Evidence that fibroblasts derive from epithelium during tissue fibrosis

Interstitial fibroblasts are principal effector cells of organ fibrosis in kidneys, lungs, and liver. While some view fibroblasts in adult tissues as nothing more than primitive mesenchymal cells surviving embryologic development, they differ from mesenchymal cells in their unique expression of fibroblast-specific protein-1 (FSP1). This difference raises questions about their origin. Using bone marrow chimeras and transgenic reporter mice, we show here that interstitial kidney fibroblasts derive from two sources. A small number of FSP1+, CD34– fibroblasts migrate to normal interstitial spaces from bone marrow. More surprisingly, however, FSP1+ fibroblasts also arise in large numbers by local…

• AS
  American Society of Nephrology
• VU
  Vanderbilt University
• NI
  National Institutes of Health