RESUMEN
COVID-19, caused by SARS-CoV-2, is a virulent pneumonia, with >4,000,000 confirmed cases worldwide and >290,000 deaths as of May 15, 2020. It is critical that vaccines and therapeutics be developed very rapidly. Mice, the ideal animal for assessing such interventions, are resistant to SARS-CoV-2. Here, we overcome this difficulty by exogenous delivery of human ACE2 with a replication-deficient adenovirus (Ad5-hACE2). Ad5-hACE2-sensitized mice developed pneumonia characterized by weight loss, severe pulmonary pathology, and high-titer virus replication in lungs. Type I interferon, T cells, and, most importantly, signal transducer and activator of transcription 1 (STAT1) are critical for virus clearance and disease resolution in these mice. Ad5-hACE2-transduced mice enabled rapid assessments of a vaccine candidate, of human convalescent plasma, and of two antiviral therapies (poly I:C and remdesivir). In summary, we describe a murine model of broad and immediate utility to investigate COVID-19 pathogenesis and to evaluate new therapies and vaccines.
Asunto(s)
Betacoronavirus/inmunología , Infecciones por Coronavirus/patología , Infecciones por Coronavirus/prevención & control , Modelos Animales de Enfermedad , Pandemias/prevención & control , Neumonía Viral/patología , Neumonía Viral/prevención & control , Vacunación , Enzima Convertidora de Angiotensina 2 , Animales , COVID-19 , Chlorocebus aethiops , Infecciones por Coronavirus/virología , Evaluación Preclínica de Medicamentos/métodos , Femenino , Humanos , Interferón gamma/genética , Interferón gamma/metabolismo , Pulmón/patología , Pulmón/virología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Peptidil-Dipeptidasa A/genética , Peptidil-Dipeptidasa A/metabolismo , Neumonía Viral/virología , Receptor de Interferón alfa y beta/genética , Receptor de Interferón alfa y beta/metabolismo , SARS-CoV-2 , Factor de Transcripción STAT1/genética , Factor de Transcripción STAT1/metabolismo , Organismos Libres de Patógenos Específicos , Transducción Genética , Células Vero , Carga Viral , Replicación ViralRESUMEN
BACKGROUND: Currently, direct conversion from somatic cells to neurons requires virus-mediated delivery of at least one transcriptional factor or a combination of several small-molecule compounds. Delivery of transcriptional factors may affect genome stability, while small-molecule compounds may require more evaluations when applied in vivo. Thus, a defined medium with only conventional growth factors or additives for cell culture is desirable for inducing neuronal trans-differentiation. RESULTS: Here, we report that a defined medium (5C) consisting of basic fibroblast growth factor (bFGF), N2 supplement, leukemia inhibitory factor, vitamin C (Vc), and ß-mercaptoethanol (ßMe) induces the direct conversion of somatic cells to cells with neuronal characteristics. Application of 5C medium converted mouse embryonic fibroblasts (MEFs) into TuJ+ neuronal-like cells, which were capable of survival after being transplanted into the mouse brain. The same 5C medium could convert primary rat astrocytes into neuronal-like cells with mature electrophysiology characteristics in vitro and facilitated the recovery of brain injury, possibly by inducing similar conversions, when infused into the mouse brain in vivo. Crucially, 5C medium could also induce neuronal characteristics in several human cell types. CONCLUSIONS: In summary, this 5C medium not only provides a means to derive cells with neuronal characteristics without viral transfection in vitro but might also be useful to produce neurons in vivo for neurodegenerative disease treatment.