Bis-benzylisoquinoline alkaloids inhibit flavivirus entry and replication by compromising endolysosomal trafficking and autophagy
Lihong Huang, Lele Liu, Junhai Zhu, Nanjun Chen, Jie Chen, Chuen-Fuk Chan, Fei Gao, You-Qin Yin, Jiufeng Sun, Rongxin Zhang, Kehui Zhang, Wenbao Qi, Jianbo Yue
Abstract
Flaviviruses, such as dengue virus (DENV), Zika virus (ZIKV), and Japanese encephalitis virus (JEV), represent a substantial public health challenge as there are currently no approved treatments available. Here, we investigated the antiviral effects of bis-benzylisoquinoline alkaloids (BBAs) on flavivirus infections. We evaluated five specific BBAs—berbamine, tetrandrine, iso-tetrandrine, fangchinoline, and cepharanthine—and found that they effectively inhibited infections by ZIKV, DENV, or JEV by blocking virus entry and genome replication stages in the flavivirus life cycle. Furthermore, we synthesized a fluorophore-conjugated BBA and showed that BBAs targeted endolysosomes, causing lysosomal pH alkalization. Mechanistic studies on inhibiting ZIKV infection by BBAs revealed that these compounds blocked TRPML channels, leading to lysosomal dysfunction and reducing the expression of NCAM1, a key receptor for the entry of ZIKV into cells, thereby decreasing cells susceptibility to ZIKV infection. Additionally, BBAs inhibited the fusion of autophagosomes and lysosomes, significantly reducing viral RNA replication. Collectively, our results suggest that BBAs inhibit flavivirus entry and replication by compromising endolysosomal trafficking and autophagy, respectively, underscoring the potential of BBAs as therapeutic agents against flavivirus infections. • Five specific benzylisoquinoline alkaloids (BBAs) inhibit ZIKV, DENV, and JEV infections. • BBAs target endolysosomes, leading to an increase in lysosomal pH. • BBAs inhibit TRPML channels, leading to lysosomal dysfunction and a significant reduction in the entry of ZIKV into cells. • BBAs impaire viral RNA replication by inhibiting the fusion of autophagosomes and lysosomes.