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Deletion of glucose transporter GLUT8 in mice increases locomotor activity.

Schmidt S, Gawlik V, Hölter SM, Augustin R, Scheepers A, Behrens M, Wurst W, Gailus-Durner V, Fuchs H, Hrabé de Angelis M, Kluge R, Joost HG, Schürmann A - Behav. Genet. (2008)

Bottom Line: In addition, GLUT8 is expressed in some regions of the brain.By in situ hybridization we detected GLUT8-mRNA in hippocampus, thalamus, and cortex.However, its cellular and physiological function is still unknown.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, Nuthetal, Germany.

ABSTRACT
Transport of glucose into neuronal cells is predominantly mediated by the glucose transporters GLUT1 and GLUT3. In addition, GLUT8 is expressed in some regions of the brain. By in situ hybridization we detected GLUT8-mRNA in hippocampus, thalamus, and cortex. However, its cellular and physiological function is still unknown. Thus, GLUT8 knockout (Slc2a8 -/-) mice were used for a screening approach in the modified hole board (mHB) behavioral test to analyze the role of GLUT8 in the central nervous system. Slc2a8 -/- mice showed increased mean velocity, total distance traveled and performed more turns in the mHB test. This hyperactivity of Slc2a8 -/- mice was confirmed by monitoring locomotor activity in the home cage and voluntary activity in a running wheel. In addition, Slc2a8 -/- mice showed increased arousal as indicated by elevated defecation, reduced latency to the first defecation and a tendency to altered grooming. Furthermore, the mHB test gave evidence that Slc2a8 -/- mice exhibit a reduced risk assessment because they performed less rearings in an unprotected area and showed significantly reduced latency to stretched body posture. Our data suggest that behavioral alterations of Slc2a8 -/- mice are due to dysfunctions in neuronal processes presumably as a consequence of defects in the glucose metabolism.

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Analyses of GLUT8 expression in mouse brains by in situ hybridization. (a) 20 μm cross-sections of mouse brains were hybridized with GLUT8-specific digoxigenin-labeled riboprobes and stained by standard colorimetry as described in Material and methods. Signals were obtained with the antisense probes (left panel), whereas sections of Slc2a8−/− brains did not show signals (right panel). As an additional control, brain sections from wild-type mice were incubated with probes corresponding to the sense strands of GLUT8 (middle panels). AA, amygdala; CO, cortex; HP, hippocampus; TH, thalamus; HT, hypothalamus. (b) Genotyping of mice was performed by PCR as described in Material and methods. (c) Slc2a8 mRNA levels of Slc2a8+/+ and Slc2a8−/− littermates in hippocampus, amygdala, and hypothalamus were assayed by quantitative real time-PCR (qRT-PCR) as described in Material and methods. (d) Immunohistochemical detection of GLUT8 in the hippocampus, cortex, and thalamus. Sections of the brain from Slc2a8+/+ and Slc2a8−/− mice were fixed with paraformaldehyde and incubated with the anti-GLUT8 antiserum. The immunostaining was performed with peroxidase-conjugated secondary antibody as described in Material and methods
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Fig1: Analyses of GLUT8 expression in mouse brains by in situ hybridization. (a) 20 μm cross-sections of mouse brains were hybridized with GLUT8-specific digoxigenin-labeled riboprobes and stained by standard colorimetry as described in Material and methods. Signals were obtained with the antisense probes (left panel), whereas sections of Slc2a8−/− brains did not show signals (right panel). As an additional control, brain sections from wild-type mice were incubated with probes corresponding to the sense strands of GLUT8 (middle panels). AA, amygdala; CO, cortex; HP, hippocampus; TH, thalamus; HT, hypothalamus. (b) Genotyping of mice was performed by PCR as described in Material and methods. (c) Slc2a8 mRNA levels of Slc2a8+/+ and Slc2a8−/− littermates in hippocampus, amygdala, and hypothalamus were assayed by quantitative real time-PCR (qRT-PCR) as described in Material and methods. (d) Immunohistochemical detection of GLUT8 in the hippocampus, cortex, and thalamus. Sections of the brain from Slc2a8+/+ and Slc2a8−/− mice were fixed with paraformaldehyde and incubated with the anti-GLUT8 antiserum. The immunostaining was performed with peroxidase-conjugated secondary antibody as described in Material and methods

Mentions: Generation of Slc2a8−/− mice was described previously (Gawlik et al. 2008). Briefly, the Cre loxP system was used for generation of R1 ES cells (129S3/SvImJ background) lacking exons 5–7 of Slc2a8 in order to generate Slc2a8−/− mice. As described (Gawlik et al. 2008), a targeting vector in which exons 5 and 7 of Slc2a8 were flanked with two loxP sites, and a PGKneo/HSVtk cassette (Neo/tk) with a third loxP site which was introduced downstream of the flanked exon seven was cloned and transfected into ES cells. Homologously recombined ES cell clones carrying the targeted allele were transfected with pCre in order to express the Cre recombinase transiently. ES cells with a recombination between the 1 and the 3. loxP site carrying the deleted allele were used for a morula aggregation. Blastocysts were then transferred into a pseudopregnant (day 2.5) female mouse and male chimeric mice were mated with C57BL/6 females. Mice carrying the transgene were backcrossed with C57BL/6 mice for 3 times and subsequently intercrossed. Genotyping of mice was performed by PCR (forward primer: 5′-CATCTTCTGTGCAGTCCATC-3′, reverse primer: 5′-GGTACCAAAGGCACTCATACTG-3′) (Fig. 1b). In order to minimize phenotypical differences as a result of heterogenous genetic background of C57BL/6 and 129S3/SvlmJ we analyzed Slc2a8+/+ and Slc2a8−/− littermates of 5–7 litters at the same time for each set of experiments. Mice had free access to water and standard mice chow and were group housed in air conditioned rooms (temperature 20 ± 2°C, relative moisture 50–60%) under a 12h/12h light/dark cycle. They were kept in accordance with the NIH guidelines for the care and use of laboratory animals, and all experiments were approved by the ethics committee of the Ministry of Agriculture, Nutrition, and Forestry (State of Brandenburg, Germany).Fig. 1


Deletion of glucose transporter GLUT8 in mice increases locomotor activity.

Schmidt S, Gawlik V, Hölter SM, Augustin R, Scheepers A, Behrens M, Wurst W, Gailus-Durner V, Fuchs H, Hrabé de Angelis M, Kluge R, Joost HG, Schürmann A - Behav. Genet. (2008)

Analyses of GLUT8 expression in mouse brains by in situ hybridization. (a) 20 μm cross-sections of mouse brains were hybridized with GLUT8-specific digoxigenin-labeled riboprobes and stained by standard colorimetry as described in Material and methods. Signals were obtained with the antisense probes (left panel), whereas sections of Slc2a8−/− brains did not show signals (right panel). As an additional control, brain sections from wild-type mice were incubated with probes corresponding to the sense strands of GLUT8 (middle panels). AA, amygdala; CO, cortex; HP, hippocampus; TH, thalamus; HT, hypothalamus. (b) Genotyping of mice was performed by PCR as described in Material and methods. (c) Slc2a8 mRNA levels of Slc2a8+/+ and Slc2a8−/− littermates in hippocampus, amygdala, and hypothalamus were assayed by quantitative real time-PCR (qRT-PCR) as described in Material and methods. (d) Immunohistochemical detection of GLUT8 in the hippocampus, cortex, and thalamus. Sections of the brain from Slc2a8+/+ and Slc2a8−/− mice were fixed with paraformaldehyde and incubated with the anti-GLUT8 antiserum. The immunostaining was performed with peroxidase-conjugated secondary antibody as described in Material and methods
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2480596&req=5

Fig1: Analyses of GLUT8 expression in mouse brains by in situ hybridization. (a) 20 μm cross-sections of mouse brains were hybridized with GLUT8-specific digoxigenin-labeled riboprobes and stained by standard colorimetry as described in Material and methods. Signals were obtained with the antisense probes (left panel), whereas sections of Slc2a8−/− brains did not show signals (right panel). As an additional control, brain sections from wild-type mice were incubated with probes corresponding to the sense strands of GLUT8 (middle panels). AA, amygdala; CO, cortex; HP, hippocampus; TH, thalamus; HT, hypothalamus. (b) Genotyping of mice was performed by PCR as described in Material and methods. (c) Slc2a8 mRNA levels of Slc2a8+/+ and Slc2a8−/− littermates in hippocampus, amygdala, and hypothalamus were assayed by quantitative real time-PCR (qRT-PCR) as described in Material and methods. (d) Immunohistochemical detection of GLUT8 in the hippocampus, cortex, and thalamus. Sections of the brain from Slc2a8+/+ and Slc2a8−/− mice were fixed with paraformaldehyde and incubated with the anti-GLUT8 antiserum. The immunostaining was performed with peroxidase-conjugated secondary antibody as described in Material and methods
Mentions: Generation of Slc2a8−/− mice was described previously (Gawlik et al. 2008). Briefly, the Cre loxP system was used for generation of R1 ES cells (129S3/SvImJ background) lacking exons 5–7 of Slc2a8 in order to generate Slc2a8−/− mice. As described (Gawlik et al. 2008), a targeting vector in which exons 5 and 7 of Slc2a8 were flanked with two loxP sites, and a PGKneo/HSVtk cassette (Neo/tk) with a third loxP site which was introduced downstream of the flanked exon seven was cloned and transfected into ES cells. Homologously recombined ES cell clones carrying the targeted allele were transfected with pCre in order to express the Cre recombinase transiently. ES cells with a recombination between the 1 and the 3. loxP site carrying the deleted allele were used for a morula aggregation. Blastocysts were then transferred into a pseudopregnant (day 2.5) female mouse and male chimeric mice were mated with C57BL/6 females. Mice carrying the transgene were backcrossed with C57BL/6 mice for 3 times and subsequently intercrossed. Genotyping of mice was performed by PCR (forward primer: 5′-CATCTTCTGTGCAGTCCATC-3′, reverse primer: 5′-GGTACCAAAGGCACTCATACTG-3′) (Fig. 1b). In order to minimize phenotypical differences as a result of heterogenous genetic background of C57BL/6 and 129S3/SvlmJ we analyzed Slc2a8+/+ and Slc2a8−/− littermates of 5–7 litters at the same time for each set of experiments. Mice had free access to water and standard mice chow and were group housed in air conditioned rooms (temperature 20 ± 2°C, relative moisture 50–60%) under a 12h/12h light/dark cycle. They were kept in accordance with the NIH guidelines for the care and use of laboratory animals, and all experiments were approved by the ethics committee of the Ministry of Agriculture, Nutrition, and Forestry (State of Brandenburg, Germany).Fig. 1

Bottom Line: In addition, GLUT8 is expressed in some regions of the brain.By in situ hybridization we detected GLUT8-mRNA in hippocampus, thalamus, and cortex.However, its cellular and physiological function is still unknown.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, Nuthetal, Germany.

ABSTRACT
Transport of glucose into neuronal cells is predominantly mediated by the glucose transporters GLUT1 and GLUT3. In addition, GLUT8 is expressed in some regions of the brain. By in situ hybridization we detected GLUT8-mRNA in hippocampus, thalamus, and cortex. However, its cellular and physiological function is still unknown. Thus, GLUT8 knockout (Slc2a8 -/-) mice were used for a screening approach in the modified hole board (mHB) behavioral test to analyze the role of GLUT8 in the central nervous system. Slc2a8 -/- mice showed increased mean velocity, total distance traveled and performed more turns in the mHB test. This hyperactivity of Slc2a8 -/- mice was confirmed by monitoring locomotor activity in the home cage and voluntary activity in a running wheel. In addition, Slc2a8 -/- mice showed increased arousal as indicated by elevated defecation, reduced latency to the first defecation and a tendency to altered grooming. Furthermore, the mHB test gave evidence that Slc2a8 -/- mice exhibit a reduced risk assessment because they performed less rearings in an unprotected area and showed significantly reduced latency to stretched body posture. Our data suggest that behavioral alterations of Slc2a8 -/- mice are due to dysfunctions in neuronal processes presumably as a consequence of defects in the glucose metabolism.

Show MeSH
Related in: MedlinePlus