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postgraduate thesis: Activation of NRG1-ERBB4 signaling potentiates mesenchymal stem cell-mediated myocardial repairs

TitleActivation of NRG1-ERBB4 signaling potentiates mesenchymal stem cell-mediated myocardial repairs
Authors
Issue Date2015
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Liang, X. [梁小婷]. (2015). Activation of NRG1-ERBB4 signaling potentiates mesenchymal stem cell-mediated myocardial repairs. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5387983
AbstractMesenchymal stem cell (MSC) transplantation has achieved only modest success in the treatment of ischemic heart disease due to poor cell viability in the diseased microenvironment. Genetic manipulation on the MSCs holds promising prospects in enhancing cell tolerance against adverse environmental conditions. Recent studies demonstrate that the activation of the NRG1 (neuregulin 1) - ERBB4 (v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4) pathway can enhance pro-survival signaling, stimulate mature cardiomyocyte cell cycle re-entry and cell division. In this study, I aimed to determine whether activating NRG1-ERBB4 in MSCs can enhance their cardioprotective effects following myocardial infarction. In chapter 3, I determined that MSC endogenously expresses NRG1, but not ERBB4. Considering the absence of ERBB4 in the MSCs might lead to mute response to its ligand NRG1, I exogenously manipulated ERBB4 into MSCs. In chapter 4, MSCs, with or without ERBB4 overexpression were transplanted into mice following myocardial infarction. The transplantation of MSCs with ERBB4 expression considerably improved left ventricular ejection fraction and reduced infarctsize, compared to unmodified MSCs and direct NRG1 injection. ERBB4 overexpression induced greater MSC survival following infarction. The transduction of ERBB4 in MSCs increased cell mobility and apoptotic resistance via a PI3K/Akt pathway under hypoxic conditions in the presence of NRG1. The transplantation of MSCs with ERBB4 expression induced cardiomyocyte division and protected them against apoptosis during early phase of infarction. In chapter 5, a novel autocrine loop regarding to NRG1-ERBB4-NRG1 signaling was identified. MSCs with ERBB4 overexpression in turn increased NRG1 synthesis and secretion. Conditioned medium of ERBB4-expressing MSCs containing elevated NRG1, promoted cardiomyocyte growth, division and anti-senescence, whereas neutralization of NRG1 blunted these effects. Injecting ERBB4-expressing MSCs restored NRG1 in the infarcted myocardium to a level comparable with that of the normal myocardium. These findings collectively suggest overexpressing ERBB4 in MSCs enhances the effectiveness of MSCtherapy following myocardial in farction through potentiating MSC survival and revitalizing endogenous repair and regeneration. The combination of ERBB4 and MSC is more efficient than naïve MSC or solely recombinant NRG1 injection, emerging as potential target for developing novel strategy in treating myocardial diseases.
DegreeDoctor of Philosophy
SubjectMyocardium - Regeneration
Mesenchymal stem cells
Dept/ProgramMedicine
Persistent Identifierhttp://hdl.handle.net/10722/208584

 

DC FieldValueLanguage
dc.contributor.authorLiang, Xiaoting-
dc.contributor.author梁小婷-
dc.date.accessioned2015-03-13T01:44:02Z-
dc.date.available2015-03-13T01:44:02Z-
dc.date.issued2015-
dc.identifier.citationLiang, X. [梁小婷]. (2015). Activation of NRG1-ERBB4 signaling potentiates mesenchymal stem cell-mediated myocardial repairs. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5387983-
dc.identifier.urihttp://hdl.handle.net/10722/208584-
dc.description.abstractMesenchymal stem cell (MSC) transplantation has achieved only modest success in the treatment of ischemic heart disease due to poor cell viability in the diseased microenvironment. Genetic manipulation on the MSCs holds promising prospects in enhancing cell tolerance against adverse environmental conditions. Recent studies demonstrate that the activation of the NRG1 (neuregulin 1) - ERBB4 (v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4) pathway can enhance pro-survival signaling, stimulate mature cardiomyocyte cell cycle re-entry and cell division. In this study, I aimed to determine whether activating NRG1-ERBB4 in MSCs can enhance their cardioprotective effects following myocardial infarction. In chapter 3, I determined that MSC endogenously expresses NRG1, but not ERBB4. Considering the absence of ERBB4 in the MSCs might lead to mute response to its ligand NRG1, I exogenously manipulated ERBB4 into MSCs. In chapter 4, MSCs, with or without ERBB4 overexpression were transplanted into mice following myocardial infarction. The transplantation of MSCs with ERBB4 expression considerably improved left ventricular ejection fraction and reduced infarctsize, compared to unmodified MSCs and direct NRG1 injection. ERBB4 overexpression induced greater MSC survival following infarction. The transduction of ERBB4 in MSCs increased cell mobility and apoptotic resistance via a PI3K/Akt pathway under hypoxic conditions in the presence of NRG1. The transplantation of MSCs with ERBB4 expression induced cardiomyocyte division and protected them against apoptosis during early phase of infarction. In chapter 5, a novel autocrine loop regarding to NRG1-ERBB4-NRG1 signaling was identified. MSCs with ERBB4 overexpression in turn increased NRG1 synthesis and secretion. Conditioned medium of ERBB4-expressing MSCs containing elevated NRG1, promoted cardiomyocyte growth, division and anti-senescence, whereas neutralization of NRG1 blunted these effects. Injecting ERBB4-expressing MSCs restored NRG1 in the infarcted myocardium to a level comparable with that of the normal myocardium. These findings collectively suggest overexpressing ERBB4 in MSCs enhances the effectiveness of MSCtherapy following myocardial in farction through potentiating MSC survival and revitalizing endogenous repair and regeneration. The combination of ERBB4 and MSC is more efficient than naïve MSC or solely recombinant NRG1 injection, emerging as potential target for developing novel strategy in treating myocardial diseases.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.subject.lcshMyocardium - Regeneration-
dc.subject.lcshMesenchymal stem cells-
dc.titleActivation of NRG1-ERBB4 signaling potentiates mesenchymal stem cell-mediated myocardial repairs-
dc.typePG_Thesis-
dc.identifier.hkulb5387983-
dc.description.thesisnameDoctor of Philosophy-
dc.description.thesislevelDoctoral-
dc.description.thesisdisciplineMedicine-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b5387983-

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