# Potential Cardioprotective Effect of a GRK5 Inhibitor Against NF-κB-Mediated Inflammation in an Animal Model of Isoproterenol-Induced Myocardial Infarction

## TL;DR

This study shows that Amlexanox, a GRK5 inhibitor, may protect the heart by reducing inflammation in a mouse model of heart attack.

## Contribution

The novel finding is that Amlexanox reduces NF-κB-mediated inflammation via GRK5 inhibition in myocardial infarction.

## Key findings

- Amlexanox significantly reduced cardiac injury biomarkers and IL-6 in mice with induced myocardial infarction.
- Treatment with Amlexanox decreased NF-κB(p65) and (p105) expression in cardiac myocytes.
- Amlexanox upregulated GRK5 and MEF2α protein levels, suggesting a modulatory role in cardioprotection.

## Abstract

Myocardial infarction (MI) is a pathological condition associated with various cardiovascular diseases and leads to heart failure. Nuclear factor-kappa B (NF-κB) is upregulated in the infarcted heart. G protein-coupled receptor kinase 5 (GRK5) also plays a complex role in both tissue repair and maladaptive hypertrophy in cardiovascular diseases; however, its effect on NF-κB-mediated inflammation has not yet been elucidated. Thus, this study aims to investigate the effects of Amlexanox (AMX), a potential GRK5 inhibitor, in an animal model of MI by assessing its impact on GRK5-mediated NF-κB/inflammatory processes. Thirty-two male mice were randomly allocated into four groups: control, MI, (MI treated with vehicle (MI + V), and MI + AMX (AMX: 2.5 mg/100 g/day). MI was induced using ISO on days 21 and 22. The cardioprotective impacts of Amlexanox were verified by evaluating cardiac injury, inflammatory biomarker concentrations, and histopathological alterations in cardiomyocytes. MI induction was confirmed by increases in heart weight/body weight ratio (HW/BW) (p < 0.001), troponin (p < 0.001), creatine kinase (p < 0.001), and LDH (p < 0.001). Treatment with AMX resulted in a significant reduction in cardiac injury biomarkers (p < 0.001) and IL-6 (p < 0.05). The protein level of NF-κB(p65) and NF-κB(p105) was significantly increased in cardiac myocytes of the MI group. Treatment with AMX led to a significant decrease in NF-κB(p65) and (p105) expression (p < 0.01 and p < 0.001, respectively), and GRK5 and MEF2α protein levels were also upregulated. In conclusion, AMX shows potential cardioprotective effects by modulating the GRK5/MEF2-mediated NF-κB inflammatory signaling pathway.