| 1. |
- Forsberg, Sofi, et al.
(författare)
-
Comparison of growth-inhibitory agents by fluorescence imaging of human skin re-epithelialization in vitro
- 2006
-
Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 86:4, s. 292-299
-
Tidskriftsartikel (refereegranskat)abstract
- Drug screening procedures should preferably utilize experimental settings mimicking the in vivo situation. The aim of this study was to evaluate a skin explant model as a tool to identify topical agents with anti-proliferative properties in human epidermis. Re-epithelialization was initiated from a skin punch biopsy explanted onto de-epidermized dermis and cultured at the air-liquid interface in the presence of the epidermal growth factor receptor kinase inhibitor PKI166, tacrolimus or established topical anti-psoriatic drugs: betamethasone, calcipotriol, dithranol and tazarotene. Neo-epidermal extension was traced by fluorescence microscopy prior to histomorphometric analysis. PKI166 at 1 mu M decreased the mean radial outgrowth rate (-19%), frequency of BrdU-positive (-37%) and laminin 5-positive (-45%) cells, indicating reduced proliferation and migration of neo-epidermal keratinocytes. However, the papillomatosis index and epithelial thickness were not significantly affected. Calcipotriol at 1 mu M had a similar effect on the outgrowth rate (-15%) and fraction of laminin 5-stained keratinocytes (-40%). Furthermore, calcipotriol significantly reduced mean neo-epidermal thickness. Equimolar concentrations of the other test compounds had no apparent effect on histology or outgrowth parameters. This study exemplifies the versatility of combined dynamic and morphological analysis and emphasizes the potential of epidermal growth factor receptor-directed inhibition in hyperproliferative disorders of the epidermis.
|
|
| 2. |
- Forsberg, Sofi, 1980-
(författare)
-
Human Epidermal Growth Factor Receptors and Biological Effects of HER-directed Molecules on Skin Epithelialization
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human skin forms a biologically active barrier and maintains vital protective functions through continuous regeneration of cells within its outermost layer, the epidermis. In healthy skin, renewal of epithelial cells is a tightly regulated process in which the epidermal growth factor receptor (EGFR or HER1) and its various ligands are involved. The biological role of other EGFR family members (HER2–4) in normal and diseased human skin has gained less interest. The purpose of this work was to investigate the expression and contribution of different HERs in cultured epidermis and psoriatic skin. Epidermal regeneration was studied by fluorescence imaging of a skin explant model exposed to anti-psoriatic drugs, HER ligands or HER-blocking molecules. EGFR, HER2 and HER3 were all markedly expressed with an in vivo-like immunostaining pattern in cultured neoepidermis, whereas only low amounts of HER4 were detected at protein and mRNA levels. Re-epithelialization was associated with receptor activation. Application of HER-selective tyrosine kinase inhibitors and monoclonal antibodies reduced the proliferative activity, receptor phosphorylation and radial outgrowth from normal skin explants. Similar anti-dynamic effects were obtained with HER kinase inhibition of neoepidermis generated from psoriatic skin. Among the HER receptors, EGFR seemed to be the dominant subtype during epithelialization in vitro although HER2 and HER3 were also involved. HER2 probably functioned as a co-receptor for the kinase-deficient HER3 in neoepidermis. In vivo, expression of HER4 mRNA was detected in normal and uninvolved psoriatic skin but was virtually absent in lesional skin, a potentially important finding for HER signalling in psoriasis. This thesis demonstrates the utility of combined dynamic and biochemical analyses of re-epithelialization and highlights the role of EGFR and other HERs for epidermal growth. It also underscores the potential of HER-directed inhibition to control hyperproliferative states of the epidermis.
|
|
| 3. |
- Forsberg, Sofi, et al.
(författare)
-
Regeneration of human epidermis on acellular dermis is impeded by small-molecule inhibitors of EGF receptor tyrosine kinase
- 2008
-
Ingår i: Archives of Dermatological Research. - : Springer Science and Business Media LLC. - 0340-3696 .- 1432-069X. ; 300:9, s. 505-516
-
Tidskriftsartikel (refereegranskat)abstract
- The family of human epidermal growth factor receptors (EGFR, HER2-4) exerts key functions in normal and malignant epithelial cells. Both EGFR and HER2 are valuable targets for anti-cancer drugs by interfering with ligand binding, receptor dimerization, or tyrosine kinase activity. A similar therapeutic strategy has been advocated for chronic psoriasis since plaque lesions overexpress EGFR and its ligands. Our aim was to characterize EGFR/HER2 protein expression in skin cultures and to evaluate the effects of tyrosine kinase inhibitors on epidermal outgrowth, morphology, and EGFR activation. Human skin explants were established on cell-free dermis and cultured at the air-liquid interface. The impact of small-molecule HER inhibitors on outgrowth was assayed by fluorescence-based image analysis and histometry. Effects of a dual EGFR/HER2 kinase inhibitor, PKI166, on neoepidermis were studied by immunohistochemistry and Western blot. Receptor immunostaining showed in vivo-like distributions with highest EGFR intensity in the proliferative layers whereas HER2 was mainly expressed by suprabasal keratinocytes. Reepithelialization was associated with EGFR autophosphorylation irrespective of exogenous ligand stimulation. PKI166 inhibited neoepidermal EGFR activation, keratinocyte proliferation, and outgrowth from normal and psoriatic skin explants. The rate of epidermalization in presence of other HER inhibitors varied suggesting that drug specificity, potency, and reversibility determine the dynamic outcome. Overall, agents predominantly targeting EGFR kinase were more efficient inhibitors of epidermal regeneration than an HER2-selective drug. The study illustrates the usefulness of a dynamic skin model and emphasizes the potential of HER-directed approaches to control epidermal growth in hyperproliferative skin disorders.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Skoog, Tiina, et al.
(författare)
-
Matrix metalloproteinase-21 expression is associated with keratinocyte differentiation and upregulated by retinoic acid in HaCaT cells
- 2009
-
Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 129:1, s. 119-30
-
Tidskriftsartikel (refereegranskat)abstract
- In the skin, expression of several matrix metalloproteinases (MMPs) occurs in response to tissue injury, tumorigenesis, angiogenesis, apoptosis, and inflammation. The recently cloned MMP-21 has been implicated in skin development and various epithelial cancers. In this study, we found that it is also expressed by differentiated keratinocytes (KCs) in various benign skin disorders, in which it was not associated with KC apoptosis or proliferation, and in organotypic cultures. Furthermore, MMP-21 was induced in keratinocytes in association with increased calcium and presence of the differentiation marker filaggrin. In stably transfected A431 and HEK293 cell lines, MMP-21 increased invasion of cells but did not associate with increased apoptosis, proliferation, or epithelial-to-mesenchymal transition. Of various agents tested in HaCaT cell cultures, only retinoic acid (10(-6) M) and staurosporine (2.5 x 10(-8) M) upregulated MMP-21 mRNA and protein expression, whereas tumor promoters, hormones, or dexamethasone were without effect. Our results suggest that MMP-21 may be an important protease in the terminal differentiation of keratinocytes.
|
|
| 7. |
- Tiala, Inkeri, et al.
(författare)
-
The PSORS1 locus gene CCHCR1 affects keratinocyte proliferation in transgenic mice
- 2008
-
Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 17:7, s. 1043-1051
-
Tidskriftsartikel (refereegranskat)abstract
- The CCHCR1 gene (Coiled-Coil alpha-Helical Rod protein 1) within the major psoriasis susceptibility locus PSORS1 is a plausible candidate gene for the risk effect. We have previously generated transgenic mice overexpressing either the psoriasis-associated risk allele CCHCR1*WWCC or the normal allele of CCHCR1. All transgenic CCHCR1 mice appeared phenotypically normal, but exhibited altered expression of genes relevant to the pathogenesis of psoriasis, including upregulation of hyperproliferation markers keratins 6, 16 and 17. Here, we challenged the skin of CCHCR1 transgenic mice with wounding or 12-O-tetradecanoyl-13-acetate (TPA), treatments able to induce epidermal hyperplasia and proliferation that both are hallmarks of psoriasis. These experiments revealed that CCHCR1 regulates keratinocyte proliferation. Early wound healing on days 1 and 4 was delayed, and TPA-induced epidermal hyperproliferation was less pronounced in mice with the CCHCR1*WWCC risk allele than in mice with the normal allele or in wild-type animals. Finally, we demonstrated that overexpression of CCHCR1 affects basal keratinocyte proliferation in mice; CCHCR1*WWCC mice had less proliferating keratinocytes than the non-risk allele mice. Similarly, keratinocytes isolated from risk allele mice proliferated more slowly in culture than wild-type cells when measured by BrdU labeling and ELISA. Our data show that CCHCR1 may function as a negative regulator of keratinocyte proliferation. Thus, aberrant function of CCHCR1 may lead to abnormal keratinocyte proliferation which is a key feature of psoriatic epidermis.
|
|
