Endogenous β-glucocerebrosidase activity in Abca12⁻/⁻epidermis elevates ceramide levels after topical lipid application but does not restore barrier function
| Autor: | Nicholas J. Hernandez, Michael L. Fitzgerald, Lee Dolat, Ruth Welti, Paul M Cavallaro, Gregory A. Grabowski, Mason W. Freeman, Jorge F. Haller, Stephanie J. Soscia |
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| Rok vydání: | 2013 |
| Předmět: |
Ceramide
Immunoblotting QD415-436 Lamellar granule Ceramides Glucosylceramides Biochemistry skin permeability barrier Serine chemistry.chemical_compound Mice Endocrinology Organ Culture Techniques glucosylceramide ABCA12 antibody Stratum corneum medicine Animals Humans ABCA12 harlequin ichthyosis Barrier function Research Articles Skin Mice Knockout biology Epidermis (botany) integumentary system Reverse Transcriptase Polymerase Chain Reaction Cell Biology Immunohistochemistry Lipids Cell biology medicine.anatomical_structure HEK293 Cells chemistry biology.protein Glucosylceramidase ATP-Binding Cassette Transporters Chromatography Thin Layer Epidermis Ex vivo |
| Zdroj: | Journal of Lipid Research, Vol 55, Iss 3, Pp 493-503 (2014) |
| ISSN: | 1539-7262 |
| Popis: | ABCA12 mutations disrupt the skin barrier and cause harlequin ichthyosis. We previously showed Abca12(-/-) skin has increased glucosylceramide (GlcCer) and correspondingly lower amounts of ceramide (Cer). To examine why loss of ABCA12 leads to accumulation of GlcCer, de novo sphingolipid synthesis was assayed using [(14)C]serine labeling in ex vivo skin cultures. A defect was found in β-glucocerebrosidase (GCase) processing of newly synthesized GlcCer species. This was not due to a decline in GCase function. Abca12(-/-) epidermis had 5-fold more GCase protein (n = 4, P < 0.01), and a 5-fold increase in GCase activity (n = 3, P < 0.05). As with Abca12(+/+) epidermis, immunostaining in null skin showed a typical interstitial distribution of the GCase protein in the Abca12(-/-) stratum corneum. Hence, we tested whether the block in GlcCer conversion could be circumvented by topically providing GlcCer. This approach restored up to 15% of the lost Cer products of GCase activity in the Abca12(-/-) epidermis. However, this level of barrier ceramide replacement did not significantly reduce trans-epidermal water loss function. Our results indicate loss of ABCA12 function results in a failure of precursor GlcCer substrate to productively interact with an intact GCase enzyme, and they support a model of ABCA12 function that is critical for transporting GlcCer into lamellar bodies. |
| Databáze: | OpenAIRE |
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