# Epitranscriptomic Modulation of TET2 Inhibition Suppressed SARS-CoV-2 Infection and Blocked Viral Nucleocapsid Protein in Induced-Pluripotent-Stem-Cell-Derived Cardiomyocyte Screening Models

## TL;DR

This study shows that inhibiting TET2, an enzyme involved in DNA modification, can reduce SARS-CoV-2 infection and viral protein levels in heart cells, suggesting a new treatment approach.

## Contribution

The study identifies TET2 as a key regulator in SARS-CoV-2 infection and introduces Bobcat339 as a promising antiviral compound through epitranscriptomic modulation.

## Key findings

- TET2 inhibition reduces SARS-CoV-2 nucleocapsid protein levels and viral replication in heart cells.
- Bobcat339, a TET2 inhibitor, shows strong antiviral effects and binds to multiple viral targets.
- TET2 knockdown suppresses 5-hydroxymethylcytosine levels in infected cells.

## Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral infection has been associated with severe cardiovascular complications. However, the role of epitranscriptional modulation involved in SARS-CoV-2-infected myocarditis is still unclear. Ten-eleven translocation 2 (TET2), a methylcytosine dioxygenase, plays key roles in DNA demethylation during viral infection and host–virus interactions. Using human-induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) as a platform, our data revealed the epitranscriptomic role of TET2 during SARS-CoV-2 infection. First, our RNA sequencing analysis revealed the alterations of the messenger-RNA-expression profiles of epitranscriptomic regulators, including TET2, in hiPSC-CMs during SARS-CoV-2 infection. Second, silencing TET2 markedly reduced both the messenger RNA and protein levels of the viral nucleocapsid (N) protein, leading to attenuated viral replication in infected hiPSC-CMs. Furthermore, RNA dot-blotting analysis revealed that TET2 knockdown suppressed the levels of 5-hydroxymethylcytosine in SARS-CoV-2-infected hiPSC-CMs. To further explore the therapeutic relevance of TET2 inhibition in suppressing SARS-CoV-2 infection, we screened and compared 3 structurally distinct TET2 enzymatic inhibitors: Bobcat339, TETi76, and TFMB-2HG. Among these, Bobcat339 demonstrated the most potent antiviral effect, markedly suppressing SARS-CoV-2 replication and N-protein expression. Molecular docking analysis revealed that Bobcat339 exhibited a high binding affinity for multiple viral targets, including nsp16, RdRp, and N protein, indicating a multitarget mechanism of action. In addition, our data demonstrated that treatment with Bobcat339 can suppress SARS-CoV-2 infectious activity and N-protein expression in infected hiPSC-CMs. Together, our findings highlight the regulatory role of TET2 in SARS-CoV-2 infection and identify Bobcat339 as a promising therapeutic compound. Understanding TET2-driven epitranscriptomics and the functions of TET-targeting inhibitors may provide a novel strategy for mitigating viral infection in SARS-CoV-2-induced cardiomyopathy.