Effects of season stratum corneum barrier function and skin biomarkers.

The skin on the lower legs of 25 female subjects was evaluated first in the winter, and then again in the summer of the same subjects. Barrier function was determined by measuring transepidermal water loss (TEWL), and skin hydration and dryness were evaluated by electrical measurements (Corneometer ® CM825) and visual grading. Stratum corneum (SC) was sampled using 10 sequential D-Squame sampling discs and analyzed for 2-pyrrolidone-5-carboxylic acid (PCA), keratin-1,10,11, interleukin 1α (IL-1α), interleukin 1 receptor antagonist (IL-1ra), selected ceramides, cholesterol, cholesterol sulfate, and selected free fatty acids. TEWL as well as the visual dryness grades were significantly lower in the summer while hydration was higher. PCA was significantly higher in the summer as were the keratins. The ratio IL-1ra:IL-1α, an indicator of skin inflammation, was significantly lower in the summer. The amount of protein removed by the tape strips was also significantly lower in summer indicating better SC cohesion. Among the SC lipids measured, total ceramides, individual ceramides, total fatty acids, and cholesterol were higher in summer compared to winter. Stearic acid and cholesterol sulfate were not significantly different between winter and summer.

Genus-Wide Comparative Genomics of Malassezia Delineates Its Phylogeny, Physiology, and Niche Adaptation on Human Skin.

Malassezia is a unique lipophilic genus in class Malasseziomycetes in Ustilaginomycotina, (Basidiomycota, fungi) that otherwise consists almost exclusively of plant pathogens. Malassezia are typically isolated from warm-blooded animals, are dominant members of the human skin mycobiome and are associated with common skin disorders. To characterize the genetic basis of the unique phenotypes of Malassezia spp., we sequenced the genomes of all 14 accepted species and used comparative genomics against a broad panel of fungal genomes to comprehensively identify distinct features that define the Malassezia gene repertoire: gene gain and loss; selection signatures; and lineage-specific gene family expansions. Our analysis revealed key gene gain events (64) with a single gene conserved across all Malassezia but absent in all other sequenced Basidiomycota. These likely horizontally transferred genes provide intriguing gain-of-function events and prime candidates to explain the emergence of Malassezia. A larger set of genes (741) were lost, with enrichment for glycosyl hydrolases and carbohydrate metabolism, concordant with adaptation to skin's carbohydrate-deficient environment. Gene family analysis revealed extensive turnover and underlined the importance of secretory lipases, phospholipases, aspartyl proteases, and other peptidases. Combining genomic analysis with a re-evaluation of culture characteristics, we establish the likely lipid-dependence of all Malassezia. Our phylogenetic analysis sheds new light on the relationship between Malassezia and other members of Ustilaginomycotina, as well as phylogenetic lineages within the genus. Overall, our study provides a unique genomic resource for understanding Malassezia niche-specificity and potential virulence, as well as their abundance and distribution in the environment and on human skin.

Transcriptional profiling of epidermal barrier formation in vitro.

BACKGROUND: Barrier function is integral to the health of epithelial tissues. Currently, there is a broad need to develop and improve our knowledge with regard to barrier function for reversal of mild skin irritation and dryness. However, there are few in vitro models that incorporate modulations of both lipids and epidermal differentiation programs for pre-clinical testing to aid in the understanding of barrier health. OBJECTIVE: We have generated a reconstituted epidermis on a decellularized dermis (DED) and characterized its barrier properties relative to human epidermis in order to determine its utility for modeling barrier formation and repair. METHODS: We followed the process of epidermal differentiation and barrier formation through immunocytochemistry and transcriptional profiling. We examined barrier functionality through measurements of surface pH, lipid composition, stratum corneum water content, and the ability to demonstrate topical dose-dependent exclusion of surfactant. RESULTS: Transcriptional profiling of the epidermal model during its formation reveals temporal patterns of gene expression associated with processes regulating barrier function. The profiling is supported by gradual formation and maturation of a stratum corneum and expression of appropriate markers of epidermis development. The model displays a functional barrier and a water gradient between the stratum corneum and viable layers, as determined by confocal Raman spectroscopy. The stratum corneum layer displays a normal acidic pH and an appropriate composition of barrier lipids. CONCLUSION: The epidermal model demonstrates its utility as an investigative tool for barrier health and provides a window into the transcriptional regulation of multiple aspects of barrier formation.

Modifications of the human urocortin 2 peptide that improve pharmacological properties.

Recently, we demonstrated that the corticotropin releasing factor 2 receptor agonist, urocortin 2, demonstrated anti-atrophy effects in rodent skeletal muscle atrophy models. Compared to other CRF2R agonists however, the in vivo pharmacological potency of urocortin 2 is poor when it is administered by continuous subcutaneous infusion. Therefore, we attempted to modify the structure of urocortin 2 to improve in vivo efficacy when administered by subcutaneous infusion. By substituting amino acid residues in the linker region of urocortin 2 (residues 22-32), we have demonstrated improved in vivo potency without altering selectivity, probably through reduced CRFBP binding. In addition, attempts to shorten urocortin 2 generally resulted in inactive peptides, demonstrating that the 38 amino acid urocortin 2 peptide is the minimal pharmacophore.

Distribution and accumulation of a mixture of arsenic, cadmium, chromium, nickel, and vanadium in mouse small intestine, kidneys, pancreas, and femur following oral administration in water or feed.

Manufactured gas plant (MGP) sites are contaminated with coal tar and may contain metals such as arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and vanadium (V). These metals are known to cause cancer or other adverse health conditions in humans, and the extent and cost of remediating MGP sites may be influenced by the presence of these metals. Studies assessed the distribution of these metals in female B6C3F1 mice ingesting (1) a metal mixture in water or (2) an MGP mixture in NIH-31 feed. The highest metal levels were measured in the small intestine and kidneys of mice receiving the metal mixture in water. For mice receiving the metal mixture in water, levels of As, Cd, and Cr, in the small intestine, levels of As, Cd, Cr, and V in the kidneys, levels of As and Cd in the pancreas, and levels of Cr and V in the femur were significantly greater than controls at 4, 8, 12, 16, and 24 wk. Except for Ni levels in the small intestine and femur and Cr levels in the kidneys, levels of metals were much lower in mice administered the MGP mixture in feed. The highest concentrations of metals in mice ingesting the MGP mixture in feed were found in the small intestine and kidneys, but few were significantly greater than controls. Levels of As in the small intestine at 6 and 18 wk and levels of Cr in the kidneys at 12, 18, and 24 wk were significantly greater than in controls. The data suggest that tissue burdens in small intestine, kidneys, pancreas, and femur of arsenic, cadmium, chromium, and vanadium are less when metals are present as an MGP mixture in feed than as a mixture in water. The reduced distribution and accumulation of metals in the organs of mice ingesting the MGP mixture in feed compared to the levels in organs of mice ingesting the metal mixture in water suggests that metals may be less likely to accumulate in humans ingesting MGP mixtures, thereby presenting a lower overall human health risk. The data presented indicate that the matrix in which metals are present will affect the uptake of individual metals and the organ specificity.