PM2.5 exposure inducing ATP alteration links with NLRP3 inflammasome activation

Impact of climate change on immune responses and barrier defense

Climate change is not just jeopardizing the health of our planet but is also increasingly affecting our immune health. There is an expanding body of evidence that climate-related exposures such as air pollution, heat, wildfires, extreme weather events, and biodiversity loss significantly disrupt the functioning of the human immune system. These exposures manifest in a broad range of stimuli, including antigens, allergens, heat stress, pollutants, microbiota changes, and other toxic substances. Such exposures pose a direct and indirect threat to our body's primary line of defense, the epithelial barrier, affecting its physical integrity and functional efficacy. Furthermore, these climate-related environmental stressors can hyperstimulate the innate immune system and influence adaptive immunity-notably, in terms of developing and preserving immune tolerance. The loss or failure of immune tolerance can instigate a wide spectrum of noncommunicable diseases such as autoimmune conditions, allergy, respiratory illnesses, metabolic diseases, obesity, and others. As new evidence unfolds, there is a need for additional research in climate change and immunology that covers diverse environments in different global settings and uses modern biologic and epidemiologic tools.

Hypermethylation of PPARG-encoding gene promoter mediates fine particulate matter-induced pulmonary fibrosis by regulating the HMGB1/NLRP3 axis

The inflammatory response induced by fine particulate matter (PM2.5), a common class of air pollutants, is an important trigger for the development of pulmonary fibrosis. However, the specific mechanisms responsible for this phenomenon are yet to be fully understood. To investigate the mechanisms behind the onset and progression of lung fibrosis owing to PM2.5 exposure, both rats and human bronchial epithelial cells were subjected to varying concentrations of PM2.5. The involvement of the PPARG/HMGB1/NLRP3 signaling pathway in developing lung fibrosis caused by PM2.5 was validated through the utilization of a PPARG agonist (rosiglitazone), a PPARG inhibitor (GW9662), and an HMGB1 inhibitor (glycyrrhizin). These outcomes highlighted the downregulation of PPARG expression and activation of the HMGB1/NLRP3 signaling pathway triggered by PM2.5, thereby eliciting inflammatory responses and promoting pulmonary fibrosis. Additionally, PM2.5 exposure-induced DNA hypermethylation of PPARG-encoding gene promoter downregulated PPARG expression. Moreover, the DNA methyltransferase inhibitor 5-azacytidine mitigated the hypermethylation of the PPARG-encoding gene promoter triggered by PM2.5. In conclusion, the HMGB1/NLRP3 signaling pathway was activated in pulmonary fibrosis triggered by PM2.5 through the hypermethylation of the PPARG-encoding gene promoter.

Protective Effect of Lonicera japonica on PM2.5-Induced Pulmonary Damage in BALB/c Mice via the TGF-β and NF-κB Pathway

This study aimed to assess the protective effect of an extract of Lonicera japonica against particulate-matter (PM)_2.5-induced pulmonary inflammation and fibrosis. The compounds with physiological activity were identified as shanzhiside, secologanoside, loganic acid, chlorogenic acid, secologanic acid, secoxyloganin, quercetin pentoside, and dicaffeoyl quinic acids (DCQA), including 3,4-DCQA, 3,5-DCQA, 4,5-DCQA, and 1,4-DCQA using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS^E). The extract of Lonicera japonica reduced cell death, reactive oxygen species (ROS) production, and inflammation in A549 cells. The extract of Lonicera japonica decreased serum T cells, including CD4⁺ T cells, CD8⁺ T cells, and total T helper 2 (Th2) cells, and immunoglobulins, including immunoglobulin G (IgG) and immunoglobulin E (IgE), in PM_2.5-induced BALB/c mice. The extract of Lonicera japonica protected the pulmonary antioxidant system by regulating superoxide dismutase (SOD) activity, reduced glutathione (GSH) contents, and malondialdehyde (MDA) levels. In addition, it ameliorated mitochondrial function by regulating the production of ROS, mitochondrial membrane potential (MMP), and ATP contents. Moreover, the extract of Lonicera japonica exhibited a protective activity of apoptosis, fibrosis, and matrix metalloproteinases (MMPs) via TGF-β and NF-κB signaling pathways in lung tissues. This study suggests that the extract of Lonicera japonica might be a potential material to improve PM_2.5-induced pulmonary inflammation, apoptosis, and fibrosis.

The Potential Benefits of Quercetin for Brain Health: A Review of Anti-Inflammatory and Neuroprotective Mechanisms

Neuroinflammation is a critical factor in developing and progressing numerous brain diseases, including neurodegenerative diseases. Chronic or excessive neuroinflammation can lead to neurotoxicity, causing brain damage and contributing to the onset and progression of various brain diseases. Therefore, understanding neuroinflammation mechanisms and developing strategies to control them is crucial for treating brain diseases. Studies have shown that neuroinflammation plays a vital role in the progression of neurodegenerative diseases, such as Alzheimer's (AD) and Parkinson's (PD), and stroke. Additionally, the effects of PM2.5 pollution on the brain, including neuroinflammation and neurotoxicity, are well-documented. Quercetin is a flavonoid, a plant pigment in many fruits, vegetables, and grains. Quercetin has been studied for its potential health benefits, including its anti-inflammatory, antioxidant, and anti-cancer properties. Quercetin may also have a positive impact on immune function and allergy symptoms. In addition, quercetin has been shown to have anti-inflammatory and neuroprotective properties and can activate AMP-activated protein kinase (AMPK), a cellular energy sensor that modulates inflammation and oxidative stress. By reducing inflammation and protecting against neuroinflammatory toxicity, quercetin holds promise as a safe and effective adjunctive therapy for treating neurodegenerative diseases and other brain disorders. Understanding and controlling the mechanisms of NF-κB and NLRP3 inflammasome pathways are crucial for preventing and treating conditions, and quercetin may be a promising tool in this effort. This review article aims to discuss the role of neuroinflammation in the development and progression of various brain disorders, including neurodegenerative diseases and stroke, and the impact of PM2.5 pollution on the brain. The paper also highlights quercetin's potential health benefits and anti-inflammatory and neuroprotective properties.

Effects of Streamer Discharge on PM2.5 Containing Endotoxins and Polyaromatic Hydrocarbons and Their Biological Responses In Vitro

Experimental and epidemiological studies have demonstrated that fine particulate matter with a diameter of <2.5 μm (PM2.5) affects both the respiratory and immune systems. However, effective approaches to reduce PM2.5-induced hazardous effects have not been discovered yet. Streamer discharge is a category of plasma discharge in which high-speed electrons collide with oxygen and nitrogen molecules. Although streamer discharge can reportedly eliminate bacteria, molds, chemical substances, and allergens, its ability to decontaminate PM2.5 has not been previously demonstrated. The present study explored whether streamer discharge treatment could reduce PM2.5-induced inflammatory responses by employing an in vitro system. PM2.5 was collected under four conditions (Bangkok (Sep.−Dec.), Bangkok (Dec.−Mar.), Singapore, and Taipei). Airway epithelial cells and antigen-presenting cells exposed to non-treated PM2.5 in several conditions resulted in inflammatory responses. Streamer-discharged PM2.5 (Bangkok (Sep.−Dec.)) decreased the expression of interleukin (IL)-6 and IL-8 compared to non-treated PM2.5. Moreover, composition analysis demonstrated that streamer discharge reduced some compounds, such as endotoxins and polycyclic aromatic hydrocarbons, included in PM2.5 that can elicit inflammatory responses. Streamer discharge treatment can reduce endotoxins, polycyclic aromatic hydrocarbons, and the subsequent inflammatory responses induced by PM2.5 in vitro.

Particulate matter in COPD pathogenesis: an overview

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder with substantial patient burden and leading cause of death globally. Cigarette smoke remains to be the most recognised causative factor behind COPD pathogenesis. Given the alarming increase in prevalence of COPD amongst non-smokers in recent past, a potential role of air pollution particularly particulate matter (PM) in COPD development has gained much attention of the scientists. Indeed, several epidemiological studies indicate strong correlation between airborne PM and COPD incidence/exacerbations. PM-induced oxidative stress seems to be the major player in orchestrating COPD inflammatory cycle but the exact molecular mechanism(s) behind such a process are still poorly understood. This may be due to the complexity of multiple molecular pathways involved. Oxidative stress-linked mitochondrial dysfunction and autophagy have also gained importance and have been the focus of recent studies regarding COPD pathogenesis. Accordingly, the present review is aimed at understanding the key molecular players behind PM-mediated COPD pathogenesis through analysis of various experimental studies supported by epidemiological data to identify relevant preventive/therapeutic targets in the area.