Recent Developments in the Determination of PM2.5 Chemical Composition

MicroRNA miR-212-5p Regulates the MEK/ERK Signaling Pathway by Targeting A-Raf proto-oncogene serine/threonine-protein kinase (ARAF) to Regulate Cowshed PM2.5-Induced NR8383 Apoptosis

Objective: To investigate the role of miR-212-5p-targeted ARAF during the apoptosis of rat alveolar macrophages induced by cowshed PM2.5. Methods: miRNA and related target genes and pathways were predicted using the KEGG, TargetScan, and other prediction websites. NR8383 macrophages were treated with cowshed PM2.5 to establish an in vitro lung injury model in rats; meanwhile, for the assessment of cell viability, apoptosis, intracellular calcium ions, and mitochondrial membrane potential in NR8383 cells, RT-qPCR was used to detect the expression of miR-212-5p and the target gene ARAF. Results: The bioinformatic analyses showed that miR-212-5p and ARAF were involved in PM2.5-associated cellular damage. Exposure to different concentrations (0 μg/mL, 60 μg/mL, 180 μg/mL, 300 μg/mL) with different durations (0 h, 12 h, 24 h, 48 h) of cowshed PM2.5 resulted in apoptosis, increased intracellular calcium ions, and decreased mitochondrial membrane potential. The miR-212-5p mimic group showed an up-regulation of Bax and cleaved Caspase 3 expression but decreased Bcl2 expression compared to the NC group, and overexpression of ARAF up-regulated the expression of p-MEK1/2 and p-ERK1/2 and simultaneously reversed the above phenomena. Conclusions: miR-212-5p targets ARAF to affect the cowshed PM2.5-induced apoptosis through the MEK/ERK signaling pathway, providing a potential target for relevant farming industry and pathology studies.

Unique regulatory roles of ncRNAs changed by PM2.5 in human diseases

PM_2.5 is a type of particulate matter with an aerodynamic diameter smaller than 2.5 µm, and exposure to PM_2.5 can adversely damage human health. PM_2.5 may impair health through oxidative stress, inflammatory reactions, immune function alterations and chromosome or DNA damage. Through increasing in-depth studies, researchers have found that noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs), circular RNAs (circRNAs) as well as long noncoding RNAs (lncRNAs), might play significant roles in PM_2.5-related human diseases via some of the abovementioned mechanisms. Therefore, in this review, we mainly discuss the regulatory function of ncRNAs altered by PM_2.5 in human diseases and summarize the potential molecular mechanisms. The findings reveal that these ncRNAs might induce or promote diseases via inflammation, the oxidative stress response, cell autophagy, apoptosis, cell junction damage, altered cell proliferation, malignant cell transformation, disruption of synaptic function and abnormalities in the differentiation and status of immune cells. Moreover, according to a bioinformatics analysis, the altered expression of potential genes caused by these ncRNAs might be related to the development of some human diseases. Furthermore, some ncRNAs, including lncRNAs, miRNAs and circRNAs, or processes in which they are involved may be used as biomarkers for relevant diseases and potential targets to prevent these diseases. Additionally, we performed a meta-analysis to identify more promising diagnostic ncRNAs as biomarkers for related diseases.

Toxic External Exposure Leading to Ocular Surface Injury

The surface of the eye is directly exposed to the external environment, protected only by a thin tear film, and may therefore be damaged by contact with ambient particulate matter, liquids, aerosols, or vapors. In the workplace or home, the eye is subject to accidental or incidental exposure to cleaning products and pesticides. Organic matter may enter the eye and cause infection. Ocular surface damage can trigger a range of symptoms such as itch, discharge, hyperemia, photophobia, blurred vision, and foreign body sensation. Toxin exposure can be assessed clinically in multiple ways, including via measurement of tear production, slit-lamp examination, corneal staining, and conjunctival staining. At the cellular level, environmental toxins can cause oxidative damage, apoptosis of corneal and conjunctival cells, cell senescence, and impaired motility. Outcomes range from transient and reversible with complete healing to severe and sight-compromising structural changes. Classically, evaluation of tolerance and safety was carried out using live animal testing; however, new in vitro and computer-based, in silico modes are superseding the gold standard Draize test. This review examines how environmental features such as pollutants, temperature, and seasonality affect the ocular surface. Chemical burns to the eye are considered, and approaches to protect the ocular surface are detailed.

Cell-free circulating mitochondrial DNA: An emerging biomarker for airborne particulate matter associated with cardiovascular diseases

The association of airborne particulate matter exposure with the deteriorating function of the cardiovascular system is fundamentally driven by the impairment of mitochondrial-nuclear crosstalk orchestrated by aberrant redox signaling. The loss of delicate balance in retrograde communication from mitochondria to the nucleus often culminates in the methylation of the newly synthesized strand of mitochondrial DNA (mtDNA) through DNA methyl transferases. In highly metabolic active tissues such as the heart, mtDNA's methylation state alteration impacts mitochondrial bioenergetics. It affects transcriptional regulatory processes involved in biogenesis, fission, and fusion, often accompanied by the integrated stress response. Previous studies have demonstrated a paradoxical role of mtDNA methylation in cardiovascular pathologies linked to air pollution. A pronounced alteration in mtDNA methylation contributes to systemic inflammation, an etiological determinant for several co-morbidities, including vascular endothelial dysfunction and myocardial injury. In the current article, we evaluate the state of evidence and examine the considerable promise of using cell-free circulating methylated mtDNA as a predictive biomarker to reduce the more significant burden of ambient air pollution on cardiovascular diseases.

Effects of Air Pollution on Cellular Senescence and Skin Aging

The human skin is exposed daily to different environmental factors such as air pollutants and ultraviolet (UV) light. Air pollution is considered a harmful environmental risk to human skin and is known to promote aging and inflammation of this tissue, leading to the onset of skin disorders and to the appearance of wrinkles and pigmentation issues. Besides this, components of air pollution can interact synergistically with ultraviolet light and increase the impact of damage to the skin. However, little is known about the modulation of air pollution on cellular senescence in skin cells and how this can contribute to skin aging. In this review, we are summarizing the current state of knowledge about air pollution components, their involvement in the processes of cellular senescence and skin aging, as well as the current therapeutic and cosmetic interventions proposed to prevent or mitigate the effects of air pollution in the skin.