Chemical inhibition or genetic deletion of PARP1 arrested c-Fos- and JunB-mediated AP-1 transcriptional activation of MMP/TGF-β responses in Mφ, and this was beneficial in arresting the T. cruzi-driven cardiac fibroblast-to-myofibroblast differentiation in chronic CD. The gene discussed is FOSB; the disease is Cowden disease.