The loss-of-function disease-mutation G301R in the Na+/K+-ATPase α2 isoform decreases lesion volume and improves functional outcome after spinal cord injury in mice

Ditte Gry Ellman, Toke Jost Isaksen, Minna Christiansen Lund, Safinaz Dursun, Martin Wirenfeldt, Louise Helskov Jørgensen, Karin Lykke-Hartmann, Kate Lykke Lambertsen

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Resumé

BACKGROUND: The Na(+)/K(+)-ATPases are transmembrane ion pumps important for maintenance of ion gradients across the plasma membrane that serve to support multiple cellular functions, such as membrane potentials, regulation of cellular volume and pH, and co-transport of signaling transmitters in all animal cells. The α2Na(+)/K(+)-ATPase subunit isoform is predominantly expressed in astrocytes, which us the sharp Na(+)-gradient maintained by the sodium pump necessary for astroglial metabolism. Prolonged ischemia induces an elevation of [Na(+)]i, decreased ATP levels and intracellular pH owing to anaerobic metabolism and lactate accumulation. During ischemia, Na(+)/K(+)-ATPase-related functions will naturally increase the energy demand of the Na(+)/K(+)-ATPase ion pump. However, the role of the α2Na(+)/K(+)-ATPase in contusion injury to the spinal cord remains unknown. We used mice heterozygous mice for the loss-of-function disease-mutation G301R in the Atp1a2 gene (α 2(+/G301R) ) to study the effect of reduced α2Na(+)/K(+)-ATPase expression in a moderate contusion spinal cord injury (SCI) model.

RESULTS: We found that α 2(+/G301R) mice display significantly improved functional recovery and decreased lesion volume compared to littermate controls (α 2(+/+) ) 7 days after SCI. The protein level of the α1 isoform was significantly increased, in contrast to the α3 isoform that significantly decreased 3 days after SCI in both α 2(+/G301R) and α 2(+/+) mice. The level of the α2 isoform was significantly decreased in α 2(+/G301R) mice both under naïve conditions and 3 days after SCI compared to α 2(+/+) mice. We found no differences in astroglial aquaporin 4 levels and no changes in the expression of chemokines (CCL2, CCL5 and CXCL1) and cytokines (TNF, IL-6, IL-1β, IL-10 and IL-5) between genotypes, just as no apparent differences were observed in location and activation of CD45 and F4/80 positive microglia and infiltrating leukocytes.

CONCLUSION: Our proof of concept study demonstrates that reduced expression of the α2 isoform in the spinal cord is protective following SCI. Importantly, the BMS and lesion volume were assessed at 7 days after SCI, and longer time points after SCI were not evaluated. However, the α2 isoform is a potential possible target of therapeutic strategies for the treatment of SCI.

OriginalsprogEngelsk
Artikelnummer66
TidsskriftB M C Neuroscience
Vol/bind18
Antal sider13
ISSN1471-2202
DOI
StatusUdgivet - 2017

Fingeraftryk

Protein Isoforms
Mutation
Adenosine Triphosphatases
Contusions
sodium-translocating ATPase
Sodium-Potassium-Exchanging ATPase
Chemokine CCL5
Chemokine CCL2
Interleukin-5
Microglia
Interleukin-10
Lactic Acid
Interleukin-6
Maintenance
Cell Membrane
Ions
Proteins

Citer dette

@article{7cc721e0335141eb876e880bf5f953f4,
title = "The loss-of-function disease-mutation G301R in the Na+/K+-ATPase α2 isoform decreases lesion volume and improves functional outcome after spinal cord injury in mice",
abstract = "BACKGROUND: The Na(+)/K(+)-ATPases are transmembrane ion pumps important for maintenance of ion gradients across the plasma membrane that serve to support multiple cellular functions, such as membrane potentials, regulation of cellular volume and pH, and co-transport of signaling transmitters in all animal cells. The α2Na(+)/K(+)-ATPase subunit isoform is predominantly expressed in astrocytes, which us the sharp Na(+)-gradient maintained by the sodium pump necessary for astroglial metabolism. Prolonged ischemia induces an elevation of [Na(+)]i, decreased ATP levels and intracellular pH owing to anaerobic metabolism and lactate accumulation. During ischemia, Na(+)/K(+)-ATPase-related functions will naturally increase the energy demand of the Na(+)/K(+)-ATPase ion pump. However, the role of the α2Na(+)/K(+)-ATPase in contusion injury to the spinal cord remains unknown. We used mice heterozygous mice for the loss-of-function disease-mutation G301R in the Atp1a2 gene (α 2(+/G301R) ) to study the effect of reduced α2Na(+)/K(+)-ATPase expression in a moderate contusion spinal cord injury (SCI) model.RESULTS: We found that α 2(+/G301R) mice display significantly improved functional recovery and decreased lesion volume compared to littermate controls (α 2(+/+) ) 7 days after SCI. The protein level of the α1 isoform was significantly increased, in contrast to the α3 isoform that significantly decreased 3 days after SCI in both α 2(+/G301R) and α 2(+/+) mice. The level of the α2 isoform was significantly decreased in α 2(+/G301R) mice both under na{\"i}ve conditions and 3 days after SCI compared to α 2(+/+) mice. We found no differences in astroglial aquaporin 4 levels and no changes in the expression of chemokines (CCL2, CCL5 and CXCL1) and cytokines (TNF, IL-6, IL-1β, IL-10 and IL-5) between genotypes, just as no apparent differences were observed in location and activation of CD45 and F4/80 positive microglia and infiltrating leukocytes.CONCLUSION: Our proof of concept study demonstrates that reduced expression of the α2 isoform in the spinal cord is protective following SCI. Importantly, the BMS and lesion volume were assessed at 7 days after SCI, and longer time points after SCI were not evaluated. However, the α2 isoform is a potential possible target of therapeutic strategies for the treatment of SCI.",
author = "Ellman, {Ditte Gry} and Isaksen, {Toke Jost} and Lund, {Minna Christiansen} and Safinaz Dursun and Martin Wirenfeldt and J{\o}rgensen, {Louise Helskov} and Karin Lykke-Hartmann and Lambertsen, {Kate Lykke}",
year = "2017",
doi = "10.1186/s12868-017-0385-9",
language = "English",
volume = "18",
journal = "B M C Neuroscience",
issn = "1471-2202",
publisher = "BioMed Central",

}

The loss-of-function disease-mutation G301R in the Na+/K+-ATPase α2 isoform decreases lesion volume and improves functional outcome after spinal cord injury in mice. / Ellman, Ditte Gry; Isaksen, Toke Jost; Lund, Minna Christiansen; Dursun, Safinaz; Wirenfeldt, Martin; Jørgensen, Louise Helskov; Lykke-Hartmann, Karin; Lambertsen, Kate Lykke.

I: B M C Neuroscience, Bind 18, 66, 2017.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - The loss-of-function disease-mutation G301R in the Na+/K+-ATPase α2 isoform decreases lesion volume and improves functional outcome after spinal cord injury in mice

AU - Ellman, Ditte Gry

AU - Isaksen, Toke Jost

AU - Lund, Minna Christiansen

AU - Dursun, Safinaz

AU - Wirenfeldt, Martin

AU - Jørgensen, Louise Helskov

AU - Lykke-Hartmann, Karin

AU - Lambertsen, Kate Lykke

PY - 2017

Y1 - 2017

N2 - BACKGROUND: The Na(+)/K(+)-ATPases are transmembrane ion pumps important for maintenance of ion gradients across the plasma membrane that serve to support multiple cellular functions, such as membrane potentials, regulation of cellular volume and pH, and co-transport of signaling transmitters in all animal cells. The α2Na(+)/K(+)-ATPase subunit isoform is predominantly expressed in astrocytes, which us the sharp Na(+)-gradient maintained by the sodium pump necessary for astroglial metabolism. Prolonged ischemia induces an elevation of [Na(+)]i, decreased ATP levels and intracellular pH owing to anaerobic metabolism and lactate accumulation. During ischemia, Na(+)/K(+)-ATPase-related functions will naturally increase the energy demand of the Na(+)/K(+)-ATPase ion pump. However, the role of the α2Na(+)/K(+)-ATPase in contusion injury to the spinal cord remains unknown. We used mice heterozygous mice for the loss-of-function disease-mutation G301R in the Atp1a2 gene (α 2(+/G301R) ) to study the effect of reduced α2Na(+)/K(+)-ATPase expression in a moderate contusion spinal cord injury (SCI) model.RESULTS: We found that α 2(+/G301R) mice display significantly improved functional recovery and decreased lesion volume compared to littermate controls (α 2(+/+) ) 7 days after SCI. The protein level of the α1 isoform was significantly increased, in contrast to the α3 isoform that significantly decreased 3 days after SCI in both α 2(+/G301R) and α 2(+/+) mice. The level of the α2 isoform was significantly decreased in α 2(+/G301R) mice both under naïve conditions and 3 days after SCI compared to α 2(+/+) mice. We found no differences in astroglial aquaporin 4 levels and no changes in the expression of chemokines (CCL2, CCL5 and CXCL1) and cytokines (TNF, IL-6, IL-1β, IL-10 and IL-5) between genotypes, just as no apparent differences were observed in location and activation of CD45 and F4/80 positive microglia and infiltrating leukocytes.CONCLUSION: Our proof of concept study demonstrates that reduced expression of the α2 isoform in the spinal cord is protective following SCI. Importantly, the BMS and lesion volume were assessed at 7 days after SCI, and longer time points after SCI were not evaluated. However, the α2 isoform is a potential possible target of therapeutic strategies for the treatment of SCI.

AB - BACKGROUND: The Na(+)/K(+)-ATPases are transmembrane ion pumps important for maintenance of ion gradients across the plasma membrane that serve to support multiple cellular functions, such as membrane potentials, regulation of cellular volume and pH, and co-transport of signaling transmitters in all animal cells. The α2Na(+)/K(+)-ATPase subunit isoform is predominantly expressed in astrocytes, which us the sharp Na(+)-gradient maintained by the sodium pump necessary for astroglial metabolism. Prolonged ischemia induces an elevation of [Na(+)]i, decreased ATP levels and intracellular pH owing to anaerobic metabolism and lactate accumulation. During ischemia, Na(+)/K(+)-ATPase-related functions will naturally increase the energy demand of the Na(+)/K(+)-ATPase ion pump. However, the role of the α2Na(+)/K(+)-ATPase in contusion injury to the spinal cord remains unknown. We used mice heterozygous mice for the loss-of-function disease-mutation G301R in the Atp1a2 gene (α 2(+/G301R) ) to study the effect of reduced α2Na(+)/K(+)-ATPase expression in a moderate contusion spinal cord injury (SCI) model.RESULTS: We found that α 2(+/G301R) mice display significantly improved functional recovery and decreased lesion volume compared to littermate controls (α 2(+/+) ) 7 days after SCI. The protein level of the α1 isoform was significantly increased, in contrast to the α3 isoform that significantly decreased 3 days after SCI in both α 2(+/G301R) and α 2(+/+) mice. The level of the α2 isoform was significantly decreased in α 2(+/G301R) mice both under naïve conditions and 3 days after SCI compared to α 2(+/+) mice. We found no differences in astroglial aquaporin 4 levels and no changes in the expression of chemokines (CCL2, CCL5 and CXCL1) and cytokines (TNF, IL-6, IL-1β, IL-10 and IL-5) between genotypes, just as no apparent differences were observed in location and activation of CD45 and F4/80 positive microglia and infiltrating leukocytes.CONCLUSION: Our proof of concept study demonstrates that reduced expression of the α2 isoform in the spinal cord is protective following SCI. Importantly, the BMS and lesion volume were assessed at 7 days after SCI, and longer time points after SCI were not evaluated. However, the α2 isoform is a potential possible target of therapeutic strategies for the treatment of SCI.

U2 - 10.1186/s12868-017-0385-9

DO - 10.1186/s12868-017-0385-9

M3 - Journal article

C2 - 28886701

VL - 18

JO - B M C Neuroscience

JF - B M C Neuroscience

SN - 1471-2202

M1 - 66

ER -