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Chow PH, Cox CD, Pei JV, Anabaraonye N, Nourmohammadi S, Henderson SW, Martinac B, Abdulmalik O, Yool AJ. Inhibition of the Aquaporin-1 Cation Conductance by Selected Furan Compounds Reduces Red Blood Cell Sickling. Front Pharmacol 2022; 12:794791. [PMID: 35111062 PMCID: PMC8801817 DOI: 10.3389/fphar.2021.794791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
In sickle cell disease (SCD), the pathological shift of red blood cells (RBCs) into distorted morphologies under hypoxic conditions follows activation of a cationic leak current (Psickle) and cell dehydration. Prior work showed sickling was reduced by 5-hydroxylmethyl-2-furfural (5-HMF), which stabilized mutant hemoglobin and also blocked the Psickle current in RBCs, though the molecular basis of this 5-HMF-sensitive cation current remained a mystery. Work here is the first to test the hypothesis that Aquaporin-1 (AQP1) cation channels contribute to the monovalent component of Psickle. Human AQP1 channels expressed in Xenopus oocytes were evaluated for sensitivity to 5-HMF and four derivatives known to have differential efficacies in preventing RBC sickling. Ion conductances were measured by two-electrode voltage clamp, and osmotic water permeability by optical swelling assays. Compounds tested were: 5-HMF; 5-PMFC (5-(phenoxymethyl)furan-2-carbaldehyde); 5-CMFC (5-(4-chlorophenoxymethyl)furan-2-carbaldehyde); 5-NMFC (5-(2-nitrophenoxymethyl)-furan-2-carbaldehyde); and VZHE006 (tert-butyl (5-formylfuran-2-yl)methyl carbonate). The most effective anti-sickling agent, 5-PMFC, was the most potent inhibitor of the AQP1 ion conductance (98% block at 100 µM). The order of sensitivity of the AQP1 conductance to inhibition was 5-PMFC > VZHE006 > 5-CMFC ≥ 5-NMFC, which corresponded with effectiveness in protecting RBCs from sickling. None of the compounds altered AQP1 water channel activity. Combined application of a selective AQP1 ion channel blocker AqB011 (80 µM) with a selective hemoglobin modifying agent 5-NMFC (2.5 mM) increased anti-sickling effectiveness in red blood cells from human SCD patients. Another non-selective cation channel known to be expressed in RBCs, Piezo1, was unaffected by 2 mM 5-HMF. Results suggest that inhibition of AQP1 ion channels and capacity to modify hemoglobin are combined features of the most effective anti-sickling agents. Future therapeutics aimed at both targets could hold promise for improved treatments for SCD.
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Affiliation(s)
- Pak Hin Chow
- Aquaporin Physiology and Drug Discovery Program, School of Biomedicine, University of Adelaide, Adelaide, SA, Australia
| | - Charles D Cox
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
| | - Jinxin V Pei
- Research School of Biology, College of Science, Australian National University, Canberra, ACT, Australia
| | - Nancy Anabaraonye
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Saeed Nourmohammadi
- Aquaporin Physiology and Drug Discovery Program, School of Biomedicine, University of Adelaide, Adelaide, SA, Australia
| | - Sam W Henderson
- Aquaporin Physiology and Drug Discovery Program, School of Biomedicine, University of Adelaide, Adelaide, SA, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
| | - Osheiza Abdulmalik
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Andrea J Yool
- Aquaporin Physiology and Drug Discovery Program, School of Biomedicine, University of Adelaide, Adelaide, SA, Australia
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