2 research outputs found
Supplementary Material for: The Effects of Human Beta-Defensins on Skin Cells in vitro
<p><b><i>Background:</i></b> Defensins are antimicrobial peptides that
exert immunomodulatory and chemotactic functions. Based on these
properties and their high expression levels in the skin, they are likely
to affect skin inflammation, infection, and wound healing. This may
lead to therapeutic applications in (burn) wound healing. <b><i>Objective:</i></b>
We aimed to investigate the effects of human β-defensins (hBDs) on
keratinocytes and fibroblasts, 2 major skin cell types involved in skin
regeneration. <b><i>Methods:</i></b> Monolayer keratinocyte and
fibroblast cultures were exposed to recombinant hBDs, and we
overexpressed hBD2 and hBD3 in keratinocytes of reconstructed epidermal
equivalents by lentiviral transduction. The effects were measured by
immunohistochemistry, quantitative real-time PCR, and migration assays.
Kinome analyses were performed on cultured keratinocytes to investigate
the signal transduction events elicited by hBD stimulation. <b><i>Results:</i></b>
We found that hBD3 induced the expression of cytokines and chemokines
in keratinocytes, which was not observed in fibroblasts. hBD2, however,
stimulated cell migration only in fibroblasts, which was not found for
hBD3. Both defensins are likely to exert receptor-mediated effects in
keratinocytes, as witnessed by changes in protein kinase activation
following stimulation by hBD2 and hBD3. Kinome analysis suggested that
protein kinase C activation was a common event for both defensins. We
observed, however, considerable differences in keratinocyte responses
between stimulation by exogenous recombinant defensins and endogenous
defensins expressed following lentiviral transduction. <b><i>Conclusion:</i></b>
Defensins exert modest biological effects on skin cells that are
potentially beneficial in wound healing, but many questions regarding
the biological mechanisms of action and relevance for the in vivo
situation are still remaining.</p
Supplementary Material for: Skin Microbiome Imbalance in Patients with STAT1/STAT3 Defects Impairs Innate Host Defense Responses
<b><i>Background:</i></b> Chronic mucocutaneous candidiasis (CMC) and hyper-IgE syndrome (HIES) are primary immunodeficiencies mainly caused by mutations in <i>STAT1</i> and <i>STAT3</i>, respectively. CMC and HIES patients have an increased risk for skin and mucosal infections with fungal pathogens and <i>Staphylococcus aureus</i>. 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> The microbiome of CMC and HIES patients contained more Gram-negative bacteria, especially <i>Acinetobacter </i>spp.<i>,</i> and less of the normal <i>Corynebacterium </i>spp. compared to healthy controls. Exposure of human primary leukocytes to <i>Acinetobacter</i> suppressed the cytokine response to <i>Candida albicans </i>and <i>S. aureus,</i> while the normal corynebacteria did not suppress cytokine responses. <b><i>Discussion:</i></b> 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