Vanilloid Receptor 1 Agonists, Capsaicin and Resiniferatoxin, Enhance MHC Class I-restricted Viral Antigen Presentation in Virus-infected Dendritic Cells

DCs, like the sensory neurons, express vanilloid receptor 1 (VR1). Here we demonstrate that the VR1 agonists, capsaicin (CP) and resiniferatoxin (RTX), enhance antiviral CTL responses by increasing MHC class I-restricted viral antigen presentation in dendritic cells (DCs). Bone marrow-derived DCs (BM-DCs) were infected with a recombinant vaccinia virus (VV) expressing OVA (VV-OVA), and then treated with CP or RTX. Both CP and RTX increased MHC class I-restricted presentation of virus-encoded endogenous OVA in BM-DCs. Oral administration of CP or RTX significantly increased MHC class I-restricted OVA presentation by splenic and lymph node DCs in VV-OVA-infected mice, as assessed by directly measuring OVA peptide SIINFEKL-Kb complexes on the cell surface and by performing functional assays using OVA-specific CD8 T cells. Accordingly, oral administration of CP or RTX elicited potent OVA-specific CTL activity in VV-OVA-infected mice. The results from this study demonstrate that VR1 agonists enhance anti-viral CTL responses, as well as a neuro-immune connection in anti-viral immune responses.

Construction of VR1 siRNA expression vectors and their silencing effects in the DRG neurons of rats / 中国药理学通报

Aim To study the function of VR1 in chronic pain, to construct VR1 siRNA expression vectors and to study their silencing effect in the DRG neurons of rats were detected.Methods The hairpin sequences of siRNAs targeting VR1 gene of rat were designed, and two pairs of oligonucleotide sequence were synthesized. The annealed oligonucleotide fragments were cloned into linearized pRNAT-U6.2/Lenti expression vector and identified by PCR and DNA sequencing.Then, they were co-transfected by lipofectamine into 293T cells.The silencing effects of the lentivector-mediated VR1 siRNAs on the expression of VR1 mRNA were determined by RT-PCR after intrathecal injection in rats.Results DNA sequencing showed that the oligonucleotide fragments were correctly cloned into linearized pRNAT-U6.2/Lenti expression vector and the expression of VR1 mRNA in L4-L6 DRG neurons was inhibited significantly by pRNAT-U6.2/Lenti-siVR1 after intrathecal injection in rats.Conclusion The lentivector-mediated siRNAs are successfully constructed and they inhibit the expression of VR1 mRNA in the DRG neurons of rats, which may provide a potential tool for the further study and treatment of chronic pain.

Distribution of Purinergic Receptor and Vanilloid Receptor Participating in Micturition and Reciprocal Relationship between Them / 대한해부학회지

Two of the synaptic receptors involved in the regulation of micturition, P2X(3) receptor, which is operated by ATP, and vanilloid receptor 1 (VR1), which is operated by capsaicin, are regarded as newcomers. To investigate the possibility that these receptors act as therapeutic targets for treatment of an overactive bladder, we investigated their distribution and reciprocal relationship. Eight-week-old Sprague Dawley rats were injected with retrograde nerve tracer within the bladder wall, and 15 rats were injected with 0.5% acetic acid inside the bladder. After a week, the animals were killed, and their dorsal root ganglia (DRG) at the levels of L6 and S1 were harvested. Immunohistochemistry or Western blot analysis of P2X(3) and VR1 were performed on the DRG. The DRG neurons with afferent fibers from the bladder had increased expression of VR1 and downregulated P2X(3) receptors. The P2X(3) receptor and VR1 seemed to account for the important parts of the hypersensitivity of the inflammatory bladder. We conclude that the simultaneous modulations of both P2X(3) receptor and VR1 may have a synergic effect on the treatment of overactive bladder and may produce greater response rates.

The VR1-Positive Primary Afferent-Mediated Expression of pERK in the Lumbosacral Neurons in Response to Mechanical and Chemical Stimulation of the Urinary Bladder in Rats

OBJECTIVE: This study characterized the neurons in the lumbosacral cord that express phospho ERK (pERK) after distension or irritation of the bladder, and their relation to the vanilloid receptor 1 (VR1) positive primary afferents. METHODS: Mechanical distension and chemical irritation of the bladder were induced by intravesical injection of the saline and mustard oil, respectively. Spinal neurons expressing pERK and the primary afferent fibers were characterized using multiple immunofluorescence for neurokinin 1 (NK1), neuronal nitric oxide synthetase (nNOS) and VR1. RESULTS: Neurons in lamina I, medial dorsal horn (MDH), dorsal gray commissure (DGC) and sacral parasympathetic nucleus (SPN) were immunoreactive for pERK after either mechanical or chemical stimulation. The majority of pERK positive cells were positive for NK1 in lamina I and SPN, but not in the DGC. Most of pERK positive cells are not stained for nNOS except in a small population of the cells in the SPN and DGC. Contacts between perikarya and dendrites of pERK-positive cells and terminals of primary afferents expressing VR1 were identified in lamina I, lateral collateral path (LCP) and SPN. CONCLUSION: In this study, the lumbosacral neurons activated by mechanical and chemical stimulation of the urinary bladder were identified with expression of the pERK, and also provided the evidence that VR1-positive primary afferents may mediate the activation of these neurons.

Anatomical Characterization of Vanilloid Receptor 1 (VR1)-positive Primary Afferents in Lower Lumbar Cord in the Rat / 대한해부학회지

Primary afferents sensitive to capsaicin and noxious heat express vanilloid receptor 1(VR1) in both their peripheral and central fibers and terminals. We used multiple immunofluorescence and confocal microscopy to characterize their pattern of termination in rat spinal cord, colocalization of neurochemical markers of primary afferents and other presynaptic receptors. VR1-positive unmyelinated fibers mainly terminate in lamina I, where they co-stain for CGRP, and to a limited extent for SP, and in lamina II, especially its medial half, where they co-stain for IB4. VR1 positive thin myelinated fibers terminate in lamina I and co-stain for the neurochemical tracer CTB, injected in the sciatic nerve. As revealed by simultaneous staining for the synaptic marker synaptophysin, VR1-positive terminals are abundant in lamina I and sparse in lamina II. In L6-S1 spinal cord, VR1-positive fibers and terminals were abundant in Lissauer's tract, lamina I-V, medial collateral path to lamina X, and lateral collateral path to sacral parasympathetic nucleus. Most of VR1 positive fibers in Lissuer's tract and LCP are colocalized with SP. In conclusion, it is suggested that VR1 positive fibers in spinal cord are both peptidergic and non-peptidergic, IB4 positive fibers, mediating both somatic and visceral sensations, and that peptidergic VR1 positive fibers are mainly related with visceral sense.

Vanilloid Receptor Type-1 Immunoreactivities in the Mouse Myenteric Plexus: Immunohistochemical and Electrophysiological Study / 체질인류학회지

The vanilloid receptor type-1 (VR1) is a nonselective cation channel activated by capsaicin and can be act as mediator of chemical and physical stimuli that elicit pain. The presence of VR1 in the dorsal root, trigeminal and nodose ganglia has been firmly established, but it unclear in the mouse intestinal wall. The distribution of VR1 receptors in mouse afferent neurons innervating the intestinal tract was investigated by immunohistochemistry. Also small and large intestines were dual-labelled with antibody for VR1 and marker for interstitial cells of Cajal (c-kit). VR1-immunopositive cells were localized on fine fibers in myenteric plexus and expressed weakly myenteric ganglia. The majority of VR1-immunopositive fibers are not colocalized with or apposed to c-kit positive interstitial cells of Cajal. Also electrophysiologically capsaicin had no effect on cultured interstitial cells of Cajal. It is concluded that VR1-immunoreactive intestinal nerves are mainly distributed in myenteric plexus of murine intestinal wall, and vanillod may be not directly related to interstitial cells of Cajal in regulation of intestinal motility.

Vanilloid Receptor Type-1 Immunoreactivities in the Mouse Myenteric Plexus: Immunohistochemical and Electrophysiological Study / 체질인류학회지

The vanilloid receptor type-1 (VR1) is a nonselective cation channel activated by capsaicin and can be act as mediator of chemical and physical stimuli that elicit pain. The presence of VR1 in the dorsal root, trigeminal and nodose ganglia has been firmly established, but it unclear in the mouse intestinal wall. The distribution of VR1 receptors in mouse afferent neurons innervating the intestinal tract was investigated by immunohistochemistry. Also small and large intestines were dual-labelled with antibody for VR1 and marker for interstitial cells of Cajal (c-kit). VR1-immunopositive cells were localized on fine fibers in myenteric plexus and expressed weakly myenteric ganglia. The majority of VR1-immunopositive fibers are not colocalized with or apposed to c-kit positive interstitial cells of Cajal. Also electrophysiologically capsaicin had no effect on cultured interstitial cells of Cajal. It is concluded that VR1-immunoreactive intestinal nerves are mainly distributed in myenteric plexus of murine intestinal wall, and vanillod may be not directly related to interstitial cells of Cajal in regulation of intestinal motility.

VR1 and neuropathic pain / 中国药理学通报

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