Biology subjects

Rempel, E.

Publications and source records attributed to Rempel, E..

3 recordsLinked to original sources

bioRxiv2020

YAP orchestrates heterotypic endothelial cell communication via HGF/c-MET signaling in liver tumorigenesis

Next to cell autonomous mechanisms, the oncogene yes-associated protein (YAP) controls liver tumor initiation and progression via cell extrinsic functions creating a tumor-supporting environment. However, how YAP affects the microenvironment and in particular the vascular niche, which contributes to liver disease and hepatocarcinogenesis, is poorly understood. In this study, histo-morphological and molecular characterization of murine liver endothelial cells (ECs) populations and human single cell data revealed the presence of liver sinusoidal endothelial cells (LSECs) and capillary endothelial cells (CECs) in healthy liver tissue. In YAPS127A-induced tumorigenesis, a gradual replacement of LSECs by CECs was associated with dynamic changes in the expression of genes involved in EC subtype-specific paracrine communication. The formation of new potential communication hubs connecting CECs and LSECs included the hepatocyte growth factor (Hgf)/c-Met signaling pathway. In hepatocytes and tumor cells, YAP/TEA domain transcription factor 4 (TEAD4)-dependent transcriptional induction of osteopontin (Opn) stimulated c-Met expression in ECs with CEC phenotype, which sensitized these cells to the pro-migratory effects of LSEC-derived Hgf. In human HCCs, the presence of a migration-associated tip-cell signature correlated with poor clinical outcome and the loss of LSEC marker gene expression. In addition, the replacement of LSECs by CECs with exclusive c-MET expression in a CEC subpopulation was confirmed at the single cell level. In summary, YAP-dependent changes of the liver vascular niche comprise the formation of heterologous communication hubs (e.g. the HGF/c-Met axis), in which tumor cell-derived factors modify the crosstalk between LSECs and CECs.

cancer biology↗

bioRxiv2018

WEADE: a workflow for enrichment analysis and data exploration

Data analysis based on enrichment of Gene Ontology terms has become an important step in exploring large gene or protein expression datasets and several stand-alone or web tools exist for that purpose. However, a comprehensive and consistent analysis downstream of the enrichment calculation is missing so far. With WEADE we present a free web application that offers an integrated workflow for the exploration of genomic data combining enrichment analysis with a versatile set of tools to directly compare and intersect experiments or candidate gene lists of any size or origin including cross-species data. Lastly, WEADE supports the graphical representation of output data in the form of functional interaction networks based on prior knowledge, allowing users to go from plain expression data to functionally relevant candidate sub-lists in an interactive and consistent manner.

bioinformatics↗

bioRxiv2017

Decoding the regulatory logic of the Drosophila male stem cell system

In the past decade, the importance of the niche to provide regulatory inputs to balance stem cell self-renewal and differentiation has become clear. However, the regulatory interplay between stem cells and their niche at the whole genome level is still poorly understood. To elucidate the mechanisms controlling stem cells and their progenies as they progress through their developmental program at the transcriptional level, we recorded the regulatory program of two independent cell lineages in the Drosophila testis stem cell model. To this end, we identified genes active in the soma or germline as well as genome-wide binding profiles of two essential transcription factors, Zfh-1 and Abd-A, expressed in somatic support cells and crucial for fate acquisition of both cell lineages. Our data identified key roles for TOR signalling, signal processing V-ATPase proton pumps and the nuclear transport engaged nucleoporins and we demonstrate their importance in controlling germline maintenance, proliferation and differentiation from the support side. To make our dataset publicly available and support quick and intuitive data mining, we generated an interactive online analysis tool. Applying our tool for comparative analysis, we uncovered conserved core gene sets of adult stem cells across species boundaries. We have tested the functional relevance of these genes in the Drosophila testis and intestine and find a striking overrepresentation of stem cell defects when the corresponding genes were depleted. In summary, our dataset and interactive platform represents a versatile tool for identifying novel gene networks active in diverse stem cell types and provides a valuable resource for elucidating the multifaceted regulatory inputs required to guide proper stem cell behaviour.

developmental biology↗