TY - JOUR
T1 - Lack of specificity of fibroblast-specific protein 1 in cardiac remodeling and fibrosis
AU - Kong, Ping
AU - Christia, Panagiota
AU - Saxena, Amit
AU - Su, Ya
AU - Frangogiannis, Nikolaos G.
PY - 2013/11/1
Y1 - 2013/11/1
N2 - Understanding the role of fibroblasts in pathologic conditions is hampered by the absence of specific markers. Fibroblast-specific protein (FSP)1 has been suggested as a fibroblast-specific marker in normal and fibrotic tissues; FSP1 reporter mice and FSP1-Cre-driven gene deletion are considered reliable strategies to investigate fibroblast biology. Because fibroblasts are abundant in normal and injured mammalian hearts, we studied the identity of FSP1+ cells in the infarcted and remodeling myocardium using mice with green fluorescent protein (GFP) expression driven by the FSP1 promoter. Neonatal and adult mouse hearts had low numbers of FSP1+ cells. Myocardial infarction induced marked infiltration with FSP1-expressing cells that peaked after 72 h of reperfusion. Using flow cytometry, we identified 50% of FSP1+ cells as hematopoietic cells; many endothelial cells were also FSP1+. Increased infiltration with FSP1+ cells was also noted in the pressure-overloaded myocardium. Although some FSP1+ cells had fibroblast morphology, >30% were identified as hematopoietic cells, endothelial cells, or vascular smooth muscle cells. In contrast, periostin did not stain leukocytes or vascular cells but labeled spindle-shaped interstitial cells and, as a typical matricellular protein, was deposited in the matrix. CD11b+ myeloid cells sorted from the infarcted heart had higher FSP1 expression than corresponding CD11b-negative cells, highlighting the predominant expression by hematopoietic cells. FSP1 is not a specific marker for fibroblasts in cardiac remodeling and fibrosis.
AB - Understanding the role of fibroblasts in pathologic conditions is hampered by the absence of specific markers. Fibroblast-specific protein (FSP)1 has been suggested as a fibroblast-specific marker in normal and fibrotic tissues; FSP1 reporter mice and FSP1-Cre-driven gene deletion are considered reliable strategies to investigate fibroblast biology. Because fibroblasts are abundant in normal and injured mammalian hearts, we studied the identity of FSP1+ cells in the infarcted and remodeling myocardium using mice with green fluorescent protein (GFP) expression driven by the FSP1 promoter. Neonatal and adult mouse hearts had low numbers of FSP1+ cells. Myocardial infarction induced marked infiltration with FSP1-expressing cells that peaked after 72 h of reperfusion. Using flow cytometry, we identified 50% of FSP1+ cells as hematopoietic cells; many endothelial cells were also FSP1+. Increased infiltration with FSP1+ cells was also noted in the pressure-overloaded myocardium. Although some FSP1+ cells had fibroblast morphology, >30% were identified as hematopoietic cells, endothelial cells, or vascular smooth muscle cells. In contrast, periostin did not stain leukocytes or vascular cells but labeled spindle-shaped interstitial cells and, as a typical matricellular protein, was deposited in the matrix. CD11b+ myeloid cells sorted from the infarcted heart had higher FSP1 expression than corresponding CD11b-negative cells, highlighting the predominant expression by hematopoietic cells. FSP1 is not a specific marker for fibroblasts in cardiac remodeling and fibrosis.
KW - Cardiac fibrosis
KW - Cardiac remodeling
KW - Fibroblast
KW - Myocardial infarction
KW - Periostin
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U2 - 10.1152/ajpheart.00395.2013
DO - 10.1152/ajpheart.00395.2013
M3 - Article
C2 - 23997102
AN - SCOPUS:84887004755
SN - 0363-6135
VL - 305
SP - H1363-H1372
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 9
ER -