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Biochim Biophys Acta. 2014 Mar;1841(3):280-94. doi: 10.1016/j.bbalip.2013.11.007. Epub 2013 Nov 18.

Role of lipids in the formation and maintenance of the cutaneous permeability barrier.

Author information

1
Metabolism Section, Medicine Service and Dermatology Service, Department of Veterans Affairs Medical Center, University of California San Francisco, San Francisco, CA 94121, USA. Electronic address: kenneth.feingold@ucsf.edu.
2
Metabolism Section, Medicine Service and Dermatology Service, Department of Veterans Affairs Medical Center, University of California San Francisco, San Francisco, CA 94121, USA.

Abstract

The major function of the skin is to form a barrier between the internal milieu and the hostile external environment. A permeability barrier that prevents the loss of water and electrolytes is essential for life on land. The permeability barrier is mediated primarily by lipid enriched lamellar membranes that are localized to the extracellular spaces of the stratum corneum. These lipid enriched membranes have a unique structure and contain approximately 50% ceramides, 25% cholesterol, and 15% free fatty acids with very little phospholipid. Lamellar bodies, which are formed during the differentiation of keratinocytes, play a key role in delivering the lipids from the stratum granulosum cells into the extracellular spaces of the stratum corneum. Lamellar bodies contain predominantly glucosylceramides, phospholipids, and cholesterol and following the exocytosis of lamellar lipids into the extracellular space of the stratum corneum these precursor lipids are converted by beta glucocerebrosidase and phospholipases into the ceramides and fatty acids, which comprise the lamellar membranes. The lipids required for lamellar body formation are derived from de novo synthesis by keratinocytes and from extra-cutaneous sources. The lipid synthetic pathways and the regulation of these pathways are described in this review. In addition, the pathways for the uptake of extra-cutaneous lipids into keratinocytes are discussed. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.

KEYWORDS:

Ceramide synthesis; Cholesterol synthesis; Fatty acid synthesis; Glucosylceramide; Lamellar body; Stratum corneum

PMID:
24262790
DOI:
10.1016/j.bbalip.2013.11.007
[Indexed for MEDLINE]

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