The Emerging Role of TR𝜶1 in Cardiac Repair: Potential Therapeutic Implications

Figure 2

Thyroid hormone (TH) determines the growth response to stress. Stress induced (by PE, a growth stimulus) overexpression of TRα1 in neonatal cardiomyocytes resulted in pathologic growth with dominant beta-MHC expression only in the absence of TH in the cultured medium (PE-T3) (B). This response was abolished after PD98059 administration (an ERK inhibitor) which prevents PE induced TRα1 accumulation in nucleus (PE-T3 + PD) (C). In the presence of TH in cultured medium, PE induced TRα1 accumulation in nucleus resulted in physiologic growth with suppressed beta-MHC and increased alpha-MHC (PE + T3) (D) *𝑃<0.05 versus A, **𝑃<0.05 versus B, ^#𝑃<0.05 versus A, B, and C, PE = phenylephrine, MHC = myosin heavy chain.