Regulating heart repair with cardiac-specific T lymphocytes

Area of Science:

• Immunology
• Cardiology
• Autoimmunity

Background:

• Coronary artery occlusion leading to cardiac tissue necrosis is a prevalent and lethal sterile injury.
• Myocardial infarction (MI) involves sterile inflammation, but its impact on adaptive immune responses remains incompletely understood.

Purpose of the Study:

• To identify and characterize antigen-specific CD4+ T helper (Th) cells involved in the response to myocardial infarction (MI).
• To investigate the role of these T cells in cardiac repair following ischemic injury.

Main Methods:

• Identification and characterization of antigen-specific CD4+ Th cells in a mouse model of MI.
• Adoptive transfer of T cells with specificity to myosin heavy chain alpha (MYHCA) into infarcted mice.
• Assessment of T cell phenotype and evaluation of the cardioprotective healing response.

Main Results:

• Myosin heavy chain alpha (MYHCA) was identified as a dominant cardiac autoantigen.
• T cells specific to MYHCA acquired a regulatory T cell (Treg) phenotype upon transfer into infarcted mice.
• Adoptively transferred MYHCA-specific T cells mediated a cardioprotective healing response.

Conclusions:

• Acute ischemic heart injury promotes protective T cell autoimmunity, contrary to expectations.
• MYHCA-specific T cells, particularly those with a Treg phenotype, play a crucial role in cardiac repair post-MI.
• Strategies enhancing antigen-specific Treg responses may limit inflammation and promote cardiac healing after MI.