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[Display omitted] • As an important mineral nutrient, Mg2+ inhibits the activity of COX-2 via mTORC1. • By nutrient deprivation, COX-2 activation induces formation of LC3B autophagosomes. • Mg2+ disrupts the formation of LC3B autophagosomes via deactivating the COX-2. • COX-2 disturbs hydrolysis of Aβ via suppressing activity of UCH-L1 in lysosomes. • Tyr 385 is critical for the activity of COX-2 in cognitive decline of AD. Nutrient deficiency has been recently suggested to be associated with the deposition of β-amyloid protein (Aβ) during the course of Alzheimer's disease (AD) development and progression. We thereby aimed to reveal the roles of a deficiency in important mineral nutrient, magnesium ions (Mg2+), in the deposition of Aβ via autophagy mechanisms. Specifically, we report here that Mg2+ functions as a critical enhancer of the formation of the mammalian target of rapamycin complex 1 (mTORC1) by inhibiting the expression and enzymatic activity of cyclooxygenase-2 (COX-2), which is responsible for inducing autophagosome formation, as indicated by the microtubule-associated protein 1 light chain 3 beta (LC3B) puncta. Although autophagosome generation was strongly induced in COX-2 Tg mice, COX-2 overexpression facilitated Aβ deposition by disrupting the proteolytic function of autolysosomes through an ubiquitin carboxy terminal hydrolase L1 (UCH-L1)-depressing mechanism. More interestingly, COX-2 mutation at Tyr 385 restores the activity of UCH-L1, which results in Aβ degradation and improvements in the cognitive decline of APP/PS1 Tg mice. [ABSTRACT FROM AUTHOR]

Highlights • The unusual ClAlPc molecular self-assembled layer on a buffer layer have large deformations compared with the common ClAlPc bilayer. • Almost freestanding environment is provided for the molecules when the influence from the substrate is shielded by the buffer layer. • The dominated intermolecular interaction is likely to be the dispersion forces via Reduced Density Gradient analysis. Abstract We report an unusual self-assembled layer structure of chloroaluminium phthalocyanine (ClAlPc) molecules on highly ordered pyrolytic graphite (HOPG), in which a close-packed well-ordered monolayer is separated from the substrate by a relatively disordered buffer layer, as revealed using scanning tunneling microscopy (STM). Our close-packed monolayer has a nearly rectangular lattice, instead of the distinctly different square lattice for the more commonly observed well-ordered bilayer structure. This may be due to the dominance of intermolecular interactions within the monolayer when the influence from the substrate is shielded by the buffer layer. Density Functional Theory (DFT) calculations and Reduced Density Gradient (RDG) analysis indicate that the dominant intermolecular interaction within the unusual layer is likely the London dispersion force. Graphic abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract: Using angle-resolved photoemission spectroscopy (ARPES), we investigate the electronic structure of Cu-doped topological insulator Bi2Te3 on Si(111) substrate prepared by molecular beam epitaxy (MBE) to clarify the doping nature of Cu atoms in the films. By systematic studying the structural and electronic properties of the Cu-doped Bi2Te3 films by different doping methods, we find that Cu acts as electron donors when deposited onto the surface of Bi2Te3 films while behave as holes when doped in the process of Bi2Te3 thin film growth. The model of the formation of Cu+, five/seven layer lamella structures and Cu2−x Te is proposed to explain the different doping mechanisms. The robustness of topological surface states and insensitivity to non-magnetic impurities is indicated. [Copyright &y& Elsevier]