Abstract
Purpose :
Diabetes predisposes an individual to severe COVID-19. Diabetic cornea is also known to have impaired wound healing, increasing the chances of infection. Earlier, we reported the ability of SARS-CoV-2 to infect conjunctival cells, and the presence of viral RNA and proteins was also detected in the corneas of COVID-19 donors. In this study, we evaluated the effect of diabetes on corneal innate immune response during SARS-CoV-2 infection and sought to determine the underlying mechanisms.
Methods :
Human primary corneolimbal epithelial cells (HCECs) were isolated from the corneas of three diabetic and three non-diabetic donors. In vitro studies were performed by infecting HCECs with SARS-CoV-2 – USA-WA1/2020 strain at MOI 0.5. Viral replication was assessed by viral genome copy number. RNAseq analysis was performed to determine genes/pathways altered by diabetic vs non-diabetic HCECs. qPCR was used to assess the expression of innate inflammatory and antiviral genes. Western blot was performed to detect the protein expression of antiviral signaling molecules.
Results :
The primary HCECs were found permissive to SARS-CoV-2 infection, as evidenced by increased viral replication which peaked at day 3 p.i. along with an induction of p-STAT1. Interestingly, HCECs from diabetic cornea had higher viral RNA on all three days post-infection. SARS-CoV-2 infected HCECs exhibited induced expression of inflammatory genes and their levels were relatively higher in diabetic cells. RNA-seq analysis revealed significant differences in diabetic vs. non-diabetic SARS-CoV-2 infected cells with alteration in genes regulating viral response, inflammation, and injury. The most affected down-regulated genes are related to lipid metabolism, ferroptosis, and oxidative stress.
Conclusions :
Our study demonstrates increased SARS-CoV-2 replication and differential innate antiviral and inflammatory response in HCECs from diabetic corneas. These results indicate that diabetes is a potential risk for enhanced infectivity of SARS-CoV-2 for the ocular surface.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.