Protection against oxidative stress in beta thalassemia/hemoglobin E erythrocytes by inhibitors of glutathione efflux transporters

PLoS One. 2013;8(1):e55685. doi: 10.1371/journal.pone.0055685. Epub 2013 Jan 31.

Abstract

In beta thalassemia/hemoglobin E (Hb E), abnormally high levels of oxidative stress account for accelerated senescence and increased destruction of erythrocytes. The present study aimed to investigate the role of glutathione efflux transporters, namely cystic fibrosis transmembrane conductance regulator (CFTR) and multidrug resistance-associated protein 1 (MRP1), in the control of glutathione levels and protection against oxidative challenges in beta thalassemia/Hb E erythrocytes. We found that CFTR protein was expressed in the erythrocytes of beta thalassemia/Hb E patients. Treatments with GlyH-101 (50 µM), a small molecule CFTR inhibitor, and MK571 (50 µM), an MRP1 inhibitor, reduced H(2)O(2)-induced free radical generation in the erythrocytes by ∼80% and 50%, respectively. Furthermore, combined treatment with GlyH-101 and MK571 completely abolished the induction of reactive oxygen radicals. Increased oxidative stress in the erythrocytes following H(2)O(2) challenges was accompanied by a decrease in intracellular level of reduced glutathione (GSH), which was prevented by treatments with GlyH-101 and MK571. CMFDA-based assays revealed that GlyH-101 and MK571 reduced H(2)O(2)-induced glutathione efflux from the erythrocytes by 87% and 66%, respectively. Interestingly, H(2)O(2)-induced osmotic tolerance of erythrocytes, a sign of erythrocyte aging, was ameliorated by treatment with GlyH-101. Our study indicates that oxidative stress induces glutathione efflux via CFTR and MRP1 in beta thalassemia/Hb E erythrocytes. Pharmacological inhibition of glutathione efflux represents a potential therapy to delay aging and premature destruction of erythrocytes in beta thalassemia/Hb E.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Antioxidants / chemistry
  • Antioxidants / pharmacology*
  • Child
  • Erythrocytes / drug effects*
  • Erythrocytes / metabolism*
  • Female
  • Glutathione / metabolism
  • Glycine / analogs & derivatives
  • Glycine / chemistry
  • Glycine / pharmacology
  • Hemoglobin E / metabolism*
  • Humans
  • Hydrazines / chemistry
  • Hydrazines / pharmacology
  • Male
  • Membrane Transport Proteins / metabolism*
  • Osmotic Pressure / drug effects
  • Oxidative Stress / drug effects*
  • Propionates / chemistry
  • Propionates / pharmacology
  • Quinolines / chemistry
  • Quinolines / pharmacology
  • Reactive Oxygen Species / metabolism
  • Young Adult
  • beta-Thalassemia / metabolism*

Substances

  • Antioxidants
  • Hydrazines
  • Membrane Transport Proteins
  • N-(2-naphthalenyl)-((3,5-dibromo-2,4-dihydroxyphenyl)methylene)glycine hydrazide
  • Propionates
  • Quinolines
  • Reactive Oxygen Species
  • glutathione transporter
  • verlukast
  • Hemoglobin E
  • Glutathione
  • Glycine

Grants and funding

This work was supported by Mahidol University research grant (CM and SH), the Office of the Higher Education Commission and Mahidol University under the National Research Universities Initiative (CM) and an MRG5380125 grant from the Thailand Research Fund, the Office of the Higher Education Commission and Mahidol University (CM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.