scholarly journals Protein kinase A is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis

2019 ◽  
Author(s):  
Yajun Deng ◽  
Liang Yang ◽  
Qiqi Xie ◽  
Fengbiao Yang ◽  
Guoqiang Li ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Spinal Cord ◽  
Neuropathic Pain ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Intrathecal Injection ◽  
Hub Genes ◽  
Spinal Cord Cell ◽  
P38mapk Pathway ◽  
Kinase A

Abstract Background: Neuropathic pain is a serious clinical problem to be solved. Protein kinase A (PKA) is widely distributed in the central nervous system and participates in various signal transduction pathways to regulate cell proliferation and apoptosis. However, it is unclear whether PKA is involved in neuropathic pain. This study aimed to investigate PKA expression in neuropathic pain and its possible mechanisms of involvement. Methods: The mRNA expression dataset of neuropathic pain (GSE24982) was downloaded from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) were screened using the R software. DEGs were subjected to Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. A protein-protein interaction network was constructed using the STRING database, and the Cytoscape plug-in cytoHubba was used to screen for hub genes. A spared nerve injury (SNI) rat model was established and the paw withdrawal threshold was determined using von Frey filaments. Western blotting and immunofluorescence were used to detect the expression and cellular localization of key proteins in the spinal cord, respectively. Western blotting, ELISA, and TUNEL assays were used to detect cell signal transduction, inflammation, and apoptosis, respectively. Results: Among 449 DEGs and 20 hub genes, PKA was identified as a key gene involved in neuropathic pain. After SNI, mechanical allodynia occurred, PKA expression in the spinal cord increased, the p38MAPK pathway was activated, and spinal cord inflammation and apoptosis occurred in rats. Immunofluorescence staining showed that PKA colocalized with neurons, astrocytes, and microglia, and TUNEL with GFAP, Iba-1, Neun double labeling showed that apoptotic cells were mainly neurons. Intrathecal injection of a PKA inhibitor not only relieved mechanical hyperalgesia, inflammatory reaction, and apoptosis in SNI rats, but also inhibited p38MAPK pathway activation. Intrathecal injection of a p38MAPK inhibitor attenuated mechanical hyperalgesia, inflammatory reaction, and apoptosis, but did not affect PKA expression. Conclusions: PKA is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis. This study provides novel insights that my aid in the elucidation of the pathogenesis of neuropathic pain.

scholarly journals Protein Kinase A Is Involved in Neuropathic Pain by Activating the p38MAPK Pathway to Mediate Spinal Cord Cell Apoptosis

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Yajun Deng ◽  
Liang Yang ◽  
Qiqi Xie ◽  
Fengbiao Yang ◽  
Guoqiang Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Neuropathic Pain ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Cell Apoptosis ◽  
Intrathecal Injection ◽  
Spinal Cord Cell ◽  
P38mapk Pathway ◽  
Kinase A

Neuropathic pain is a serious clinical problem to be solved. This study is aimed at investigating protein kinase A (PKA) expression in neuropathic pain and its possible mechanisms of involvement. A neuropathic pain-related gene expression dataset was downloaded from Gene Expression Omnibus, and differentially expressed genes were screened using the R software. cytoHubba was used to screen for hub genes. A spared nerve injury (SNI) rat model was established, and the paw withdrawal threshold was determined using von Frey filaments. Western blotting and immunofluorescence were used to detect the expression and cellular localization, respectively, of key proteins in the spinal cord. Western blot, ELISA, and TUNEL assays were used to detect cell signal transduction, inflammation, and apoptosis, respectively. Pka was identified as a key gene involved in neuropathic pain. After SNI, mechanical allodynia occurred, PKA expression in the spinal cord increased, the p38MAPK pathway was activated, and spinal cord inflammation and apoptosis occurred in rats. PKA colocalized with neurons, astrocytes, and microglia, and apoptotic cells were mainly neurons. Intrathecal injection of a PKA inhibitor not only relieved mechanical hyperalgesia, inflammatory reaction, and apoptosis in SNI rats but also inhibited p38MAPK pathway activation. However, intrathecal injection of a p38MAPK inhibitor attenuated mechanical hyperalgesia, inflammation, and apoptosis, but did not affect PKA expression. In conclusion, PKA is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis.

scholarly journals Protein kinase A is involved in neuropathic pain by activating the p38MAPK pathway to mediate spinal cord cell apoptosis

2020 ◽  
Author(s):  
Yajun Deng ◽  
Liang Yang ◽  
Qiqi Xie ◽  
Fengbiao Yang ◽  
Guoqiang Li ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Cell Apoptosis ◽  
Spinal Cord Cell ◽  
P38mapk Pathway ◽  
Kinase A

Abstract The authors have withdrawn this preprint from Research Square

Effects of Protein Kinase A Activation on the Responses of Primate Spinothalamic Tract Neurons to Mechanical Stimuli

2002 ◽  
Vol 88 (1) ◽  
pp. 214-221 ◽  
Author(s):  
Qing Lin ◽  
Jing Wu ◽  
William D. Willis
Keyword(s):  
Signal Transduction ◽  
Spinal Cord ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Mechanical Stimuli ◽  
Mechanical Pressure ◽  
Spinothalamic Tract ◽  
Signal Transduction Cascade ◽  
Consistent Increase ◽  
Kinase A

Behavioral and anatomical studies by our group have suggested that the protein kinase A (PKA) signal transduction cascade contributes to long-term changes in nociceptive processing at the spinal cord level. In this study, we have examined the effects of activation of the PKA cascade on the responses of spinothalamic tract (STT) neurons to peripheral mechanical stimuli in anesthetized and paralyzed monkeys. PKA in the spinal cord was activated by intra-spinal infusion of forskolin, an activator of adenylate cyclase, by microdialysis. There was a consistent increase in responses to mechanical pressure and pinch stimuli in all STT cells tested when forskolin was administered. Enhanced responses remained at relatively high levels when forskolin had been washed out for 30 min. However, in most STT cells tested (65%), the responses to brushing stimuli were not obviously changed when forskolin was given. Background activity was slightly increased when forskolin was administered. An inactive isomer of forskolin,d-forskolin, did not produce significant effects on cellular activity. The sensitization of STT cells to noxious mechanical stimuli produced by forskolin could be blocked by pretreatment of the spinal cord with the PKA inhibitor, N-[2-(( p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamine (H89). The same dose of H89 did not affect the enhanced responses to mechanical stimuli produced by activation of protein kinase G by intra-spinal infusion of 8-bromo-cGMP, indicating that the effect of forskolin was selective. The present data suggest that activation of PKA can preferentially enhance the responses of STT cells to noxious mechanical stimuli without producing an increase in responses to innocuous brushing stimuli. We speculate that the PKA signal transduction cascade may contribute more to secondary mechanical hyperalgesia than to secondary mechanical allodynia.

Regulation of spontaneous and induced resumption of meiosis in mouse oocytes by different intracellular pathways

Reproduction ◽  
2000 ◽  
pp. 377-383 ◽  
Author(s):  
L Leonardsen ◽  
A Wiersma ◽  
M Baltsen ◽  
AG Byskov ◽  
CY Andersen
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Mitogen Activated Protein Kinase ◽  
Meiotic Maturation ◽  
Mouse Oocytes ◽  
Mitogen Activated Protein ◽  
Dependent Signal ◽  
Kinase Pathway ◽  
Kinase A

The mitogen-activated protein kinase-dependent and the cAMP-protein kinase A-dependent signal transduction pathways were studied in cultured mouse oocytes during induced and spontaneous meiotic maturation. The role of the mitogen-activated protein kinase pathway was assessed using PD98059, which specifically inhibits mitogen-activated protein kinase 1 and 2 (that is, MEK1 and MEK2), which activates mitogen-activated protein kinase. The cAMP-dependent protein kinase was studied by treating oocytes with the protein kinase A inhibitor rp-cAMP. Inhibition of the mitogen-activated protein kinase pathway by PD98059 (25 micromol l(-1)) selectively inhibited the stimulatory effect on meiotic maturation by FSH and meiosis-activating sterol (that is, 4,4-dimethyl-5alpha-cholest-8,14, 24-triene-3beta-ol) in the presence of 4 mmol hypoxanthine l(-1), whereas spontaneous maturation in the absence of hypoxanthine was unaffected. This finding indicates that different signal transduction mechanisms are involved in induced and spontaneous maturation. The protein kinase A inhibitor rp-cAMP induced meiotic maturation in the presence of 4 mmol hypoxanthine l(-1), an effect that was additive to the maturation-promoting effect of FSH and meiosis-activating sterol, indicating that induced maturation also uses the cAMP-protein kinase A-dependent signal transduction pathway. In conclusion, induced and spontaneous maturation of mouse oocytes appear to use different signal transduction pathways.

CB2/miR-124 signaling down-regulate the expression of purinergic P2X4 and P2X7 receptor in dorsal spinal cord of CCI rats

2020 ◽  
Author(s):  
Rui Xu ◽  
Fan Yang ◽  
Lijuan Li ◽  
Xiaohong Liu ◽  
Xiaolu Lei ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Sciatic Nerve ◽  
Nerve Injury ◽  
Intrathecal Injection ◽  
Receptor Activation ◽  
Cb2 Receptor ◽  
Dorsal Spinal Cord ◽  
P38mapk Pathway ◽  
Dorsal Spinal

Abstract Background: The importance of P2X purinoceptors, CB2 receptor and microRNA-124(miR-124) in spinal cord microglia to the development of neuropathic pain was demonstrated in numerous previous studies. The upregulation of P2X4 and P2X7 receptors in spinal dorsal horn microglia is involved in the development of pain behavior caused by peripheral nerve injury. However, it is not clear whether the expression of P2X4 and P2X7 receptors at dorsal spinal cord will be influenced by CB2 receptor or miR-124 in rats after chronic sciatic nerve injury.Methods: Chronic constriction injury (CCI) of the sciatic nerve was performed in rats to induce neuropathic pain. Tests of the mechanical withdrawal threshold (MWT) were carried out to assess the response of the paw to mechanical stimulus. The expression of miR-124, P2X4, P2X7 and CB2 receptor were detected with RT-PCR. The protein expression of P2X4, P2X7 and CB2 receptor, RhoA, ROCK1, ROCK2, p-p38MAPK and p-NF-kappaBp65 was detected with Western blotting analysis. Results: Intrathecal administration of CB2 receptor agonist AM1241 significantly attenuated CCI-induced mechanical allodynia and significantly inhibited the increased expression of P2X4 and P2X7 receptors at the mRNA and protein levels, which imply that P2X4 and P2X7 receptors expression are down-regulated by AM1241 in CCI rats. Western blot analysis showed that AM1241 suppressed the elevated expression of RhoA, ROCK1, ROCK2, p-p38MAPK and NF-κBp65 in the dorsal spinal cord induced by CCI. After administration with Y-27632 (ROCK inhibitor), SB203580 (P38MAPK inhibitor) or PDTC (NF-κB inhibitor), the levels of P2X4 and P2X7 receptors expression in the dorsal spinal cord were lower than those in CCI rats, which imply that the ROCK/P38MAPK pathway and NF-κB activation may contribute to the increased expression of P2X4 and P2X7 receptor. On the other hand, in CCI rats, AM1241 treatment evoked the increased expression of CB2 receptor and miRNA-124, which can be inhibited by intrathecal injection of CB2 receptor antagonist AM630, which indicate that the increased expression of miRNA-124 may be medicated by CB2 receptor activation. In addition, the increased expression of P2X4 and P2X7 receptors in the dorsal spinal cord of CCI rats were inhibited by miRNA-124 agomir. Furthermore, intrathecal injection of miRNA-124 agomir could efficiently inhibit the ROCK/P38MAPK pathway and NF-κB activation in CCI rats. Moreover, AM1241 treatment significantly inhibited the expression of P2X4 and P2X7 receptors, and this suppression is enhanced by pretreatment with miRNA-124 agomir. On the contrast, the inhibitory effect of AM1241 on the expression of P2X4 and P2X7 receptor can be reversed by pretreatment with miRNA-124 antagomir.Conclusions: In CCI rats, intrathecal injection of AM1241 could efficiently induce the increased expression of miRNA-124, while inhibiting the ROCK/P38MAPK pathway and NF-κB activation in dorsal spinal cord. CB2 receptor/miRNA-124 signaling induced the decreased P2X4 and P2X7 receptors expression via inhibit the ROCK/P38MAPK pathway and NF-κB activation.

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