ABSTRACT
Netherton syndrome is a monogenic autosomal recessive disorder primarily characterized by the detachment of the uppermost layer of the epidermis, the stratum corneum It results from mutations in the SPINK5 gene, which codes for a kallikrein inhibitor. Uncontrolled kallikrein activity leads to premature desquamation, resulting in a severe epidermal barrier defect and subsequent life-threatening systemic infections and chronic cutaneous inflammation. Here, we show that genetic activation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nfe2l2/Nrf2) in keratinocytes of Spink5 knockout mice, a model for Netherton syndrome, significantly alleviates their cutaneous phenotype. Nrf2 activation promoted attachment of the stratum corneum and concomitant epidermal barrier function, and reduced the expression of pro-inflammatory cytokines such as tumor necrosis factor α and thymic stromal lymphopoietin. Mechanistically, we show that Nrf2 activation induces overexpression of secretory leukocyte protease inhibitor (Slpi), a known inhibitor of kallikrein 7 and elastase 2, in mouse and human keratinocytes in vivo and in vitro, respectively. In the Spink5-deficient epidermis, the upregulation of Slpi is likely to promote stabilization of corneodesmosomes, thereby preventing premature desquamation. Our results suggest pharmacological NRF2 activation as a promising treatment modality for Netherton syndrome patients.This article has an associated First Person interview with the first author of the paper.
Subject(s)
NF-E2-Related Factor 2/genetics , Netherton Syndrome/genetics , Netherton Syndrome/pathology , Skin/pathology , Animals , Cell Adhesion , Cell Differentiation , Chemokines/metabolism , Disease Models, Animal , Epidermis/pathology , Humans , Inflammation/pathology , Inflammation Mediators/metabolism , Integrases/metabolism , Keratinocytes/pathology , Mice, Inbred C57BL , Mice, Knockout , NAD(P)H Dehydrogenase (Quinone)/metabolism , NF-E2-Related Factor 2/metabolism , Secretory Leukocyte Peptidase Inhibitor/metabolism , Serine Peptidase Inhibitor Kazal-Type 5/deficiency , Serine Peptidase Inhibitor Kazal-Type 5/geneticsABSTRACT
We developed activography to map enzymatic activities on tissue sections using activity-based probes. The assay was validated using a new protease-activity probe on skin biopsies to provide proof-of-concept. Activography is more selective and technically easier than the established in situ zymography, thus, adaptable in routine running clinico-chemical laboratories.
