Effect of Lactic Fermentation Products on Human Epidermal Cell Differentiation, Ceramide Content, and Amino Acid Production

<b><i>Introduction:</i></b> Lactic fermentation products (LFPs) are thought to affect “good” bacteria in the gut. We previously reported that oral administration of LFPs has beneficial therapeutic effects in a mouse model of atopic dermatitis. However, it is unclear how LFPs affect human epidermal cell differentiation, ceramide (Cer), and amino acid production. <b><i>Objective:</i></b> The aim of this study was to determine the effects of LFPs on epidermal cell differentiation, by assessing amino acid and Cer production. <b><i>Methods:</i></b> A 3-dimensional cultured human epidermis model and normal human epidermal keratinocytes were used. Cytotoxicity tests were performed using alamar Blue. Transepidermal water loss (TEWL) was used as an index to assess barrier function. Keratin 1 (K1), keratin 5 (K5), keratin 10 (K10), involucrin (INV), calpain 1, and transglutaminase (TGase) (markers of differentiation) and profilaggrin (proFLG) and bleomycin hydrolase (amino acid synthesis-related genes) expression levels were quantified by RT-PCR. In addition, TGase protein levels were measured by Western blotting. The intercellular lipid content of the stratum corneum was measured by high-performance thin-layer chromatography. Amino acids were quantified using an amino acid analyzer. Finally, bound water content in the stratum corneum was measured by differential scanning calorimetry. <b><i>Results:</i></b> Cell viability did not change, but TEWL was significantly decreased in the cells treated with LFPs compared with the control cells. Treatment with LFPs significantly increased expression of the late-differentiation markers INV and TGase at the RNA level. Furthermore, TGase protein expression was significantly increased by treatment with LFPs. Treating a 3-dimensional cultured epidermis model with LFPs significantly increased the intercellular lipid content of the stratum corneum and production of the amino acid arginine (Arg). The amount of bound water in the stratum corneum was increased significantly in the LFP application group. <b><i>Conclusion:</i></b> Treatment with LFPs promotes human epidermal cell differentiation and increases the intercellular content of the free fatty acid, Chol, Cer [NS], Cer [AS], and Cer [AP]. This may result in improved skin barrier function. The increased amount of Arg observed in keratinocytes may help improve water retention.

Effect of Salt Stress on Cytosine Methylation within GL2, An Arabidopsis thaliana Gene Involved in Root Epidermal Cell Differentiation. Absence of Inheritance in the Unstressed Progeny

Methylation/demethylation of cytosines is an epigenetic strategy for transcriptional regulation, allowing organisms to rapidly respond and adapt to different stimuli. In this context, and using Arabidopsis thaliana as a plant model, we explored whether an environmental stress is sufficient to trigger a change in the methylation status of Glabra-2, a master gene associated with root epidermal cell differentiation. As this gene acts mainly in the epidermis in the root, we examined the stress-driven methylation levels specifically in that tissue. We focused on the stress caused by different salt concentrations in the growth medium. When testing the effect of 20 and 75 mM NaCl, we found that there is a significant decrease in the CG methylation level of the analyzed genomic region within the epidermis. Whereas this reduction was 23% in mildly stressed plants, it turned out to be more robust (33%) in severely stressed ones. Notably, this latter epigenetic change was accompanied by an increase in the number of trichoblasts, the epidermal cell type responsible for root hair development. Analysis of an eventual inheritance of epigenetic marks showed that the non-stressed progeny (F1) of stressed plants did not inherit—in a Lamarckian fashion—the methylation changes that had been acquired by the parental individuals.

Complete Genome Sequence of Systemically Disseminated Sequence Type 8 Staphylococcal Cassette Chromosome mec Type IVl Community-Acquired Methicillin-Resistant Staphylococcus aureus

ABSTRACT Staphylococcus aureus JH4899, a community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolate collected from a patient with systematically disseminated infection, is classified as sequence type 8 and carries the staphylococcal cassette chromosome mec type IVl (SCCmecIVl). It produces TSST-1, SEC, a newly discovered enterotoxin (SE1), and epidermal cell differentiation inhibitor A (EDIN-A). Here, we present the complete genome sequence of the chromosome and a plasmid harboring the se1 and ednA genes.