Glutamate is a regulated molecule in the mammalian testis. Extracellular regulation of glutamate in the body is determined largely by the expression of plasmalemmal glutamate transporters. We have examined by PCR, wes...Glutamate is a regulated molecule in the mammalian testis. Extracellular regulation of glutamate in the body is determined largely by the expression of plasmalemmal glutamate transporters. We have examined by PCR, western blotting and immunocytochemistry the expression of a panel of sodium-dependent plasmalemmal glutamate transporters in the rat testis. Proteins examined included： glutamate aspartate transporter （GLAST）, glutamate transporter 1 （GLT1）, excitatory amino acid carrier 1 （EAAC1）, excitatory amino acid transporter 4 （EAAT4） and EAAT5. We demonstrate that many of the glutamate transporters in the testis are alternately spliced. GLAST is present as exon-3- and exon-9-skipping forms. GLT1 was similarly present as the alternately spliced forms GLT1 b and GLTlc, whereas the abundant brain form （GLTla） was detectable only at the mRNA level. EAAT5 was also strongly expressed, whereas EAAC1 and EAAT4 were absent. These patterns of expression were compared with the patterns of endogenous glutamate localization and with patterns of D-aspartate accumulation, as assessed by immunocytochemistry. The presence of multiple glutamate transporters in the testis, including unusually spliced forms, suggests that glutamate homeostasis may be critical in this organ. The apparent presence of many of these transporters in the testis and sperm may indicate a need for glutamate transport by such cells.展开更多
The present study established a rat model of global cerebral ischemia induced by chest compression for six minutes to dynamically observe expressional changes of three glutamate transporters in the cerebral cortex and...The present study established a rat model of global cerebral ischemia induced by chest compression for six minutes to dynamically observe expressional changes of three glutamate transporters in the cerebral cortex and hippocampus. After 24 hours of ischemia, expression of glutamate transporter-1 significantly decreased in the cerebral cortex and hippocampus, which was accompanied by neuronal necrosis. At 7 days post-ischemia, expression of excitatory amino acid carrier 1 decreased in the hippocampal CA1 region and cortex, and was accompanied by apoptosis Expression of glutamate-aspartate transporter remained unchanged at 6 hours 7 days after ischemia. These results suggested that glutamate transporter levels were altered at different periods of cerebral ischemia.展开更多
Excitatory amino acid transporters(EAATs) are responsible for excitatory amino acid transportation and are associated with auto-immune diseases in the central nervous system and peripheral tissues.However, the subcell...Excitatory amino acid transporters(EAATs) are responsible for excitatory amino acid transportation and are associated with auto-immune diseases in the central nervous system and peripheral tissues.However, the subcellular location and function of EAAT2 in macrophages are still obscure. In this study,we demonstrated that LPS stimulation increases expression of EAAT2(coded by Slc1a2) via NF-κB signaling. EAAT2 is necessary for inflammatory macrophage polarization through sustaining mTORC1 activation. Mechanistically, lysosomal EAAT2 mediates lysosomal glutamate and aspartate efflux to maintain V-ATPase activation, which sustains macropinocytosis and mTORC1. We also found that mice with myeloid depletion of Slc1a2 show alleviated inflammatory responses in LPS-induced systemic inflammation and high-fat diet induced obesity. Notably, patients with type Ⅱ diabetes(T2D) have a higher level of expression of lysosomal EAAT2 and activation of mTORC1 in blood macrophages. Taken together, our study links the subcellular location of amino acid transporters with the fate decision of immune cells,which provides potential therapeutic targets for the treatment of inflammatory diseases.展开更多
文摘Glutamate is a regulated molecule in the mammalian testis. Extracellular regulation of glutamate in the body is determined largely by the expression of plasmalemmal glutamate transporters. We have examined by PCR, western blotting and immunocytochemistry the expression of a panel of sodium-dependent plasmalemmal glutamate transporters in the rat testis. Proteins examined included： glutamate aspartate transporter （GLAST）, glutamate transporter 1 （GLT1）, excitatory amino acid carrier 1 （EAAC1）, excitatory amino acid transporter 4 （EAAT4） and EAAT5. We demonstrate that many of the glutamate transporters in the testis are alternately spliced. GLAST is present as exon-3- and exon-9-skipping forms. GLT1 was similarly present as the alternately spliced forms GLT1 b and GLTlc, whereas the abundant brain form （GLTla） was detectable only at the mRNA level. EAAT5 was also strongly expressed, whereas EAAC1 and EAAT4 were absent. These patterns of expression were compared with the patterns of endogenous glutamate localization and with patterns of D-aspartate accumulation, as assessed by immunocytochemistry. The presence of multiple glutamate transporters in the testis, including unusually spliced forms, suggests that glutamate homeostasis may be critical in this organ. The apparent presence of many of these transporters in the testis and sperm may indicate a need for glutamate transport by such cells.
基金supported by the National Natural Science Foundation of China, No. 81171168Shanghai Science and Technology Committee, No. 10140903200
文摘The present study established a rat model of global cerebral ischemia induced by chest compression for six minutes to dynamically observe expressional changes of three glutamate transporters in the cerebral cortex and hippocampus. After 24 hours of ischemia, expression of glutamate transporter-1 significantly decreased in the cerebral cortex and hippocampus, which was accompanied by neuronal necrosis. At 7 days post-ischemia, expression of excitatory amino acid carrier 1 decreased in the hippocampal CA1 region and cortex, and was accompanied by apoptosis Expression of glutamate-aspartate transporter remained unchanged at 6 hours 7 days after ischemia. These results suggested that glutamate transporter levels were altered at different periods of cerebral ischemia.
基金supported by the National Natural Science Foundation of China (32225047 and U22A20510)Laboratory of Lingnan Modern Agriculture Project (NT2021005)+1 种基金National Center of Technology Innovation for Pigs (NCTIP-XD/B13)double first-class discipline promotion project (2023B10564001)。
文摘Excitatory amino acid transporters(EAATs) are responsible for excitatory amino acid transportation and are associated with auto-immune diseases in the central nervous system and peripheral tissues.However, the subcellular location and function of EAAT2 in macrophages are still obscure. In this study,we demonstrated that LPS stimulation increases expression of EAAT2(coded by Slc1a2) via NF-κB signaling. EAAT2 is necessary for inflammatory macrophage polarization through sustaining mTORC1 activation. Mechanistically, lysosomal EAAT2 mediates lysosomal glutamate and aspartate efflux to maintain V-ATPase activation, which sustains macropinocytosis and mTORC1. We also found that mice with myeloid depletion of Slc1a2 show alleviated inflammatory responses in LPS-induced systemic inflammation and high-fat diet induced obesity. Notably, patients with type Ⅱ diabetes(T2D) have a higher level of expression of lysosomal EAAT2 and activation of mTORC1 in blood macrophages. Taken together, our study links the subcellular location of amino acid transporters with the fate decision of immune cells,which provides potential therapeutic targets for the treatment of inflammatory diseases.
