scholarly journals Disease Mechanisms and Therapeutic Approaches in C9orf72 ALS-FTD

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 601
Author(s):  
Keith Mayl ◽  
Christopher E. Shaw ◽  
Youn-Bok Lee
Keyword(s):  
The Body ◽  
The Novel ◽  
Therapeutic Approaches ◽  
Gain Of Function ◽  
Pathogenic Mechanisms ◽  
Hexanucleotide Repeat ◽  
Primary Driver ◽  
Hexanucleotide Repeat Expansion ◽  
Expansion Mutation ◽  
Lateral Sclerosis

A hexanucleotide repeat expansion mutation in the first intron of C9orf72 is the most common known genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Since the discovery in 2011, numerous pathogenic mechanisms, including both loss and gain of function, have been proposed. The body of work overall suggests that toxic gain of function arising from bidirectionally transcribed repeat RNA is likely to be the primary driver of disease. In this review, we outline the key pathogenic mechanisms that have been proposed to date and discuss some of the novel therapeutic approaches currently in development.

Healthy Gut, Healthy Brain: The Gut Microbiome in Neurodegenerative Disorders

2020 ◽  
Vol 20 (13) ◽  
pp. 1142-1153 ◽  
Author(s):  
Sreyashi Chandra ◽  
Md. Tanjim Alam ◽  
Jhilik Dey ◽  
Baby C. Pulikkaparambil Sasidharan ◽  
Upasana Ray ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Neurodegenerative Disorders ◽  
The Body ◽  
Therapeutic Approaches ◽  
Cns Disorders ◽  
Physiological Conditions ◽  
Pathological Conditions ◽  
The Central Nervous System ◽  
Present Understanding ◽  
Lateral Sclerosis

Background: The central nervous system (CNS) known to regulate the physiological conditions of human body, also itself gets dynamically regulated by both the physiological as well as pathological conditions of the body. These conditions get changed quite often, and often involve changes introduced into the gut microbiota which, as studies are revealing, directly modulate the CNS via a crosstalk. This cross-talk between the gut microbiota and CNS, i.e., the gut-brain axis (GBA), plays a major role in the pathogenesis of many neurodegenerative disorders such as Parkinson’s disease (PD), Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS) and Huntington’s disease (HD). Objective: We aim to discuss how gut microbiota, through GBA, regulate neurodegenerative disorders such as PD, AD, ALS, MS and HD. Methods: In this review, we have discussed the present understanding of the role played by the gut microbiota in neurodegenerative disorders and emphasized the probable therapeutic approaches being explored to treat them. Results: In the first part, we introduce the GBA and its relevance, followed by the changes occurring in the GBA during neurodegenerative disorders and then further discuss its role in the pathogenesis of these diseases. Finally, we discuss its applications in possible therapeutics of these diseases and the current research improvements being made to better investigate this interaction. Conclusion: We concluded that alterations in the intestinal microbiota modulate various activities that could potentially lead to CNS disorders through interactions via the GBA.

scholarly journals C9orf72 Hexanucleotide Repeat Expansion and Guam Amyotrophic Lateral Sclerosis–Parkinsonism-Dementia Complex

2013 ◽  
Vol 70 (6) ◽  
pp. 742 ◽  
Author(s):  
Beth A. Dombroski ◽  
Douglas R. Galasko ◽  
Ignacio F. Mata ◽  
Cyrus P. Zabetian ◽  
Ulla-Katrina Craig ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Repeat Expansion ◽  
Hexanucleotide Repeat ◽  
Hexanucleotide Repeat Expansion ◽  
Lateral Sclerosis

scholarly journals Who and Why? Requests for Presymptomatic Genetic Testing for Amyotrophic Lateral Sclerosis/Frontotemporal Dementia vs Huntington Disease

2020 ◽  
Vol 7 (1) ◽  
pp. e538
Author(s):  
Maria del Mar Amador ◽  
Marcela Gargiulo ◽  
Christilla Boucher ◽  
Ariane Herson ◽  
Stéphanie Staraci ◽  
...  
Keyword(s):  
At Risk ◽  
Amyotrophic Lateral Sclerosis ◽  
Frontotemporal Dementia ◽  
Huntington Disease ◽  
Dropout Rate ◽  
Time Frame ◽  
Hexanucleotide Repeat ◽  
Hexanucleotide Repeat Expansion ◽  
Added Uncertainty ◽  
Lateral Sclerosis

ObjectiveWe aimed to describe the population of subjects seeking presymptomatic counseling for amyotrophic lateral sclerosis and/or frontotemporal dementia (ALS/FTD) and compared them with those demanding the well-established presymptomatic test for Huntington disease (HD).MethodsWe retrospectively examined the requests of a cohort of individuals at risk of familial ALS/FTD and 1 at risk of HD over the same time frame of 11 years. The individuals were seen in the referral center of our neurogenetics unit.ResultsOf the 106 presymptomatic testing (PT) requests from subjects at risk of ALS/FTD, 65% were seen in the last 3 years. Over two-thirds of the subjects were at risk of carrying mutations responsible for ALS, FTD, or both. Sixty-two percent of the subjects came from families with a known hexanucleotide repeat expansion in C9ORF72. During the same period, we counseled 840 subjects at risk of HD. Subjects at risk of ALS/FTD had the presymptomatic test significantly sooner after being aware of their risk, but were older than those at risk of HD. The youngest subjects requesting the test had the highest disease load in the family (p < 0.05).ConclusionsDemands for PT for ALS/FTD have been increasingly growing, particularly since the discovery of the C9ORF72 gene. The major specificity of the genetic counseling for these diseases is the unpredictability of the clinical phenotype for most of the genes involved. Awareness of this added uncertainty does not prevent individuals from taking the test, as the dropout rate is not higher than that for HD.

scholarly journals TFEB/Mitf links impaired nuclear import to autophagolysosomal dysfunction in C9-ALS

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Kathleen M Cunningham ◽  
Kirstin Maulding ◽  
Kai Ruan ◽  
Mumine Senturk ◽  
Jonathan C Grima ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Amyotrophic Lateral Sclerosis ◽  
Nuclear Import ◽  
Transcriptional Regulator ◽  
Nucleocytoplasmic Transport ◽  
Repeat Expansion ◽  
Disease Pathogenesis ◽  
Hexanucleotide Repeat ◽  
Hexanucleotide Repeat Expansion ◽  
Lateral Sclerosis

Disrupted nucleocytoplasmic transport (NCT) has been implicated in neurodegenerative disease pathogenesis; however, the mechanisms by which disrupted NCT causes neurodegeneration remain unclear. In a Drosophila screen, we identified ref(2)P/p62, a key regulator of autophagy, as a potent suppressor of neurodegeneration caused by the GGGGCC hexanucleotide repeat expansion (G4C2 HRE) in C9orf72 that causes amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). We found that p62 is increased and forms ubiquitinated aggregates due to decreased autophagic cargo degradation. Immunofluorescence and electron microscopy of Drosophila tissues demonstrate an accumulation of lysosome-like organelles that precedes neurodegeneration. These phenotypes are partially caused by cytoplasmic mislocalization of Mitf/TFEB, a key transcriptional regulator of autophagolysosomal function. Additionally, TFEB is mislocalized and downregulated in human cells expressing GGGGCC repeats and in C9-ALS patient motor cortex. Our data suggest that the C9orf72-HRE impairs Mitf/TFEB nuclear import, thereby disrupting autophagy and exacerbating proteostasis defects in C9-ALS/FTD.

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