Tropomyosin Receptor Kinase B Receptor Activation in the Locus Coeruleus Restores Impairment of Endogenous Analgesia at a Late Stage Following Nerve Injury in Rats

Abstract Background: Patients with neuropathic pain show reduced endogenous analgesia induced by a conditioned noxious stimulus. Here, the authors tested whether peripheral nerve injury impairs descending noradrenergic inhibition from the locus coeruleus (LC) after L5–L6 spinal nerve ligation (SNL) in rats. Methods: A subdermal injection of capsaicin was used to examine noxious stimulation–induced analgesia (NSIA), evoked LC glutamate and spinal noradrenaline release, and evoked LC neuronal activity in normal and SNL rats. The authors also examined the role of presynaptic metabotropic glutamate receptors or the astroglial glutamate transporter-1 (GLT-1). Results: SNL increased basal extracellular glutamate concentration in the LC (170.1%; 95% CI, 44.7 to 295.5; n = 15) and basal spinal cord noradrenaline release (252.1%; 95% CI, 113.6 to 391.3; n = 15), which was associated with an increased tonic LC neuronal activity and a down-regulation of GLT-1 in the LC. SNL reduced NSIA (−77.6%; 95% CI, −116.4 to −38.8; n = 14) and capsaicin evoked release of glutamate in the LC (−36.2%; 95% CI, −49.3 to −23.2; n = 8) and noradrenaline in the spinal cord (−38.8%; 95% CI, −45.1 to −32.5; n = 8). Capsaicin-evoked LC neuronal activation was masked in SNL rats. Removing autoinhibition of glutamatergic terminals by metabotropic glutamate receptor blockade or increasing GLT-1 expression by histone deacetylase inhibition restored NSIA in SNL rats. SNL-induced impairment of NSIA was mimicked in normal rats by knockdown of GLT-1 in the LC. Conclusions: These results suggest that increased extracellular glutamate in the LC consequent to down-regulation of GLT-1 contributes to LC dysfunction and impaired pain-evoked endogenous analgesia after nerve injury.

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Regulation of the Epithelial Na+ Channel by the RH Domain of G Protein-coupled Receptor Kinase, GRK2, and Gαq/11

Journal of Biological Chemistry ◽

10.1074/jbc.m111.239772 ◽

2011 ◽

Vol 286 (22) ◽

pp. 19259-19269 ◽

Cited By ~ 9

Author(s):

Il-Ha Lee ◽

Sung-Hee Song ◽

Craig R. Campbell ◽

Sharad Kumar ◽

David I. Cook ◽

...

Keyword(s):

G Protein ◽

Kinase Activity ◽

Receptor Activation ◽

Na Channel ◽

G Protein Signaling ◽

Protein Signaling ◽

Receptor Kinase ◽

G Protein Coupled Receptor ◽

G Protein Coupled ◽

Α Subunits

The G protein-coupled receptor kinase (GRK2) belongs to a family of protein kinases that phosphorylates agonist-activated G protein-coupled receptors, leading to G protein-receptor uncoupling and termination of G protein signaling. GRK2 also contains a regulator of G protein signaling homology (RH) domain, which selectively interacts with α-subunits of the Gq/11 family that are released during G protein-coupled receptor activation. We have previously reported that kinase activity of GRK2 up-regulates activity of the epithelial sodium channel (ENaC) in a Na+ absorptive epithelium by blocking Nedd4-2-dependent inhibition of ENaC. In the present study, we report that GRK2 also regulates ENaC by a mechanism that does not depend on its kinase activity. We show that a wild-type GRK2 (wtGRK2) and a kinase-dead GRK2 mutant (K220RGRK2), but not a GRK2 mutant that lacks the C-terminal RH domain (ΔRH-GRK2) or a GRK2 mutant that cannot interact with Gαq/11/14 (D110AGRK2), increase activity of ENaC. GRK2 up-regulates the basal activity of the channel as a consequence of its RH domain binding the α-subunits of Gq/11. We further found that expression of constitutively active Gαq/11 mutants significantly inhibits activity of ENaC. Conversely, co-expression of siRNA against Gαq/11 increases ENaC activity. The effect of Gαq on ENaC activity is not due to change in ENaC membrane expression and is independent of Nedd4-2. These findings reveal a novel mechanism by which GRK2 and Gq/11 α-subunits regulate the activity ENaC.

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Nerve injury induces transient locus coeruleus activation over time

Pain ◽

10.1097/j.pain.0000000000002457 ◽

2021 ◽

Vol Publish Ahead of Print ◽

Author(s):

Carmen Camarena-Delgado ◽

Meritxell Llorca-Torralba ◽

Irene Suárez-Pereira ◽

Lidia Bravo ◽

Carolina López-Martín ◽

...

Keyword(s):

Locus Coeruleus ◽

Nerve Injury ◽

Over Time

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

10.21203/rs.2.22085/v1 ◽

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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Spinal Activation of Tropomyosin Receptor Kinase-B Recovers the Impaired Endogenous Analgesia in Neuropathic Pain Rats

Anesthesia & Analgesia ◽

10.1213/ane.0000000000003592 ◽

2019 ◽

Vol 129 (2) ◽

pp. 578-586 ◽

Cited By ~ 4

Author(s):

Daiki Kato ◽

Takashi Suto ◽

Hideaki Obata ◽

Shigeru Saito

Keyword(s):

Neuropathic Pain ◽

Receptor Kinase ◽

Endogenous Analgesia

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Tyrosine receptor kinase B receptor activation reverses the impairing effects of acute nicotine on contextual fear extinction

Journal of Psychopharmacology ◽

10.1177/0269881118758305 ◽

2018 ◽

Vol 32 (3) ◽

pp. 367-372 ◽

Cited By ~ 2

Author(s):

Munir Gunes Kutlu ◽

Robert D Cole ◽

David A Connor ◽

Brendan Natwora ◽

Thomas J Gould

Keyword(s):

Receptor Activation ◽

Fear Extinction ◽

Receptor Kinase ◽

Contextual Fear ◽

Tyrosine Receptor Kinase

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Locus Coeruleus Activation Facilitates Memory Encoding and Induces Hippocampal LTD that Depends on -Adrenergic Receptor Activation

Cerebral Cortex ◽

10.1093/cercor/bhp065 ◽

2009 ◽

Vol 19 (12) ◽

pp. 2827-2837 ◽

Cited By ~ 75

Author(s):

N. Lemon ◽

S. Aydin-Abidin ◽

K. Funke ◽

D. Manahan-Vaughan

Keyword(s):

Locus Coeruleus ◽

Adrenergic Receptor ◽

Receptor Activation ◽

Memory Encoding

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Mechanistic analysis of the SERK3 elongated allele defines a role for BIR ectodomains in brassinosteroid signaling

10.1101/257543 ◽

2018 ◽

Author(s):

Ulrich Hohmann ◽

Joël Nicolet ◽

Andrea Moretti ◽

Ludwig A. Hothorn ◽

Michael Hothorn

Keyword(s):

Receptor Activation ◽

Surface Patch ◽

Receptor Kinase ◽

Leucine Rich Repeat ◽

Negative Regulators ◽

Signaling Complex ◽

The Core ◽

Mechanistic Analysis ◽

Brassinosteroid Signaling

AbstractThe leucine-rich repeat receptor kinase (LRR-RK) BRI1 requires a shape-complementary SERK co-receptor for brassinosteroid sensing and receptor activation. Interface mutations that weaken the interaction between receptor and co-receptor in vitro reduce brassinosteroid signaling responses. The SERK3 elongated (elg) allele maps to the complex interface and shows enhanced brassinosteroid signaling, but surprisingly no tighter binding to the BRI1 ectodomain in vitro. Here, we report that rather than promoting the interaction with BRI1, the elg mutation disrupts the ability of the co-receptor to interact with the ectodomains of BIR receptor pseudokinases, negative regulators of LRR-RK signaling. A conserved lateral surface patch in BIR LRR domains is required for targeting SERK co-receptors and the elg allele maps to the core of the complex interface in a 1.25 Å BIR3 - SERK1 structure. Collectively, our structural, quantitative biochemical and genetic analyses suggest that brassinosteroid signaling complex formation is negatively regulated by BIR receptor ectodomains.

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Constitutive activation of leucine-rich repeat receptor kinase signaling pathways by BAK1-interacting receptor-like kinase 3 chimera

10.1101/2020.02.18.954479 ◽

2020 ◽

Cited By ~ 2

Author(s):

Ulrich Hohmann ◽

Priya Ramakrishna ◽

Kai Wang ◽

Laura Lorenzo-Orts ◽

Joel Nicolet ◽

...

Keyword(s):

Receptor Activation ◽

Activation Mechanism ◽

Signaling Proteins ◽

Receptor Kinase ◽

Leucine Rich Repeat ◽

Protein Ligands ◽

Receptor Like Kinase ◽

Transgenic Lines ◽

Receptor Kinase Signaling ◽

Membrane Signaling

AbstractReceptor kinases with extracellular leucine-rich repeat domains (LRR-RKs) form the largest group of membrane signaling proteins in plants. LRR-RKs can sense small molecule, peptide or protein ligands, and may be activated by ligand-induced interaction with a shape complementary SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) co-receptor kinase. We have previously shown that SERKs can also form constitutive, ligand-independent complexes with the LRR ectodomains of BAK1-interacting receptor-like kinase 3 (BIR3) receptor pseudokinases, negative regulators of LRR-RK signaling. Here we report that receptor chimaera in which the extracellular LRR domain of BIR3 is fused to the cytoplasmic kinase domains of the SERK-dependent LRR-RKs BRASSINOSTEROID INSENSITIVE1, HAESA and ERECTA form tight complexes with endogenous SERK co-receptors in the absence of ligand stimulus. Expression of these chimaera under the control of the endogenous promoter of the respective LRR-RK leads to strong gain-of-function brassinosteroid, floral abscission and stomatal patterning phenotypes, respectively. Importantly, a BIR3-GSO1/SGN3 chimera can partially complement sgn3 Casparian strip formation phenotypes, suggesting that GSO1/SGN3 receptor activation is also mediated by SERK proteins. Collectively, our protein engineering approach may be used to elucidate the physiological functions of orphan LRR-RKs and to identify their receptor activation mechanism in single transgenic lines.

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