3D Bioprinted Neural‐Like Tissue as a Platform to Study Neurotropism of Mouse‐Adapted SARS‐CoV‐2

Abstract The effects of neuroinvasion by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) become clinically relevant due to the numerous neurological symptoms observed in Corona Virus Disease 2019 (COVID‐19) patients during infection and post‐COVID syndrome or long COVID. This study reports the biofabrication of a 3D bioprinted neural‐like tissue as a proof‐of‐concept platform for a more representative study of SARS‐CoV‐2 brain infection. Bioink is optimized regarding its biophysical properties and is mixed with murine neural cells to construct a 3D model of COVID‐19 infection. Aiming to increase the specificity to murine cells, SARS‐CoV‐2 is mouse‐adapted (MA‐SARS‐CoV‐2) in vitro, in a protocol first reported here. MA‐SARS‐CoV‐2 reveals mutations located at the Orf1a and Orf3a domains and is evolutionarily closer to the original Wuhan SARS‐CoV‐2 strain than SARS‐CoV‐2 used for adaptation. Remarkably, MA‐SARS‐CoV‐2 shows high specificity to murine cells, which present distinct responses when cultured in 2D and 3D systems, regarding cell morphology, neuroinflammation, and virus titration. MA‐SARS‐CoV‐2 represents a valuable tool in studies using animal models, and the 3D neural‐like tissue serves as a powerful in vitro platform for modeling brain infection, contributing to the development of antivirals and new treatments for COVID‐19.