Update on Silicosis

Ingenol ameliorates silicosis via targeting the PTGS2/PI3K/AKT signaling axis: Implications for therapeutic intervention

Silicosis, formerly known as silico, is an irreversible disease caused by prolonged inhalation of substantial amounts of free crystalline silica dust, characterized by pulmonary inflammation and extensive nodular fibrosis. The etiology of the disease remains unclear, which currently hinders the development of effective therapeutic drugs and interventions. Ingenol (Ing), a terpenoid active ingredient found in plants of the Euphorbiaceae family, including the entire herb of Euphorbia helioscopia, Euphorbia kansui, or Euphorbia lathyris, demonstrates significant anti-inflammatory and antiviral activities. In this study, we identified and confirmed that Ingenol can significantly ameliorate silicosis induced by silica dioxide by inhibiting the PTGS2/PI3K/AKT signaling pathway. In vivo, Ingenol improves pulmonary respiratory function and reduces inflammation and fibrosis in a murine model of CS-induced silicosis. In vitro, Ingenol inhibits the expression of cellular factors associated with inflammation and fibrosis, as well as macrophage apoptosis and fibroblast migration. Furthermore, it can modulate the expression of fibrosis-related proteins, thereby inhibiting CS-induced fibrotic responses. Mechanistically, a combination of bioinformatics, network pharmacology, and experimental validation indicates that Ingenol mitigates the progression of silicosis by modulating the PTGS2/PI3K/AKT signaling pathway. In summary, these findings suggest that Ingenol is a potential candidate for the treatment of silicosis.

Auricularia auricula polysaccharides alleviate experimental silicosis by targeting EGFR through the "gut-lung axis"

Silicosis is a major public health problem and remains a challenge for clinicians. There is an urgent need to find new drugs to minimize disease progression and deterioration. Auricularia auricula-juade is a traditional folk medicine that is used for nourishing lung functions. The aim of this study is to investigate the pharmacological action and potential mechanism of polysaccharides in Auricularia auricula for silicosis treatment. The results indicated that the Auricularia auricula polysaccharide (AAP) effectively improved silicosis induced by silica (SiO2) in mice. The preliminary screening of differentially expressed proteins (DEPs) in the lung and intestinal tissues after AAP intervention was performed using tandem mass tag (TMT) quantitative proteomics. A common differential protein of the intestine and lungs, i.e., epidermal growth factor receptor (EGFR), was focused on using a combination of current proteomics data and a network disease database. After further validation, the use of an intestinal-lung co-culture model confirmed that AAP had the ability to attenuate the secretion of EGFR ligands (i.e., TGF-α, EGF and AREG) and modulate signaling between the intestine and lungs. This effectively inhibited the EGFR/JNK signaling pathway in lung tissues, thereby achieving therapeutic efficacy against silicosis. This study provides a solid experimental foundation of the use of AAP for silicosis treatment.

Systematic review of the epidemiological evidence of associations between quantified occupational exposure to respirable crystalline silica and the risk of silicosis and lung cancer

Introduction

Occupational exposure to respirable crystalline silica (RCS) has been associated with both silicosis and lung cancer, but no systematic review (SR) specifically focused on exposure-response relationships has been published for these diseases.

Methods

We conducted this SR in compliance with Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. PubMed searches, supplemented with Web of Science and Google Scholar searches, identified 1,007 potentially relevant articles. After applying selection criteria and removing duplicates, 65 publications were reviewed and evaluated, 20 of which presented at least semi-quantitative exposure-response results for lung cancer (n = 12) and/or silicosis (n = 10).

Results

Cumulative RCS exposure was most commonly reported. Increasing silicosis risk with increasing cumulative RCS exposure was reported in all studies, with exposure thresholds indicated, but at different cumulative exposures. For most studies defining silicosis as International Labor Organization (ILO) score ≥ 1/0, substantially increased risks were clear at or above 1 mg-/m3-yr. For lung cancer, exposure-response estimates were mixed with 4 studies reporting no statistically significantly increased relative risk of lung cancer at any cumulative RCS exposure. Three studies reported statistically significant increased risks but only for high cumulative RCS exposures. Residual confounding by smoking was not explicitly discussed in most studies. One case-control study presented an exposure-response analysis for silica and lung cancer limited to never-smokers with substantial silica exposure; risk was increased only among those in the highest RCS exposure category. Studies with more detailed smoking information generally reported risks close to background levels except at the highest cumulative RCS exposure categories.

Conclusion

Silicosis risk clearly and consistently was increased above cumulative exposure thresholds of roughly 1 mg/m3-years across most studies. However, for lung cancer, results were heterogeneous with potential residual confounding by smoking complicating interpretation. Results suggest that lung cancer risk may not be increased at cumulative RCS exposures below the reported exposure thresholds for silicosis risk.

Evaluation of Silver Recovery from High-Sulphur Mining Waste Using Thiourea-Oxalate System

Mine tailings are a byproduct of mineral extraction and often pose an environmental challenge due to the contamination of soil and water bodies with dissolved metals. However, this type of waste offers the opportunity for the recovery of valuable metals such as silver (Ag). In the present investigation, an integral analysis of a sample of tailings was carried out, addressing granulometry, elemental composition, neutralization potential (NP), and acid potential (AP), as well as mineralogy, for the dissolution of silver from this type of waste. For this purpose, thiourea (CH4N2S) was used as a leaching agent due to its low toxicity, and potassium oxalate (K2C2O4) was used as an organic additive to improve the leaching of the silver phases (argentite and polybasite) present in the tailings. The effects of CH4N2S and K2C2O4 concentrations, temperature, and pH on the leaching efficiency of silver (Ag), copper (Cu), iron (Fe), and arsenic (As) were systematically studied. The results revealed that the maximum silver dissolution rate reached 90.75% under optimal conditions: 0.2 M L-1 of thiourea and 0.2 M L-1 of potassium oxalate, at 35 °C and a pH of 2.

Toxic effect and mRNA mechanism of moon dust simulant induced pulmonary inflammation in rats

Moon dust presents a significant hazard to manned moon exploration missions, yet our understanding of its toxicity remains limited. The objective of this study is to investigate the pattern and mechanism of lung inflammation induced by subacute exposure to moon dust simulants (MDS) in rats. SD rats were exposed to MDS and silica dioxide through oral and nasal inhalation for 6 hours per day continuously for 15 days. Pathological analysis indicated that the toxicity of MDS was lower than that of silica dioxide. MDS led to a notable recruitment and infiltration of macrophages in the rat lungs. Material characterization and biochemical analysis revealed that SiO2, Fe2O3, and TiO2 could be crucial sources of MDS toxicity. The study revealed that MDS-induced oxidative stress response can lead to pulmonary inflammation, which potentially may progress to lung fibrosis. Transcriptome sequencing revealed that MDS suppresses the PI3K-AKT signaling pathway, triggers the Tnfr2 non-classical NF-kB pathway and IL-17 signaling pathway, ultimately causing lung inflammation and activating predominantly antioxidant immune responses. Moreover, the study identified the involvement of upregulated genes IL1b, csf2, and Sod2 in regulating immune responses in rat lungs, making them potential key targets for preventing pulmonary toxicity related to moon dust exposure. These findings are expected to aid in safeguarding astronauts against the hazardous effects of moon dust and offer fresh insights into the implications and mechanisms of moon dust toxicity.