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In this study, we assessed the change in skin microbiota composition, relative abundance, and diversity with skin physiology disruption induced by SLS patch. Healthy women declaring to have a reactive skin were submitted to a 0.5% aqueous sodium lauryl sulfate solution application under occlusive patch condition for 24 h. Skin properties were characterized by tewametry, corneometry, and colorimetry and bacterial diversity was assessed by 16S rRNA sequencing. Analysis before and one day after SLS patch removal revealed an increase of skin redness and a decrease of stratum corneum hydration and skin barrier function. The relative abundance of taxa containing potential pathogens increase (Firmicutes: Staphylococcaceae; Proteobacteria: Enterobacteriaceae, Pantoea) while some of the most occurring Actinobacteria with valuable skin protection and repair capacities decreased (Micrococcus, Kocuria, and Corynebacterium). We observed an impaired skin barrier function and dehydration induced by SLS patch disturb the subtle balance of skin microbiota towards skin bacterial community dysbiosis. This study provides new insights on the skin bacterial composition and skin physiology simultaneously impaired by a SLS patch.

The revolution of ‘omics’ technologies highlighted that associated microorganisms (also called microbiota) are integrated into the metabolic functions of their hosts. Yet when performing any particular type of ‘omics’ experiment, be it metabolomics, transcriptomics, or (meta)genomics, it is extremely difficult to interpret the observed relationships between metabolites, transcripts, and microbial species. This is due to the massive amount of data generated for each ‘omics’ technology, but also the cognitive challenge of interconnecting these observations and contextualizing them in their biological (eco)system. For these reasons, there is a need for testing methods that can facilitate the translation of these ‘omics’ experimental observations into putative molecular processes or biological interactions. To accelerate the interpretation of ‘omics’ data from a description of microbial, transcript, or metabolite identities or abundances into a functional understanding of the interplay between the individual entities of the biological system, we designed a novel multi-omics strategy for the annotation and integration of metabolomics and metagenomics data. We generated metabolome and microbiome datasets by LC-MS/MS based metabolomics profiling and metagenomic sequencing, respectively. Comprehensive metabolite annotations were obtained by molecular networking and computational annotation of fragmentation spectra. Associations between microbes and GNPS molecular networks were predicted by machine learning and visualized as an extensively annotated, nested interaction network in Cytoscape. As a proof of concept, we applied this strategy to scalp swabs from a cohort of healthy volunteers with varying scalp sebum levels and were able to elucidate the antagonistic interaction between two well-characterized microbes,Staphylococcus epidermidisandCutibacterium acnes.

The majority of psoriasis patients suffer from antihistamine-resistant itch. However, therapeutic options to reduce such itch are few, and the pathogenesis of pruritus remains unclear. We previously reported that opioid systems may be involved in the pathogenesis of psoriatic itch. Here, we constructed a psoriasis-like model of scratching behavior and investigated the possible mechanism of itch in this model. Psoriasis-like lesions were induced in the skin of C57BL/6J mice by repeated topical application of imiquimod cream (IMQ) for five days (IMQmice) inducing scratching bouts. Oral administration of bepotastine besilate, a histamine H 1 receptor antagonist, did not affect the number of scratching bouts in IMQ-mice. We next examined mu-opioid receptor (MOR) and kappa-opioid receptor (KOR) protein expression in epidermis, dorsal root ganglion (DRG) and spinal cord by Western blotting. MOR was increased in the epidermis, DRG and spinal cord of IMQ-mice. In contrast, KOR was reduced in DRG and spinal cord of IMQ-mice. Based on these results, we examined the effects of topical application of naloxone (a MOR antagonist), oral administration of asimadoline hydrochloride (a peripheral KOR agonist) and ICI-199,441 (a central KOR agonist) on scratching behavior in IMQ-mice. The numbers of scratching bouts were significantly decreased in both the topical naloxone and oral ICI-199,441-treated mice without affecting locomotor activity. Meanwhile, asimadoline hydrochloride did not affect the number of scratching bouts in IMQmice. In conclusion, scratching behavior is induced in an imiquimod-induced psoriasis-like dermatitis model. In this model, histamine H 1 receptor was not involved in scratching behavior. In addition, these results suggest that peripheral MOR and central KOR may be promising as therapeutic targets for psoriatic itch.

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