Cellular plasticity of inflammatory myeloid cells in the peritoneal foreign body response.
Implantation of sterile foreign objects in the peritoneal cavity of an animal initiates an inflammatory response and results in encapsulation of the objects by bone marrow-derived cells. Over time, a multilayered tissue capsule develops with abundant myofibroblasts embedded in extracellular matrix. The present study used the transgenic MacGreen mouse to characterize the time-dependent accumulation of monocyte subsets and neutrophilic granulocytes in the inflammatory infiltrate and within the tissue capsule by their differential expression of the csf1r-EGFP transgene, F4/80, and Ly6C. As the tissue capsule developed, enhanced green fluorescent protein-positive cells changed from rounded to spindle-shaped morphology and began to co-express the myofibroblast marker alpha-smooth muscle actin. Expression increased with time: at day 14, 11.13 +/- 0.67% of tissue capsule cells co-expressed these markers, compared with 50.77 +/- 12.85% of cells at day 28. The importance of monocyte/macrophages in tissue capsule development was confirmed by clodronate-encapsulated liposome removal, which resulted in almost complete abrogation of capsule development. These results confirm the importance of monocyte/macrophages in the tissue response to sterile foreign objects implanted in the peritoneal cavity. In addition, the in vivo plasticity of peritoneal macrophages and their ability to transdifferentiate from a myeloid to mesenchymal phenotype is demonstrated.
Mooney
Jane E
JE
Centre for Research in Vascular Biology, Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St. Lucia, QLD 4072, Australia.
Rolfe
Barbara E
BE
Osborne
Geoffrey W
GW
Sester
David P
DP
van Rooijen
Nico
N
Campbell
Gordon R
GR
Hume
David A
DA
Campbell
Julie H
JH
D000818:Animals; D002465:Cell Movement; D048430:Cell Shape; D054338:Cell Transdifferentiation; D005260:Female; D005347:Fibroblasts / Q000166:cytology; D005547:Foreign Bodies / Q000473:pathology; D005549:Foreign-Body Reaction / Q000473:pathology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D020007:Implants, Experimental; D008264:Macrophages / Q000166:cytology; D008297:Male; D051379:Mice; D022423:Myeloid Cells / Q000473:pathology*; D010529:Peritoneal Cavity / Q000473:pathology*; D010533:Peritoneal Lavage
C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins