Fibroblast-specific protein 1 identifies an inflammatory subpopulation of macrophages in the liver

Christoph H. Österreicher, Melitta Penz-Österreicher, Sergei I. Grivennikov, Monica Guma, Ekaterina K. Koltsova, Christian Datz, Roman Sasik, Gary Hardiman, Michael Karin, David A. Brenner

Research output: Contribution to journalArticlepeer-review

227 Citations (Scopus)


Cirrhosis is the end result of chronic liver disease. Hepatic stellate cells (HSC) are believed to be the major source of collagen-producing myofibroblasts in cirrhotic livers. Portal fibroblasts, bone marrow-derived cells, and epithelial to mesenchymal transition (EMT) might also contribute to the myofibroblast population in damaged livers. Fibroblast-specific protein 1 (FSP1, also called S100A4) is considered a marker of fibroblasts in different organs undergoing tissue remodeling and is used to identify fibroblasts derived from EMT in several organs including the liver. The aim of this study was to characterize FSP1-positive cells in human and experimental liver disease. FSP1-positive cells were increased in human and mouse experimental liver injury including liver cancer. However, FSP1 was not expressed by HSC or type I collagen-producing fibroblasts. Likewise, FSP1-positive cells did not express classical myofibroblast markers, including αSMA and desmin, and were not myofibroblast precursors in injured livers as evaluated by genetic lineage tracing experiments. Surprisingly, FSP1-positive cells expressed F4/80 and other markers of the myeloid-monocytic lineage as evaluated by double immunofluorescence staining, cell fate tracking, flow cytometry, and transcriptional profiling. Similar results were obtained for bone marrow-derived and peritoneal macrophages. FSP1-positive cells were characterized by increased expression of COX2, osteopontin, inflammatory cytokines, and chemokines but reduced expression of MMP3 and TIMP3 compared with Kupffer cells/macrophages. These findings suggest that FSP1 is a marker of a specific subset of inflammatory macrophages in liver injury, fibrosis, and cancer.

Original languageEnglish
Pages (from-to)308-313
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number1
Publication statusPublished - 04 Jan 2011
Externally publishedYes


  • Tumor microenvironment

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Fibroblast-specific protein 1 identifies an inflammatory subpopulation of macrophages in the liver'. Together they form a unique fingerprint.

Cite this