Neonatal Regulatory T Cells Mediate Fibrosis and Contribute to Cardiac Repair

Area of Science:

• Cardiovascular Biology
• Immunology
• Regenerative Medicine

Background:

• The adult heart has limited repair capacity post-myocardial infarction, unlike the neonatal heart.
• The role of T cell subsets in age-dependent cardiac repair is not well understood.

Purpose of the Study:

• To investigate the temporal activation of T cell subsets after myocardial injury in mice of different ages.
• To elucidate the contribution of T cells to immune homeostasis and myocardial repair.

Main Methods:

• Myocardial infarction induced in neonatal, adult, and aged mice.
• Flow cytometry and RNA sequencing to analyze T cell subsets (CD4+, CD8+, T-reg).
• Conditional knockout mouse model (Lck-cre; Rcn3fl/fl) to assess Rcn3 function in T cells.

Main Results:

• Neonatal hearts showed increased T cell subsets post-injury.
• Rcn3 identified as a neonatal-specific, injury-responsive gene in T-reg cells, promoting a reparative microenvironment.
• Rcn3 deletion in T cells impaired cardiac function recovery and increased fibrosis post-injury.

Conclusions:

• Neonatal T-reg cells are crucial for cardiac repair post-injury.
• Rcn3 plays a significant role in mediating the anti-fibrotic and reparative effects of T-reg cells.
• Rcn3 represents a potential therapeutic target for improving cardiac repair and reducing adverse remodeling in adult hearts.