Human testicular organoid system as a novel tool to study Zika virus pathogenesis
Saguna Verma1, Daniel P. Strange1, Nima P. Zarandi2, Goral Trivedi1, and Hooman Sadri-Ardekani2,3,
1Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI; 2Wake Forest Institute for Regenerative Medicine (WFIRM); 3Department of Urology, Wake Forest School of Medicine, Winston Salem, NC
Zika virus (ZIKV) is an arbovirus belonging to the Flavivirus genus of the Flaviviridae family. The 2015-16 ZIKV epidemic in South America resulted in more than 1.5 million symptomatic cases. Traditionally associated with mild fever, the recent outbreak presented new severe features of ZIKV disease, including neonatal microcephaly and Guillain-Barre syndrome in adults. Further, sexual transmission of ZIKV emerged as a cause of disease spread to non-endemic regions, a unique finding not reported for other flaviviruses. ZIKV has been detected in semen for up to 188 days after symptoms onset and is shown to potentially affect fertility, indicating ZIKV establishes persistence in the testes. Our recent study demonstrated that ZIKV could efficiently infect human Sertoli cells, an important cell type that contributes to the immune privilege environment of seminiferous tubules. However, due to lack of relevant animal models to study ZIKV pathogenesis and apparent limitations of monolayer cultures, an in vitro system that incorporates multiple human testicular cell types to partially recapitulate testis function is needed to investigate pathogenic features of ZIKV infection in the human testes. Our recently developed a human testicular organoid (hTO) model consists of multiple testicular cell types, that produces testosterone continuously and partially supports early stages of spermatogenesis. These hTOs were infected with an epidemic ZIKV strain and then subsequently assessed for virus replication, viability, and function post-infection. Our data shows that hTO supported productive ZIKV replication over 21 days of infection, which resulted in reduced survival and function. Our results also demonstrated induction of transcripts of key antiviral genes including type I Interferon and cytokines IL-6 following ZIKV infection. Collectively, our results indicate that hTO can be used as a relevant model to study ZIKV pathogenesis, including cellular targets, immune response, and potential effects on spermatogenesis.