Mitochondrial ROS activates PKC alpha translocation to the membrane of vagal sensory neurons.

Abstract

Hyperexcitability of airway sensory nerves can trigger disease‐associated reflexes resulting in cough and dyspnea. We have observed that mitochondrial ROS production increases hyperexcitability in nociceptive bronchopulmonary C‐fibers. We also found that this increased excitability can be blocked by the PKC inhibitor bisindolylmaleimide (BIM) I, but not the inactive PKC analog BIM V. In previous work we have shown, using a pan‐PKC antibody, that mitochondrial ROS production via Antimycin A (AntA; mitochondrial complex III Qi site inhibitor) causes translocation to the cell membrane. However, there are several PKC isoforms expressed in nociceptive neurons. We wanted to determine which isoforms were present, their distribution in nociceptive cells and whether specific isoforms were activated by AntA. Studies looking at mRNA expression have highlighted PKC alpha, beta1, beta2, delta and epsilon as abundant in nociceptors so our studies have focused on these particular isoforms. Sensory neuron cell bodies were isolated from mouse vagal ganglia. To identify nociceptive cells, we used a mouse strain that co‐expresses a red fluorescent protein (tdTomato) with the Transient Receptor Potential V1 ion channel. Cells were treated for 2 min with: vehicle, 10 μM AntA or 300 nM PMA then immediately fixed. We performed immunocytochemistry to determine cellular location of different isoforms. Of the TRPV1 expressing nociceptive cells, more than 50% were positive for any given isoform of PKC. All isoforms translocated to the membrane in response to PMA treatment. However, only PKC alpha exhibited translocation to the membrane in response to AntA treatment. In the case of PKC delta, AntA appeared to cause translocation of this isoform to the nucleus. Our experiments suggest that nociceptor hyperexcitability, in response to ROS produced via mitochondrial dysfunction, may occur through the translocation and activation of the PKC alpha isoform.Support or Funding InformationThis work was supported by the National Heart Lung and Blood Institute in Bethesda, USA(R01‐HL119802)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.