Using ROS as a Second Messenger, NADPH Oxidase 2 Mediates Macrophage Senescence via Interaction with NF‐κB during Pseudomonas aeruginosa Infection

Abstract

Pseudomonas aeruginosa (PA) is one of the most prevalent pathogens that cause nosocomial infection in critical patients. However, the mechanisms underlying macrophage growth status and functional changes during PA infection are yet unknown. In the present study, NADPH oxidase, gp91phox (NOX2) mediated macrophage to senescence in a PAO1 colony-dependent manner. gp91phox might regulate the senescence process through mutual interaction with the NF-κB pathway. During infection, the overexpression or downregulation of gp91phox in macrophage could affect the nuclear activity of NF-κB p65, while the downregulation of NF-κB p65 led to a suppressed expression of gp91phox. Reactive oxygen species (ROS) served as the second messenger between both molecules as the ROS inhibitor, N-acetylcysteine (NAC), could partially restore these changes. Consequently, the level of ROS and inflammatory cytokines, including IL-6 and TNFα, elevated during PAO1 infection, and their production altered as a result of the genetic manipulation of gp91phox and NF-κB p65, as well as NAC treatment. Also, the senescent phenotypes, SA-β-gal staining and p16ink4a, changed after genetic manipulation with gp91phox and NF-κB p65 and NAC treatment. The capacity of phagocytosis in macrophages was decreased during senescence. In conclusion, PA directs the macrophage towards senescence, and senescent macrophages exhibit a decreased ability of phagocytosis. This process of senescence was regulated by the interactions between NADPH oxidase gp91phox and NF-κB p65 via ROS as a second messenger.

ROS Generation in Microglia: Understanding Oxidative Stress and Inflammation in Neurodegenerative Disease

“…Furthermore, pharmacological inhibition or genetic deletion of gp91 phox similarly reduces NFκB activation, further suggesting NFκB regulation is redox-sensitive and may be directly linked to NOX2 activity. This NOX2-NFκB interaction is corroborated in a Pseudomonas aeruginosa macrophage activation model [ 147 ]. Knockdown of gp91 phox or application of N -acetyl cysteine (the antioxidant, NAC) in infected macrophages reduced NFκB activation levels.…”

“…In neuroinflammatory research, the relationship between oxidative stress and inflammation is a central problem. The two are undoubtedly linked; however, it is not clear how ROS interact with glia to elicit an immune response, although this may involve reciprocal regulation between NOX2 and NFκB [ 147 ]. The mechanisms leading to ROS production and release by microglia have been explored, especially in CAA where NOX activation likely involves fibrin-related clotting factors and IL13 signalling [ 104 , 126 ].…”

Bifidobacterium lactis BB-12 Attenuates Macrophage Aging Induced by D-Galactose and Promotes M2 Macrophage Polarization

“…Macrophage, which is one of the important immune cells, plays a pivotal role in the regulation of the innate and acquired immune responses [4]. However, the present study showed that macrophages also experience changes due to aging and have an immense influence on immunosenescence [5]. The quantity of aging-related galactosidase-(SA-β-gal-) positive macrophages in the senescence accelerated-prone mice (SAPM8) is considerably larger than that in young mice, and CD36 expression levels and IL-10 level decrease in aging macrophages [6].…”

<p>Sputum Exosomal microRNAs Profiling Reveals Critical Pathways Modulated By Pseudomonas aeruginosa Colonization In Bronchiectasis</p>

“…Ageing of the immune system predisposed to infection of opportunistic pathogens such as PA 41. In turn, PA infection accelerated cell senescence via NF-κB signaling pathway, which further hampered the eradication of PA 42. Collectively, our findings provide some hints on the complex network underlying the pathogenesis of bronchiectasis associated with PA colonization.…”