ABSTRACT
Since the global outbreak of SARS-CoV-2 (COVID-19), infections of diverse human organs along with multiple symptoms continue to be reported. However, the susceptibility of the brain to SARS-CoV-2, and the mechanisms underlying neurological infection are still elusive. Here, we utilized human embryonic stem cell-derived brain organoids and monolayer cortical neurons to investigate infection of brain with pseudotyped SARS-CoV-2 viral particles. Spike-containing SARS-CoV-2 pseudovirus infected neural layers within brain organoids. The expression of ACE2, a host cell receptor for SARS-CoV-2, was sustained during the development of brain organoids, especially in the somas of mature neurons, while remaining rare in neural stem cells. However, pseudotyped SARS-CoV-2 was observed in the axon of neurons, which lack ACE2. Neural infectivity of SARS-CoV-2 pseudovirus did not increase in proportion to viral load, but only 10% of neurons were infected. Our findings demonstrate that brain organoids provide a useful model for investigating SARS-CoV-2 entry into the human brain and elucidating the susceptibility of the brain to SARS-CoV-2.
Subject(s)
Betacoronavirus/physiology , Neurons/virology , Organoids/virology , Prosencephalon/virology , Spike Glycoprotein, Coronavirus/physiology , Angiotensin-Converting Enzyme 2 , Axons/enzymology , Cell Differentiation , Cells, Cultured , Cerebral Cortex/cytology , Embryonic Stem Cells/virology , HEK293 Cells , Humans , Nerve Tissue Proteins/physiology , Neural Stem Cells/enzymology , Neural Stem Cells/virology , Neurons/enzymology , Peptidyl-Dipeptidase A/physiology , Prosencephalon/cytology , Receptors, Virus/physiology , SARS-CoV-2 , Viral Load , Viral Tropism , Virus InternalizationABSTRACT
The recent outbreak of 2019 coronavirus disease (COVID-19), caused by a novel coronavirus, has now spread quickly worldwide. Like the severe acute respiratory syndrome coronavirus (SARS-CoV), this novel type of coronavirus, SARS-CoV-2, has been demonstrated to utilize angiotensin-converting enzyme 2 (ACE2) as an entry point to the cells. There is a growing body of reports indicating that COVID-19 patients, especially those in severe condition, exhibit neurological symptoms, thus supporting the possibility that SARS-CoV-2 could infect and damage neurons within the central nervous system in humans. Using human pluripotent stem cells-derived neurons, here we show the expression of ACE2 in human neurons via immunocytochemistry. From this perspective, we elaborate on the idea that the neuro-invasive potential of SARS-CoV-2 should be considered as a possible contributory factor, as well as a therapeutic target, for the severe respiratory symptoms in critical COVID-19 cases.