title: Deregulation of selective autophagy during aging and pulmonary fibrosis: the role of TGFβ1.
abstract: Aging constitutes a significant risk factor for fibrosis, and idiopathic pulmonary fibrosis (IPF) is characteristically associated with advancing age. We propose that age-dependent defects in the quality of protein and cellular organelle catabolism may be causally related to pulmonary fibrosis. Our research found that autophagy diminished with corresponding elevated levels of oxidized proteins and lipofuscin in response to lung injury in old mice and middle-aged mice compared to younger animals. More importantly, older mice expose to lung injury are characterized by deficient autophagic response and reduced selective targeting of mitochondria for autophagy (mitophagy). Fibroblast to myofibroblast differentiation (FMD) is an important feature of pulmonary fibrosis in which the profibrotic cytokine TGFβ1 plays a pivotal role. Promotion of autophagy is necessary and sufficient to maintain normal lung fibroblasts' fate. On the contrary, FMD mediated by TGFβ1 is characterized by reduced autophagy flux, altered mitophagy, and defects in mitochondrial function. In accord with these findings, PINK1 expression appeared to be reduced in fibrotic lung tissue from bleomycin and a TGFβ1-adenoviral model of lung fibrosis. PINK1 expression is also reduced in the aging murine lung and biopsies from IPF patients compared to controls. Furthermore, deficient PINK1 promotes a profibrotic environment. Collectively, this study indicates that an age-related decline in autophagy and mitophagy responses to lung injury may contribute to the promotion and/or perpetuation of pulmonary fibrosis. We propose that promotion of autophagy and mitochondrial quality control may offer an intervention against age-related fibrotic diseases.
authors.affiliation: Department of Medicine, Division of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Sciences Center, New Orleans, LA, 70112, USA.
authors.forename: Meredith L
authors.initials: ML
authors.lastname: Sosulski
authors.affiliation: Department of Medicine, Division of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Sciences Center, New Orleans, LA, 70112, USA.
authors.forename: Rafael
authors.initials: R
authors.lastname: Gongora
authors.affiliation: Department of Medicine, Division of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Sciences Center, New Orleans, LA, 70112, USA.
authors.forename: Svitlana
authors.initials: S
authors.lastname: Danchuk
authors.affiliation: Department of Medicine, Division of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Sciences Center, New Orleans, LA, 70112, USA.
authors.forename: Chunmin
authors.initials: C
authors.lastname: Dong
authors.affiliation: Department of Medicine, Division of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Sciences Center, New Orleans, LA, 70112, USA.
authors.forename: Fayong
authors.initials: F
authors.lastname: Luo
authors.affiliation: Department of Medicine, Division of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Sciences Center, New Orleans, LA, 70112, USA.
authors.forename: Cecilia G
authors.initials: CG
authors.lastname: Sanchez
mesh_terms: D000375:Aging; D000818:Animals; D001343:Autophagy; D002454:Cell Differentiation; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000166:cytology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism; D018384:Oxidative Stress; D011658:Pulmonary Fibrosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D053773:Transforming Growth Factor beta1
keywords: PINK1; TGFβ1; aging; autophagy; lung fibrosis; lung injury; mitophagy; resveratrol