[Co-exposure of carbon black and cadmium induces autophagy and inflammation in human bronchial epithelial cells via PERK pathway].

Objective: To investigate the effects of carbon black and cadmium (Cd) combined exposure on autophagy and inflammatory response mediated by protein kinase R-like endoplasmic reticulum kinase (PERK) pathway in human bronchial epithelial (16HBE) cells. Methods: In January 2022, human bronchial epithelial (16HBE) cells were resuscitated and cultured. Carbon black nanoparticles (CBNPs) were oxidized to adsorb Cd ions to construct "CBNPs-Cd" complexes. CCK-8 assay was used to detect the effects of different concentrations and time combinations of CBNPs and Cd on the viability of 16HBE cells. The subsequent dose groups were exposed to 2 µg/ml Cd, 100 µg/ml CBNPs, 100 µg/ml CBNPs+2 µg/ml Cd for 24 h. The number of autophagosomes and autolysosomes was detected by transmission electron microscopy. Western blotting was used to detect the protein expressions of PERK, eukaryotic initiation factor 2α (eIf2α), activating transcription factor 4 (ATF4), sequestosome 1 (SQSTM1/P62), and microtubule-associated protein 1 light chain 3 (LC3). After PERK gene was silenced by siRNA technology, the changes of autophagy marker proteins P62 and LC3 were detected, and the expressions of inflammatory factors interleukin-6 (IL6) and interleukin-8 (IL8) were detected by fluorescence quantitative PCR technique. One-way ANOVA analysis was used to compare three groups or more. LSD test was used for comparison between two groups. Factorial analysis was used for multivariate component analysis. Results: There was no significant change in cell viability of 16HBE after 24 h exposure to CBNPs and Cd alone or combined (P>0.05). Compared with the control group, the expressions of P62 and LC3 in 16HBE cells were significantly increased in the CBNPs and Cd alone/combined exposure group (P<0.05), and the number of autophagosomes and autophagolysosomes in the combined exposure group was increased compared with other groups. Compared with the control group, CBNPs and Cd alone exposure group had no significant effects on p-PERK/PERK and p-eIf2α/eIf2α protein expression (P>0.05). However, the protein expressions of p-PERK/PERK and p-eIf2α/eIf2α and ATF4 were all increased in the combined exposure group (P<0.05), and the levels of IL6 and IL8 in 16HBE cells in the combined exposure group of CBNPs and Cd were significantly higher than those in the control group (P<0.05). The levels of LC3 protein, IL6 and IL8 were decreased in the CBNPs-Cd combined exposure group after knockdown of PERK gene (P<0.05). The results of factorial analysis showed that exposure to CBNPs and Cd had significant effects on the expression of P62, LC3 and IL6 (P<0.05), but the interaction between the two chemicals had no statistical significance (P>0.05) . Conclusion: CBNPs-Cd combined exposure may inhibit autophagy and increase inflammation in human bronchial epithelial cells through activation of PERK-eIf2α-ATF4 pathway.

[Expression profile of circular RNA in inflammatory response in human bronchial epithelial cells induced by carbon black nanoparticles].

Objective: To explore the toxic effect of carbon black nanoparticles on human bronchial epithelial cells, and identify the differentially expressed circular RNA based on the full transcriptome high-throughput sequencing, so as to provide evidence for the development of biomarkers exposed to carbon black nanoparticles and their application on epigenetic toxicology. Methods: In June 2020, 16 HBE cells were treated with carbon black nanoparticles at concentrations of 20, 40 and 80 µg/ml, and 16 HBE cells without any intervention were used as the control group. The cytotoxicity of carbon black nanoparticles was detected by CCK8 and LDH experiments. Real-time quantitative fluorescent PCR (qRT-PCR) and ELISA were used to detect the changes of interleukin-6 (IL-6) and interleukin-8 (IL-6, IL-8) mRNA and protein levels of carbon black nanoparticles with concentration gradient after 72 h exposure. Western blot analysis was conducted to detect the expression levels of toll-like receptor 4 (TLR4), phosphorylated nuclear factor-κB (P-NF-κB), apoptosis-related speckled protein (ASC) and Caspase-1 associated with nuclear factor-κB. According to high-throughput sequencing results, differentially expressed Circrnas were screened and identified by qRT-PCR, and those with stable differentially expressed circrnas and the strongest association with the NF-κB pathway were selected for ring performance identification. Results: After being exposed to carbon black nanoparticles for 72 h, the activity of 16HBE cells decreased significantly (P<0.05), and the release of lactate dehydrogenase increased significantly (P<0.05). Compared with control group, mRNA expression levels of IL-6 and IL-8, protein levels of IL-6 and IL-8 were increased, and protein levels of TLR4, p-NF-κB, ASC and Caspase-1 were significantly up-regulated in 16 HBE cells of different concentrations, with statistical significance (P<0.05). Compared with the control group, a total of 492 differentially expressed circular Rnas (|log2 FC|>1) were detected. Among the 5 differentially expressed (P<0.05) circular Rnas, circ_002642 was selected as the object of subsequent research on circular Rnas, affter 72 hours of exposure to 80 µg/ml CBNPs, 16HBE cells showed signlficantly higher expression of circ_002642 (P<0.05) . Conclusion: Carbon black nanoparticles can induce differentially expressed circular RNAs associated with inflammatory response in human bronchial epithelial cells.

Local negative permittivity and topological phase transition in polar skyrmions.

Topological solitons such as magnetic skyrmions have drawn attention as stable quasi-particle-like objects. The recent discovery of polar vortices and skyrmions in ferroelectric oxide superlattices has opened up new vistas to explore topology, emergent phenomena and approaches for manipulating such features with electric fields. Using macroscopic dielectric measurements, coupled with direct scanning convergent beam electron diffraction imaging on the atomic scale, theoretical phase-field simulations and second-principles calculations, we demonstrate that polar skyrmions in (PbTiO3)n/(SrTiO3)n superlattices are distinguished by a sheath of negative permittivity at the periphery of each skyrmion. This enhances the effective dielectric permittivity compared with the individual SrTiO3 and PbTiO3 layers. Moreover, the response of these topologically protected structures to electric field and temperature shows a reversible phase transition from the skyrmion state to a trivial uniform ferroelectric state, accompanied by large tunability of the dielectric permittivity. Pulsed switching measurements show a time-dependent evolution and recovery of the skyrmion state (and macroscopic dielectric response). The interrelationship between topological and dielectric properties presents an opportunity to simultaneously manipulate both by a single, and easily controlled, stimulus, the applied electric field.

Malondialdehyde and SOD-induced changes of gastric tissues in acute gastric mucosal injury under positive acceleration.

The aim of this study was to investigate the impacts of positive acceleration (+Gz) on the gastric mucosal tissues in cases of acute gastric mucosal injury and to explore the role of oxygen free radicals. Thirty Sprague Dawley rats were randomly divided into the absolute ethanol control group (A group), absolute ethanol +5Gz group (B group), absolute ethanol +10Gz group (C group). Following centrifugation, the gastric tissues of each group were studied for the presence of gastric mucosal injuries and morphological changes. The concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) contents were simultaneously investigated. Degree of gastric mucosal injuries were as follows: C group (visually 49.080 ± 10.254, under light microscopy 9.400 ± 2.011) > B group (visually 23.654 ± 9.678, under light microscopy 5.000 ± 1.054) > A group (visually 11.410 ± 3.742, under light microscopy 3.800 ± 1.399). The gastric mucosal MDA content (0.376 ± 0.084 vs 0.235 ± 0.044) was significantly higher in the C group than in the A group, whereas the SOD content (8.852 ± 1.001 vs 10.694 ± 0.965) was lower than that in the A group. However, the MDA and SOD contents did not change much in the B group. Our results suggest that the +Gz exposure might aggravate the acute gastric mucosal injury, and changes in MDA and SOD contents in the gastric tissues indicated that the oxygen free radicals play an important role in this regard.