Angiogenic growth factors augment K-Cl cotransporter expression in erythroid cells via hypoxia-inducible factor-1α

• Type of Material: Article
• Authors: Caryn S Gonsalves, Children's Hospital Medical Center; Scott Crable, Children's Hospital Medical Center; Sharat Chandra, Children's Hospital Medical Center; Wei Li, Emory University; Vijay K Kalra, University of Southern California; Clinton Joiner, Emory University
• Language: English
• Date: 2014-03
• Publisher: Wiley: 12 months
• Publication Version: Final Published Version
• Copyright Statement: © 2013 Wiley Periodicals, Inc.
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1002/ajh.23631
• Title of Journal or Parent Work: American Journal of Hematology
• ISSN: 0361-8609
• Volume: 89
• Issue: 3
• Start Page: 273
• End Page: 281
• Grant/Funding Information: NIH; Contract grant number: U54 HL070871 (to CHJ).
• Keywords: MAP Kinase Signaling System; Animals; Vascular Endothelial Growth Factor Receptor-1; RNA, Neoplasm; Transcription, Genetic; Gene Expression Regulation, Leukemic; Cell Hypoxia; Vascular Endothelial Growth Factor A; Genes, Reporter; Humans; Pregnancy Proteins; Symporters; RNA, Small Interfering; Protein Kinase Inhibitors; Transduction, Genetic; Mice; Neoplasm Proteins; K562 Cells; Hypoxia-Inducible Factor 1, alpha Subunit; Mice, Inbred C57BL; RNA, Messenger; RNA Interference
• Research Categories: Health Sciences, General; Health Sciences, Oncology

Abstract

The potassium chloride cotransporters (KCC) family of proteins are widely expressed and are involved in the transepithelial movement of potassium and chloride ions and the regulation of cell volume. KCC activity is high in reticulocytes, and contributes to the dehydration of sickle red blood cells. Because plasma levels of both vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) are elevated in sickle cell individuals, and VEGF has been shown to increase KCC expression in other cells, we hypothesized that VEGF and PlGF influence KCC expression in erythroid cells. Both VEGF and PlGF treatment of human erythroid K562 cells increased both mRNA and protein levels of KCC1, KCC3b, and KCC4. VEGF- and PlGF-mediated cellular signaling involved VEGF-R1 and downstream effectors, specifically, PI-3 kinase, p38 MAP kinase, mTOR, NADPH-oxidase, JNK kinase, and HIF-1α. VEGF and PlGF-mediated transcription of KCC3b and KCC4 involved hypoxia response element (HRE) motifs in their promoters, as demonstrated by promoter analysis, EMSA and ChiP. These results were corroborated in vivo by adenoviral-mediated overexpression of PlGF in normal mice, which led to increased expression of mKCC3 and mKCC4 in erythroid precursors. Our studies show that VEGF and PlGF regulate transcription of KCC3b and KCC4 in erythroid cells via activation of HIF-1α, independent of hypoxia. These studies provide novel therapeutic targets for regulation of cell volume in RBC precursors, and thus, amelioration of dehydration in RBCs in sickle cell disease. © 2013 Wiley Periodicals, Inc.