1. The human cytokine TSLP triggers a cell-autonomous dendritic cell migration in confined environments
by Maria-Isabel Fernandez, Mélina L. Heuzé, Carolina Martinez-Cingolani, Elisabetta Volpe, Marie-Helene Donnadieu, Matthieu Piel, Bernhard Homey, Ana-Maria Lennon-Duménil, and Vassili Soumelis
Blood
Volume 118(14):
October 6, 2011
©2011 by American Society of Hematology

2. TSLP induces chemokinesis of resting DCs in a cell-autonomous manner.
TSLP induces chemokinesis of resting DCs in a cell-autonomous manner. (A) Purified blood DCs were precultured in medium (untreated), TSLP, influenza virus (Flu), LPS, or GM-CSF. After 24 hours, cells were washed, counted, and seeded in equal numbers in the upper chamber of an uncoated transwell system in the absence of chemotactic factors. After 6 hours, DCs migrating into the lower chamber were harvested and counted. Data are represented as percentage of input DCs. In the positive control, CCL20 was used in the lower chamber during migration as a chemotactic factor. Data are mean ± SD; n = 7. *P < .05 vs untreated. (B) Primary blood DCs were precultured in medium, TSLP, TNF, influenza virus (Flu), LPS, or GM-CSF. After 24 hours, cells were washed, counted, and seeded in equal numbers in the upper chamber of a collagen-coated transwell system in the absence of chemotactic factors. After 6 hours, DC migration was quantified. Data are represented as percentage of input DCs. In the positive control, CCL20 was added in the lower well. Data are mean ± SD; n = 5. *P < .05 vs untreated.
Maria-Isabel Fernandez et al. Blood 2011;118:
©2011 by American Society of Hematology

3. TSLP induces polarization of the DC cytoskeleton.
TSLP induces polarization of the DC cytoskeleton. (A) DCs on poly-lysine–coated coverslips were cultured in medium (untreated), influenza virus (Flu), LPS, or TSLP. Cells were stained for actin (red) and DAPI (blue) and observed under a fluorescence microscopy. Podosomes appeared as round actin-stained formations. Actin skeleton was reorganized in a polarized manner in TSLP-DCs. Data are from one representative of 5 independent experiments. (B) After 24 hours of culture, DCs with a polarized actin skeleton were quantified. Results are represented as percentage of total DCs. Data are mean ± SD; n = 5. *P < .05 vs untreated. +P < .05 vs TSLP. (C) After 24 hours of culture, DCs were stained with an anti–α-tubulin mAb (green) and DAPI (blue). TSLP-DCs showed a reorganization of the microtubules. Data are from 1 representative of 5 independent experiments.
Maria-Isabel Fernandez et al. Blood 2011;118:
©2011 by American Society of Hematology

4. TSLP induces redistribution and colocalization of actin and phospho-myosin II light chain.
TSLP induces redistribution and colocalization of actin and phospho-myosin II light chain. (A) After 24 hours of culture, TSLP-DCs were stained for myosin II (green), actin (red), and DAPI (blue). TSLP-DCs acquired a polarized morphology, and actin and myosin filaments largely colocalized. Data are from 1 representative of 3 independent experiments. (B) DCs on poly-lysine–coated coverslips were cultured in medium, TSLP, or LPS for 20 hours. Cells were stained for F-actin (red) and pMLC9 (green). Images were acquired as z-series, deconvoluted, and reconstructed as a maximum-intensity projection of all the planes. (C) Quantification of the mean percentage of pMLC area colocalized with F-actin area. For each cell, the percentage is a mean of all the planes. Data are mean ± SEM of 2 independent experiments; n = 20. ***P < .005.
Maria-Isabel Fernandez et al. Blood 2011;118:
©2011 by American Society of Hematology

5. Myosin II is required for TSLP-induced polarization and motility.
Myosin II is required for TSLP-induced polarization and motility. (A) After 24 hours of culture in the absence or presence of blebbistatin (50μM), TSLP-DCs were stained for myosin II (green), actin (red), and DAPI (blue). Blebbistatin inhibited TSLP-induced cytoskeleton rearrangements with a loss of cell polarization. Data are from 1 representative of 3 independent experiments. (B) DCs were cultured as described in Figure 1A, in the absence or presence of blebbistatin. An increased migration (6 hours) was observed after TSLP pretreatment, which was significantly decreased in the presence of blebbistatin (50μM). Each dot represents cell counts of individual experiments and bars represent the mean. *P < .05.
Maria-Isabel Fernandez et al. Blood 2011;118:
©2011 by American Society of Hematology

6. TSLP promotes DC migration in the confined environment of microchannels.
TSLP promotes DC migration in the confined environment of microchannels. (A) After 20 hours of culture in medium or TSLP, DCs were added in the starting chamber of the microchannel system. They were allowed to spontaneously enter the fibronectin-coated 4-μm-wide channels, and phase-contrast images were recorded. The number of cells entering the channels dramatically increased after TSLP activation of DCs (arrow indicates an individual cell inside a microchannel). (B) Representative kymograph of an untreated DC and a TSLP-DC generated by sequential pictures of a DC within a microchannel. We can see the untreated DC changing direction several times during the recording. Raw phase-contrast images were processed to analyze cell movement as described in “Kymograph extraction and instantaneous velocity.” (C) After 20 hours of culture, DCs were allowed to spontaneously enter the fibronectin-coated 4-μm-wide channels, and phase-contrast images were recorded. Changes of direction through the channels were quantified for individual cells. TSLP-DCs exhibited a more straight movement. Only 10% of TSLP-DCs show changes in direction inside the microchannels. (D) Kymographs obtained in panel C were processed and analyzed to extract instantaneous speed of individual cells. The distributions of median and maximal speed of DCs precultured in control medium (left panels) or with TSLP (right panels) are not significantly different (P > .05). Data are from one representative of 3 independent experiments.
Maria-Isabel Fernandez et al. Blood 2011;118:
©2011 by American Society of Hematology

7. Myosin II-ATPase activity is essential for DC confined migration.
Myosin II-ATPase activity is essential for DC confined migration. (A) After a pretreatment of 20 hours with TSLP in the absence or presence of blebbistatin (50μM) or a mix of ML7/Y27632 (10μM/10μM), DCs were loaded in the entry chamber of the channels. The number of DCs entering the channels during a 12-hour time-lapse movie was quantified. TSLP induced a 4-fold increase in the capacity of DCs to enter microchannels compared with control. Blebbistatin and ML7Y27632 significantly inhibited TSLP-induced migration. Data are mean ± SD; n = 3. **P < .01. ***P < (B) After 20 hours of culture in the absence or presence of blebbistatin (50μM), DCs were loaded in the entry chamber and allowed to spontaneously enter in the channels. Phase-contrast images were recorded. Kymographs were processed and analyzed to extract instantaneous speed of individual cells. Distribution of the median speed of DCs precultured in TSLP in the absence or presence of blebbistatin is significantly different (P < .05). Data are from 1 representative of 2 independent experiments.
Maria-Isabel Fernandez et al. Blood 2011;118:
©2011 by American Society of Hematology