fer-1) and Liproxstatin-1] and an iron chelator (deferoxamine). CSE-induced VSMC death was partially inhibited by a GSH precursor ( N-acetyl cysteine) and an NADPH oxidase inhibitor [diphenyleneiodonium chloride (DPI)], but not by inhibitors of pan-caspases (Z-VAD), caspase-1 (Z-YVAD), or necroptosis (necrostatin-1). CSE also upregulated IL-1β, IL-6, TNF-α, matrix metalloproteinase (MMP)-2, MMP-9, and TIMP-1 (tissue inhibitor of metalloproteinase)in A7r5 cells, which was inhibited by Fer-1. Furthermore, CSE induced the upregulation of Ptgs2 mRNA, lipid peroxidation, and intracellular GSH depletion, which are key features of ferroptosis. VSMC ferroptosis was induced by acrolein and methyl vinyl ketone, major constituents of CSE. Furthermore, CSE caused medial VSMC loss in ex vivo aortas. Electron microscopy analysis showed mitochondrial damage and fragmentation in medial VSMCs of CSE-treated aortas. All of these manifestations were partially restored by Fer-1. These findings demonstrate that ferroptosis is responsible for CSE-induced VSMC death and suggest that ferroptosis is a potential therapeutic target for preventing aortic aneurysm and dissection. NEW & NOTEWORTHY Cigarette smoke extract (CSE)-induced cell death in rat vascular smooth muscle cells (VSMCs) was completely inhibited by specific ferroptosis inhibitors and an iron chelator. CSE also induced the upregulation of Ptgs2 mRNA, lipid peroxidation, and intracellular GSH depletion, which are key features of ferroptosis. CSE caused medial VSMC loss in ex vivo aortas. These findings demonstrate that ferroptosis is responsible for CSE-induced VSMC death.

Periodontitis-level butyrate-induced ferroptosis in periodontal ligament fibroblasts by activation of ferritinophagy

“…Although NCOA4-mediated ferritinophagy has been implicated in chronic obstructive pulmonary disease, stroke, and ischemia-reperfusion injuries 21 , the molecular mechanisms modulating ferritinophagy and ferroptosis remain obscure. The cigarette smoke induced ferroptosis in bronchial epithelial cells 19,27 and vascular smooth muscle cells 28 , and NCOA4-mediated ferritinophagy promoted ROS accumulation in epithelial cells 27 . Continuous severe cold stress-induced ferroptosisis relied on the apoptosis signal-regulating kinase 1 (ASK1)-p38 MAPK activation 20 , which is also involved in Erastin-induced ferroptosis 29 .…”

NCOA4‐mediated ferritinophagy promoted inflammatory responses in periodontitis

“…Degradation of ferritin releases large quantities of free iron into the labile iron pool, which can trigger excessive intracellular ROS, exhaust pool of cytosolic glutathione, and promote lipid peroxidation 5 . Previously, activation of ferritinophagy has been correlated with cell death of cancer cells, 20,29 and such ferritinophagy‐induced cell death participated in cigarette smoke‐induced chronic obstructive pulmonary diseases, 30‐32 urinary tract infections, 5 and sepsis‐induced cardiac injury 33 . Recent studies showed that ferritinophagy may also play physiological roles in the erythropoiesis in the bone marrow when mice were in iron deficiency, and NCOA4‐knockout mice display microcytosis and mild anemia 8,34 …”

Red Blood Cells and Hemoglobin in Human Atherosclerosis and Related Arterial Diseases

“…It necessitates the entrance into the cell of the Fe +++ /transferrin complex via the transferrin receptor and its reduction in Fe ++ by endosomal ferric reductase at pH 5.2-5.6. It was recently shown that smoking-induced SMC toxicity in the CV system is mediated by ferroptosis [56]. Therefore, both SMCs and endothelial cells could be targets for ferroptosis [57].…”