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Sneha Singh, Gustavo Garcia, Ruchi Shah, Andrei A Kramerov, Alokkumar Jha, Vaithilingaraja Arumugaswami, Alexander V Ljubimov, Ashok Kumar; Differential innate immune response and replication of SARS-CoV-2 in human diabetic corneal epithelial cells. Invest. Ophthalmol. Vis. Sci. 2022;63(7):1670 – A0500.
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© ARVO (1962-2015); The Authors (2016-present)
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.
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.
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.
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.
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