I. Masouye et al., ENDOTHELIAL-CELLS OF THE HUMAN MICROVASCULATURE EXPRESS EPIDERMAL FATTY-ACID-BINDING PROTEIN, Circulation research, 81(3), 1997, pp. 297-303
Epidermal fatty acid-binding protein (E-FABP), previously characterize
d in human keratinocytes, is a cytoplasmic protein of 15 kD that speci
fically binds fatty acids (FAs). Previous PAGE-immunoblotting studies
indicated that several human tissues display an immunoreactive band wi
th an electrophoretic mobility identical to that of E-FABP. The aim of
this study was to determine in which cells, other than keratinocytes,
E-FABP might be expressed. By immunohistochemistry, we show that E-FA
BP is expressed in endothelial cells of the microvasculature of the pl
acenta, heart, skeletal muscle, small intestine, lung, and renal medul
la. Interestingly, in lung, a tissue of endodermal origin, E-FABP stai
ning was also localized to secretory cells, ie, Clara cells, goblet ce
lls, and probably a subpopulation of pneumocytes. RNA isolated from cu
ltured human umbilical vein and normal human dermal microvascular endo
thelial cells was analyzed by reverse-transcriptase polymerase chain r
eaction (RT-PCR). Southern blotting and sequencing of the cloned RT-PC
R products demonstrate that endothelial E-FABP is identical to keratin
ocyte E-FABP. These data suggest that E-FABP-mediated FA transport occ
urs at the level of the microvasculature in several FA target organs.