Abstract
Anosmia, loss of smell, is a prevalent symptom of SARS-CoV-2 infection. Anosmia may be explained by several mechanisms driven by infection of non-neuronal cells and damage in the nasal epithelium rather than direct infection of olfactory sensory neurons (OSNs). Previously, we showed that viral proteins are sufficient to cause neuroimmune responses in the teleost olfactory organ (OO). We hypothesize that SARS-CoV-2 spike (S) protein is sufficient to cause olfactory damage and olfactory dysfunction. Using an adult zebrafish model, we report that intranasally delivered SARS-CoV-2 S RBD mostly binds to the non-sensory epithelium of the olfactory organ and causes severe olfactory histopathology characterized by loss of cilia, hemorrhages and edema. Electrophysiological recordings reveal impaired olfactory function to both food and bile odorants in animals treated intranasally with SARS-CoV-2 S RBD. However, no loss of behavioral preference for food was detected in SARS-CoV-2 S RBD treated fish. Single cell RNA-Seq of the adult zebrafish olfactory organ indicated widespread loss of olfactory receptor expression and inflammatory responses in sustentacular, endothelial, and myeloid cell clusters along with reduced numbers of T regs . Combined, our results demonstrate that intranasal SARS-CoV-2 S RBD is sufficient to cause structural and functional damage to the zebrafish olfactory system. These findings may have implications for intranasally delivered vaccines against SARS-CoV-2.
Keywords: Animal models; EOG; Olfactory damage; Olfactory receptor expression; SARS-CoV-2; Spike protein; Zebrafish (Danio rerio).
【저자키워드】 SARS-CoV-2, animal models, Spike protein, EOG, Olfactory damage, Olfactory receptor expression, Zebrafish (Danio rerio)., 【초록키워드】 Vaccine, Inflammatory responses, spike, SARS-COV-2 infection, Infection, Viral proteins, Symptom, animal models, olfactory dysfunction, Spike protein, Histopathology, Anosmia, Protein, animals, RBD, animal, response, edema, Cluster, receptor, cilia, zebrafish, expression, mechanism, intranasal, SARS-CoV-2 spike, food, Inflammatory response, hemorrhage, olfactory, olfactory function, olfactory receptor, fish, Loss of Smell, endothelial, Viral protein, sensory neuron, damage, nasal epithelium, SARS-CoV-2 S, organ, direct infection, hemorrhages, myeloid cell, widespread, implication, Cell, prevalent, Combined, bind, non-neuronal cells, Olfactory organ, intranasally, indicated, reduced, characterized, treated, functional, explained, cause, driven by, Danio, non-neuronal cell, 【제목키워드】 Inflammation, Spike protein, SARS-CoV-2 spike protein, olfactory,