Search results for "keratin"

Medium-term Culture of Normal Human Oral Mucosa: A Novel Three-dimensional Model to Study the Effectiveness of Drugs Administration

2012

Tissue-engineered oral mucosal equivalents have been developed for in vitro studies for a few years now. However, the usefulness of currently available models is still limited by many factors, mainly the lack of a physiological extracellular matrix (ECM) and the use of cell populations that do not reflect the properly differentiated cytotypes of the mucosa of the oral cavity. For this reason, we have developed a novel three-dimensional culture model reflecting the normal architecture of the human oral mucosa, with the main aim of creating a better in vitro model where to test cellular responses to drugs administration. This novel 3D cell culture model (3D outgrowth) was set up using an arti…

The α and β Subunits of the Metalloprotease Meprin Are Expressed in Separate Layers of Human Epidermis, Revealing Different Functions in Keratinocyte…

2007

The zinc endopeptidase meprin (EC 3.4.24.18) is expressed in brush border membranes of intestine and kidney tubules, intestinal leukocytes, and certain cancer cells, suggesting a role in epithelial differentiation and cell migration. Here we show by RT-PCR and immunoblotting that meprin is also expressed in human skin. As visualized by immunohistochemistry, the two meprin subunits are localized in separate cell layers of the human epidermis. Meprin alpha is expressed in the stratum basale, whereas meprin beta is found in cells of the stratum granulosum just beneath the stratum corneum. In hyperproliferative epidermis such as in psoriasis vulgaris, meprin alpha showed a marked shift of expre…

Genetic ablation of mast cells redefines the role of mast cells in skin wound healing and bleomycin-induced fibrosis.

2014

Conclusive evidence for the impact of mast cells (MCs) in skin repair is still lacking. Studies in mice examining the role of MC function in the physiology and pathology of skin regenerative processes have obtained contradictory results. To clarify the specific role of MCs in regenerative conditions, here we used a recently developed genetic mouse model that allows conditional MC ablation to examine MC-specific functions in skin. This mouse model is based on the cell type–specific expression of Cre recombinase in connective tissue–type MCs under control of the Mcpt5 promoter and the Cre-inducible diphtheria toxin receptor–mediated cell lineage ablation by diphtheria toxin. In response to ex…

Potential Antipsoriatic Avarol Derivatives as Antioxidants and Inhibitors of PGE2 Generation and Proliferation in the HaCaT Cell Line

2004

The synthesis and structure-activity relationships for a series of 14 new avarol derivatives as antioxidants and inhibitors of cell proliferation and PGE(2) generation in human keratinocytes are described. Compound 6 (thiosalicylic derivative) was the most potent inhibitor of superoxide generation in human neutrophils and also potently inhibited PGE(2) generation in the human keratinocyte HaCaT cell line. Compound 7(3'-methylaminoavarone) presented the best antiproliferative profile, by the inhibition of (3)H-thymidine incorporation in HaCaT cells, with potency similar to the reference compound anthralin. None of the avarol derivatives showed any sign of cytotoxicity measured as LDH release…

Differential role of p38 mitogen activated protein kinase for cellular recovery from attack by pore-forming S. aureus alpha-toxin or streptolysin O.

2006

Following the observation that cells are able to recover from membrane lesions incurred by Staphylococcus aureus alpha-toxin and streptolysin O (SLO), we investigated the role of p38 in this process. p38 phosphorylation occurred in response to attack by both toxins, commencing within minutes after toxin treatment and waning after several hours. While SLO reportedly activates p38 via ASK1 and ROS, we show that this pathway does not play a major role for p38 induction in alpha-toxin-treated cells. Strikingly divergent effects of p38 blockade were noted depending on the toxin employed. In the case of alpha-toxin, inhibition of p38 within the time frame of its activation led to disruption of th…

Induction of Cell Differentiation in Transformed Keratinocytes by Synthetic (Glyco)peptides from the Homophilic Recognition Domain of E-Cadherin

2002

Exosomes released by keratinocytes modulate melanocyte pigmentation

2015

Cells secrete extracellular vesicles (EVs), exosomes and microvesicles, which transfer proteins, lipids and RNAs to regulate recipient cell functions. Skin pigmentation relies on a tight dialogue between keratinocytes and melanocytes in the epidermis. Here we report that exosomes secreted by keratinocytes enhance melanin synthesis by increasing both the expression and activity of melanosomal proteins. Furthermore, we show that the function of keratinocyte-derived exosomes is phototype-dependent and is modulated by ultraviolet B. In sum, this study uncovers an important physiological function for exosomes in human pigmentation and opens new avenues in our understanding of how pigmentation is…

Sun exposure and PDZK1 genotype modulate PDZK1 gene expression in normal skin

2020

Human skin pigmentation results from the enzymatically controlled synthesis of melanin pigments in specialized organelles (melano‐somes) produced within epidermal melanocytes, followed by their transfer to neighboring keratinocytes and their distribution through‐out the epidermis.1 Constitutive skin pigmentation seems to be mostly genetically determined,2 being altered by numerous intrinsic and extrinsic factors affecting the epidermal melanin unit

Potential antipsoriatic effect of chondroitin sulfate through inhibition of NF-κB and STAT3 in human keratinocytes

2012

Abstract Chondroitin sulfate (CS) is a natural glycosaminoglycan, formed by the 1–3 linkage of d -glucuronic acid to N-acetylgalactosamine, present in the extracellular matrix. It is used as a slow acting disease modifying agent in the treatment of osteoarthritis, and part of its beneficial effects are due to its antiinflammatory properties that result from an inhibitory effect on NF-κB signaling pathway. This ability raises the hypothesis that CS might be effective in other chronic inflammatory processes such as psoriasis, in which a deregulation of NF-κB is a key feature. In addition, psoriasis is characterized by an upregulation of STAT3 signaling pathway that is related to the epidermal…

Studies of Jak/STAT3 expression and signalling in psoriasis identifies STAT3-Ser727 phosphorylation as a modulator of transcriptional activity

2013

Jak/Tyk proteins have recently aroused as possible therapeutic targets for the treatment of psoriasis. In psoriasis, these proteins signal through STAT molecules including STAT3, and STAT3 expression and activation has been shown augmented in psoriatic lesions. Here, we characterized the expression of Jak/Tyk proteins in lesional compared with non-lesional psoriatic skin. Jak1, Jak2 mRNA and protein and Tyk2 mRNA appeared to be downregulated, whereas Jak3 mRNA expression was increased. Moreover, STAT3 expression and activation was examined in psoriasis. STAT3 is activated at two phosphorylation sites: Tyr705 and Ser727. Both phosphorylation sites were phosphorylated in lesional psoriatic sk…