Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Jul 7:e30627.
doi: 10.1002/jcb.30627. Online ahead of print.

SARS-CoV-2 Spike Protein Induces Time-Dependent CTSL Upregulation in HeLa Cells and Alveolarspheres

Magdalena M Bolsinger  1 , Alice Drobny  1 , Sibylle Wilfling  2 , Stephanie Reischl  3 , Florian Krach  3 , Raul Moritz  1 , Denise Balta  1 , Ute Hehr  2 , Elisabeth Sock  4 , Florian Bleibaum  5 , Frank Hanses  6   7 , Beate Winner  3 , Susy Prieto Huarcaya  1 , Philipp Arnold  8 , Friederike Zunke  1
Affiliations

SARS-CoV-2 Spike Protein Induces Time-Dependent CTSL Upregulation in HeLa Cells and Alveolarspheres

Magdalena M Bolsinger et al. J Cell Biochem. .

Abstract

Autophagy and lysosomal pathways are involved in the cell entry of SARS-CoV-2 virus. To infect the host cell, the spike protein of SARS-CoV-2 binds to the cell surface receptor angiotensin-converting enzyme 2 (ACE2). To allow the fusion of the viral envelope with the host cell membrane, the spike protein has to be cleaved. One possible mechanism is the endocytosis of the SARS-CoV-2-ACE2 complex and subsequent cleavage of the spike protein, mainly by the lysosomal protease cathepsin L. However, detailed molecular and dynamic insights into the role of cathepsin L in viral cell entry remain elusive. To address this, HeLa cells and iPSC-derived alveolarspheres were treated with recombinant SARS-CoV-2 spike protein, and the changes in mRNA and protein levels of cathepsins L, B, and D were monitored. Additionally, we studied the effect of cathepsin L deficiency on spike protein internalization and investigated the influence of the spike protein on cathepsin L promoters in vitro. Furthermore, we analyzed variants in the genes coding for cathepsin L, B, D, and ACE2 possibly associated with disease progression using data from Regeneron's COVID Results Browser and our own cohort of 173 patients with COVID-19, exhibiting a variant of ACE2 showing significant association with COVID-19 disease progression. Our in vitro studies revealed a significant increase in cathepsin L mRNA and protein levels following exposure to the SARS-CoV-2 spike protein in HeLa cells, accompanied by elevated mRNA levels of cathepsin B and D in alveolarspheres. Moreover, an increase in cathepsin L promoter activity was detected in vitro upon spike protein treatment. Notably, the knockout of cathepsin L resulted in reduced internalization of the spike protein. The study highlights the importance of cathepsin L and lysosomal proteases in the SARS-CoV-2 spike protein internalization and suggests the potential of lysosomal proteases as possible therapeutic targets against COVID-19 and other viral infections.

Keywords: SARS‐CoV‐2; cathepsin L; cathepsins; lysosomes; spike protein.

PubMed Disclaimer

Similar articles

See all similar articles

References

    1. I. Mellman, “Organelles Observed: Lysosomes,” Science (New York, NY) 244, no. 4906 (1989): 853–854.
    1. C. Settembre, A. Fraldi, D. L. Medina, and A. Ballabio, “Signals from the Lysosome: A Control Centre for Cellular Clearance and Energy Metabolism,” Nature Reviews Molecular Cell Biology 14, no. 5 (2013): 283–296.
    1. J. W. Coffey and C. de Duve, “Digestive Activity of Lysosomes,” Journal of Biological Chemistry 243, no. 12 (1968): 3255–3263.
    1. A. M. Cuervo and J. F. Dice, “A Receptor for the Selective Uptake and Degradation of Proteins by Lysosomes,” Science 273, no. 5274 (1996): 501–503.
    1. S. Ohkuma, and B. Poole, “Fluorescence Probe Measurement of the Intralysosomal pH in Living Cells and the Perturbation of pH by Various Agents,” Proceedings of the National Academy of Sciences of the United States of America 75, no. 7 (1978): 3327–3331.

LinkOut - more resources