Stratum Corneum Barrier Function: Definitions and Broad Concepts

Skin Barrier ◽  
2005 ◽  
pp. 21-24 ◽  
Keyword(s):  
Stratum Corneum ◽  
Barrier Function

scholarly journals Lipid Metabolic Events Underlying the Formation of the Corneocyte Lipid Envelope

2021 ◽  
pp. 1-13
Author(s):  
Philip W. Wertz
Keyword(s):  
Stratum Corneum ◽  
Outer Surface ◽  
Barrier Function ◽  
Skin Surface ◽  
Schiff’S Base ◽  
Cornified Envelope ◽  
Epoxy Alcohol ◽  
Viable Epidermis ◽  
Transglutaminase 1 ◽  
Base Formation

Cornified cells of the stratum corneum have a monolayer of an unusual lipid covalently attached to the outer surface. This is referred to as the corneocyte lipid envelope (CLE). It consists of a monolayer of ω-hydroxyceramides covalently attached to the outer surface of the cornified envelope. The CLE is essential for proper barrier function of the skin and is derived from linoleate-rich acylglucosylceramides synthesized in the viable epidermis. Biosynthesis of acylglucosylceramide and its conversion to the cornified envelope is complex. Acylglucosylceramide in the bounding membrane of the lamellar granule is the precursor of the CLE. The acylglucosylceramide in the limiting membrane of the lamellar granule may be oriented with the glucosyl moiety on the inside. Conversion of the acylglucosylceramide to the CLE requires removal of the glucose by action of a glucocerebrosidase. The ester-linked fatty acid may be removed by an as yet unidentified esterase, and the resulting ω-hydroxyceramide may become ester linked to the outer surface of the cornified envelope through action of transglutaminase 1. Prior to removal of ester-linked fatty acids, linoleate is oxidized to an epoxy alcohol through action of 2 lipoxygenases. This can be further oxidized to an epoxy-enone, which can spontaneously attach to the cornified envelope through Schiff’s base formation. Mutations of genes coding for enzymes involved in biosynthesis of the CLE result in ichthyosis, often accompanied by neurologic dysfunction. The CLE is recognized as essential for barrier function of skin, but many questions about details of this essentiality remain. What are the relative roles of the 2 mechanisms of lipid attachment? What is the orientation of acylglucosylceramide in the bounding membrane of lamellar granules? Some evidence supports a role for CLE as a scaffold upon which intercellular lamellae unfold, but other evidence does not support this role. There is also controversial evidence for a role in stratum corneum cohesion. Evidence is presented to suggest that covalently bound ω-hydroxyceramides serve as a reservoir for free sphingosine that can serve in communicating with the viable epidermis and act as a potent broad-acting antimicrobial at the skin surface. Many questions remain.

Tight junction dysfunction in the stratum granulosum leads to aberrant stratum corneum barrier function in claudin-1-deficient mice

2013 ◽  
Vol 70 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Tomoko Sugawara ◽  
Noriko Iwamoto ◽  
Masaya Akashi ◽  
Taro Kojima ◽  
Junzo Hisatsune ◽  
...  
Keyword(s):  
Tight Junction ◽  
Stratum Corneum ◽  
Barrier Function ◽  
Stratum Granulosum ◽  
Deficient Mice

Effects of calcipotriol on stratum corneum barrier function, hydration and cell renewal in humans

1996 ◽  
Vol 135 (4) ◽  
pp. 545-549 ◽  
Author(s):  
I. EFFENDY ◽  
C. KWANGSUKSTITH ◽  
M. CHIAPPE ◽  
H.I. MAIBACH
Keyword(s):  
Stratum Corneum ◽  
Barrier Function ◽  
Cell Renewal

Effect of lactic acid isomers on keratinocyte ceramide synthesis, stratum corneum lipid levels and stratum corneum barrier function

1996 ◽  
Vol 288 (7) ◽  
pp. 383-390 ◽  
Author(s):  
A. V. Rawlings ◽  
A. Davies ◽  
M. Carlomusto ◽  
S. Pillai ◽  
K. Zhang ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Stratum Corneum ◽  
Barrier Function ◽  
Lipid Levels ◽  
Stratum Corneum Lipid ◽  
Ceramide Synthesis
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