Search results for "Integumentary system"
showing 10 items of 744 documents
Baicalin and berberine ultradeformable vesicles as potential adjuvant in vitiligo therapy.
2018
0.5-1% of the world's population is affected by vitiligo, a disease characterized by a gradual depigmentation of the skin. Baicalin and berberine are natural compounds with beneficial activities, such as antioxidant, anti-inflammatory and proliferative effects. These polyphenols could be useful for the treatment of vitiligo symptoms, and their efficacy can be improved by loading in suitable carriers. The aim of this work was to formulate and characterize baicalin or berberine loaded ultradeformable vesicles, and demonstrate their potential as adjuvants in the treatment of vitiligo. The vesicles were produced using a previously reported simple, scalable method. Their morphology, size distrib…
Do nonmelanoma skin cancers develop from extra-cutaneous stem cells?
2008
A hypothesis is presented that nonmelanoma skin cancers can develop from extra-cutaneous stem cells, and not exclusively from skin keratinocytes. This idea is supported by recent findings regarding the initiation of cancers in the digestive tract, and by a cancer stem cell model of a neoplasia. It is known that multipotent adult progenitor cells can trans-differentiate into very diverse cellular lineages and can be recruited to areas of profound tissue injury. In these settings, they might also initiate malignant transformation. Some epidemiological data and recent findings regarding mechanisms of wound healing indicate that skin cancers could also originate from bone marrow-derived or othe…
Resealing of large transmembrane pores produced by streptolysin O in nucleated cells is accompanied by NF‐κB activation and downstream events
2001
Streptolysin O (SLO), archetype of a cholesterol-binding bacterial cytolysin, forms large pores in the plasma membrane of mammalian cells. We have recently reported that when a limited number of pores are generated in a cell, they can be sealed in a Ca++-dependent process. Here, we show that resealing is followed by the release of IL-6 and IL-8 from keratinocytes and from endothelial cells, both relevant targets for SLO attack. Production of cytokines by these cells was preceded by activation of transcription factor nuclear factor kappaB, which thus emerges as a common denominator of stress responses to various pore-forming agents, including alpha-toxin of Staphylococcus aureus and compleme…
Delayed healing of chronic leg ulcers can result from impaired trafficking of bone marrow-derived precursors of keratinocytes to the skin
2006
In this paper, it is hypothesized that in chronic wounds the process of homing of bone marrow-derived precursors of keratinocytes is disturbed, and that the interaction between cutaneous T-cell attracting chemokine (CTACK/CCL27) and soluble P-selectin glycoprotein ligand-1 (PSGL-1) can be the cause of this impairment. Several studies have revealed that bone marrow-derived cells (BMDC) trans-differentiate into various cellular lineages, and probably they participate also in healing of wounded skin. Recent studies have demonstrated that BMDC can engraft into the epidermis, and probably they do not engraft into epidermis as keratinocyte stem cells, but rather as transient amplifying cells. So,…
Cannabinoid 1 Receptors in Keratinocytes Modulate Proinflammatory Chemokine Secretion and Attenuate Contact Allergic Inflammation
2013
Abstract Epidermal keratinocytes (KCs) and cannabinoid (CB) receptors both participate in the regulation of inflammatory responses in a mouse model for allergic contact dermatitis, the contact hypersensitivity (CHS) response to the obligate sensitizer 2,4-dinitrofluorobenzene. In this study, we investigated the cellular and molecular mechanisms how CB1 receptors attenuate CHS responses to 2,4-dinitrofluorobenzene. We used a conditional gene-targeting approach to identify the relative contribution of CB1 receptors on epidermal KCs for the control of CHS responses. To determine the underlying cellular and molecular mechanisms that regulate inflammatory responses in the effector phase of CHS, …
Cellular and molecular mechanisms in the induction phase of contact sensitivity.
1995
During the induction phase of contact sensitivity, hapten-specific Th1 cells are primed by epidermal Langerhans cells. These Langerhans cells present hapten on MHC class II molecules and provide costimulatory signals. This presentation discusses the induction of cytokines in Langerhans cells and keratinocytes by haptens and their regulatory effects on contact sensitivity. Haptens were painted on the skin of normal BALB/c mice and epidermal cells were prepared at various times thereafter. Langerhans cell-derived interleukin (IL)-1 beta mRNA was observed as early as 15 min after hapten paining. In keratinocytes, tumor necrosis factor-alpha, IL-1 alpha, IP-10, MIP-2 and IL-10 were found to be …
α-parvin is required for epidermal morphogenesis, hair follicle development and basal keratinocyte polarity
2020
Epidermal morphogenesis and hair follicle (HF) development depend on the ability of keratinocytes to adhere to the basement membrane (BM) and migrate along the extracellular matrix. Integrins are cell-matrix receptors that control keratinocyte adhesion and migration, and are recognized as major regulators of epidermal homeostasis. How integrins regulate the behavior of keratinocytes during epidermal morphogenesis remains insufficiently understood. Here, we show that alpha-parvin (alpha-pv), a focal adhesion protein that couples integrins to actin cytoskeleton, is indispensable for epidermal morphogenesis and HF development. Inactivation of the murine alpha-pv gene in basal keratinocytes res…
Epidermal Cells Enhance Interleukin 4 and Immunoglobulin E Production After Stimulation with Protein Allergen
1996
Exposure to certain allergens via epithelial tissues is the primary route for tile induction of immunoglobulin E–dependent allergies of the immediate type associated with atopic diseases. In order to address the question whether and how epithelial cells might contribute to the induction or increase of T H2 -dependent IgE production, we performed co-culture experiments of syngeneic epidermal cells and cells from the associated lymphoid tissue or spleen (responder cells) of BALB/c mice primed with ovalbumin in vivo . In the presence of ovalbumin in vitro , immunoglobulin E but not immunoglobulin G 2a production was significantly enhanced by the addition of epidermal cells, and separation of e…
In contrast to their murine counterparts, normal human keratinocytes and human epidermoid cell lines A431 and HaCaT fail to express IL-10 mRNA and pr…
1997
Abstract In mice, keratinocyte-derived IL-10 is up-regulated by ultraviolet-B (UVB) radiation and plays a major role in UVB-induced immunosuppression. The present study was designed to examine whether a comparable phenomenon can be detected in man. Freshly isolated or cultured normal human keratinocytes (NHK) and keratinocyte cell lines A431 and HaCaT were stimulated with graded doses of UVB (up to 200 J/m2) or with a variety of other stimuli. RNA was extracted at various time points post-stimulation and analysed by reverse transcriptase-polymerase chain reaction (RT-PCR) using four different IL-10-specific primer pairs and RNA from monocytes or T cells as positive controls. We failed to de…
Epidermolysis Bullosa Simplex-Type Mutations Alter the Dynamics of the Keratin Cytoskeleton and Reveal a Contribution of Actin to the Transport of Ke…
2003
Dominant keratin mutations cause epidermolysis bullosa simplex by transforming keratin (K) filaments into aggregates. As a first step toward understanding the properties of mutant keratins in vivo, we stably transfected epithelial cells with an enhanced yellow fluorescent protein-tagged K14R125C mutant. K14R125C became localized as aggregates in the cell periphery and incorporated into perinuclear keratin filaments. Unexpectedly, keratin aggregates were in dynamic equilibrium with soluble subunits at a half-life time of <15 min, whereas filaments were extremely static. Therefore, this dominant-negative mutation acts by altering cytoskeletal dynamics and solubility. Unlike previously post…