Immobilized chemokine fields and soluble chemokine gradients

cooperatively shape migration patterns of dendritic cells

Kathrin Schumann, Tim Lämmermann,Markus Bruckner,Daniel F. Legler, Julien Polleux, Joachim P. Spatz,Gerold Schuler, Reinhold Förster, Manfred B. Lutz, Lydia Sorokin, and Michael Sixt

Marius DöringZIB Class of 2009paper presentation 14.02.2011

Introduction

Chemokines:

• chemotactic cytokines– Small 8-10 kDa– classification according to positioning of 4 cysteine residues– signal via GPCR

• central orchestrators of hematopoetic system– Homing & positioning of lymphocytes in secondary lymphoid organs– Integrin activation– Polarization of actomyosin cytoskeleton

Introduction

Cell movement

on a surface: • Haptokinesis vs haptotaxis

adhesion independent:• chemokinesis va chemotaxis

Chemotaxis Haptokinesis

Haptotaxis biased by chemotactic gradient

Model system:Migration of DC depentent on CCR7 and its ligands CCL19/21

CCL19:mostly soluble due to truncated N-terminus

CCL21:binds to heperansulfate

Adopted from Rot et. al 2008

Results

LPS matured DC on unfixed cryosection of inguinal LN

DCs mirgate on LN into the T cell area along the interfollicular region

Results

DCs mirgate on LN in a CCR7 & CCR7 ligand dependent manner along a soluble gradient

Results

Immobilized CCL21 triggers:1)rapid spreading2)random migration3)release of soluble factor to attract other DCs

Results

DCs generate a truncated CCL21 upon encouter of CCL21 by cleavage from the C terminus

Results

Haptokinesis (spreading, polarization & migration) of DCs is induced by interaction of CCR7 and immobilized ß2 integrin

Results

Chemotactic and adhesive signals compete & those two forces lead to a directed haptotactic movement

Conclusion• Mature DCs activated ß2 integrin and cytoskeletal

polarization upon contact with immonilized CCL21 haptokinetic movement

• CCL19 did not induce adhesion but cellular polarization chemotactic movement

• Combination of CCL19/21 lead to directionally biased haptokinetic migration

• During their mirgation DCs generated a truncated version of CCL21 – Immobiliezd CCL21 dictates the PW– Soluble factors direction of migration

The End

!!!Thank you for your attention!!!??Question??

Introduction