Uloga signalnog puta Notch u jetrenim zvjezdolikim stanicama tijekom razvoja mišjeg modela jetrene fibroze

doctoral thesis

• Title (english): The role of Notch signaling pathway in hepatic stellate cells in development of murine model of liver fibrosis
• Author: Dino Šisl
• Mentor: Tomislav Kelava (mentor)
• Committee member: Danka Grčević (predsjednik povjerenstva)
• Committee member: Drago Batinić (član povjerenstva)
• Committee member: Nataša Kovačić (član povjerenstva)
• Granter: University of Zagreb; School of Medicine; Zagreb
• Defense date and country: 2022-12-15, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Clinical Medical Sciences; Clinical Immunology
• Universal decimal classification (UDC): 612 - Physiology

Abstract

U ovom radu istražili smo kako modulacija signalnog puta Notch u aktiviranim jetrenim
zvjezdolikim stanicama (aHSC) utječe na razvoj fibroze koristeći dva životinjska modela,
toksični model primjene CCl4 i kolestatski model prehrane s dodatkom spoja DDC. Pokazali
smo da je signalni put Notch induciran tijekom razvoja fibroze. Zatim smo na transgeničnim
miševima soja SMACreERT2+/-/Ai9 pokazali da se stanice koje bazalno izražavaju αSMA ne
umnožavaju tijekom fibroze te da su glavni izvor miofibroblasta HSC. Pokusima na miševima
soja SMACreERT2+/-/RBP-Jfl/fl i SMACreERT2+/-/RosaNICD1 pokazali smo da inhibicija ili
pojačana aktivacija signalnog puta Notch u aHSC ne utječe na stupanj fibroze. Nadalje,
pokazali smo da u miševa s pojačanom aktivnošću signalnog puta Notch dolazi do normalnog
oporavka od fibroze po prestanku fibrogenog poticaja. U nedavno objavljenom sličnom
istraživanju pokazano je da inhibicija signalnog puta Notch smanjuje razvoj fibroze, ali ono
nije procijenilo mogućnost antifibrotičkog učinka samog tamoksifena. Stoga smo u završnoj
fazi istraživanja istražili može li tamoksifen imati utjecaja na ishod fibroze jetre u kolestatskom
modelu. Pokazali smo da tamoksifen ima antifibrotični učinak u kolestatskom modelu, a naša
hipoteza je da je zaštitni učinak tamoksifena posredovan pojačanim izražavanjem Tgfβ i Il6 te
smatramo da bi ovi signalni putevi trebali biti fokus daljnjih istraživanja.

Abstract (english)

We aimed to investigate how Notch signaling pathway modulation (inhibition and
overactivation) affects the development of liver fibrosis. In the first experiment we have shown
that Notch signaling pathway is induced in two fibrosis models, CCl4 application and DDCsupplemented
feeding. Further, by using transgenic SMACreERT2+/-/Ai9 mice, we have shown
that constitutionally αSMA-positive cells do not multiply during fibrosis and that the main
source of αSMA-positive myofibroblasts must be hepatic stellate cells. By using
SMACreERT2+/-/RBP-Jfl/fl and SMACreERT2+/-/RosaNICD1 mice we have shown that neither
Notch inhibition nor its overactivation in activated hepatic stellate cells affects the degree of
liver fibrosis. Furthermore, Notch overactivation had no effect on resolution of liver fibrosis
once the fibrogenic stimulus was removed. A recently published article with a methodology
similar to ours reported a lesser extent of fibrosis with Notch inhibition, but the possibility of
confounding effect of tamoxifen remained open. Therefore, we decided to investigate whether
tamoxifen itself affects fibrosis development in the DDC-model. Our results show that
tamoxifen indeed has a protective role in the DDC-model and we hypothesize that the
protective effect of tamoxifen might be mediated through Il6 and Tgfβ upregulation, suggesting
these pathways as a primary focus for further research.

• Keywords: Miofibroblasti; Povećanje regulacije; Miševi; transgeni; Tamoksifen; Ciroza jetre; Fibroza
• Keywords (english): Myofibroblasts; Mice; Transgenic; Tamoxifen; Liver Cirrhosis; Fibrosis
• Language: croatian
• URN:NBN: urn:nbn:hr:105:172397
• Project: Number: UIP-2017-05-1965; Title: Uloga Notch signalnog puta u patogenezi jetrene fibroze; Acronym: NOFIBRO; Leader: Tomislav Kelava; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: UIP
• Study programme: Title: Biomedicine and Health Sciences; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje biomedicine i zdravstvo (doktor/doktorica znanosti, područje biomedicine i zdravstvo)
• Type of resource: Text
• Extent: 92 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-01-12 08:32:24