Sphingolipids of the Stratum Corneum and Lamellar Granules of Fetal Rat Epidemis

Abstract

Sphingolipid profiles have been determined for whole epidermis, a subcellular fraction enriched in lamellar granules, and a fraction enriched with stratum corneum derived from fetal rat skin. In each case, 4 groups of glucosylceramides and 6 groups of ceramides have been identified by thin-layer chromatographic comparison with structurally defined sphingolipids from pig epidermis. The relative amounts of the sphingolipids in each preparation have been quantified by photodensitometry of the charred chromatograms. Lamellar granule sphingolipids had elevated proportions, relative to whole epidermis, of acylceramides, acylglucosylceramides, and a glucosylceramide fraction which may be produced by O-deacylation of the acylglucosylceramides. The fetal stratum corneum-enriched samples contain reduced proportions of all glucosylceramides and acylceramides as compared to lamellar granule lipids. The possible functions of these sphingolipids in the assembly and structure of lamellar granules are discussed.

Thematic review series: Skin Lipids. The role of epidermal lipids in cutaneous permeability barrier homeostasis

“…The lipids in the lamellar bodies are precursors of the stratum corneum extracellular lipids. After secretion, these lamellar body-derived lipids are further metabolized in the stratum corneum extracellular spaces by enzymes that are cosecreted in lamellar bodies (18)(19)(20)(21)(22). Specifically, b-glucocerebrosidase converts glucosylceramides into ceramides (23,24), acidic sphingomyelinase converts sphingomyelin into ceramides (25,26), and phospholipases convert phospholipids into free fatty acids and glycerol (27,28).…”

Thematic Review Series: Skin Lipids. Antimicrobial lipids at the skin surface

“…Much of the accumulating lipid is packaged in the form of small membranous organelles known as lamellar granules (42)(43)(44)(45)(46). The lamellar granules are round to ovoid in shape and consist of a unitbounding membrane surrounding one or several stacks of lamellar disks.…”

“…The lamellar granules are round to ovoid in shape and consist of a unitbounding membrane surrounding one or several stacks of lamellar disks. Isolated lamellar granules contain abundant phospholipids, cholesterol, and glycolipids (43)(44)(45)(46). A number of hydrolytic enzymes are also associated with the granules (44,45).…”

Sphingolipid transport in eukaryotic cells

“…It is known that intracellular pools of glycosphingolipids exist in glycosphingolipid storage diseases (see [75]), and that glucosylceramide (GlcCer) is stored in lamellar bodies in keratinocytes as a precursor for extracellular skin Cers [97,98], but it has become clear that intracellular pools of sphingolipids are a more general phenomenon [99^102]. Sphingolipids have been colocalized with cytoskeletal elements using £uorescence microscopy, but the necessity of using detergent has complicated the interpretations [103^106].…”