Brain endothelial cells metabolize glutamate via glutamate dehydrogenase to replenish TCA-intermediates and produce ATP under hypoglycemic conditions
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Brain endothelial cells metabolize glutamate via glutamate dehydrogenase to replenish TCA-intermediates and produce ATP under hypoglycemic conditions. / Hinca, Sven B; Salcedo, Claudia; Wagner, Antonie; Goldeman, Charlotte; Sadat, Edris; Aibar, Marco M D; Maechler, Pierre; Brodin, Birger; Aldana, Blanca I; Helms, Hans C C.
In: Journal of Neurochemistry, Vol. 157, No. 6, 2021, p. 1861-1875.Research output: Contribution to journal › Journal article › peer-review
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T1 - Brain endothelial cells metabolize glutamate via glutamate dehydrogenase to replenish TCA-intermediates and produce ATP under hypoglycemic conditions
AU - Hinca, Sven B
AU - Salcedo, Claudia
AU - Wagner, Antonie
AU - Goldeman, Charlotte
AU - Sadat, Edris
AU - Aibar, Marco M D
AU - Maechler, Pierre
AU - Brodin, Birger
AU - Aldana, Blanca I
AU - Helms, Hans C C
N1 - This article is protected by copyright. All rights reserved.
PY - 2021
Y1 - 2021
N2 - The endothelial cells of the blood-brain barrier participate in the regulation of glutamate concentrations in the brain interstitial fluid by taking up brain glutamate. However, endothelial glutamate metabolism has not been characterized, nor is its role in brain glutamate homeostasis and endothelial energy production known. The aim of this study was to investigate endothelial glutamate dehydrogenase (GDH) expression and glutamate metabolism and probe its functional significance. Primary brain endothelial cells were isolated from bovine and mouse brains, and human brain endothelial cells were derived from induced pluripotent stem cells. GDH expression on the protein level and GDH function were investigated in the model systems using western blotting, confocal microscopy, 13 C-glutamate metabolism and Seahorse assay. In the present study it was shown that GDH was expressed in murine and bovine brain capillaries and in cultured primary mouse and bovine brain endothelial cells as well as in human induced pluripotent stem cell-derived endothelial cells. The endothelial GDH expression was confirmed in brain capillaries from mice carrying a central nervous system specific GDH knockout. Endothelial cells from all tested species metabolized 13 C-glutamate to α-ketoglutarate, which subsequently entered the tricarboxylic acid (TCA)-cycle. Brain endothelial cells maintained mitochondrial oxygen consumption rates, when supplied with glutamate alone, whereas glutamate supplied in addition to glucose did not lead to additional oxygen consumption. In conclusion, brain endothelial cells directly take up and metabolize glutamate and utilize the resulting α-ketoglutarate in the TCA cycle to ultimately yield ATP if glucose is unavailable.
AB - The endothelial cells of the blood-brain barrier participate in the regulation of glutamate concentrations in the brain interstitial fluid by taking up brain glutamate. However, endothelial glutamate metabolism has not been characterized, nor is its role in brain glutamate homeostasis and endothelial energy production known. The aim of this study was to investigate endothelial glutamate dehydrogenase (GDH) expression and glutamate metabolism and probe its functional significance. Primary brain endothelial cells were isolated from bovine and mouse brains, and human brain endothelial cells were derived from induced pluripotent stem cells. GDH expression on the protein level and GDH function were investigated in the model systems using western blotting, confocal microscopy, 13 C-glutamate metabolism and Seahorse assay. In the present study it was shown that GDH was expressed in murine and bovine brain capillaries and in cultured primary mouse and bovine brain endothelial cells as well as in human induced pluripotent stem cell-derived endothelial cells. The endothelial GDH expression was confirmed in brain capillaries from mice carrying a central nervous system specific GDH knockout. Endothelial cells from all tested species metabolized 13 C-glutamate to α-ketoglutarate, which subsequently entered the tricarboxylic acid (TCA)-cycle. Brain endothelial cells maintained mitochondrial oxygen consumption rates, when supplied with glutamate alone, whereas glutamate supplied in addition to glucose did not lead to additional oxygen consumption. In conclusion, brain endothelial cells directly take up and metabolize glutamate and utilize the resulting α-ketoglutarate in the TCA cycle to ultimately yield ATP if glucose is unavailable.
U2 - 10.1111/jnc.15207
DO - 10.1111/jnc.15207
M3 - Journal article
C2 - 33025588
VL - 157
SP - 1861
EP - 1875
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
SN - 0022-3042
IS - 6
ER -
ID: 249773767