Publikationsserver der RWTH Aachen University
Silencing of endoglin in rat hepatic stellate cells by RNA interference identifies endoglin as an important component of the transdifferentiation process
Abstract
dc:descriptionThe main purpose of this doctoral thesis was the functional characterization of endoglin in hepatic stellate cells (HSC). This characterization was performed particularly with regard to the impact and the function of endoglin in the transdifferentiation process of HSC into myofibroblast-like cells (MFB). Transdifferentiation of HSC into MFB plays a crucial role in the wound healing process of the liver and is, thus, linked to the development of fibrosis. Endoglin functions as a TGF-beta receptor and TGF-beta, on the other hand, is a key regulator that initiates and perpetuates the transdifferentiation process. This raises the questions whether endoglin has any impact on the transdifferentiation of HSC and whether endoglin is involved in the process of liver fibrogenesis. To investigate these questions, RNAi was used for the first time in this laboratory in order to silence endoglin. By transfecting HSC with siRNA oligonucleotides endoglin was down-regulated very efficiently. Subsequently, endoglin lacking HSC were analyzed and compared with the control cells providing a first insight into the function of endoglin in HSC. This analysis revealed an inhibition of the transdifferentiation process in HSC lacking endoglin. Inhibition is represented by a decreased amount of ECM components, by alterations in the organization of the cytoskeleton and by a reduced proliferation. Furthermore, a cDNA microarray was performed in order to designate other mediators, which were differentially expressed in HSC lacking endoglin and consequently influencing the phenotype. This array revealed many presumed candidates amongst them genes such as a2-macroglobulin and ALK1. Based on their known functions, these candidates might contribute to the phenotype of the endoglin deficient HSC. Finally, stimulation experiments were performed in order to analyze the impact of endoglin on the TGF-beta and the BMP pathways. TGF-beta1 and BMP-7, which are ligands for endoglin, are important cytokines in the formation and the development of liver fibrosis. Stimulation experiments were performed using TGF-beta1 and BMP-7. Reporter gene assay andWestern blot analysis were used as read out systems. Therefore, this research was crucial to demonstrate the importance of endoglin within the process of HSC transdifferentiation. The knock down of endoglin in HSC interferes with the transdifferentiation process and forces phenotypic alteration. Based on these findings it can be assumed that endoglin has an important function within the process of liver fibrogenesis.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2008
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Vreden, Wanda Nicolette
- Contributors dc:contributor
-
- Peterhänsel, Christoph
Subjects
dc:subject × 15Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- eng