scholarly journals Steroids and Alzheimer’s Disease: Changes Associated with Pathology and Therapeutic Potential

2020 ◽  
Vol 21 (13) ◽  
pp. 4812 ◽  
Author(s):  
Yvette Akwa
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Therapeutic Potential ◽  
Current Knowledge ◽  
Memory Loss ◽  
Amyloid Β ◽  
Neuroactive Steroids ◽  
Age Related ◽  
Pathogenic Factors ◽  
The Relationship

Alzheimer’s disease (AD) is a multifactorial age-related neurodegenerative disease that today has no effective treatment to prevent or slow its progression. Neuroactive steroids, including neurosteroids and sex steroids, have attracted attention as potential suitable candidates to alleviate AD pathology. Accumulating evidence shows that they exhibit pleiotropic neuroprotective properties that are relevant for AD. This review focuses on the relationship between selected neuroactive steroids and the main aspects of AD disease, pointing out contributions and gaps with reference to sex differences. We take into account the regulation of brain steroid concentrations associated with human AD pathology. Consideration is given to preclinical studies in AD models providing current knowledge on the neuroprotection offered by neuroactive (neuro)steroids on major AD pathogenic factors, such as amyloid-β (Aβ) and tau pathology, mitochondrial impairment, neuroinflammation, neurogenesis and memory loss. Stimulating endogenous steroid production opens a new steroid-based strategy to potentially overcome AD pathology. This article is part of a Special Issue entitled Steroids and the Nervous System.

scholarly journals Alzheimer’s disease: many failed trials, so where do we go from here?

2020 ◽  
Vol 68 (6) ◽  
pp. 1135-1140 ◽  
Author(s):  
Allison Bethanne Reiss ◽  
Amy D Glass ◽  
Thomas Wisniewski ◽  
Benjamin Wolozin ◽  
Irving H Gomolin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Current Knowledge ◽  
Memory Loss ◽  
Treatment Strategies ◽  
Amyloid Β ◽  
Tau Proteins ◽  
Brain Disorder ◽  
The Central Nervous System ◽  
Progressive Cognitive Impairment

Alzheimer’s disease (AD) is a neurodegenerative brain disorder associated with relentlessly progressive cognitive impairment and memory loss. AD pathology proceeds for decades before cognitive deficits become clinically apparent, opening a window for preventative therapy. Imbalance of clearance and buildup of amyloid β and phosphorylated tau proteins in the central nervous system is believed to contribute to AD pathogenesis. However, multiple clinical trials of treatments aimed at averting accumulation of these proteins have yielded little success, and there is still no disease-modifying intervention. Here, we discuss current knowledge of AD pathology and treatment with an emphasis on emerging biomarkers and treatment strategies.

Probiotic Releasing Angiotensin (1-7) in a Drosophila Model of Alzheimer’s Disease Produces Sex-Specific Effects on Cognitive Function

2021 ◽  
pp. 1-13
Author(s):  
C. Aaron Smith ◽  
Haddon Smith ◽  
Lisa Roberts ◽  
Lori Coward ◽  
Gregory Gorman ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Therapeutic Potential ◽  
Memory Loss ◽  
Amyloid Β ◽  
Kynurenine Pathway ◽  
Lactobacillus Paracasei ◽  
Amyloid Β Protein ◽  
Complex Disorders ◽  
Model Of Alzheimer’S Disease

Background: While extensive research on the brain has failed to identify effective therapies, using probiotics to target the gut microbiome has shown therapeutic potential in Alzheimer’s disease (AD). Genetically modified probiotics (GMP) are a promising strategy to deliver key therapeutic peptides with high efficacy and tissue specificity. Angiotensin (Ang)-(1-7) levels inversely correlate to AD severity, but its administration is challenging. Our group has successfully established a GMP-based method of Ang-(1-7) delivery. Objective: Since Drosophila represents an excellent model to study the effect of probiotics on complex disorders in a high throughput manner, we tested whether oral supplementation with Lactobacillus paracasei releasing Ang-(1-7) (LP-A) delays memory loss in a Drosophila AD model. Methods: Flies overexpressing the human amyloid-β protein precursor and its β-site cleaving enzyme in neurons were randomized to receive four 24-h doses of Lactobacillus paracasei alone (LP), LP-A or sucrose over 14 days. Memory was assessed via an aversive phototaxic suppression assay. Results: Optimal dilution,1:2, was determined based on palatability. LP-A improved memory in trained AD males but worsened cognition in AD females. LP-supplementation experiments confirmed that Ang-(1-7) conferred additional cognitive benefits in males and was responsible for the deleterious cognitive effects in females. Sex-specific differences in the levels of angiotensin peptides and differential activation of the kynurenine pathway of tryptophan metabolism in response to supplementation may underlie this male-only therapeutic response. Conclusion: In summary, LP-A ameliorated the memory deficits of a Drosophila AD model, but effects were sex-specific. Dosage optimization may be required to address this differential response.

scholarly journals Amelioration of Alzheimer’s disease pathology by mitophagy inducers identified via machine learning and a cross-species workflow

2022 ◽  
Author(s):  
Chenglong Xie ◽  
Xu-Xu Zhuang ◽  
Zhangming Niu ◽  
Ruixue Ai ◽  
Sofie Lautrup ◽  
...  
Keyword(s):  
Machine Learning ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Memory Loss ◽  
Amyloid Β ◽  
Cholinergic Neurons ◽  
Molecular Structures ◽  
Age Related ◽  
Combined Use ◽  
Vector Representations

AbstractA reduced removal of dysfunctional mitochondria is common to aging and age-related neurodegenerative pathologies such as Alzheimer’s disease (AD). Strategies for treating such impaired mitophagy would benefit from the identification of mitophagy modulators. Here we report the combined use of unsupervised machine learning (involving vector representations of molecular structures, pharmacophore fingerprinting and conformer fingerprinting) and a cross-species approach for the screening and experimental validation of new mitophagy-inducing compounds. From a library of naturally occurring compounds, the workflow allowed us to identify 18 small molecules, and among them two potent mitophagy inducers (Kaempferol and Rhapontigenin). In nematode and rodent models of AD, we show that both mitophagy inducers increased the survival and functionality of glutamatergic and cholinergic neurons, abrogated amyloid-β and tau pathologies, and improved the animals’ memory. Our findings suggest the existence of a conserved mechanism of memory loss across the AD models, this mechanism being mediated by defective mitophagy. The computational–experimental screening and validation workflow might help uncover potent mitophagy modulators that stimulate neuronal health and brain homeostasis.

scholarly journals Neuroprotective Effects of Quercetin in Alzheimer’s Disease

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 59 ◽  
Author(s):  
Haroon Khan ◽  
Hammad Ullah ◽  
Michael Aschner ◽  
Wai San Cheang ◽  
Esra Küpeli Akkol
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Fruits And Vegetables ◽  
Recent Literature ◽  
Therapeutic Potential ◽  
Antioxidant Properties ◽  
Amyloid Β ◽  
Neuroprotective Effects ◽  
The Relationship

Quercetin is a flavonoid with notable pharmacological effects and promising therapeutic potential. It is widely distributed among plants and found commonly in daily diets predominantly in fruits and vegetables. Neuroprotection by quercetin has been reported in several in vitro studies. It has been shown to protect neurons from oxidative damage while reducing lipid peroxidation. In addition to its antioxidant properties, it inhibits the fibril formation of amyloid-β proteins, counteracting cell lyses and inflammatory cascade pathways. In this review, we provide a synopsis of the recent literature exploring the relationship between quercetin and cognitive performance in Alzheimer’s disease and its potential as a lead compound in clinical applications.

The Therapeutic Potential of Purinergic Receptors in Alzheimer’s Disease and Promising Therapeutic Modulators

2020 ◽  
Vol 20 ◽  
Author(s):  
Lili Pan ◽  
Yu Ma ◽  
Yunchun Li ◽  
Haoxing Wu ◽  
Rui Huang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Purinergic Receptors ◽  
Therapeutic Potential ◽  
Purinergic Signaling ◽  
Memory Loss ◽  
Related Research ◽  
Central Nervous System Disorders ◽  
G Protein Coupled

Abstract:: Recent studies have proven that the purinergic signaling pathway plays a key role in neurotransmission and neuromodulation, and is involved in various neurodegenerative diseases and psychiatric disorders. With the characterization of the subtypes of receptors in purinergic signaling, i.e. the P1 (adenosine), P2X (ion channel) and P2Y (G protein-coupled), more attentions were paid to the pathophysiology and therapeutic potential of purinergic signaling in central nervous system disorders. Alzheimer’s disease (AD) is a progressive and deadly neurodegenerative disease that is characterized by memory loss, cognitive impairment and dementia. However, as drug development aimed to prevent or control AD follows a series of failures in recent years, more researchers focused on the neuroprotection-related mechanisms such as purinergic signaling in AD patients to find a potential cure. This article reviews the recent discoveries of purinergic signaling in AD, summaries the potential agents as modulators for the receptors of purinergic signaling in AD related research and treatments. Thus, our paper provided an insight for purinergic signaling in the development of anti-AD therapies.

Microglia in Alzheimer’s Disease

2020 ◽  
Vol 17 (1) ◽  
pp. 29-43 ◽  
Author(s):  
Patrick Süß ◽  
Johannes C.M. Schlachetzki
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Current Knowledge ◽  
Imaging Techniques ◽  
Amyloid Β ◽  
Disease Stage ◽  
Disease Modifying Therapy ◽  
Transcriptomic Signature

: Alzheimer’s Disease (AD) is the most frequent neurodegenerative disorder. Although proteinaceous aggregates of extracellular Amyloid-β (Aβ) and intracellular hyperphosphorylated microtubule- associated tau have long been identified as characteristic neuropathological hallmarks of AD, a disease- modifying therapy against these targets has not been successful. An emerging concept is that microglia, the innate immune cells of the brain, are major players in AD pathogenesis. Microglia are longlived tissue-resident professional phagocytes that survey and rapidly respond to changes in their microenvironment. Subpopulations of microglia cluster around Aβ plaques and adopt a transcriptomic signature specifically linked to neurodegeneration. A plethora of molecules and pathways associated with microglia function and dysfunction has been identified as important players in mediating neurodegeneration. However, whether microglia exert either beneficial or detrimental effects in AD pathology may depend on the disease stage. : In this review, we summarize the current knowledge about the stage-dependent role of microglia in AD, including recent insights from genetic and gene expression profiling studies as well as novel imaging techniques focusing on microglia in human AD pathology and AD mouse models.

scholarly journals A novel orally active HDAC6 inhibitor T-518 shows a therapeutic potential for Alzheimer’s disease and tauopathy in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Onishi ◽  
Ryouta Maeda ◽  
Michiko Terada ◽  
Sho Sato ◽  
Takahiro Fujii ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Therapeutic Potential ◽  
Drug Candidate ◽  
Histone Deacetylase 6 ◽  
Cellular Assays ◽  
Age Related ◽  
Acetylation State ◽  
Hdac6 Inhibitor ◽  
Orally Active

AbstractAccumulation of tau protein is a key pathology of age-related neurodegenerative diseases such as Alzheimer's disease and progressive supranuclear palsy. Those diseases are collectively termed tauopathies. Tau pathology is associated with axonal degeneration because tau binds to microtubules (MTs), a component of axon and regulates their stability. The acetylation state of MTs contributes to stability and histone deacetylase 6 (HDAC6) is a major regulator of MT acetylation status, suggesting that pharmacological HDAC6 inhibition could improve axonal function and may slow the progression of tauopathy. Here we characterize N-[(1R,2R)-2-{3-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-5-oxo-5H,6H,7H-pyrrolo[3,4-b]pyridin-6-yl}cyclohexyl]-2,2,3,3,3-pentafluoropropanamide (T-518), a novel, potent, highly selective HDAC6 inhibitor with clinically favorable pharmacodynamics. T-518 shows potent inhibitory activity against HDAC6 and superior selectivity over other HDACs compared with the known HDAC6 inhibitors in the enzyme and cellular assays. T-518 showed brain penetration in an oral dose and blocked HDAC6-dependent tubulin deacetylation at Lys40 in mouse hippocampus. A 2-week treatment restored impaired axonal transport and novel object recognition in the P301S tau Tg mouse, tauopathy model, while a 3-month treatment also decreased RIPA-insoluble tau accumulation. Pharmaceutical inhibition of HDAC6 is a potential therapeutic strategy for tauopathy, and T-518 is a particularly promising drug candidate.

scholarly journals Induced Pluripotent Stem Cell-Derived Neural Precursors Improve Memory, Synaptic and Pathological Abnormalities in a Mouse Model of Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1802
Author(s):  
Enrique Armijo ◽  
George Edwards ◽  
Andrea Flores ◽  
Jorge Vera ◽  
Mohammad Shahnawaz ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Clinical Symptoms ◽  
Memory Loss ◽  
Amyloid Β ◽  
Cerebral Atrophy ◽  
Brain Inflammation ◽  
Neural Precursors ◽  
Model Of Alzheimer’S Disease ◽  
Induced Pluripotent

Alzheimer’s disease (AD) is the most common type of dementia in the elderly population. The disease is characterized by progressive memory loss, cerebral atrophy, extensive neuronal loss, synaptic alterations, brain inflammation, extracellular accumulation of amyloid-β (Aβ) plaques, and intracellular accumulation of hyper-phosphorylated tau (p-tau) protein. Many recent clinical trials have failed to show therapeutic benefit, likely because at the time in which patients exhibit clinical symptoms the brain is irreversibly damaged. In recent years, induced pluripotent stem cells (iPSCs) have been suggested as a promising cell therapy to recover brain functionality in neurodegenerative diseases such as AD. To evaluate the potential benefits of iPSCs on AD progression, we stereotaxically injected mouse iPSC-derived neural precursors (iPSC-NPCs) into the hippocampus of aged triple transgenic (3xTg-AD) mice harboring extensive pathological abnormalities typical of AD. Interestingly, iPSC-NPCs transplanted mice showed improved memory, synaptic plasticity, and reduced AD brain pathology, including a reduction of amyloid and tangles deposits. Our findings suggest that iPSC-NPCs might be a useful therapy that could produce benefit at the advanced clinical and pathological stages of AD.

Main Plant Extracts’ Active Properties Effective on Scopolamine-Induced Memory Loss

2017 ◽  
Vol 32 (7) ◽  
pp. 418-428 ◽  
Author(s):  
Ioana-Miruna Balmus ◽  
Alin Ciobica
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Plant Extracts ◽  
Current Knowledge ◽  
Symptomatic Relief ◽  
Memory Loss ◽  
Current Treatment ◽  
General Effect ◽  
Function Loss ◽  
Theory Research

Alzheimer’s disease leads to progressive cognitive function loss, which may impair both intellectual capacities and psychosocial aspects. Although the current knowledge points to a multifactorial character of Alzheimer’s disease, the most issued pathological hypothesis remains the cholinergic theory. The main animal model used in cholinergic theory research is the scopolamine-induced memory loss model. Although, in some cases, a temporary symptomatic relief can be obtained through targeting the cholinergic or glutamatergic neurotransmitter systems, no current treatment is able to stop or slow cognitive impairment. Many potentially successful therapies are often blocked by the blood–brain barrier since it exhibits permeability only for several classes of active molecules. However, the plant extracts’ active molecules are extremely diverse and heterogeneous regarding the biochemical structure. In this way, many active compounds constituting the recently tested plant extracts may exhibit the same general effect on acetylcholine pathway, but on different molecular ground, which can be successfully used in Alzheimer’s disease adjuvant therapy.

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

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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