Molecular mechanisms regulating CD 13‐mediated adhesion

M Ghosh, C Gerber, MM Rahman, KM Vernier… - …, 2014 - Wiley Online Library
M Ghosh, C Gerber, MM Rahman, KM Vernier, FE Pereira, J Subramani, LA Caromile
Immunology, 2014Wiley Online Library
CD 13/Aminopeptidase N is a transmembrane metalloproteinase that is expressed in many
tissues where it regulates various cellular functions. In inflammation, CD 13 is expressed on
myeloid cells, is up‐regulated on endothelial cells at sites of inflammation and mediates
monocyte/endothelial adhesion by homotypic interactions. In animal models the lack of CD
13 alters the profiles of infiltrating inflammatory cells at sites of ischaemic injury. Here, we
found that CD 13 expression is enriched specifically on the pro‐inflammatory subset of …
Summary
CD13/Aminopeptidase N is a transmembrane metalloproteinase that is expressed in many tissues where it regulates various cellular functions. In inflammation, CD13 is expressed on myeloid cells, is up‐regulated on endothelial cells at sites of inflammation and mediates monocyte/endothelial adhesion by homotypic interactions. In animal models the lack of CD13 alters the profiles of infiltrating inflammatory cells at sites of ischaemic injury. Here, we found that CD13 expression is enriched specifically on the pro‐inflammatory subset of monocytes, suggesting that CD13 may regulate trafficking and function of specific subsets of immune cells. To further dissect the mechanisms regulating CD13‐dependent trafficking we used the murine model of thioglycollate‐induced sterile peritonitis. Peritoneal monocytes, macrophages and dendritic cells were significantly decreased in inflammatory exudates from global CD13KO animals when compared with wild‐type controls. Furthermore, adoptive transfer of wild‐type and CD13KO primary myeloid cells, or wild‐type myeloid cells pre‐treated with CD13‐blocking antibodies into thioglycollate‐challenged wild‐type recipients demonstrated fewer CD13KO or treated cells in the lavage, suggesting that CD13 expression confers a competitive advantage in trafficking. Similarly, both wild‐type and CD13KO cells were reduced in infiltrates in CD13KO recipients, confirming that both monocytic and endothelial CD13 contribute to trafficking. Finally, murine monocyte cell lines expressing mouse/human chimeric CD13 molecules demonstrated that the C‐terminal domain of the protein mediates CD13 adhesion. Therefore, this work verifies that the altered inflammatory trafficking in CD13KO mice is the result of aberrant myeloid cell subset trafficking and further defines the molecular mechanisms underlying this regulation.
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