Moisturizers change the mRNA expression of enzymes synthesizing skin barrier lipids

Abstract

In a previous study, 7-week treatment of normal human skin with two test moisturizers, Complex cream and Hydrocarbon cream, was shown to affect mRNA expression of certain genes involved in keratinocyte differentiation. Moreover, the treatment altered transepidermal water loss (TEWL) in opposite directions. In the present study, the mRNA expression of genes important for formation of barrier lipids, i.e., cholesterol, free fatty acids and ceramides, was examined. Treatment with Hydrocarbon cream, which increased TEWL, also elevated the gene expression of GBA, SPTLC2, SMPD1, ALOX12B, ALOXE3, and HMGCS1. In addition, the expression of PPARG was decreased. On the other hand, Complex cream, which decreased TEWL, induced only the expression of PPARG, although not confirmed at the protein level. Furthermore, in the untreated skin, a correlation between the mRNA expression of PPARG and ACACB, and TEWL was found, suggesting that these genes are important for the skin barrier homeostasis. The observed changes further demonstrate that long-term treatment with certain moisturizers may induce dysfunctional skin barrier, and as a consequence several signaling pathways are altered.

Skin Barrier Responses to Moisturizers: Functional and Biochemical Changes

“…At the same time, the moisturizers had no effect on protein expression of three analyzed proteins: involucrin, transglutaminase 1, and fi laggrin. Stratum corneum thickness, epidermal thickness, the size of corneocytes, and nonpolar lipid staining were also unaffected by the treatments [ 28,29 ] .…”

“…In the present investigation, after long-term treatment, moisturizers were examined for their effect on the skin barrier with regard to such factors as pH, lipid type, the presence of a humectant, as well as complexity of the product [27][28][29]50 ] . Moisturizers are able to modify the skin barrier function, detected as changes in TEWL, skin capacitance, and susceptibility to an irritant, and also to change the mRNA expression of certain genes involved in the assembly, differentiation, and desquamation of the stratum corneum, as well as lipid metabolism.…”

“…Biopsies were used for investigating the biochemical changes in the skin: the shave biopsies were used for gene expression analysis using quantitative real-time polymerase chain reaction (QRT-PCR) and the punch biopsies for histological and other molecular evaluations. Moreover, the skin of the forearms was investigated for functional changes, in a way similar to the fi rst study, using noninvasive methods [ 28,29 ] .…”

“…Due to such choice of ingredients, the following factors were examined: (1) the impact of a humectant (urea); (2) difference between creams of minimum complexity (Hydrocarbon, Canola and Canola/urea creams) and a cream containing more ingredients (Complex cream); and (3) different types of lipids (hydrocarbons or vegetable oil). All test preparations had their pH adjusted to about 5 [27][28][29] . Table 37.1 presents detailed compositions along with the number of volunteers testing each preparation.…”

The effect of two endogenous retinoids on the mRNA expression profile in human primary keratinocytes, focusing on genes causing autosomal recessive congenital ichthyosis

“…Analysis was performed using an ABI PRISM 7500Fast sequence detection system (Applied Biosystems) as described elsewhere [8, 9]. The relative mRNA expression was determined by the 2 (−ΔΔCt) method and analyzed by one-way ANOVA followed by Tukey’s multiple comparison test (Prism 5.04 software, GraphPad Software Inc., La Jolla, CA).…”