Enoxaparin augments alpha-1-antitrypsin inhibition of TMPRSS2, a promising drug combination against COVID-19 PMID: 35338216

ADC Targets in Oncology

2026-04-10

Enoxaparin augments alpha-1-antitrypsin inhibition of TMPRSS2, a promising drug combination against COVID-19

Sci Rep. 2022 Mar 25;12(1):5207. doi: 10.1038/s41598-022-09133-9.

Xiyuan Bai ^# ¹ ² ³ ⁴ , Ashley M Buckle ^# ⁵ , Eszter K Vladar ⁶ , Edward N Janoff ⁷ ⁸ , Reeti Khare ⁹ , Diane Ordway ¹⁰ , David Beckham ⁸ , Lorelenn B Fornis ¹¹ , Abraham Majluf-Cruz ¹² , Randolph V Fugit ¹³ , Brian M Freed ¹⁴ , Soohyun Kim ¹⁵ ¹⁶ , Robert A Sandhaus ¹¹ , Edward D Chan ¹⁷ ¹⁸ ¹⁹ ²⁰

Affiliations

1. Department of Medicine, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, USA. [email protected].
2. Department of Academic Affairs and Medicine, National Jewish Health, Denver, CO, USA. [email protected].
3. Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA. [email protected].
4. National Jewish Health, D509, Neustadt Building, 1400 Jackson Street, Denver, CO, 80206, USA. [email protected].
5. Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.
6. Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
7. Department of Medicine, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, USA.
8. Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
9. Mycobacteriology Laboratory, Advance Diagnostics, National Jewish Health, Denver, CO, USA.
10. Department of Microbiology, Immunlogy, and Pathology, Colorado State University, Fort Collins, CO, USA.
11. Department of Academic Affairs and Medicine, National Jewish Health, Denver, CO, USA.
12. Unidad de Investigacion Medica en Trombosis, Hemostasia y Aterogenesis, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
13. Department of Pharmacy, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, USA.
14. Department of Immunology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
15. Laboratory of Cytokine Immunology, Department of Biomedical Science and Technology, Konkuk University, Seoul, South Korea.
16. College of Veterinary Medicine, Konkuk University, Seoul, South Korea.
17. Department of Medicine, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, USA. [email protected].
18. Department of Academic Affairs and Medicine, National Jewish Health, Denver, CO, USA. [email protected].
19. Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA. [email protected].
20. National Jewish Health, D509, Neustadt Building, 1400 Jackson Street, Denver, CO, 80206, USA. [email protected].
# Contributed equally.

Abstract

The cell surface serine protease Transmembrane Protease 2 (TMPRSS2) is required to cleave the spike protein of SARS-CoV-2 for viral entry into cells. We determined whether negatively-charged heparin enhanced TMPRSS2 inhibition by alpha-1-antitrypsin (AAT). TMPRSS2 activity was determined in HEK293T cells overexpressing TMPRSS2. We quantified Infection of primary human airway epithelial cells (hAEc) with human coronavirus 229E (HCoV-229E) by immunostaining for the nucleocapsid protein and by the plaque assay. Detailed molecular modeling was undertaken with the heparin-TMPRSS2-AAT ternary complex. Enoxaparin enhanced AAT inhibition of both TMPRSS2 activity and Infection of hAEc with HCoV-229E. Underlying these findings, detailed molecular modeling revealed that: (i) the reactive center loop of AAT adopts an inhibitory-competent conformation compared with the crystal structure of TMPRSS2 bound to an exogenous (nafamostat) or endogenous (HAI-2) TMPRSS2 inhibitor and (ii) negatively-charged heparin bridges adjacent electropositive patches at the TMPRSS2-AAT interface, neutralizing otherwise repulsive forces. In conclusion, enoxaparin enhances AAT inhibition of both TMPRSS2 and coronavirus Infection. Such host-directed therapy is less likely to be affected by SARS-CoV-2 mutations. Furthermore, given the known anti-inflammatory activities of both AAT and heparin, this form of treatment may target both the virus and the excessive inflammatory consequences of severe COVID-19.