Surface properties of PM2.5 calcite fine particulate matter in the presence of same size bacterial cells and exocellular polymeric substances (EPS) of Bacillus mucitaginosus

Overview of PM2.5 and health outcomes: Focusing on components, sources, and pollutant mixture co-exposure

PM_2.5 varies in source and composition over time and space as a complicated mixture. Consequently, the health effects caused by PM_2.5 varies significantly over time and generally exhibit significant regional variations. According to numerous studies, a notable relationship exists between PM_2.5 and the occurrence of many diseases, such as respiratory, cardiovascular, and nervous system diseases, as well as cancer. Therefore, a comprehensive understanding of the effect of PM_2.5 on human health is critical. The toxic effects of various PM_2.5 components, as well as the overall toxicity of PM_2.5 are discussed in this review to provide a foundation for precise PM_2.5 emission control. Furthermore, this review summarizes the synergistic effect of PM_2.5 and other pollutants, which can be used to draft effective policies.

The association of PM2.5 with airway innate antimicrobial activities of salivary agglutinin and surfactant protein D

Fine particulate matter ≤2.5 μm (PM_2.5) is a prominent global public health risk factor that can cause respiratory infection by downregulating the amounts of antimicrobial proteins and peptides (AMPs). Both salivary agglutinin (SAG) and surfactant protein D (SPD) are important AMPs in respiratory mucosal fluid, providing protection against airway pathogen invasion and infection by inducing microbial aggregation and enhancing pathogen clearance. However, the relationship between PM_2.5 and these AMPs is unclear. To better understand the relationship between PM_2.5 and airway innate immune defenses, we review the respiratory antimicrobial activities of SAG and SPD, as well as the adverse effects of PM_2.5 on airway innate antimicrobial defense. We speculate there exists a dual effect between PM_2.5 and respiratory antimicrobial activity, which means that PM_2.5 suppresses respiratory antimicrobial activity through downregulating airway AMPs, while airway AMPs accelerate PM_2.5 clearance by inducing PM_2.5 microbial aggregation. We propose further research on the relationship between PM_2.5 and these AMPs.

Adverse Effects of Fine-Particle Exposure on Joints and Their Surrounding Cells and Microenvironment

Current understanding of the health risks and adverse effects upon exposure to fine particles is premised on the direct association of particles with target organs, particularly the lung; however, fine-particle exposure has also been found to have detrimental effects on sealed cavities distant to the portal-of-entry, such as joints. Moreover, the fundamental toxicological issues have been ascribed to the direct toxic mechanisms, in particular, oxidative stress and proinflammatory responses, without exploring the indirect mechanisms, such as compensated, adaptive, and secondary effects. In this Review, we recapitulate the current findings regarding the detrimental effects of fine-particle exposure on joints, the surrounding cells, and microenvironment, as well as their deteriorating impact on the progression of arthritis. We also elaborate the likely molecular mechanisms underlying the particle-induced detrimental influence on joints, not limited to direct toxicity, but also considering the other indirect mechanisms. Because of the similarities between fine air particles and engineered nanomaterials, we compare the toxicities of engineered nanomaterials to those of fine air particles. Arthritis and joint injuries are prevalent, particularly in the elderly population. Considering the severity of global exposure to fine particles and limited studies assessing the detrimental effects of fine-particle exposure on joints and arthritis, this Review aims to appeal to a broad interest and to promote more research efforts in this field.

Effects of Fine Particulate Matter on Pseudomonas aeruginosa Adhesion and Biofilm Formation In Vitro

Respiratory infections of Pseudomonas aeruginosa are a major cause of mortality and morbidity for hospitalized patients. Fine particulate matter (FPM) is known to have interactions with some bacterial infection in the respiratory system. In this report, we investigate the effect of different concentration of FPM on P. aeruginosa attachment and biofilm formation using in vitro cell culture systems. P. aeruginosa were cultured to form mature biofilms on hydroxyapatite-coated peg and the number of bacteria in the biofilms was enumerated. Morphology of biofilm was imaged with scanning electron microscopy and confocal laser scanning microscopy. Bacterial affinity change to the cell membrane was evaluated with attached colony counting and fluorescence microscopy images. Alteration of bacterial surface hydrophobicity and S100A4 protein concentration were explored as mechanisms of P. aeruginosa adhesion to human cells. There were a concentration-dependent increase of thickness and surface roughness of biofilm mass. P. aeruginosa adherence to respiratory epithelial cells was increased after FPM treatment. Bacterial surface hydrophobicity and S1000A4 protein concentration were increased with proportionally the dose of FPM in media. FPM in the airway could enhance both the adhesion of P. aeruginosa to epithelial cells and biofilm formation. Bacterial surface hydrophobicity and human cell plasma membrane injury are associated with binding of P. aeruginosa on airway epithelial cells and biofilm formation.