Anemoside B4 protects against Klebsiella pneumoniae- and influenza virus FM1-induced pneumonia via the TLR4/Myd88 signaling pathway in mice

Jia He; Renyikun Yuan; Xiaolan Cui; Yushun Cui; Shan Han; Qin-Qin Wang; Yangling Chen; Liting Huang; Shilin Yang; Qiongming Xu; Yonghui Zhao; Hongwei Gao

doi:10.1186/s13020-020-00350-w

Anemoside B4 protects against Klebsiella pneumoniae- and influenza virus FM1-induced pneumonia via the TLR4/Myd88 signaling pathway in mice

Chin Med. 2020 Jul 2:15:68. doi: 10.1186/s13020-020-00350-w. eCollection 2020.

Authors

Jia He^{1

2}, Renyikun Yuan^{1

3}, Xiaolan Cui⁴, Yushun Cui³, Shan Han^{1

2}, Qin-Qin Wang^{1

2}, Yangling Chen^{1

2}, Liting Huang^{1

2}, Shilin Yang^{1

2}, Qiongming Xu^{1

5}, Yonghui Zhao⁶, Hongwei Gao^{1

2}

Affiliations

¹ College of Pharmacy, Guangxi University of Chinese Medicine, Nanning, 530000 China.
² Guangxi Engineering Technology Research Center of Advantage Chinese Patent Drug and Ethnic Drug Development, Nanning, 530020 China.
³ Jiangxi University of Traditional Chinese Medicine, Nanchang, 330004 China.
⁴ Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700 China.
⁵ College of Pharmaceutical Science, Soochow University, Suzhou, 215123 China.
⁶ Qingdao Central Hospital, The Second Affiliated Hospital of Qingdao University, Qingdao, 266109 China.

Abstract

Background: Pneumonia refers to the inflammation of the terminal airway, alveoli and pulmonary interstitium, which can be caused by pathogenic microorganisms, physical and chemical factors, immune damage, and drugs. Anemoside B4, the major ingredient of Pulsatilla chinensis (Bunge) Regel, exhibited anti-inflammatory activity. However, the therapeutic effect of anemoside B4 on pneumonia has not been unraveled. This study aims to investigate that anemoside B4 attenuates the inflammatory responses in Klebsiella pneumonia (KP)- and influenza virus FM1 (FM1)-induced pneumonia mice model.

Methods: The network pharmacology and molecular docking assays were employed to predict the targets of anemoside B4's treatment of pneumonia. Two models (bacterial KP-infected mice and virus FM1-infected mice) were employed in our study. BALB/c mice were divided into six groups: control, model group (KP-induced pneumonia or FM1-induced pneumonia), anemoside B4 (B4)-treated group (2.5, 5, 10 mg/kg), and positive drug group (ribavirin or ceftriaxone sodium injection). Blood samples were collected for hematology analysis. The effects of B4 on inflammation-associated mediators were investigated by Enzyme-linked immunosorbent assay (ELISA) and hematoxylin and eosin staining (HE) staining. Proteins expression was quantified by western blotting.

Results: The network results indicated that many pro-inflammatory cytokines such as tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) participated in anemoside B4's anti-inflammatory activity. The counts of neutrophil (NEU) and white blood cell (WBC), the level of myeloperoxidase (MPO), and the release of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 increased by KP or FM1 infection, which were reversed by anemoside B4. In addition, anemoside B4 significantly suppressed the FM1-induced expression of toll-like receptor 4 (TLR4), myeloid differential protein-88 (MyD88), and myeloid differentiation protein-2 (MD-2), which were further validated by molecular docking data that anemoside B4 bound to bioactive sites of TLR4. Therefore, anemoside B4 exhibited a significant therapeutic effect on pneumonia via the TLR4/MyD88 pathway.

Conclusion: Our findings demonstrated that anemoside B4 attenuates pneumonia via the TLR4/Myd88 signaling pathway, suggesting that anemoside B4 is a promising therapeutic candidate for bacterial-infected or viral-infected pneumonia.

Keywords: Anemoside B4; Influenza virus FM1; Klebsiella pneumoniae; Pneumonia; TLR4/Myd88.