The role of WNK in modulation of KCl cotransport activity in red cells from normal individuals and patients with sickle cell anaemia

David C.Y. Lu, Anke Hannemann, Rasiqh Wadud, David C. Rees, John N. Brewin, Philip S. Low, John S. Gibson

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Abnormal activity of red cell KCl cotransport (KCC) is involved in pathogenesis of sickle cell anaemia (SCA). KCC-mediated solute loss causes shrinkage, concentrates HbS, and promotes HbS polymerisation. Red cell KCC also responds to various stimuli including pH, volume, urea, and oxygen tension, and regulation involves protein phosphorylation. The main aim of this study was to investigate the role of the WNK/SPAK/OSR1 pathway in sickle cells. The pan WNK inhibitor WNK463 stimulated KCC with an EC50 of 10.9 ± 1.1 nM and 7.9 ± 1.2 nM in sickle and normal red cells, respectively. SPAK/OSR1 inhibitors had little effect. The action of WNK463 was not additive with other kinase inhibitors (staurosporine and N-ethylmaleimide). Its effects were largely abrogated by pre-treatment with the phosphatase inhibitor calyculin A. WNK463 also reduced the effects of physiological KCC stimuli (pH, volume, urea) and abolished any response of KCC to changes in oxygen tension. Finally, although protein kinases have been implicated in regulation of phosphatidylserine exposure, WNK463 had no effect. Findings indicate a predominant role for WNKs in control of KCC in sickle cells but an apparent absence of downstream involvement of SPAK/OSR1. A more complete understanding of the mechanisms will inform pathogenesis whilst manipulation of WNK activity represents a potential therapeutic approach.

Original languageEnglish (US)
Pages (from-to)1539-1549
Number of pages11
JournalPflugers Archiv European Journal of Physiology
Volume471
Issue number11-12
DOIs
StatePublished - Dec 1 2019

Keywords

  • KCl cotransport
  • Phosphorylation
  • SPAK/OSR1
  • Sickle cells
  • WNK

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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