Epac-protein kinase C alpha signaling in purinergic P2X3R-mediated hyperalgesia after inflammation

Yanping Gu, Guangwen Li, Yong Chen, Li-Yen Huang

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Sensitization of purinergic P2X3 receptors (P2X3Rs) is a major mechanism contributing to injury-induced exaggerated pain responses. We showed in a previous study that cyclic adenosine monophosphate (cAMP)-dependent guanine nucleotide exchange factor 1 (Epac1) in rat sensory dorsal root ganglia (DRGs) is upregulated after inflammatory injury, and it plays a critical role in P2X3R sensitization by activating protein kinase C epsilon (PKCϵ) inside the cells. protein kinase C epsilon has been established as the major PKC isoform mediating injury-induced hyperalgesic responses. On the other hand, the role of PKCα in receptor sensitization was seldom considered. Here, we studied the participation of PKCα in Epac signaling in P2X3R-mediated hyperalgesia. The expression of both Epac1 and Epac2 and the level of cAMP in DRGs are greatly enhanced after complete Freund adjuvant (CFA)-induced inflammation. The expression of phosphorylated PKCα is also upregulated. Complete Freund adjuvant (CFA)-induced P2X3R-mediated hyperalgesia is not only blocked by Epac antagonists but also by the classical PKC isoform inhibitors, Go6976, and PKCα-siRNA. These CFA effects are mimicked by the application of the Epac agonist, 8-(4-chlorophenylthio)-2 -O-methyl-cAMP (CPT), in control rats, further confirming the involvement of Epacs. Because the application of Go6976 prior to CPT still reduces CPT-induced hyperalgesia, PKCα is downstream of Epacs to mediate the enhancement of P2X3R responses in DRGs. The pattern of translocation of PKCα inside DRG neurons in response to CPT or CFA stimulation is distinct from that of PKCϵ. Thus, in contrast to prevalent view, PKCα also plays an essential role in producing complex inflammation-induced receptor-mediated hyperalgesia.

Original languageEnglish (US)
Pages (from-to)1541-1550
Number of pages10
JournalPain
Volume157
Issue number7
DOIs
StatePublished - Jul 1 2016

Fingerprint

Protein Kinase C-epsilon
Protein Kinase C-alpha
Hyperalgesia
Inflammation
Freund's Adjuvant
Spinal Ganglia
Cyclic AMP
Wounds and Injuries
Protein Isoforms
Purinergic P2X3 Receptors
Sensory Ganglia
Guanine Nucleotide Exchange Factors
Adenosine Monophosphate
Small Interfering RNA

Keywords

  • DRG
  • Epac1
  • Epac2
  • inflammatory pain
  • P2X3R
  • PKCα
  • PKCϵ

ASJC Scopus subject areas

  • Clinical Neurology
  • Anesthesiology and Pain Medicine
  • Neurology
  • Pharmacology

Cite this

Epac-protein kinase C alpha signaling in purinergic P2X3R-mediated hyperalgesia after inflammation. / Gu, Yanping; Li, Guangwen; Chen, Yong; Huang, Li-Yen.

In: Pain, Vol. 157, No. 7, 01.07.2016, p. 1541-1550.

Research output: Contribution to journalArticle

@article{00db5cf6b9234e178f4bee3f3b2b91d0,
title = "Epac-protein kinase C alpha signaling in purinergic P2X3R-mediated hyperalgesia after inflammation",
abstract = "Sensitization of purinergic P2X3 receptors (P2X3Rs) is a major mechanism contributing to injury-induced exaggerated pain responses. We showed in a previous study that cyclic adenosine monophosphate (cAMP)-dependent guanine nucleotide exchange factor 1 (Epac1) in rat sensory dorsal root ganglia (DRGs) is upregulated after inflammatory injury, and it plays a critical role in P2X3R sensitization by activating protein kinase C epsilon (PKCϵ) inside the cells. protein kinase C epsilon has been established as the major PKC isoform mediating injury-induced hyperalgesic responses. On the other hand, the role of PKCα in receptor sensitization was seldom considered. Here, we studied the participation of PKCα in Epac signaling in P2X3R-mediated hyperalgesia. The expression of both Epac1 and Epac2 and the level of cAMP in DRGs are greatly enhanced after complete Freund adjuvant (CFA)-induced inflammation. The expression of phosphorylated PKCα is also upregulated. Complete Freund adjuvant (CFA)-induced P2X3R-mediated hyperalgesia is not only blocked by Epac antagonists but also by the classical PKC isoform inhibitors, Go6976, and PKCα-siRNA. These CFA effects are mimicked by the application of the Epac agonist, 8-(4-chlorophenylthio)-2 -O-methyl-cAMP (CPT), in control rats, further confirming the involvement of Epacs. Because the application of Go6976 prior to CPT still reduces CPT-induced hyperalgesia, PKCα is downstream of Epacs to mediate the enhancement of P2X3R responses in DRGs. The pattern of translocation of PKCα inside DRG neurons in response to CPT or CFA stimulation is distinct from that of PKCϵ. Thus, in contrast to prevalent view, PKCα also plays an essential role in producing complex inflammation-induced receptor-mediated hyperalgesia.",
keywords = "DRG, Epac1, Epac2, inflammatory pain, P2X3R, PKCα, PKCϵ",
author = "Yanping Gu and Guangwen Li and Yong Chen and Li-Yen Huang",
year = "2016",
month = "7",
day = "1",
doi = "10.1097/j.pain.0000000000000547",
language = "English (US)",
volume = "157",
pages = "1541--1550",
journal = "Pain",
issn = "0304-3959",
publisher = "Elsevier",
number = "7",

}

TY - JOUR

T1 - Epac-protein kinase C alpha signaling in purinergic P2X3R-mediated hyperalgesia after inflammation

AU - Gu, Yanping

AU - Li, Guangwen

AU - Chen, Yong

AU - Huang, Li-Yen

PY - 2016/7/1

Y1 - 2016/7/1

N2 - Sensitization of purinergic P2X3 receptors (P2X3Rs) is a major mechanism contributing to injury-induced exaggerated pain responses. We showed in a previous study that cyclic adenosine monophosphate (cAMP)-dependent guanine nucleotide exchange factor 1 (Epac1) in rat sensory dorsal root ganglia (DRGs) is upregulated after inflammatory injury, and it plays a critical role in P2X3R sensitization by activating protein kinase C epsilon (PKCϵ) inside the cells. protein kinase C epsilon has been established as the major PKC isoform mediating injury-induced hyperalgesic responses. On the other hand, the role of PKCα in receptor sensitization was seldom considered. Here, we studied the participation of PKCα in Epac signaling in P2X3R-mediated hyperalgesia. The expression of both Epac1 and Epac2 and the level of cAMP in DRGs are greatly enhanced after complete Freund adjuvant (CFA)-induced inflammation. The expression of phosphorylated PKCα is also upregulated. Complete Freund adjuvant (CFA)-induced P2X3R-mediated hyperalgesia is not only blocked by Epac antagonists but also by the classical PKC isoform inhibitors, Go6976, and PKCα-siRNA. These CFA effects are mimicked by the application of the Epac agonist, 8-(4-chlorophenylthio)-2 -O-methyl-cAMP (CPT), in control rats, further confirming the involvement of Epacs. Because the application of Go6976 prior to CPT still reduces CPT-induced hyperalgesia, PKCα is downstream of Epacs to mediate the enhancement of P2X3R responses in DRGs. The pattern of translocation of PKCα inside DRG neurons in response to CPT or CFA stimulation is distinct from that of PKCϵ. Thus, in contrast to prevalent view, PKCα also plays an essential role in producing complex inflammation-induced receptor-mediated hyperalgesia.

AB - Sensitization of purinergic P2X3 receptors (P2X3Rs) is a major mechanism contributing to injury-induced exaggerated pain responses. We showed in a previous study that cyclic adenosine monophosphate (cAMP)-dependent guanine nucleotide exchange factor 1 (Epac1) in rat sensory dorsal root ganglia (DRGs) is upregulated after inflammatory injury, and it plays a critical role in P2X3R sensitization by activating protein kinase C epsilon (PKCϵ) inside the cells. protein kinase C epsilon has been established as the major PKC isoform mediating injury-induced hyperalgesic responses. On the other hand, the role of PKCα in receptor sensitization was seldom considered. Here, we studied the participation of PKCα in Epac signaling in P2X3R-mediated hyperalgesia. The expression of both Epac1 and Epac2 and the level of cAMP in DRGs are greatly enhanced after complete Freund adjuvant (CFA)-induced inflammation. The expression of phosphorylated PKCα is also upregulated. Complete Freund adjuvant (CFA)-induced P2X3R-mediated hyperalgesia is not only blocked by Epac antagonists but also by the classical PKC isoform inhibitors, Go6976, and PKCα-siRNA. These CFA effects are mimicked by the application of the Epac agonist, 8-(4-chlorophenylthio)-2 -O-methyl-cAMP (CPT), in control rats, further confirming the involvement of Epacs. Because the application of Go6976 prior to CPT still reduces CPT-induced hyperalgesia, PKCα is downstream of Epacs to mediate the enhancement of P2X3R responses in DRGs. The pattern of translocation of PKCα inside DRG neurons in response to CPT or CFA stimulation is distinct from that of PKCϵ. Thus, in contrast to prevalent view, PKCα also plays an essential role in producing complex inflammation-induced receptor-mediated hyperalgesia.

KW - DRG

KW - Epac1

KW - Epac2

KW - inflammatory pain

KW - P2X3R

KW - PKCα

KW - PKCϵ

UR - http://www.scopus.com/inward/record.url?scp=84976447988&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84976447988&partnerID=8YFLogxK

U2 - 10.1097/j.pain.0000000000000547

DO - 10.1097/j.pain.0000000000000547

M3 - Article

VL - 157

SP - 1541

EP - 1550

JO - Pain

JF - Pain

SN - 0304-3959

IS - 7

ER -