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Blood Cells Mol Dis. 2019 Nov;79:102346. doi: 10.1016/j.bcmd.2019.102346. Epub 2019 Jul 17.

Combined genetic disruption of K-Cl cotransporters and Gardos channel KCNN4 rescues erythrocyte dehydration in the SAD mouse model of sickle cell disease.

Author information

1
Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America; Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA 02115, United States of America.
2
Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America; Department of Medicine, Harvard Medical School, Boston, MA 02115, United States of America; Department of Pathology, Harvard Medical School, Boston, MA 02115, United States of America.
3
Department of Laboratory Medicine, UCSF, San Francisco, CA, United States of America.
4
Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America.
5
Institut de Recherches Cliniques de Montreal, Molecular Genetics and Development, Faculte de Medecine, Universite of Montreal, Montreal, Quebec, Canada.
6
Institute of Physiological Chemistry, Philipps-Universität Marburg, Marburg, Germany.
7
Institute of Human Genetics, Universitatsklinikum Jena, Jena, Germany.
8
Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA 02115, United States of America; Department of Pathology, Harvard Medical School, Boston, MA 02115, United States of America.
9
Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America; Department of Medicine, Harvard Medical School, Boston, MA 02115, United States of America. Electronic address: salper@bidmc.harvard.edu.

Abstract

Excessive red cell dehydration contributes to the pathophysiology of sickle cell disease (SCD). The densest fraction of sickle red cells (with the highest corpuscular hemoglobin concentration) undergoes the most rapid polymerization of deoxy-hemoglobin S, leading to accelerated cell sickling and increased susceptibility to endothelial activation, red cell adhesion, and vaso-occlusion. Increasing red cell volume in order to decrease red cell density can thus serve as an adjunct therapeutic goal in SCD. Regulation of circulating mouse red cell volume and density is mediated largely by the Gardos channel, KCNN4, and the K-Cl cotransporters, KCC3 and KCC1. Whereas inhibition of the Gardos channel in subjects with sickle cell disease increased red cell volume, decreased red cell density, and improved other hematological indices in subjects with SCD, specific KCC inhibitors have not been available for testing. We therefore investigated the effect of genetic inactivation of KCC3 and KCC1 in the SAD mouse model of sickle red cell dehydration, finding decreased red cell density and improved hematological indices. We describe here generation of mice genetically deficient in the three major red cell volume regulatory gene products, KCNN4, KCC3, and KCC1 in C57BL6 non-sickle and SAD sickle backgrounds. We show that combined loss-of-function of all three gene products in SAD mice leads to incrementally increased MCV, decreased CHCM and % hyperchromic cells, decreased red cell density (phthalate method), increased resistance to hypo-osmotic lysis, and increased cell K content. The data show that combined genetic deletion of the Gardos channel and K-Cl cotransporters in a mouse SCD model decreases red cell density and improves several hematological parameters, supporting the strategy of combined pharmacological inhibition of these ion transport pathways in the adjunct treatment of human SCD.

KEYWORDS:

Osmotic fragility; Potassium channel; Potassium transporter; Red blood cell; Splenomegaly

PMID:
31352162
PMCID:
PMC6744291
[Available on 2020-11-01]
DOI:
10.1016/j.bcmd.2019.102346

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