Limits...
Involvement of CX3CL1/CX3CR1 signaling in spinal long term potentiation.

Bian C, Zhao ZQ, Zhang YQ, Lü N - PLoS ONE (2015)

Bottom Line: Exogenous CX3CL1 significantly potentiated 3-trains TSS-induced LTP in rats.Consistently, spinal LTP of C-fiber-evoked field potentials was also induced by TSS (100 Hz, 1s, 4 trains) in all C57BL/6 wild type (WT) mice.These results suggest that CX3CL1/CX3CR1 signaling is involved in LTP of C-fiber-evoked field potentials in the rodent spinal dorsal horn.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.

ABSTRACT
The long-term potentiation (LTP) of spinal C-fiber-evoked field potentials is considered as a fundamental mechanism of central sensitization in the spinal cord. Accumulating evidence has showed the contribution of spinal microglia to spinal LTP and pathological pain. As a key signaling of neurons-microglia interactions, the involvement of CX3CL1/CX3CR1 signaling in pathological pain has also been investigated extensively. The present study examined whether CX3CL1/CX3CR1 signaling plays a role in spinal LTP. The results showed that 10-trains tetanic stimulation (100 Hz, 2s) of the sciatic nerve (TSS) produced a significant LTP of C-fiber-evoked field potentials lasting for over 3 h in the rat spinal dorsal horn. Blockade of CX3CL1/CX3CR1 signaling with an anti-CX3CR1 neutralizing antibody (CX3CR1 AB) markedly suppressed TSS-induced LTP. Exogenous CX3CL1 significantly potentiated 3-trains TSS-induced LTP in rats. Consistently, spinal LTP of C-fiber-evoked field potentials was also induced by TSS (100 Hz, 1s, 4 trains) in all C57BL/6 wild type (WT) mice. However, in CX3CR1-/- mice, TSS failed to induce LTP and behavioral hypersensitivity, confirming an essential role of CX3CR1 in spinal LTP induction. Furthermore, blockade of IL-18 or IL-23, the potential downstream factors of CX3CL1/CX3CR1 signaling, with IL-18 BP or anti-IL-23 neutralizing antibody (IL-23 AB), obviously suppressed spinal LTP in rats. These results suggest that CX3CL1/CX3CR1 signaling is involved in LTP of C-fiber-evoked field potentials in the rodent spinal dorsal horn.

No MeSH data available.


Related in: MedlinePlus

Involvement of CX3CL1 in spinal LTP.(A) As compared with 10-trains TSS-induced LTP, 3-trains TSS induced a LTP with smaller potentiated extent. While exogenous CX3CL1 (0.75 μg/30 μl) was applied 30 min before TSS, 3-trains TSS-induced LTP was robustly potentiated. (B) The facilitative effect of exogenous CX3CL1 (0.75 μg/30 μl) on 3 trains TSS-induced LTP was completely blocked by CX3CR1 AB (30 μg/30 μl), which was applied 2 h before TSS (1.5 h before delivering CX3CL1). (C) There was a delayed facilitative effect of 3.75 μg/30 μl exogenous CX3CL1 on baseline C-response, as compared with control PBS, and no influence of CX3CL1 was observed on baseline C-response at the dose of 0.75 μg/30 μl. (D) Western blot showed 30 min after 10-trains TSS, the expression of membrane-bound CX3CL1 was evidently reduced in the spinal dorsal horn, whereas soluble CX3CL1 level was upregulated in spinal CSF. Inset: the membrane-bound CX3CL1 and soluble CX3CL1 were detected at the 95 kDa and 72 kDa band respectively in the spinal dorsal horn (SDH) and CSF by an anti-CX3CL1 antibody. (E) ELASA assay showed that soluble CX3CL1 in the CSF was significantly upregulated at 30 min after TSS. (F) Western blot showed that Cathepsin S level was upregulated in the CSF at 30 min after TSS. * p<0.05 vs. Sham control.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4358970&req=5

pone.0118842.g004: Involvement of CX3CL1 in spinal LTP.(A) As compared with 10-trains TSS-induced LTP, 3-trains TSS induced a LTP with smaller potentiated extent. While exogenous CX3CL1 (0.75 μg/30 μl) was applied 30 min before TSS, 3-trains TSS-induced LTP was robustly potentiated. (B) The facilitative effect of exogenous CX3CL1 (0.75 μg/30 μl) on 3 trains TSS-induced LTP was completely blocked by CX3CR1 AB (30 μg/30 μl), which was applied 2 h before TSS (1.5 h before delivering CX3CL1). (C) There was a delayed facilitative effect of 3.75 μg/30 μl exogenous CX3CL1 on baseline C-response, as compared with control PBS, and no influence of CX3CL1 was observed on baseline C-response at the dose of 0.75 μg/30 μl. (D) Western blot showed 30 min after 10-trains TSS, the expression of membrane-bound CX3CL1 was evidently reduced in the spinal dorsal horn, whereas soluble CX3CL1 level was upregulated in spinal CSF. Inset: the membrane-bound CX3CL1 and soluble CX3CL1 were detected at the 95 kDa and 72 kDa band respectively in the spinal dorsal horn (SDH) and CSF by an anti-CX3CL1 antibody. (E) ELASA assay showed that soluble CX3CL1 in the CSF was significantly upregulated at 30 min after TSS. (F) Western blot showed that Cathepsin S level was upregulated in the CSF at 30 min after TSS. * p<0.05 vs. Sham control.

Mentions: To further verify the contribution of CX3CL1/CX3CR1 signaling to spinal LTP, exogenous CX3CL1 was applied to test whether LTP was facilitated. Considering spinal LTP could be saturated by strong stimulation of sciatic nerve [33], 3-trains TSS was used to induce spinal LTP to avoid the potential ceiling effect of 10-trains TSS on LTP in rats. The results showed that 3-trains TSS induced LTP with smaller potentiated extent than that of 10-trains TSS-induced LTP, and 3-trains TSS-induced LTP was robustly potentiated by spinal application of CX3CL1 (0.75 μg/30 μl) 30 min before 3-trains TSS (Two-way ANOVA, treatments: F2, 18 = 6.618, p < 0.01) (Fig. 4A).


Involvement of CX3CL1/CX3CR1 signaling in spinal long term potentiation.

Bian C, Zhao ZQ, Zhang YQ, Lü N - PLoS ONE (2015)

Involvement of CX3CL1 in spinal LTP.(A) As compared with 10-trains TSS-induced LTP, 3-trains TSS induced a LTP with smaller potentiated extent. While exogenous CX3CL1 (0.75 μg/30 μl) was applied 30 min before TSS, 3-trains TSS-induced LTP was robustly potentiated. (B) The facilitative effect of exogenous CX3CL1 (0.75 μg/30 μl) on 3 trains TSS-induced LTP was completely blocked by CX3CR1 AB (30 μg/30 μl), which was applied 2 h before TSS (1.5 h before delivering CX3CL1). (C) There was a delayed facilitative effect of 3.75 μg/30 μl exogenous CX3CL1 on baseline C-response, as compared with control PBS, and no influence of CX3CL1 was observed on baseline C-response at the dose of 0.75 μg/30 μl. (D) Western blot showed 30 min after 10-trains TSS, the expression of membrane-bound CX3CL1 was evidently reduced in the spinal dorsal horn, whereas soluble CX3CL1 level was upregulated in spinal CSF. Inset: the membrane-bound CX3CL1 and soluble CX3CL1 were detected at the 95 kDa and 72 kDa band respectively in the spinal dorsal horn (SDH) and CSF by an anti-CX3CL1 antibody. (E) ELASA assay showed that soluble CX3CL1 in the CSF was significantly upregulated at 30 min after TSS. (F) Western blot showed that Cathepsin S level was upregulated in the CSF at 30 min after TSS. * p<0.05 vs. Sham control.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4358970&req=5

pone.0118842.g004: Involvement of CX3CL1 in spinal LTP.(A) As compared with 10-trains TSS-induced LTP, 3-trains TSS induced a LTP with smaller potentiated extent. While exogenous CX3CL1 (0.75 μg/30 μl) was applied 30 min before TSS, 3-trains TSS-induced LTP was robustly potentiated. (B) The facilitative effect of exogenous CX3CL1 (0.75 μg/30 μl) on 3 trains TSS-induced LTP was completely blocked by CX3CR1 AB (30 μg/30 μl), which was applied 2 h before TSS (1.5 h before delivering CX3CL1). (C) There was a delayed facilitative effect of 3.75 μg/30 μl exogenous CX3CL1 on baseline C-response, as compared with control PBS, and no influence of CX3CL1 was observed on baseline C-response at the dose of 0.75 μg/30 μl. (D) Western blot showed 30 min after 10-trains TSS, the expression of membrane-bound CX3CL1 was evidently reduced in the spinal dorsal horn, whereas soluble CX3CL1 level was upregulated in spinal CSF. Inset: the membrane-bound CX3CL1 and soluble CX3CL1 were detected at the 95 kDa and 72 kDa band respectively in the spinal dorsal horn (SDH) and CSF by an anti-CX3CL1 antibody. (E) ELASA assay showed that soluble CX3CL1 in the CSF was significantly upregulated at 30 min after TSS. (F) Western blot showed that Cathepsin S level was upregulated in the CSF at 30 min after TSS. * p<0.05 vs. Sham control.
Mentions: To further verify the contribution of CX3CL1/CX3CR1 signaling to spinal LTP, exogenous CX3CL1 was applied to test whether LTP was facilitated. Considering spinal LTP could be saturated by strong stimulation of sciatic nerve [33], 3-trains TSS was used to induce spinal LTP to avoid the potential ceiling effect of 10-trains TSS on LTP in rats. The results showed that 3-trains TSS induced LTP with smaller potentiated extent than that of 10-trains TSS-induced LTP, and 3-trains TSS-induced LTP was robustly potentiated by spinal application of CX3CL1 (0.75 μg/30 μl) 30 min before 3-trains TSS (Two-way ANOVA, treatments: F2, 18 = 6.618, p < 0.01) (Fig. 4A).

Bottom Line: Exogenous CX3CL1 significantly potentiated 3-trains TSS-induced LTP in rats.Consistently, spinal LTP of C-fiber-evoked field potentials was also induced by TSS (100 Hz, 1s, 4 trains) in all C57BL/6 wild type (WT) mice.These results suggest that CX3CL1/CX3CR1 signaling is involved in LTP of C-fiber-evoked field potentials in the rodent spinal dorsal horn.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.

ABSTRACT
The long-term potentiation (LTP) of spinal C-fiber-evoked field potentials is considered as a fundamental mechanism of central sensitization in the spinal cord. Accumulating evidence has showed the contribution of spinal microglia to spinal LTP and pathological pain. As a key signaling of neurons-microglia interactions, the involvement of CX3CL1/CX3CR1 signaling in pathological pain has also been investigated extensively. The present study examined whether CX3CL1/CX3CR1 signaling plays a role in spinal LTP. The results showed that 10-trains tetanic stimulation (100 Hz, 2s) of the sciatic nerve (TSS) produced a significant LTP of C-fiber-evoked field potentials lasting for over 3 h in the rat spinal dorsal horn. Blockade of CX3CL1/CX3CR1 signaling with an anti-CX3CR1 neutralizing antibody (CX3CR1 AB) markedly suppressed TSS-induced LTP. Exogenous CX3CL1 significantly potentiated 3-trains TSS-induced LTP in rats. Consistently, spinal LTP of C-fiber-evoked field potentials was also induced by TSS (100 Hz, 1s, 4 trains) in all C57BL/6 wild type (WT) mice. However, in CX3CR1-/- mice, TSS failed to induce LTP and behavioral hypersensitivity, confirming an essential role of CX3CR1 in spinal LTP induction. Furthermore, blockade of IL-18 or IL-23, the potential downstream factors of CX3CL1/CX3CR1 signaling, with IL-18 BP or anti-IL-23 neutralizing antibody (IL-23 AB), obviously suppressed spinal LTP in rats. These results suggest that CX3CL1/CX3CR1 signaling is involved in LTP of C-fiber-evoked field potentials in the rodent spinal dorsal horn.

No MeSH data available.


Related in: MedlinePlus