Electroacupuncture Alleviates LPS-Induced ARDS Through α7 Nicotinic Acetylcholine Receptor-Mediated Inhibition of Ferroptosis

Abstract

Acute respiratory distress syndrome (ARDS) is an uncontrollable, progressive pulmonary inflammatory disease, and as a common clinical critical disease, there is no effective treatment available. Electroacupuncture (EA) therapy is a type of traditional Chinese medicine physiotherapy that can alleviate the inflammatory response. However, the potential mechanism of EA in the treatment of ARDS is not yet clear. Ferroptosis is a new type of programmed cell death characterized by intracellular iron accumulation and lipid peroxidation. Recently, emerging evidence has shown that ferroptosis is closely related to the occurrence and development of ARDS caused by various pathological factors. Here, we further investigated whether EA-mediated inhibition of ferroptosis in lung tissue could attenuate lipopolysaccharide (LPS)-induced ARDS and explored its underlying mechanisms. In this study, mice were administered LPS intraperitoneally to establish a model of LPS-induced ARDS. We found that EA stimulation could not only reduce the exudation of inflammatory cells and proteins in the alveolar lumen but also significantly alleviate the pathological changes of lung tissue, inhibit the production of proinflammatory cytokines and improve the survival rate of mice. Concurrently, we also found that ferroptosis events occurred in the lung tissue of LPS-induced ARDS mice, manifested by elevated iron levels, ROS production and lipid peroxidation. Intriguingly, our results showed that EA stimulation at the Zusanli (ST36) acupoint activated α7 nicotinic acetylcholine receptor (α7nAchR) in lung tissue mainly through the sciatic nerve and cervical vagus nerve, thus exerting anti-ferroptosis and pulmonary protective effects. Additionally, these effects were eliminated by methyllycaconitine (MLA), a selective antagonist of α7nAchR. In vitro experiments, activation of α7nAchR protected alveolar epithelial cells from LPS-induced ferroptosis. Furthermore, our experiments showed that the pulmonary protective effects of EA stimulation were effectively reversed by erastin, a ferroptosis activator. Collectively, we demonstrated that EA stimulation could alleviate LPS-induced ARDS by activating α7nAchR to inhibit LPS-induced ferroptosis in alveolar epithelial cells. Targeting and regulating ferroptosis in alveolar epithelial cells may be a potential intervention approach for the treatment of LPS-induced ALI/ARDS in the future.

Detection of melatonin protective effects in sepsis via argyrophilic nucleolar regulatory region‐associated protein synthesis and TLR4/NF‐κB signaling pathway

“…In addition, melatonin has antioxidant and antiapoptotic effects. Studies have mentioned the antioxidant properties of melatonin (Favero et al, 2017; Majidinia et al, 2018; Zhang et al, 2022).…”

Ferroptosis increases obesity: Crosstalk between adipocytes and the neuroimmune system

“…For example, in acute respiratory distress, ferroptosis has been found in mouse lung tissue, together with iron accumulation, increased ROS, and lipid peroxidation ( 103 ). The use of electro-acupuncture to stimulate the Zusanli (ST36) acupoint can activate the α7 nicotinic acetylcholine receptor in the lung tissue through the cervical vagus nerve and sciatic nerve to protect the ferroptosis in the lung tissue, which also verifies the importance of the vagus nerve in protecting the oxidative damage of cells ( 104 ) ( Figure 2 ). The vagus nerve can also inhibit the release of pro-inflammatory cytokines in such a way that mediates selective cholinergic activation in the inflammatory response, thereby improving inflammation and obesity ( 97 , 98 , 105 ).…”

Ferroptosis, pyroptosis and necroptosis in acute respiratory distress syndrome

“…However, it remains to be uncovered how NRF2-mediated ferroptosis protects ARDS by regulating iron and how those pathways converge with iron proteins such as FTL or FTH1. In addition to the NRF2 pathway, recent studies have proven that activating the α7 nicotinic acetylcholine receptor (α7nAchR) in lung tissue [64] or blocking mTOR signaling [65] can significantly ameliorate the sepsis-induced ARDS by inhibiting ferroptosis. The expression of GPX4 and SLC7A11 increased and the iron level decreased.…”