Study Illuminates How COVID-19 May Gain Access to the Brain Via Interaction with Astrocytes; Both Astrocytes and Neurons Express ACE2 Receptor and Can Be Infected by SARS-CoV-2; But Astrocytes Less Susceptible to Infection Than Neurons

New research offers an up-close view of how SARS-CoV-2, the virus that causes COVID-19, can spread to the brain. The study helps explain the alarming array of neurological symptoms reported in some patients with COVID-19, as well as why some patients suffer severe neurological effects while others experience none at all. The researchers report evidence that SARS-CoV-2 can infect both the nerve cells that power our brains (neurons), and the cells in the brain and spinal cord that support and protect neurons (astrocytes). "Our findings suggest that astrocytes are a pathway through which COVID-19 causes neurological damage," said Ricardo Costa, PhD, a postdoctoral fellow at the Louisiana State University (LSU) Health Shreveport and the study's first author. "This could explain many of the neurologic symptoms we see in COVID-19 patients, which include loss of sense of smell and taste, disorientation, psychosis, and stroke." Dr. Costa presented the team’s research on April 27 at the American Physiological Society annual meeting during the Experimental Biology (EB) 2021 meeting, held virtually April 27-30. The study is led by Diana Cruz-Topete, PhD, Assistant Professor of Molecular and Cellular Biology at LSU Health Shreveport, and includes collaborators Oscar Gomez-Torres, PhD, and Emma Burgos-Ramos, PhD, from the Universidad de Castilla-La Mancha in Spain. In the respiratory system, SARS-CoV-2 is known to infect a person's cells by grabbing hold of proteins on the cell surface called angiotensin-converting enzyme-2 (ACE2) receptors. It has been unclear whether brain cells have this receptor. For their study, Dr. Costa and colleagues examined RNA and proteins to determine whether cell cultures of human astrocytes and neurons expressed ACE2. They then exposed the cells to a version of the SARS-CoV-2 virus that had been modified to be safe for researchers to handle. The studies confirmed that both astrocytes and neurons express the ACE2 receptor and that both cell types can become infected with SARS-CoV-2, though astrocytes were less likely to become infected.