Journal of Alzheimer's Disease - Volume Pre-press, issue Pre-press

Authors: Huang, Wenhao | Xia, Qing | Zheng, Feifei | Zhao, Xue | Ge, Fangliang | Xiao, Jiaying | Liu, Zijie | Shen, Yingying | Ye, Ke | Wang, Dayong | Li, Yanze

Article Type: Review Article

Abstract: The neurovascular unit (NVU) is involved in the pathological changes in Alzheimer’s disease (AD). The NVU is a structural and functional complex that maintains microenvironmental homeostasis and metabolic balance in the central nervous system. As one of the most important components of the NVU, microglia not only induce blood-brain barrier breakdown by promoting neuroinflammation, the infiltration of peripheral white blood cells and oxidative stress but also mediate neurovascular uncoupling by inducing mitochondrial dysfunction in neurons, abnormal contraction of cerebral vessels, and pericyte loss in AD. In addition, microglia-mediated dysfunction of cellular components in the NVU, such as astrocytes and pericytes, …can destroy the integrity of the NVU and lead to NVU impairment. Therefore, we review the mechanisms of microglia-mediated NVU dysfunction in AD. Furthermore, existing therapeutic advancements aimed at restoring the function of microglia and the NVU in AD are discussed. Finally, we predict the role of pericytes in microglia-mediated NVU dysfunction in AD is the hotspot in the future. Show more

Keywords: Alzheimer’s disease, blood-brain barrier, microglia, neurovascular uncoupling, neurovascular unit, pericyte

DOI: 10.3233/JAD-221064

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-20, 2023

Authors: Guo, Xiaodi | Zhang, Guoxin | Peng, Qinyu | Huang, Liqin | Zhang, Zhaohui | Zhang, Zhentao

Article Type: Review Article

Abstract: Meningeal lymphatic vessels (mLVs), the functional lymphatic system present in the meninges, are the key drainage route responsible for the clearance of molecules, immune cells, and cellular debris from the cerebrospinal fluid and interstitial fluid into deep cervical lymph nodes. Aging and ApoE4, the two most important risk factors for Alzheimer’s disease (AD), induce mLV dysfunction, decrease cerebrospinal fluid influx and outflux, and exacerbate amyloid pathology and cognitive dysfunction. Dysfunction of mLVs results in the deposition of metabolic products, accelerates neuroinflammation, and promotes the release of pro-inflammatory cytokines in the brain. Thus, mLVs represent a novel therapeutic target for treating …neurodegenerative and neuroinflammatory diseases. This review aims to summarize the structure and function of mLVs and to discuss the potential effect of aging and ApoE4 on mLV dysfunction, as well as their roles in the pathogenesis of AD. Show more

Keywords: Alzheimer’s disease, amyloid-β, Apolipoprotein E4, meningeal lymphatic vessels, tau

DOI: 10.3233/JAD-221016

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-12, 2022

Authors: Daly, Timothy | Henry, Vincent | Bourdenx, Mathieu

Article Type: Review Article

Abstract: Background: Many putative causes and risk factors have been associated with outcomes in Alzheimer’s disease (AD) but all attempts at disease-modifying treatment have failed to be clinically significant. Efforts to address this “association—intervention” mismatch have tended to focus on the novel design of interventions. Objective: Here, we instead deal with the notion of association in depth. We introduce the concept of disease-associated process (DAP) as a flexible concept that can unite different areas of study of AD from genetics to epidemiology to identify disease-modifying targets. Methods: We sort DAPs using three properties: specificity for AD, frequency …in patients, and pathogenic intensity for dementia before using a literature review to apply these properties in three ways. Firstly, we describe and visualize known DAPs. Secondly, we exemplify qualitative specificity analysis with the DAPs of tau protein pathology and autophagy to reveal their differential implication in AD. Finally, we use DAP properties to define the terms “risk factor,” “cause,” and “biomarker.” Results: We show how DAPs fit into our collaborative disease ontology, the Alzheimer’s Disease-Associated Processes and Targets (ADAPT) ontology. We argue that our theoretical system can serve as a democratic research forum, offering a more biologically adequate view of dementia than reductionist models. Conclusion: The ADAPT ontology is a tool that could help to ground debates around priority setting using objective criteria for the identifying of targets in AD. Further efforts are needed to address issues of how biomedical research into AD is prioritized and funded. Show more

Keywords: Alzheimer’s disease, association, autophagy, biomarker, cause, disease ontology, intervention, risk factors, specificity, tau

DOI: 10.3233/JAD-221004

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-10, 2022

Authors: Ishabiyi, Felix Oluwasegun | Ogidi, James | Olukade, Baliqis Adejoke | Amorha, Chizoba Christabel | El-Sharkawy, Lina Y. | Okolo, Chukwuemeka Calistus | Adeniyi, Titilope Mary | Atasie, Nkechi Hope | Ibrahim, Abdulwasiu | Balogun, Toheeb Adewale

Article Type: Research Article

Abstract: Background: The development of therapeutic agents against Alzheimer’s disease (AD) has stalled recently. Drug candidates targeting amyloid-β (Aβ) deposition have often failed clinical trials at different stages, prompting the search for novel targets for AD therapy. The NLRP3 inflammasome is an integral part of innate immunity, contributing to neuroinflammation and AD pathophysiology. Thus, it has become a promising new target for AD therapy. Objective: The study sought to study the potential of bioactive compounds derived from Azadirachta indica to inhibit the NLRP3 protein implicated in the pathophysiology of AD. Methods: Structural bioinformatics via molecular docking …and density functional theory (DFT) analysis was utilized for the identification of novel NLRP3 inhibitors from A. indica bioactive compounds. The compounds were further subjected to pharmacokinetic and drug-likeness analysis. Results obtained from the compounds were compared against that of oridonin, a known NLRP3 inhibitor. Results: The studied compounds optimally saturated the binding site of the NLRP3 NACHT domain, forming principal interactions with the different amino acids at its binding site. The studied compounds also demonstrated better bioactivity and chemical reactivity as ascertained by DFT analysis and all the compounds except 7-desacetyl-7-benzoylazadiradione, which had two violations, conformed to Lipinski’s rule of five. Conclusion: In silico studies show that A. indica derived compounds have better inhibitory potential against NLRP3 and better pharmacokinetic profiles when compared with the reference ligand (oridonin). These compounds are thus proposed as novel NLRP3 inhibitors for the treatment of AD. Further wetlab studies are needed to confirm the potency of the studied compounds. Show more

Keywords: Alzheimer’s disease, Azadiracta indica, density functional theory, inflammasomes, molecular docking, NLRP3

DOI: 10.3233/JAD-221020

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-19, 2023

Authors: Basha, SK Chand | Ramaiah, Mekala Janaki | Kosagisharaf, Jagannatha Rao

Article Type: Review Article

Abstract: Alzheimer’s disease (AD) is a complex neurodegenerative disorder involving heterogenous pathophysiological characteristics, which has become a challenge to therapeutics. The major pathophysiology of AD comprises amyloid-β (Aβ), tau, oxidative stress, and apoptosis. Recent studies indicate the significance of Triggering receptor expressed on myeloid cells 2 (TREM2) and its mutant variants in AD. TREM2 are the transmembrane receptors of microglial cells that performs a broad range of physiological cell processes. Phagocytosis of Aβ is one of the physiological roles of TREM, which plays a pivotal role in AD progression. R47H, a mutant variant of TREM2, increases the risk of AD by …impairing TREM2–Aβ binding. Inconclusive evidence regarding the TREM2 signaling cascade mechanism of Aβ phagocytosis motivates the current review to propose a new hypothesis. The review systematically assesses the cross talk between TREM2 and other AD pathological domains and the influence of TREM2 on amyloid and tau seeding. Disease associated microglia (DAM), a novel state of microglia with unique transcriptional and functional signatures reported in neurodegenerative conditions, also depend on the TREM2 pathway for its differentiation. DAM is suggested to have a neuroprotective role. We hypothesize that TREM2, along with its signaling adaptors and endogenous proteins, play a key role in ameliorating Aβ clearance. We indicate that TREM2 has the potential to ameliorate the Aβ burden, though with differential clearance ability and may act as a potential therapeutic target. Show more

Keywords: Alzheimer’s disease, amyloid-β, DAP10, DAP12, disease associated microglia, microglia, neurodegeneration, PLCγ2, DAM, R47H, TREM2

DOI: 10.3233/JAD-221070

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-15, 2023

Authors: Bian, Zhihong | Yu, Haibo | Hu, Xinran | Bian, Yuting | Sun, Hongming | Tadokoro, Koh | Takemoto, Mami | Yunoki, Taijun | Nakano, Yumiko | Fukui, Yusuke | Morihara, Ryuta | Abe, Koji | Yamashita, Toru

Article Type: Research Article

Abstract: Background: NADPH oxidase 2 (NOX2) is an important source of reactive oxygen species (ROS). Activated NOX2 may contribute to Alzheimer’s disease (AD). Our previous studies showed that a novel vitamin E mixture, Tocovid, had potential neuroprotective effects in a stroke mice model and an AD cell model. Objective: The aim of this study was two-fold: to assess whether long-term Tocovid treatment can regulate NOX2, and the therapeutic effects of long-term administration of Tocovid to an AD mice model. Methods: Therapeutic effects of long-term administration of Tocovid (200 mg/kg /day) on an Aβ-overexpressed transgenic AD mice model (APP23, …n  = 8) was investigated. The therapeutic effect of Tocovid in 16-month-old mice compared with the no-treatment APP23 group (n  = 9) was assessed. Results: Tocovid treatment strongly improved motor and memory deficits of APP23 mice by attenuating NOX2 expression, oxidative stress, neuroinflammation, neurovascular unit dysfunction, synaptic alteration, and Aβ deposition after 16 months. Conclusion: These findings suggest that NOX2 is a potential target in AD pathology. Long-term administration of Tocovid may be a promising candidate for AD treatment. Show more

Keywords: Alzheimer’s disease, cerebral amyloid angiopathy, NOX2, oxidative stress, Tocovid

DOI: 10.3233/JAD-220761

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-11, 2022

Authors: Huang, Li | Lu, Zhaogang | Zhang, Hexin | Wen, Hongyong | Li, Zongji | Liu, Qibing | Wang, Rui

Article Type: Review Article

Abstract: Alzheimer’s disease (AD) is one of the most common neurodegenerative diseases worldwide. The accumulation of amyloid-β (Aβ) protein and plaque formation in the brain are two major causes of AD. Interestingly, growing evidence demonstrates that the gut flora can alleviate AD by affecting amyloid production and metabolism. However, the underlying mechanism remains largely unknown. This review will discuss the possible association between the gut flora and Aβ in an attempt to provide novel therapeutic directions for AD treatment based on the regulatory effect of Aβ on the gut flora.

Keywords: Alzheimer’s disease, amyloid-β, colitis, insulin resistance, intestinal flora, neuroinflammation

DOI: 10.3233/JAD-220651

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-13, 2022

Authors: Liang, Jingjing | LeFleur, Bonnie | Hussainy, Sadiya | Perry, George

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) is the most common form of dementia in the elderly marked by central nervous system (CNS) neuronal loss and amyloid plaques. FAM222A , encoding an amyloid plaque core protein, is an AD brain atrophy susceptibility gene that mediates amyloid-β aggregation. However, the expression interplay between FAM222A and other AD-related pathway genes is unclear. Objective: Our goal was to study FAM222A ’s whole-genome co-expression profile in multiple tissues and investigate its interplay with other AD-related genes. Methods: We analyzed gene expression correlations in Genotype-Tissue Expression (GTEx) tissues to identify FAM222A co-expressed …genes and performed functional enrichment analysis on identified genes in CNS system. Results: Genome-wide gene expression profiling identified 673 genes significantly correlated with FAM222A (p  <  2.5×10–6 ) in 48 human tissues, including 298 from 13 CNS tissues. Functional enrichment analysis revealed that FAM222A co-expressed CNS genes were enriched in multiple AD-related pathways. Gene co-expression network analysis for identified genes in each brain region predicted other disease associated genes with similar biological function. Furthermore, co-expression of 25 out of 31 AD-related pathways genes with FAM222A was replicated in brain samples from 107 aged subjects from the Aging, Dementia and TBI Study. Conclusion: This gene co-expression study identified multiple AD-related genes that are associated with FAM222A , indicating that FAM222A and AD-associated genes can be active simultaneously in similar biological processes, providing evidence that supports the association of FAM222A with AD. Show more

Keywords: Alzheimer’s disease, FAM222A, gene co-expression network analysis, neurodegeneration, transcriptomics

DOI: 10.3233/JAD-221241

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-15, 2023

Authors: Liew, Yee | Retinasamy, Thaarvena | Arulsamy, Alina | Ali, Idrish | Jones, Nigel C. | O’Brien, Terence J. | Shaikh, Mohd Farooq

Article Type: Systematic Review

Abstract: Background: Neuroinflammation is an innate immunological response of the central nervous system that may be induced by a brain insult and chronic neurodegenerative conditions. Recent research has shown that neuroinflammation may contribute to the initiation of Alzheimer’s disease (AD) pathogenesis and associated epileptogenesis. Objective: This systematic review aimed to investigate the available literature on the shared molecular mechanisms of neuroinflammation in AD and epilepsy. Methods: The search included in this systematic review was obtained from 5 established databases. A total of 2,760 articles were screened according to inclusion criteria. Articles related to the modulation of the …inflammatory biomarkers commonly associated with the progression of AD and epilepsy in all populations were included in this review. Results: Only 7 articles met these criteria and were chosen for further analysis. Selected studies include both in vitro and in vivo research conducted on rodents. Several neuroinflammatory biomarkers were reported to be involved in the cross-talk between AD and epilepsy. Conclusion: Neuroinflammation was directly associated with the advancement of AD and epilepsy in populations compared to those with either AD or epilepsy. However, more studies focusing on common inflammatory biomarkers are required to develop standardized monitoring guidelines to prevent the manifestation of epilepsy and delay the progression of AD in patients. Show more

Keywords: Alzheimer’s disease, epilepsy, epileptogenesis, neurodegeneration, neuroinflammation, neuropathology

DOI: 10.3233/JAD-230059

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-13, 2023

Authors: Chen, Xiaokun | Jiang, Shenzhong | Wang, Renzhi | Bao, Xinjie | Li, Yongning

Article Type: Review Article

Abstract: Alzheimer’s disease (AD), a progressive dementia, is one of the world’s most dangerous and debilitating diseases. Clinical trial results of amyloid-β (Aβ) and tau regulators based on the pretext of straightforward amyloid and tau immunotherapy were disappointing. There are currently no effective strategies for slowing the progression of AD. Further understanding of the mechanisms underlying AD and the development of novel therapeutic options are critical. Neurogenesis is impaired in AD, which contributes to memory deficits. Transplanted neural stem cells (NSCs) can regenerate degraded cholinergic neurons, and new neurons derived from NSCs can form synaptic connections with neighboring neurons. In theory, …employing NSCs to replace and restore damaged cholinergic neurons and brain connections may offer new treatment options for AD. However there remain barriers to surmount before NSC-based therapy can be used clinically. The objective of this article is to describe recent advances in the treatment of AD models and clinical trials involving NSCs. In addition, we discuss the challenges and prospects associated with cell transplant therapy for AD. Show more

Keywords: Alzheimer’s disease, cell therapy, neural stem cells, neurodegenerative disease, transplantation

DOI: 10.3233/JAD-220721

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-14, 2023