Abstract:The aim of the present study was to investigate whether the MAPK pathways were involved in the mechanism of neuropathic pain in rats with chronic compression of the dorsal root ganglion. We determined the paw withdrawal mechanical threshold (PWMT) of rats before and after CCD surgery and then after p38, JNK, or ERK inhibitors administration. Western blotting, RT-PCR, and immunofluorescence of dorsal root ganglia were performed to investigate the protein and mRNA level of MAPKs and also the alternation in distr… Show more
“…Our study demonstrated that the specific JNK activation inhibitor SP600125, ERK1/2 activation inhibitor UO126 and p38 activation inhibitor SB203580 significantly blocked the gene expression of IL-10 and POMC in cultured microglia. The results agree with previous findings in which each subtype of MAPKs was involved in the production of IL-10 in human alveolar macrophages and monocytes [7,28,29,39,58,63,64,93]. These results suggest that each ERK1/2, JNK, and p38 MAPK activation is associated with cinobufagin-induced expression of IL-10 after activation of α7-nAChRs.…”
Background: Cinobufagin is the major bufadienolide of Bufonis venenum (Chansu), which has been traditionally used for the treatment of chronic pain especially cancer pain. The current study aimed to evaluate its antinociceptive effects in bone cancer pain and explore the underlying mechanisms. Methods: Rat bone cancer model was used in this study. The withdrawal threshold evoked by stimulation of the hindpaw was determined using a 2290 CE electrical von Frey hair. The β-endorphin and IL-10 levels were measured in the spinal cord and cultured primary microglia, astrocytes, and neurons. Results: Cinobufagin, given intrathecally, dose-dependently attenuated mechanical allodynia in bone cancer pain rats, with the projected E max of 90% MPE and ED 50 of 6.4 μg. Intrathecal cinobufagin also stimulated the gene and protein expression of IL-10 and β-endorphin (but not dynorphin A) in the spinal cords of bone cancer pain rats. In addition, treatment with cinobufagin in cultured primary spinal microglia but not astrocytes or neurons stimulated the mRNA and protein expression of IL-10 and β-endorphin, which was prevented by the pretreatment with the IL-10 antibody but not β-endorphin antiserum. Furthermore, spinal cinobufagin-induced mechanical antiallodynia was inhibited by the pretreatment with intrathecal injection of the microglial inhibitor minocycline, IL-10 antibody, βendorphin antiserum and specific μ-opioid receptor antagonist CTAP. Lastly, cinobufagin-and the specific α-7 nicotinic acetylcholine receptor (α7-nAChR) agonist PHA-543613-induced microglial gene expression of IL-10/βendorphin and mechanical antiallodynia in bone cancer pain were blocked by the pretreatment with the specific α7-nAChR antagonist methyllycaconitine. Conclusions: Our results illustrate that cinobufagin produces mechanical antiallodynia in bone cancer pain through spinal microglial expression of IL-10 and subsequent β-endorphin following activation of α7-nAChRs. Our results also highlight the broad significance of the recently uncovered spinal microglial IL-10/β-endorphin pathway in antinociception.
“…Our study demonstrated that the specific JNK activation inhibitor SP600125, ERK1/2 activation inhibitor UO126 and p38 activation inhibitor SB203580 significantly blocked the gene expression of IL-10 and POMC in cultured microglia. The results agree with previous findings in which each subtype of MAPKs was involved in the production of IL-10 in human alveolar macrophages and monocytes [7,28,29,39,58,63,64,93]. These results suggest that each ERK1/2, JNK, and p38 MAPK activation is associated with cinobufagin-induced expression of IL-10 after activation of α7-nAChRs.…”
Background: Cinobufagin is the major bufadienolide of Bufonis venenum (Chansu), which has been traditionally used for the treatment of chronic pain especially cancer pain. The current study aimed to evaluate its antinociceptive effects in bone cancer pain and explore the underlying mechanisms. Methods: Rat bone cancer model was used in this study. The withdrawal threshold evoked by stimulation of the hindpaw was determined using a 2290 CE electrical von Frey hair. The β-endorphin and IL-10 levels were measured in the spinal cord and cultured primary microglia, astrocytes, and neurons. Results: Cinobufagin, given intrathecally, dose-dependently attenuated mechanical allodynia in bone cancer pain rats, with the projected E max of 90% MPE and ED 50 of 6.4 μg. Intrathecal cinobufagin also stimulated the gene and protein expression of IL-10 and β-endorphin (but not dynorphin A) in the spinal cords of bone cancer pain rats. In addition, treatment with cinobufagin in cultured primary spinal microglia but not astrocytes or neurons stimulated the mRNA and protein expression of IL-10 and β-endorphin, which was prevented by the pretreatment with the IL-10 antibody but not β-endorphin antiserum. Furthermore, spinal cinobufagin-induced mechanical antiallodynia was inhibited by the pretreatment with intrathecal injection of the microglial inhibitor minocycline, IL-10 antibody, βendorphin antiserum and specific μ-opioid receptor antagonist CTAP. Lastly, cinobufagin-and the specific α-7 nicotinic acetylcholine receptor (α7-nAChR) agonist PHA-543613-induced microglial gene expression of IL-10/βendorphin and mechanical antiallodynia in bone cancer pain were blocked by the pretreatment with the specific α7-nAChR antagonist methyllycaconitine. Conclusions: Our results illustrate that cinobufagin produces mechanical antiallodynia in bone cancer pain through spinal microglial expression of IL-10 and subsequent β-endorphin following activation of α7-nAChRs. Our results also highlight the broad significance of the recently uncovered spinal microglial IL-10/β-endorphin pathway in antinociception.
“…2b). The identified KEGG pathways in the ipsi cell body compartment have been associated with peripheral neuropathy 29–33 or neuron growth and development 34, 35 .Figure 2RNA-Seq analysis of enriched mRNAs in cell body and axon compartments. ( a ) Analysis of RNA-Seq reads processed by STAR aligner and DESeq2 revealed mRNA profiles in axon and cell body compartments of SNE ipsi and contralateral DRG neurons.…”
Neuronal cells express considerable plasticity responding to environmental cues, in part, through subcellular mRNA regulation. Here we report on the extensive changes in distribution of mRNAs in the cell body and axon compartments of peripheral sensory neurons and the 3′ untranslated region (3′UTR) landscapes after unilateral sciatic nerve entrapment (SNE) injury in rats. Neuronal cells dissociated from SNE-injured and contralateral L4 and L5 dorsal root ganglia were cultured in a compartmentalized system. Axonal and cell body RNA samples were separately subjected to high throughput RNA sequencing (RNA-Seq). The injured axons exhibited enrichment of mRNAs related to protein synthesis and nerve regeneration. Lengthening of 3′UTRs was more prevalent in the injured axons, including the newly discovered alternative cleavage and polyadenylation of NaV1.8 mRNA. Alternative polyadenylation was largely independent from the relative abundance of axonal mRNAs; but they were highly clustered in functional pathways related to RNA granule formation in the injured axons. These RNA-Seq data analyses indicate that peripheral nerve injury may result in highly selective mRNA enrichment in the affected axons with 3′UTR alterations potentially contributing to the mechanism of neuropathic pain.
“…MAPK pathways effectively attenuated SNL in rats with chronic compression of the dorsal root ganglion (Qu et al, 2016). Therefore, the GO function analysis results for the conjunct DEGs at 7th and 28th day after surgery suggested that MAPK pathways and Cox subunits may play a pivotal role in regulating the nociceptive transmission.…”
Section: Complicated Respondence Of Degs With Time After Surgerymentioning
Neuropathic pain (NP) is an intractable disease accompanying with allodynia, hyperalgesia and spontaneous pain. Accumulating evidence suggested that large volume of neurotransmitters, genes, and signaling pathways were implicated with the initiation and development of NP, while the underlying mechanism still remained poorly understood. Therefore, it was extremely important to further elucidate the potential regulatory networks for developing appropriate treatment options. Here, the RNA-Seq high-throughput sequencing was employed to determine the genes expression change in mice undergoing spinal nerve ligation (SNL). Meanwhile, the differentially expressed genes (DEGs) were analyzed by using integrated Differential Expression and Pathway analysis (iDEP) tools and String database. Then, quantitative real-time PCR (qRT-PCR) was employed to detect the expression of hub gens. The results showed that the DEGs mainly comprised 1712 upregulated and 1515 downregulated genes at 7 days, and consisted of 243 upregulated and 357 downregulated genes at 28 days after surgery, respectively. Additionally, 133 genes and two pathways including retrograde endocannabinoid signaling and cardiac muscle contraction collectively participated in biological reactions of 7th and 28th day after operation. Moreover, the results showed that the mRNA and protein expression of Ccl5, Cacna2d1, Cacna2d2, Cacnb2, Gabrb3, GluA1, and GluA2 were significantly upregulated in SNL-7/28d group than that of in Sham-7/28d group (SNL-7d vs. Sham-7d; SNL-28d vs. Sham-28d; P < 0.05). And the level of Glra2, Glra4, Glra3, Grik1, Grik2, NR1, NR2A, and NR2B was obviously increased in SNL-7d group compared to Sham-7d group (P < 0.05), but which was no statistical difference between SNL-28d group and Sham-28d group. Therefore, these results provided new perspectives and strategies for deeply illuminating the underlying mechanism, and identifying the key elements for treating NP.
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