151. TRPV1 mediates capsaicin-stimulated metabolic activity but not cell death or inhibition of interleukin-1β release in human THP-1 monocytes
- Author
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Dominic P. Geraghty, Januttha Yingchoncharoen, Dale Kunde, and Saša Jurković
- Subjects
0301 basic medicine ,Programmed cell death ,THP-1 Cells ,medicine.medical_treatment ,Interleukin-1beta ,Cell ,TRPV1 ,TRPV Cation Channels ,Pharmacology ,Toxicology ,Monocytes ,Vanilloids ,Cell Line ,03 medical and health sciences ,chemistry.chemical_compound ,Immune system ,medicine ,Humans ,THP1 cell line ,Cell Death ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,Chemistry ,030104 developmental biology ,Cytokine ,medicine.anatomical_structure ,Capsaicin ,lipids (amino acids, peptides, and proteins) ,Diterpenes - Abstract
Human monocytes and dendritic cells express transient receptor potential vanilloid 1 (TRPV1) which may play a role in mediating the inflammatory, immune and cancer surveillance responses of these cells. The aim of the present study was to investigate TRPV1 expression and function in THP-1 monocytic cells. RT-PCR and Western blot were used to detect TRPV1. The metabolic activity and viability of THP-1 cells following exposure to vanilloids was assessed using resorufin production from rezazurin. Cytokine release was measured using ELISA. TRPV1 was expressed in cultured THP-1 monocytic cells and naïve monocytes. Lower concentrations (250 μM) of capsaicin, but not other putative TRPV1 agonists, were shown to stimulate cell metabolic activity, whereas at concentrations250 μM, all agonists decreased metabolic activity. Capsaicin-stimulated THP-1 metabolic activity was blocked by the TRPV1 antagonist, 5-iodo-resiniferatoxin (5'-IRTX), whereas the decline in resorufin production by THP-1 cells at higher capsaicin concentrations (due to cell death), was not affected by 5'-IRTX. Finally, capsaicin (≤125 μM) significantly increased lipopolysaccharide-stimulated IL-6 and TNF-α release from THP-1 cells, whereas phytohaemagglutinin-stimulated IL-1β, TNF-α, MCP-1 and IL-6 release were concentration-dependently inhibited by capsaicin. Modulation of IL-1β release was not TRPV1 mediated. Overall, these results show that functional TRPV1 channels are present in naïve monocytes and THP-1 cells, and when activated, increase cell metabolic activity. In addition, capsaicin modifies cytokine release from THP-1 cells and induces cell death, most likely by a mechanism that is independent of TRPV1 activation.
- Published
- 2018