[Source: Antiviral Research, full page: (LINK). Abstract, edited.]
Antiviral Research | Available online 20 July 2020, 104885 | In Press, Journal Pre-proof
14-Deoxy-11,12-didehydroandrographolide inhibits apoptosis in influenza A(H5N1) virus-infected human lung epithelial cells via the caspase-9-dependent intrinsic apoptotic pathway which contributes to its antiviral activity
Wentao Cai a, Haimei Wen a, Qinyang Zhou a, Lei Wu a, Yong Chen a, Hongbo Zhou b, Meilin Jin b
a Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China; b State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, The Cooperative Innovation Center for Sustainable Pig Production, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
Received 6 March 2020, Revised 26 May 2020, Accepted 22 June 2020, Available online 20 July 2020.
- DAP inhibits caspase-3 and caspase-9 activation induced by influenza A(H5N1) virus in vitro.
- DAP reduces mitochondrial membrane potential loss and represses cytochrome crelease.
- DAP exerts anti-apoptotic effect via the caspase-9-dependent intrinsic pathway.
- Anti-H5N1 ability of DAP partly depends on the inhibition of caspase-9 activity.
- We propose that DAP is a potential candidate of anti-influenza drug.
Influenza A virus (IAV) infection represents a global health challenge. Excavating antiviral active components from traditional Chinese medicine (TCM) is a promising anti-IAV strategy. Our previous studies have demonstrated that 14-deoxy-11,12-didehydroandrographolide (DAP), a major ingredient of a TCM herb called Andrographis paniculata, shows anti-IAV activity that is mainly effective against A/chicken/Hubei/327/2004 (H5N1), A/duck/Hubei/XN/2007 (H5N1), and A/PR/8/34 (H1N1) in vitro and in vivo. However, the underlying anti-IAV molecular mechanism of DAP needs further investigation. In the present work, we found that DAP can significantly inhibit the apoptosis of human lung epithelial (A549) cells infected with A/chicken/Hubei/327/2004 (H5N1). After DAP treatment, the protein expression levels of cleaved PARP, cleaved caspase-3, and cleaved caspase-9, and the activities of caspase-3 and caspase-9 in H5N1-infected A549 cells were all obviously downregulated. However, DAP had no inhibitory effect on caspase-8 activity and cleaved caspase-8 production. Meanwhile, the efficacy of DAP in reducing the apoptotic cells was lost after using the inhibitor of caspase-3 or caspase-9 but remained intact after the caspase-8 inhibitor treatment. Moreover, DAP efficiently attenuated the dissipation of mitochondrial membrane potential, suppressed cytochrome c release from the mitochondria to the cytosol, and decreased the protein expression ratio of Bax/Bcl-2 in the mitochondrial fraction. Furthermore, the silencing of caspase-9 reduced the yield of nucleoprotein (NP) and disabled the inhibitory ability of DAP in NP production in A549 cells. Overall results suggest that DAP exerts its antiviral effects by inhibiting H5N1-induced apoptosis on the caspase-9-dependent intrinsic/mitochondrial pathway, which may be one of the anti-H5N1 mechanisms of DAP.
© 2020 Elsevier B.V. All rights reserved.
Keywords: A/H5N1; Avian Influenza; Antivirals.