Receptor protein tyrosine phosphatase mu expression as a marker for endothelial cell heterogeneity; analysis of RPTPmu gene expression using LacZ knock-in mice (original) (raw)
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Experimental Cell Research, 1999
We investigated the localization of receptor-type protein-tyrosine phosphatase (RPTP) in tissues by immunofluorescence. RPTP immunoreactivity was found almost exclusively within vascular endothelial cells. RPTP was more abundant in the arterial tree than in the venous circulation. This pattern of expression was opposite to that of the von Willebrand factor and demonstrated a lack of difference in expression of VE-cadherin. RPTP was undetectable in the endocardium. In agreement with previous work on nonendothelial cell lines, RPTP was exclusively at the lateral aspects of endothelial cells in vivo and at cell-cell contacts as well as ex vivo in two-or three-dimensional endothelial cell cultures, and expression levels were upregulated by cell density. RPTP was detected in few other cells: bronchial and biliary epithelia and cardiocytes (intercalated discs). Our results identify RPTP as a new marker of endothelial cell heterogeneity and suggest a possible role in endothelial-specific functions, involving cell-cell contact.
The American Journal of Pathology, 2005
The pulmonary vascular endothelial paracellular pathway and zonula adherens (ZA) integrity are regulated, in part, through protein tyrosine phosphorylation. ZA-associated protein tyrosine phosphatase (PTP)s are thought to counterregulate tyrosine phosphorylation events within the ZA multiprotein complex. One such receptor PTP, PTP, is highly expressed in lung tissue and is almost exclusively restricted to the endothelium. We therefore studied whether PTP, in pulmonary vascular endothelia, associates with and/or regulates both the tyrosine phosphorylation state of vascular endothelial (VE)cadherin and the paracellular pathway. PTP was expressed in postconfluent human pulmonary artery and lung microvascular endothelial cells (ECs) where it was almost exclusively restricted to EC-EC boundaries. In human lung microvascular ECs, knockdown of PTP through RNA interference dramatically impaired barrier function. In immortalized human microvascular ECs, overexpression of wild-type PTP enhanced barrier function. PTP-VE-cadherin interactions were demonstrated through reciprocal co-immunoprecipitation assays and co-localization with double-label fluorescence microscopy. When glutathione S-transferase-PTP was incubated with purified recombinant VE-cadherin, and when glutathione Stransferase-VE-cadherin was incubated with purified recombinant PTP, PTP directly bound to VE-cadherin. Overexpression of wild-type PTP decreased tyrosine phosphorylation of VE-cadherin. Therefore, PTP is expressed in human pulmonary vascular endothelia where it directly binds to VE-cadherin and regulates both the tyrosine phosphorylation state of VE-cadherin and barrier integrity.
Expression of receptor-type protein tyrosine phosphatase in developing and adult renal vasculature
PloS one, 2017
Renal vascular development is a coordinated process that requires ordered endothelial cell proliferation, migration, intercellular adhesion, and morphogenesis. In recent decades, studies have defined the pivotal role of endothelial receptor tyrosine kinases (RPTKs) in the development and maintenance of renal vasculature. However, the expression and the role of receptor tyrosine phosphatases (RPTPs) in renal endothelium are poorly understood, though coupled and counterbalancing roles of RPTKs and RPTPs are well defined in other systems. In this study, we evaluated the promoter activity and immunolocalization of two endothelial RPTPs, VE-PTP and PTPμ, in developing and adult renal vasculature using the heterozygous LacZ knock-in mice and specific antibodies. In adult kidneys, both VE-PTP and PTPμ were expressed in the endothelium of arterial, glomerular, and medullary vessels, while their expression was highly limited in peritubular capillaries and venous endothelium. VE-PTP and PTPμ ...
Mechanisms of Development
Using RNA in situ hybridization we compared the expression patterns of the cell adhesion molecule-like receptor-type protein tyrosine phosphatases LAR, RPTP sigma and RPTP sigma during mouse development. We found that LAR is expressed in basal lamina-associated epithelial tissues of (neuro)ectodermal, neural crest/ectomesenchyme and endodermal origin. RPTP sigma is found in (neuro)ectodermal, neural crest-derived systems and in mesoderm-derived tissues. The expression pattern of RPTP sigma largely parallels that of RPTP sigma, in concordance with their proposed evolutionary history
Mechanisms of Development, 1998
Using RNA in situ hybridization we compared the expression patterns of the cell adhesion molecule-like receptor-type protein tyrosine phosphatases LAR, RPTPd and RPTPj during mouse development. We found that LAR is expressed in basal lamina-associated epithelial tissues of (neuro)ectodermal, neural crest/ectomesenchyme and endodermal origin. RPTPj is found in (neuro)ectodermal, neural crestderived systems and in mesoderm-derived tissues. The expression pattern of RPTPj largely parallels that of RPTPj, in concordance with their proposed evolutionary history .
Proceedings of the National Academy of Sciences, 1997
TIE2 is a vascular endothelial-specific receptor tyrosine kinase essential for the regulation of vascular network formation and remodeling. Previously, we have shown that the 1.2-kb 5 flanking region of the TIE2 promoter is capable of directing -galactosidase reporter gene expression specifically into a subset of endothelial cells (ECs) of transgenic mouse embryos. However, transgene activity was restricted to early embryonic stages and not detectable in adult mice. Herein we describe the identification and characterization of an autonomous endothelial-specific enhancer in the first intron of the mouse TIE2 gene. Furthermore, combination of the TIE2 promoter with an intron fragment containing this enhancer allows it to target reporter gene expression specifically and uniformly to virtually all vascular ECs throughout embryogenesis and adulthood. To our knowledge, this is the first time that an in vivo expression system has been assembled by which heterologous genes can be targeted exclusively to the ECs of the entire vasculature. This should be a valuable tool to address the function of genes during physiological and pathological processes of vascular ECs in vivo. Furthermore, we were able to identify a short region critical for enhancer function in vivo that contains putative binding sites for Ets-like transcription factors. This should, therefore, allow us to determine the molecular mechanisms underlying the vascular-EC-specific expression of the TIE2 gene.
A Mutant Receptor Tyrosine Phosphatase, CD148, Causes Defects in Vascular Development
Molecular and Cellular Biology, 2003
Vascularization defects in genetic recombinant mice have defined critical roles for a number of specific receptor tyrosine kinases. Here we evaluated whether an endothelium-expressed receptor tyrosine phosphatase, CD148 (DEP-1/PTP), participates in developmental vascularization. A mutant allele, CD148 ⌬CyGFP , was constructed to eliminate CD148 phosphatase activity by in-frame replacement of cytoplasmic sequences with enhanced green fluorescent protein sequences. Homozygous mutant mice died at midgestation, before embryonic day 11.5 (E11.5), with vascularization failure marked by growth retardation and disorganized vascular structures. Structural abnormalities were observed as early as E8.25 in the yolk sac, prior to the appearance of intraembryonic defects. Homozygous mutant mice displayed enlarged vessels comprised of endothelial cells expressing markers of early differentiation, including VEGFR2 (Flk1), Tal1/SCL, CD31, ephrin-B2, and Tie2, with notable lack of endoglin expression. Increased endothelial cell numbers and mitotic activity indices were demonstrated. At E9.5, homozygous mutant embryos showed homogeneously enlarged primitive vessels defective in vascular remodeling and branching, with impaired pericyte investment adjacent to endothelial structures, in similarity to endoglin-deficient embryos. Developing cardiac tissues showed expanded endocardial projections accompanied by defective endocardial cushion formation. These findings implicate a member of the receptor tyrosine phosphatase family, CD148, in developmental vascular organization and provide evidence that it regulates endothelial proliferation and endothelium-pericyte interactions.
Cell, 1999
In addition, VEGF is a potent inducer of vascular perme-Farmington, Connecticut 06030-3501 ability, a prerequisite initial event for plasma exudation and fibrin clot formation, a matrix permissive for angiogenesis (Iruela-Arispe and Dvorak, 1997). However, fac-Summary tors and mechanisms that regulate morphogenesis of endothelial cells into capillary-like networks are poorly Vascular endothelial cells undergo morphogenesis understood. into capillary networks in response to angiogenic fac-
Endothelial signaling during development
Nature Medicine, 2003
The 'active' endothelium The endothelium of blood vessels has traditionally been regarded as rather inert 'plumbing' , which enables metabolic exchange between blood and tissues by virtue of its permeability and proximity to all cells. In recent decades, however, there has been a reassessment of the role of the endothelium, suggesting that it is "more than a sheet of nucleated cellophane" 1 . Endothelial signals are now implicated in the regulation of many processes, and endothelial cells (ECs) are known to communicate directly with adjacent cells.