Participation of lipopolysaccharide in hyperplasic adipose expansion: Involvement of NADPH oxidase/ROS/p42/p44 MAPK-dependent Cyclooxygenase-2

Integrated approach to reducing polypharmacy in older people: exploring the role of oxidative stress and antioxidant potential therapy

Increased life expectancy, attributed to improved access to healthcare and drug development, has led to an increase in multimorbidity, a key contributor to polypharmacy. Polypharmacy is characterised by its association with a variety of adverse events in the older persons. The mechanisms involved in the development of age-related chronic diseases are largely unknown; however, altered redox homeostasis due to ageing is one of the main theories. In this context, the present review explores the development and interaction between different age-related diseases, mainly linked by oxidative stress. In addition, drug interactions in the treatment of various diseases are described, emphasising that the holistic management of older people and their pathologies should prevail over the individual treatment of each condition.

Silica Nanoparticles Shed Light on Intriguing Cellular Pathways in Human Tracheal Smooth Muscle Cells: Revealing COX-2/PGE2 Production through the EGFR/Pyk2 Signaling Axis

The use of manufactured silica nanoparticles (SiNPs) has become widespread in everyday life, household products, and various industrial applications. While the harmful effects of crystalline silica on the lungs, known as silicosis or chronic pulmonary diseases, are well understood, the impact of SiNPs on the airway is not fully explored. This study aimed to investigate the potential effects of SiNPs on human tracheal smooth muscle cells (HTSMCs). Our findings revealed that SiNPs induced the expression of cyclooxygenase-2 (COX-2) mRNA/protein and the production of prostaglandin E2 (PGE2) without causing cytotoxicity. This induction was transcription-dependent, as confirmed by cell viability assays and COX-2 luciferase reporter assays. Further analysis, including Western blot with pharmacological inhibitors and siRNA interference, showed the involvement of receptor tyrosine kinase (RTK) EGF receptor (EGFR), non-RTK Pyk2, protein kinase Cα (PKCα), and p42/p44 MAPK in the induction process. Notably, EGFR activation initiated cellular signaling that led to NF-κB p65 phosphorylation and translocation into the cell nucleus, where it bound and stimulated COX-2 gene transcription. The resulting COX-2 protein triggered PGE2 production and secretion into the extracellular space. Our study demonstrated that SiNPs mediate COX-2 up-regulation and PGE2 secretion in HTSMCs through the sequential activation of the EGFR/Pyk2/PKCα/p42/p44MAPKs-dependent NF-κB signaling pathway. Since PGE2 can have both physiological bronchodilatory and anti-inflammatory effects, as well as pathological pro-inflammatory effects, the increased PGE2 production in the airway might act as a protective compensatory mechanism and/or a contributing factor during airway exposure to SiNPs.