Proteomic Analysis Identifies the Glutathione Synthesizing Enzyme Gclc as an Andrographolide Target and a Protective Factor Against Sars-Cov-2 Infection

Abstract

Even though advanced progresses have been made for COVID-19 vaccines, rapid and extensive mutations of the SARS-CoV-2 genomes have provided a selective advantage for the virus to escape the adaptive immunity leading to a critical challenge for current treatments and preventions of COVID-19. We report here the antiviral activity of andrographolide against SARS-CoV-2 wildtype and Omicron variants. Proteomic analysis was employed to identify cellular pathways and key proteins controlled by andrographolide in the human lung epithelial cells Calu-3 infected by SARS-CoV-2. Gene ontology analysis indicates that proteins involved in NRF2-regulated pathways are differentially expressed by andrographolide. Notably, andrographolide increases expression and nuclear localization of the transcription factor NRF2. In addition, transcriptional expression of GCLC and GCLM, which are NRF2 target genes, are induced by andrographolide. We further find that infection of SARS-CoV-2 results in a reduction of glutathione level in Calu-3; the effect that is rescued by andrographolide. Moreover, andrographolide also induces expression of the glutathione producing enzyme GCLC in SARS-CoV-2 infected lung epithelial cells. Importantly, an ectopic over-expression of GCLC or treatment of N-acetylcysteine in Calu-3 cells led to a decrease in SARS-CoV-2 infection. Collectively, our findings suggest the interplay between GCLC-mediated glutathione biogenesis induced by andrographolide and the anti-SARS-CoV-2 activity. The glutathione biogenesis and recycling pathways should be further exploited as a targeted therapy against SARS-CoV-2 infection.

Note:
Funding Information: This research project was supported by CIF Grant, Faculty of Science, Mahidol University. J.C. was supported by Science Achievement Scholarship of Thailand. A.T. was supported by Abhaiphubet Chaopraya Hospital Foundation. P.W. was supported by Fundamental Fund, Mahidol University (FF66; FF-067/2566); National Research Council of Thailand (NRCT; N35A650053); and Program Management Unit for Human Resources and Institutional Development, Research and Innovation (PMU-B; B05F640047); and Mahidol University (Reinventing University grant).

Declaration of Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Keywords: andrographolide, GCLC, Glutathione, SARS-CoV-2