The present invention relates to the use, in cosmetics and in therapeutics, of at least one antimicrobial protein belonging to the ribonuclease family, ribonuclease 7, or of polypeptides derived from said protein, notably as a marker for evaluating the condition of the epidermis. It further relates to the use of at least one polypeptide according to the invention, of at least one nucleic acid sequence coding for a polypeptide according to the invention, or of at least one agent that modulates the expression or the activity, notably biological, of said polypeptide or of its interaction with an element of the extracellular matrix, for the preparation of compositions intended for the prevention and/or treatment of skin disorders.