20.500.12556/RUNG-4778-bbfefcf0-a926-e473-9d6b-9286c5766144
Dissecting the role of REEP1 in preventing Tau-mediated neurodegeneration in a D.melanogaster Alzheimer's disease model
Ugotavljanje preventivne vloge proteina REEP1 v nastanku s Tau povezane nevrodegeneracije v modelnem sistemu Alzheimerjeve bolezni D.melanogaster
Tau is natively an unfolded protein that promotes the assembly and the stability of the
axonal microtubules in the central nervous system. Increased formation of Tau protein
aggregates has been causatively implicated in several neurodegenerative diseases called
tauopathies. In the present study, we used the Drosophila melanogaster system to express
the longest isoform of human Tau (2N4R) in the nervous system of adult flies, recreating
the main features of the human pathology. Herein, this Tau-mediated neurodegeneration
model was used as a platform to perform genetic screenings to identify putative modifiers
of Tau toxicity. Our strategy exploited the modulation of genes considered as risk factors of
Alzheimer’s disease (AD), Frontotemporal Dementias and other neurodegenerative
diseases by RNA interference in vivo. This approach allowed us to identify a new gene
which participates in the neuronal response against Tau induced neurotoxicity in
Drosophila: D-Reep1, homologue of human REEP1 gene (h-Reep1). D-Reep1 knockout flies
showed no apparent phenotypes in physiological growing and developmental conditions,
however, they showed peculiar sensitivity to stress conditions. In addition, D-Reep1
knockout enhanced the neurodegeneration mediated by Tau expression in Drosophila eyes.
On the contrary, the overexpression of UAS-D-Reep1 and UAS-h-Reep1 abolished the
typical rough eye phenotype induced by the presence of Tau. The Co-expression of D-Reep1
in Tau backgrounds did not alter the phosphorylation pattern of this protein while, the
presence of D-Reep1 seemed to prevent the formation of Tau aggregates in vivo. Thus, the
data support the idea that D-Reep1 exerts a protective role on Tau induced toxicity which is
independent of its phosphorylation status. In this work, I analysed the mechanisms behind
the neuroprotective role of D-Reep1 and, in particular, I found that REEP1 is involved in the
regulation of the unfolded protein response (UPR) through the PERK-ATF4 cascade within
the ER. By the activation of this pathway, the neurotoxic aggregates of Tau are removed
from Drosophila neuronal tissues rescuing the normal characteristics of the affected
tissues. Evidences also suggest that the activation of autophagy was behind the removal of
Tau aggregates, providing new molecular information about the physiological role of D
Reep1 in the nervous system.
V človeškem telesu je Tau prisoten kot nezvit protein in sodeluje pri združevanju in
stabilizaciji aksonskih mikrotubulov v centralnem živčnem sistemu. Agregati proteina Tau so
karakteristika številnih nevrodegenerativnih bolezni (t.i. tauopatije). Za vzpostavitev
simptomov, ki so prisotni pri nevrodegenerativnih boleznih, smo v živčevju odrasle živali D.
melanogaster izrazili najdaljšo izoformo humanega proteina Tau (2N4R). Model smo
uporabili kot osnovo za genetski pregled domnevnih modifikatorjev toksičnosti proteina
Tau. S pomočjo RNA interference smo in vivo identificirali nov gen, kisodeluje v odzivu
nevronov na toksično delovanje proteina Tau v D. melanogaster: D-Reep1, homolog
človeškega REEP1 gena (h-Reep1). Živali z izbitim D-Reep1 genom niso kazale očitnega
fenotipa v fizioloških pogojih. Spremembe so se pokazale šele ob izpostavitvi stresnim
dejavnikom. Opazili smo tudi, da odsotnost gena D-Reep1 pospeši nevrodegeneracijo, ki jo
povzroči protein Tau v očeh D. melanogaster. Ob izražanju UAS-D-Reep1 in UAS-h-Reep1
kljub toksičnemu delovanju proteina Tau nismo opazili spremenjenega fenotipa na očesu.
Ob podrobnejši analizi sicer nismo ugotovili sprememb fosforilacije D-Reep1, protein pa je
preprečil nastanek Tau agregatov in vivo. Pri nadaljnih raziskavah smo ugotovili, da je REEP1
vpleten v uravnavanje odziva na nezvite proteine (UPR) preko PERK-ATF4 kaskade znotraj
endoplazemskega retikuluma (ER). Aktivacija kaskade je povzročila odstranitev
nevrotoksičnih agregatov Tau, živčno tkivo pa ni kazalo patoloških znakov. Rezultati
nakazujejo, da je za odstranitev agregatov Tau odgovorna autofagija, kar nam podaja nove
informacije o fiziološki vlogi D-Reep1 v živčnem sistemu.
AD Alzheimer Disease APP Amyloid precursor protein CNS Central Nervous System DM Drosophila melanogaster HSP Hereditary Spastic Paraplegia LN Lewy’s neurite MT Microtubule MAP Microtubule associated protein MT Microtubule/s MTBD Microtubule binding domain NFT Neurofibrillary tangle NP Neuritic plaques PHF Paired helical filament PS1 Presenilin 1 PS2 Presenilin 2 SPG Spastic Paraplegia ThS Thioflavin S
AD Alzheimer Disease APP Amyloid precursor protein CNS Central Nervous System DM Drosophila melanogaster HSP Hereditary Spastic Paraplegia LN Lewy’s neurite MT Microtubule MAP Microtubule associated protein MT Microtubule/s MTBD Microtubule binding domain NFT Neurofibrillary tangle NP Neuritic plaques PHF Paired helical filament PS1 Presenilin 1 PS2 Presenilin 2 SPG Spastic Paraplegia ThS Thioflavin S
true
true
false
Angleški jezik
Slovenski jezik
Doktorsko delo/naloga
2019-10-09 10:06:49
2019-12-06 02:18:08
2023-06-09 03:34:48
0000-00-00 00:00:00
2019
0
Nova Gorica
0
0000-00-00
NiDoloceno
NiDoloceno
NiDoloceno
0000-00-00
0000-00-00
0000-00-00
5498619
URN:SI:UNG:REP:XR9BPBFH
Alessio_Guglielmi.pdf
Alessio_Guglielmi.pdf
1
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64081e6f-05cf-11ee-9c48-5ef991fed68f
https://repozitorij.ung.si/Dokument.php?lang=slv&id=18730
Fakulteta za podiplomski študij
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