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Association of TRPV1 and TLR4 through the TIR domain potentiates TRPV1 activity by blocking activation-induced desensitization.
- Source :
-
Molecular Pain . 11/22/2018, Vol. 14, p1-10. 10p. - Publication Year :
- 2018
-
Abstract
- Background: We have previously reported that histamine-induced pruritus was attenuated in toll-like receptor 4 (TLR4) knockout mice due to decreased transient receptor potential V1 (TRPV1) sensitivity. Our results implied that TLR4 potentiated TRPV1 activation in sensory neurons; however, the molecular mechanism has yet to be elucidated. In this study, we investigated the molecular mechanisms of TLR4-mediated TRPV1 potentiation using TLR4-deficient sensory neurons and a heterologous expression system. Methods: Primary sensory neurons were obtained from wild-type or TLR4 knockout mice, and HEK293T cells expressing TRPV1 and TLR4 were prepared by transient transfection. TRPV1 activity was analyzed by calcium imaging, fluorophotometry, and patch-clamp recording. Subcellular protein distribution was tested by immunocytochemistry and cell surface biotinylation assay. Protein interaction was assessed by western blot and immunoprecipitation assay. Results: Direct association between TRPV1 and TLR4 was detected in HEK293T cells upon heterologous TRPV1 and TLR4 expression. In an immunoprecipitation assay using TLR4-deletion mutants and soluble toll/interleukin-1 receptor (TIR) protein, the cytoplasmic TIR domain of TLR4 was required for TLR4-TRPV1 association and TRPV1 potentiation. In TLR4-deficient sensory neurons, the activation-induced desensitization of TRPV1 increased, accompanied by enhanced TRPV1 clearance from the cell membrane upon activation compared to wild-type neurons. In addition, heterologous TLR4 expression inhibited activation-induced TRPV1 endocytosis and lysosomal degradation in HEK293T cells. Conclusion: Our data show that direct association between TRPV1 and TLR4 through the TIR domain enhances TRPV1 activity by blocking activation-induced TRPV1 desensitization. [ABSTRACT FROM AUTHOR]
- Subjects :
- *ITCHING
*HISTAMINE
*TRP channels
*SENSORY neurons
*FLUOROPHOTOMETRY
Subjects
Details
- Language :
- English
- ISSN :
- 17448069
- Volume :
- 14
- Database :
- Academic Search Index
- Journal :
- Molecular Pain
- Publication Type :
- Academic Journal
- Accession number :
- 133152131
- Full Text :
- https://doi.org/10.1177/1744806918812636