SARS-CoV-2 ORF7a induces cytotoxicity associated with AP-1 signaling and ferroptosis-related responses
- 1Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- 2Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- 3Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Corresponding author at: Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Abstract
Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), whose accessory proteins have incompletely understood roles in cellular injury. Bioinformatic analysis identified putative N-terminal signal peptides in ORF7a and ORF8. We characterized their expression, subcellular localization, and cytopathic effects in vitro. EGFP-tagged ORF7a and ORF8 showed intracellular ER–Golgi-associated distributions, and untagged ORF7a showed Golgi-associated localization. ORF7a, but not ORF8, induced prominent cytotoxicity in HEK293T cells, as assessed by real-time cell analysis and Annexin V/PI staining. Transcriptomic profiling identified changes in stress-, cell-death-, and ferroptosis-related genes. Ferrostatin-1 attenuated ORF7a-associated cytotoxicity, consistent with ferroptosis-related mechanisms. Mutation of the C-terminal ER retrieval motif (ORF7a-ARA) altered subcellular distribution and attenuated cytotoxicity and cFos/cJun accumulation. The AP-1 inhibitor T-5224 also attenuated cytotoxicity. Additional experiments demonstrated ORF7a localization in A549 cells and extended selected cytotoxicity and inhibitor-response findings to HK-2 cells. In HK-2 cells, ORF7a increased cJun abundance and reduced SLC7A11 and HO-1 protein levels. Together, these findings link the ER retrieval motif to ORF7a-associated cellular injury and support AP-1 involvement and the presence of ferroptosis-related features. Clinical trial number: not applicable.
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BibTeX
@article{chen2026sarscov2,
title = {{SARS-CoV-2 ORF7a induces cytotoxicity associated with AP-1 signaling and ferroptosis-related responses}},
author = {Chia-Hsin Chen and Ru-Fang Li and Yi-Hsiu Wu and Wei-Yu Chen},
journal = {Experimental and Molecular Pathology},
year = {2026},
month = nov,
doi = {10.1016/j.yexmp.2026.105095},
url = {https://doi.org/10.1016/j.yexmp.2026.105095},
note = {CC BY},
}
RIS
TY - JOUR
TI - SARS-CoV-2 ORF7a induces cytotoxicity associated with AP-1 signaling and ferroptosis-related responses
AU - Chia-Hsin Chen
AU - Ru-Fang Li
AU - Yi-Hsiu Wu
AU - Wei-Yu Chen
PY - 2026
DA - 2026/11/04
JO - Experimental and Molecular Pathology
DO - 10.1016/j.yexmp.2026.105095
UR - https://doi.org/10.1016/j.yexmp.2026.105095
AB - Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), whose accessory proteins have incompletely understood roles in cellular injury. Bioinformatic analysis identified putative N-terminal signal peptides in ORF7a and ORF8. We characterized their expression, subcellular localization, and cytopathic effects in vitro. EGFP-tagged ORF7a and ORF8 showed intracellular ER–Golgi-associated distributions, and untagged ORF7a showed Golgi-associated localization. ORF7a, but not ORF8, induced prominent cytotoxicity in HEK293T cells, as assessed by real-time cell analysis and Annexin V/PI staining. Transcriptomic profiling identified changes in stress-, cell-death-, and ferroptosis-related genes. Ferrostatin-1 attenuated ORF7a-associated cytotoxicity, consistent with ferroptosis-related mechanisms. Mutation of the C-terminal ER retrieval motif (ORF7a-ARA) altered subcellular distribution and attenuated cytotoxicity and cFos/cJun accumulation. The AP-1 inhibitor T-5224 also attenuated cytotoxicity. Additional experiments demonstrated ORF7a localization in A549 cells and extended selected cytotoxicity and inhibitor-response findings to HK-2 cells. In HK-2 cells, ORF7a increased cJun abundance and reduced SLC7A11 and HO-1 protein levels. Together, these findings link the ER retrieval motif to ORF7a-associated cellular injury and support AP-1 involvement and the presence of ferroptosis-related features. Clinical trial number: not applicable.
SN - 1096-0945
ER -