METTL14/IGF2BP2-mediated m6A modification of STEAP1 aggravates acute lung injury induced by sepsis.

BACKGROUND: Acute lung injury (ALI) is a severe complication of sepsis, characterized by inflammation, edema, and injury to alveolar cells, leading to high mortality rates. Septic ALI is a complex disease involving multiple factors and signaling pathways. STEAP family member 1 (STEAP1) has been reported to be upregulated in a sepsis-induced ALI model. However, the role of STEAP1 in the regulation of septic ALI is not yet fully understood. METHODS: The study stimulated human pulmonary microvascular endothelial cells (HPMECs) using lipopolysaccharides (LPS) to establish an in vitro ALI model. The study used quantitative real-time polymerase chain reaction (qRT-PCR) to measure mRNA expression, and western blotting assay or immunohistochemistry (IHC) assay to analyze protein expression. Cell counting kit-8 (CCK-8) assay was performed to assess cell viability. Flow cytometry was conducted to analyze cell apoptosis. Tube formation assay was used to analyze the tube formation rate of human umbilical vein endothelial cells (HUVECs). Enzyme-linked immunosorbent assays (ELISAs) were used to measure the levels of interleukin-1beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α). The levels of Fe2+ and reactive oxygen species (ROS) were determined using colorimetric and fluorometric assays, respectively. The glutathione (GSH) level was also determined using a colorimetric assay. m6A RNA immunoprecipitation assay, dual-luciferase reporter assay, and RNA immunoprecipitation assay were performed to identify the association of STEAP1 with methyltransferase 14, N6-adenosine-methyltransferase non-catalytic subunit (METTL14) and insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2). The transcript half-life of STEAP1 was analyzed by actinomycin D assay. Finally, a rat model of polymicrobial sepsis was established to analyze the effects of STEAP1 knockdown on lung injury in vivo. RESULTS: We found that the mRNA expression levels of STEAP1 and METTL14 were upregulated in the blood of ALI patients induced by sepsis compared to healthy volunteers. LPS treatment increased the protein levels of STEAP1 and METTL14 in HPMECs. STEAP1 depletion attenuated LPS-induced promoting effects on HPMECs' apoptosis, inflammatory response, and ferroptosis, as well as LPS-induced inhibitory effect on tube formation. We also found that METTL14 and IGF2BP2 stabilized STEAP1 mRNA expression through the m6A methylation modification process. Moreover, METTL14 silencing attenuated LPS-induced effects by decreasing STEAP1 expression in HPMECs, and STEAP1 silencing ameliorated cecal ligation and puncture-induced lung injury of mice. CONCLUSION: METTL14/IGF2BP2-mediated m6A modification of STEAP1 aggravated ALI induced by sepsis. These findings suggest potential therapeutic targets for the treatment of this disease.

INTERFERING HSA_CIRC_0001226 MITIGATES LPS-INDUCED BEAS-2B CELL INJURY BY REGULATING MIR-940/TGFBR2 PATHWAY.

ABSTRACT: Background: Sepsis-associated acute lung injury (SA-ALI) is a serious threat to human health. A growing body of evidence suggested that circular RNAs may be involved in ALI progression. The aim of this study was to investigate the effect and mechanism of circ_0001226 on lipopolysaccharide (LPS)-induced BEAS-2B cells. Methods: BEAS-2B cells were stimulated with LPS to establish a SA-ALI cell model. The expression of circ_0001226, miR-940, and transforming growth factor beta receptor II (TGFBR2) were monitored by quantitative real-time polymerase chain reaction. Cell proliferation and apoptosis were evaluated by the Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine assay, and flow cytometry. The levels of interleukin-6 (IL-6), IL-1ß, and tumor necrosis factor-α were calculated by enzyme-linked immunosorbent assay. Western blot was implemented to test the protein levels of PCNA, Bax, and TGFBR2. Dual-luciferase reporter assay and RNA pull-down assay were adopted to investigate the interaction between circ_0001226 and miR-940, as well as TGFBR2 and miR-940. Results: The levels of circ_0001226 and TGFBR2 were elevated, and miR-940 was decreased in SA-ALI serum specimens and LPS-evoked BEAS-2B cells. Besides that, circ_0001226 interference contributed to cell proliferation and restrained apoptosis and inflammation in LPS-induced BEAS-2B cells. Mechanically, circ_0001226 worked as a molecular sponge of miR-940 to regulate TGFBR2 expression. Conclusion: Circ_0001226 deficiency weakened LPS-mediated proliferation inhibition and inflammatory processes in BEAS-2B cells by binding miR-940 and regulating TGFBR2.

Role and Mechanism of Maresin-1 in Acute Lung Injury Induced by Trauma-Hemorrhagic Shock.

BACKGROUND It is reported that trauma hemorrhagic shock (THS) could resulted in organ injury and is related to a high mortality rate. Maresin-1 (MaR1), a derived medium through biosynthesis, is involved in inflammatory responses. However, the mechanism of MaR1 against acute lung injury needs to be further understood. This report aimed to explore whether MaR1 had a protective effect on lung injury. MATERIAL AND METHODS We constructed a THS-induced acute lung damage rat model and then treated the rats with MaR1. We determined Evan's blue dye (EBD) lung permeability, lung permeability index, wet/dry (W/D) weight ratio, nitric oxide (NO) concentration and inducible nitric oxide synthase (iNOS) expression in lung tissue samples. The inflammation-related cytokines levels in the bronchoalveolar lavage fluid (BALF) and serum of rats were determined by enzyme-linked immunosorbent assay (ELISA). Finally, the TLR4/p38MAPK/NF-kappaB pathway was analyzed by quantitative real-time polymerase chain reaction and western blot assay. RESULTS The increased EBD ratio, lung permeability index and W/D weight ratio, NO concentration and iNOS levels were suppressed by MaR1 treatment. THS-induced over-production of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in BALF and serum was suppressed by MaR1. Besides, the TLR4/p38MAPK/NF-kappaB pathway activation in THS-induced rats were inhibited by MaR1 treatment. CONCLUSIONS Our study showed that MaR1 could effectively alleviated THS-induced lung injury via inhibiting the excitation of the TLR4/p38MAPK/NF-kappaB pathway in THS-induced rats, suggesting that MaR1 might be a novel agent for lung damage treatment.

Study on the Thermal Conductivity Characteristics for Ultra-Thin Body FD SOI MOSFETs Based on Phonon Scattering Mechanisms.

The silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) suffer intensive self-heating effects due to the reduced thermal conductivity of the silicon layer while the feature sizes of devices scale down to the nanometer regime. In this work, analytical models of thermal conductivity considering the self-heating effect (SHE) in ultra-thin body fully depleted (UTB-FD) SOI MOSFETs are presented to investigate the influences of impurity, free and bound electrons, and boundary reflection effects on heat diffusion mechanisms. The thermal conductivities of thin silicon films with different parameters, including temperature, depth, thickness and doping concentration, are discussed in detail. The results show that the thermal dissipation associated with the impurity, the free and bound electrons, and especially the boundary reflection effects varying with position due to phonon scattering, greatly suppressed the heat loss ability of the nanoscale ultra-thin silicon film. The predictive power of the thermal conductivity model is enhanced for devices with sub-10-nm thickness and a heavily doped silicon layer while considering the boundary scattering contribution. The absence of the impurity, the electron or the boundary scattering leads to the unreliability in the model prediction with a small coefficient of determination.