N6-methyladenosine-dependent primary microRNA-126 processing activated PI3K-AKT-mTOR pathway drove the development of pulmonary fibrosis induced by nanoscale carbon black particles in rats

The pulmonary fibrosis could be caused by long-term inhalation of carbon black (CB) particles. Studies on the mechanisms of pulmonary fibrosis induced by CB are required to develop the stratagem of prevention and treatment on fibrosis. The RNA-binding protein DiGeorge syndrome critical region gene 8 (DGCR8)-dependent pri-miRNAs processing is regulated by N⁶-methyladenosine (m⁶A) modification, which targets the downstream signal pathway. However, its role in pulmonary fibrosis has not been known clearly. In the present study, rats inhaled CB at dose of 0, 5 or 30 mg/m³ for 28 days, 6 h/day, respectively. The rats inhaled CB at dose of 0 or 30 mg/m³ for 14 days, 28 days and 90 days, respectively. In vitro experiments, the normal human bronchial epithelial cell line (16HBE) was treated with CB (0, 50, 100 and 200 μg/mL) for 24 h. In vitro and vivo study, the levels of fibrosis indicators including α-SMA, vimentin, collagen-I and hydroxyproline in CB treatment groups statistically increased in dose- or time- dependent manners compared with the control. After CB treatment, PI3K-AKT-mTOR pathway was activated and regulated by miRNA-126. We found that both of m⁶A modifications of pri-miRNA-126 and its binding with DGCR8 were decreased after CB treatment, which resulted in the reduction of mature miRNA-126 accompanied by accumulation of unprocessed pri-miRNA-126. This work demonstrated that m⁶A modification of pri-miRNA-126 and its binding with DGCR8 decreases blocked miRNA-126 maturation, and then activated the PI3K/AKT/mTOR pathway, which drove the fibro genesis in the lung after CB exposure.

Carbon black induced pulmonary fibrosis through piR-713551/PIWIL4 targeting THBS2 signal pathway

Carbon black (CB) is a vital constituent of airborne pollutants, comprising diesel exhaust and fine particulate matter (PM2.5), as well as a prevalent manufacturing material. CB was known to cause pulmonary dysfunction and fibrosis. However, the detailed molecular mechanisms underlying fibrosis development are poorly understood. In this study, 18 C57BL/6 mice were randomized into two groups and exposed to CB and filtered air (FA) for 28 days, with 6 hr/day and 7 days per week exposure regimen, respectively. The human normal bronchial epithelial cell line (BEAS-2B) was subjected to CB treatment for 24 h in vitro, with CB concentrations in 0, 50, 100, and 200 µg/mL. Our study indicated that exposure to CB resulted in a reduction in lung function and the development of pulmonary fibrosis in mice. Furthermore, our results showed cytoskeleton rearrangement and epithelial-mesenchymal transition (EMT) phenotype in BEAS-2B cells were happened, after CB exposure. Subsequent studies revealed that elevated expression of THBS2 after CB primarily contributed to the development of pulmonary fibrosis. The research findings from both in vivo and in vitro studies provided evidence that piR-713551 was involved in CB exposure-induced EMT by targeting the THBS2 gene and activating the β-catenin pathway. Mechanically, piR-713551/PIWIL4 complex activated the THBS2 transcription by recruitment of histone demethyltransferase KDM4A to reduce H3K9me3 modification at the THBS2 gene promoter. Conclusively, our research showed that CB exposure could activate EMT and lead pulmonary fibrosis which was modulated by piR-713551/PIWIL4 targeting THBS2.

Bifunctional ZIF-8/carbon black modified MXene with honeycomb sandwich structure for simultaneous electrochemical sensing of hydroquinone and catechol

As widely used pharmaceuticals and personal care products (PPCPs), hydroquinone (HQ) and catechol (CC) pose a great threat to human beings and the environment due to their high toxicity and low biodegradability. Therefore, it is essential to detect them simultaneously and sensitively. In this study, a novel bifunctional ZIF-8/carbon black (CB) modified MXene (MXene/CB/ZIF-8/GCE) electrochemical sensor (ECS) based on a glassy carbon electrode (GCE) was constructed for simultaneous detection of HQ and CC by si-tu doping ZIF-8 on MXene/CB with a honeycomb sandwich structure. The unique morphology, structure and electrochemical properties of MXene/CB/ZIF-8 have been characterized by SEM, EDS, XRD, XPS, CV, EIS and DPV. CB was introduced into MXene with an unique accordion-like structure to prevent the buildup of MXene interlayers while enhancing its electrical conductivity, and ZIF-8 provided abundant adsorption active sites to facilitate charge and ion transport, and the three exerted a synergistic effect to form an excellent electrode material with ultra-large specific surface area and superior electrical conductivity. The results displayed that the constructed sensor exhibited outstanding sensing ability for the HQ and CC with a wide linear range (0.3-160.0 μM for HQ and 0.5-165.0 μM for CC) and low limits of detection (LODs) (0.0126 μM for HQ and 0.0082 μM for CC). Besides, the sensor had ideal anti-interference ability, reproducibility, and stability, and the simultaneous detection of HQ and CC in environmental water samples could be realized with satisfactory, which demonstrated great potential for monitoring ecological water samples in practice.