European Foundation for the Study of Diabetes - EFSD/Lilly Research Fellowship Programme - In situ analysis of hepatic stellate cell signaling in the development of hepatic fibrosis

Project: Research

Project Details


Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. Affecting 20-30% of the population, NAFLD is now the most common liver disease in the Western world. Yet, the lack of knowledge about signaling pathways promoting disease progression in vivo limits our ability to develop strategies for rational, therapeutic intervention.

To meet this challenge, we developed our creTRAP platform for cell type-specific transcriptomic profiling and gene knockdown in vivo. CreTRAP involves cre-dependent expression and ribosomal incorporation of the mCherry-tagged ribosomal subunit RPL10A in selected cell types. Ribosomal mCherry-RPL10A allows for cell type-specific isolation of polysomes with associated mRNA from whole liver lysates followed by RNA sequencing.

Advanced NAFLD is characterized by activation and proliferation of hepatic stellate cells (HSCs). Activated HSCs are the main source of collagen-secreting myofibroblasts and are instrumental for hepatic fibrosis. Transcriptomic analysis of in vitro-activated HSCs led us to identify TEAD-binding motifs in promoters of induced genes. The TEAD transcription factors and their co-activators Yap1 and Wwtr1 integrate signals from the Hippo pathway and other pathways that sense the cellular microenvironment. As transcriptional effectors of these pathways Yap1/Wwtr1 stimulate cellular proliferation and migration. Indeed, immunohistochemical (IHC) analyses confirm highly increased Yap1 protein levels in the vicinity of fibrotic lesions.

By employing the creTRAP platform for HSC-specific transcriptomic analysis and in vivo knockdown we will further explore Yap1/Wwtr1 and their role in HSC activation and development of NAFLD. Through targeted modulation of regulatory pathways in HSCs, we seek to discover novel intra- and intercellular mechanisms linking metabolic stress and hepatic inflammation to Yap1/Wwtr1 activation and chronic liver disease in mouse models of diet-induced NAFLD.
Effective start/end date01/07/201531/12/2017