title: Selective Substrates and Inhibitors for Kallikrein-Related Peptidase 7 (KLK7) Shed Light on KLK Proteolytic Activity in the Stratum Corneum.
abstract: Proteases have pivotal roles in the skin's outermost layer, the epidermis. In the stratum corneum, serine proteases from the kallikrein-related peptidase (KLK) family have been implicated in several key homeostatic processes, including desquamation. However, the precise contribution of specific KLKs to each process remains unclear. To address this, we used a chemical biology approach and designed selective substrates and inhibitors for KLK7, the most abundant KLK protease in the stratum corneum. The resulting KLK7 inhibitor is the most potent inhibitor of this protease reported to date (Ki= 140 pM), and displays at least 1,000-fold selectivity over several proteases that are related by function (KLK5 and KLK14) or specificity (chymotrypsin). We then used substrates and inhibitors for KLK5, KLK7, and KLK14 to explore the activity of each protease in the stratum corneum using casein zymography and an ex vivo desquamation assay. These experiments provide the most detailed assessment of each KLK's contribution to corneocyte shedding in the plantar stratum corneum, revealing that inhibition of KLK7 alone is sufficient to block shedding, whereas KLK5 is also a major contributor. Collectively, these findings unveil chemical tools for studying KLK activity and demonstrate their potential for characterizing KLK biological functions in epidermal homeostasis.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia; Laboratory of Genetic Skin Diseases, INSERM UMR 1163 and Imagine Institute of Genetic Diseases, Paris, France; Université Paris V Descartes-Sorbonne Paris Cité, Paris, France.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: de Veer
authors.affiliation: Laboratory of Genetic Skin Diseases, INSERM UMR 1163 and Imagine Institute of Genetic Diseases, Paris, France; Université Paris V Descartes-Sorbonne Paris Cité, Paris, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Furio
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Joakim E
authors.initials: JE
authors.lastname: Swedberg
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Munro
authors.affiliation: Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Brattsand
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia; Australian Prostate Cancer Research Centre, Translational Research Institute, Brisbane, Queensland, Australia.
authors.forename: Judith A
authors.initials: JA
authors.lastname: Clements
authors.affiliation: Laboratory of Genetic Skin Diseases, INSERM UMR 1163 and Imagine Institute of Genetic Diseases, Paris, France; Université Paris V Descartes-Sorbonne Paris Cité, Paris, France; Department of Genetics, Necker Hospital for Sick Children, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Hovnanian
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia. Electronic address: j2.harris@qut.edu.au.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Harris
mesh_terms: D004817:Epidermis / Q000378:metabolism*; D006801:Humans; D007610:Kallikreins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D019151:Peptide Library
chemical_list: D019151:Peptide Library; C425336:KLK14 protein, human; C400147:KLK5 protein, human; C082472:KLK7 protein, human; D007610:Kallikreins