title: Increased spinal cord Na⁺-K⁺-2Cl⁻ cotransporter-1 (NKCC1) activity contributes to impairment of synaptic inhibition in paclitaxel-induced neuropathic pain.
abstract: Microtubule-stabilizing agents, such as paclitaxel (Taxol), are effective chemotherapy drugs for treating many cancers, and painful neuropathy is a major dose-limiting adverse effect. Cation-chloride cotransporters, such as Na(+)-K(+)-2Cl(-) cotransporter-1 (NKCC1) and K(+)-Cl(-) cotransporter-2 (KCC2), critically influence spinal synaptic inhibition by regulating intracellular chloride concentrations. Here we show that paclitaxel treatment in rats significantly reduced GABA-induced membrane hyperpolarization and caused a depolarizing shift in GABA reversal potential of dorsal horn neurons. However, paclitaxel had no significant effect on AMPA or NMDA receptor-mediated glutamatergic input from primary afferents to dorsal horn neurons. Paclitaxel treatment significantly increased protein levels, but not mRNA levels, of NKCC1 in spinal cords. Inhibition of NKCC1 with bumetanide reversed the paclitaxel effect on GABA-mediated hyperpolarization and GABA reversal potentials. Also, intrathecal bumetanide significantly attenuated hyperalgesia and allodynia induced by paclitaxel. Co-immunoprecipitation revealed that NKCC1 interacted with β-tubulin and β-actin in spinal cords. Remarkably, paclitaxel increased NKCC1 protein levels at the plasma membrane and reduced NKCC1 levels in the cytosol of spinal cords. In contrast, treatment with an actin-stabilizing agent had no significant effect on NKCC1 protein levels in the plasma membrane or cytosolic fractions of spinal cords. In addition, inhibition of the motor protein dynein blocked paclitaxel-induced subcellular redistribution of NKCC1, whereas inhibition of kinesin-5 mimicked the paclitaxel effect. Our findings suggest that increased NKCC1 activity contributes to diminished spinal synaptic inhibition and neuropathic pain caused by paclitaxel. Paclitaxel disrupts intracellular NKCC1 trafficking by interfering with microtubule dynamics and associated motor proteins.
authors.affiliation: From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030.
authors.forename: Shao-Rui
authors.initials: SR
authors.lastname: Chen
authors.affiliation: From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030.
authors.forename: Lihong
authors.initials: L
authors.lastname: Zhu
authors.affiliation: From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.affiliation: From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030.
authors.forename: Lei
authors.initials: L
authors.lastname: Wen
authors.affiliation: From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030.
authors.forename: Geoffroy
authors.initials: G
authors.lastname: Laumet
authors.affiliation: From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 huilinpan@mdanderson.org.
authors.forename: Hui-Lin
authors.initials: HL
authors.lastname: Pan
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects; D004594:Electrophysiology; D011992:Endosomes; D006706:Homeostasis; D016547:Kinesins / Q000378:metabolism; D008297:Male; D008870:Microtubules / Q000187:drug effects; D009437:Neuralgia / Q000139:chemically induced*; D009473:Neuronal Plasticity; D059225:Nociception; D017239:Paclitaxel / Q000009:adverse effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D064506:Solute Carrier Family 12, Member 2 / Q000378:metabolism*; D013116:Spinal Cord / Q000187:drug effects; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*; D050257:Tubulin Modulators / Q000737:chemistry
chemical_list: C521566:KIF5B protein, rat; C578879:Slc12a2 protein, rat; D064506:Solute Carrier Family 12, Member 2; D050257:Tubulin Modulators; D016547:Kinesins; D017239:Paclitaxel
keywords: Chloride Transport; GABA Receptor; Neuroscience; Neurotransmitter; Neurotransmitter Receptor; Pain; Synaptic Plasticity; Trafficking