Exocarpium Citri Grandis ameliorates LPS-induced acute lung injury by suppressing inflammation, NLRP3 inflammasome, and ferroptosis

Zaibin Xu; Jiayu Li; Kaili Zhou; Kongyan Wang; Huiyu Hu; Yingjie Hu; Yong Gao; Zhuohui Luo; Jiawen Huang

doi:10.1016/j.jep.2024.118162

Exocarpium Citri Grandis ameliorates LPS-induced acute lung injury by suppressing inflammation, NLRP3 inflammasome, and ferroptosis

J Ethnopharmacol. 2024 Apr 7:329:118162. doi: 10.1016/j.jep.2024.118162. Online ahead of print.

Authors

Zaibin Xu¹, Jiayu Li¹, Kaili Zhou¹, Kongyan Wang¹, Huiyu Hu¹, Yingjie Hu², Yong Gao³, Zhuohui Luo⁴, Jiawen Huang⁵

Affiliations

¹ Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China.
² Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China. Electronic address: yingjiehu@gzucm.edu.cn.
³ Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China. Electronic address: gaoyong@gzucm.edu.cn.
⁴ Research Center for Drug Safety Evaluation of Hainan Province, Hainan Medical University, Haikou, 571199, China; Hainan Pharmaceutical Research and Development Science Park, Haikou, 571199, China. Electronic address: zhuohuiluo@hainmc.edu.cn.
⁵ Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China. Electronic address: huangjiawen@gzucm.edu.cn.

PMID: 38588989
DOI: 10.1016/j.jep.2024.118162

Abstract

Ethnopharmacological relevance: Exocarpium Citri Grandis (ECG), the epicarp of C. grandis 'Tomentosa' which is also known as Hua-Ju-Hong in China, has been widely used for thousands of years to treat inflammatory lung disorders such as asthma, and cough as well as dispelling phlegm. However, its underlying pharmacological mechanisms in acute lung injury (ALI) remain unclear.

Aim of the study: To explore the therapeutic effect of ECG on ALI and reveal the potential mechanisms based on experimental techniques in vivo and in vitro.

Materials and methods: Lipopolysaccharides (LPS) induced ALI in mice and induced RAW 264.7 cell inflammatory model were established to investigate the pharmacodynamics of ECG. ELISA kits, commercial kits, Western Blot, qPCR, Hematoxylin and Eosin (H&E) staining, immunohistochemistry, and immunofluorescence technologies were used to evaluate the pharmacological mechanisms of ECG in ameliorating ALI.

Results: ECG significantly attenuated pulmonary edema in LPS-stimulated mice and decreased the levels of IL1β, IL6, and TNF-α in serum and BALF, reduced MDA and iron concentration as well as increased SOD and GSH levels in lung tissues, and also decreased the ROS level in BALF and Lung tissue. Further pharmacological mechanism studies showed that ECG significantly inhibited mRNA expression of inflammatory signaling factors and chemokines, and down-regulated the expression of TLR4, MyD88, NF-κB p65, NF-κB p-p65 (S536), COX2, iNOS, Txnip, NLRP3, ASC, Caspase-1, JAK1, p-JAK1 (Y1022), JAK2, STAT1, p-STAT1 (S727), STAT3, p-STAT3 (Y705), STAT4, p-STAT4 (Y693), and Keap1, and also up-regulated the expression of Trx-1, Nrf2, HO-1, NQO1, GPX4, PCBP1, and SLC40A1. In the LPS-induced RAW264.7 cell inflammatory model, ECG showed similar results to animal experiments.

Conclusions: Our results showed that ECG alleviated ALI by inhibiting TLR4/MyD88/NF-κB p65 and JAK/STAT signaling pathway-mediated inflammatory response, Txnip/NLRP3 signaling pathway-mediated inflammasome activation, and regulating Nrf2/GPX4 axis-mediated ferroptosis. Our findings provide an experimental basis for the application of ECG.

Keywords: Acute lung injury; Exocarpium Citri Grandis; Ferroptosis; Inflammation; NLRP3 inflammasome.