title: The volume-regulated anion channel (LRRC8) in nodose neurons is sensitive to acidic pH.
abstract: The leucine rich repeat containing protein 8A (LRRC8A), or SWELL1, is an essential component of the volume-regulated anion channel (VRAC) that is activated by cell swelling and ionic strength. We report here for the first time to our knowledge its expression in a primary cell culture of nodose ganglia neurons and its localization in the soma, neurites, and neuronal membrane. We show that this neuronal VRAC/SWELL1 senses low external pH (pHo) in addition to hypoosmolarity. A robust sustained chloride current is seen in 77% of isolated nodose neurons following brief exposures to extracellular acid pH. Its activation involves proton efflux, intracellular alkalinity, and an increase in NOX-derived H2O2.The molecular identity of both the hypoosmolarity-induced and acid pHo-conditioned VRAC as LRRC8A (SWELL1) was confirmed by Cre-flox-mediated KO, shRNA-mediated knockdown, and CRISPR/Cas9-mediated LRRC8A deletion in HEK cells and in primary nodose neuronal cultures. Activation of VRAC by low pHoreduces neuronal injury during simulated ischemia and N-methyl-D-aspartate-induced (NMDA-induced) apoptosis. These results identify the VRAC (LRRC8A) as a dual sensor of hypoosmolarity and low pHoin vagal afferent neurons and define the mechanisms of its activation and its neuroprotective potential.
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Runping
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Susheel
authors.initials: S
authors.lastname: Gunasekar
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.|Veterans Affairs Medical Center, Iowa City, Iowa, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Benson
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.|Veterans Affairs Medical Center, Iowa City, Iowa, USA.|Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Chapleau
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.|Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Rajan
authors.initials: R
authors.lastname: Sah
authors.affiliation: Department of Internal Medicine.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, USA.|Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.
authors.forename: François M
authors.initials: FM
authors.lastname: Abboud
mesh_terms: D000143:Acids / Q000737:chemistry; D000818:Animals; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D019194:Ischemic Preconditioning; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D019255:NADPH Oxidases / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009994:Osmolar Concentration; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D000143:Acids; D002712:Chlorides; C000589080:LRRC8A protein, mouse; D008565:Membrane Proteins; D012333:RNA, Messenger; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases