title: Inhibition of Kv channel expression by NSAIDs depolarizes membrane potential and inhibits cell migration by disrupting calpain signaling.
abstract: Clinical use of non-steroidal anti-inflammatory drugs (NSAIDs) is well known to cause gastrointestinal ulcer formation via several mechanisms that include inhibiting epithelial cell migration and mucosal restitution. The drug-affected signaling pathways that contribute to inhibition of migration by NSAIDs are poorly understood, though previous studies have shown that NSAIDs depolarize membrane potential and suppress expression of calpain proteases and voltage-gated potassium (Kv) channel subunits. Kv channels play significant roles in cell migration and are targets of NSAID activity in white blood cells, but the specific functional effects of NSAID-induced changes in Kv channel expression, particularly on cell migration, are unknown in intestinal epithelial cells. Accordingly, we investigated the effects of NSAIDs on expression of Kv1.3, 1.4, and 1.6 in vitro and/or in vivo and evaluated the functional significance of loss of Kv subunit expression. Indomethacin or NS-398 reduced total and plasma membrane protein expression of Kv1.3 in cultured intestinal epithelial cells (IEC-6). Additionally, depolarization of membrane potential with margatoxin (MgTx), 40mM K(+), or silencing of Kv channel expression with siRNA significantly reduced IEC-6 cell migration and disrupted calpain activity. Furthermore, in rat small intestinal epithelia, indomethacin and NS-398 had significant, yet distinct, effects on gene and protein expression of Kv1.3, 1.4, or 1.6, suggesting that these may be clinically relevant targets. Our results show that inhibition of epithelial cell migration by NSAIDs is associated with decreased expression of Kv channel subunits, and provide a mechanism through which NSAIDs inhibit cell migration and may contribute to NSAID-induced gastrointestinal (GI) toxicity.
authors.affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, United States. Electronic address: ksilver@ksu.edu.
authors.forename: Kristopher
authors.initials: K
authors.lastname: Silver
authors.affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, United States.
authors.forename: Alaina
authors.initials: A
authors.lastname: Littlejohn
authors.affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, United States.
authors.forename: Laurel
authors.initials: L
authors.lastname: Thomas
authors.affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, United States.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Marsh
authors.affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, United States.
authors.forename: James D
authors.initials: JD
authors.lastname: Lillich
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002154:Calpain / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation; D051664:Kv1.3 Potassium Channel / Q000037:antagonists & inhibitors / Q000378:metabolism; D051665:Kv1.4 Potassium Channel / Q000037:antagonists & inhibitors / Q000378:metabolism; D051667:Kv1.6 Potassium Channel / Q000037:antagonists & inhibitors / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects* / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C064390:Kcna6 protein, rat; D051664:Kv1.3 Potassium Channel; D051665:Kv1.4 Potassium Channel; D051667:Kv1.6 Potassium Channel; D024642:Potassium Channels, Voltage-Gated; D002154:Calpain
keywords: Calpain; Cell migration; Indomethacin (PubChem CID: 3715); Membrane potential; NS-398 (PubChem CID: 4553); NSAID; SC-560 (PubChem CID: 4306515); Voltage-gated potassium channel