The decreased secretion of myofibroblasts-derived pro-hypertrophic factors (TGF-β, PDGF-A and PDGF-B) in mice with myofibroblast-specific Irx2 depletion in response to Ang II infusion might explain the improvement in cardiac hypertrophy and systolic function. The gene discussed is TGFB1; the disease is cardiac hypertrophy.