Granzyme K initiates IL-6 and IL-8 release from epithelial cells by activating protease-activated receptor 2
Fig 2
Cleavage of PAR2 by granzyme K does not induce Ca2+ flux.
KNRK cells expressing human PAR2 (KNRK-PAR2) were treated with the indicated proteases. (A) Fluctuations in intracellular calcium were measured by change in Fura2 fluorescence spectra following treatment. Cells were treated with trypsin, granzyme K (GzmK) or AEBSF-inhibited GzmK (GzmK-AI) or buffer at the indicated time (arrow) and fluorescence measured over a 4 min window. (B) Total response, defined as the area under the curve was determined and standardised to the trypsin response. (C) Cells were pre-treated with GzmK, AEBSF-inhibited GzmK (GzmK-AI), or buffer for 30 min then treated with trypsin and the calcium flux followed by Fura2 fluorescence. (D) Total response, defined as the area under the curve was determined and standardised to the pre-treatment with vehicle response. *, p < 0.05; **, p < 0.01; ns, p > 0.05.