title: TGF-β1 prevents simulated ischemia/reperfusion-induced cardiac fibroblast apoptosis by activation of both canonical and non-canonical signaling pathways.
abstract: Ischemia/reperfusion injury is a major cause of myocardial death. In the heart, cardiac fibroblasts play a critical role in healing post myocardial infarction. TGF-β1 has shown cardioprotective effects in cardiac damage; however, if TGF-β1 can prevent cardiac fibroblast death triggered by ischemia/reperfusion is unknown. Therefore, we test this hypothesis, and whether the canonical and/or non-canonical TGF-β1 signaling pathways are involved in this protective effect. Cultured rat cardiac fibroblasts were subjected to simulated ischemia/reperfusion. Cell viability was analyzed by trypan blue exclusion and propidium iodide by flow cytometry. The processing of procaspases 8, 9 and 3 to their active forms was assessed by Western blot, whereas subG1 population was evaluated by flow cytometry. Levels of total and phosphorylated forms of ERK1/2, Akt and Smad2/3 were determined by Western blot. The role of these signaling pathways on the protective effect of TGF-β1 was studied using specific chemical inhibitors. Simulated ischemia over 8h triggers a significant cardiac fibroblast death, which increased by reperfusion, with apoptosis actively involved. These effects were only prevented by the addition of TGF-β1 during reperfusion. TGF-β1 pretreatment increased the levels of phosphorylated forms of ERK1/2, Akt and Smad2/3. The inhibition of ERK1/2, Akt and Smad3 also blocked the preventive effects of TGF-β1 on cardiac fibroblast apoptosis induced by simulated ischemia/reperfusion. Overall, our data suggest that TGF-β1 prevents cardiac fibroblast apoptosis induced by simulated ischemia-reperfusion through the canonical (Smad3) and non canonical (ERK1/2 and Akt) signaling pathways.
authors: Centro Estudios Moleculares de la Célula, Facultad de Ciencias Químicas y Farmacéuticas/Facultad de Medicina, Universidad de Chile, Chile.
authors: Raúl
authors: R
authors: Vivar
authors: Claudio
authors: C
authors: Humeres
authors: Pedro
authors: P
authors: Ayala
authors: Ivonne
authors: I
authors: Olmedo
authors: Mabel
authors: M
authors: Catalán
authors: Lorena
authors: L
authors: García
authors: Sergio
authors: S
authors: Lavandero
authors: Guillermo
authors: G
authors: Díaz-Araya
mesh_terms: D000818:Animals; D017209:Apoptosis; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D020935:MAP Kinase Signaling System; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D009124:Muscle Proteins; D051899:Smad2 Protein; C497784:Smad2 protein, rat; D051900:Smad3 Protein; C497787:Smad3 protein, rat; D053773:Transforming Growth Factor beta1; D051057:Proto-Oncogene Proteins c-akt; D048052:Mitogen-Activated Protein Kinase 3