Cardiomyocyte Cyclin-dependent kinase 9 directly binds to and phosphorylates NF-κB p65 subunit to drive cardiac inflammation and remodeling.

Summary

This mechanistic study shows that CDK9 directly binds to and phosphorylates NF-κB p65 in cardiomyocytes, driving inflammation and hypertrophic remodeling independently of IKKβ and RNAPII pathways. Genetic and pharmacologic inhibition of CDK9 signaling attenuated Ang II–induced cardiac inflammation, remodeling, and dysfunction in mice, nominating CDK9 as a therapeutic target in heart failure.

Key Findings

• CDK9 Thr-186 phosphorylation is increased in human and mouse hypertrophic hearts.
• Cardiomyocyte CDK9 T186A loss-of-function blunts Ang II–induced remodeling and NF-κB–mediated inflammation; T186E overactivation promotes them.
• CDK9 directly binds and phosphorylates NF-κB p65, enabling nuclear translocation and inflammatory/hypertrophic gene transcription independently of IKKβ and RNAPII pathways and requiring Cyclin T1.
• Pharmacological inhibition of CDK9 phosphorylation mitigates cardiac inflammation, remodeling, and dysfunction in mice.

Clinical Implications

CDK9 phosphorylation (Thr-186) and the CDK9–p65 interaction could serve as biomarkers and therapeutic targets. Development of selective CDK9 inhibitors and translational studies in human heart failure may yield anti-inflammatory, anti-remodeling therapies.

Limitations

• Preclinical study without human interventional validation.
• Potential off-target effects and long-term safety of CDK9 inhibition remain uncharacterized.

Future Directions

Develop selective CDK9 inhibitors, evaluate efficacy and safety in large-animal heart failure models, and pursue biomarker-guided early-phase clinical trials targeting the CDK9–p65 axis.