| 1. |
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| 2. |
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| 3. |
- Andersson, Eva, 1946-, et al.
(författare)
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Differential effects of UV irradiation on nuclear retinoid receptor levels in cultured keratinocytes and melanocytes
- 2003
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Ingår i: Experimental dermatology. - : Wiley. - 0906-6705 .- 1600-0625. ; 12:5, s. 563-71
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Tidskriftsartikel (refereegranskat)abstract
- A major risk factor for skin cancer is UV irradiation, which not only damages DNA and other photosensitive compounds like vitamin A, but may also perturb cellular signaling, e.g. via the retinoid receptor system believed to be important for cancer protection. We used cultured normal human keratinocytes and melanocytes to examine the effects of UV irradiation on the expression of the predominant retinoid receptors in the human skin (RARalpha, RARgamma and RXRalpha) and the AP-1 protein c-Jun; mRNA levels were studied by real-time PCR and protein levels by Western blot. In keratinocytes, a single dose of UVB (50 mJ/cm2) caused a rapid drop in the expression of all three receptors (mRNA levels minus 35-50% after 4 h; protein levels minus 20-45% after 8 h), which was followed over the next 40 h by a variable response, leading to full normalization for RARalpha only. In contrast, the levels of c-Jun did not change significantly after UV exposure. In melanocytes, UVB caused a similar drop of the retinoid receptor levels as in keratinocytes but this was soon followed by an increased expression leading to a complete normalization of all receptor levels within 1-3 days. The c-Jun levels in melanocytes increased 1 day after UV exposure and remained high (plus 50%) thereafter. In both cell types, a approximately 3-fold increase in apoptosis (measured by DNA fragmentation) was observed 8-48 h after UVB irradiation. In conclusion, a depletion of vitamin A and retinoid receptors by UV irradiation, together with unchanged or even increased c-Jun levels, might seriously interfere with retinoid signaling and thus promote future tumor development, especially in keratinocytes.
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| 4. |
- Andersson, Eva, et al.
(författare)
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Differential effects of UV irradiation on the nuclear retinoid receptor levels of cultured keratinocytes and melanocytes
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Skin cancer is the most common malignancy in man. A major risk factor is UV irradiation, which not only damages DNA but may also perturb cellular signaling, e.g. via the retinoid receptor system believed to be important for cancer protection. We used cultured normal human keratinocytes and melanocytes to study the effects of UV radiation on the expression of the retinoid receptors RARα, RARβ, RARγ and RXRα. By real-time PCR and Western blot technique, the mRNA and protein levels were monitored, before and up to 4 days following 50 mJ/cm2 UVB. In keratinocytes, UVB caused a rapid drop in all four mRNA levels (minus 50-70% the first 8 h) and protein levels dropped by 30-40% followed by a gradual increase, but full normalization was ouly reached for RARα within the study period. ln melanocytes, UVB caused a quick drop both in the receptor mRNA and protein levels (minus 50-60% after 4 h), followed by normalization of the protein levels for all receptors within 2-3 days. The UV-induced depletion of vitamin A and retinoid receptors might abrogate the retinoid signaling, which subsequently might promote tumor development.
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| 5. |
- Andersson, Eva, et al.
(författare)
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The metabolism of vitamin A to 3,4-didehydroretinol can be demonstrated in human keratinocytes, melanoma cells and HeLa cells, and is correlated to cellular retinoid-binding protein expression
- 1994
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Ingår i: Biochimica et Biophysica Acta. Molecular Cell Research. - : Elsevier BV. - 0167-4889 .- 1879-2596. ; 1224:3, s. 349-354
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Tidskriftsartikel (refereegranskat)abstract
- Conversion of retinol to 3,4-didehydroretinol is probably a rate-limiting step in the formation of 3,4-didehydroretinoic acid, a candidate ligand for nuclear retinoid receptors in human epidermal keratinocytes. To investigate whether this metabolic pathway also exists in other cell systems, we compared the retinoid concentrations and the bioconversion of [3H]retinol to [3H]3,4-didehydroretinol in human primary keratinocytes, human cervical carcinoma (HeLa) cells, human melanoma (JKM86-4) cells, monkey kidney epithelium (CV-1) cells, and murine teratocarcinoma (F9) cells. The cellular retinol concentration ranged from 2.33 to 99.1 pmol/mg protein with the highest values observed in keratinocytes. 3,4-Didehydroretinol was only detected in cells of human origin and its concentration ranged from 0.24 pmol/mg in HeLa to 34.6 pmol/mg in the keratinocytes. Incubation with [3H]retinol for 1–24 h resulted in a rapid appearance of [3H]3,4-didehydroretinol in human keratinocytes, and to a lesser extent in HeLa and melanoma cells, but not in the other cells. Analysis of cellular retinol- and retinoic acid-binding protein concentrations showed a correlation to the cells' ability to accumulate 3,4-didehydroretinol, suggesting a role for these proteins in the 3,4-didehydro metabolic pathway. The combined results suggest that although 3,4-didehydroretinol is most typical for human keratinocytes, studies of its metabolism are also feasible in HeLa cells which contain low levels of retinoid-binding proteins.
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| 6. |
- Andersson, Eva, 1946-, et al.
(författare)
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Ultraviolet irradiation depletes cellular retinol and alters the metabolism of retinoic acid in cultured human keratinocytes and melanocytes
- 1999
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Ingår i: Melanoma research. - 0960-8931 .- 1473-5636. ; 9:4, s. 339-346
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Tidskriftsartikel (refereegranskat)abstract
- Vitamin A is an intrinsic modulator of proliferation and differentiation in human epidermis, and may be destroyed by ultraviolet radiation (UVR) impinging on the skin. To identify the deleterious effects of a perturbed cellular vitamin A status, we investigated the endogenous retinoid concentrations and the metabolism of [3H]retinol and all-trans [3H]retinoic acid in cultured human keratinocytes and melanocytes exposed to UVR, using high performance liquid chromatography. Before UVR the retinoid content was similar in keratinocytes and melanocytes, but the uptake of [3H]retinol was three-fold higher and the uptake of [3H]retinoic acid was 10-fold higher in the melanocytes. In both cell types, UVR (UVA 360 mJ/cm2 plus UVB 140 mJ/cm2) instantaneously reduced the concentration of retinol by about 50% and that of 3,4-didehydroretinol by about 20%. The retinoid concentrations returned to normal within 1-2 days post-irradiation, despite there being no overt increase in the uptake of [3H]retinol or the biosynthesis of 3,4-didehydroretinol. However, in both types of irradiated cells, the accumulation of the biologically most active metabolite, all-trans [3H]retinoic acid, was about 60% higher than in control cells. Furthermore, the metabolism of authentically supplied [3H]retinoic acid was reduced, especially in irradiated keratinocytes, which probably contributed to the restoration of retinoid levels after UV exposure.
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| 7. |
- Andersson, Eva, et al.
(författare)
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β-Carotene Uptake and Bioconversion to Retinol Differ Between Human Melanocytes and Keratinocytes
- 2001
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Ingår i: Nutrition and Cancer. - 0163-5581 .- 1532-7914. ; 39:2, s. 300-306
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Tidskriftsartikel (refereegranskat)abstract
- β-Carotene is one of the carotenoids that has been considered to play a role in the natural defense against ultraviolet-induced skin cancer. It is not known whether epidermal cells are able to accumulate β-carotene and, subsequently, convert it to vitamin A. We used normal cultured human keratinocytes and melanocytes to study the uptake, and possible bioconversion to retinol, of authentic or [14C]β-carotene. The uptake was much higher in melanocytes than in keratinocytes, corresponding to a fivefold difference in the intracellular fraction after two days of incubation. An increased level of cellular retinol was noted after one day of β-carotene incubation. The conversion of [C]β-carotene to [14C]retinol peaked at 24 hours of incubation in keratinocytes and melanocytes. The results suggest that β-carotene can function as a local supply of vitamin A in the skin and that melanocytes are especially likely to store β-carotene.
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| 8. |
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| 9. |
- Bondeson, Marie-Louise, et al.
(författare)
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Connexin 26 (GJB2) mutations in two Swedish patients with atypical Vohwinkel (mutilating keratoderma plus deafness) and KID syndrome both extensively treated with acitretin
- 2006
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 86:6, s. 503-508
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Tidskriftsartikel (refereegranskat)abstract
- Neuroectodermal syndromes involving the skin and inner ear may be associated with mutations in connexin proteins, which form gap junctions important for intercellular communication. Vohwinkel syndrome (keratodermia mutilans with hearing loss) and keratitis-ichthyosis-deafness (KID) syndrome are rare ectodermal dysplasias associated with dominant mutations in the GJB2 gene encoding connexin 26. We report here two patients, one with KID and one with Vohwinkel syndrome. Both displayed unusual clinical features and responded well to long-term treatment with oral retinoid. Mutation analysis revealed a novel GJB2 mutation p.Gly59Ser in the patient with Vohwinkel syndrome, whereas a recurrent mutation (p.Asp50Asn) was found in the patient with KID syndrome. The clinical features, particularly a proneness to skin cancer in the patient with Vohwinkel syndrome, are discussed in relation to the identified genotypes.
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| 10. |
- Bornholdt, Dorothea, et al.
(författare)
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Genotype-Phenotype Correlations Emerging from the Identification of Missense Mutations in MBTPS2
- 2013
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 34:4, s. 587-594
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Tidskriftsartikel (refereegranskat)abstract
- Missense mutations affecting membrane-bound transcription factor protease site 2 (MBTPS2) have been associated with Ichthyosis Follicularis with Atrichia and Photophobia (IFAP) syndrome with or without BRESHECK syndrome, with keratosis follicularis spinulosa decalvans, and Olmsted syndrome. This metalloprotease activates, by intramembranous trimming in conjunction with the protease MBTPS1, regulatory factors involved in sterol control of transcription and in cellular stress response. In this study, 11 different MBTPS2 missense mutations detected in patients from 13 unrelated families were correlated with the clinical phenotype, with their effect on cellular growth in media without lipids, and their potential role for sterol control of transcription. Seven variants were novel [c.774C>G (p.I258M); c.758G>C (p.G253A); c.686T>C (p.F229S); c.1427T>C (p.L476S); c.1430A>T (p.D477V); c.1499G>A (p.G500D); c.1538T>C (p.L513P)], four had previously been reported in unrelated sibships [c.261G>A (p.M87I); c.1286G>A (p.R429H); c.1424T>C (p.F475S); c.1523A>G (p.N508S)]. In the enzyme, the mutations cluster in transmembrane domains. Amino-acid exchanges near the active site are more detrimental to functionality of the enzyme and, clinically, associated with more severe phenotypes. In male patients, a genotypephenotype correlation begins to emerge, linking the site of the mutation in MBTPS2 with the clinical outcome described as IFAP syndrome with or without BRESHECK syndrome, keratosis follicularis spinulosa decalvans, X-linked, Olmsted syndrome, or possibly further X-linked traits with an oculocutaneous component.
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| 11. |
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| 12. |
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| 13. |
- Busch, Christer, et al.
(författare)
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Expression of Cellular Retinoid-Binding Proteins During Normal and Abnormal Epidermal Differentiation
- 1992
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 99:6, s. 795-802
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Tidskriftsartikel (refereegranskat)abstract
- Retinoids have important roles in growth and differentiation of epidermal cells. We have analyzed the expression of two intracellular retinoid-binding proteins, the cellular retinol-binding protein type I and the cellular retinoic acid - binding protein type I, during normal and abnormal epidermal differentiation. Both proteins were found to be expressed in normal epidermis with increasing expression from basal layer towards superficial layers. In psoriatic lesions, a hyperproliferative condition of the skin, the epidermal expression of cellular retinol-binding protein I was induced, whereas expression of cellular retinoic acid-binding protein I was sharply down-regulated. This and other features of psoriatic lesions indicate that down-regulation of cellular retinoic acid - binding protein I expression might cause aberrant retinoid-regulated gene expression in skin. In basal and squamous cell carcinomas, cellular retinoic acid - binding protein I expression was down-regulated, whereas cellular retinol-binding protein I was expressed. Apart from epidermal cells, a mesenchymal, dendritic cell-type, strongly expressing cellular retinoic acid-binding protein I, was identified in the dermis. In several hyperproliferative conditions of the skin, including psoriasis, and squamous and basal cell carcinomas, this cell type was abundant. These results have implications for the role of retinoids in normal and abnormal epidermal differentiation and suggest that part of the phenotype of psoriasis is due to inappropriate metabolism of retinoic acid in skin.
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| 14. |
- Bygum, Anette, et al.
(författare)
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Generalized and Naevoid Epidermolytic Ichthyosis in Denmark: Clinical and Mutational Findings
- 2013
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 1651-2057 .- 0001-5555. ; 93:3, s. 309-313
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Tidskriftsartikel (refereegranskat)abstract
- A Danish Swedish collaboration was established to identify and classify a Danish cohort of patients with epidermolytic ichthyosis, also known as epidermolytic hyperkeratosis. Patients were recruited from 5 dermatology departments in Denmark, and data were obtained using a structured questionnaire and a systematic examination together with photographs, histopathological descriptions and blood samples for mutational analysis. Sixteen patients from 12 families with generalized or naevoid epidermolytic ichthyosis and ichthyosis bullosa of Siemens were identified. Five families had mutations in K1 and 6 families had mutations in K10. Nine patients had been treated with systemic retinoids (etretinate, acitretin, isotretinoin or alitretinoin), but only 3 patients had acceptable treatment responses and chose to continue therapy. In conclusion epidermolytic ichthyosis is a rare disease with a prevalence of approximately 1 in 350,000 in Denmark and a high percentage of de novo mutations (75%). We identified 4 novel disease-causing mutations.
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| 15. |
- Chamcheu, Jean Christopher, et al.
(författare)
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Characterization of immortalized human epidermolysis bullosa simplex (KRT5) cell lines : trimethylamine N-oxide protects the keratin cytoskeleton against disruptive stress condition
- 2009
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Ingår i: Journal of dermatological science (Amsterdam). - : Elsevier. - 0923-1811 .- 1873-569X. ; 53:3, s. 198-206
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Epidermolysis bullosa simplex (EBS) is an autosomal inherited mechano-bullous disease, characterized by intraepidermal blistering and skin fragility caused by mutations in the keratin (KRT) 5 or 14 genes. Despite a vast knowledge about the intermediate filament pathology in this disease, the progress in therapy has been slow. Animal models and well-characterized continuous cell culture models of EBS are needed prior to clinical testing. OBJECTIVES: Our aim was to generate immortalized cell lines as an in vitro model for the study of EBS and test a chemical chaperone, trimethylamine N-oxide (TMAO), as a putative novel therapy. METHODS: We generated four immortalized cell lines, two each from an EBS patient with a KRT5-mutation (V186L) and a healthy control, using human papillomavirus 16 (HPV16) E6E7 as transducer. Cell lines were established in serum-free and serum-containing medium and assessed for growth characteristics, keratin expression profiles, ability to differentiate in organotypic cultures, and response to heat stress with and without the presence of TMAO. RESULTS: All cell lines have been expanded >160 population doublings and their cellular characteristics are similar. However, the formation of cytoplasmic keratin filament aggregates in response to heat-shock treatment differed between EBS and normal cell lines. Notably, serum-free established EBS-cell line was most vulnerable to heat shock but both cell lines exhibited significant reduction in the number of keratin aggregates containing cells by TMAO. CONCLUSION: The immortalized cell lines represent a suitable model for studying novel therapies for EBS. TMAO is a promising new agent for future development as a novel EBS therapy.
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| 16. |
- Chamcheu, Jean Christopher, et al.
(författare)
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Chemical Chaperones Protect Epidermolysis Bullosa Simplex Keratinocytes from Heat Stress-Induced Keratin Aggregation : Involvement of Heat Shock Proteins and MAP Kinases
- 2011
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 131:8, s. 1684-1691
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Tidskriftsartikel (refereegranskat)abstract
- Epidermolysis bullosa simplex (EBS) is a blistering skin disease caused by mutations in keratin genes (KRT5 or KRT14), with no existing therapies. Aggregates of misfolded mutant keratins are seen in cultured keratinocytes from severe EBS patients. In other protein-folding disorders, involvement of molecular chaperones and the ubiquitin-proteasome system may modify disease severity. In this study, the effects of heat stress on keratin aggregation in immortalized cells from two patients with EBS (KRT5) and a healthy control were examined with and without addition of various test compounds. Heat-induced (43 °C, 30 minutes) aggregates were observed in all cell lines, the amount of which correlated with the donor phenotype. In EBS cells pre-exposed to proteasome inhibitor, MG132, and p38-mitogen-activated protein kinase (MAPK) inhibitor, SB203580, the proportion of aggregate-positive cells increased, suggesting a role of proteasomes and phosphorylation in removing mutated keratin. In contrast, aggregates were reduced by pretreatment with two chemical chaperones, trimethylamine N-oxide (TMAO) and 4-phenylbutyrate (4-PBA). TMAO also modulated stress-induced p38/c-jun N-terminal kinase (JNK) activation and expression of heat shock protein (HSPA1A), the latter of which colocalized with phosphorylated keratin 5 in EBS cells. Taken together, our findings suggest therapeutic targets for EBS and other keratinopathies.
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| 17. |
- Chamcheu, Jean Christopher, et al.
(författare)
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Chemical chaperones protect epidermolysis bullosa simplex keratinocytes from heat stress-induced keratin aggregation: : Involvement of heat shock proteins and MAP kinases
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Ingår i: Journal of Investigative Dermatology. - 0022-202X .- 1523-1747.
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Tidskriftsartikel (refereegranskat)abstract
- Epidermolysis bullosa simplex (EBS) is an inherited epithelial tissue fragility disorder due to mutations in keratin genes (KRT5 or KRT14), with no existing therapies. Aggregates of misfolded mutant keratins are seen in cultured keratinocytes from severe EBS patients. In some protein folding disorders such as cystic fibrosis and Alzheimer’s disease, chaperones and the ubiquitin-proteasome system modify disease severity, suggesting a novel therapeutic approach even for EBS. In this study, the effects of two chemical chaperones (trimethylamine-N oxide (TMAO) and 4-phenylbutyrate (4-PBA)) on heat stress-induced keratin aggregation responses were examined in newly and previously established immortalized control and EBS patient-derived keratinocyte cell lines. Heat-induced keratin-positive aggregates were observed in all EBS cells, which were most prominent in severe keratin-defective cell lines and less so in normal cells. The proportion of cells containing aggregates were dramatically reduced by TMAO and 4-PBA pretreatment. Furthermore, heat stress greatly induced MAP kinase activation (p38 and JNK) and increased Hsp70/Hsc70 expression, and TMAO was able to transiently modulate these effects. The results suggest that TMAO rescue may involve components of the endogenous chaperone and MAPK machineries, which may represent novel targets for the development of more effective treatments for EBS and other keratin-related genetic disorders.
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| 18. |
- Chamcheu, Jean Christopher
(författare)
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Disease-causing Keratin Mutations and Cytoskeletal Dysfunction in Human Skin : In vitro Models and new Pharmacologic Strategies for Treating Epidermolytic Genodermatoses
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Epidermolysis bullosa simplex (EBS) and epidermolytic ichthyosis (EI) are rare skin fragility diseases characterized by intra-epidermal blistering due to autosomal dominant-negative mutations in basal (KRT5 or KRT14) and suprabasal (KRT1 or KRT10) keratin genes, respectively. Despite vast knowledge in the disease pathogenesis, the pathomechanisms are not fully understood, and no effective remedies exist. The purpose of this work was to search for keratin gene mutations in EBS patients, to develop in vitro models for studying EBS and EI, and to investigate novel pharmacological approaches for both diseases. We identified both novel and recurrent KRT5 mutations in all studied EBS patients but one which did not show any pathogenic keratin mutations. Using cultured primary keratinocytes from EBS patients, we reproduced a correlation between clinical severity and cytoskeletal instability in vitro. Immortalized keratinocyte cell lines were established from three EBS and three EI patients with different phenotypes using HPV16-E6E7. Only cell lines derived from severely affected patients exhibited spontaneous keratin aggregates under normal culture conditions. However, heat stress significantly induced keratin aggregates in all patient cell lines. This effect was more dramatic in cells from patients with a severe phenotype. In organotypic cultures, the immortalized cells were able to differentiate and form a multilayered epidermis reminiscent of those observed in vivo. Addition of two molecular chaperones, trimethylamine N-oxide dihydrate (TMAO) and sodium 4-phenylbutyrate (4-PBA), reduced the keratin aggregates in both stressed and unstressed EBS and EI keratinocytes, respectively. The mechanism of action of TMAO and 4-PBA was shown to involve the endogenous chaperone system (Heat shock proteins e.g. Hsp70). Besides, MAPK signaling pathways also seemed to be incriminated in the pathogenesis of EBS. Furthermore, depending on which type of keratin is mutated, 4-PBA up-regulated Hsp70 and KRT4 (possibly compensating for mutated KRT1/5), and down-regulated KRT1 and KRT10, which could further assist in protecting EBS and EI cells against stress. In conclusion, novel and recurrent pathogenic keratin mutations have been identified in EBS. Immortalized EBS and EI cell lines that functionally reflect the disease phenotype were established. Two pharmacologic agents, TMAO and 4-PBA, were shown to be promising candidates as novel treatment of heritable keratinopathies in this in vitro model.
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| 19. |
- Chamcheu, Jean Christopher, et al.
(författare)
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Epidermolysis bullosa simplex due to KRT5 mutations : mutation-related differences in cellular fragility and the protective effects of trimethylamine N-oxide in cultured primary keratinocytes
- 2010
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Ingår i: British Journal of Dermatology. - : Wiley InterScience. - 0007-0963 .- 1365-2133. ; 162:5, s. 980-989
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Tidskriftsartikel (refereegranskat)abstract
- Summary Background Epidermolysis bullosa simplex (EBS) is a mechanobullous skin fragility disease characterized by cytolysis of basal keratinocytes and intraepidermal blistering often caused by mutations in keratin genes (KRT5 or KRT14). No remedies exist for these disorders presenting a need for development of novel therapies. Objectives To identify new genotype-phenotype relationships in vivo and in cultured primary EBS keratinocytes in vitro, and to study the cytoskeletal stabilizing effects of trimethylamine N-oxide (TMAO) in heat-stressed EBS cells. Methods Genomic DNA and cDNA samples from three Swedish patients with EBS were analysed for keratin mutations. Primary EBS keratinocyte cultures were established, heat stressed with and without added TMAO, followed by evaluation of cellular fragility. Results In addition to the previously reported KRT5 mutation (V186L) in one patient, two patients were found to have a novel I183M and recurrent E475G replacements in KRT5. Cultured EBS keratinocytes did not exhibit keratin aggregates or cell loss, except in the patient with the p.I183M mutation who showed 3% aggregates and 2% cell loss. Upon transient heat stress the number of aggregate-containing cells increased to 21%, 27% and 13%, respectively, in the p.I183M, p.E475G and p.V186L mutant cells. Interestingly, pretreatment with TMAO prior to heat stress, dose dependently reduced the number of aggregate-containing cells and cell loss. Conclusion These results revealed a genotype-phenotype correlation in EBS keratinocytes upon heat stress and suggest protein stabilization as a new therapeutic strategy.
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| 20. |
- Chamcheu, Jean Christopher, et al.
(författare)
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Immortalized keratinocytes derived from patients with epidermolytic ichthyosis reproduce the disease phenotype : A useful in vitro model for testing new treatments
- 2011
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Ingår i: British Journal of Dermatology. - : British Association of Dermatologists. - 0007-0963 .- 1365-2133. ; 164:2, s. 263-272
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Tidskriftsartikel (refereegranskat)abstract
- Background: Epidermolytic ichthyosis (EI) is a skin fragility disorder caused by mutations in genes encoding suprabasal keratins 1 and 10. While the aetiology of EI is known, model systems are needed for pathophysiological studies and development of novel therapies. Objectives To generate immortalized keratinocyte lines from patients with EI for studies of EI cell pathology and the effects of chemical chaperones as putative therapies. Methods We derived keratinocytes from three patients with EI and one healthy control and established immortalized keratinocytes using human papillomavirus 16-E6/E7. Growth and differentiation characteristics, ability to regenerate organotypic epidermis, keratin expression, formation of cytoskeletal aggregates, and responses to heat shock and chemical chaperones were assessed. Results The cell lines EH11 (K1-p.Val176-Lys197del), EH21 (K10-p.156Arg>Gly), EH31 (K10-p.Leu161-Asp162del) and NKc21 (wild-type) currently exceed 160 population doublings and differentiate when exposed to calcium. At resting state, keratin aggregates were detected in 9% of calcium-differentiated EH31 cells, but not in any other cell line. Heat stress further increased this proportion to 30% and also induced aggregates in 3% of EH11 cultures. Treatment with trimethylamine N-oxide and 4-phenylbutyrate (4-PBA) reduced the fraction of aggregate-containing cells and affected the mRNA expression of keratins 1 and 10 while 4-PBA also modified heat shock protein 70 (HSP70) expression. Furthermore, in situ proximity ligation assay suggested a colocalization between HSP70 and keratins 1 and 10. Reconstituted epidermis from EI cells cornified but EH21 and EH31 cells produced suprabasal cytolysis, closely resembling the in vivo phenotype. Conclusions These immortalized cell lines represent a useful model for studying EI biology and novel therapies.
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| 21. |
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| 22. |
- Dahlqvist, Johanna, 1979-, et al.
(författare)
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A single-nucleotide deletion in the POMP 5' UTR causes a transcriptional switch and altered epidermal proteasome distribution in KLICK genodermatosis
- 2010
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 86:4, s. 596-603
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Tidskriftsartikel (refereegranskat)abstract
- KLICK syndrome is a rare autosomal-recessive skin disorder characterized by palmoplantar keratoderma, linear hyperkeratotic papules, and ichthyosiform scaling. In order to establish the genetic cause of this disorder, we collected DNA samples from eight European probands. Using high-density genome-wide SNP analysis, we identified a 1.5 Mb homozygous candidate region on chromosome 13q. Sequence analysis of the ten annotated genes in the candidate region revealed homozygosity for a single-nucleotide deletion at position c.-95 in the proteasome maturation protein (POMP) gene, in all probands. The deletion is included in POMP transcript variants with long 5' untranslated regions (UTRs) and was associated with a marked increase of these transcript variants in keratinocytes from KLICK patients. POMP is a ubiquitously expressed protein and functions as a chaperone for proteasome maturation. Immunohistochemical analysis of skin biopsies from KLICK patients revealed an altered epidermal distribution of POMP, the proteasome subunit proteins alpha 7 and beta 5, and the ER stress marker CHOP. Our results suggest that KLICK syndrome is caused by a single-nucleotide deletion in the 5' UTR of POMP resulting in altered distribution of POMP in epidermis and a perturbed formation of the outermost layers of the skin. These findings imply that the proteasome has a prominent role in the terminal differentiation of human epidermis.
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| 23. |
- Dahlqvist, Johanna, et al.
(författare)
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Congenital ichthyosis : mutations in ichthyin are associated with specific structural abnormalities in the granular layer of epidermis
- 2007
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 44:10, s. 615-620
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Tidskriftsartikel (refereegranskat)abstract
- Background: Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of skin disorders. Several mutant genes have been identified in ARCI, but the association between genotype and phenotype is poorly understood. Methods: To investigate genotype–phenotype correlations in ARCI, we selected 27 patients from 18 families with specific ultrastructural features of the epidermis. The characteristic findings using electron microscopy (EM) were abnormal lamellar bodies and elongated membranes in the stratum granulosum, classified as ARCI EM type III. DNA samples from a subset of affected individuals were screened for homozygous genomic regions, and a candidate gene region was identified on chromosome 5q33. The region coincides with the ichthyin gene, previously reported as mutated in ARCI. Results: Mutation screening of ichthyin revealed missense or splice-site mutations in affected members from 16 of 18 (89%) families with characteristics of ARCI EM type III. In a control group of 18 patients with ARCI without EM findings consistent with type III, we identified one patient homozygous for a missense mutation in ichthyin. Discussion: Our findings indicate a strong association between ultrastructural abnormalities in the granular layer of epidermis and ichthyin mutations. The results also suggest that EM provides a tool for specific diagnosis in a genetically homogenous subgroup of patients with ARCI.
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| 24. |
- Dahlqvist, Johanna, 1979-
(författare)
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Genetic and Molecular Studies of Two Hereditary Skin Disorders
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Monogenic disorders, i.e., disorders caused by mutations in a single gene, are rare and clinically heterogeneous conditions. Identification of the genetic cause of monogenic traits can bring new insights into molecular pathways and disease mechanisms. The aims of the present study were to identify the mutant genes in two autosomal recessive skin disorders and to characterize the functions of the mutated genes. In order to identify candidate genes for the two disorders whole-genome SNP analysis, homozygosity mapping and gene sequencing were used. Autosomal recessive congenital ichthyosis (ARCI) is a group of disorders characterized by extensive scaling and redness of the skin. A subgroup of ARCI patients (n=27) was selected based on specific ultrastructural aberrations in their skin, revealed by electron microscopy. Mutations were identified in the Ichthyin gene in 93% of the selected patients, indicating a strong association between mutant Ichthyin and the specific morphological abnormalities. Ichthyin mRNA levels were shown to increase during keratinocyte differentiation in cells from healthy and affected individuals. Electron microscopy revealed a localization of ichthyin protein to keratins and desmosomes in epidermis. Staining of epidermal lipids identified aberrant lipid aggregates in skin sections of patients with Ichthyin mutations, indicating a role for Ichthyin in epidermal lipid metabolism. In twelve KLICK syndrome patients with ichthyosis, palmoplantar keratoderma and keratotic striae on joints, a single-nucleotide deletion was identified in the 5’ region of the proteasome maturation protein (POMP) gene. The deletion caused an increase in the proportion of POMP transcripts with long 5’ UTR’s in patient keratinocytes. Immunohistochemical analysis of differentiated skin cell layers revealed aberrant expression of POMP, proteasome subunits and the skin protein filaggrin in patients. CHOP expression, associated with endoplasmic reticulum stress, was increased in the same layers. siRNA silencing of POMP in cell cultures reduced proteasome subunit levels and induced expression of CHOP. The results indicate that the mutation in KLICK patients causes POMP and proteasome insufficiency with subsequent cellular stress. This study conclusively contributes to the understanding of epidermal physiology and the pathogenesis of two inherited skin diseases.
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| 25. |
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| 26. |
- Dahlqvist, Johanna, 1979-, et al.
(författare)
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Ichthyin/NIPAL4 localizes to keratins and desmosomes in epidermis and Ichthyin mutations affect epidermal lipid metabolism
- 2012
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Ingår i: Archives of Dermatological Research. - : Springer Science and Business Media LLC. - 0340-3696 .- 1432-069X. ; 304:5, s. 377-386
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Tidskriftsartikel (refereegranskat)abstract
- Autosomal recessive congenital ichthyosis (ARCI) is a group of disorders characterized by abnormal desquamation of the skin and a disrupted epidermal water barrier. Ichthyin/NIPAL4 gene mutations have been identified in a subgroup of ARCI patients, but the role of ichthyin in epidermis remains elusive. In order to obtain new insights concerning the characteristics of ichthyin and the ARCI pathogenesis, we studied the expression and localization of ichthyin and related epidermal components in cultured keratinocytes and skin sections from patients with Ichthyin mutations and healthy controls. We observed an up-regulation of Ichthyin mRNA levels after in vitro differentiation of keratinocytes from both a patient with Ichthyin mutations and controls. Confocal and electron microscopy analyses of immunolabeled skin sections revealed that ichthyin localizes to desmosomes and keratins in both patients with mutant Ichthyin and controls, with an increased immunolabeling in patients. Nile red lipid analysis of skin sections exposed intra-cellular lipid accumulations in cells of the granular and cornified layers in patients but not in controls, consistent with the pathognomonic lipid membrane structures previously identified in epidermis from patients. Our combined findings indicate that ichthyin is associated with keratins and desmosomes in epidermis and is involved in lipid metabolism, possibly through processing of lamellar bodies. These results provide new clues to the understanding of the epidermal water barrier and the pathogenesis in ARCI.
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| 27. |
- Danielsson, Carina, et al.
(författare)
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Positive and negative interaction of 1,25-dihydroxyvitamin D3 and the retinoid CD437 on the induction of apoptosis of human melanoma cells
- 1999
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Ingår i: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 81:3, s. 467-470
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Tidskriftsartikel (refereegranskat)abstract
- The natural ligands of the nuclear receptors vitamin D receptor (VDR) and retinoic acid receptor (RAR), i.e., 1alpha,25-dihydroxyvitamin D3 (VD) and all-trans retinoic acid, have important effects on the proliferation, differentiation and apoptosis of a variety of malignant cells, including melanoma. The therapeutic potential of the 2 nuclear hormones can be enhanced by the use of synthetic analogues. In this study, the 2 human melanoma cell lines WM1341 and MeWo were compared for the combined effect of VD and synthetic retinoids. Both cell lines expressed reasonable amounts of VDR, RARgamma and retinoid X receptor alpha and differed only in the relative expression of RARalpha and beta. From 9 functional variants of retinoids, only the RARgamma-selective retinoid CD437 showed, in both cell lines, a significant anti-proliferative effect. In MeWo cells, but not in WM1341 cells, VD induced growth arrest but showed no synergistic interaction with the effects of CD437. In contrast, VD induced apoptosis in WM1341, but not in MeWo, cells. CD437 was a strong inducer of apoptosis in both melanoma cell lines. Parallel treatment with CD437 and VD resulted in synergistic enhancement of apoptosis in WM1341 cells, whereas a clear decrease in induction of apoptosis in MeWo cells occurred. Our results indicate that a combined treatment of melanoma with VD and selected retinoids is promising but should be adapted to individual types of tumor.
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| 28. |
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| 29. |
- Fine, Jo-David, et al.
(författare)
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The classification of inherited epidermolysis bullosa (EB) : Report of the Third International Consensus Meeting on Diagnosis and Classification of EB
- 2008
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Ingår i: The Journal of American Academy of Dermatology. - : Elsevier BV. - 0190-9622 .- 1097-6787. ; 58:6, s. 931-950
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Since publication in 2000 of the Second International Consensus Report on Diagnosis and Classification of Epidermolysis Bullosa, many advances have been made to our understanding of this group of diseases, both clinically and molecularly. At the same time, new epidermolysis bullosa (EB) subtypes have been described and similarities with some other diseases have been identified. OBJECTIVE: We sought to arrive at a new consensus of the classification of EB subtypes. RESULTS: We now present a revised classification system that takes into account the new advances, as well as encompassing other inherited diseases that should also be included within the EB spectrum, based on the presence of blistering and mechanical fragility. Current recommendations are made on the use of specific diagnostic tests, with updates on the findings known to occur within each of the major EB subtypes. Electronic links are also provided to informational and laboratory resources of particular benefit to clinicians and their patients. LIMITATIONS: As more becomes known about this disease, future modifications may be needed. The classification system has been designed with sufficient flexibility for these modifications. CONCLUSION: This revised classification system should assist clinicians in accurately diagnosing and subclassifying patients with EB.
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| 30. |
- Forsberg, Sofi, 1980-
(författare)
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Human Epidermal Growth Factor Receptors and Biological Effects of HER-directed Molecules on Skin Epithelialization
- 2009
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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.
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| 31. |
- Gudmundsson, Sanna, et al.
(författare)
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Revertant mosaicism repairs skin lesions in a patient with keratitis-ichthyosis-deafness syndrome by second-site mutations in connexin 26
- 2017
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Ingår i: Human Molecular Genetics. - : OXFORD UNIV PRESS. - 0964-6906 .- 1460-2083. ; 26:6, s. 1070-1077
-
Tidskriftsartikel (refereegranskat)abstract
- Revertant mosaicism(RM) is a naturally occurring phenomenon where the pathogenic effect of a germline mutation is corrected by a second somatic event. Development of healthy-looking skin due to RM has been observed in patients with various inherited skin disorders, but not in connexin-related disease. We aimed to clarify the underlying molecular mechanisms of suspected RM in the skin of a patient with keratitis-ichthyosis-deafness (KID) syndrome. The patient was diagnosed with KID syndrome due to characteristic skin lesions, hearing deficiency and keratitis. Investigation of GJB2 encoding connexin (Cx) 26 revealed heterozygosity for the recurrent de novo germline mutation, c. 148G>A, p. Asp50Asn. At age 20, the patient developed spots of healthy-looking skin that grew in size and number within widespread erythrokeratodermic lesions. Ultradeep sequencing of two healthy-looking skin biopsies identified five somatic nonsynonymous mutations, independently present in cis with the p. Asp50Asn mutation. Functional studies of Cx26 in HeLa cells revealed co-expression of Cx26-Asp50Asn and wild-type Cx26 in gap junction channel plaques. However, Cx26-Asp50Asn with the second-site mutations identified in the patient displayed no formation of gap junction channel plaques. We argue that the second-site mutations independently inhibit Cx26-Asp50Asn expression in gap junction channels, reverting the dominant negative effect of the p. Asp50Asn mutation. To our knowledge, this is the first time RM has been reported to result in the development of healthy-looking skin in a patient with KID syndrome.
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| 32. |
- Gånemo, Agneta, et al.
(författare)
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Autosomal recessive congenital ichthyosis in Sweden and Estonia: clinical, genetic and ultrastructural findings in eithty-three patients
- 2003
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Ingår i: Acta Dermato-Venereologica. - 0001-5555 .- 1651-2057. ; 83:1, s. 24-30
-
Tidskriftsartikel (refereegranskat)abstract
- Congenital (non-bullous) ichthyosis is a rare group of keratinizing disorders which can be tentatively subclassified based on clinical criteria, analysis of transglutaminase 1 gene mutations and electron microscopy of epidermis. We studied 83 patients who were all on topical therapy and in 16 cases also on oral retinoids. Three main groups of patients were distinguished: (A) those with transglutaminase 1 gene mutations (n=44), (B) those without transglutaminase 1 gene mutations showing a coarse, generalized scaling (n=19), and (C) those without transglutaminase 1 gene mutations showing only fine or focal scaling (n=20). On clinical scoring, patients in group A were more hyperkeratotic and less erythematous than those in group B (p < 0.05). Anhidrosis was recorded in nearly all patients (> or = 80%), but ectropion and a collodion phenotype at birth were more common in group A versus other groups. Ultrastructurally, a high frequency of type I (Anton-Lamprecht's classification) was found in all three groups (37-63%), 20 cases of type II in group A and a few cases of types III and IV in groups B and C, respectively. In conclusion, transglutaminase 1 gene mutation is a major cause of congenital ichthyosis in Sweden and Estonia, and is often associated with severe scaling and ultrastructural type II in corneocytes. The transglutaminase-unrelated cases are more heterogeneous, probably reflecting a more varied aetiology.
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| 33. |
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| 34. |
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| 35. |
- Gånemo, Agneta, et al.
(författare)
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Sjögren-Larsson syndrome : a study of clinical symptoms and dermatological treatment in 34 Swedish patients
- 2009
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 89:1, s. 68-73
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Tidskriftsartikel (refereegranskat)abstract
- Sjögren-Larsson syndrome (SLS) is a recessively inherited disease with congenital ichthyosis, spastic diplegia or tetraplegia and mental retardation, caused by a deficiency of fatty aldehyde dehydrogenase. The aim of this study was to examine all 34 Swedish patients with SLS, emphasizing skin symptoms, dermatological treatment, and neurological symptoms (evaluated in some cases for more than 25 years by one and the same investigator). Structured interviews were conducted with the patients and their close relatives. All patients had generalized ichthyosis. The degree of scaling varied markedly inter-individually from moderate to severe, but there was no obvious change with age. Most patients had pruritus, suffered from hypohidrosis, and had palmo-plantar keratoderma. Nineteen patients (56%) were on oral acitretin and all patients were using some type of topical therapy. Motor disability with spasticity and muscular paresis was most pronounced in the legs and fairly slight in the arms. Twenty patients (59%) were dependent on a wheelchair for mobility. Poor blood circulation in the lower legs and oedematous feet were frequently found in adults. All patients had learning disability, which varied from slight to pronounced and was expressed in their speech disorders. Thirteen patients (38%) were being treated medically for epilepsy and all had photophobia. In conclusion, SLS is a chronic, severely disabling neurocutaneous disease in which optimal dermatological therapy is essential to relieve at least the patient's ichthyosis problem.
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| 36. |
- Hoppe, Torborg, et al.
(författare)
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Moisturizing treatment of patients with atopic dermatitis and ichthyosis vulgaris improves dry skin, but has a modest effect on gene expression regardless of FLG genotype
- 2015
-
Ingår i: Journal of the European Academy of Dermatology and Venereology. - : Wiley. - 0926-9959 .- 1468-3083. ; 29:1, s. 174-177
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundLoss-of-function mutations in FLG (encoding filaggrin) are a predisposing factor for atopic dermatitis (AD) and cause ichthyosis vulgaris (IV). Patients with AD and IV display impaired skin barrier and dry skin, and altered epidermal expression of genes in pro-inflammatory and lipid metabolic pathways are often evident.ObjectivesTo evaluate the effect of three different moisturizers on skin barrier function and epidermal gene expression in patients with AD/IV in relation to FLG mutation status.MethodsPatients (n = 43) were classified according to their FLG status: AD with FLG+/+ (n = 14), AD with FLG+/− (n = 14), and AD/IV with FLG−/− (n = 15). Dryness score and transepidermal water loss (TEWL) were monitored on volar forearms, and punch biopsies were taken for analysis of gene expression. Measurements were repeated after 4 weeks of treatment with either of two moisturizers on each forearm.ResultsTreatment with any of the three moisturizers significantly reduced dryness score and TEWL in the group as a whole. FLG−/− patients displayed the largest reduction in dryness score. Only minute changes occurred in the mRNA expression of 15 selected epidermal genes.ConclusionsMoisturizing treatment improves dry skin and certain aspects of abnormal skin barrier function, especially in patients with AD/IV and dual FLG mutations, but does not normalize the epidermal gene expression profile.
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| 37. |
- Hoppe, Torborg, et al.
(författare)
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X-linked recessive ichthyosis : an impaired barrier function evokes limited gene responses before and after moisturizing treatments
- 2012
-
Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 167:3, s. 514-522
-
Tidskriftsartikel (refereegranskat)abstract
- Background X-linked recessive ichthyosis (XLRI) is due to deletions or inactivating mutations in the steroid sulfatase (STS) gene. This results in an accumulation of cholesterol sulphate affecting the packing of intercorneocyte lipids. XLRI is characterized by dry, scaly skin and increased skin barrier permeability; patients are often dependent on daily use of moisturizers.Objectives To examine the biophysical and molecular changes in the skin of patients with XLRI compared with healthy volunteers, and to analyse the effects of moisturizers on the patients' barrier function.Methods Patients with XLRI (n = 14) and healthy controls (n = 14) were included in the study. Skin dryness score, transepidermal water loss (TEWL) and skin surface pH were monitored at baseline, and punch biopsies were obtained for mRNA expression profiles determined by oligonucleotide arrays. Measurements were repeated in the patients with XLRI after a 4-week treatment with three different moisturizers on the volar forearms. Results Patients with XLRI showed, compared with healthy controls, increased dryness and TEWL, equal skin pH and altered expression of 27 genes. There were no signs of activation of inflammation or repair pathways. Five selected genes were significantly altered also on quantitative polymerase chain reaction analysis. Treatment with the moisturizers showed similar effects: they improved skin dryness but had no effect on TEWL, pH or expression of selected genes.Conclusions Despite a dysfunctional skin barrier, the limited number of genes altered in XLRI skin suggests that no inflammatory or repair mechanisms are triggered. Treatment with moisturizers does not have any major impact on the skin barrier properties of patients with XLRI.
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| 38. |
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| 39. |
- Hotz, Alrun, et al.
(författare)
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Meta-Analysis of Mutations in ALOX12B or ALOXE3 Identified in a Large Cohort of 224 Patients
- 2021
-
Ingår i: Genes. - : MDPI. - 2073-4425. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- The autosomal recessive congenital ichthyoses (ARCI) are a nonsyndromic group of cornification disorders that includes lamellar ichthyosis, congenital ichthyosiform erythroderma, and harlequin ichthyosis. To date mutations in ten genes have been identified to cause ARCI: TGM1, ALOX12B, ALOXE3, NIPAL4, CYP4F22, ABCA12, PNPLA1, CERS3, SDR9C7, and SULT2B1. The main focus of this report is the mutational spectrum of the genes ALOX12B and ALOXE3, which encode the epidermal lipoxygenases arachidonate 12-lipoxygenase, i.e., 12R type (12R-LOX), and the epidermis-type lipoxygenase-3 (eLOX3), respectively. Deficiency of 12R-LOX and eLOX3 disrupts the epidermal barrier function and leads to an abnormal epidermal differentiation. The type and the position of the mutations may influence the ARCI phenotype; most patients present with a mild erythrodermic ichthyosis, and only few individuals show severe erythroderma. To date, 88 pathogenic mutations in ALOX12B and 27 pathogenic mutations in ALOXE3 have been reported in the literature. Here, we presented a large cohort of 224 genetically characterized ARCI patients who carried mutations in these genes. We added 74 novel mutations in ALOX12B and 25 novel mutations in ALOXE3. We investigated the spectrum of mutations in ALOX12B and ALOXE3 in our cohort and additionally in the published mutations, the distribution of these mutations within the gene and gene domains, and potential hotspots and recurrent mutations.
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| 40. |
- Karlsson, Teresa, et al.
(författare)
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13-cis-retinoic acid competitively inhibits 3 alpha-hydroxysteroid oxidation by retinol dehydrogenase RoDH-4 : a mechanism for its anti-androgenic effects in sebaceous glands?
- 2003
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - 0006-291X .- 1090-2104. ; 303:1, s. 273-278
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Tidskriftsartikel (refereegranskat)abstract
- Retinol dehydrogenase-4 (RoDH-4) converts retinol and 13-cis-retinol to corresponding aldehydes in human liver and skin in the presence of NAD(+). RoDH-4 also converts 3 alpha-androstanediol and androsterone into dihydrotestosterone and androstanedione, which may stimulate sebum secretion. This oxidative 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD) activity of RoDH-4 is competitively inhibited by retinol and 13-cis-retinol. Here, we further examine the substrate specificity of RoDH-4 and the inhibition of its 3 alpha-HSD activity by retinoids. Recombinant RoDH-4 oxidized 3,4-didehydroretinol-a major form of vitamin A in the skin-to its corresponding aldehyde. 13-cis-retinoic acid (isotretinoin), 3,4-didehydroretinoic acid, and 3,4-didehydroretinol, but not all-trans-retinoic acid or the synthetic retinoids acitretin and adapalene, were potent competitive inhibitors of the oxidative 3 alpha-HSD activity of RoDH-4, i.e., reduced the formation of dihydrotestosterone and androstandione in vitro. Extrapolated to the in vivo situation, this effect might explain the unique sebosuppressive effect of isotretinoin when treating acne.
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| 41. |
- Karlsson, Teresa, et al.
(författare)
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Immunofluorescence localization of nuclear retinoid receptors in psoriasis versus normal human skin
- 2004
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 84:5, s. 363-369
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Tidskriftsartikel (refereegranskat)abstract
- Psoriasis responds favourably to treatment with retinoids but the cellular pathways mediating these effects are poorly understood. Retinoids regulate keratinocyte proliferation and maturation via binding to nuclear retinoic acid receptors (mainly RARalpha and RARgamma) which form heterodimers with the 9-cis-RA receptor, RXRalpha. We have previously shown that mRNA expression of RARalpha and RXRalpha is down-regulated in psoriatic lesions as compared with non-lesional human skin. In the present study, we investigated the protein expression of RARalpha, RARgamma and RXRalpha in normal and psoriatic skin using indirect immunofluorescence analysis. Epidermal keratinocytes of normal and non-lesional psoriatic skin displayed similar nuclear localization of all three receptors; RARalpha was detected with decreasing intensity from basal to suprabasal layers, RARgamma showed the opposite trend, whereas RXRalpha was evenly expressed throughout the epidermis. In lesional psoriatic skin, however, all three receptor proteins showed a much higher staining intensity in the lower half of the epidermis; in particular, RARalpha immunoreactivity was low or even absent in the upper layers of epidermis. The results support the idea that psoriasis is associated with abnormal retinoid signalling in lesional epidermis.
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| 42. |
- Karlsson, Teresa, et al.
(författare)
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Keratinocyte differentiation induced by calcium, phorbol ester or interferon-γ elicits distinct changes in the retinoid signalling pathways
- 2010
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Ingår i: Journal of dermatological science (Amsterdam). - : Elsevier BV. - 0923-1811 .- 1873-569X. ; 57:3, s. 207-213
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Retinoids influence keratinocyte proliferation and differentiation via binding to nuclear retinoic acid receptors (RARα, -γ) and retinoid X receptor α (RXRα). The effect of keratinocyte differentiation on expression of nuclear retinoid receptors and on the conversion of retinol into retinoic acid has not been examined earlier in depth. Objectives: Our aim was to examine the expression of retinoid receptors and a retinoid-regulated gene CRABPII, as well as the metabolism of exogenous [3H]retinol in cultured human keratinocytes induced to differentiate by exposure to either calcium, phorbol 12-myristate 13-acetate (PMA), or interferon-γ (IFNγ). Methods: Normal human keratinocytes were cultured and exposed to differentiation-inducing agents. The mRNA and protein expression of retinoid receptors were examined using real-time PCR and Western blot. [3H]Retinol uptake and metabolism was monitored by HPLC with on-line radioactivity detection. Results: In calcium-exposed cells, increased expression of RARγ and RXRα, enhanced metabolism of [3H]retinol to 3,4-didehydro-RA (ddRA), and an induction of CRABPII mRNA and protein was noted. In contrast, treatment with PMA and IFNγ reduced the RARγ and RXRα protein expression (preventable by the proteasome inhibitor MG132), increased the accumulation of [3H]RA and/or [3H]ddRA in the cells, and changed the CRABPII transcription. Conclusions: Retinoid signalling is profoundly altered upon differentiation of keratinocytes and the effects depend on how cellular differentiation is initiated.
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| 43. |
- Karlsson, Teresa, et al.
(författare)
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Topical retinoic acid alters the expression of cellular retinoic acid-binding protein-I and cellular retinoic acid-binding protein-II in non-lesional but not lesional psoriatic skin
- 2002
-
Ingår i: Experimental dermatology. - : Wiley. - 0906-6705 .- 1600-0625. ; 11:2, s. 143-152
-
Tidskriftsartikel (refereegranskat)abstract
- Therapeutic retinoids have profound effects on psoriatic skin pathology but their interactions with various retinoid-binding proteins in lesional vs non-lesional skin have not been investigated. Using quantitative real-time PCR the mRNA expression of cellular retinol-binding protein I (CRBPI) and retinoic acid-binding protein I/II (CRABPI/CRABPII) was studied in psoriatic and healthy control (=normal) skin after 4 days of occlusive RA/vehicle treatment (n=6). Untreated psoriatic lesions showed a markedly elevated CRABPII/CRABPI ratio, while the CRBPI level was reduced in lesional and non-lesional skin as compared to normal skin. In RA-treated normal and non-lesional skin, the mRNA expression of CRBPI was unaltered while that of CRABPI and CRABPII was reduced by approximately 80% and increased approximately 5-fold, respectively, as compared to vehicle-treated skin. In contrast, lesional skin exposed to RA showed an almost 90% increase in CRBPI transcripts but unaltered expression of CRABPI and CRABPII, yet, the mRNA expression of several inflammatory mediators, e.g. inducible nitric oxide synthase, interferon-gamma and interleukin-1beta, was clearly reduced. Immunohistochemistry localized CRABPII to suprabasal keratinocytes in normal skin and revealed markedly elevated levels in lesional skin. RA treatment induced CRABPII protein expression in normal and non-lesional skin, to similar levels as in untreated lesions. The results indicate that the effects of RA differ in normal/non-lesional psoriatic skin and lesional skin. Whether the high expression of CRABPII in psoriatic skin lesions is due to increased amounts of endogenous retinoids in lesional skin or reflects an abnormal regulation of the CRABPII gene in psoriasis remains to be studied.
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| 44. |
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| 45. |
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| 46. |
- Klar, Joakim, 1974-, et al.
(författare)
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Mutations in the fatty acid transport protein 4 gene cause the ichthyosis prematurity syndrome
- 2009
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 85:2, s. 248-253
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Tidskriftsartikel (refereegranskat)abstract
- Ichthyosis prematurity syndrome (IPS) is an autosomal-recessive disorder characterized by premature birth and neonatal asphyxia, followed by a lifelong nonscaly ichthyosis with atopic manifestations. Here we show that the gene encoding the fatty acid transport protein 4 (FATP4) is mutated in individuals with IPS. Fibroblasts derived from a patient with IPS show reduced activity of very long-chain fatty acids (VLCFA)-CoA synthetase and a specific reduction in the incorporation of VLCFA into cellular lipids. The human phenotype is consistent with Fatp4 deficiency in mice that is characterized by a severe skin phenotype, a defective permeability barrier function, and perturbed VLCFA metabolism. Our results further emphasize the importance of fatty acid metabolism for normal epidermal barrier function illustrated by deficiency of a member in the FATP family of proteins.
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| 47. |
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| 48. |
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| 49. |
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| 50. |
- Li, Hao, 1984-
(författare)
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In vitro Studies of Genodermatoses Affecting Cytoskeletal Integrity and Lipid Processing in Human Epidermis : Pathogenic Mechanisms and Effects of Retinoid Therapy
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Autosomal dominant epidermolytic ichthyosis (EI) is a rare disease characterized by intra-epidermal blistering due to mutations in either of two keratin genes, KRT1 and KRT10, expressed by suprabasal keratinocytes. Autosomal recessive congenital ichthyosis (ARCI) is a non-blistering, hyperkeratotic disease caused by mutations in one of the following genes: ABCA12, ALOX12B, ALOXE3, TGM1, CYP4F22, NIPAL4 and SLC27A4, which are all essential for skin barrier homeostasis. ARCI and EI often respond well to treatment with retinoids, but the mechanism of action is unclear. The aim of this thesis was to increase the knowledge of pathogenic pathways in ichthyosis and to find new explanations to the effect of retinoids.In vitro studies of immortalized keratinocytes from EI patients showed an abnormal keratin aggregation after heat stress, that could be partially inhibited by pre-treatment with all-trans retinoic acid (ATRA) or retinoic acid receptor α-agonists. ATRA treatment also reduced the relative expression of mutated vs wildtype KRT10. The clearance of ATRA in human keratinocytes was found to be mediated by CYP26B1.In skin biopsies from ARCI patients, immunofluorescence analysis of 12R-LOX, eLOX-3, TGM1, ichthyin and FATP4 showed altered expression, not only of the mutated protein, but also of the other proteins. These observations are consistent with a feedback regulatory mechanism by which the loss of one protein results in an up-regulation of other proteins. Furthermore, 12R-LOX, eLOX-3 and TGM1 were intimately co-localized in stratum corneum, as were ichthyin and FATP4, suggesting that the proteins are linked to the same metabolic pathway. When treated with a CYP26 inhibitor known to raise the endogenous ATRA level of the skin, two patients with NIPAL4 mutations, initially exhibiting increased co-localization signals for 12R-LOX and eLOX-3, displayed normalized lipoxygenase expressions and showed clinical improvement.In conclusion, mechanisms are proposed by which pathogenic keratin aggregations in EI and epidermal protein deficiencies in ARCI patients may be mitigated by retinoids. Furthermore, the vivid crosstalk between proteins incriminated in ARCI suggests that these enzymes operate along a common metabolic pathway essential for producing barrier lipids in stratum corneum. Any abrogation of this production may cause barrier failure, hence resulting in a compensatory hyperkeratosis characteristic of congenital ichthyosis.
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