Loss of the AE3 Cl/HCO exchanger (Slc4a3) in mice causes an impaired cardiac force-frequency response and heart failure under some conditions but the mechanisms are not known. To better understand the functions of AE3, we performed RNA Seq analysis of AE3-null and wild-type mouse hearts and evaluated the data with respect to three hypotheses (CO disposal, facilitation of Na-loading, and recovery from an alkaline load) that have been proposed for its physiological functions. Gene Ontology and PubMatrix analyses of differentially expressed genes revealed a hypoxia response and changes in vasodilation and angiogenesis genes that strongly support the CO disposal hypothesis. Differential expression of energy metabolism genes, which indicated increased glucose utilization and decreased fatty acid utilization, were consistent with adaptive responses to perturbations of O/CO balance in AE3-null myocytes. Given that the myocardium is an obligate aerobic tissue and consumes large amounts of O, the data suggest that loss of AE3, which has the potential to extrude CO in the form of HCO, impairs O/CO balance in cardiac myocytes. These results support a model in which the AE3 Cl/HCO exchanger, coupled with parallel Cl and H-extrusion mechanisms and extracellular carbonic anhydrase, is responsible for active transport-mediated disposal of CO.
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http://dx.doi.org/10.1038/s41598-017-07585-y | DOI Listing |
J Physiol Sci
February 2022
Department of Human Nutrition, Nagoya University Graduate School of Medicine, Nagoya, Japan.
HCO secretion in distal airways is critical for airway mucosal defense. HCO/H transport across the apical membrane of airway surface epithelial cells was studied by measuring intracellular pH in luminally microperfused freshly dissected mice bronchioles. Functional studies demonstrated that CFTR, ENaC, Cl-HCO exchange, Na-H exchange, and Na-HCO cotransport are involved in apical HCO/H transport.
View Article and Find Full Text PDFFront Physiol
September 2021
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
Bicarbonate (HCO ) transport mechanisms play an essential role in the acid-base homeostasis of aquatic animals, and anion exchange protein 3 (AE3) is a membrane transport protein that exchanges Cl/HCO across the cell membrane to regulate the intracellular pH. In this study, the full-length cDNA of () was obtained from the Pacific white shrimp (). The cDNA is 4,943 bp in length, contains an open reading frame of 2,850 bp, coding for a protein of 949 amino acids with 12 transmembrane domains.
View Article and Find Full Text PDFHeart Rhythm
August 2018
Division of Cardiology, Saint Louis University, Saint Louis, Missouri; Cardiovascular Division, Washington University in Saint Louis, Saint Louis, Missouri. Electronic address:
Establishing a definition of short QT syndrome (SQTS), including symptomatology and QT-interval duration, is still a work in progress. However, it is clear , that SQTS is a rare, life-threatening, inherited heart disease presenting as sudden cardiac death (SCD) or aborted SCD in 34% and a family history of SCD in 15%. Genetic testing is important in diagnosing the disease, but to date a causative mutation is found in <25%.
View Article and Find Full Text PDFSci Rep
August 2017
Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA.
Loss of the AE3 Cl/HCO exchanger (Slc4a3) in mice causes an impaired cardiac force-frequency response and heart failure under some conditions but the mechanisms are not known. To better understand the functions of AE3, we performed RNA Seq analysis of AE3-null and wild-type mouse hearts and evaluated the data with respect to three hypotheses (CO disposal, facilitation of Na-loading, and recovery from an alkaline load) that have been proposed for its physiological functions. Gene Ontology and PubMatrix analyses of differentially expressed genes revealed a hypoxia response and changes in vasodilation and angiogenesis genes that strongly support the CO disposal hypothesis.
View Article and Find Full Text PDFJ Physiol
January 2017
Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
Key Points: A polymorphism of human AE3 is associated with idiopathic generalized epilepsy. Knockout of AE3 in mice lowers the threshold for triggering epileptic seizures. The explanations for these effects are elusive.
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