A Peptide-Based Nanocarrier for an Enhanced Delivery and Targeting of Flurbiprofen into the Brain for the Treatment of Alzheimer’s Disease: An In Vitro Study

Alzheimer’s disease (AD) is an age-related disease caused by abnormal accumulation of amyloid-β in the brain leading to progressive tissue degeneration. Flurbiprofen (FP), a drug used to mitigate the disease progression, has low efficacy due to its limited permeability across the blood–brain barrier (BBB). In a previous work, FP was coupled at the uppermost branching of an ε-lysine-based branched carrier, its root presenting a phenylalanine moiety able to increase the hydrophobicity of the complex and enhance the transport across the BBB by adsorptive-mediated transcytosis (AMT). The present study explores a different molecular design of the FP-peptide delivery system, whereby its root presents an ApoE-mimicking peptide, a targeting ligand that could enhance transport across the BBB by receptor-mediated transcytosis (RMT). The functionalised complex was synthesised using a solid-phase peptide synthesis and characterised by mass spectrometry and FTIR. Cytotoxicity and permeability of this complex across an in vitro BBB model were analysed. Moreover, its activity and degradation to release the drug were investigated. The results revealed successful synthesis and grafting of FP molecules at the uppermost molecular branches of the lysine terminal without observed cytotoxicity. When covalently linked to the nanocarrier, FP was still active on target cells, albeit with a reduced activity, and was released as a free drug upon hydrolysis in a lysosome-mimicking medium. Noticeably, this work shows the high efficiency of RMT-driven FP delivery over delivery systems relying on AMT.

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β-hydroxybutyrate Impedes the Progression of Alzheimer’s Disease and Atherosclerosis in ApoE-Deficient Mice

Nutrients ◽

10.3390/nu12020471 ◽

2020 ◽

Vol 12 (2) ◽

pp. 471 ◽

Cited By ~ 3

Author(s):

Manigandan Krishnan ◽

Jong Su Hwang ◽

Mikyung Kim ◽

Yun Jin Kim ◽

Ji Hae Seo ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Therapeutic Potential ◽

Density Lipoprotein ◽

In Vitro Study ◽

Substantia Nigra Pars Compacta ◽

Apo E ◽

The Brain ◽

Deficient Mice

β-hydroxybutyrate (β-OHB) has been shown to exert an anti-inflammatory activity. Apolipoprotein-E (ApoE) is strongly associated with atherosclerosis and Alzheimer’s disease (AD). This study aimed to explore the therapeutic effect of β-OHB in the brain and the aorta of high-fat diet (HFD)-fed ApoE-deficient mice. We found in Apo-E deficient mice that β-OHB attenuated lipid deposition in the choroid plexus (ChP) and decreased amyloid plaque in the substantia nigra pars compacta. We also found decreased CD68-positive macroglia infiltration of the ChP in β-OHB-treated ApoE-deficient mice. β-OHB treatment ameliorated IgG extravasation into the hippocampal region of the brain. In vitro study using ChP mice cell line revealed that β-OHB attenuated oxidized low-density lipoprotein-induced ApoE-specific differentially expressed inflammatory ChP genes. Treatment with β-OHB reduced aortic plaque formation without affecting blood lipid profiles and decreased serum production of resistin, a well-established risk factor for both AD and atherosclerosis. Thus, the current study suggests and describes the therapeutic potential of β-OHB for the treatment of AD and atherosclerosis.

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A Systematic Review of Glucose Transport Alterations in Alzheimer's Disease

Frontiers in Neuroscience ◽

10.3389/fnins.2021.626636 ◽

2021 ◽

Vol 15 ◽

Author(s):

Natalia Kyrtata ◽

Hedley C. A. Emsley ◽

Oli Sparasci ◽

Laura M. Parkes ◽

Ben R. Dickie

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Glucose Transport ◽

Clinical Symptoms ◽

Amyloid Β ◽

Neuronal Cell ◽

Glucose Transporters ◽

Rodent Models ◽

The Brain

Introduction: Alzheimer's disease (AD) is characterized by cerebral glucose hypometabolism. Hypometabolism may be partly due to reduced glucose transport at the blood-brain barrier (BBB) and across astrocytic and neuronal cell membranes. Glucose transporters (GLUTs) are integral membrane proteins responsible for moving glucose from the bloodstream to parenchymal cells where it is metabolized, and evidence indicates vascular and non-vascular GLUTs are altered in AD brains, a process which could starve the brain of glucose and accelerate cognitive decline. Here we review the literature on glucose transport alterations in AD from human and rodent studies.Methods: Literature published between 1st January 1946 and 1st November 2020 within EMBASE and MEDLINE databases was searched for the terms “glucose transporters” AND “Alzheimer's disease”. Human and rodent studies were included while reviews, letters, and in-vitro studies were excluded.Results: Forty-three studies fitting the inclusion criteria were identified, covering human (23 studies) and rodent (20 studies). Post-mortem studies showed consistent reductions in GLUT1 and GLUT3 in the hippocampus and cortex of AD brains, areas of the brain closely associated with AD pathology. Tracer studies in rodent models of AD and human AD also exhibit reduced uptake of glucose and glucose-analogs into the brain, supporting these findings. Longitudinal rodent studies clearly indicate that changes in GLUT1 and GLUT3 only occur after amyloid-β pathology is present, and several studies indicate amyloid-β itself may be responsible for GLUT changes. Furthermore, evidence from human and rodent studies suggest GLUT depletion has severe effects on brain function. A small number of studies show GLUT2 and GLUT12 are increased in AD. Anti-diabetic medications improved glucose transport capacity in AD subjects.Conclusions: GLUT1 and GLUT3 are reduced in hippocampal and cortical regions in patients and rodent models of AD, and may be caused by high levels of amyloid-β in these regions. GLUT3 reductions appear to precede the onset of clinical symptoms. GLUT2 and GLUT12 appear to increase and may have a compensatory role. Repurposing anti-diabetic drugs to modify glucose transport shows promising results in human studies of AD.

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CERTL Reduces C16 Ceramide, Amyloid-β Levels and Inflammation in a Model of Alzheimer's Disease

10.21203/rs.3.rs-42740/v1 ◽

2020 ◽

Author(s):

Simone Mwenda Crivelli ◽

Qian Luo ◽

Jo Stevens ◽

Caterina Giovagnoni ◽

Daan van Kruining ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neuroblastoma Cells ◽

Amyloid Β ◽

Amyloid Plaque ◽

Model Of Alzheimer’S Disease ◽

Aβ Aggregation ◽

The Brain

Abstract Background: Deregulation of ceramide and sphingomyelin levels have been suggested to contribute to the pathogenesis of Alzheimer’s disease (AD). Ceramide transfer proteins (CERTs) are ceramide carriers, crucial for ceramide and sphingomyelin balance in cells. Extracellular forms of CERTs co-localize with amyloid-β (Aβ) plaques in AD brains. To date, the significance of these observations for the pathophysiology of AD remains uncertain.Methods: The plasmid expressing CERTL, the long isoform of CERTs, was used to study the interaction of CERTL with amyloid precursor protein (APP) by co-immunoprecipitation and immunofluorescence in HEK cells. The recombinant CERTL protein was employed to study interaction of CERTL with amyloid-β (Aβ), Aβ aggregation process in presence of CERTL, and the resulting changes in Aβ toxicity in neuroblastoma cells. CERTL was overexpressed in neurons by adeno associated virus (AAV) in a familial mouse model of familial AD (5xFAD). Ten weeks after transduction animal were challenged with behavior tests for memory, anxiety and locomotion. At week twelve brains were investigated for sphingolipid levels by mass spectrometry, plaques and neuroinflammation by immunohistochemistry, gene expression and/or immunoassay.Results: Here, we report that CERTL, binds to APP, modifies Aβ aggregation and reduces Aβ neurotoxicity in vitro. Furthermore, we show that intracortical injection of AAV, mediating the expression of CERTL, decreases levels of ceramide d18:1/16:0 and increases sphingomyelin levels in the brain of male transgenic mice, modelling familial AD (5xFAD). CERTL in vivo over-expression has a mild effect on animal locomotion and decreases Aβ formation and modulates microglia by decreasing their pro-inflammatory phenotype.Conclusion: Our results demonstrate a crucial role of CERTL in regulating ceramide levels in the brain, in amyloid plaque formation and neuroinflammation, thereby opening research avenues for therapeutic targets of AD and other neurodegenerative diseases.

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A Study of the SORL1 Gene in the Pathogenesis of Late-onset Alzheimer’s Disease by Affecting the Expression of BDNF

10.21203/rs.3.rs-750372/v1 ◽

2021 ◽

Author(s):

Mingri Zhao ◽

Jiangfeng Liu ◽

Jingli He ◽

Xun Chen ◽

Yanjin Feng ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Late Onset ◽

Cell Model ◽

Amyloid Β ◽

Cognitive Disorders ◽

Amyloid Β Protein ◽

Bdnf Expression ◽

The Brain

Abstract BackgroundAlzheimer’s disease is a neurodegenerative disease characterized by progressive memory impairment and other cognitive disorders. It is divided into Familial Alzheimer's disease (FAD) and Sporadic Alzheimer's disease (SAD). SAD is also called delayed Late-onset Alzheimer's disease (LOAD). Sortilin Related Receptor 1 (SORL1) is a high-risk pathogenic gene of LOAD, which can participate in the occurrence and development of AD by affecting the transport and metabolism of intracellular β-amyloid precursor protein (APP). The expression of SORL1 is significantly downregulated in patients with LOAD.ResultsIn the SORL1 knockout (SORL1 KO) mouse model constructed by CRISPR/cas9, we found that the expression of Brain Derived Neurotrophic Factor (BDNF) in the brain of SORL1 KO mice was significantly down-regulated and Amyloid β-protein (Aβ) deposition was found in the brain ofSORL1 KO mice. Through the SORL1 knockdown N2a cell model constructed by shRNA, we also found that when the SORL1 expression was knocked down, the BDNF expression was also downregulated and the cell viability decreased. The results of immunohistochemistry and in vitro cell model experiments suggest that the downregulation of BDNF caused by SORL1 knockdown may be mainly achieved by affecting the expression and distribution of N-Methyl-D-aspartate (NMDAR).ConclusionsSORL1 knockout changes the expression and distribution of NMDAR in cells, downregulates the expression of BDNF, and thus affects the learning and memory of mice.

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In vitro study of interaction of 17β-hydroxysteroid dehydrogenase type 10 and cyclophilin D and its potential implications for Alzheimer’s disease

Scientific Reports ◽

10.1038/s41598-019-53157-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Erika Hemmerová ◽

Tomáš Špringer ◽

Zdenka Krištofiková ◽

Jiří Homola

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mitochondrial Permeability Transition ◽

Amyloid Β ◽

In Vitro Study ◽

Permeability Transition ◽

Stable Complex ◽

Cyclophilin D ◽

Permeability Transition Pores

Abstract In early stages of Alzheimer’s disease (AD), amyloid-β (Aβ) accumulates in neuronal mitochondria where it interacts with a number of biomolecules including 17beta-hydroxysteroide dehydrogenase 10 (17β-HSD10) and cyclophilin D (cypD). It has been hypothesized that 17β-HSD10 interacts with cypD preventing it from opening mitochondrial permeability transition pores and that its regulation during AD may be affected by the accumulation of Aβ. In this work, we demonstrate for the first time that 17β-HSD10 and cypD form a stable complex in vitro. Furthermore, we show that factors, such as pH, ionic environment and the presence of Aβ, affect the ability of 17β-HSD10 to bind cypD. We demonstrate that K+ and Mg2+ ions present at low levels may facilitate this binding. We also show that different fragments of Aβ (Aβ1–40 and Aβ1–42) affect the interaction between 17β-HSD10 and cypD differently and that Aβ1–42 (in contrast to Aβ1–40) is capable of simultaneously binding both 17β-HSD10 and cypD in a tri-complex.

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Modulation of β-Amyloid Fibril Formation in Alzheimer’s Disease by Microglia and Infection

Frontiers in Molecular Neuroscience ◽

10.3389/fnmol.2020.609073 ◽

2020 ◽

Vol 13 ◽

Author(s):

Madeleine R. Brown ◽

Sheena E. Radford ◽

Eric W. Hewitt

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Fibril ◽

Amyloid Β ◽

Aβ Peptides ◽

Aβ Amyloid ◽

Aβ Fibrils ◽

The Brain

Amyloid plaques are a pathological hallmark of Alzheimer’s disease. The major component of these plaques are highly ordered amyloid fibrils formed by amyloid-β (Aβ) peptides. However, whilst Aβ amyloid fibril assembly has been subjected to detailed and extensive analysis in vitro, these studies may not reproduce how Aβ fibrils assemble in the brain. This is because the brain represents a highly complex and dynamic environment, and in Alzheimer’s disease multiple cofactors may affect the assembly of Aβ fibrils. Moreover, in vivo amyloid plaque formation will reflect the balance between the assembly of Aβ fibrils and their degradation. This review explores the roles of microglia as cofactors in Aβ aggregation and in the clearance of amyloid deposits. In addition, we discuss how infection may be an additional cofactor in Aβ fibril assembly by virtue of the antimicrobial properties of Aβ peptides. Crucially, by understanding the roles of microglia and infection in Aβ amyloid fibril assembly it may be possible to identify new therapeutic targets for Alzheimer’s disease.

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CERTL reduces C16 ceramide, amyloid-β levels, and inflammation in a model of Alzheimer’s disease

Alzheimer s Research & Therapy ◽

10.1186/s13195-021-00780-0 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Simone M. Crivelli ◽

Qian Luo ◽

Jo A.A. Stevens ◽

Caterina Giovagnoni ◽

Daan van Kruining ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neuroblastoma Cells ◽

Amyloid Β ◽

Amyloid Plaque ◽

Model Of Alzheimer’S Disease ◽

Aβ Aggregation ◽

The Brain

Abstract Background Dysregulation of ceramide and sphingomyelin levels have been suggested to contribute to the pathogenesis of Alzheimer’s disease (AD). Ceramide transfer proteins (CERTs) are ceramide carriers which are crucial for ceramide and sphingomyelin balance in cells. Extracellular forms of CERTs co-localize with amyloid-β (Aβ) plaques in AD brains. To date, the significance of these observations for the pathophysiology of AD remains uncertain. Methods A plasmid expressing CERTL, the long isoform of CERTs, was used to study the interaction of CERTL with amyloid precursor protein (APP) by co-immunoprecipitation and immunofluorescence in HEK cells. The recombinant CERTL protein was employed to study interaction of CERTL with amyloid-β (Aβ), Aβ aggregation process in presence of CERTL, and the resulting changes in Aβ toxicity in neuroblastoma cells. CERTL was overexpressed in neurons by adeno-associated virus (AAV) in a mouse model of familial AD (5xFAD). Ten weeks after transduction, animals were challenged with behavior tests for memory, anxiety, and locomotion. At week 12, brains were investigated for sphingolipid levels by mass spectrometry, plaques, and neuroinflammation by immunohistochemistry, gene expression, and/or immunoassay. Results Here, we report that CERTL binds to APP, modifies Aβ aggregation, and reduces Aβ neurotoxicity in vitro. Furthermore, we show that intracortical injection of AAV, mediating the expression of CERTL, decreases levels of ceramide d18:1/16:0 and increases sphingomyelin levels in the brain of male 5xFAD mice. CERTL in vivo over-expression has a mild effect on animal locomotion, decreases Aβ formation, and modulates microglia by decreasing their pro-inflammatory phenotype. Conclusion Our results demonstrate a crucial role of CERTL in regulating ceramide levels in the brain, in amyloid plaque formation and neuroinflammation, thereby opening research avenues for therapeutic targets of AD and other neurodegenerative diseases.

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The Combination of β-Asarone and Icariin Inhibits Amyloid-β and Reverses Cognitive Deficits by Promoting Mitophagy in Models of Alzheimer’s Disease

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/7158444 ◽

2021 ◽

Vol 2021 ◽

pp. 1-20

Author(s):

Nanbu Wang ◽

Haoyu Wang ◽

Qi Pan ◽

Jian Kang ◽

Ziwen Liang ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Combination Therapy ◽

Cognitive Deficits ◽

Amyloid Β ◽

In Vivo Models ◽

Age Related ◽

The Individual

β-Asarone is the main constituent of Acorus tatarinowii Schott and exhibits important effects in diseases such as neurodegenerative and neurovascular diseases. Icariin (ICA) is a major active ingredient of Epimedium that has attracted increasing attention because of its unique pharmacological effects in degenerative disease. In this paper, we primarily explored the effects of the combination of β-asarone and ICA in clearing noxious proteins and reversing cognitive deficits. The accumulation of damaged mitochondria and mitophagy are hallmarks of aging and age-related neurodegeneration, including Alzheimer’s disease (AD). Here, we provide evidence that autophagy/mitophagy is impaired in the hippocampus of APP/PS1 mice and in Aβ1-42-induced PC12 cell models. Enhanced mitophagic activity has been reported to promote Aβ and tau clearance in in vitro and in vivo models. Meanwhile, there is growing evidence that treatment of AD should be preceded by intervention before the formation of pathological products. The efficacy of the combination therapy was better than that of the individual therapies applied separately. Then, we found that the combination therapy also inhibited cell and mitochondrial damage by inducing autophagy/mitophagy. These findings suggest that impaired removal of defective mitochondria is a pivotal event in AD pathogenesis, and that combination treatment with mitophagy inducers represents a potential strategy for therapeutic intervention.

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CERTL reduces C16 ceramide, amyloid-β levels and inflammation in a model of Alzheimer's disease

10.21203/rs.3.rs-42740/v3 ◽

2021 ◽

Author(s):

Simone Mwenda Crivelli ◽

Qian Luo ◽

Jo A.A. Stevens ◽

Caterina Giovagnoni ◽

Daan van Kruining ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neuroblastoma Cells ◽

Amyloid Β ◽

Amyloid Plaque ◽

Model Of Alzheimer’S Disease ◽

Aβ Aggregation ◽

The Brain

Abstract Background: Dysregulation of ceramide and sphingomyelin levels have been suggested to contribute to the pathogenesis of Alzheimer’s disease (AD). Ceramide transfer proteins (CERTs) are ceramide carriers which are crucial for ceramide and sphingomyelin balance in cells. Extracellular forms of CERTs co-localize with amyloid-β (Aβ) plaques in AD brains. To date, the significance of these observations for the pathophysiology of AD remains uncertain.Methods: A plasmid expressing CERTL, the long isoform of CERTs, was used to study the interaction of CERTL with amyloid precursor protein (APP) by co-immunoprecipitation and immunofluorescence in HEK cells. The recombinant CERTL protein was employed to study interaction of CERTL with amyloid-β (Aβ), Aβ aggregation process in presence of CERTL, and the resulting changes in Aβ toxicity in neuroblastoma cells. CERTL was overexpressed in neurons by adeno associated virus (AAV) in a mouse model of familial AD (5xFAD). Ten weeks after transduction, animals were challenged with behavior tests for memory, anxiety and locomotion. At week twelve, brains were investigated for sphingolipid levels by mass spectrometry, plaques and neuroinflammation by immunohistochemistry, gene expression and/or immunoassay.Results: Here, we report that CERTL, binds to APP, modifies Aβ aggregation and reduces Aβ neurotoxicity in vitro. Furthermore, we show that intracortical injection of AAV, mediating the expression of CERTL, decreases levels of ceramide d18:1/16:0 and increases sphingomyelin levels in the brain of male 5xFAD mice. CERTL in vivo over-expression has a mild effect on animal locomotion, decreases Aβ formation and modulates microglia by decreasing their pro-inflammatory phenotype.Conclusion: Our results demonstrate a crucial role of CERTL in regulating ceramide levels in the brain, in amyloid plaque formation and neuroinflammation, thereby opening research avenues for therapeutic targets of AD and other neurodegenerative diseases.

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Bacterial Extracellular DNA Promotes β-Amyloid Aggregation

Microorganisms ◽

10.3390/microorganisms9061301 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1301

Author(s):

George Tetz ◽

Victor Tetz

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Protein Misfolding ◽

Amyloid Β ◽

Extracellular Dna ◽

Bacterial Dna ◽

Aβ Aggregation ◽

The Brain

Alzheimer’s disease is associated with prion-like aggregation of the amyloid β (Aβ) peptide and the subsequent accumulation of misfolded neurotoxic aggregates in the brain. Therefore, it is critical to clearly identify the factors that trigger the cascade of Aβ misfolding and aggregation. Numerous studies have pointed out the association between microorganisms and their virulence factors and Alzheimer’s disease; however, their exact mechanisms of action remain unclear. Recently, we discovered a new pathogenic role of bacterial extracellular DNA, triggering the formation of misfolded Tau aggregates. In this study, we investigated the possible role of DNA extracted from different bacterial and eukaryotic cells in triggering Aβ aggregation in vitro. Interestingly, we found that the extracellular DNA of some, but not all, bacteria is an effective trigger of Aβ aggregation. Furthermore, the acceleration of Aβ nucleation and elongation can vary based on the concentration of the bacterial DNA and the bacterial strain from which this DNA had originated. Our findings suggest that bacterial extracellular DNA might play a previously overlooked role in the Aβ protein misfolding associated with Alzheimer’s disease pathogenesis. Moreover, it highlights a new mechanism of how distantly localized bacteria can remotely contribute to protein misfolding and diseases associated with this process. These findings might lead to the use of bacterial DNA as a novel therapeutic target for the prevention and treatment of Alzheimer’s disease.

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