title: Influence of protein histidine phosphatase overexpression and down-regulation on human umbilical-vein endothelial cell viability.
abstract: PHP (protein histidine phosphatase) is expressed by mammalian tissues, particularly in blood vessel walls. We investigated whether PHP plays a significant role in endothelial cells. By Western blot and immunofluorescence analysis PHP was found in HUVEC (human umbilical-vein endothelial cells). Overexpression of PHP by the use of a plasmid vector, pIRES2-AcGFP1-PHP, induced apoptosis in HUVEC. To exclude the possibility that increased cellular protein alone unspecifically caused cell damage, the inactive H53A mutant of PHP was also overexpressed as a control; it did not lead to apoptosis. Down-regulation of PHP by the RNAi (RNA interference) technique did not affect cell viability. In conclusion, HUVEC are damaged by overexpression, but not down-regulation, of PHP, suggesting a pronounced impact of the enzyme on the cells when its activity is increased.
authors.affiliation: Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Pharmazeutische und Medizinische Chemie, Muenster, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Seeger
authors.forename: Karsten
authors.initials: K
authors.lastname: Rose
authors.forename: Nien Tze
authors.initials: NT
authors.lastname: Ma
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.forename: Susanne
authors.initials: S
authors.lastname: Klumpp
authors.forename: Josef
authors.initials: J
authors.lastname: Krieglstein
mesh_terms: D000818:Animals; D017209:Apoptosis; D002470:Cell Survival / Q000235:genetics; D015536:Down-Regulation; D005455:Fluorescent Antibody Technique; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism*; D006801:Humans; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats
chemical_list: D034741:RNA, Small Interfering; C504019:PHPT1 protein, human; D010744:Phosphoric Monoester Hydrolases