Selective migration of alpha-smooth muscle actin-positive myofibroblasts toward fibronectin in the Boyden's blindwell chamber.
1. In order to address the hypothesis that migrating fibroblasts have a different phenotype, human fetal lung fibroblasts (HFL-1) cells were evaluated in the Boyden blindwell chamber migration assay followed by immunoelectron microscopy. 2. HFL-1 cells were placed on nucleopore filters and incubated for 2 h using purified human plasma fibronectin (pFn) as a chemoattractant. Filters were then processed for immunoelectron microscopy using antibodies for alpha-smooth muscle (alpha-SM) actin as a marker for myofibroblasts, cellular fibronectin (cFn) and VLA-5. 3. Cells which had migrated to the bottom side of the filter were more likely to express alpha-SM actin, 29.1 +/- 3.4% of cells, compared with cells which did not migrate through the filter, 12.4 +/- 1.3% (P < 0.05). The total proportion of alpha-SM-actin-positive cells located on both sides of the filter showed no difference between those which had migrated toward pFn and controls (17.7 +/- 1.0% compared with 20.2 +/- 2.5%). 4. cFn-positive cells showed minimal differences compared with control cells, while perinuclear and endoplasmic reticulum staining of VLA-5 was observed only in the cells treated with pFn. 5. The results show that HFL-1 cells are heterogenous for alpha-SM actin expression. Short-term incubation with pFn did not change the proportion of alpha-SM-actin-positive HFL-1 cells. Cells which migrate, however, are enriched for alpha-SM actin expression. pFn-induced fibroblast chemotaxis can selectively recruit myofibroblasts with increased alpha-SM actin expression, a feature which may contribute to the altered population of cells at sites of fibrosis.
Kawamoto
M
M
Department of Pathology, Nippon Medical School, Tokyo, Japan.
Matsunami
T
T
Ertl
R F
RF
Fukuda
Y
Y
Ogawa
M
M
Spurzem
J R
JR
Yamanaka
N
N
Rennard
S I
SI
D000199:Actins / Q000502:physiology*; D002460:Cell Line; D002633:Chemotaxis; D005333:Fetus; D005347:Fibroblasts / Q000502:physiology*; D005353:Fibronectins / Q000502:physiology*; D006801:Humans; D008168:Lung / Q000166:cytology*; D016253:Microscopy, Immunoelectron
D000199:Actins; D005353:Fibronectins