ABSTRACT
Microglia play a pivotal role in clearance of Aβ by degrading them in lysosomes, countering amyloid plaque pathogenesis in Alzheimer's disease (AD). Recent evidence suggests that lysosomal dysfunction leads to insufficient elimination of toxic protein aggregates. We tested whether enhancing lysosomal function with transcription factor EB (TFEB), an essential regulator modulating lysosomal pathways, would promote Aβ clearance in microglia. Here we show that microglial expression of TFEB facilitates fibrillar Aβ (fAβ) degradation and reduces deposited amyloid plaques, which are further enhanced by deacetylation of TFEB. Using mass spectrometry analysis, we firstly confirmed acetylation as a previously unreported modification of TFEB and found that SIRT1 directly interacted with and deacetylated TFEB at lysine residue 116. Subsequently, SIRT1 overexpression enhanced lysosomal function and fAβ degradation by upregulating transcriptional levels of TFEB downstream targets, which could be inhibited when TFEB was knocked down. Furthermore, overexpression of deacetylated TFEB at K116R mutant in microglia accelerated intracellular fAβ degradation by stimulating lysosomal biogenesis and greatly reduced the deposited amyloid plaques in the brain slices of APP/PS1 transgenic mice. Our findings reveal that deacetylation of TFEB could regulate lysosomal biogenesis and fAβ degradation, making microglial activation of TFEB a possible strategy for attenuating amyloid plaque deposition in AD.
Subject(s)
Animals , Humans , Mice , Alzheimer Disease , Metabolism , Pathology , Amyloid beta-Peptides , Metabolism , Amyloid beta-Protein Precursor , Genetics , Metabolism , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors , Chemistry , Genetics , Metabolism , Brain , Metabolism , Cells, Cultured , Chloride Channels , Genetics , Metabolism , Disease Models, Animal , HEK293 Cells , Lysosomes , Genetics , Metabolism , Mice, Transgenic , Microglia , Cell Biology , Metabolism , Mutagenesis, Site-Directed , Peptides , Chemistry , Protein Binding , RNA Interference , Sirtuin 1 , Genetics , MetabolismABSTRACT
A series of [1,3]dioxolo[4,5-f]isoindolone derivatives were designed, synthesized and evaluated as inhibitors of acetylcholinesterases (AChE). Furthermore, their effects on memory impairment of mice induced by scopolamine were investigated with step-through test. The results suggested that most of the target compounds exhibited potential inhibition on AChE with IC50 values at micromolar range. Compounds I1 (IC50 value of 0.086 μmol · L(-1)) and I2 (IC50 value of 0.080 μmol · L(-1)) showed the strongest AChE inhibitory activity, which are equipotent to donepezil (IC50 value of 0.094 μmol · L(-1)). Moreover, compounds I1-I4 could improve the memory impairment induced by scopolamine in mice.
ABSTRACT
A series of novel 4-substituted-3-nitrobenzamide derivatives were designed and synthesized. The structures of the target compounds were confirmed with 1H NMR, 13C NMR, MS and element analysis. Anti-tumor activities against HCT-116, MDA-MB435 and HL-60 cell lines in vitro were evaluated by SRB assay. The results indicated most of the target compounds exhibited potent anti-tumor activity. Compound 4a showed the most potent inhibitory activities against three cancer cell lines with the GI50 values of 1.904-2.111 micromol x L(-1). Compounds 4g, 41-4n exhibited more potent inhibitory activities against MDA-MB435 and HL-60 cell lines with the GI50 values of 1.008-3.586 micromol x L(-1) and 1.993-3.778 micromol x L(-1), respectively. The structure-activity relationship of these compounds is discussed preliminarily.