Interleukin-5-induced eosinophil population improves cardiac function after myocardial infarction

Area of Science:

• Cardiovascular Biology
• Immunology
• Regenerative Medicine

Background:

• Interleukin-5 (IL-5) is crucial for eosinophil (EOS) development and tissue repair.
• The role of IL-5 in cardiac repair following myocardial infarction (MI) remains largely unexplored.

Purpose of the Study:

• To investigate whether IL-5-induced eosinophils contribute to heart repair post-MI.
• To elucidate the underlying molecular mechanisms of IL-5's action in cardiac healing.

Main Methods:

• Myocardial infarction (MI) was induced in wild-type mice.
• IL-5 expression, infarct size, ejection fraction, and angiogenesis were assessed.
• Eosinophil expansion and macrophage polarization were analyzed post-IL-5 administration or depletion.
• In vitro co-culture experiments examined eosinophil-macrophage interactions and signaling pathways (IL-4, STAT6).

Main Results:

• IL-5 expression was elevated in the heart post-MI.
• IL-5 administration reduced infarct size, improved ejection fraction, and enhanced angiogenesis.
• IL-5 treatment led to increased eosinophil accumulation and CD206+ macrophage polarization in the infarcted myocardium.
• Eosinophils were shown to promote M2 macrophage polarization via the IL-4/STAT6 axis.

Conclusions:

• IL-5 plays a beneficial role in cardiac recovery after MI.
• IL-5 facilitates heart repair by promoting eosinophil accumulation and M2 macrophage polarization.
• The IL-4/STAT6 signaling pathway is critical for IL-5-mediated cardiac healing.