Synergistic activation of bat SARS-like coronaviruses spike protein by elastase and TMPRSS2

• Published in: Scientific reports Vol. 15; no. 1; pp. 26469 - 16
• Main Authors: Yamamoto, Yuichiro, Inoue, Tetsuya, Sugiyama, Naoto, Furukawa, Miyu, Sato, Kaoru, Onodera, Taishi, Takahashi, Yoshimasa, Wakita, Takaji, Fukasawa, Masayoshi, Noguchi, Kohji
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21.07.2025; Nature Publishing Group; Nature Portfolio
• Subjects: 631/326; 631/337; ACE2; Amino acids; Angiotensin-converting enzyme 2; Animals; Bat SARS-like coronavirus; Benzamidines - pharmacology; Cells; Chiroptera - virology; Chlorocebus aethiops; Coronaviridae; Coronaviruses; COVID-19; Disease transmission; Elastase; Epidemics; Experiments; Guanidines; Humanities and Social Sciences; Humans; Infections; Infectivity; Inflammation; Khosta-2; Medical research; Middle East respiratory syndrome; multidisciplinary; Pancreatic Elastase - metabolism; Proteases; Proteins; Proteolysis; RaTG13; Respiratory diseases; Sarbecovirus; Science; Science (multidisciplinary); Serine Endopeptidases - metabolism; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Severe acute respiratory syndrome-related coronavirus - metabolism; Spike Glycoprotein, Coronavirus - genetics; Spike Glycoprotein, Coronavirus - metabolism; Spike protein; Statistical analysis; Thermolysin; Trypsin; Vero Cells; Virus Internalization; Viruses; Zoonoses; Bat SARS-like coronavirus; Elastase; Spike protein; Khosta-2; RaTG13
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-025-11600-y

Although numerous sarbecoviruses have been identified in bats, but most lack the ability to infect human cells. Some barriers limit coronavirus zoonosis, including susceptibility to host proteases. Here, we investigated whether exogenous protease treatment can circumvent host restrictions in two severe acute respiratory syndrome (SARS)-related bat coronaviruses. We found that the spike proteins of RaTG13 and Khosta-2, which are sarbecoviruses obtained from horseshoe bats in China and Russia, respectively, facilitated the ACE2-mediated entry of pseudotyped viruses into VeroE6/TMPRSS2 cells following elastase treatment. In contrast, trypsin and thermolysin exhibited no effects. Elastase-enhanced infectivity correlated with increased fusogenicity driven by the cleavage of spike proteins. This process was TMPRSS2-dependent and was inhibited by nafamostat, a TMPRSS2 inhibitor. Additionally, mutation of residue 809 within the S2 subunit of the RaTG13 spike protein (S809D) impaired elastase-induced cleavage and infectivity. Hence, proteolytic processing of the spike protein serves as a restriction to RaTG13 and Khosta-2 infections, which can be overcome by elastase. This suggests that elastase secreted in inflamed tissues during viral infection may increase the zoonotic potential of sarbecoviruses by facilitating human cell entry.