(894) Covid19 Effects on V-ATPase Subunit Gene Expression in Ionocytes that Regulate Ion and pH Homeostasis in the Oral Cavity

Introduction/Rationale: Understanding innate immune responses to SARS-CoV-2 in oral minor salivary glands provides important insight into how the virus establishes infection and contributes to disease. Ionocytes in the oral cavity are still poorly defined, particularly in relation to ion transport and pH. An RNAseq UMAP of human minor salivary glands (https://www.covid19cellatlas.org/warner20/) identified buccal ionocytes expressing FoxI1, a specific biomarker, along with FoxI2, hBD-1, CFTR, ASCl3, NKCC1, and V-ATPase subunits ATP6V1G3 and ATP6V0D2. Here, mRNA expression of these V-ATPase genes was examined to understand the molecular identity of ionocytes during viral infection. We hypothesize that gene expression of ATP6V0D2 and ATP6V1G3 will be modulated by SARS-CoV-2 infection.

Methods: Buccal swabs were collected from September 2021 to February 2022. qRT-PCR was performed on total RNA extracted (Qiagen RNeasy Kit) from 47 COVID19(+) adults, 10 COVID19(-) patients and 16 recently recovered COVID-19(-) patients using an iScript and SYBR-green protocol, ATP6V1G3, ATP6V0D2, and -actin primers.

Results: A significant (p < 0.05, Mann-Whitney U) increase of ATP6V0D2 mRNA in COVID19 patients occurred compared with both non-COVID19 and recovered COVID19 patients. ATP6V1G3 mRNA was unchanged between all groups.

Conclusion: Buccal cells contain epithelial cells and ionocytes, explaining the increase of ATP6V0D2 in the Covid19 cohort. This suggests that Covid19 influences the ionocyte and may affect pH in oral minor salivary glands.