Cathepsin B & L are not required for ebola virus replication

Area of Science:

• Virology
• Molecular Biology
• Pathogen Research

Background:

• Ebola virus (EBOV), a filovirus, causes severe hemorrhagic fever with high fatality rates.
• The viral glycoprotein (GP) is crucial for EBOV entry and pathogenicity.
• Endosomal acidification activates cysteine proteases Cathepsin B (CatB) and L (CatL), which cleave EBOV GP, facilitating viral entry.

Purpose of the Study:

• To investigate the role of Cathepsin B (CatB) and Cathepsin L (CatL) in the in vitro and in vivo replication of Ebola virus (EBOV).

Main Methods:

• Studied the effect of CatB and CatL on EBOV entry into cultured cells using various EBOV species.
• Assessed EBOV replication in vitro.
• Utilized a mouse model to evaluate EBOV infection in wild-type, catB(-/-), and catL(-/-) mice.

Main Results:

• CatB, but not CatL, influenced ZEBOV entry into cultured cells.
• Entry of other EBOV species and general EBOV replication were independent of CatB and CatL.
• In vivo, catB(-/-) and catL(-/-) mice showed no difference in susceptibility, viral replication, or survival upon lethal ZEBOV challenge compared to wild-type mice.

Conclusions:

• Cathepsin B and L activity are not essential for Ebola virus replication.
• EBOV glycoprotein cleavage is likely mediated by multiple proteases, hindering the development of targeted therapies.