BACKGROUND: Recent advances in sequencing technologies have enabled metagenomic analyses of many human body sites. Several studies have catalogued the composition of bacterial communities of the ...surface of human skin, mostly under static conditions in healthy volunteers. Skin injury will disturb the cutaneous homeostasis of the host tissue and its commensal microbiota, but the dynamics of this process have not been studied before. Here we analyzed the microbiota of the surface layer and the deeper layers of the stratum corneum of normal skin, and we investigated the dynamics of recolonization of skin microbiota following skin barrier disruption by tape stripping as a model of superficial injury. RESULTS: We observed gender differences in microbiota composition and showed that bacteria are not uniformly distributed in the stratum corneum. Phylogenetic distance analysis was employed to follow microbiota development during recolonization of injured skin. Surprisingly, the developing neo-microbiome at day 14 was more similar to that of the deeper stratum corneum layers than to the initial surface microbiome. In addition, we also observed variation in the host response towards superficial injury as assessed by the induction of antimicrobial protein expression in epidermal keratinocytes. CONCLUSIONS: We suggest that the microbiome of the deeper layers, rather than that of the superficial skin layer, may be regarded as the host indigenous microbiome. Characterization of the skin microbiome under dynamic conditions, and the ensuing response of the microbial community and host tissue, will shed further light on the complex interaction between resident bacteria and epidermis.
Microbiome and skin diseases Zeeuwen, Patrick L J M; Kleerebezem, Michiel; Timmerman, Harro M ...
Current opinion in allergy and clinical immunology,
2013-October, Letnik:
13, Številka:
5
Journal Article
This article reviews recent findings on the skin microbiome. It provides an update on the current understanding of the role of microbiota in healthy skin and in inflammatory and allergic skin ...diseases.
Advances in computing and high-throughput sequencing technology have enabled in-depth analysis of microbiota composition and functionality of human skin. Most data generated to date are related to the skin microbiome of healthy volunteers, but recent studies have also addressed the dynamics of the microbiome in diseased and injured skin. Currently, reports are emerging that evaluate the strategies to manipulate the skin microbiome, intending to modulate diseases and/or their symptoms.
The microbiome of normal human skin was found to have a high diversity and high interpersonal variation. Microbiota compositions of diseased lesional skin (in atopic dermatitis and psoriasis) showed distinct differences compared with healthy skin. The function of microbial colonization in establishing immune system homeostasis has been reported, whereas host-microbe interactions and genetically determined variation of stratum corneum properties might be linked to skin dysbiosis. Both are relevant for cutaneous disorders with aberrant immune responses and/or disturbed skin barrier function. Modulation of skin microbiota composition to restore host-microbiota homeostasis could be future strategies to treat or prevent disease.
No NLRP3 genetic variants were found in any of the analyzed cell types derived from 2 patients with Schnitzler syndrome without NLRP3 variants in whole blood (Table I). Because we have previously ...demonstrated that IL-1β is a pivotal mediator of the clinical signs of Schnitzler syndrome,2,5 we proceeded to investigate the functional consequences of the NLRP3 mosaic mutations on IL-1β and IL-6 production in PBMCs (see the Methods section in this article's Online Repository at www.jacionline.org). The identified variant is considered a benign polymorphism.E5 In patient 7 we detected a known missense mutation in the NACHT domain of the NLRP3 gene (c.1569C>G; p.F523L), which was previously reported as disease causing in 2 infants with NOMID/CINCA, a severe early-onset form of CAPS.E6Canonical SS, Variants located in a canonical splice site; Coding+SS, all variants located either in exonic regions or canonical splice sites; Indels, Insertions or deletions; Known variant (HGMD), variants described as pathogenic in the Human Gene Mutation Database (www.hgmd.org); Missense (phyloP >2.5),E4 highly conserved missense variants with a phyloP >2.5; Nonsense, nonsense variants; Nonsynonymous, variants leading to an amino acid change; Not seen before (in house), variants that have not been detected in 672 in-house sequenced whole exomes; Patient, patient who has undergone whole-exome sequencing; Total no. of variants, all variants detected by using whole-exome sequencing.
Recent work has demonstrated an unexpected prevalence of copy number variation in the human genome, and has highlighted the part this variation may play in predisposition to common phenotypes. Some ...important genes vary in number over a high range (e.g. DEFB4, which commonly varies between two and seven copies), and have posed formidable technical challenges for accurate copy number typing, so that there are no simple, cheap, high-throughput approaches suitable for large-scale screening. We have developed a simple comparative PCR method based on dispersed repeat sequences, using a single pair of precisely designed primers to amplify products simultaneously from both test and reference loci, which are subsequently distinguished and quantified via internal sequence differences. We have validated the method for the measurement of copy number at DEFB4 by comparison of results from >800 DNA samples with copy number measurements by MAPH/REDVR, MLPA and array-CGH. The new Paralogue Ratio Test (PRT) method can require as little as 10 ng genomic DNA, appears to be comparable in accuracy to the other methods, and for the first time provides a rapid, simple and inexpensive method for copy number analysis, suitable for application to typing thousands of samples in large case-control association studies.
We investigated differentiation and barrier properties of epidermal equivalents derived from ichthyosis vulgaris keratinocytes that were homozygous for FLG null mutations. We found no effect on ...penetration of tracer molecules, compared with filaggrin proficient keratinocytes.
Recently, it was shown that lesional skin of atopic dermatitis patients expresses low levels of some antimicrobial peptides, compared with psoriasis patients. Here we performed microarray analysis on ...mRNA from purified lesional epidermal cells of patients with chronic plaque psoriasis and chronic atopic dermatitis, to investigate whether this is a general phenomenon for host defense proteins, and how specific it is for this class of molecules. Microarray data were confirmed on a selected set of genes by quantitative PCR and at the protein level by immunohistochemistry. We found overexpression of many antimicrobial proteins in keratinocytes from psoriatic skin compared with atopic dermatitis skin. Interestingly, we observed that markers of normal differentiation and the activated/hyperproliferative epidermal phenotype were expressed at equal levels. Chronic lesions of psoriasis and atopic dermatitis patients are remarkably similar with respect to cellular proliferation. We conclude that psoriatic epidermis expresses high levels of host defense proteins compared with atopic dermatitis epidermis, and this phenomenon appears to be specific for these proteins. It remains to be investigated whether this is caused by genetic polymorphisms in pathways leading to an epidermal antimicrobial response, or by differences in the cellular infiltrate in psoriasis compared with atopic dermatitis.
Mutations in the filaggrin gene, which cause the skin disease ichthyosis vulgaris and are a genetic risk factor for atopic dermatitis, alter the cutaneous microbiome thereby affecting keratinocyte ...host defense responses following skin barrier disruption.
Background: Chronic mucocutaneous candidiasis (CMC) and hyper-IgE syndrome (HIES) are primary immunodeficiencies mainly caused by mutations in STAT1 and STAT3, respectively. CMC and HIES patients ...have an increased risk for skin and mucosal infections with fungal pathogens and Staphylococcus aureus. However, it is unknown whether the genetic defects in these patients also affect the skin and mucosal microbiome, which in turn may influence host defense mechanisms. Methods: The skin and oral microbiome of CMC and HIES patients was compared to that of healthy controls at five body sites using 16S rRNA sequencing. The influence of skin colonizers on the immune response was investigated using in vitro experiments. Results: The microbiome of CMC and HIES patients contained more Gram-negative bacteria, especially Acinetobacter spp., and less of the normal Corynebacterium spp. compared to healthy controls. Exposure of human primary leukocytes to Acinetobacter suppressed the cytokine response to Candida albicans and S. aureus, while the normal corynebacteria did not suppress cytokine responses. Discussion: These results demonstrate that central mediators of immune responses like STAT1 and STAT3 not only directly influence immune responses, but also result in changes in the skin microbiome that in turn can amplify the defective immune response against fungal and microbial pathogens.
No differences in morphology, epidermal stratification, and expression of proliferation (Ki67) and differentiation proteins (keratin 10, loricrin) were observed between unstimulated wild-type and ...STAT1 GOF mutation HEEs (Fig 1, A). Because keratinocytes are a source of antimicrobial proteins, we also stained for the antimicrobial protease inhibitor SKALP/elafinE12-E14 and for late cornified envelope 3 (LCE3) proteins, a recently discovered group of antibacterial epithelial proteins.6 SKALP/elafin was present at very low levels in HEEs of both genotypes, whereas LCE3 staining displayed the normal pattern in the upper epidermis. IFN-γ showed an antiproliferative effect on both genotypes, as witnessed by the absence of Ki67-positive cells. ...loricrin expression was reduced in IFN-γ–treated cultures of normal cells but was increased in patient cells, suggesting premature terminal differentiation. ...it opens up new treatment strategies for STAT1 GOF skin, namely, blocking IFN-γ signaling, which has been successful in several cases.8,9,E17 With hematological stem cell transplantation it might be possible to fully restore the CMC phenotype because the immune system might overcome any local defects in the skin. Tissue distribution of LCE3 suggests a possible link of these proteins with the infection predilection sites at the hands, feet, and oral cavity. ...these novel insights put forward another rationale to investigate JAK inhibitors in STAT1 GOF, because it might restore the local skin defects and thus has the potential to lead to clinical benefit.
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