RTP801 Amplifies Nicotinamide Adenine Dinucleotide Phosphate Oxidase-4-Dependent Oxidative Stress Induced by Cigarette Smoke

Cigarette Smoke-Induced Reactive Oxygen Species Formation: A Concise Review

Smoking is recognized as a significant risk factor for numerous disorders, including cardiovascular diseases, respiratory conditions, and various forms of cancer. While the exact pathogenic mechanisms continue to be explored, the induction of oxidative stress via the production of excess reactive oxygen species (ROS) is widely accepted as a primary molecular event that predisposes individuals to these smoking-related ailments. This review focused on how cigarette smoke (CS) promotes ROS formation rather than the pathophysiological repercussions of ROS and oxidative stress. A comprehensive analysis of existing studies revealed the following key ways through which CS imposes ROS burden on biological systems: (1) ROS, as well as radicals, are intrinsically present in CS, (2) CS constituents generate ROS through chemical reactions with biomolecules, (3) CS stimulates cellular ROS sources to enhance production, and (4) CS disrupts the antioxidant system, aggravating the ROS generation and its functions. While the evidence supporting these mechanisms is chiefly based on in vitro and animal studies, the direct clinical relevance remains to be fully elucidated. Nevertheless, this understanding is fundamental for deciphering molecular events leading to oxidative stress and for developing intervention strategies to counter CS-induced oxidative stress.

The role of ferroptosis-related genes in airway epithelial cells of asthmatic patients based on bioinformatics

It has been reported that airway epithelial cells and ferroptosis have certain effect on asthma. However, the action mechanism of ferroptosis-related genes in airway epithelial cells of asthmatic patients is still unclear. Firstly, the study downloaded the GSE43696 training set, GSE63142 validation set and GSE164119 (miRNA) dataset from the gene expression omnibus database. 342 ferroptosis-related genes were downloaded from the ferroptosis database. Moreover, differentially expressed genes (DEGs) between asthma and control samples in the GSE43696 dataset were screened by differential analysis. Consensus clustering analysis was performed on asthma patients to classify clusters, and differential analysis was performed on clusters to obtain inter-cluster DEGs. Asthma-related module was screened by weighted gene co-expression network analysis. Then, DEGs between asthma and control samples, inter-cluster DEGs and asthma-related module were subjected to venn analysis for obtaining candidate genes. The last absolute shrinkage and selection operator and support vector machines were respectively applied to the candidate genes to screen for feature genes, and functional enrichment analysis was performed. Finally, a competition endogenetic RNA network was constructed and drug sensitivity analysis was conducted. There were 438 DEGs (183 up-regulated and 255 down-regulated) between asthma and control samples. 359 inter-cluster DEGs (158 up-regulated and 201 down-regulated) were obtained by screening. Then, the black module was significantly and strongly correlated with asthma. The venn analysis yielded 88 candidate genes. 9 feature genes (NAV3, ITGA10, SYT4, NOX1, SNTG2, RNF182, UPK1B, POSTN, SHISA2) were screened and they were involved in proteasome, dopaminergic synapse etc. Besides, 4 mRNAs, 5 miRNAs, and 2 lncRNAs collectively formed competition endogenetic RNA regulatory network, which included RNF182-hsa-miR-455-3p-LINC00319 and so on. The predicted therapeutic drug network map contained NAV3-bisphenol A and other relationship pairs. The study investigated the potential molecular mechanisms of NAV3, ITGA10, SYT4, NOX1, SNTG2, RNF182, UPK1B, POSTN, SHISA2 in airway epithelial cells of asthmatic patients through bioinformatics analysis, providing a reference for the research of asthma and ferroptosis.

Redox Dysregulation in Aging and COPD: Role of NOX Enzymes and Implications for Antioxidant Strategies

With a rapidly growing elderly human population, the incidence of age-related lung diseases such as chronic obstructive pulmonary disease (COPD) continues to rise. It is widely believed that reactive oxygen species (ROS) play an important role in ageing and in age-related disease, and approaches of antioxidant supplementation have been touted as useful strategies to mitigate age-related disease progression, although success of such strategies has been very limited to date. Involvement of ROS in ageing is largely attributed to mitochondrial dysfunction and impaired adaptive antioxidant responses. NADPH oxidase (NOX) enzymes represent an important enzyme family that generates ROS in a regulated fashion for purposes of oxidative host defense and redox-based signalling, however, the associations of NOX enzymes with lung ageing or age-related lung disease have to date only been minimally addressed. The present review will focus on our current understanding of the impact of ageing on NOX biology and its consequences for age-related lung disease, particularly COPD, and will also discuss the implications of altered NOX biology for current and future antioxidant-based strategies aimed at treating these diseases.

Is REDD1 a metabolic double agent? Lessons from physiology and pathology

The Akt/mechanistic target of rapamycin (mTOR) signaling pathway governs macromolecule synthesis, cell growth, and metabolism in response to nutrients and growth factors. Regulated in development and DNA damage response (REDD)1 is a conserved and ubiquitous protein, which is transiently induced in response to multiple stimuli. Acting like an endogenous inhibitor of the Akt/mTOR signaling pathway, REDD1 protein has been shown to regulate cell growth, mitochondrial function, oxidative stress, and apoptosis. Recent studies also indicate that timely REDD1 expression limits Akt/mTOR-dependent synthesis processes to spare energy during metabolic stresses, avoiding energy collapse and detrimental consequences. In contrast to this beneficial role for metabolic adaptation, REDD1 chronic expression appears involved in the pathogenesis of several diseases. Indeed, REDD1 expression is found as an early biomarker in many pathologies including inflammatory diseases, cancer, neurodegenerative disorders, depression, diabetes, and obesity. Moreover, prolonged REDD1 expression is associated with cell apoptosis, excessive reactive oxygen species (ROS) production, and inflammation activation leading to tissue damage. In this review, we decipher several mechanisms that make REDD1 a likely metabolic double agent depending on its duration of expression in different physiological and pathological contexts. We also discuss the role played by REDD1 in the cross talk between the Akt/mTOR signaling pathway and the energetic metabolism.

The role of NOX4 in pulmonary diseases

Nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) is a subtype of the NOX family, which is mainly expressed in the pulmonary vasculature and pulmonary endothelial cells in the respiratory system. NOX4 has unique characteristics, and is a constitutively active enzyme that primarily produces hydrogen peroxide. The signaling pathways associated with NOX4 are complicated. Negative and positive feedback play significant roles in regulating NOX4 expression. The role of NOX4 is controversial because NOX4 plays a protective or damaging role in different respiratory diseases. This review summarizes the structure, enzymatic properties, regulation, and signaling pathways of NOX4. This review then introduces the roles of NOX4 in different diseases in the respiratory system, such as acute respiratory distress syndrome, chronic obstructive pulmonary disease, and pulmonary fibrosis.

Increased REDD1 facilitates neuronal damage after subarachnoid hemorrhage

Regulated in development and DNA damage responses 1 (REDD1) is a highly conserved stress-response protein and can be induced by hypoxia/ischemia and DNA damage. However, it is not known whether REDD1 involves in neuronal damage caused by subarachnoid hemorrhage (SAH) that is known as one of the most important causes of disability and death worldwide. Here, we first found that SAH markedly induced the increase of REDD1 (35.467 ng/ml) in cerebrospinal fluid (CSF) of patients at acute stage (within 24 h from bleeding) compared to that of control (0.644 ng/ml). And, REDD1 level was positively correlated with severity of brain injuries (Hunt-Hess grade of SAH), but it showed an obvious decline at recovery stage 6.201 ng/ml (before discharge from hospital) because of good recovery. Moreover, it was found that the expression of REDD1 was significantly induced by hemolysate in a dose-dependent way in neurons. Knockdown of REDD1 by lentivirus encoded REDD1-shRNA could inhibit the neuronal apoptosis and LDH leakage caused by hemolysate. Importantly, the level of REDD1 in peripheral blood of SAH patients was significantly higher (4.364 ng/ml) than that of healthy persons (1.317 ng/ml) and also was positively correlated with that in CSF. Taken together, our findings provide the novel and direct evidence that REDD1 could play a critical role of process of neuronal damage caused by SAH, suggesting a new molecular target to protect brain function from SAH injury.

Taurine Attenuates Calpain-2 Induction and a Series of Cell Damage via Suppression of NOX-Derived ROS in ARPE-19 Cells

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) are key transmembrane proteins leading to reactive oxygen species (ROS) overproduction. However, the detailed roles of NOXs in retinal pigment epithelial (RPE) cell metabolic stress induced by Earle's balanced salt solution (EBSS) through starvation remain unclear. In this study, we investigated what roles NOXs play in regard to calpain activity, endoplasmic stress (ER), autophagy, and apoptosis during metabolic stress in ARPE-19 cells. We first found that EBSS induced an increase in NOX2, NOX4, p22phox, and NOX5 compared to NOX1. Secondly, suppression of NOXs resulted in reduced ER stress and autophagy, decreased ROS generation, and alleviated cell apoptosis. Thirdly, silencing of NOX4, NOX5, and p22phox resulted in reduced levels of cell damage. However, silencing of NOX1 was unaffected. Finally, taurine critically mediated NOXs in response to EBSS stress. In conclusion, this study demonstrated for the first time that NOX oxidases are the upstream regulators of calpain-2, ER stress, autophagy, and apoptosis. Furthermore, the protective effect of taurine is mediated by the reduction of NOX-derived ROS, leading to sequential suppression of calpain induction, ER stress, autophagy, and apoptosis.

Treatment of Human Placental Choriocarcinoma Cells with Formaldehyde and Benzene Induced Growth and Epithelial Mesenchymal Transition via Induction of an Antioxidant Effect

Cigarette smoke (CS) causes about 480,000 deaths each year worldwide, and it is well-known to have harmful effects on the human body, leading to heart disease, stroke, lung cancer, and cardiovascular problems. In this study, the effects of formaldehyde (FA) and benzene (Bz), the main components of CS, on cell proliferation and epithelial mesenchymal transition (EMT) of JEG-3 human choriocarcinoma cells were examined to confirm the relationship between CS components and placenta carcinoma. Upon MTT assay, FA (10⁻⁸ M to 10⁻⁵ M) and Bz (10⁻¹¹ M to 10⁻⁸ M) increased JEG-3 cell proliferation. Western blot assay revealed that the protein expression of cyclin D1 and E1 increased, while the levels of p21 and p27 were reduced following treatment. In Scratch assay, FA (10⁻⁸ M and 10⁻⁵ M) and Bz (10⁻¹¹ M and 10⁻⁸ M) increased migration of JEG-3 cells at 24 h and 48 h compared with that at 0 h. In addition, the expression of the epithelial marker, E-cadherin, was significantly decreased, while the expression of the mesenchymal marker, N-cadherin, was significantly increased by FA (10⁻⁸ M and 10⁻⁵ M) and Bz (10⁻¹¹ M and 10⁻⁸ M). snail and slug transcriptional factors were associated with EMT, which were also up-regulated by FA and Bz, indicating that FA and Bz lead to an increase in the EMT process in JEG-3 choriocarcinoma cells. We further evaluated reactive oxygen species (ROS) and activation of antioxidant effect using dichlorofluorescin diacetate (DCFH-DA) and Western blot assay. FA and Bz increased the ROS production and an antioxidant related marker, Nrf2, in JEG-3 cells. However, eIF2α levels were reduced by FA and Bz via activation of the antioxidant reaction. Taken together, these results indicated that FA and Bz induce the growth and migration of human choriocarcinoma cells via regulation of the cell cycle and EMT and activation of ROS and antioxidant related markers.