WNK-SPAK/OSR1 signaling pathway facilitates ictal activity via reduced neuronal chloride extrusion rate
- 1Massachusetts General Hospital
Abstract
Seizures upregulate Na + -K + -2Cl - (NKCC1)-mediated Cl − influx and downregulate K + -Cl - (KCC2)-mediated Cl - efflux via the WNK-SPAK/OSR1 kinases, leading to cytoplasmic chloride ([Cl - ] i ) accumulation, reduced GABAergic inhibition and anticonvulsant failure. Early studies found that inhibiting WNK-kinase reduced baseline [Cl - ] i (E Cl ) and seizures via increased KCC2 activity. However, increased KCC2 activity alone should not affect E Cl whose determinants are more complex. We determined the net effects of WNK-SPAK/OSR1 pathway inhibitor WNK463 on E Cl and [Cl - ] i transients during spontaneous ictal-like discharges (ILDs). We found that WNK463 reduced interictal [Cl - ] i but did not change baseline [Cl - ] i measured in the presence of TTX. WNK463 enhanced neuronal Cl - extrusion during and after ILDs, before abolishing ILDs. Pharmacological inhibition and targeted siRNA silencing demonstrated that the anti-ictal effects of WNK463 involved both NKCC1 and KCC2. Our data support a mechanism whereby mutual NKCC1 inhibition and KCC2 activation via the WNK-SPAK/OSR1 pathway exert powerful anti-ictal effects by facilitating [Cl - ] i extrusion during ILDs.
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BibTeX
@misc{dzhala2026wnkspakosr1,
title = {{WNK-SPAK/OSR1 signaling pathway facilitates ictal activity via reduced neuronal chloride extrusion rate}},
author = {V. I. Dzhala and F. H. Shiu and N. Rahmati and A. Carroll and R. Bae and K. T. Kahle and K. Staley},
howpublished = {bioRxiv},
year = {2026},
month = jun,
doi = {10.64898/2026.06.10.731153},
url = {https://www.biorxiv.org/content/10.64898/2026.06.10.731153v2},
note = {Public domain},
}
RIS
TY - UNPB
TI - WNK-SPAK/OSR1 signaling pathway facilitates ictal activity via reduced neuronal chloride extrusion rate
AU - V. I. Dzhala
AU - F. H. Shiu
AU - N. Rahmati
AU - A. Carroll
AU - R. Bae
AU - K. T. Kahle
AU - K. Staley
PY - 2026
DA - 2026/06/10
PB - bioRxiv
DO - 10.64898/2026.06.10.731153
UR - https://www.biorxiv.org/content/10.64898/2026.06.10.731153v2
AB - Seizures upregulate Na + -K + -2Cl - (NKCC1)-mediated Cl − influx and downregulate K + -Cl - (KCC2)-mediated Cl - efflux via the WNK-SPAK/OSR1 kinases, leading to cytoplasmic chloride ([Cl - ] i ) accumulation, reduced GABAergic inhibition and anticonvulsant failure. Early studies found that inhibiting WNK-kinase reduced baseline [Cl - ] i (E Cl ) and seizures via increased KCC2 activity. However, increased KCC2 activity alone should not affect E Cl whose determinants are more complex. We determined the net effects of WNK-SPAK/OSR1 pathway inhibitor WNK463 on E Cl and [Cl - ] i transients during spontaneous ictal-like discharges (ILDs). We found that WNK463 reduced interictal [Cl - ] i but did not change baseline [Cl - ] i measured in the presence of TTX. WNK463 enhanced neuronal Cl - extrusion during and after ILDs, before abolishing ILDs. Pharmacological inhibition and targeted siRNA silencing demonstrated that the anti-ictal effects of WNK463 involved both NKCC1 and KCC2. Our data support a mechanism whereby mutual NKCC1 inhibition and KCC2 activation via the WNK-SPAK/OSR1 pathway exert powerful anti-ictal effects by facilitating [Cl - ] i extrusion during ILDs.
ER -