| 1. |
- Liu, Wei, et al.
(författare)
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Biosynthesis and function of all-trans- and 9-cis retinoic acid in parathyroid cells
- 1996
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 229:3, s. 922-929
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that cultured human and bovine parathyroid cells incubated with all-trans-[11,12-3H]-retinol convert this tracer into all-trans- and 9-cis-retinoic acid. By using RT-PCR, cellular retinol-binding protein type I (CRBP I), cellular retinoic acid binding protein I and II (CRABP I and II), retinoic acid receptors (RARs) alpha, beta and gamma, and 9-cis-retinoic acid receptor (RXR) alpha transcripts were detected in human parathyroid cDNA. CRBP I and CRABP I expression was confirmed by immunohistochemistry. Both 9-cis- and all-trans-RA were found to suppress parathyroid hormone (PTH) secretion from dispersed human adenomatous parathyroid cells, which was augmented by combined treatment with 1mM RA and 100 nM 1,25 (OH)2D3. The present data establish parathyroid gland as a target for retinoids and as a site of synthesis of the hormonal forms of vitamin A (retinol), all-trans- and 9-cis-retinoic acid.
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| 2. |
- 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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| 3. |
- 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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| 4. |
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| 5. |
- Botling, Johan, et al.
(författare)
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Vitamin D3 and retinoic acid induced monocytic differentiation : Interactions between the endogenous vitamin D3, retinoic acid and retinoid X receptors in U-937 cells
- 1996
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Ingår i: Cell growth & differentiation. - 1044-9523. ; 7:9, s. 1239-49
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Tidskriftsartikel (refereegranskat)abstract
- Retinoic acid (RA) and 1,25 alpha-dihydroxycholecalciferol (VitD3) are potent regulators of hematopoletic differentiation. Yet, little is known as to how the RA and VitD3 receptor network operates in hematopoietic cells, and whether receptor interactions can explain the interplay between the RA- and VitD3-signaling pathways during differentiation. Therefore, we analyzed the expression, DNA binding, and transcriptional activity of the endogenous RA and VitD3 receptors [retinoic acid receptors (RARs), retinoid X receptors (RXRs), and VitD3 receptor (VDR)] in the U-937 cell line, in which RA and VitD3 induce distinct monocytic differentiation pathways. VitD3 induction resulted in the formation of VDR/RXR DNA-binding complexes on both VitD3 response elements and RA response elements (RAREs). However, transcriptional activation was only observed from a VitD3 response element-driven reporter construct. Several DNA-binding complexes were detected on RAREs in undifferentiated cells. Stimulation by RA resulted in increased RAR beta/RXR DNA binding, activated RARE-dependent transcription, and increased expression of RAR-beta. Concomitant stimulation by VitD3 inhibited the RA-stimulated formation of RAR beta/RXR heterodimers, favoring VDR/RXR binding to the RARE. Also, VitD3 inhibited the expression of CD23 and CD49f, characteristic markers of retinoid-induced U-937 cell differentiation. In contrast, neither the RA-stimulated, RARE-mediated transcription nor the induced RAR-beta expression was suppressed by VitD3, suggesting that VitD3 selectively inhibited the retinoid-induced differentiation program but not the RARE-mediated signal. These results demonstrate a complex role for VitD3 in modifying the retinoid differentiation pathway and may have implications for differentiation-inducing therapy of hematopoietic tumors.
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| 6. |
- Buraczewska, Izabela, et al.
(författare)
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Changes in skin barrier function following long-term treatment with moisturizers, a randomized controlled trial
- 2007
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 156:3, s. 492-498
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Moisturizers are commonly used by patients with dry skin conditions as well as people with healthy skin. Previous studies on short-term treatment have shown that moisturizers can weaken or strengthen skin barrier function and also influence skin barrier recovery. However, knowledge of the effects on skin barrier function of long-term treatment with moisturizers is still scarce. OBJECTIVES: To investigate the impact of long-term treatment with moisturizers on the barrier function of normal skin, as measured by transepidermal water loss (TEWL) and susceptibility to an irritant, and to relate those effects to the composition of the designed experimental moisturizers. METHODS: Volunteers (n = 78) were randomized into five groups. Each group treated one volar forearm for 7 weeks with one of the following preparations: (i) one of three simplified creams, containing only a few ingredients in order to minimize the complexity of the system; (ii) a lipid-free gel; (iii) one ordinary cream, containing 5% urea, which has previously been shown to decrease TEWL. The lipids in the simplified creams were either hydrocarbons or vegetable triglyceride oil, and one of them also contained 5% urea. After 7 weeks, treated and control forearms were exposed for 24 h to sodium lauryl sulfate (SLS) using a patch test. TEWL, blood flow and skin capacitance of both SLS-exposed and undamaged skin were evaluated 24 h after removal of patches. Additionally, a 24-h irritancy patch test of all test preparations was performed on 11 volunteers in order to check their possible acute irritancy potential. RESULTS: Changes were found in the barrier function of normal skin after 7 weeks of treatment with the test preparations. The simplified creams and the lipid-free gel increased TEWL and skin response to SLS, while the ordinary cream had the opposite effect. One of the simplified creams also decreased skin capacitance. All test preparations were shown to be nonirritant, both by short-term irritancy patch test and by measurement of blood flow after long-term treatment. CONCLUSIONS: Moisturizers influence the skin barrier function of normal skin, as measured by TEWL and susceptibility to SLS. Moreover, the effect on skin barrier function is determined by the composition of the moisturizer. The ingredients which influence the skin barrier function need to be identified, and the mechanism clarified at the molecular level.
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| 7. |
- Buraczewska, Izabela, et al.
(författare)
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Long-term treatment with moisturizers affects the mRNA levels of genes involved in keratinocyte differentiation and desquamation
- 2009
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Ingår i: Archives of Dermatological Research. - : Springer Science and Business Media LLC. - 0340-3696 .- 1432-069X. ; 301:2, s. 175-181
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Tidskriftsartikel (refereegranskat)abstract
- In a recent study, we showed that long-term treatment with two different moisturizers affected TEWL in opposite directions. Therefore, we decided to examine the effect of these moisturizers on the cellular and molecular level. In a randomized controlled study on 20 volunteers, epidermal mRNA expression of genes essential for keratinocyte differentiation and desquamation after a 7-week treatment with two moisturizers was analyzed. Treatment with one test moisturizer increased gene expression of involucrin, transglutaminase 1, kallikrein 5, and kallikrein 7, while the other moisturizer affected only expression of cyclin-dependent kinase inhibitor 1A. Thus, moisturizers are able to modify the skin barrier function and change the mRNA expression of certain epidermal genes. Since the type of influence depends on the composition of the moisturizer, these should be tailored in accordance with the requirement of the barrier of each individual patient, which merits further investigations.
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| 8. |
- Buraczewska, Izabela, et al.
(författare)
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Moisturizers change the mRNA expression of enzymes synthesizing skin barrier lipids
- 2009
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Ingår i: Archives of Dermatological Research. - : Springer Science and Business Media LLC. - 0340-3696 .- 1432-069X. ; 301:8, s. 587-594
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, 7-week treatment of normal human skin with two test moisturizers, Complex cream and Hydrocarbon cream, was shown to affect mRNA expression of certain genes involved in keratinocyte differentiation. Moreover, the treatment altered transepidermal water loss (TEWL) in opposite directions. In the present study, the mRNA expression of genes important for formation of barrier lipids, i.e., cholesterol, free fatty acids and ceramides, was examined. Treatment with Hydrocarbon cream, which increased TEWL, also elevated the gene expression of GBA, SPTLC2, SMPD1, ALOX12B, ALOXE3, and HMGCS1. In addition, the expression of PPARG was decreased. On the other hand, Complex cream, which decreased TEWL, induced only the expression of PPARG, although not confirmed at the protein level. Furthermore, in the untreated skin, a correlation between the mRNA expression of PPARG and ACACB, and TEWL was found, suggesting that these genes are important for the skin barrier homeostasis. The observed changes further demonstrate that long-term treatment with certain moisturizers may induce dysfunctional skin barrier, and as a consequence several signaling pathways are altered.
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| 9. |
- Buraczewska, Izabela, 1976-
(författare)
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Skin barrier responses to moisturizers
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Moisturizers are used in various types of dry skin disorders, but also by people with healthy skin. It is not unusual that use of moisturizers is continued for weeks, months, or even years. A number of moisturizers have been shown to improve the skin barrier function, while others to deteriorate it, but the reason for observed effects remains unknown. Further understanding of the mechanism by which long-term treatment with moisturizers influences the skin barrier would have clinical implications, as barrier-deteriorating creams may enhance penetration of allergens or irritants and predispose to dry skin and eczema, while barrier-improving ones could reduce many problems. The present research combined non-invasive techniques with analyses of skin biopsies, allowing studies of the epidermis at molecular and cellular level. Test moisturizers were examined on healthy human volunteers for their effect on the skin barrier, with regard to such factors as pH, lipid type, and presence of a humectant, as well as complexity of the product. After a 7-week treatment with the moisturizers, changes in transepidermal water loss, skin capacitance, and susceptibility to an irritant indicated a modified skin barrier function. Moreover, the mRNA expression of several genes involved in the assembly, differentiation and desquamation of the stratum corneum, as well as lipid metabolism, was altered in the skin treated with one of the moisturizers, while the other moisturizer induced fewer changes. In conclusion, long-term use of moisturizers may strengthen the barrier function of the skin, but also deteriorate it and induce skin dryness. Moisturizers have also a significant impact on the skin biochemistry, detectable at molecular level. Since the type of influence is determined by the composition of a moisturizer, more careful selection of ingredients could help to design moisturizers generating a desired clinical effect, and to avoid ingredients with a negative impact on the skin.
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| 10. |
- 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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