Coronavirus pathogenesis in mice explains the SARS-CoV-2 multi-organ spread by red blood cells hitch-hiking

SARS-CoV-2 infection causes a multisystemic disease that affects numerous organs beyond the respiratory system. Thus, it is well known that COVID-19 is associated with a wide range of hematological disorders; however, it remains unclear how the SARS-CoV-2 virus is able to navigate from tissue to tissue. In this work, we performed a comprehensive analysis of the pleiotropic effects of a prototypical coronavirus in its natural host, the validated preclinical model of murine hepatitis virus (MHV). Throughout this study we compared our results with the real-world data from COVID-19 patients (including autopsies). Thus, the presence of viral RNA was only detected in less than 25% of the human serum samples, whereas all had multiple positive nasal swabs for SARS-CoV-2. Notably, we found viral RNA not only in lungs, but also in heart and kidney of deceased COVID-19 patients. Subsequently, we investigated the association between viral organotropism and clinical manifestations employing the MHV murine model. Results from RT-qPCR and viral infectivity showcased the presence of viral RNA and infectious particles in multiple organs including liver, lung, brain, heart, kidney, spleen and pancreas, and even the blood of infected mice. Surprisingly, when comparing plasma and red blood cells (RBCs)-enriched fraction, higher viral load levels were detected in RBCs, with decreased RBC count, and hematocrit and hemoglobin levels in infected mice. Next, we treated infected mice with hemin triggering more aggressive symptoms. Strikingly, when combining hemin treatment with chloroquine (a compound that known to interact with the heme group and induces a conformational change in its structure) the infection and its clinical manifestations were distinctly attenuated. Computational docking suggested that heme is able to bind to MHV Spike protein in a similar way to the one, experimentally observed for SARS-CoV-2. Overall, our results lead to a global perspective of COVID-19 beyond the canonical focus on the respiratory system, and strongly support the multi-organ extent of coronavirus infection through specific interactions with RBC hemoproteins. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was funded by Agencia Nacional de Promocion de la Investigacion, el Desarrollo Tecnologico y la Innovacion (ANPCyT), Argentina: PICT 2018-02639, and PICT 2019-03215 CONICET; Fundacion Florencio Fiorini; National University of Quilmes Grant Program, Argentina, UNQ 1297/19; Institut Pasteur de Montevideo and FOCEM (MERCOSUR Structural Convergence Fund), COF 03/11; Institut Pasteur-Fiocruz-USP grant; G4 program Institut Pasteur Montevideo; Centro Latinoamericano de Biotecnologia (CABBIO). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All procedures performed in studies involving human subjects were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Documented approval was obtained from the Ethics Committees of Hospital Espanol (Administracion de los servicios de Salud del Estado, Uruguay). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors