scholarly journals Dicer1 promotes Aβ clearance via blocking B2 RNA-mediated repression of apolipoprotein E

2020 ◽  
Author(s):  
Yan Wang ◽  
Meiling Lian ◽  
Liping Song ◽  
Shengzhou Wu
Keyword(s):  
Apolipoprotein E ◽  
Cholesterol Metabolism ◽  
Mrna Degradation ◽  
Amyloid Peptide ◽  
Luciferase Assay ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
B2 Rna ◽  
Β Amyloid ◽  
Alu Rna

AbstractMetabolism of β-amyloid is critical for healthy brain. Decreased clearance of β-amyloid is associated with ensued accumulation of amyloid peptide, culminating in formation of senile plaques, a neuropathological hallmark of Alzheimer’s disease(AD). Apolipoprotein E (APOE), a lipoprotein for phospholipid and cholesterol metabolism, is predominantly synthesized by glia in the central nervous system, controlling Aβ aggregation and metabolism. By use of stereotactic injection and a Morris water maze, we found that delivery of Dicer1-expressing adenovirus into the hippocampus of an animal model of AD mice APPswe/PSEN1deltaE9 significantly improved spatial memory. The effect was associated with reduced amyloid peptides in the hippocampus which were analyzed with immunofluorescence and enzyme-linked immunosorbent assay. With western blot, quantitative real-time PCR, fluorescence in situ hybridization, and northern blot, Dicer1 overexpression increased apolipoprotein E (APOE) and concomitantly decreased B2 RNA in the hippocampus of the AD mice and in astrocyte cultures whereas transfection of B2 Mm2 RNA decreased APOE mRNA and protein levels in astrocyte cultures. Further, human or mouse APOE mRNA was found containing Alu RNA or its equivalent, B2 Mm2 RNA, locating downstream of its 3’-untranslated region (UTR), respectively. The 3’-UTR or 3’-UTR in conjunction with the downstream Alu/B2 RNA were cloned into a luciferase reporter; with dual-luciferase assay, we found that simultaneous transfection of Dicer1 siRNA or Alu/B2 RNA decreased the corresponding luciferase activities which suggest that Alu RNA mediated APOE mRNA degradation. Altogether, Dicer1 expression mediated amyloid peptide clearance by increasing APOE via blocking B2 RNA-mediated APOE mRNA degradation.

scholarly journals Molecular Determinants of the Interaction Between the C-Terminal Domain of Alzheimer's β-Amyloid Peptide and Apolipoprotein E α-Helices

2002 ◽  
Vol 73 (2) ◽  
pp. 758-769 ◽  
Author(s):  
Laurence Lins ◽  
Annick Thomas-Soumarmon ◽  
Thierry Pillot ◽  
Joël Vandekerckhove ◽  
Maryvonne Rosseneu ◽  
...  
Keyword(s):  
Apolipoprotein E ◽  
Amyloid Peptide ◽  
Terminal Domain ◽  
Molecular Determinants ◽  
Β Amyloid ◽  
Β Amyloid Peptide

scholarly journals MiR-27a-3p Targets GLP1R to Regulate Differentiation, Autophagy, and Release of Inflammatory Factors in Pre-Osteoblasts via the AMPK Signaling Pathway

2022 ◽  
Vol 12 ◽  
Author(s):  
Zhi Zeng ◽  
Liangyu Fei ◽  
Juntao Yang ◽  
Jun Zuo ◽  
Zelin Huang ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Target Gene ◽  
Marker Gene ◽  
Luciferase Assay ◽  
Inflammatory Factors ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bone Homeostasis ◽  
Downstream Target ◽  
Downstream Target Gene

Objective: Osteoporosis is caused by the dysregulation of bone homeostasis which is synergistically mediated by osteoclasts and osteoblasts. MiR-27a-3p is a key inhibitor of bone formation. Hence, unearthing the downstream target gene of miR-27a-3p is of great significance to understand the molecular mechanism of osteoporosis.Methods: Bioinformatics analysis was utilized to find the downstream target gene of miR-27a-3p, and dual-luciferase reporter assay was conducted to validate the interplay of miR-27a-3p and GLP1R. Besides, qRT-PCR, Western blot, and enzyme-linked immunosorbent assay (ELISA) were employed to verify the impact of miR-27a-3p on GLP1R expression and the differentiation, autophagy, and inflammatory response of MC3T3-E1 pre-osteoblasts.Results: Dual-luciferase assay validated that miR-27a-3p directly targeted GLP1R. Additionally, posttreatment of MC3T3-E1 cells with miR-27a-3p mimics resulted in a remarkable decrease in expression levels of GLP1R, cell differentiation marker gene, autophagy marker gene, and AMPK. These results indicated that miR-27a-3p targeted GLP1R to inhibit AMPK signal activation and pre-osteoblast differentiation and autophagy, while promoting the release of inflammatory factors.Conclusion: The miR-27a-3p/GLP1R regulatory axis in pre-osteoblasts contributes to understanding the molecular mechanism of osteoporosis.

Isoform-specific vasoconstriction induced by Apolipoprotein E and modulation of this effect by Alzheimer's β-amyloid peptide

1998 ◽  
Vol 256 (2) ◽  
pp. 73-76 ◽  
Author(s):  
Daniel Paris ◽  
Terrence Town ◽  
Timothy A Parker ◽  
James Humphrey ◽  
Michael Mullan
Keyword(s):  
Apolipoprotein E ◽  
Amyloid Peptide ◽  
Β Amyloid ◽  
Β Amyloid Peptide

Alzheimerʼs β-amyloid peptide is conformationally modified by apolipoprotein E in vitro

Neuroreport ◽  
1996 ◽  
Vol 7 (3) ◽  
pp. 721-725 ◽  
Author(s):  
Claudio Soto ◽  
Adam Golabek ◽  
Thomas Wisniewski ◽  
Eduardo M. Castaño
Keyword(s):  
Apolipoprotein E ◽  
Amyloid Peptide ◽  
Β Amyloid ◽  
Β Amyloid Peptide

scholarly journals β-Amyloid Peptide Interacts Specifically with the Carboxyl-Terminal Domain of Human Apolipoprotein E

1999 ◽  
Vol 72 (1) ◽  
pp. 230-237 ◽  
Author(s):  
Thierry Pillot ◽  
Marc Goethals ◽  
Jamilla Najib ◽  
Christine Labeur ◽  
Laurence Lins ◽  
...  
Keyword(s):  
Apolipoprotein E ◽  
Amyloid Peptide ◽  
Human Apolipoprotein ◽  
Terminal Domain ◽  
Carboxyl Terminal Domain ◽  
Β Amyloid ◽  
Carboxyl Terminal ◽  
Β Amyloid Peptide

scholarly journals Apolipoprotein E forms stable complexes with recombinant Alzheimer's disease β-amyloid precursor protein

1997 ◽  
Vol 325 (1) ◽  
pp. 169-175 ◽  
Author(s):  
Cristina HAAS ◽  
Pilar CAZORLA ◽  
Carlos DE MIGUEL ◽  
Fernando VALDIVIESO ◽  
Jesús VÁZQUEZ
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Apolipoprotein E ◽  
Senile Plaques ◽  
Precursor Protein ◽  
Amyloid Peptide ◽  
Reducing Conditions ◽  
Β Amyloid

Apolipoprotein E (apoE), a protein genetically linked to the incidence of Alzheimer's disease, forms SDS-stable complexes in vitro with β-amyloid peptide (Aβ), the primary component of senile plaques. In the present study, we investigated whether apoE was able to bind full-length Aβ precursor protein (APP). Using a maltose-binding-protein–APP fusion protein and human very-low-density lipoprotein (VLDL), we detected an interaction of apoE with APP that was inhibited by Aβ or anti-apoE antibody. Saturation-binding experiments indicated a single binding equilibrium with an apparent 1:1 stoichiometry and a dissociation constant of 15 nM. An interaction was also observed using apoE from cerebrospinal fluid or delipidated VLDL, as well as recombinant apoE. APP·apoE complexes were SDS-stable, and their formation was not inhibited by reducing conditions; however, they were dissociated by SDS under reducing conditions. ApoE·APP complexes formed high-molecular-mass aggregates, and competition experiments suggested that amino acids 14–23 of Aβ are responsible for complex-formation. Finally, no differences were found when studying the interaction of APP with apoE3 or apoE4. Taken together, our results demonstrate that apoE may form stable complexes with the Aβ moiety of APP with characteristics similar to those of complexes formed with isolated Aβ, and suggest the intriguing possibility that apoE–APP interactions may be pathologically relevant in vivo.

scholarly journals Characterizing Apolipoprotein E ε4 Carriers and Noncarriers With the Clinical Diagnosis of Mild to Moderate Alzheimer Dementia and Minimal β-Amyloid Peptide Plaques

2015 ◽  
Vol 72 (10) ◽  
pp. 1124 ◽  
Author(s):  
Sarah E. Monsell ◽  
Walter A. Kukull ◽  
Alex E. Roher ◽  
Chera L. Maarouf ◽  
Geidy Serrano ◽  
...  
Keyword(s):  
Apolipoprotein E ◽  
Clinical Diagnosis ◽  
Amyloid Peptide ◽  
Alzheimer Dementia ◽  
Β Amyloid ◽  
Β Amyloid Peptide

scholarly journals Internalization of β-Amyloid Peptide by Primary Neurons in the Absence of Apolipoprotein E

2007 ◽  
Vol 282 (49) ◽  
pp. 35722-35732 ◽  
Author(s):  
Lucila Saavedra ◽  
Amany Mohamed ◽  
Victoria Ma ◽  
Satyabrata Kar ◽  
Elena Posse de Chaves
Keyword(s):  
Alzheimer Disease ◽  
Apolipoprotein E ◽  
Molecular Mechanisms ◽  
Sympathetic Neurons ◽  
Density Lipoprotein ◽  
Endocytic Pathway ◽  
Amyloid Peptide ◽  
Primary Neurons ◽  
Β Amyloid ◽  
Β Amyloid Peptide

Extracellular accumulation of β-amyloid peptide (Aβ) has been linked to the development of Alzheimer disease. The importance of intraneuronal Aβ has been recognized more recently. Although considerable evidence indicates that extracellular Aβ contributes to the intracellular pool of Aβ, the mechanisms involved in Aβ uptake by neurons are poorly understood. We examined the molecular mechanisms involved in Aβ-(1–42) internalization by primary neurons in the absence of apolipoprotein E. We demonstrated that Aβ-(1–42) is more efficiently internalized by axons than by cell bodies of sympathetic neurons, suggesting that Aβ-(1–42) uptake might be mediated by proteins enriched in the axons. Although the acetylcholine receptor α7nAChR, previously suggested to be involved in Aβ internalization, is enriched in axons, our results indicate that it does not mediate Aβ-(1–42) internalization. Moreover, receptors of the low density lipoprotein receptor family are not essential for Aβ-(1–42) uptake in the absence of apolipoprotein E because receptor-associated protein had no effect on Aβ uptake. By expressing the inactive dynamin mutant dynK44A and the clathrin hub we found that Aβ-(1–42) internalization is independent of clathrin but dependent on dynamin, which suggests an endocytic pathway involving caveolae/lipid rafts. Confocal microscopy studies showing that Aβ did not co-localize with the early endosome marker EEA1 further support a clathrin-independent mechanism. The lack of co-localization of Aβ with caveolin in intracellular vesicles and the normal uptake of Aβ by neurons that do not express caveolin indicate that Aβ does not require caveolin either. Instead partial co-localization of Aβ-(1–42) with cholera toxin subunit B and sensitivity to reduction of cellular cholesterol and sphingolipid levels suggest a caveolae-independent, raft-mediated mechanism. Understanding the molecular events involved in neuronal Aβ internalization might identify potential therapeutic targets for Alzheimer disease.

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