Monkeypox virus infection of human astrocytes causes gasdermin B cleavage and pyroptosis
Hajar Miranzadeh Mahabadi1, Y C James Lin2, Natacha S Ogando1
1Department of Medicine, University of Alberta, Edmonton, AB T5N 2S2, Canada.
Abstract:
Monkeypox virus (MPXV) infections in humans cause neurological disorders while studies of MPXV-infected animals indicate that the virus penetrates the brain. Pyroptosis is an inflammatory type of regulated cell death, resulting from plasma membrane rupture (PMR) due to oligomerization of cleaved gasdermins to cause membrane pore formation. Herein, we investigated the human neural cell tropism of MPXV compared to another orthopoxvirus, vaccinia virus (VACV), as well as its effects on immune responses and cell death. Astrocytes were most permissive to MPXV (and VACV) infections, followed by microglia and oligodendrocytes, with minimal infection of neurons based on plaque assays. Aberrant morphological changes were evident in MPXV-infected astrocytes that were accompanied with viral protein (I3) immunolabelling and detection of over 125 MPXV-encoded proteins in cell lysates by mass spectrometry. MPXV- and VACV-infected astrocytes showed increased expression of immune gene transcripts (IL12, IRF3, IL1B, TNFA, CASP1, and GSDMB). However, MPXV infection of astrocytes specifically induced proteolytic cleavage of gasdermin B (GSDMB) (50 kDa), evident by the appearance of cleaved N-terminal-GSDMB (30 kDa) and C-terminal- GSDMB (18 kDa) fragments. GSDMB cleavage was associated with release of lactate dehydrogenase and increased cellular nucleic acid staining, indicative of PMR. Pre-treatment with dimethyl fumarate reduced cleavage of GSDMB and associated PMR in MPXV-infected astrocytes. Human astrocytes support productive MPXV infection, resulting in inflammatory gene induction with accompanying GSDMB-mediated pyroptosis. These findings clarify the recently recognized neuropathogenic effects of MPXV in humans while also offering potential therapeutic options.
Insights
Monkeypox virus (MPXV) infects human astrocytes, causing cell death through gasdermin B (GSDMB)-mediated pyroptosis. This research clarifies MPXV neuropathogenesis and suggests dimethyl fumarate as a potential therapy.
Area of Science:
- Neurovirology
- Immunology
- Cellular Biology
Background:
- Monkeypox virus (MPXV) causes neurological disorders, with evidence of brain penetration.
- Pyroptosis is an inflammatory cell death pathway involving gasdermin cleavage and plasma membrane rupture (PMR).
- Understanding MPXV's interaction with neural cells is crucial for addressing its neuropathogenic effects.
Purpose of the Study:
- To investigate the tropism of MPXV in human neural cells compared to vaccinia virus (VACV).
- To examine the effects of MPXV infection on immune responses and cell death mechanisms.
- To identify potential therapeutic targets for MPXV-induced neuropathology.
Main Methods:
- Infection of human astrocytes, microglia, and neurons with MPXV and VACV.
- Plaque assays to determine viral tropism.
- Mass spectrometry for viral protein detection, gene expression analysis, and assessment of gasdermin B (GSDMB) cleavage.
- Lactate dehydrogenase release and nucleic acid staining to indicate plasma membrane rupture (PMR).
- Treatment with dimethyl fumarate to evaluate therapeutic potential.
Main Results:
- Astrocytes were the most permissive neural cells to MPXV and VACV infection.
- MPXV infection induced aberrant astrocyte morphology, viral protein expression, and increased immune gene transcripts.
- MPXV specifically triggered GSDMB cleavage, leading to PMR and pyroptosis, which was reduced by dimethyl fumarate.
Conclusions:
- Human astrocytes support productive MPXV infection, inducing inflammatory responses and GSDMB-mediated pyroptosis.
- These findings elucidate the mechanisms behind MPXV's neuropathogenic effects.
- Dimethyl fumarate shows promise in mitigating MPXV-induced cell damage.
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