Smoking, aging, and expression of proteins related to the FOXO3 signaling pathway in lung tissues

Role of cellular senescence in inflammatory lung diseases

Cellular senescence, a characteristic sign of aging, classically refers to permanent cell proliferation arrest and is a vital contributor to the pathogenesis of cancer and age-related illnesses. A lot of imperative scientific research has shown that senescent cell aggregation and the release of senescence-associated secretory phenotype (SASP) components can cause lung inflammatory diseases as well. In this study, the most recent scientific progress on cellular senescence and phenotypes was reviewed, including their impact on lung inflammation and the contributions of these findings to understanding the underlying mechanisms and clinical relevance of cell and developmental biology. Within a dozen pro-senescent stimuli, the irreparable DNA damage, oxidative stress, and telomere erosion are all crucial in the long-term accumulation of senescent cells, resulting in sustained inflammatory stress activation in the respiratory system. An emerging role for cellular senescence in inflammatory lung diseases was proposed in this review, followed by the identification of the main ambiguities, thus further understanding this event and the potential to control cellular senescence and pro-inflammatory response activation. In addition, novel therapeutic strategies for the modulation of cellular senescence that might help to attenuate inflammatory lung conditions and improve disease outcomes were also presented in this research.

Organ-differential Roles of Akt/FoxOs Axis as a Key Metabolic Modulator during Aging

FoxOs and their post-translational modification by phosphorylation, acetylation, and methylation can affect epigenetic modifications and promote the expression of downstream target genes. Therefore, they ultimately affect cellular and biological functions during aging or occurrence of age-related diseases including cancer, diabetes, and kidney diseases. As known for its key role in aging, FoxOs play various biological roles in the aging process by regulating reactive oxygen species, lipid accumulation, and inflammation. FoxOs regulated by PI3K/Akt pathway modulate the expression of various target genes encoding MnSOD, catalases, PPARγ, and IL-1β during aging, which are associated with age-related diseases. This review highlights the age-dependent differential regulatory mechanism of Akt/FoxOs axis in metabolic and non-metabolic organs. We demonstrated that age-dependent suppression of Akt increases the activity of FoxOs (Akt/FoxOs axis upregulation) in metabolic organs such as liver and muscle. This Akt/FoxOs axis could be modulated and reversed by antiaging paradigm calorie restriction (CR). In contrast, hyperinsulinemia-mediated PI3K/Akt activation inhibited FoxOs activity (Akt/FoxOs axis downregulation) leading to decrease of antioxidant genes expression in non-metabolic organs such as kidneys and lungs during aging. These phenomena are reversed by CR. The results of studies on the process of aging and CR indicate that the Akt/FoxOs axis plays a critical role in regulating metabolic homeostasis, redox stress, and inflammation in various organs during aging process. The benefical actions of CR on the Akt/FoxOs axis in metabolic and non-metabolic organs provide further insights into the molecular mechanisms of organ-differential roles of Akt/FoxOs axis during aging.

The aging lung: Physiology, disease, and immunity

The population is aging at a rate never seen before in human history. As the number of elderly adults grows, it is imperative we expand our understanding of the underpinnings of aging biology. Human lungs are composed of a unique panoply of cell types that face ongoing chemical, mechanical, biological, immunological, and xenobiotic stress over a lifetime. Yet, we do not fully appreciate the mechanistic drivers of lung aging and why age increases the risk of parenchymal lung disease, fatal respiratory infection, and primary lung cancer. Here, we review the molecular and cellular aspects of lung aging, local stress response pathways, and how the aging process predisposes to the pathogenesis of pulmonary disease. We place these insights into context of the COVID-19 pandemic and discuss how innate and adaptive immunity within the lung is altered with age.