Nhe5, a Na /H exchanger, is predominantly expressed in brain tissue and is proposed to act as a negative regulator of dendritic spine growth. Up to now, its physiological function in vivo remains unclear. Here we show that Nhe5-deficient mice exhibit markedly enhanced learning and memory in Morris water maze, novel object recognition, and passive avoidance task. Meanwhile, the pre- and post-synaptic components, synaptophysin (Syn) and post-synaptic density 95 (PSD95) expression levels were found increased in hippocampal regions lacking of Nhe5, suggesting a possible alterations in neuronal synaptic structure and function in Nhe5 mice. Further study reveals that Nhe5 deficiency leads to higher Bdnf expression levels, followed by increased phosphorylated TrkB and PLCγ levels, indicating that Bdnf/TrkB signaling is activated due to Nhe5 deficiency. Moreover, the corresponding brain regions of Nhe5 mice display elevated ERK/CaMKII/CREB phosphorylation levels. Taken together, these findings uncover a novel physiological function of Nhe5 in regulating learning and memory, further implying Nhe5 as a potential therapeutic target for improving cognition.
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http://dx.doi.org/10.1002/ajmg.b.32600 | DOI Listing |
Am J Med Genet B Neuropsychiatr Genet
December 2017
State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.
Nhe5, a Na /H exchanger, is predominantly expressed in brain tissue and is proposed to act as a negative regulator of dendritic spine growth. Up to now, its physiological function in vivo remains unclear. Here we show that Nhe5-deficient mice exhibit markedly enhanced learning and memory in Morris water maze, novel object recognition, and passive avoidance task.
View Article and Find Full Text PDFJ Biol Chem
November 2002
Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6, Canada.
Mammalian Na+/H+ exchangers (NHEs) are a family of integral membrane proteins that play central roles in sodium, acid-base, and cell volume homeostasis. The recently cloned NHE5 isoform is expressed predominantly in brain, but its functional and cellular properties are poorly understood. To facilitate its characterization, an epitope-tagged construct of NHE5 was ectopically expressed in nonneuronal and neuronal cells.
View Article and Find Full Text PDFJ Nephrol
November 2002
Abteilung Vegetative Physiologie und Pathophysiologie, Zentrum Physiologie, Georg-August-Universität, Göttingen, Germany.
Na+/H+ exchangers (NHEs) extrude protons from, and take up sodium ions into cells. Six isoforms, NHE-1 - NHE-6, have been cloned. NHE proteins are composed of an N-terminal domain, which most likely crosses the cell membrane 12 times and constitutes the cation exchange machinery, and a C-terminal tail, which modulates the exchanger by interacting with protein kinases and regulatory factors.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
October 2001
Center for Oral Biology in the Aab Institute of Biomedical Sciences, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
Little is known of the functional properties of the mammalian, brain-specific Na(+)/H(+) exchanger isoform 5 (NHE5). Rat NHE5 was stably expressed in NHE-deficient PS120 cells, and its activity was characterized using the fluorescent pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. NHE5 was insensitive to ethylisopropyl amiloride.
View Article and Find Full Text PDFJ Biol Chem
March 2000
Department of Physiology, McGill University, Montréal, Québec H3G 1Y6, Canada.
The recently cloned Na(+)/H(+) exchanger isoform 5 (NHE5) is expressed predominantly in brain, yet little is known about its functional properties. To facilitate its characterization, a full-length cDNA encoding human NHE5 was stably transfected into NHE-deficient Chinese hamster ovary AP-1 cells. Pharmacological analyses revealed that H(+)(i)-activated (22)Na(+) influx mediated by NHE5 was inhibited by several classes of drugs (amiloride compounds, 3-methylsulfonyl-4-piperidinobenzoyl guanidine methanesulfonate, cimetidine, and harmaline) at half-maximal concentrations that were intermediate to those determined for the high affinity NHE1 and the low affinity NHE3 isoforms, but closer to the latter.
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