The present invention relates to methods of preventing or decreasing the severity of scarring in a subject comprising: obtaining a pharmaceutical composition comprising a single chain urokinase plasminogen activator molecule (scuPA) or a scuPA mimetic; and administering the pharmaceutical composition to a subject; wherein scarring in the subject is either prevented or decreased relative to an amount of scarring that would be expected if the pharmaceutical composition were not administered to the subject. The invention also relates to methods of screening for compounds that prevent or decrease the severity of scarring in a subject.