Identification of γ-Fagarine as a novel antiviral agent against respiratory virus (hMPV) infection

Jinhua Li; Yao Zhao; Ying Dai; Junning Zhao

doi:10.1016/j.virusres.2023.199223

Identification of γ-Fagarine as a novel antiviral agent against respiratory virus (hMPV) infection

Virus Res. 2023 Oct 15:336:199223. doi: 10.1016/j.virusres.2023.199223. Epub 2023 Sep 23.

Authors

Jinhua Li¹, Yao Zhao², Ying Dai³, Junning Zhao⁴

Affiliations

¹ Department of Pharmacognosy, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
² Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing 400014, China.
³ Translational Chinese Medicine Key Laboratory of Sichuan Province, Sichuan Academy of Chinese Medicine Sciences, Sichuan Institute for Translational Chinese Medicine, Chengdu, Sichuan 610041, China.
⁴ Department of Pharmacognosy, West China School of Pharmacy, Sichuan University, Chengdu 610041, China; National Key Laboratory of Drug Regulatory Science, National Medical Products Administration (NMPA), Beijing 100038, China. Electronic address: zarmy@189.cn.

Abstract

Human metapneumovirus (hMPV) causes significant upper and lower respiratory disease in all age groups worldwide. However, there is no licensed drugs or vaccine available against hMPV. γ-Fagarine, an alkaloid isolated from the root of zanthoxylum, has been reported to be effective in the treatment of cancer, inflammatory diseases and antivirals. However, little is known about the inhibitory effect of γ-Fagarine against respiratory virus infection and the mechanism. In this study, we aim to investigate the effect of γ-Fagarine on hMPV infection and explore its underlying molecular mechanisms. Vero-E6 and 16HBE cells were used as cell models. Virus replication and microcosm character were explored in Vero-E6 cells. Then, the antiviral activities were investigated by quantitative real-time PCR (RT-qPCR), western blotting (WB), and indirect immunofluorescence assays (IFAs) in Vero-E6 and 16HBE. Potential mechanisms of γ-Fagarine related to HSPG and lysosome pH were assessed in 16HBE cells. Lastly, a virus-infected mouse model was established and antiviral assay in vivo was conducted. γ-Fagarine showed no toxicity toward Vero-E6 cells and 16HBE cells but demonstrated anti-hMPV activity. Virus titers of γ-Fagarine group were reduced to 33% and 45% of the hMPV groups, respectively. Besides, mechanistic studies revealed that γ-Fagarine could inhibit hMPV by dual mechanisms of direct restraining virus binding with HSPG and influencing lysosome pH. Furthermore, oral delivery of γ-Fagarine to hMPV-infected mice at a dosage of 25 mg/kg reduced the hMPV load in lung tissues. After γ-Fagarine treatment, pathological damage caused by viral infection was also ameliorated. These findings suggest that γ-Fagarine has antiviral effects in vitro and in vivo, which are associated with its ability to restrain virus binding with HSPG and influence lysosome pH, thus indicating that γ-Fagarine has the potential to serve as a candidate to fight against hMPV infection and other respiratory viruses such as influenza viruses and SARS-CoV-2.

Keywords: Antiviral activity; HSPG; Lysosome; hMPV; γ-Fagarine.