Mosquito Small RNA Responses to West Nile and Insect-Specific Virus Infections in Aedes and Culex Mosquito Cells

• Published in: Viruses Vol. 11; no. 3; p. 271
• Main Authors: Göertz, Giel P, Miesen, Pascal, Overheul, Gijs J, van Rij, Ronald P, van Oers, Monique M, Pijlman, Gorben P
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18-03-2019; MDPI
• Subjects: Aedes - genetics; Aedes - virology; Aedes aegypti; Animals; Arthropods; Bias; Cell culture; Cell Line; Cell lines; Cloning; Culex; Culex - genetics; Culex - virology; Culicidae; de novo assembly; Double-stranded RNA; Genes; Genome, Insect; High-Throughput Nucleotide Sequencing; Infections; insect-specific viruses; Insects; mosquito cells; Mosquito Vectors - genetics; Mosquito Vectors - virology; Mosquitoes; next-generation sequencing; PIWI-interacting RNAs; Proteins; RNA - blood; RNA Interference; RNA viruses; RNA Viruses - physiology; RNA, Double-Stranded; RNAi; Sequence Analysis, RNA; siRNA; small RNA; small-interfering RNAs; Tropical diseases; virus discovery; Viruses; West Nile virus; United States > US; RNAi; next-generation sequencing; West Nile virus; small-interfering RNAs; insect-specific viruses; virus discovery; PIWI-interacting RNAs; mosquito cells; de novo assembly; small RNA
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v11030271

Small RNA mediated responses are essential for antiviral defence in mosquitoes, however, they appear to differ per virus-vector combination. To further investigate the diversity of small RNA responses against viruses in mosquitoes, we applied a small RNA deep sequencing approach on five mosquito cell lines:
CT cells,
U4.4 and C6/36 cells,
Aag2 cells (cleared from cell fusing agent virus and Culex Y virus (CYV) by repetitive dsRNA transfections) and
AP-61 cells.
assembly of small RNAs revealed the presence of Phasi Charoen-like virus (PCLV), Calbertado virus, Flock House virus and a novel narnavirus in CT cells, CYV in U4.4 cells, and PCLV in Aag2 cells, whereas no insect-specific viruses (ISVs) were detected in C6/36 and AP-61 cells. Next, we investigated the small RNA responses to the identified ISVs and to acute infection with the arthropod-borne West Nile virus (WNV). We demonstrate that AP-61 and C6/36 cells do not produce siRNAs to WNV infection, suggesting that AP-61, like C6/36, are Dicer-2 deficient. CT cells produced a strong siRNA response to the persistent ISVs and acute WNV infection. Interestingly, CT cells also produced viral PIWI-interacting (pi)RNAs to PCLV, but not to WNV or any of the other ISVs. In contrast, in U4.4 and Aag2 cells, WNV siRNAs, and pi-like RNAs without typical ping-pong piRNA signature were observed, while this signature was present in PCLV piRNAs in Aag2 cells. Together, our results demonstrate that mosquito small RNA responses are strongly dependent on both the mosquito cell type and/or the mosquito species and family of the infecting virus.