Induction of Inflammatory Cytokines by a Keratin Mutation and their Repression by a Small Molecule in a Mouse Model for EBS

Epidermolysis bullosa simplex (EBS) is a skin disorder caused by mutations in keratin (K) 5 or K14 genes. It is widely regarded as a mechanobullous disease, resulting from a weakened cytoskeleton, causing extensive cytolysis. It was postulated by others that certain K14 mutations induce tumor necrosis factor-α (TNF-α) and increase apoptosis. Here, we report that in K5−/− mice and in a cell culture model of EBS, the mRNA and protein levels of TNF-α remain unaltered. Transcriptome analysis of K5−/− mice revealed, however, that the proinflammatory cytokines IL-6 and IL-1β were significantly upregulated at the mRNA level in K5−/− mouse skin. These results were confirmed by TaqMan real-time PCR and ELISA assays. We hypothesize that keratin mutations contribute to EBS in a mouse model by inducing local inflammation that mediates a stress response. Following clinical reports, we applied the small molecule doxycycline to K5−/− mice. We demonstrate that doxycycline extended the survival of neonatal K5−/− mice from less than 1 to up to 8hours. Microarray and TaqMan real-time PCR showed a downregulation of matrix metalloproteinase 13 and IL-1β, indicating an effect of doxycycline on transcription. Our data offer a novel small molecule-based therapy approach for EBS

A Disintegrin and Metalloprotease (ADAM): Historical Overview of Their Functions

Since the discovery of the first disintegrin protein from snake venom and the following identification of a mammalian membrane-anchored metalloprotease-disintegrin implicated in fertilization, almost three decades of studies have identified additional members of these families and several biochemical mechanisms regulating their expression and activity in the cell. Most importantly, new in vivo functions have been recognized for these proteins including cell partitioning during development, modulation of inflammatory reactions, and development of cancers. In this review, we will overview the a disintegrin and metalloprotease (ADAM) family of proteases highlighting some of the major research achievements in the analysis of ADAMs' function that have underscored the importance of these proteins in physiological and pathological processes over the years

Fibrillin microfibrils and proteases, key integrators of fibrotic pathways

Supramolecular networks composed of multi-domain ECM proteins represent intricate cellular microenvironments which are required to balance tissue homeostasis and direct remodeling. Structural deficiency in ECM proteins results in imbalances in ECM-cell communication resulting often times in fibrotic reactions. To understand how individual components of the ECM integrate communication with the cell surface by presenting growth factors or providing fine-tuned biomechanical properties is mandatory for gaining a better understanding of disease mechanisms in the quest for new therapeutic approaches. Here we provide an overview about what we can learn from inherited connective tissue disorders caused primarily by mutations in fibrillin-1 and binding partners as well as by altered ECM processing leading to defined structural changes and similar functional knock-in mouse models. We will utilize this knowledge to propose new molecular hypotheses which should be tested in future studies. (C) 2018 Elsevier B.V. All rights reserved

Metalloproteinases in melanoma

Tumour cell adhesion, motility, proteolytic activities and cell receptors have important roles in cancer invasion. These processes are involved from early development of melanoma within the epidermis, to tumour cell invasion of the underlying tissue until intravasation of lymphatic or blood vessels, and thereafter, dissemination into distant organs occur. The activity of several proteolytic enzymes was shown to be pivotal in promoting melanoma cell invasion. These enzymes not only remodel the extracellular matrix, but also release active factors and shed cell surface receptors thereby mediating melanoma cross-communication with their microenvironment. This leads to the generation of a favourable environment for melanoma growth. Several proteases are involved in melanoma invasion and include serine, cysteine proteases, matrix metalloproteases (MMPs) and the disintegrin and metalloproteases (ADAMs). This study summarises the current knowledge on the role of metalloproteinases, MMPs and ADAMs, in melanoma. (C) 2014 Elsevier GmbH. All rights reserved

Metalloproteinases in dermal homeostasis

Maintenance of skin homeostasis is a highly regulated and complex process involving a continuous remodeling by several extracellular matrix proteases, including metalloproteinases. The expression and activity of all metalloproteinases are under strict control, and their deregulation is often associated with diseases or chronic conditions, thereby being considered popular targets for developing new therapeutics. This review will highlight metalloproteinases of the MMP and ADAM families with functions in dermal homeostasis and give some insights into the mechanisms regulating their activity and expression. Furthermore, we discuss how the dysregulation of the most prominent family members affects dermal homeostasis by triggering disease development and influencing progression, focusing on cancer and aging. Here, recent discoveries and new approaches that target or exploit metalloproteinase activity in therapy are emphasized. The potential of naturally derived components in regulating metalloproteinase expression and activity in disease is discussed

Epidermal NLRP10 contributes to contact hypersensitivity responses in mice

The nucleotide binding and oligomerization domain-like receptor (NLR) protein NLRP10 is highly expressed in the epidermis and contributes to cell-autonomous responses against invasive bacteria. To investigate the role of NLRP10 in inflammatory responses of the skin we analyzed the effect of full-body and keratinocyte-specific depletion of NLRP10 in croton oil-induced irritant contact dermatitis (ICD) and 1-fluoro-2,4-dinitrobenzene (DNFB)-induced contact hypersensitivity (CHS) in mice. Nlrp10(-/-) mice were phenotypically normal and skin repair after woundingwas not affected by lack of NLRP10. Similarly, we did not detect a contribution of NLRP10 to the ICD response induced by croton oil. In contrast, Nlrp10(-/-) mice showed significantly reduced inflammation in the DNFB-induced CHS response as compared to control animals. Microscopic analysis revealed significantly reduced numbers of CD4(+) and CD8(+) T cells in the infiltrates of animals lacking NLRP10 expression after CHS challenge. Epidermis-specific deletion of Nlrp10 by keratin-14 promotor driven Cre-recombinase was sufficient to account for this phenotype, although lymphocyte recruitment seemed to be unaltered in animals lacking NLRP10 expression in keratinocytes. Taken together, we provide evidence that NLRP10 contributes to T-cell-mediated inflammatory responses in the skin and highlight a physiological role of NLRP10 in epidermal keratinocytes