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Biology subjects

Eming, S.

Publications and source records attributed to Eming, S..

4 recordsLinked to original sources

Persistent activation of STAT6 in keratinocytes elicits neutrophilic skin inflammation, pruritus and S. aureus colonization reminiscent of chronic atopic dermatitis

Atopic dermatitis (AD) evolves from initial type 2 immunity-driven inflammation to chronic mixed responses by poorly understood mechanisms. To investigate how the prolonged activation of the usually IL-4/IL-13-induced transcription factor STAT6 in keratinocytes impacts on the development and subtype of AD, we generated a new mouse model in which a constitutively active form of STAT6 is selectively expressed in keratinocytes. These K14Cre+STAT6vt/vt mice spontaneously developed AD-like skin lesions characterized by Staphylococcus aureus colonization, neutrophilic inflammation, and pruritus starting at the age of 12-14 weeks. Treatment with antibiotics mitigated pathology, indicating that it is microbiota-driven. Comparison of human AD gene expression data with the transcriptome of skin biopsies from K14Cre+STAT6vt/vt mice revealed features shared with chronic AD, including genes associated with neutrophil and keratinocyte activation. Furthermore, heterozygous K14Cre+STAT6vt/wt mice developed a mixed eosinophilic and neutrophilic skin inflammation with exacerbated pathology compared to wild-type controls in an induced model of atopic dermatitis, compatible with chronic AD. These results indicate that persistent STAT6 activity in keratinocytes facilitates S. aureus outgrowth on the skin, promotes a type 1-/type 3-biased immune response, and is sufficient to mimic the transition from acute type 2 immunity-to chronic type 1-/type 3-immunity-dominated AD.

immunology↗

Exploring mechanisms of scar-free skin wound healing in adult zebrafish in comparison to mouse

Adult zebrafish have the ability to perfectly regenerate their skin after injury without leaving a scar behind. Yet, they intermediately form a collagen-rich granulation tissue that later fully regresses. In contrast, adult mammals lose this ability, resulting in persistent tissue fibrosis and scarring. We performed single-cell RNA sequencing to better characterize the dynamics and heterogeneity of involved cell types during different stages of zebrafish cutaneous wound healing, focusing on macrophages and fibroblasts. Macrophage subclusters display pro- and/or anti-inflammatory/repair characteristics, and fibroblast subclusters characteristics of extracellular matrix formation and degradation, which largely co-exist during all stages of wound healing. Strikingly, some fibroblasts display signatures of myofibroblasts, implicated in fibrotic healing in mammals. In addition, zebrafish fibroblasts express multiple genes with described pro-fibrotic effects in mammalian models. One of them is plod2, which encodes lysylhydroxylase 2. In cutaneous mouse wounds, Plod2 is induced in fibroblasts by macrophage-released Resistin-like molecule RELM encoded by the Retlna gene, promoting the formation of DHLNL collagen crosslinks and thereby less resolvable fibrotic tissue. retln genes are absent from the zebrafish genome; nevertheless, plod2 expression is initiated in zebrafish dermal fibroblasts upon wounding, in this case via TGF{beta} signaling, accompanied by increased collagen DHLNL crosslinking. Yet, both transgenic overexpression and genetic knock-out of plod2 do not interfere with granulation tissue formation and regression, pointing to additional pathways assuring the resolution of transient fibrosis in zebrafish skin wounds even in the presence of strong collagen crosslinking.

developmental biology↗

Novel, postnatal manifestation of an epidermal barrier defect in a mouse model of isolated sulfite oxidase deficiency

Sulfite oxidase deficiency is a rare inborn error in metabolism leading to early childhood death due to rapidly progressing neurodegeneration. A new mouse model of sulfite oxidase deficiency carrying a homozygous deletion in the Suox gene resembles the human pathology in terms of neonatal death and elevation of sulfite and thiosulfate in plasma and urine, respectively. Homozygous Suox-/- mice are initially born healthy, display growth retardation starting at postnatal day 4 and die in average at day 9.6. Here we report that Suox-/- mice develop dry and scaly skin early postnatally, showing that sulfite oxidase is essential to maintain a functional skin barrier after birth. At postnatal day 5 Suox-/- mice develop altered epidermal morphology and dysregulated early and late keratinocyte differentiation accompanied by increased stress response. We propose a sulfite-induced cleavage of disulfide bonds in key epidermal proteins essential for a functional barrier.

biochemistry↗

Cleavage of cFLIP restrains cell death during viral infection and tissue injury and favors tissue repair

Cell death coordinates repair programs following pathogen attack and tissue injury. However, aberrant cell death can interfere with such programs and cause organ failure. cFLIP is a crucial regulator of cell death and a substrate of Caspase-8. Yet, the physiological role of cFLIP cleavage by Caspase-8 remains elusive. Here, we discovered an essential role for cFLIP cleavage in restraining cell death in different pathophysiological scenarios. Mice expressing a cleavage-resistant cFLIP mutant, CflipD377A, exhibited increased sensitivity to SARS-CoV-induced lethality, impaired skin wound healing and increased tissue damage caused by Sharpin deficiency. In vitro, abrogation of cFLIP cleavage sensitizes cells to TNF-induced necroptosis and apoptosis by favoring complex-II formation. Mechanistically, the cell death-sensitizing effect of the D377A mutation depends on Gln(Q)469. These results reveal a crucial role for cFLIP cleavage in controlling the amplitude of cell death responses occurring upon tissue stress, to ensure the execution of repair programs.

cell biology↗