Brain tissues from COVID-19 (n=12) and other disease control (ODC) (n=12) patients, as well as primary human neural cells and Syrian hamsters, infected with a clinical variant of SARS-CoV-2, were investigated by ddPCR, RT-qPCR and immunodetection methods. SARS-CoV-2 RNA was detected in the CNS of four patients with COVID-19 with viral protein (NSP3 and spike) immunodetection in the brainstem. Olfactory bulb, brainstem, and cerebrum from patients with COVID-19 showed induction of pro-inflammatory transcripts (IL8, IL18, CXCL10, NOD2) and cytokines (GM-CSF and IL-18) compared to CNS tissues from ODC patients (p<0.05). Peroxisome biogenesis factor transcripts (PEX3, PEX5L, PEX11β and PEX14) and proteins (PEX3, PEX14, PMP70) were suppressed in the CNS of COVID-19 patients compared to ODCs (p<0.05). SARS-CoV-2 infection of hamsters revealed viral RNA detection in the olfactory bulb at days 4 and 7 post-infection while inflammatory gene expression was upregulated in the cerebrum of infected animals by day 14 post-infection (p<0.05). Pex3 transcript levels together with catalase and PMP70 immunoreactivity were suppressed in the cerebrum of SARS-CoV-2 infected animals (p<0.05). The authors concluded that COVID-19 induced sustained neuroinflammatory responses with peroxisome biogenesis factor suppression despite limited brainstem SARS-CoV-2 neurotropism in humans. These observations offer insights into developing biomarkers and therapies, while also implicating persistent peroxisome dysfunction as a contributor to the neurological post-acute sequelae of COVID-19.
Roczkowsky A, Limonta D, Fernandes JP, Branton WG, Clarke M, Hlavay B, Noyce RS, Joseph JT, Ogando NS, Das SK, Elaish M, Arbour N, Evans DH, Langdon K, Hobman TC, Power C. COVID-19 induces neuroinflammation and suppresses peroxisomes in the brain. Ann Neurol. 2023 May 15.
doi: 10.1002/ana.26679