Intermedin alleviates pathological cardiac remodeling by upregulating klotho

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Peptide Signaling

Background:

• Cardiac remodeling, characterized by hypertrophy, fibrosis, and dysfunction, is a precursor to heart failure.
• Intermedin (IMD), a peptide hormone, exhibits protective effects in cardiovascular diseases.
• Understanding the precise mechanisms of IMD in pathological cardiac remodeling is crucial for therapeutic development.

Purpose of the Study:

• To elucidate the role of Intermedin (IMD) in pathological cardiac remodeling.
• To investigate the underlying molecular mechanisms by which IMD exerts its cardioprotective effects.
• To explore the relationship between IMD, klotho, and key signaling pathways in cardiac hypertrophy.

Main Methods:

• Establishment of pathological cardiac remodeling mouse models (abdominal aorta constriction, Angiotensin II infusion).
• Utilized IMD-overexpression and IMD-knockout mouse models, alongside klotho-knockdown models.
• Employed techniques including Western blot, real-time PCR, histology, echocardiography, and in vitro cardiomyocyte studies.

Main Results:

• IMD deficiency exacerbated cardiac remodeling, while IMD overexpression alleviated it, correlating with klotho expression.
• IMD mitigated Angiotensin II-induced hypertension and cardiac hypertrophy, effects blocked by klotho knockdown.
• IMD inhibited CaMKII phosphorylation and calcineurin activity, mediated by klotho upregulation possibly via the PPARγ pathway.

Conclusions:

• Endogenous IMD plays a protective role against pathological cardiac remodeling.
• IMD upregulates klotho, subsequently inhibiting calcineurin and p-CaMKII, thereby preventing cardiac hypertrophy.
• IMD, acting through the PPARγ-klotho axis, represents a promising therapeutic target for heart disease.