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Betaine derivatives are considered major ingredients of shampoos and are commonly used as antistatic and viscosity-increasing agents. Several studies have also suggested that betaine derivatives can be used as antimicrobial agents. However, the antifungal activity and mechanism of action of betaine derivatives have not yet been fully understood. In this study, we investigated the antifungal activity of six betaine derivatives against Malassezia restricta, which is the most frequently isolated fungus from the human skin and is implicated in the development of dandruff. We found that, among the six betaine derivatives, lauryl betaine showed the most potent antifungal activity. The mechanism of action of lauryl betaine was studied mainly using another phylogenetically close model fungal organism, Cryptococcus neoformans, because of a lack of available genetic manipulation and functional genomics tools for M. restricta. Our genome-wide reverse genetic screening method using the C. neoformans gene deletion mutant library showed that the mutants with mutations in genes for cell membrane synthesis and integrity, particularly ergosterol synthesis, are highly sensitive to lauryl betaine. Furthermore, transcriptome changes in both C. neoformans and M. restricta cells grown in the presence of lauryl betaine were analyzed and the results indicated that the compound mainly affected cell membrane synthesis, particularly ergosterol synthesis. Overall, our data demonstrated that lauryl betaine influences ergosterol synthesis in C. neoformans and that the compound exerts a similar mechanism of action on M. restricta.

(1) Background: Dental calculus works as a niche wherein pathogenic bacteria proliferate in the oral cavity. Previous studies revealed the anticalculus activity of pyrophosphates, however there was no clinical study that evaluated microbiome changes associated with calculus inhibition. Therefore, the aim of this randomized clinical trial was to evaluate the calculus inhibition of pyrophosphate-containing toothpaste and its effect on oral microbiome changes. (2) Methods: Eighty subjects with a calculus index &ge, 2 on the lingual of the mandibular anterior tooth were randomly allocated to the test group that pyrophosphate-containing toothpaste was given to or the placebo control group. Full mouth debridement and standardized tooth brushing instruction were given before the allocation. Plaque index, gingival index, calculus index, probing depth, and bleeding on probing were measured at the baseline, and at 4, 8 and 12 weeks. Genomic DNA was extracted from the plaque samples collected at the baseline and at 12 weeks, and 16S ribosomal RNA gene amplicon sequencing was applied for microbiome analysis. (3) Results: None of the clinical parameters showed significant differences by visits or groups, except the plaque index of the test group, which reduced significantly between 4 and 12 weeks. A significant difference of microbiome between the baseline and 12 weeks was observed in the test group. Between baseline and 12 weeks, the proportion of Spirochetes decreased in the control group, and the proportions of Proteobacteria, Fusobacteria and Spirochetes in the phylum level and the proportions of Haemophilus, Fusobacterium and Capnocytophaga in the genus level decreased in the test group. In the test group, as plaque index decreased, Streptococcus increased, and Fusobacterium and Haemophilus parainfluenza decreased. (4) Conclusion: The use of pyrophosphate-containing toothpaste effectively inhibited the dysbiosis of the oral microbiome and the proliferation of pathogenic species in periodontal disease. Clinically, plaque formation in the pyrophosphate-containing toothpaste group was effectively decreased, however there was no significant change in calculus deposition.

Background Atopic dermatitis (AD) represents the most common inflammatory skin disorder in children showing massive infiltration of immune cells. The colonization of AD-afflicted skin by Staphylococcus aureus and S. aureus-derived extracellular vesicles (SEVs) has been associated with AD pathogenesis; however, the molecular mechanism underlying SEV-mediated inflammatory responses remains unclear. Objective We investigated how SEVs can mediate inflammatory responses in AD pathogenesis by examining the effect of SEVs on human dermal microvascular endothelia cells (HDMECs). Methods HDMECs were treated with SEVs, and the expression of cell adhesion molecules or cytokines was assessed using RT-qPCR, Western blot or cytokine array analyses. The receptor for SEVs and related signalling molecules in HDMECs were addressed and verified via gene knockdown or inhibitor experiments. The recruitment assay of human THP-1 monocytic cells on HDMECs was performed after SEV treatment in the presence or absence of the verified receptor or signalling molecule. Results SEVs, but not other gram-positive bacteria-derived extracellular vesicles, directly activated HDMECs by increasing the expression of cell adhesion molecules (E-selectin, VCAM1 and ICAM1) and that of IL-6, the inflammatory cytokine; consequently, they enhanced the recruitment of THP-1 monocytic cells to HDMECs. The SEV-induced HDMEC activation was dependent on Toll-like receptor 4 and the NF-κB signalling pathway, which was rapidly activated within 1 hour post-treatment and followed by an upregulation of cell adhesion molecules and IL-6 at later time-points. Moreover, SEV-mediated HDMEC responses were more rapid and intense than those induced by the same protein concentrations of S. aureus extracts. Conclusions & clinical relevance SEVs as proinflammatory factors could mediate immune cell infiltration in AD by efficiently inducing endothelial cell activation and monocyte recruitment, which may provide insights into alleviating the S. aureus-mediated onset or progression of AD and its phenotypes.

Acne vulgaris is an inflammatory disease occurring in the pilosebaceous unit and is the most common skin condition in young people. A gram-positive bacterium, Propionibacterium acnes, has been suspected to contribute to the development of acne. Here, we report that P. acnes constitutively releases extracellular vesicles (EVs) exhibiting typical EV morphology and size. Moreover, the P. acnes-derived EVs (PEVs) can induce acne-like phenotypes in human epidermal keratinocytes and a reconstituted human skin model. PEVs significantly induced inflammatory cytokines IL-8 and GM-CSF and dysregulated epidermal differentiation by increasing proliferating keratinocytes and decreasing epidermal keratin 10 and desmocollin 1 levels. PEVs showed strong effects, evoking these responses at earlier time points compared with P. acnes extract at the same protein concentration. We verified that PEVs were internalized via clathrin-dependent endocytosis into keratinocytes and that PEV-induced cellular responses occurred via Toll-like receptor 2-dependent signal cascades. Furthermore, PEVs showed a stronger effect than keratinocytes in inducing inflammatory cytokines in myeloid cells. Collectively, our study suggests that PEVs induce acne-like phenotypes in a unique way; therefore, inhibiting the release of EVs from P. acnes or targeting PEV-mediated signaling pathways could represent an alternative method for alleviating acne occurrence and phenotypes.

We investigate the relationship between scalp microbiota and dandruff/seborrhoeic dermatitis (D/SD), an unpleasant scalp disorder common in human populations. Bacterial and fungal community analyses on scalp of 102 Korean were performed by next-generation sequencing. Overall scalp microbiome composition significantly differed between normal and disease groups, and especially co-occurrence network of dominant members was breakdown in disease groups. These findings will provide novel insights into shifts of microbial community relevant to D/SD.

A B S T R A C T Background: Staphylococcus aureus produces various toxins and enzymes, and its presence can exacerbate skin conditions. Previous studies have shown that S. aureus is involved in skin deterioration, even in normal tissue. Biofilm strains show much greater resistance to antimicrobial agents and therefore require a much higher concentration of biocide than planktonic counterparts. Objective: As such, alternative strategies and more effective therapeutic agents against biofilmproducing S. aureus in skin are of great interest. Therefore, we turned our attention to differences in 50 clinical biofilm strains isolated from human facial skin. Methods: Based on S. aureus density on facial skin, we divided donors into two groups: relatively low density (LSG) and high density (HSG). In general, strong biofilm-forming strains were detected in the HSG donors. Two strains from each of the groups were submitted to gene microarray analysis to investigate expression differences and confirmed by RT-PCR. Results: In total, 111 of 7775 genes were differentially expressed between low (SA2 and SA7) vs. high (SA10 and SA33) biofilm-forming clinical strains. These genes include already well-known as biofilm formation related genes like icaABCD and lrgAB, and newly identified genes (sdrC, sspBCP) by RT-PCR. Comparison of gene expression differences between the two groups available at NCBI Gene Expression Omnibus accession number GSE44268. Conclusion: Our results suggest that S. aureus density in the skin is closely related to biofilm-forming ability, and we have identified several potential target genes that may be involved in regulating biofilm