Biology subjects

Rossi, A. D.

Publications and source records attributed to Rossi, A. D..

3 recordsLinked to original sources

bioRxiv2025

Mutational spectra reveal influenza virus transmission routes and adaptation

Influenza A virus remains a major cause of morbidity and mortality in humans and animals with pandemic potential. While control of outbreaks and spillover events remains a key health priority, the transmission routes and adaptations causing these episodes remain unclear. To understand these processes, we compared mutational spectra across the complete diversity of influenza A virus. We find that niche-specific mutagens cause large convergent shifts in mutational spectrum between gastrointestinal and respiratory lineages, allowing inference of transmission route and site of infection, while additional mutational patterns are host-specific, permitting detection of species responsible for outbreaks. By identifying points of spectrum change in phylogenetic trees, we discover novel adaptive mutations enabling sustained respiratory transmission. We conclude that mutational spectra can enable early detection of lineages with increased potential for spillover and onward transmission, and should be considered as a component of genomic surveillance strategies.

microbiology↗

bioRxiv2021

Zika virus infection during development impairs the formation of corpus callosum by disturbing axon guidance and growth of callosal neurons.

Congenital Zika Syndrome (CZS) is a set of birth defects caused by Zika virus (ZIKV) infection during pregnancy. Microcephaly is its main feature, but other brain abnormalities are found in CZS patients, such as ventriculomegaly, brain calcifications, and dysgenesis of the corpus callosum. Many studies have focused on microcephaly, but it remains unknown how ZIKV infection leads to callosal malformation. To tackle this issue, we infected mouse embryos in utero with a Brazilian ZIKV isolate and found that they are born with a reduction in callosal area and density of callosal neurons. ZIKV infection also causes a density reduction of PH3+ cells, intermediate progenitor cells and SATB2+ neurons. Moreover, axonal tracing revealed that callosal axons are reduced and misrouted. Also, ZIKV infected cultures show a reduction of callosal axon length. GFAP labelling showed that in utero infection compromises glial cells responsible for midline axon guidance. The RNA-Seq data from infected brains identified downregulation of axon guidance and axonogenesis related genes. In sum, we showed that ZIKV infection impairs critical steps of corpus callosum formation by disrupting not only neurogenesis but also axon guidance and growth across the midline. Summary StatementZika virus infection during development impairs the formation of corpus callosum by disturbing axon guidance and growth of callosal neurons.

neuroscience↗

bioRxiv2018

Reactivation of latent HIV-1 in vitro using an alcoholic extract from Euphorbia umbellata (Euphorbiaceae) latex.

Euphorbia umbellata (E. umbellata) belongs to Euphorbiaceae family, popularly known as Janauba, and contains in its latex a combination of phorbol esters with biological activities described to different cellular protein kinase C (PKC) isoforms. Here, we identified deoxi-phorbol esters present in E. umbellata latex alcoholic extract able to increase HIV transcription and reactivate HIV from latency models. This activity was mediated by NF-kB activation followed by nuclear translocation and binding to HIV LTR promoter. In addition, E. umbellate latex extract induced the production of pro inflammatory cytokines together with IL21 in in vitro human PBMC cultures. Our latex extract activates latent HIV in human PBMCs isolated from HIV positive patients as well as latent SIV in non-human primate primary CD4+ T lymphocytes. These results strongly indicate that the phorbol esters present in E. umbellata latex are promising candidate compounds for future clinical trials for shock and kill therapy to promote HIV cure and eradication.

microbiology↗