scholarly journals LRRK2p.G2019S Mutation Is Not Common among Alzheimer’s Disease Patients in Brazil

2009 ◽  
Vol 27 (1) ◽  
pp. 13-16 ◽  
Author(s):  
Cíntia Barros Santos-Rebouças ◽  
Cláudia Bueno Abdalla ◽  
Paloma Águia Martins ◽  
Fábio José Rodrigues Baldi ◽  
Jussara Mendonça Santos ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Linkage Peak ◽  
Lrrk2 Mutation ◽  
Cellular Processes ◽  
New Information ◽  
Lrrk2 Gene ◽  
Different Populations

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have emerged as a potential common cause for both sporadic and familial Parkinson’s Disease (PD) in different populations. The pleomorphic features exhibited by LRRK2 mutation carriers and the central role of Lrrk2 protein in the proper functioning of central nervous system suggest that mutations in this protein might be involved in multiple cellular processes leading to other neurodegenerative disorders than PD. The location of LRRK2 gene on chromosome 12, close to a linkage peak for familial late-onset Alzheimer’s Disease (AD), highlights that LRRK2 mutations might be involved in AD pathogenesis. We screened the most common LRRK2 mutation (p.G2019S) in a series of 180 consecutive patients clinically diagnosed with Alzheimer Disease (AD). We identified the p.G2019S in one AD patient with no PD signs, indicating that this mutation is not a common etiological factor for AD in our population (0.5%), corroborating recent data found in Norwegian, North American, Chinese and Italian populations. Nevertheless, these observations together with new information about the Lrrk2 critical multifunctionality do not rule out the possible influence of other variants within LRRK2 in AD, so that other screenings focusing in the whole extension of the LRRK2 using larger sized confirmed AD sample are urgently needed.

Exploring the Role of Aggregated Proteomes in the Pathogenesis of Alzheimer’s Disease

2020 ◽  
Vol 21 (12) ◽  
pp. 1164-1173
Author(s):  
Siju Ellickal Narayanan ◽  
Nikhila Sekhar ◽  
Rajalakshmi Ganesan Rajamma ◽  
Akash Marathakam ◽  
Abdullah Al Mamun ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Early Onset ◽  
Late Onset ◽  
Precursor Protein ◽  
Brain Disorder ◽  
Amyloid Aβ ◽  
T Tau

: Alzheimer’s disease (AD) is a progressive brain disorder and one of the most common causes of dementia and death. AD can be of two types; early-onset and late-onset, where late-onset AD occurs sporadically while early-onset AD results from a mutation in any of the three genes that include amyloid precursor protein (APP), presenilin 1 (PSEN 1) and presenilin 2 (PSEN 2). Biologically, AD is defined by the presence of the distinct neuropathological profile that consists of the extracellular β-amyloid (Aβ) deposition in the form of diffuse neuritic plaques, intraneuronal neurofibrillary tangles (NFTs) and neuropil threads; in dystrophic neuritis, consisting of aggregated hyperphosphorylated tau protein. Elevated levels of (Aβ), total tau (t-tau) and phosphorylated tau (ptau) in cerebrospinal fluid (CSF) have become an important biomarker for the identification of this neurodegenerative disease. The aggregation of Aβ peptide derived from amyloid precursor protein initiates a series of events that involve inflammation, tau hyperphosphorylation and its deposition, in addition to synaptic dysfunction and neurodegeneration, ultimately resulting in dementia. The current review focuses on the role of proteomes in the pathogenesis of AD.

The Role of Microglia in Sporadic Alzheimer’s Disease

2021 ◽  
Vol 79 (3) ◽  
pp. 961-968
Author(s):  
Wolfgang J. Streit ◽  
Habibeh Khoshbouei ◽  
Ingo Bechmann
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Genetic Mutations ◽  
Sporadic Alzheimer’S Disease ◽  
Immune Effector ◽  
Effector Cells ◽  
Immune Effector Cells ◽  
Amyloid Cascade

Microglia constitute the brain’s immune system and their involvement in Alzheimer’s disease has been discussed. Commonly, and in line with the amyloid/neuroinflammation cascade hypothesis, microglia have been portrayed as potentially dangerous immune effector cells thought to be overactivated by amyloid and producing neurotoxic inflammatory mediators that lead to neurofibrillary degeneration. We disagree with this theory and offer as an alternative the microglial dysfunction theory stating that microglia become impaired in their normally neuroprotective roles because of aging, i.e., they become senescent and aging neurons degenerate because they lack the needed microglial support for their survival. Thus, while the amyloid cascade theory relies primarily on genetic data, the dysfunction theory incorporates aging as a critical etiological factor. Aging is the greatest risk factor for the sporadic (late-onset) and most common form of Alzheimer’s disease, where fully penetrant genetic mutations are absent. In this review, we lay out and discuss the human evidence that supports senescent microglial dysfunction and conflicts with the amyloid/neuroinflammation idea.

scholarly journals Autophagy and mitophagy biomarkers are reduced in sera of patients with Alzheimer’s disease and mild cognitive impairment

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Massimiliano Castellazzi ◽  
Simone Patergnani ◽  
Mariapina Donadio ◽  
Carlotta Giorgi ◽  
Massimo Bonora ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Late Onset ◽  
Memory Loss ◽  
Serum Levels ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Cellular Processes

AbstractDementia is a neurocognitive disorder characterized by a progressive memory loss and impairment in cognitive and functional abilities. Autophagy and mitophagy are two important cellular processes by which the damaged intracellular components are degraded by lysosomes. To investigate the contribution of autophagy and mitophagy in degenerative diseases, we investigated the serum levels of specific autophagic markers (ATG5 protein) and mitophagic markers (Parkin protein) in a population of older patients by enzyme-linked immunosorbent assay. Two hundred elderly (≥65 years) outpatients were included in the study: 40 (20 F and 20 M) with mild-moderate late onset Alzheimer’s disease (AD); 40 (20 F and 20 M) affected by vascular dementia (VAD); 40 with mild cognitive impairment (MCI); 40 (20 F and 20 M) with “mixed” dementia (MD); 40 subjects without signs of cognitive impairment were included as sex-matched controls. Our data indicated that, in serum samples, ATG5 and Parkin were both elevated in controls, and that VAD compared with AD, MCI and MD (all p < 0.01). Patients affected by AD, MD, and MCI showed significantly reduced circulating levels of both ATG5 and Parkin compared to healthy controls and VAD individuals, reflecting a significant down-regulation of autophagy and mitophagy pathways in these groups of patients. The measurement of serum levels of ATG5 and Parkin may represent an easily accessible diagnostic tool for the early monitoring of patients with cognitive decline.

scholarly journals Association Study of Genetic Variants inCDKN2A/CDKN2BGenes/Loci with Late-Onset Alzheimer's Disease

2011 ◽  
Vol 2011 ◽  
pp. 1-4
Author(s):  
Andrea Tedde ◽  
Irene Piaceri ◽  
Silvia Bagnoli ◽  
Ersilia Lucenteforte ◽  
Uwe Ueberham ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Genetic Variants ◽  
Genetic Variant ◽  
Case Control Study ◽  
Late Onset ◽  
Common Genetic Variant ◽  
Genome Wide ◽  
Control Study

Alzheimer's disease (AD) is the most common form of dementia clinically characterized by progressive impairment of memory and other cognitive functions. Many genetic researches in AD identified one common genetic variant (ε4) in Apolipoprotein E (APOE) gene as a risk factor for the disease. Two independent genome-wide studies demonstrated a new locus on chromosome 9p21.3 implicated in Late-Onset Alzheimer's Disease (LOAD) susceptibility in Caucasians. In the present study, we investigated the role of three SNP's in theCDKN2Agene (rs15515, rs3731246, and rs3731211) and one in theCDKN2Bgene (rs598664) located in 9p21.3 using an association case-control study carried out in a group of Caucasian subjects including 238 LOAD cases and 250 controls. The role ofCDKN2AandCDKN2Bgenetic variants in AD is not confirmed in our LOAD patients, and further studies are needed to elucidate the role of these genes in the susceptibility of AD.

scholarly journals Genome research in pre-dementia stages of Alzheimer's disease

2016 ◽  
Vol 18 ◽  
Author(s):  
Sonia Moreno-Grau ◽  
Agustín Ruiz
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Subjective Cognitive Decline ◽  
Genetic Profile ◽  
Amyloid Deposits ◽  
Dementia Risk ◽  
Meta Analyses ◽  
Brain Insults

Genetic characterization of individuals at risk of Alzheimer's disease (AD), i.e. people having amyloid deposits in the brain without symptoms, people suffering from subjective cognitive decline (SCD) or mild cognitive impairment (MCI), has spurred the interests of researchers. However, their pre-dementia genetic profile remains mostly unexplored. In this study, we reviewed the loci related to phenotypes of AD, MCI and SCD from literature and performed the first meta-analyses evaluating the role of apolipoprotein E (APOE) in the risk of conversion from a healthy status to MCI and SCD. For AD dementia risk, an increased number of loci have been identified; to date, 28 genes have been associated with Late Onset AD. In MCI syndrome,APOEis confirmed as a pheno-conversion factor leading from MCI to AD, and clusterin is a promising candidate. Additionally, our meta-analyses revealedAPOEas genetic risk factor to convert from a healthy status to MCI [OR = 1.849 (1.587–2.153);P = 2.80  × 10−15] and to a lesser extent from healthy status to SCD [OR = 1.151 (1.015–1.304);P = 0.028]. Thus, we believe that genetic studies in longitudinal SCD and MCI series may provide new therapeutic targets and improve the existing knowledge of AD. This type of studies must be completed on healthy subjects to better understand the natural disease resistance to brain insults and neurodegeneration.

scholarly journals Exploring the role of common regulatory variants in the etiology of late-onset Alzheimer’s disease

2012 ◽  
Vol 7 (Suppl 1) ◽  
pp. S22
Author(s):  
Hao Wang ◽  
Min Zhu ◽  
Jian Wang ◽  
Yue Sun ◽  
Yu Tao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Regulatory Variants

scholarly journals Probing the role of PPARγ in the regulation of late-onset Alzheimer’s disease-associated genes

PLoS ONE ◽  
2018 ◽  
Vol 13 (5) ◽  
pp. e0196943 ◽  
Author(s):  
Julio Barrera ◽  
Shobana Subramanian ◽  
Ornit Chiba-Falek
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Disease Associated Genes

scholarly journals Late onset epilepsy and Alzheimer’s disease: exploring the dual pathogenic role of amyloid-β

Brain ◽  
2018 ◽  
Vol 141 (8) ◽  
pp. e60-e60 ◽  
Author(s):  
Cinzia Costa ◽  
Michele Romoli ◽  
Paolo Calabresi
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Amyloid Β ◽  
Pathogenic Role

scholarly journals Regulation of cell distancing in peri-plaque glial nets by Plexin-B1 affects glial activation and amyloid compaction in Alzheimer’s disease

2021 ◽  
Author(s):  
Roland Friedel ◽  
Yong Huang ◽  
Minghui Wang ◽  
Shalaka Wahane ◽  
Mitzy Ríos de Anda ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Amyloid Plaque ◽  
Reactive Astrocytes ◽  
Glial Activation ◽  
Plaque Burden ◽  
Aβ Amyloid ◽  
Underlying Mechanisms

Abstract Communication between glial cells has a profound effect on the pathophysiology of Alzheimer’s disease (AD), but the underlying mechanisms remain unclear. Here, we reveal a role of reactive astrocytes in enforcing cell distancing in the glial nets surrounding amyloid plaques, which restricts microglial coverage of Aβ, a prerequisite to detect and engulf amyloid deposits. This process is mediated through guidance receptor Plexin-B1, which we identified as a key network regulator of late-onset AD. We show that Plexin-B1 is robustly upregulated in plaque-associated astrocytes in a corona-like pattern, and its expression levels correlate with plaque burden and disease severity in AD patients. In APP/PS1 mice, an amyloidogenic model of AD, removing Plexin-B1 led to smaller peri-plaque glial nets with relaxed cell distancing and enhanced glial coverage of Aβ plaques, as well as transcriptional changes in both reactive astrocytes and disease-associated microglia that are linked to glial activation and amyloid clearance. Furthermore, amyloid plaque burden was lowered, together with a shift towards dense-core plaques and reduced neuritic dystrophy. Our data thus support a role of Plexin-B1 in controlling glial net structure by imposing cell distancing, leading to poor glial coverage of Aβ, reduced amyloid clearance and compaction. Relaxing cell distancing by targeting guidance receptors may present an alternative strategy to alleviate neuroinflammation in AD by improving glial coverage of Aβ amyloid and plaque compaction.

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