A novel small molecule inhibitor of p38⍺ MAP kinase augments cardiomyocyte cell cycle entry in response to direct cell cycle stimulation

Abstract

Background and PurposeMyocardial infarction (MI) is the leading cause of mortality globally due in part to the limited ability of cardiomyocytes (CMs) to regenerate. Recently, we demonstrated that overexpression of 4 cell cycle factors, CDK1, CDK4, cyclin B1, and cyclin D1 (4F), induced cell division in ~20% of the post‐mitotic CMs overexpressed 4F. The current study aims to identify a small molecule that augments 4F‐induced CM cycle induction.Experimental Approach, Key ResultsScreening of small molecules with a potential to augment 4F‐induced cell‐cycle induction in 60‐day‐old mature human induced pluripotent cardiomyocytes (hiPS‐CMs) revealed N‐(4,6‐Dimethylpyridin‐2‐yl)‐4‐(pyridine‐4‐yl)piperazine‐1‐carbothioamide (NDPPC), which activates cell cycle progression in 4F‐transduced hiPS‐CMs. Autodock tool and Autodock vina computational methods showed that NDPPC has a potential interaction with the binding site at the human p38⍺ mitogen‐activated protein kinase (p38⍺ MAP kinase), a critical negative regulator of the mammalian cell cycle. A p38 MAP kinase activity assay showed that NDPPC inhibits p38⍺ with 5‐10 times lower IC50 compared to the other P38 isoforms in a dose‐dependent manner. Overexpression of p38⍺ MAP kinase in CMs inhibited 4F cell cycle induction, and treatment with NDPPC reversed the cell cycle inhibitory effect.Conclusion and ImplicationsNDPPC is a novel inhibitor for p38 MAP kinase and is a promising drug to augment CM cell cycle response to the 4F. NDPPC could become an adjunct treatment with other cell cycle activators for heart failure treatment.

Pharmacological or genetic inhibition of LTCC promotes cardiomyocyte proliferation through inhibition of calcineurin activity.

“…The small molecule screen as well as the single cell transcriptomics data both suggested the role of LTCC-RRAD in regulating cell cycle induction. However, to avoid potential off-target effects of a small molecule [38][39][40][41] , we preferred to continue studying the role of LTCC in cell cycle induction through manipulating its activity using RRAD overexpression. The direct genetic manipulation of LTCC was not possible as genetic deletions of the LTCC α1C or the β2 encoding genes result in embryonic lethality with heart dysfunction 42,43 .…”