NADPH Oxidases and Aging Models of Lung Fibrosis

TGF-β signaling in health and disease

The TGF-β regulatory system plays crucial roles in the preservation of organismal integrity. TGF-β signaling controls metazoan embryo development, tissue homeostasis, and injury repair through coordinated effects on cell proliferation, phenotypic plasticity, migration, metabolic adaptation, and immune surveillance of multiple cell types in shared ecosystems. Defects of TGF-β signaling, particularly in epithelial cells, tissue fibroblasts, and immune cells, disrupt immune tolerance, promote inflammation, underlie the pathogenesis of fibrosis and cancer, and contribute to the resistance of these diseases to treatment. Here, we review how TGF-β coordinates multicellular response programs in health and disease and how this knowledge can be leveraged to develop treatments for diseases of the TGF-β system.

Mitochondria, Aging, and Cellular Senescence: Implications for Scleroderma

PURPOSE OF REVIEW

The etiology of systemic sclerosis (SSc), which is a rare immune-mediated inflammatory disease characterized by vascular damage and fibrosis, is still unknown. However, different intrinsic (genetics) and extrinsic (environmental) factors play a part in the progression of the disease. This review focuses on the role of aging, mitochondrial dysfunction, and senescence in SSc.

RECENT FINDINGS

Mitochondrial dysfunction and senescence have been linked to the age-related susceptibility to other interstitial lung diseases (ILD) such as idiopathic pulmonary fibrosis (IPF). SSc is not regarded as an age-related disease but does show a higher incidence of cardiac events, fibrosis, and mortality at older age. We provide an overview of the current status of the role of aging, mitochondrial dysfunction, and senescence in SSc. Further work is needed to validate some of these pathways in SSc and may allow for new therapeutic interventions focused on restoring mitochondrial homeostasis and the targeted removal of chronic-senescent cells.

Ovulation and ovarian wound healing are impaired with advanced reproductive age

Aging is associated with reduced tissue remodeling efficiency and increased fibrosis, characterized by excess collagen accumulation and altered matrix degradation. Ovulation, the process by which an egg is released from the ovary, is one of the most dynamic cycles of tissue wounding and repair. Because the ovary is one of the first organs to age, ovulation and ovarian wound healing is impaired with advanced reproductive age. To test this hypothesis, we induced superovulation in reproductively young and old mice and determined the numbers of eggs ovulated and corpora lutea (CLs), the progesterone producing glands formed post-ovulation. Reproductively old mice ovulated fewer eggs and had fewer CLs relative to young controls. Moreover, reproductively old mice exhibited a greater number of oocytes trapped within CLs and expanded cumulus oocyte complexes within unruptured antral follicles, indicative of failed ovulation. In addition, post-ovulatory tissue remodeling was compromised with age as evidenced by reduced CL vasculature, increased collagen, decreased hyaluronan, decreased cell proliferation and apoptosis, impaired wound healing capacity, and aberrant morphology of the ovarian surface epithelium (OSE). These findings demonstrate that ovulatory dysfunction is an additional mechanism underlying the age-related loss of fertility beyond the reduction of egg quantity and quality.