lncRNA SNHG1 Knockdown Alleviates Amyloid-β-Induced Neuronal Injury by Regulating ZNF217 via Sponging miR-361-3p in Alzheimer’s Disease

Background: Long noncoding RNAs have been proven to play an important role in the progression of Alzheimer’s disease (AD). However, the function of small nucleolar RNA host gene 1 (SNHG1) in AD progression remains to be studied. Objective: To explore the role of SNHG1 in AD progression and clarify its potential mechanism. Methods: Amyloid β-protein (Aβ) was used to construct an AD cell model in vitro. The expression levels of SNHG1 and miR-361-3p were determined by quantitative real-time polymerase chain reaction. Cell viability and apoptosis were measured by cell counting kit 8 assay and flow cytometry. The levels of apoptosis-related proteins and zinc finger gene 217 (ZNF217) protein were evaluated by western blot analysis. Additionally, the contents of inflammatory cytokines and oxidative stress markers were tested by enzyme-linked immunosorbent assay. Furthermore, dual-luciferase reporter and RNA immunoprecipitation assays were used to verify the interaction between miR-361-3p and SNHG1 or ZNF217. Results: Aβ could induce cell injury, while resveratrol could reverse this effect. SNHG1 expression was positively regulated by Aβ and negatively regulated by resveratrol. SNHG1 knockdown could reverse the promotion effect of Aβ on cell injury. Moreover, SNHG1 sponged miR-361-3p, and miR-361-3p targeted ZNF217. Additionally, miR-361-3p overexpression reversed the promotion effect of SNHG1 overexpression on cell injury, and ZNF217 silencing also reversed the promotion effect of miR-361-3p inhibitor on cell injury. Conclusion: SNHG1 promoted cell injury by regulating the miR-361-3p/ZNF217 axis, which might provide a theoretical basis for molecular therapy of AD.

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Toxic Amyloid-β42 Conformer May Accelerate the Onset of Alzheimer’s Disease in the Preclinical Stage

Journal of Alzheimer s Disease ◽

10.3233/jad-201407 ◽

2021 ◽

pp. 1-8

Author(s):

Akinori Futamura ◽

Sotaro Hieda ◽

Yukiko Mori ◽

Kensaku Kasuga ◽

Azusa Sugimoto ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Β ◽

Japanese Version ◽

Enzyme Linked Immunosorbent Assay ◽

Amyloid Β Protein ◽

Clinical Dementia Rating ◽

Preclinical Ad ◽

Β Protein ◽

Mci Due To Ad

Background: Toxic amyloid-β protein (Aβ) conformers play an important role in the progression of Alzheimer’s disease (AD). The ratio of toxic conformer to total Aβ42 in cerebrospinal fluid (CSF) was significantly high in AD and mild cognitive impairment (MCI) due to AD using an enzyme-linked immunosorbent assay kit with a 24B3 antibody. Objective: We compared the toxic Aβ42, conformer at different stages of AD to identify its contribution to AD pathogenesis. Methods: We compared 5 patients with preclinical AD, 11 patients with MCI due to AD, 21 patients with AD, and 5 healthy controls to measure CSF levels of total Aβ42, total tau, tau phosphorylated at threonine 181 (p-tau), and toxic Aβ conformers. All were classified using the Clinical Dementia Rating. Cognitive function was assessed using the Japanese version of the Mini-Mental State Examination (MMSE-J). Results: Toxic Aβ conformer level was insignificant between groups, but its ratio to Aβ42 was significantly higher in AD than in preclinical AD (p < 0.05). Toxic Aβ42 conformer correlated positively with p-tau (r = 0.67, p < 0.01) and p-tau correlated negatively with MMSE-J (r = –0.38, p < 0.05). Conclusion: Toxic Aβ conformer triggers tau accumulation leading to neuronal impairment in AD pathogenesis.

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A Super-Resolved View of the Alzheimer’s Disease-Related Amyloidogenic Pathway in Hippocampal Neurons

Journal of Alzheimer s Disease ◽

10.3233/jad-215008 ◽

2021 ◽

pp. 1-20

Author(s):

Yang Yu ◽

Yang Gao ◽

Bengt Winblad ◽

Lars Tjernberg ◽

Sophia Schedin Weiss

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Hippocampal Neurons ◽

Three Dimensional ◽

Amyloid Β ◽

Stimulated Emission ◽

Amyloid Β Peptide ◽

Primary Neurons ◽

Amyloid Β Protein ◽

Early Endosomes

Background: Processing of the amyloid-β protein precursor (AβPP) is neurophysiologically important due to the resulting fragments that regulate synapse biology, as well as potentially harmful due to generation of the 42 amino acid long amyloid β-peptide (Aβ 42), which is a key player in Alzheimer’s disease. Objective: Our aim was to clarify the subcellular locations of the amyloidogenic AβPP processing in primary neurons, including the intracellular pools of the immediate substrate, AβPP C-terminal fragment (APP-CTF) and the product (Aβ 42). To overcome the difficulties of resolving these compartments due to their small size, we used super-resolution microscopy. Methods: Mouse primary hippocampal neurons were immunolabelled and imaged by stimulated emission depletion (STED) microscopy, including three-dimensional, three-channel imaging and image analyses. Results: The first (β-secretase) and second (γ-secretase) cleavages of AβPP were localized to functionally and distally distinct compartments. The β-secretase cleavage was observed in early endosomes, where we were able to show that the liberated N- and C-terminal fragments were sorted into distinct vesicles budding from the early endosomes in soma. Lack of colocalization of Aβ 42 and APP-CTF in soma suggested that γ-secretase cleavage occurs in neurites. Indeed, APP-CTF was, in line with Aβ 42 in our previous study, enriched in the presynapse but absent from the postsynapse. In contrast, full-length AβPP was not detected in either the pre- or the postsynaptic side of the synapse. Furthermore, we observed that endogenously produced and endocytosed Aβ 42 were localized in different compartments. Conclusion: These findings provide critical super-resolved insight into amyloidogenic AβPP processing in primary neurons.

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Circ-ACTR2 aggravates the high glucose-induced cell dysfunction of human renal mesangial cells through mediating the miR-205-5p/HMGA2 axis in diabetic nephropathy

Diabetology & Metabolic Syndrome ◽

10.1186/s13098-021-00692-x ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Jie Yun ◽

Jinyu Ren ◽

Yufei Liu ◽

Lijuan Dai ◽

Liqun Song ◽

...

Keyword(s):

Oxidative Stress ◽

Diabetic Nephropathy ◽

High Glucose ◽

Cell Injury ◽

Mesangial Cells ◽

Protein Detection ◽

Cell Counting ◽

Luciferase Reporter ◽

Enzyme Linked Immunosorbent Assay ◽

Cell Dysfunction

Abstract Background Circular RNAs (circRNAs) have been considered as pivotal biomarkers in Diabetic nephropathy (DN). CircRNA ARP2 actin-related protein 2 homolog (circ-ACTR2) could promote the HG-induced cell injury in DN. However, how circ-ACTR2 acts in DN is still unclear. This study aimed to explore the molecular mechanism of circ-ACTR2 in DN progression, intending to provide support for the diagnostic and therapeutic potentials of circ-ACTR2 in DN. Methods RNA expression analysis was conducted by the quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell growth was measured via Cell Counting Kit-8 and EdU assays. Inflammatory response was assessed by Enzyme-linked immunosorbent assay. The protein detection was performed via western blot. Oxidative stress was evaluated by the commercial kits. The molecular interaction was affirmed through dual-luciferase reporter and RNA immunoprecipitation assays. Results Circ-ACTR2 level was upregulated in DN samples and high glucose (HG)-treated human renal mesangial cells (HRMCs). Silencing the circ-ACTR2 expression partly abolished the HG-induced cell proliferation, inflammation and extracellular matrix accumulation and oxidative stress in HRMCs. Circ-ACTR2 was confirmed as a sponge for miR-205-5p. Circ-ACTR2 regulated the effects of HG on HRMCs by targeting miR-205-5p. MiR-205-5p directly targeted high-mobility group AT-hook 2 (HMGA2), and HMGA2 downregulation also protected against cell injury in HG-treated HRMCs. HG-mediated cell dysfunction was repressed by miR-205-5p/HMGA2 axis. Moreover, circ-ACTR2 increased the expression of HMGA2 through the sponge effect on miR-205-5p in HG-treated HRMCs. Conclusion All data have manifested that circ-ACTR2 contributed to the HG-induced DN progression in HRMCs by the mediation of miR-205-5p/HMGA2 axis.

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Selective Secretase Targeting for Alzheimer’s Disease Therapy

Journal of Alzheimer s Disease ◽

10.3233/jad-201027 ◽

2021 ◽

pp. 1-17

Author(s):

Alvaro Miranda ◽

Enrique Montiel ◽

Henning Ulrich ◽

Cristian Paz

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Β ◽

Amyloid Plaques ◽

Neuroprotective Activity ◽

Amyloid Β Protein ◽

Secretase Activity ◽

Membrane Bound ◽

Aβ Production ◽

Bace 1

Alzheimer’s disease (AD) is associated with marked atrophy of the cerebral cortex and accumulation of amyloid plaques and neurofibrillary tangles. Amyloid plaques are formed by oligomers of amyloid-β (Aβ) in the brain, with a length of 42 and 40 amino acids. α-secretase cleaves amyloid-β protein precursor (AβPP) producing the membrane-bound fragment CTFα and the soluble fragment sAβPPα with neuroprotective activity; β-secretase produces membrane-bound fragment CTFβ and a soluble fragment sAβPPβ. After α-secretase cleavage of AβPP, γ-secretase cleaves CTFα to produce the cytoplasmic fragment AICD and P3 in the non-amyloidogenic pathway. CTFβ is cleaved by γ-secretase producing AICD as well as Aβ in amyloidogenic pathways. In the last years, the study of natural products and synthetic compounds, such as α-secretase activity enhancers, β-secretase inhibitors (BACE-1), and γ-secretase activity modulators, have been the focus of pharmaceuticals and researchers. Drugs were improved regarding solubility, blood-brain barrier penetration, selectivity, and potency decreasing Aβ42. In this regard, BACE-1 inhibitors, such as Atabecestat, NB-360, Umibecestat, PF-06751979, Verubecestat, LY2886721, Lanabecestat, LY2811376, and Elenbecestat, were submitted to phase I-III clinical trials. However, inhibition of Aβ production did not recover cognitive functions or reverse the disease. Novel strategies are being developed, aiming at a partial reduction of Aβ production, such as the development of γ-secretase modulators or α-secretase enhancers. Such therapeutic tools shall focus on slowing down or minimizing the progression of neuronal damage. Here, we summarize structures and the activities of the latest compounds designed for AD treatment, with remarkable in vitro, in vivo, and clinical phase activities.

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GM1 Ganglioside-Bound Amyloid β-Protein in Alzheimer’s Disease Brain

Neurobiology of Aging ◽

10.1016/s0197-4580(98)00032-3 ◽

1998 ◽

Vol 19 (1) ◽

pp. S65-S67 ◽

Cited By ~ 59

Author(s):

K Yanagisawa ◽

Y Ihara

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Β ◽

Amyloid Β Protein ◽

Gm1 Ganglioside ◽

Β Protein

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Case of early-onset Alzheimer’s disease with atypical manifestation

General Psychiatry ◽

10.1136/gpsych-2020-100283 ◽

2021 ◽

Vol 34 (1) ◽

pp. e100283

Author(s):

Lin Zhu ◽

Limin Sun ◽

Lin Sun ◽

Shifu Xiao

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Clinical Manifestation ◽

Early Onset ◽

Short Term Memory ◽

Brain Mri ◽

Memory Loss ◽

Amyloid Β ◽

Amyloid Β Protein ◽

Fluent Aphasia

Short-term memory decline is the typical clinical manifestation of Alzheimer’s disease (AD). However, early-onset AD usually has atypical symptoms and may get misdiagnosed. In the present case study, we reported a patient who experienced symptoms of memory loss with progressive non-fluent aphasia accompanied by gradual social withdrawal. He did not meet the diagnostic criteria of AD based on the clinical manifestation and brain MRI. However, his cerebrospinal fluid examination showed a decreased level of beta-amyloid 42, and increased total tau and phosphorylated tau. Massive amyloid β-protein deposition by 11C-Pittsburgh positron emission tomography confirmed the diagnosis of frontal variant AD. This case indicated that early-onset AD may have progressive non-fluent aphasia as the core manifestation. The combination of individual and precision diagnosis would be beneficial for similar cases.

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