scholarly journals Microtubule affinity–regulating kinase 4 with an Alzheimer's disease-related mutation promotes tau accumulation and exacerbates neurodegeneration

2020 ◽  
Vol 295 (50) ◽  
pp. 17138-17147
Author(s):  
Toshiya Oba ◽  
Taro Saito ◽  
Akiko Asada ◽  
Sawako Shimizu ◽  
Koichi M. Iijima ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
De Novo ◽  
Elevated Risk ◽  
Protein Tau ◽  
Function Mechanism ◽  
Total Tau ◽  
Oligomeric Forms

Accumulation of the microtubule-associated protein tau is associated with Alzheimer's disease (AD). In AD brain, tau is abnormally phosphorylated at many sites, and phosphorylation at Ser-262 and Ser-356 plays critical roles in tau accumulation and toxicity. Microtubule affinity–regulating kinase 4 (MARK4) phosphorylates tau at those sites, and a double de novo mutation in the linker region of MARK4, ΔG316E317D, is associated with an elevated risk of AD. However, it remains unclear how this mutation affects phosphorylation, aggregation, and accumulation of tau and tau-induced neurodegeneration. Here, we report that MARK4ΔG316E317D increases the abundance of highly phosphorylated, insoluble tau species and exacerbates neurodegeneration via Ser-262/356–dependent and –independent mechanisms. Using transgenic Drosophila expressing human MARK4 (MARK4wt) or a mutant version of MARK4 (MARK4ΔG316E317D), we found that coexpression of MARK4wt and MARK4ΔG316E317D increased total tau levels and enhanced tau-induced neurodegeneration and that MARK4ΔG316E317D had more potent effects than MARK4wt. Interestingly, the in vitro kinase activities of MARK4wt and MARK4ΔG316E317D were similar. When tau phosphorylation at Ser-262 and Ser-356 was blocked by alanine substitutions, MARK4wt did not promote tau accumulation or exacerbate neurodegeneration, whereas coexpression of MARK4ΔG316E317D did. Both MARK4wt and MARK4ΔG316E317D increased the levels of oligomeric forms of tau; however, only MARK4ΔG316E317D further increased the detergent insolubility of tau in vivo. Together, these findings suggest that MARK4ΔG316E317D increases tau levels and exacerbates tau toxicity via a novel gain-of-function mechanism and that modification in this region of MARK4 may affect disease pathogenesis.

scholarly journals MARK4 with an Alzheimer’s disease-related mutation promotes tau hyperphosphorylation directly and indirectly and exacerbates neurodegeneration

2020 ◽  
Author(s):  
Toshiya Oba ◽  
Taro Saito ◽  
Akiko Asada ◽  
Sawako Shimizu ◽  
Koichi M. Iijima ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
De Novo ◽  
Elevated Risk ◽  
Protein Tau ◽  
Function Mechanism ◽  
Total Tau ◽  
Oligomeric Forms

AbstractAccumulation of the microtubule-associated protein tau is associated with Alzheimer’s disease (AD). In AD brain, tau is abnormally phosphorylated at many sites, and phosphorylation at Ser262 and Ser356 play critical roles in tau accumulation and toxicity. Microtubule-affinity regulating kinase 4 (MARK4) phosphorylates tau at those sites, and a double de novo mutation in the linker region of MARK4, ΔG316E317InsD, is associated with an elevated risk of AD. However, it remains unclear how this mutation affects phosphorylation, aggregation, and accumulation of tau and tau-induced neurodegeneration. Here, we report that MARK4ΔG316E317D increases the abundance of highly phosphorylated, insoluble tau species and exacerbates neurodegeneration via Ser262/356-dependent and -independent mechanisms. Using transgenic Drosophila expressing human MARK4 (MARK4wt) or a mutant version of MARK4 (MARK4ΔG316E317D), we found that co-expression of MARK4wt and MARK4ΔG316E317D increased total tau levels and enhanced tau-induced neurodegeneration, and that MARK4ΔG316E317D had more potent effects than MARK4wt. Interestingly, the in vitro kinase activities of MARK4wt and MARK4ΔG316E317D were similar. Blocking tau phosphorylation at Ser262 and Ser356 by alanine substitutions protected tau from the effects of MARK4wt, but not from MARK4ΔG316E317D. While both MARK4wt and MARK4ΔG316E317D increased the levels of oligomeric forms of tau, MARK4ΔG316E317D further boosted the levels of tau phosphorylated at several sites other than Ser262/356 and increased the detergent insolubility of tau in vivo. Together, these findings suggest that MARK4ΔG316E317D increases tau levels and exacerbates tau toxicity via an additional gain-of-function mechanism, and that modification in this region of MARK4 may impact disease pathogenesis.

Natural Anti-inflammatory compounds as Drug candidates in Alzheimer’s disease

2020 ◽  
Vol 27 ◽  
Author(s):  
Reyaz Hassan Mir ◽  
Abdul Jalil Shah ◽  
Roohi Mohi-ud-din ◽  
Faheem Hyder Potoo ◽  
Mohd. Akbar Dar ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Natural Products ◽  
Protective Action ◽  
New Drugs ◽  
Huperzine A ◽  
Brain Disorder ◽  
Anti Inflammatory

: Alzheimer's disease (AD) is a chronic neurodegenerative brain disorder characterized by memory impairment, dementia, oxidative stress in elderly people. Currently, only a few drugs are available in the market with various adverse effects. So to develop new drugs with protective action against the disease, research is turning to the identification of plant products as a remedy. Natural compounds with anti-inflammatory activity could be good candidates for developing effective therapeutic strategies. Phytochemicals including Curcumin, Resveratrol, Quercetin, Huperzine-A, Rosmarinic acid, genistein, obovatol, and Oxyresvertarol were reported molecules for the treatment of AD. Several alkaloids such as galantamine, oridonin, glaucocalyxin B, tetrandrine, berberine, anatabine have been shown anti-inflammatory effects in AD models in vitro as well as in-vivo. In conclusion, natural products from plants represent interesting candidates for the treatment of AD. This review highlights the potential of specific compounds from natural products along with their synthetic derivatives to counteract AD in the CNS.

In vivo Evaluation and Alzheimer’s Disease Treatment Outcome of siRNA Loaded Dual Targeting Drug Delivery System

2019 ◽  
Vol 20 (1) ◽  
pp. 56-62 ◽  
Author(s):  
Chi Zhang ◽  
Zhichun Gu ◽  
Long Shen ◽  
Xianyan Liu ◽  
Houwen Lin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Treatment Outcome ◽  
Neuroprotective Effect ◽  
Sirna Delivery ◽  
Repeated Administration ◽  
Spatial Learning And Memory ◽  
In Vivo Evaluation

Background: To deliver drugs to treat Alzheimer’s Disease (AD), nanoparticles should firstly penetrate through blood brain barrier, and then target neurons. Methods: Recently, we developed an Apo A-I and NL4 dual modified nanoparticle (ANNP) to deliver beta-amyloid converting enzyme 1 (BACE1) siRNA. Although promising in vitro results were obtained, the in vivo performance was not clear. Therefore, in this study, we further evaluated the in vivo neuroprotective effect and toxicity of the ANNP/siRNA. The ANNP/siRNA was 80.6 nm with good stability when incubated with serum. In vivo, the treatment with ANNP/siRNA significantly improves the spatial learning and memory of APP/PS1 double transgenic mice, as determined by mean escape latency, times of crossing the platform area during the 60 s swimming and the percentage of the distance in the target quadrant. Results and Conclusion: After the treatment, BACE1 RNA level of ANNP/siRNA group was greatly reduced, which contributed a good AD treatment outcome. Finally, after repeated administration, the ANNP/siRNA did not lead to significant change as observed by HE staining of main organs, suggesting the good biocompatibility of ANNP/siRNA. These results demonstrated that the ANNP was a good candidate for AD targeting siRNA delivery.

Electromagnetic field in Alzheimer’s disease: a literature review of recent preclinical and clinical studies

2020 ◽  
Vol 17 ◽  
Author(s):  
Reem Habib Mohamad Ali Ahmad ◽  
Marc Fakhoury ◽  
Nada Lawand
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
In Vivo Studies ◽  
Key Factors ◽  
Potential Benefits ◽  
Preclinical And Clinical Studies ◽  
The Brain

: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the progressive loss of neurons leading to cognitive and memory decay. The main signs of AD include the irregular extracellular accumulation of amyloidbeta (Aβ) protein in the brain and the hyper-phosphorylation of tau protein inside neurons. Changes in Aβ expression or aggregation are considered key factors in the pathophysiology of sporadic and early-onset AD and correlate with the cognitive decline seen in patients with AD. Despite decades of research, current approaches in the treatment of AD are only symptomatic in nature and are not effective in slowing or reversing the course of the disease. Encouragingly, recent evidence revealed that exposure to electromagnetic fields (EMF) can delay the development of AD and improve memory. This review paper discusses findings from in vitro and in vivo studies that investigate the link between EMF and AD at the cellular and behavioural level, and highlights the potential benefits of EMF as an innovative approach for the treatment of AD.

Targeting PPARalpha in Alzheimer's Disease

2018 ◽  
Vol 15 (4) ◽  
pp. 345-354 ◽  
Author(s):  
Barbara D'Orio ◽  
Anna Fracassi ◽  
Maria Paola Cerù ◽  
Sandra Moreno
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Mechanisms ◽  
Redox Homeostasis ◽  
Antioxidant Response ◽  
Peroxisome Proliferator ◽  
Prevailing Paradigm

Background: The molecular mechanisms underlying Alzheimer's disease (AD) are yet to be fully elucidated. The so-called “amyloid cascade hypothesis” has long been the prevailing paradigm for causation of disease, and is today being revisited in relation to other pathogenic pathways, such as oxidative stress, neuroinflammation and energy dysmetabolism. The peroxisome proliferator-activated receptors (PPARs) are expressed in the central nervous system (CNS) and regulate many physiological processes, such as energy metabolism, neurotransmission, redox homeostasis, autophagy and cell cycle. Among the three isotypes (α, β/δ, γ), PPARγ role is the most extensively studied, while information on α and β/δ are still scanty. However, recent in vitro and in vivo evidence point to PPARα as a promising therapeutic target in AD. Conclusion: This review provides an update on this topic, focussing on the effects of natural or synthetic agonists in modulating pathogenetic mechanisms at AD onset and during its progression. Ligandactivated PPARα inihibits amyloidogenic pathway, Tau hyperphosphorylation and neuroinflammation. Concomitantly, the receptor elicits an enzymatic antioxidant response to oxidative stress, ameliorates glucose and lipid dysmetabolism, and stimulates autophagy.

Targeting Tau Hyperphosphorylation via Kinase Inhibition: Strategy to Address Alzheimer's Disease

2020 ◽  
Vol 20 (12) ◽  
pp. 1059-1073 ◽  
Author(s):  
Ahmad Abu Turab Naqvi ◽  
Gulam Mustafa Hasan ◽  
Md. Imtaiyaz Hassan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Glycogen Synthase ◽  
Paired Helical Filaments ◽  
Tau Hyperphosphorylation ◽  
Microtubule Stabilization ◽  
Extracellular Signal

Microtubule-associated protein tau is involved in the tubulin binding leading to microtubule stabilization in neuronal cells which is essential for stabilization of neuron cytoskeleton. The regulation of tau activity is accommodated by several kinases which phosphorylate tau protein on specific sites. In pathological conditions, abnormal activity of tau kinases such as glycogen synthase kinase-3 β (GSK3β), cyclin-dependent kinase 5 (CDK5), c-Jun N-terminal kinases (JNKs), extracellular signal-regulated kinase 1 and 2 (ERK1/2) and microtubule affinity regulating kinase (MARK) lead to tau hyperphosphorylation. Hyperphosphorylation of tau protein leads to aggregation of tau into paired helical filaments like structures which are major constituents of neurofibrillary tangles, a hallmark of Alzheimer’s disease. In this review, we discuss various tau protein kinases and their association with tau hyperphosphorylation. We also discuss various strategies and the advancements made in the area of Alzheimer's disease drug development by designing effective and specific inhibitors for such kinases using traditional in vitro/in vivo methods and state of the art in silico techniques.

scholarly journals Loss of ferroportin induces memory impairment by promoting ferroptosis in Alzheimer’s disease

2021 ◽  
Author(s):  
Wen-Dai Bao ◽  
Pei Pang ◽  
Xiao-Ting Zhou ◽  
Fan Hu ◽  
Wan Xiong ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Memory Impairment ◽  
Iron Homeostasis ◽  
Critical Role ◽  
Gene Set Enrichment Analysis ◽  
Molecular Characteristics ◽  
Intracellular Iron

AbstractIron homeostasis disturbance has been implicated in Alzheimer’s disease (AD), and excess iron exacerbates oxidative damage and cognitive defects. Ferroptosis is a nonapoptotic form of cell death dependent upon intracellular iron. However, the involvement of ferroptosis in the pathogenesis of AD remains elusive. Here, we report that ferroportin1 (Fpn), the only identified mammalian nonheme iron exporter, was downregulated in the brains of APPswe/PS1dE9 mice as an Alzheimer’s mouse model and Alzheimer’s patients. Genetic deletion of Fpn in principal neurons of the neocortex and hippocampus by breeding Fpnfl/fl mice with NEX-Cre mice led to AD-like hippocampal atrophy and memory deficits. Interestingly, the canonical morphological and molecular characteristics of ferroptosis were observed in both Fpnfl/fl/NEXcre and AD mice. Gene set enrichment analysis (GSEA) of ferroptosis-related RNA-seq data showed that the differentially expressed genes were highly enriched in gene sets associated with AD. Furthermore, administration of specific inhibitors of ferroptosis effectively reduced the neuronal death and memory impairments induced by Aβ aggregation in vitro and in vivo. In addition, restoring Fpn ameliorated ferroptosis and memory impairment in APPswe/PS1dE9 mice. Our study demonstrates the critical role of Fpn and ferroptosis in the progression of AD, thus provides promising therapeutic approaches for this disease.

Genetic Modifiers of Tauopathy in Drosophila

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1233-1242
Author(s):  
Joshua M Shulman ◽  
Mel B Feany
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Mechanisms ◽  
Genetic Modifier ◽  
Genetic Modifiers ◽  
Protein Tau ◽  
Major Class ◽  
Drosophila Model ◽  
Tau Kinases

Abstract In Alzheimer's disease and related disorders, the microtubule-associated protein Tau is abnormally hyperphosphorylated and aggregated into neurofibrillary tangles. Mutations in the tau gene cause familial frontotemporal dementia. To investigate the molecular mechanisms responsible for Tau-induced neurodegeneration, we conducted a genetic modifier screen in a Drosophila model of tauopathy. Kinases and phosphatases comprised the major class of modifiers recovered, and several candidate Tau kinases were similarly shown to enhance Tau toxicity in vivo. Despite some clinical and pathological similarities among neurodegenerative disorders, a direct comparison of modifiers between different Drosophila disease models revealed that the genetic pathways controlling Tau and polyglutamine toxicity are largely distinct. Our results demonstrate that kinases and phosphatases control Tau-induced neurodegeneration and have important implications for the development of therapies in Alzheimer's disease and related disorders.

scholarly journals Marine-Derived Compounds with Anti-Alzheimer’s Disease Activities

Marine Drugs ◽  
2021 ◽  
Vol 19 (8) ◽  
pp. 410
Author(s):  
Salar Hafez Ghoran ◽  
Anake Kijjoa
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Thinking Skills ◽  
Mechanisms Of Action ◽  
Brain Disorder ◽  
Brain Functioning ◽  
Pharmacologically Active ◽  
Pharmacologically Active Compounds

Alzheimer’s disease (AD) is an irreversible and progressive brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to perform simple tasks. As the aging population continues to increase exponentially, AD has become a big concern for society. Therefore, neuroprotective compounds are in the spotlight, as a means to tackle this problem. On the other hand, since it is believed—in many cultures—that marine organisms in an individual diet cannot only improve brain functioning, but also slow down its dysfunction, many researchers have focused on identifying neuroprotective compounds from marine resources. The fact that the marine environment is a rich source of structurally unique and biologically and pharmacologically active compounds, with unprecedented mechanisms of action, marine macroorganisms, such as tunicates, corals, sponges, algae, as well as microorganisms, such as marine-derived bacteria, actinomycetes, and fungi, have been the target sources of these compounds. Therefore, this literature review summarizes and categorizes various classes of marine-derived compounds that are able to inhibit key enzymes involved in AD, including acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), β-secretase (BACE-1), and different kinases, together with the related pathways involved in the pathogenesis of AD. The compounds discussed herein are emerging as promising anti-AD activities for further in-depth in vitro and in vivo investigations, to gain more insight of their mechanisms of action and for the development of potential anti-AD drug leads.

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