Metabolic stress induces a double-positive feedback loop between AMPK and SQSTM1/p62 conferring dual activation of AMPK and NFE2L2/NRF2 to synergize antioxidant defense.

Co-occurring mutations in KEAP1 in STK11/LKB1-mutant NSCLC activate NFE2L2/NRF2 to compensate for the loss of STK11-AMPK activity during metabolic adaptation. Characterizing the regulatory crosstalk between the STK11-AMPK and KEAP1-NFE2L2 pathways during metabolic stress is crucial for understanding the implications of co-occurring mutations. Here, we found that metabolic stress increased the expression and phosphorylation of SQSTM1/p62, which is essential for the activation of NFE2L2 and AMPK, synergizing antioxidant defense and tumor growth. The SQSTM1-driven dual activation of NFE2L2 and AMPK was achieved by inducing macroautophagic/autophagic degradation of KEAP1 and facilitating the AXIN-STK11-AMPK complex formation on the lysosomal membrane, respectively. In contrast, the STK11-AMPK activity was also required for metabolic stress-induced expression and phosphorylation of SQSTM1, suggesting a double-positive feedback loop between AMPK and SQSTM1. Mechanistically, SQSTM1 expression was increased by the PPP2/PP2A-dependent dephosphorylation of TFEB and TFE3, which was induced by the lysosomal deacidification caused by low glucose metabolism and AMPK-dependent proton reduction. Furthermore, SQSTM1 phosphorylation was increased by MAP3K7/TAK1, which was activated by ROS and pH-dependent secretion of lysosomal Ca2+. Importantly, phosphorylation of SQSTM1 at S24 and S226 was critical for the activation of AMPK and NFE2L2. Notably, the effects caused by metabolic stress were abrogated by the protons provided by lactic acid. Collectively, our data reveal a novel double-positive feedback loop between AMPK and SQSTM1 leading to the dual activation of AMPK and NFE2L2, potentially explaining why co-occurring mutations in STK11 and KEAP1 happen and providing promising therapeutic strategies for lung cancer.

Extreme UV Resist Exhibiting Synergism between Chemical and Physical Crosslinking Mechanisms.

Carbon-fluorine bonds in fluorinated molecules can undergo homolytic cleavage reactions when electrons are injected, and the resulting radicals combine to form network structures characterized by reduced solubility. This crosslinking chemistry suggests a new category of patterning materials that function under electron beam (e-beam) and extreme ultraviolet (EUV) lithographic conditions. Although this chemistry enables the production of 50 nm or smaller-sized features of simple fluoroalkylated polymers, it is limited by the need for relatively large amounts of irradiation energy to achieve required solubility changes. Therefore, this study was undertaken to devise a sensitivity-enhancing strategy based on a synergistic combination of radical crosslinking and hydrogen-bonding interactions between highly fluoroalkylated copolymers. An alternating copolymer was synthesized using tert-butoxystyrene and a fluoroalkylated maleimide, the former of which produces active hydrogens through catalytic acidolysis reactions. When the polymer was blended with a catalytic amount of a photoacid generator and subjected to lithographic patterning tests under e-beam and EUV irradiation, the deprotection reactions of tert-butoxy moieties proceeded at room temperature and led to a solubility decrease. We presume the small number of hydroxyl moieties produced formed an intermolecular hydrogen-bonding network, which acted synergistically with the covalent crosslinks generated by C-F bonds. When 30 nm features of copolymer thin films were fabricated by EUV lithography, sensitivity was improved by 25-34% without significant deterioration of pattern quality, especially line-edge roughness. These results demonstrate that EUV resists with improved patterning capabilities can be achieved by combining catalytic acidolysis reactions and noncatalytic crosslinking chemistry.

Investigation of correlative parameters to evaluate EUV lithographic performance of PMMA.

Investigations to evaluate the extreme ultraviolet (EUV) lithographic performance of 160 nm thick poly(methyl methacrylate) with 13.5 nm wavelength EUV light were performed using a synchrotron radiation source at Pohang Light Source-II (PLS-II). The single system enabled the determination of the sensitivity, contrast, linear absorption coefficient, critical dimension, and line edge roughness of polymer thin films through tests and measurements. The experimental findings were also compared to theoretical results and those of previously reported studies. According to the results of the dose-to-clear test and transmission measurements, the critical dimension of a line and space pattern (>50 nm) via interference lithography with 250 nm pitch grating agreed well with the results calculated using the lumped parameter model. The experimental results demonstrated that the equipment and test protocol can be used for EUV material infrastructure evaluation in academia and in industry.

Perfluoroalkylated alternating copolymer possessing solubility in fluorous liquids and imaging capabilities under high energy radiation.

A highly fluorinated alternating polymer, P(RFMi-St), possessing improved thermal properties and patterning capabilities over perfluoroalkyl polymethacrylates under high energy radiation was achieved with semi-perfluorododecyl maleimide (RFMi) and styrene (St). RFMi could be synthesised efficiently via a Mitsunobu reaction condition and copolymerised with St by free radical and reversible-deactivation radical polymerisation protocols. P(RFMi-St) showed a satisfactory glass-transition temperature (108 °C) and intermolecular cross-linking behaviour under electron-beam and commercially more important extreme UV (λ = 13.5 nm) irradiation. The exposed regions lost their solubility, resulting in the successful formation of mechanically non-deteriorated negative-tone images down to 50 nm. In addition, P(RFMi-St) could be solution-processed with chemically non-damaging fluorous liquids, which enabled the polymer to be applied effectively on top of an organic semiconductor layer as a dielectric material (dielectric constant 2.7) for the organic field-effect transistor fabrication.

Highly Fluorinated Barium Titanate Nanoparticle Dispersion for Fabrication of Lithographically Patterned Thin Films.

We report the synthesis, characterization, and photopatterning of high-k inorganic nanoparticles that are covered with highly fluorinated carboxylic acid and, as a result, are solution-processable in fluorous liquids. Barium titanate (BTO) nanoparticles, 7-8 nm in diameter, were prepared under solvothermal conditions and were surface-modified with perfluoroalkyl ether-type carboxylic acid molecules via ligand-exchange reactions. Thin films with a high dielectric constant (9.27 at 1 kHz) were achieved by spin-coating homogeneous solutions of BTO nanoparticles in a fluorous solvent (HFE-7500). Additionally, electron-beam lithography and photolithography were applied to the thin films of BTO nanoparticles, yielding BTO patterns with scales of 300 nm and 5 µm, respectively. Thus, an approach for a chemically non-damaging solution process of inorganic materials for device implementation was successfully demonstrated.

Biological activities of a garlic-Cirsium setidens Nakai blend fermented with Leuconostoc mesenteroides.

In this study, we investigated the antioxidant- and immune-stimulating activities of various garlic-Cirsium setidens Nakai blends (fermented and unfermented). The levels of S-allyl cysteine increased by 2.5 times while pectolinarigenin (an anti-inflammatory compound) increased about six times (from 1.1 ± 0.04 mg/g to 6.70 ± 0.12 mg/g) after the garlic-Cirsium setidens Nakai (80:20%, respectively) blend (S4) was fermented with Leuconostoc mesenteroides KCTC 13302. The ferric reducing ability and DPPH radical scavenging activities of all the samples increased significantly after fermentation. Ethanolic extracts of the fermented samples significantly enhanced RAW 264.7 macrophage proliferation in a dose-dependent manner and induced nitric oxide production. Among the samples, S6 and S8 stimulated the highest levels of nitric oxide (NO) production. S6 significantly induced proinflammatory cytokines TNF-α and IL-1ß as well as an anti-inflammatory cytokine IL-10 relative to control. Since the resolution of an infection would require a harmonized interplay of proinflammatory factors and anti-inflammatory cytokines, consumption of S6 could be helpful in promoting health.

Bio-orthogonal fluorinated resist for biomolecules patterning applications.

The patterning of organic materials on solid substrate surfaces has been demonstrated by several methods, such as photolithography, soft lithography, imprint lithography and ink-jet printing. Fluorinated polymers and solvents provide attractive material systems to develop new patterning approaches, as they are chemically orthogonal to non-fluorinated organic molecules, allowing their efficient incorporation in different devices and systems. Moreover, fluorinated polymers are soluble in hydrofluoroether solvents, benign to biomolecules, and can be properly engineered to enable efficient photolithographic patterning. In this work, we report the development of a new photolithographic process for patterning biomolecules on any kind of surfaces either by physical adsorption or covalent bonding. The photoresist is based on a fluorinated material and hydrofluoroether solvents that have minimum interactions with biomolecules and thus they can be characterized as orthogonal to the biomolecules (bio-orthogonal). In both cases, the creation of patterns with dimensions down to 2 µm was achieved. The implementation of the developed photolithographic procedure for the creation of a multi-protein microarray is demonstrated.

Masou salmon (Oncorhynchus masou) ethanol extract decreases 3-hydroxy-3-methylglutaryl coenzyme A reductase expression in diet-induced obese mice.

This study was designed to evaluate the hypocholesterolemic effects of masou salmon 70% ethanol extract (MSE) and to determine the molecular mechanism by which MSE exerts its effects in high-fat (HF) diet-induced obese mice. We hypothesize that the MSE may contain abundant n-3 fatty acids, so a diet containing MSE may also have hypolipidemic effects by assessing several key gene expressions in cholesterol metabolism such as the low-density lipoprotein (LDL) receptor, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, and cholesterol 7alpha-hydroxylase (CYP7A1). To test this hypothesis, C57BL/6J mice were fed a 40% HF diet for 5 weeks, after which time the animals were fed an HF diet containing 0 mg/kg, 75 mg/kg, or 150 mg/kg MSE (HF, HF + MSE 1, and HF + MSE 2 groups, respectively) for an additional 4 weeks (n = 8 in each group, for a total of 24 mice). We found that feeding MSE with an HF diet prevented hypercholesterolemia in diet-induced obese mice; daily MSE feeding reduced total cholesterol levels in plasma and liver by 12.3% and 16.2%, respectively. Furthermore, we examined the expression of key cholesterol metabolism genes by reverse transcription-polymerase chain reaction and found that messenger RNA levels of HMG-CoA reductase were decreased by up to 5-fold, but the expression of both LDL receptor and CYP7A1 did not change. Thus, MSE may exert its hypocholesterolemic effect by altering the expression of HMG-CoA reductase.

Antioxidative and antimutagenic activities of 70% ethanol extract from masou salmon (Oncorhynchus masou).

The masou salmon (Oncorhynchus masou) is a commercially important Pacific salmon species found in Eastern Asian countries such as Korea and Japan. Here, the antioxidative and antimutagenic activities of a 70% ethanol extract from masou salmon (MSE) caught in South Korea was investigated. Folin-Ciocalteu's procedure was used to show the total phenol content of MSE was 3.6+/-0.2 mg/g. Free radical scavenging activity testing using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay system revealed that MSE had considerable antioxidant activity. MSE also had strong reducing power. The Ames Salmonella mutagenicity test employing histidine mutants of the Salmonella typhimurium tester stains TA98 and TA100 was used to examine the mutagenicity of MSE. No mutagenic activity was observed for either test strains at all doses (0.25-25.0 mg/plate). The same test was used to examine the ability of MSE to prevent the acquisition of 4-nitroquinoline-1-oxide (4NQO)- and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced mutations. MSE inhibited mutagenesis in a dose-dependent manner. Our findings provide scientific evidence for the safe use and health benefits of MSE.