Human albumin augmented airway inflammation induced by PM2.5 in NC/Nga mice

The impact of PM2.5 on lung function and chronic respiratory diseases: insights from genetic evidence

BACKGROUND

PM2.5 has been associated with various adverse health effects, particularly affecting lung function and chronic respiratory diseases. However, the genetic causality relationship between PM2.5 exposure and lung function as well as chronic respiratory diseases remains poorly understood.

METHOD

We conducted a two-sample Mendelian randomization analysis to investigate the causal impact of PM2.5 on lung function and chronic respiratory diseases. Instrumental variables were carefully selected, with significance thresholds (P < 5 × 10- 8), and linkage disequilibrium with an r2 value below 0.001. Additionally, SNPs with an F-statistic exceeding 10 were included to mitigate potential bias stemming from weak instrumental variables. The primary analytical approach employed the Inverse Variance Weighted method, supplemented by the Weighted Median, MR-Egger, Simple Model, and Weighted Model. Furthermore, pleiotropy and heterogeneity were evaluated through the MR-Egger intercept test and Cochrane's Q test, with a sensitivity analysis conducted using the leave-one-out method.

RESULTS

Eight SNPs significantly associated with PM2.5 exposure were identified as Instrumental variables. Mendelian randomization analysis revealed a significant causal association between PM2.5 exposure and lung function (FEV), with an OR of 0.7284 (95% CI: 0.5799-0.9150). Similarly, PM2.5 exposure demonstrated a substantial causal effect on asthma, with an OR of 1.5280 (95% CI: 1.0470-2.2299). However, no causal association was observed between PM2.5 exposure and chronic obstructive pulmonary disease, with an OR of 1.5176 (95% CI: 0.8294-2.7768).

CONCLUSION

These findings emphasize the necessity for continued research efforts in environmental health to develop effective strategies for the prevention and management of chronic respiratory diseases.

The beneficial effects of lupeol on particulate matter-mediated pulmonary inflammation

Particulate matter (PM) poses significant health risks, especially fine particles (PM2.5) that can cause severe lung injuries. Lupeol, a phytosterol from medicinal plants, has potential anti-cancer properties. This study investigated lupeol's protective effects against PM2.5-induced lung damage. Mice received lupeol following intratracheal PM2.5 exposure. Results showed lupeol reduced lung damage, lowered wet/dry (W/D) weight ratio, and suppressed increased permeability caused by PM2.5. Additionally, lupeol decreased plasma inflammatory cytokines, total protein concentration in bronchoalveolar lavage fluid (BALF), and PM2.5-induced lymphocyte proliferation. Lupeol also reduced expression of toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), and autophagy-related proteins microtubule-associated protein 1 A/1 B-light chain 3 (LC3) II and Beclin 1, while increasing phosphorylated mammalian target of rapamycin (mTOR) phosphorylation. These findings suggest lupeol's potential as a therapeutic agent for PM2.5-induced lung damage via modulation of the TLR4-MyD88 and mTOR-autophagy pathways.

Causal relationship between particulate matter and COVID-19 risk: A mendelian randomization study

Background

Observational studies have linked exposure to fine (PM2.5) and coarse (PM10) particulate matter air pollution with adverse COVID-19 outcomes, including higher incidence and mortality. However, some studies questioned the effect of air pollution on COVID-19 susceptibility, raising questions about the causal nature of these associations. To address this, a less biased method like Mendelian randomization (MR) is utilized, which employs genetic variants as instrumental variables to infer causal relationships in observational data.

Method

We performed two-sample MR analysis using public genome-wide association studies data. Instrumental variables correlated with PM2.5 concentration, PM2.5 absorbance, PM2.5-10 concentration and PM10 concentration were identified. The inverse variance weighted (IVW), robust adjusted profile score (RAPS) and generalized summary data-based Mendelian randomization (GSMR) methods were used for analysis.

Results

IVW MR analysis showed PM2.5 concentration [odd ratio (OR) = 3.29, 95% confidence interval (CI) 1.48-7.35, P-value = 0.0036], PM2.5 absorbance (OR = 5.62, 95%CI 1.98-15.94, P-value = 0.0012), and PM10 concentration (OR = 3.74, 95%CI 1.52-9.20, P-value = 0.0041) increased the risk of COVID-19 severity after Bonferroni correction. Further validation confirmed PM2.5 absorbance was associated with heightened COVID-19 severity (OR = 6.05, 95%CI 1.99-18.38, P-value = 0.0015 for RAPS method; OR = 4.91, 95%CI 1.65-14.59, P-value = 0.0042 for GSMR method) and hospitalization (OR = 3.15, 95%CI 1.54-6.47, P-value = 0.0018 for RAPS method). No causal links were observed between particulate matter exposure and COVID-19 susceptibility.

Conclusions

Our study established a causal relationship between smaller particle pollution, specifically PM2.5, and increased risk of COVID-19 severity and hospitalization. These findings highlight the importance of improving air quality to mitigate respiratory disease progression.

Functionalized protein microparticles targeting hACE2 as a novel preventive strategy for SARS-CoV-2 infection

The coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), resulting in a serious burden on public health and social economy worldwide. SARS-CoV-2 infection is mainly initialized in the nasopharyngeal cavity through the binding of viral spike (S) protein to human angiotensin-converting enzyme 2 (hACE2) receptors which are widely expressed in many human cells. Thus, blockade of the interaction between viral S protein and hACE2 receptor in the primary entry site is a promising prevention strategy for the management of COVID-19. Here we showed protein microparticles (PMPs) decorated with hACE2 could bind and neutralize SARS-CoV-2 S protein-expressing pseudovirus (PSV) and protect host cells from infection in vitro. In the hACE2 transgenic mouse model, administration of intranasal spray with hACE2-decorated PMPs markedly decreased the viral load of SARS-CoV-2 in the lungs though the inflammation was not attenuated significantly. Our results provided evidence for developing functionalized PMPs as a potential strategy for preventing emerging air-borne infectious pathogens, such as SARS-CoV-2 infection.

Toxicological Effects of Artificial Fine Particulate Matter in Rats through Induction of Oxidative Stress and Inflammation

Airborne fine particulate matter with an aerodynamic diameter equal to or smaller than 2.5 μm (abbreviated as PM_2.5) increases the risk of nasal lesions, but the underlying molecular mechanism has not been fully elucidated. In the atmosphere, the composition of PM_2.5 collected varies in physical and chemical properties, which affects its damage to human health. Thus, we constructed artificial PM_2.5 particles based on actual PM_2.5 and investigated the in vivo effects of artificial PM_2.5 exposure on the oxidative stress, inflammatory response, and nasal mucosa morphology of rats. The results showed that artificial PM_2.5 is comparable in composition ratio, size, and morphology to actual PM_2.5. This in vivo study indicated that artificial PM_2.5 exposure reduces total superoxide dismutase and glutathione peroxidase activities, elevates malondialdehyde content in the nasal mucosa, and induces increased levels of pro-inflammatory mediators, including interleukin-1, interleukin-6 and tumor necrosis factor-α. Our data shows that artificial PM_2.5 particles could be used for experimental study of PM_2.5 toxicology, ensuring that the physical and chemical properties of experimental PM_2.5 are relatively constant and allowing for repeatability of this research. Oxidative damage and inflammatory response may be the toxic mechanisms that cause nasal lesions after exposure to artificial PM_2.5.

PM2.5-induced pulmonary inflammation via activating of the NLRP3/caspase-1 signaling pathway

Particulate matter 2.5 (PM2.5)-induced pulmonary inflammation has become a public concern in recent years. In which, the activation of the NLRP3/caspase-1 pathway was closely related to the inflammatory response of various diseases. However, the promotion effect of the NLRP3/caspase-1 pathway on PM2.5-induced pulmonary inflammation remains largely unclear. Here, our data showed that PM2.5 exposure caused lung injury in the mice by which inflammatory cell infiltration occurred in lung and alveolar structure disorder. Meanwhile, the exposure of human bronchial epithelial cells (16HBE) to PM2.5 resulted in suppressed cell viability, as well as elevated cell apoptosis. Moreover, a higher level of inflammatory cytokine and activation of the NLRP3/caspase-1 pathway in PM2.5-induced inflammation mice models and 16HBE cells. Mechanistically, pretreatment with MCC950, a NLRP3/caspase-1 pathway inhibitor, prevented PM2.5-induced lung injury, inflammatory response, and the number of inflammatory cells in BALFs, as well as promoted cell viability and decreased inflammatory cytokine secretion. Collectively, our findings indicated that the NLRP3/caspase-1 pathway serves a vital role in the pathological changes of pulmonary inflammation caused by PM2.5 exposure. MCC950 was expected to be the therapeutic target of PM2.5 inhalation mediated inflammatory diseases.