The expression pattern of galectins during human epidermal morphogenesis.

Galectins constitute a phylogenetically conserved family of proteins with high binding affinity for glycoconjugates bearing β-galactoside residues. Surprisingly, knowledge of the expression pattern of galectins during human epidermal morphogenesis is very limited. Fifty-eight biopsy skin specimens obtained from human embryos and 10 biopsy specimens obtained from healthy adult volunteers were processed for immunohistochemistry using a panel of antibodies against galectins 1, 3, 7, and 9. Fetal human epidermis was devoid of any galectin 1 immunoreactivity, whereas clear-cut changes were found in the galectin 3 immunoreactivity of fetal epidermis with advancing gestational age. The expression pattern of galectins 7 and 9 remained constant at all stages of gestation. The changes in galectin 3 immunoreactivity of human fetal epidermis with advancing gestational age, which are reported here for the first time, suggest that this galectin and its ligands may be implicated in the molecular events underlying human epidermal morphogenesis. It remains to be elucidated in future investigations whether the expression pattern of galectins, particularly that of galectin 3, in the developing human epidermis reveals alterations in fetuses with inherited cutaneous disorders that may be important for prenatal diagnosis of these disorders.