CXCR7 prevents excessive CXCL12-mediated downregulation of CXCR4 in migrating cortical interneurons

Philipp Abe, Wiebke Mueller, Dagmar Schutz, Fabienne Mackay-Fisson, Marcus Thelen, Penglie Zhang, Ralf Stumm

Research output: Contribution to journalArticleResearchpeer-review

53 Citations (Scopus)

Abstract

The CXCL12/CXCR4 signaling pathway is involved in the development of numerous neuronal and non-neuronal structures. Recent work established that the atypical second CXCL12 receptor, CXCR7, is essential for the proper migration of interneuron precursors in the developing cerebral cortex. Two CXCR7-mediated functions were proposed in this process: direct modulation of ?-arrestin-mediated signaling cascades and CXCL12 scavenging to regulate local chemokine availability and ensure responsiveness of the CXCL12/CXCR4 pathway in interneurons. Neither of these functions has been proven in the embryonic brain. Here, we demonstrate that migrating interneurons efficiently sequester CXCL12 through CXCR7. CXCR7 ablation causes excessive phosphorylation and downregulation of CXCR4 throughout the cortex in mice expressing CXCL12, but not in CXCL12-deficient animals. Cxcl12-/- mice lack activated CXCR4 in embryonic brain lysates and display a similar interneuron positioning defect as Cxcr4-/-, Cxcr7-/- and Cxcl12-/-;Cxcr7-/- animals. Thus, CXCL12 is the only CXCR4-activating ligand in the embryonic brain and deletion of one of the CXCL12 receptors is sufficient to generate a migration phenotype that corresponds to the CXCL12-deficient pathway. Our findings imply that interfering with the CXCL12-scavenging activity of CXCR7 causes loss of CXCR4 function as a consequence of excessive CXCL12-mediated CXCR4 activation and degradation.
Original languageEnglish
Pages (from-to)1857 - 1863
Number of pages7
JournalDevelopment
Volume141
Issue number9
DOIs
Publication statusPublished - 2014

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