Neural Infection by Oropouche Virus in Adult Human Brain Slices Induces an Inflammatory and Toxic Response

Abstract

Oropouche virus (OROV) is an emerging arbovirus in South and Central Americas with high spreading potential. OROV infection has been associated with neurological complications and OROV genomic RNA has been detected in cerebrospinal fluid from patients, suggesting its neuroinvasive potential. Motivated by these findings, neurotropism and neuropathogenesis of OROV have been investigated in vivo in murine models, which do not fully recapitulate the complexity of the human brain. Here we have used slice cultures from adult human brains to investigate whether OROV is capable of infecting mature human neural cells in a context of preserved neural connections and brain cytoarchitecture. Our results demonstrate that human neural cells can be infected ex vivo by OROV and support the production of infectious viral particles. Moreover, OROV infection led to the release of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) and diminished cell viability 48 h post-infection, indicating that OROV triggers an inflammatory response and tissue damage. Although OROV-positive neurons were observed, microglia were the most abundant central nervous system (CNS) cell type infected by OROV, suggesting that they play an important role in the response to CNS infection by OROV in the adult human brain. Importantly, we found no OROV-infected astrocytes. To the best of our knowledge, this is the first direct demonstration of OROV infection in human brain cells. Combined with previous data from murine models and case reports of OROV genome detection in cerebrospinal fluid from patients, our data shed light on OROV neuropathogenesis and help raising awareness about acute and possibly chronic consequences of OROV infection in the human brain.

A Review of Omics Studies on Arboviruses: Alphavirus, Orthobunyavirus and Phlebovirus

“…Using sliced cultures from an adult human brain, Almeida and colleagues investigated OROV infection of mature human neural cells, which resulted in the release of TNF-α (pro-inflammatory cytokine tumour necrosis factor-alpha) and the reduction of cell viability and tissue damage in a 48-h period post-infection, which could generate further neuronal dysfunctions and neurological symptoms in human infections. Although OROV infects both neurons and microglia, the latter were the preferred central nervous system (CNS) cells infected by the virus, again demonstrating that OROV infection may lead to neuronal complications, as microglia cells are the primary defence cells in the CNS that might even serve as viral reservoirs in the brain [ 160 ]. OROV infection has also been studied in human blood mononuclear cells, and results demonstrated that T CD4+ lymphocytes (Jurkat cells) were more susceptible to infection than other lymphoid lineages.…”

The multitaskers of the brain: Glial responses to viral infections and associated post‐infectious neurologic sequelae

“…Astrocytes may similarly contribute to the cellular HIV reservoir (Lutgen et al, 2020; Valdebenito et al, 2021). The emerging RNA viruses Oropouche virus and Middle Eastern respiratory syndrome coronavirus infect neurons and glia in humanized mice or human brain slice cultures, leading to complement‐mediated BBB changes and microglial activation (Almeida et al, 2021; Jiang et al, 2021). Future studies will determine whether these effects are also observed in human patients.…”

“…Eastern respiratory syndrome coronavirus infect neurons and glia in humanized mice or human brain slice cultures, leading to complementmediated BBB changes and microglial activation (Almeida et al, 2021;Jiang et al, 2021). Future studies will determine whether these effects are also observed in human patients.…”

NMDA glutamate receptor antagonist MK‐801 induces proteome changes in adult human brain slices which are partially counteracted by haloperidol and clozapine

“…In all donors, the tissue collected was mapped as excluded from the epileptogenic zone. Our group has previously employed this experimental model to model molecular events associated with Alzheimer's disease (Mendes et al., 2018; Sebollela et al., 2012; Vasconcelos et al., 2021) and viral neuroinfection (Almeida et al., 2021; Crunfli et al., 2022; Figueiredo et al., 2019). We demonstrate that human brain slices preserve the human CNS complexity in terms of cell types found in vivo, validating our previous observations (Almeida et al., 2021; Crunfli et al., 2022; Figueiredo et al., 2019; Mendes et al., 2018; Sebollela et al., 2012; Vasconcelos et al., 2021).…”