LSEC: a microenvironment dependent differentiation program in rat including the novel junctional protein Leda-1

ABSTRACT: Liver sinusoidal endothelium (LSEC) is a prime example for organ-specific microvascular differentiation and functions. Disease-associated capillarization of LSEC in vivo and dedifferentiation of LSEC in vitro indicate the importance of the hepatic microenvironment. To identify the LSEC-specific molecular differentiation program in the rat, we used a two-sided gene expression profiling approach comparing LSEC freshly isolated ex vivo with both lung microvascular endothelial cells (LMEC) and with LSEC cultured for 42h. The LSEC signature consisted of 48 genes both down-regulated in LMEC and in LSEC upon culture (FC>7 in at least one comparison); qRT-PCR confirmation of these genes included numerous family members and signalling pathway-associated molecules. The LSEC differentiation program comprised distinct sets of growth (wnt2, Fzd4, 5, 9, wls, VEGFR1, 2, 3, Nrp2) and transcription factors (Gata4, Lmo3, Tcfec, Maf) as well as endocytosis-related (Stabilin-1/2, Lyve1 and Ehd3) and cytoskeleton-associated molecules (Rnd3/RhoE). Specific gene induction in cultured LSEC versus freshly isolated LSEC as well as LMEC (Esm-1, Aatf) and up-regulation of gene expression to LMEC levels (CXCR4, Apelin) confirmed true transdifferentiation of LSEC in vitro. In addition, our analysis identified a novel 26 kDa single-pass transmembrane protein, liver endothelial differentiation-associated protein (Leda)-1, that was selectively expressed in all liver endothelial cells and preferentially localized to the abluminal cell surface. Upon forced over-expression in MDCK cells, Leda-1 was sorted baso-laterally to E-cadherin-positive adherens junctions suggesting functional involvement in cell adhesion and polarity. Conclusion: Comparative microvascular analysis in rat identified a hepatic microenvironment-dependent LSEC-specific differentiation program including the novel junctional molecule Leda-1. Highly pure liver sinusoidal endothelial cells (LSEC) and lung microvascular endothelial cells (LMEC) were isolated by enzymatic digestion, density gradient centrifugation and MACS sorting and subjected to RNA extraction and affymetrix hybridization without any culturing step (LSEC_0h, LMEC_0h). LSEC were also plated on collagen coated dishes and RNA extraction and Affymetrix hybridization was carried out after 2h and 42h in culture (LSEC_2h, LSEC_42h).

ORGANISM(S): Rattus norvegicus

SUBMITTER: Kai Schledzewski 

PROVIDER: E-GEOD-20375 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress