ANALYSIS OF HETEROGENEITY OF HUMAN KERATINOCYTE POPULATIONS BY THEIR ADHESION TO SUBSTRATE AND THE KERATIN 19 TO
ACTIN RATIO
O. G. Spichkina,1 G. P. Pinaev, Yu. P. Petrov
Institute Cytology RAS, St. Petersburg;
1 e-mail: olga_spichkina@mail.ru
Keratin 19 is reported to be a marker for skin stem cells and that assumes an independent subpopulation of these cells in keratinocyte population.
In addition, keratinocytes have natural affinity to extracellular matrix proteins. The aim of this work was to reveal subpopulations of keratinocytes cultivated
on the substrates of collagen I type, laminin-2/4 and fibronectin, and distinguished by keratin 19/actin ratio (G/R). The area of cell projection on a substrate,
perimeter, the spreading coefficient and G/R were measured. Both on fibronectin and laminin-2/4, keratinocyte populations were morphologically homogeneous
with large cells comprising 12 and 20 percents of the population, respectively. On fibronectin, correlation between morphological parameters of the cells and the
keratin 19/actin ratio was not found. The cells growth on collagen behaved as a heterogeneous population, with the large cells compressing more than 50 percents
of the population. An average, the size of the cells growing on collagen was twice as large as than of the cells cultivated on fibronectin. On the other hand,
correlation between the cell size and G/R was revealed in the cells growth both on collagen and laminin-2/4. The cells with lower G/R value display a larger size
and extent of spreading. We assume that this correlation may be determined by α1 and α2, integrins characteristic of these cells. Our results cast
doubts on whether stem cells are present in the culture of human skin keratinocytes.
Key words: actin, adhesion, collagen I type, fibronectin, heterogeneity of cell population, human keratinocytes, keratin 19, laminin-2/4
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