Novel Potent Autophagy Inhibitor Ka-003 Inhibits Dengue Virus Replication

Abstract

Every year, dengue virus (DENV) affects millions of people. Currently, there are no approved drugs for the treatment of DENV infection. Autophagy is a conserved degradation process that was shown to be induced by DENV infection and required for optimal DENV replication. The modulation of autophagy is, therefore, considered an attractive target to treat DENV infection. This study carried out a high-content image screen analysis using Crispr-Cas9 GFP-LC3 knocked-in HeLa cells of a compound library synthesized from or inspired by natural products and their biocongener precursors to discover novel autophagy inhibitors. The screen identified Ka-003 as the most effective compound for decreasing the number of autophagic vacuoles inside cells upon autophagy induction. Ka-003 could inhibit autophagy in a dose-dependent manner at low micromolar concentrations. More importantly, Ka-003 demonstrated the concentration-dependent inhibition of DENV production in Crispr-Cas9 GFP-LC3 knocked-in THP-1 monocytes. The core structure of Ka-003, which is a methyl cyclohexene derivative, resembles those found in mulberry plants, and could be synthetically prepared in a bioinspired fashion. Taken together, data indicate that Ka-003 hampered autophagy and limited DENV replication. The low cytotoxicity of Ka-003 suggests its therapeutic potential, which warrants further studies for the lead optimization of the compound for dengue treatment.

Hijacking autophagy for infection by flaviviruses

“…NS1 also serves as a platform for LKB and LKB1 to interact with each other, recruiting them together to form a complex, thereby inducing autophagy ( Wu et al, 2023 ). Ka-003, a lysosomal fusion inhibitor, hampers autophagy, and thus limits DENV replication, implying a key role for lysosome fusion in the DENV-3 life cycle ( Limthongkul et al, 2023 ). Studies also found that autophagy not only provides a replication platform for DENV, but also assists its transmission by evading antibody neutralization ( Acharya et al, 2019 ).…”