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Glutaminase Stimulates the Proliferation of Human Endothelial Cells
Author(s) -
Durante William,
Liu Xiaoming,
Yates Benjamin,
Yu Yajie,
Peyton Kelly J.
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.957.3
Subject(s) - glutaminase , umbilical vein , cell growth , cell cycle , flow cytometry , microbiology and biotechnology , endothelial stem cell , cell culture , glutamine , human umbilical vein endothelial cell , biology , cyclin , chemistry , cell , biochemistry , in vitro , genetics , amino acid
Glutaminase (GLS) is a mitochondrial enzyme that metabolizes glutamine to glutamate and ammonia. Two distinct isoforms of GLS, GLS1 and GLS2, have been identified in mammals that exhibit distinct tissue distribution, enzyme kinetics, structural properties and molecular regulation. Although abundant GLS activity has been reported in endothelial cells, its functional role remains largely unknown. In the present study, we characterized the expression of GLS in endothelial cells and investigated the effect of GLS on the proliferation of endothelial cells. Human umbilical vein endothelial cells (HUVEC) expressed high levels of GLS1, but GLS2 was not detected in these cells. Treatment of HUVEC with the non‐selective GLS inhibitor 6‐diazo‐5‐oxo‐L‐ornithine (DON) or the selective GLS1 inhibitor bis‐2‐(5‐phenylacetamido‐1,3,4‐thiadiazol‐2‐yl)ethyl sulfide (BPTES) resulted in a concentration‐dependent inhibition of endothelial cell growth. Both GLS inhibitors also blocked HUVEC DNA synthesis and this was paralleled by a significant decrease in the phosphorylation of retinoblastoma protein. In addition, knockdown of GLS1 expression using a siRNA approach inhibited the mitogenic response of HUVEC. Flow cytometry experiments revealed that DON or BPTES arrested HUVEC in the G 0 /G 1 phase of the cell cycle, as demonstrated by an increase in the percentage of cells in G 0 /G 1 with a corresponding decline in the portion of cells in S and G 2 /M phases. Cell cycle arrest by the GLS inhibitors was associated with a dramatic reduction in cyclin A expression without any change in the expression of the other G1 cyclins, cyclin D1 and E, the cyclin‐dependent kinase inhibitors, p21 or p27, or p53. In conclusion, this study demonstrates that endothelial cells selectively express GLS1, and that GLS1 plays a fundamental role in stimulating human endothelial cell cyclin A expression, cell cycle progression, and proliferation. Support or Funding Information Supported by American Heart Association Grants 15GRNT25250015.