Full text
| |
| Author(s): |
Anibal Silva de Oliveira
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2017-10-05 |
| Examining board members: |
Eurico de Arruda Neto;
Renato Santana de Aguiar;
Luiz Tadeu Moraes Figueiredo;
Ricardo Luiz Moro de Sousa;
Valeria Valente
|
| Advisor: | Eurico de Arruda Neto |
| Abstract | |
The arbovirus Oropouche (OROV), of the family Peribunyaviridae, genus Orthobunyavirus, is an important cause of febrile disease in Central and South America. Like other Orthobunyaviruses, OROV is enveloped, with a genome comprised of three segments of single-stranded RNA of negative polarity, named according to their sizes as S (small), M (medium) and L (large). The S segment encodes the structural nucleocapsid N protein and, on an alternative reading frame, the NSs nonstructural protein. Although the pathogenesis of OROV is poorly understood, data obtained from murine experimental models indicate that apoptosis plays a central role in killing infected cells. Therefore, while not essential for the replication of OROV, NSs may play important roles in the pathogenesis. Our group has previously demonstrated that OROV induces apoptosis in HeLa cells via the intrinsic pathway, and this effect requires the synthesis of viral proteins. The present study aimed to investigate the role of OROV protein NSs in apoptosis induced in HeLa cells. We found that overexpression of the NSs protein induces apoptosis in different human cell lines (glioblastoma neuroblastoma and human corneal epithelium) 24 hours after transfection. NSs induces apoptosis by the intrinsic pathway, with release of cytochrome c from mitochondria, activation of caspases 9 and 3, and chromatin fragmentation. Interestingly, the NSs protein also induces activation of caspase 8, an element of the extrinsic pathway of apoptosis. An OROV infectious clone lacking the NSs protein (OROVdelNSs) does not induce apoptosis in HeLa cells up to 36 hours postinfection, confirming the importance of the NSs protein for the induction of cell death by apoptosis. The prediction of the structure of the NSs protein revealed the presence of a sequence of thirteen amino acids in the C-terminal region of the protein, which has similarity as a TNF receptor, and this could shed light into a possible mechanism of apoptosis to be validated by experiments silencing target genes in Hela cells. (AU) | |
| FAPESP's process: | 14/02293-8 - Study of apoptosis induced by the Oropouche virus NSs protein |
| Grantee: | Anibal Silva de Oliveira |
| Support Opportunities: | Scholarships in Brazil - Doctorate |