BackgroundMETTL3 is an RNA methyltransferase that mediates m6A modification and is implicated in mRNA biogenesis, decay, and translation. However, the biomechanism through which METTL3 regulates MALAT1-miR-1914-3p-YAP axis activity to induce NSCLC drug resistance and metastasis is not very clear.MethodsThe expression of mRNA was analyzed by qPCR assays. Protein levels were analyzed by western blotting and immunofluorescent staining. Cellular proliferation was detected by CCK8 assays. Cell migration and invasion were analyzed by wound healing and transwell assays, respectively. Promoter activities and gene transcription were analyzed by luciferase reporter assays. Finally, m6A modification was analyzed by MeRIP.ResultsMETTL3 increased the m6A modification of YAP. METTL3, YTHDF3, YTHDF1, and eIF3b directly promoted YAP translation through an interaction with the translation initiation machinery. Moreover, the RNA level of MALAT1 was increased due to a higher level of m6A modification mediated by METTL3. Meanwhile, the stability of MALAT1 was increased by METTL3/YTHDF3 complex. Additionally, MALAT1 functions as a competing endogenous RNA that sponges miR-1914-3p to promote the invasion and metastasis of NSCLC via YAP. Furthermore, the reduction of YAP m6A modification by METTL3 knockdown inhibits tumor growth and enhances sensitivity to DDP in vivo.ConclusionResults indicated that the m6A mRNA methylation initiated by METTL3 promotes YAP mRNA translation via recruiting YTHDF1/3 and eIF3b to the translation initiation complex and increases YAP mRNA stability through regulating the MALAT1-miR-1914-3p-YAP axis. The increased YAP expression and activity induce NSCLC drug resistance and metastasis.
Background: The importance of mRNA methylation erased by ALKBH5 in mRNA biogenesis, decay, and translation control is an emerging research focus. Ectopically activated YAP is associated with the development of many human cancers. However, the mechanism whereby ALKBH5 regulates YAP expression and activity to inhibit NSCLC tumor growth and metastasis is not clear. Methods: Protein and transcript interactions were analyzed in normal lung cell and NSCLC cells. Gene expression was evaluated by qPCR and reporter assays. Protein levels were determined by immunochemical approaches. Nucleic acid interactions and status were analyzed by immunoprecipitation. Cell behavior was analyzed by standard biochemical tests. The m 6 A modification was analyzed by MeRIP. Results: Our results show that YAP expression is negatively correlated with ALKBH5 expression and plays an opposite role in the regulation of cellular proliferation, invasion, migration, and EMT of NSCLC cells. ALKBH5 reduced m 6 A modification of YAP. YTHDF3 combined YAP pre-mRNA depending on m 6 A modification. YTHDF1 and YTHDF2 competitively interacted with YTHDF3 in an m 6 A-independent manner to regulate YAP expression. YTHDF2 facilitated YAP mRNA decay via the AGO2 system, whereas YTHDF1 promoted YAP mRNA translation by interacting with eIF3a; both these activities are regulated by m 6 A modification. Furthermore, ALKBH5 decreased YAP activity by regulating miR-107/LATS2 axis in an HuR-dependent manner. Further, ALKBH5 inhibited tumor growth and metastasis in vivo by reducing the expression and activity of YAP. Conclusions: The presented findings suggest m 6 A demethylase ALKBH5 inhibits tumor growth and metastasis by reducing YTHDFs-mediated YAP expression and inhibiting miR-107/LATS2-mediated YAP activity in NSCLC. Moreover, effective inhibition of m 6 A modification of ALKBH5 might constitute a potential treatment strategy for lung cancer.
We report on a novel MoS2/S-doped g-C3N4 heterojunction film with high visible-light photoelectrochemical (PEC) performance. The heterojunction films are prepared by CVD growth of S-doped g-C3N4 film on indium-tin oxide (ITO) glass substrates, with subsequent deposition of a low bandgap, 1.69 eV, visible-light response MoS2 layer by hydrothermal synthesis. Adding thiourea into melamine as the coprecursor not only facilitates the growth of g-C3N4 films but also introduces S dopants into the films, which significantly improves the PEC performance. The fabricated MoS2/S-doped g-C3N4 heterojunction film offers an enhanced anodic photocurrent of as high as ∼1.2 × 10(-4) A/cm(2) at an applied potential of +0.5 V vs Ag/AgCl under the visible light irradiation. The enhanced PEC performance of MoS2/S-doped g-C3N4 film is believed due to the improved light absorption and the efficient charge separation of the photogenerated charge at the MoS2/S-doped g-C3N4 interface. The convenient preparation of carbon nitride based heterojunction films in this work can be widely used to design new heterojunction photoelectrodes or photocatalysts with high performance for H2 evolution.
The influence of environmental attitudes on environmental behaviors has long been discussed. However, few studies have addressed the foundation of such attitudes. In the present study, we explored primitive belief underlying environmental attitudes, i.e., connections with nature, and its relationship with pro-environmental behaviors. Specifically, we used scales, a computerized Implicit Association Test, and a situational simulation experiment to examine both explicit and implicit connections with nature, both deliberate and spontaneous environmental behaviors, and to find correlations between environmental connectedness and environmental behaviors. Results showed that explicit connectedness was positively correlated with deliberate environmental behaviors, while implicit connectedness was positively correlated with spontaneous environmental behaviors. Additionally, explicit and implicit connectedness was independent of each other. In conclusion, the current study confirms the positive role played by connections with nature in promoting environmental behavior, and accordingly suggests means to encourage pro-environmental behavior by enhancing people’s connectedness to nature.
Lipid oxidation is commonly seen in the innate immune response, in which reactive oxygen intermediates are generated to kill pathogenic microorganisms. Although oxidation products of phospholipids have generally been regarded to play a role in a number of chronic inflammatory processes, several studies have shown that oxidized phospholipids inhibit the LPS-induced acute proinflammatory response in cultured macrophages and endothelial cells. We report in this study that oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC), but not nonoxidized PAPC, significantly inhibits the LPS-induced TNF-alpha response in intact mice. Oxidized PAPC also inhibits the 2'-deoxyribo(cytidine-phosphate-guanosine) (CpG) DNA-induced TNF-alpha response in cultured macrophages and intact mice. To elucidate the mechanisms of action, we show that oxidized PAPC, but not nonoxidized PAPC, inhibits the LPS- and CpG-induced activation of p38 MAPK and the NF-kappaB cascade. These results suggest a role for oxidized lipids as a negative regulator in controlling the magnitude of the innate immune response. Further studies on the mechanisms of action may lead to development of a new type of anti-inflammatory drug for treatment of acute inflammatory diseases such as sepsis.
The oxylipin pathway is of central importance for plant defensive responses. Yet, the first step of the pathway, the liberation of linolenic acid following induction, is poorly understood. Phospholipases D (PLDs) have been hypothesized to mediate this process, but data from Arabidopsis (Arabidopsis thaliana) regarding the role of PLDs in plant resistance have remained controversial. Here, we cloned two chloroplast-localized PLD genes from rice (Oryza sativa), OsPLDa4 and OsPLDa5, both of which were up-regulated in response to feeding by the rice striped stem borer (SSB) Chilo suppressalis, mechanical wounding, and treatment with jasmonic acid (JA). Antisense expression of OsPLDa4 and -a5 (as-pld), which resulted in a 50% reduction of the expression of the two genes, reduced elicited levels of linolenic acid, JA, green leaf volatiles, and ethylene and attenuated the SSB-induced expression of a mitogen-activated protein kinase (OsMPK3), a lipoxygenase (OsHI-LOX), a hydroperoxide lyase (OsHPL3), as well as a 1-aminocyclopropane-1-carboxylic acid synthase (OsACS2). The impaired oxylipin and ethylene signaling in as-pld plants decreased the levels of herbivore-induced trypsin protease inhibitors and volatiles, improved the performance of SSB and the rice brown planthopper Nilaparvata lugens, and reduced the attractiveness of plants to a larval parasitoid of SSB, Apanteles chilonis. The production of trypsin protease inhibitors in as-pld plants could be partially restored by JA, while the resistance to rice brown planthopper and SSB was restored by green leaf volatile application. Our results show that phospholipases function as important components of herbivore-induced direct and indirect defenses in rice.
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