The purpose of our study is to understand the protective role of miR-455-3p against abnormal amyloid precursor protein (APP) processing, amyloid beta (Aβ) formation, defective mitochondrial biogenesis/dynamics and synaptic damage in AD progression. In-silico analysis of miR-455-3p has identified the APP gene as a putative target. Using mutant APP cells, miR-455-3p construct, biochemical and molecular assays, immunofluorescence and transmission electron microscopy (TEM) analyses, we studied the protective effects of miR-455-3p on - 1) APP regulation, amyloid beta (Aβ)(1-40) & (1-42) levels, mitochondrial biogenesis & dynamics; 3) synaptic activities and 4) cell viability & apoptosis. Our luciferase reporter assay confirmed the binding of miR-455-3p at the 3'UTR of APP gene. Immunoblot, sandwich ELISA and immunostaining analyses revealed that the reduced levels of the mutant APP, Aβ(1-40) & Aβ(1-42), and C99 by miR-455-3p. We also found the reduced levels of mRNA and proteins of mitochondrial biogenesis (PGC1α, NRF1, NRF2, and TFAM) and synaptic genes (synaptophysin and PSD95) in mutant APP cells; on the other hand, mutant APP cells that express miR-455-3p showed increased mRNA and protein levels of biogenesis and synaptic genes. Additionally, expression of mitochondrial fission proteins (DRP1 and FIS1) were decreased while the fusion proteins (OPA1, Mfn1 and Mfn2) were increased by miR-455-3p. Our TEM analysis showed a decrease in mitochondria number and an increase in the size of mitochondrial length in mutant APP cells transfected with miR-455-3p. Based on these observations, we cautiously conclude that miR-455-3p regulate APP processing and protective against mutant APP-induced mitochondrial and synaptic abnormalities in AD.
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http://dx.doi.org/10.1016/j.bbadis.2019.06.006 | DOI Listing |
Lipopolysaccharide (LPS) is essential in most Gram-negative bacteria, but mutants of several species have been isolated that can survive in its absence. viability in the absence of LPS is partially dependent on the anionic sphingolipid ceramide diphosphoglycerate (CPG2). Genetic analyses showed that , which encodes a nucleotidyltransferase, is required for CPG2 production.
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IPMC, UMR7275 CNRS-UniCA, INSERM U1323, team certified "Laboratory of Excellence (LABEX) Distalz", Valbonne, France.
Emerging evidence indicates that autophagy is tightly connected to the endocytic pathway. Here, we questioned the role of presenilins (PSENs 1 and 2), previously shown to be involved in autophagy regulation, in the secretion of small endocytic-originating extracellular vesicles known as exosomes. Indeed, while wild-type cells responded to stimuli promoting both multivesicular endosome (MVE) formation and secretion of small extracellular vesicles (sEVs) enriched in canonical exosomal proteins, PSEN-deficient cells were almost unaffected to these stimuli.
View Article and Find Full Text PDFAlzheimers Res Ther
January 2025
Department of Neuroscience "Rita Levi Montalcini", University of Turin, Via Cherasco 15, Turin, 10126, Italy.
Background: Alzheimer's disease (AD) is a progressive neurodegenerative disorder with both genetic and environmental factors contributing to its pathogenesis. While early-onset AD has well-established genetic determinants, the genetic basis for late-onset AD remains less clear. This study investigates a large Italian family with late-onset autosomal dominant AD, identifying a novel rare missense variant in GRIN2C gene associated with the disease, and evaluates the functional impact of this variant.
View Article and Find Full Text PDFJ Clin Invest
January 2025
Growth, Development, and Mental Health of Children and Adolescence Center, Pediatric Research Institute, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, Chongqing Key Laboratory of Child Neurodevelopment and Cognitive Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.
Theranostics
January 2025
Laboratory of Molecular Genetics, College of Pharmacy, Chungbuk National University, Cheongju, 28160, Republic of Korea.
Cathepsin D (Ctsd) has emerged as a promising therapeutic target for Alzheimer's disease (AD) due to its role in degrading intracellular amyloid beta (Aβ). Enhancing Ctsd activity could reduce Aβ42 accumulation and restore the Aβ42/40 ratio, offering a potential AD treatment strategy. This study explored Ctsd demethylation in AD mouse models using dCas9-Tet1-mediated epigenome editing.
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