Different activation signals induce distinct mast cell degranulation strategies
Nicolas Gaudenzio, … , Eric Espinosa, Stephen J. Galli
Nicolas Gaudenzio, … , Eric Espinosa, Stephen J. Galli
Published September 19, 2016
Citation Information: J Clin Invest. 2016;126(10):3981-3998. https://doi.org/10.1172/JCI85538.
View: Text | PDF
Research Article Immunology Inflammation

Different activation signals induce distinct mast cell degranulation strategies

Abstract

Mast cells (MCs) influence intercellular communication during inflammation by secreting cytoplasmic granules that contain diverse mediators. Here, we have demonstrated that MCs decode different activation stimuli into spatially and temporally distinct patterns of granule secretion. Certain signals, including substance P, the complement anaphylatoxins C3a and C5a, and endothelin 1, induced human MCs rapidly to secrete small and relatively spherical granule structures, a pattern consistent with the secretion of individual granules. Conversely, activating MCs with anti-IgE increased the time partition between signaling and secretion, which was associated with a period of sustained elevation of intracellular calcium and formation of larger and more heterogeneously shaped granule structures that underwent prolonged exteriorization. Pharmacological inhibition of IKK-β during IgE-dependent stimulation strongly reduced the time partition between signaling and secretion, inhibited SNAP23/STX4 complex formation, and switched the degranulation pattern into one that resembled degranulation induced by substance P. IgE-dependent and substance P–dependent activation in vivo also induced different patterns of mouse MC degranulation that were associated with distinct local and systemic pathophysiological responses. These findings show that cytoplasmic granule secretion from MCs that occurs in response to different activating stimuli can exhibit distinct dynamics and features that are associated with distinct patterns of MC-dependent inflammation.

Authors

Nicolas Gaudenzio, Riccardo Sibilano, Thomas Marichal, Philipp Starkl, Laurent L. Reber, Nicolas Cenac, Benjamin D. McNeil, Xinzhong Dong, Joseph D. Hernandez, Ronit Sagi-Eisenberg, Ilan Hammel, Axel Roers, Salvatore Valitutti, Mindy Tsai, Eric Espinosa, Stephen J. Galli

×

Figure 5

The features of exteriorized human MC granule structures can vary depending on the stimulus.

Options: View larger image (or click on image) Download as PowerPoint
The features of exteriorized human MC granule structures can vary depend...
(A) Photographs of PBCMCs activated with anti-IgE (upper panels) or SP (lower panels). From left to right: Av.SRho (red) merged with differential interference contrast (DIC; gray); Av.SRho (red); isosurface modeling (red) of Av.SRho; modeled granule structures; modeled volume calculation. (B) Total accumulated volume of budding granule structures (i.e., total amount of externalized Av.SRho+ granule volume per MC) in cubic micrometers. (C) Total numbers of exocytosed Av.SRho+ granule structures. (D) Modeled volumes of budding granule structures (in cubic micrometers, assessing the size of granule structures still attached to the MC surface) per single MC during the first minute after the start of degranulation, following anti-IgE (blue) or SP (pink) stimulation. (E) 3D photographs of single PBCMCs embedded in a matrix gel, 30 minutes after exposure to medium (no stimulation, upper panels), anti-IgE (middle panels), or SP (lower panels). Panels, left to right: Av.SRho (red) merged with Fluo-4 (green); isosurface modeling of Av.SRho (red) and Fluo-4 (green); virtual isolation of released granule structures (structures are pseudocolored based on their volume). (F) Modeled volumes (in cubic micrometers, assessing granule structures not attached to the MC surface). (G) Modeled sphericity indices (from 0 to 1, 1 being a perfect sphere). Data shown in F and G were obtained 30 minutes after the beginning of mast cell stimulation. (B and C) Mean ± SEM; 2-way ANOVA. (D, F, and G) Left panel: each dot represents 1 individual granule structure analyzed; right panel: mean ± SEM of the data shown in the left panel. Data are from more than 200 granule structures analyzed per condition. Two-tailed, unpaired t test; *P < 0.05; ***P < 0.001; ****P < 0.0001. Data are from 3 independent experiments, each of them performed with PBCMCs from a different single donor, each of which gave similar results. Scale bars: 5 μm.