Two isoforms of cyclic GMP-dependent kinase-I exhibit distinct expression patterns in the adult mouse dorsal root ganglion

Abstract

cGMP-dependent kinase-I (cGKI) is known to regulate spinal pain processing. This enzyme consists of two isoforms (cGKIα and cGKIβ) that show distinct substrate specificity and tissue distribution. It has long been believed that the α isoform is exclusively expressed in the adult dorsal root ganglion. The aim of the present study was to reexamine the expression of cGKI isoforms in the adult mouse dorsal root ganglion using isoform-specific cGKI antibodies whose specificities had been validated in the previous studies. Immunoblot and immunohistochemical analyses revealed the presence of both isoforms in the dorsal root ganglion. Moreover, cGKIα was found to be mainly expressed within the cytoplasm of small- to medium-sized peptidergic and nonpeptidegic C-fibers, whereas cGKIβ was located within the nuclei of a wide range of dorsal root ganglion neurons. In addition, glutamine synthetase-positive satellite glial cells expressed both isoforms to varying degrees. Finally, using an experimental model for neuropathic pain produced by L5 spinal nerve transection, we found that cGKIα expression was downregulated in the injured, but not in the uninjured, dorsal root ganglion. In contrast, cGKIβ expression was upregulated in both the injured and uninjured dorsal root ganglions. Also, injury-induced cGKIβ upregulation was found to occur in small-to-medium-diameter dorsal root ganglion neurons. These data thus demonstrate the existence of two differently distributed cGKI isoforms in the dorsal root ganglion, and may provide insight into the cellular and molecular mechanisms of pain.

cGMP-dependent protein kinase I in vascular smooth muscle cells improves ischemic stroke outcome in mice

“…cGKI has emerged as a key influencer of the protective effects of NO and is produced by several cell types within the brain. 60,63 cGKI is known to be expressed by smooth muscle cells within the cerebral vasculature, 60 but the specific role of cGKI residing within those cells in regulating cerebral ischemia/reperfusion injury is not entirely understood. In the present study, we employed a recently discovered 40 mouse model of smooth muscle cell-specific cGKI deficiency to investigate the role of vascular cGMP signaling in stroke outcome.…”

cGMP signalling in dorsal root ganglia and the spinal cord: Various functions in development and adulthood

“…4). PKG1α, the major isoform of the enzyme in the cytosol of sensory neurons (Uchida, Matsumura et al, 2018), can also be activated by oxidants that are able to cause an interprotein disulfide bond formation between two cysteine This article is protected by copyright. All rights reserved.…”

“…With regard to cGMP signalling it should be noted that activation of PKG1 can also be driven by cGMP-independent mechanisms (Figure 4). PKG1α, the major isoform of the enzyme in the cytosol of sensory neurons (Uchida et al, 2018), can also be activated by oxidants that are able to cause an interprotein disulfide bond formation between two cysteine residues (Cys 42 ) on adjacent chains in the PKG1α homodimer. This reaction renders the kinase catalytically active, independently of cGMP (Burgoyne et al, 2007).…”

Animal Models of Peripheral Pain: Biology Review and Application for Drug Discovery

“…151 The presence and expression patterns of proteins of interest may be evaluated by immunofluorescence or immunohistochemical staining. [152][153][154] When assessing behavioral end points, it is important to establish that animals were evaluated in the absence of spontaneous disease or influence of comorbidities of the model. Otherwise, these effects can greatly influence and even invalidate study results.…”

“…151 The presence and expression patterns of proteins of interest may be evaluated by immunofluorescence or immunohistochemical staining. 152 -154…”