{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T16:55:41Z","timestamp":1792688141429,"version":"4.5.0"},"reference-count":47,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,1,19]],"date-time":"2021-01-19T00:00:00Z","timestamp":1611014400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000065","name":"National Institute of Neurological Disorders and Stroke","doi-asserted-by":"publisher","award":["R21NS099838"],"award-info":[{"award-number":["R21NS099838"]}],"id":[{"id":"10.13039\/100000065","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000052","name":"NIH Office of the Director","doi-asserted-by":"publisher","award":["R21OD024896"],"award-info":[{"award-number":["R21OD024896"]}],"id":[{"id":"10.13039\/100000052","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can cause neurological disease in humans, but little is known about the pathogenesis of SARS-CoV-2 infection in the central nervous system (CNS). Herein, using K18-hACE2 mice, we demonstrate that SARS-CoV-2 neuroinvasion and encephalitis is associated with mortality in these mice. Intranasal infection of K18-hACE2 mice with 105 plaque-forming units of SARS-CoV-2 resulted in 100% mortality by day 6 after infection. The highest virus titers in the lungs were observed on day 3 and declined on days 5 and 6 after infection. By contrast, very high levels of infectious virus were uniformly detected in the brains of all the animals on days 5 and 6. Onset of severe disease in infected mice correlated with peak viral levels in the brain. SARS-CoV-2-infected mice exhibited encephalitis hallmarks characterized by production of cytokines and chemokines, leukocyte infiltration, hemorrhage and neuronal cell death. SARS-CoV-2 was also found to productively infect cells within the nasal turbinate, eye and olfactory bulb, suggesting SARS-CoV-2 entry into the brain by this route after intranasal infection. Our data indicate that direct infection of CNS cells together with the induced inflammatory response in the brain resulted in the severe disease observed in SARS-CoV-2-infected K18-hACE2 mice.<\/jats:p>","DOI":"10.3390\/v13010132","type":"journal-article","created":{"date-parts":[[2021,1,21]],"date-time":"2021-01-21T02:36:05Z","timestamp":1611196565000},"page":"132","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":224,"title":["Neuroinvasion and Encephalitis Following Intranasal Inoculation of SARS-CoV-2 in K18-hACE2 Mice"],"prefix":"10.3390","volume":"13","author":[{"given":"Pratima","family":"Kumari","sequence":"first","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7300-6388","authenticated-orcid":false,"given":"Hussin A.","family":"Rothan","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Janhavi P.","family":"Natekar","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shannon","family":"Stone","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Heather","family":"Pathak","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philip G.","family":"Strate","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Komal","family":"Arora","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Margo A.","family":"Brinton","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0970-4875","authenticated-orcid":false,"given":"Mukesh","family":"Kumar","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"102433","DOI":"10.1016\/j.jaut.2020.102433","article-title":"The epidemiology and pathogenesis of coronavirus disease (COVID-19) outbreak","volume":"109","author":"Rothan","year":"2020","journal-title":"J. Autoimmun."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Rothan, H.A., Acharya, A., Reid, S.P., Kumar, M., and Byrareddy, S.N. (2020). Molecular Aspects of COVID-19 Differential Pathogenesis. Pathogens, 9.","DOI":"10.3390\/pathogens9070538"},{"key":"ref_3","first-page":"e7930","article-title":"Neurological Complications of Coronavirus Disease (COVID-19): Encephalopathy, MRI Brain and Cerebrospinal Fluid Findings: Case 2","volume":"12","author":"Espinosa","year":"2020","journal-title":"Cureus"},{"key":"ref_4","first-page":"e7352","article-title":"Neurological Complications of Coronavirus Disease (COVID-19): Encephalopathy","volume":"12","author":"Filatov","year":"2020","journal-title":"Cureus"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1186\/s13195-020-00640-3","article-title":"Immediate and long-term consequences of COVID-19 infections for the development of neurological disease","volume":"12","author":"Heneka","year":"2020","journal-title":"Alzheimer\u2019s Res. Ther."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"E270","DOI":"10.1148\/radiol.2020201933","article-title":"Imaging in Neurological Disease of Hospitalized COVID-19 Patients: An Italian Multicenter Retrospective Observational Study","volume":"297","author":"Mahammedi","year":"2020","journal-title":"Radiology"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1329","DOI":"10.1016\/j.acra.2020.05.024","article-title":"Neurological Dysfunction in Coronavirus Disease-19 (COVID-19)","volume":"27","author":"Parry","year":"2020","journal-title":"Acad. Radiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1845","DOI":"10.1002\/jmv.26105","article-title":"Potential neuroinvasive pathways of SARS-CoV-2: Deciphering the spectrum of neurological deficit seen in coronavirus disease-2019 (COVID-19)","volume":"92","author":"Baig","year":"2020","journal-title":"J. Med. Virol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Adamczyk-Sowa, M., Niedziela, N., Kubicka-Baczyk, K., Wierzbicki, K., Jaroszewicz, J., and Sowa, P. (2020). Neurological symptoms as a clinical manifestation of COVID-19: Implications for internists. Polish Arch. Intern. Med.","DOI":"10.20452\/pamw.15575"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1756286420917830","DOI":"10.1177\/1756286420917830","article-title":"Potential neurological symptoms of COVID-19","volume":"13","author":"Wang","year":"2020","journal-title":"Ther. Adv. Neurol. Disord."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"4393","DOI":"10.2741\/3012","article-title":"Mouse hepatitis virus infection of the CNS: A model for defense, disease, and repair","volume":"13","author":"Schaumburg","year":"2008","journal-title":"Front. Biosci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1051","DOI":"10.1007\/s13760-020-01412-4","article-title":"Neurological manifestations of COVID-19, SARS and MERS","volume":"120","author":"Verstrepen","year":"2020","journal-title":"Acta Neurol Belg."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1116","DOI":"10.1161\/01.HYP.0000125143.73301.94","article-title":"Adjacent expression of renin and angiotensinogen in the rostral ventrolateral medulla using a dual-reporter transgenic model","volume":"43","author":"Lavoie","year":"2004","journal-title":"Hypertension"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1111\/jnc.13641","article-title":"Angiotensin II regulation of angiotensin-converting enzymes in spontaneously hypertensive rat primary astrocyte cultures","volume":"138","author":"Gowrisankar","year":"2016","journal-title":"J. Neurochem."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Lukiw, W.J., Pogue, A., and Hill, J.M. (2020). SARS-CoV-2 Infectivity and Neurological Targets in the Brain. Cell. Mol. Neurobiol., 1\u20138.","DOI":"10.1007\/s10571-020-00947-7"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"590","DOI":"10.1056\/NEJMc2011400","article-title":"Multiorgan and Renal Tropism of SARS-CoV-2","volume":"383","author":"Puelles","year":"2020","journal-title":"N. Engl. J. Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"989","DOI":"10.1056\/NEJMc2019373","article-title":"Neuropathological Features of Covid-19","volume":"383","author":"Solomon","year":"2020","journal-title":"N. Engl. J. Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"928","DOI":"10.1038\/s41422-020-0390-x","article-title":"SARS-CoV-2 infects human neural progenitor cells and brain organoids","volume":"30","author":"Zhang","year":"2020","journal-title":"Cell Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e106230","DOI":"10.15252\/embj.2020106230","article-title":"SARS-CoV-2 targets neurons of 3D human brain organoids","volume":"39","author":"Ramani","year":"2020","journal-title":"EMBO J."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"e109","DOI":"10.1016\/S0140-6736(20)31282-4","article-title":"Early evidence of pronounced brain involvement in fatal COVID-19 outcomes","volume":"395","author":"Kaufmann","year":"2020","journal-title":"Lancet"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"102799","DOI":"10.1016\/j.ebiom.2020.102799","article-title":"Infectivity of human coronavirus in the brain","volume":"56","author":"Cheng","year":"2020","journal-title":"EBioMedicine"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"e142032","DOI":"10.1172\/jci.insight.142032","article-title":"Human angiotensin-converting enzyme 2 transgenic mice infected with SARS-CoV-2 develop severe and fatal respiratory disease","volume":"5","author":"Golden","year":"2020","journal-title":"JCI Insight"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1327","DOI":"10.1038\/s41590-020-0778-2","article-title":"SARS-CoV-2 infection of human ACE2-transgenic mice causes severe lung inflammation and impaired function","volume":"21","author":"Winkler","year":"2020","journal-title":"Nat. Immunol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1215","DOI":"10.4269\/ajtmh.20-0762","article-title":"Evaluation of K18-hACE2 Mice as a Model of SARS-CoV-2 Infection","volume":"103","author":"Moreau","year":"2020","journal-title":"Am. J. Trop. Med. Hyg."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Zheng, J., Wong, L.R., Li, K., Verma, A.K., Ortiz, M., Wohlford-Lenane, C., Leidinger, M.R., Knudson, C.M., Meyerholz, D.K., and McCray, P.B. (2020). COVID-19 treatments and pathogenesis including anosmia in K18-hACE2 mice. Nature, 1\u20135.","DOI":"10.1101\/2020.08.07.242073"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1127","DOI":"10.1084\/jem.172.4.1127","article-title":"Effect of olfactory bulb ablation on spread of a neurotropic coronavirus into the mouse brain","volume":"172","author":"Perlman","year":"1990","journal-title":"J Exp. Med."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"7264","DOI":"10.1128\/JVI.00737-08","article-title":"Severe acute respiratory syndrome coronavirus infection causes neuronal death in the absence of encephalitis in mice transgenic for human ACE2","volume":"82","author":"Netland","year":"2008","journal-title":"J. Virol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.virol.2020.05.002","article-title":"The FDA-approved gold drug auranofin inhibits novel coronavirus (SARS-COV-2) replication and attenuates inflammation in human cells","volume":"547","author":"Rothan","year":"2020","journal-title":"Virology"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Rothan, H.A., Arora, K., Natekar, J.P., Strate, P.G., Brinton, M.A., and Kumar, M. (2019). Z-DNA-Binding Protein 1 Is Critical for Controlling Virus Replication and Survival in West Nile Virus Encephalitis. Front. Microbiol., 10.","DOI":"10.3389\/fmicb.2019.02089"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Natekar, J.P., Rothan, H.A., Arora, K., Strate, P.G., and Kumar, M. (2019). Cellular microRNA-155 Regulates Virus-Induced Inflammatory Response and Protects against Lethal West Nile Virus Infection. Viruses, 12.","DOI":"10.3390\/v12010009"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3655","DOI":"10.1128\/JVI.02667-12","article-title":"Inflammasome adaptor protein Apoptosis-associated speck-like protein containing CARD (ASC) is critical for the immune response and survival in west Nile virus encephalitis","volume":"87","author":"Kumar","year":"2013","journal-title":"J. Virol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1186\/s12985-017-0750-4","article-title":"A guinea pig model of Zika virus infection","volume":"14","author":"Kumar","year":"2017","journal-title":"Virol. J."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"259","DOI":"10.3389\/fmicb.2019.00259","article-title":"Deletion of Pregnancy Zone Protein and Murinoglobulin-1 Restricts the Pathogenesis of West Nile Virus Infection in Mice","volume":"10","author":"Krause","year":"2019","journal-title":"Front. Microbiol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1186\/1742-2094-11-80","article-title":"Reduced immune cell infiltration and increased pro-inflammatory mediators in the brain of Type 2 diabetic mouse model infected with West Nile virus","volume":"11","author":"Kumar","year":"2014","journal-title":"J. Neuroinflamm."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"178","DOI":"10.1186\/s12974-015-0400-y","article-title":"Induction of virus-specific effector immune cell response limits virus replication and severe disease in mice infected with non-lethal West Nile virus Eg101 strain","volume":"12","author":"Kumar","year":"2015","journal-title":"J. Neuroinflamm."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1128\/JVI.02012-06","article-title":"Lethal infection of K18-hACE2 mice infected with severe acute respiratory syndrome coronavirus","volume":"81","author":"McCray","year":"2007","journal-title":"J. Virol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.chom.2016.01.006","article-title":"The Evolution of Antiviral Defense Systems","volume":"19","author":"tenOever","year":"2016","journal-title":"Cell Host Microbe"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1126\/science.1183021","article-title":"Regulation of adaptive immunity by the innate immune system","volume":"327","author":"Iwasaki","year":"2010","journal-title":"Science"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"9829","DOI":"10.1128\/JVI.01199-08","article-title":"Murine coronavirus mouse hepatitis virus is recognized by MDA5 and induces type I interferon in brain macrophages\/microglia","volume":"82","author":"Bender","year":"2008","journal-title":"J. Virol."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Meinhardt, J., Radke, J., Dittmayer, C., Franz, J., Thomas, C., Mothes, R., Laue, M., Schneider, J., Brunink, S., and Greuel, S. (2020). Olfactory transmucosal SARS-CoV-2 invasion as a port of central nervous system entry in individuals with COVID-19. Nat. Neurosci., 1\u20138.","DOI":"10.1038\/s41593-020-00758-5"},{"key":"ref_41","first-page":"69","article-title":"Smell and taste dysfunction in patients with SARS-CoV-2 infection: A review of epidemiology, pathogenesis, prognosis, and treatment options","volume":"38","author":"Kanjanaumporn","year":"2020","journal-title":"Asian Pac. J. Allergy Immunol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"856","DOI":"10.1126\/science.abd2985","article-title":"Neuropilin-1 facilitates SARS-CoV-2 cell entry and infectivity","volume":"370","author":"Ojha","year":"2020","journal-title":"Science"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"e00404","DOI":"10.1128\/JVI.00404-18","article-title":"Axonal Transport Enables Neuron-to-Neuron Propagation of Human Coronavirus OC43","volume":"92","author":"Dube","year":"2018","journal-title":"J. Virol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1016\/j.coviro.2014.12.009","article-title":"Viral diseases of the central nervous system","volume":"11","author":"Swanson","year":"2015","journal-title":"Curr. Opin. Virol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1002\/path.4461","article-title":"The olfactory nerve: A shortcut for influenza and other viral diseases into the central nervous system","volume":"235","author":"Verdijk","year":"2015","journal-title":"J. Pathol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1374","DOI":"10.1016\/S0140-6736(74)92234-X","article-title":"Neural route of infection in viral diseases of the central nervous system","volume":"2","author":"Blinzinger","year":"1974","journal-title":"Lancet"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1021\/acschemneuro.6b00043","article-title":"The Olfactory Bulb: An Immunosensory Effector Organ during Neurotropic Viral Infections","volume":"7","author":"Durrant","year":"2016","journal-title":"ACS Chem. Neurosci."}],"container-title":["Viruses"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1999-4915\/13\/1\/132\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:12:44Z","timestamp":1760159564000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1999-4915\/13\/1\/132"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,1,19]]},"references-count":47,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2021,1]]}},"alternative-id":["v13010132"],"URL":"https:\/\/doi.org\/10.3390\/v13010132","relation":{"has-preprint":[{"id-type":"doi","id":"10.1101\/2020.12.14.422714","asserted-by":"object"}]},"ISSN":["1999-4915"],"issn-type":[{"value":"1999-4915","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,1,19]]}}}