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@PHDTHESIS{Islam:282310,
author = {Islam, Rezaul},
title = {{E}pigenetic {B}iomarker and {T}herapeutic {I}ntervention
for {D}ementia},
school = {Georg-August-Universität Göttingen},
type = {Dissertation},
reportid = {DZNE-2025-01280},
pages = {126 p.},
year = {2021},
note = {Dissertation, Georg-August-Universität Göttingen, 2021},
abstract = {Dementia is the most significant health challenge in modern
times, currently affecting over 50 million people worldwide.
The number of people afflicted with this disorder is on the
rise and expected to double by 2025. Causative and
symptomatic treatments of this disease have been so far
unsuccessful.This is partly due to the fact that patients
are only diagnosed with dementia at an advanced stage, when
a massive neuronal loss has already manifested. There is
substantial evidence memory impairment is preceded by
molecular changes that happen years before the onset of
cognitive decline. Therefore, there is an urgent need for
biomarkers to diagnose early changes in the brain, which
would allow clinicians to intervene therapeutically at an
earlier phase of the disease. Moreover, it is equally
important to study the underlying mechanisms of risk factors
that might precipitate these early changes in the brain.
Management of those risk factors may significantly reduce
the progression of dementia or even prevent the onset of the
disease. Therefore, in this cumulative thesis, I first
tested the hypothesis that microRNAs in blood could be
potential early diagnostic biomarkers for dementia. By using
human cross-sectional and mouse longitudinal data, coupled
with advanced multi-step systems biology approach, I report
a blood-based “microRNA signature” that can inform about
early cognitive decline in healthy and pathological
conditions. Intriguingly, by manipulating the level of one
of the signature microRNAs, I could improve memory in
cognitively impaired mice. These data suggest that the
“microRNA signature” that I report can not only be used
as a diagnostic marker but also as a therapy to manage
cognitive deficits in early dementia. In addition, I
investigated how cardiac failure, a risk factor of dementia,
could affect brain functions at the molecular level. By
using transgenic mice with failing hearts, I report
down-regulation of memory-related genes in the hippocampus
leads to cognitive deficits in transgenic mice. Analyses of
genome-wide distribution of H3K4me3 reveal that reduced
levels of H3K4me3 at the promoters of genes may underpin
cognitive changes. Consistently, through oral administration
of SAHA, an inhibitor of HDAC, I delineate that the observed
cognitive deficits can be rescued. At the molecular level,
SAHA could partially restore both microRNAome and RNAome,
highlighting its potential as a therapeutic intervention to
ameliorate cognitive deficits following heart failure. Both
of these studies provide key insight to molecular
underpinnings and therapeutic interventions of early
dementia. While epigenetic biomarker based on microRNAs
could be useful to stratify individuals at risk of
developing dementia, epigenetic drugs could be suitable
strategy to restore memory and attenuate the future risk of
dementia.},
cin = {AG Fischer},
cid = {I:(DE-2719)1410002},
pnm = {352 - Disease Mechanisms (POF4-352)},
pid = {G:(DE-HGF)POF4-352},
typ = {PUB:(DE-HGF)11},
url = {https://pub.dzne.de/record/282310},
}