Immunofluorescence localization of nuclear retinoid receptors in psoriasis versus normal human skin

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.     

Study on the expression of RXRalpha in patients with psoriasis vulgaris

Retinoic acid regulates keratinocyte proliferation and differentiation--processes that are disturbed in psoriatic skin--via binding to nuclear receptors, including retinoic acid receptor (RAR-alpha,beta,gamma) and the common heterodimer partners (RXR-alpha,beta,gamma). By RT-PCR and immunohistochemistry methods, the expression of RXRalpha was studied in psoriatic skin and controls. The expression of RXRalpha was down-regulated in patients with psoriasis; moreover, its level was related to the stage of the disease; in the progressive stage of the disease, the level of the RXRalpha was lower than in the stable stage. The results suggest that retinoid signaling is abnormal in lesional psoriatic skin, RXRalpha expression is mainly confined to differentiated keratinocytes.     

Increased expression of adhesion receptors in both lesional and non-lesional psoriatic skin

Adhesion receptors and their ligands play a vital role in the immune system. We studied the expression of different adhesion receptors, using single- and double-staining immunohistochemical techniques, in both lesional and non-lesional skin specimens from seven psoriasis patients and in skin biopsy specimens from eight normal healthy controls. Our results showed an overall increased expression of several adhesion receptors in both lesional and non-lesional psoriatic skin. We consistently found an increased expression in particular of ICAM-1 and E-selectin on endothelial cells, and ICAM-1 on T cells and Langerhans cells. In contrast, a weak expression of VCAM-1 was found on endothelial cells and mononuclear cells in lesional psoriatic skin specimens alone. Interestingly, LFA-1 was also expressed on Langerhans cells, with a greater frequency in skin from lesional than from non-lesional sites, but was never expressed in skin from normal healthy individuals. Furthermore, significantly increased numbers of Langerhans cells and T cells with a positive reactivity for MAb HECA-452 were found in both lesional and non-lesional psoriatic skin. We hypothesize that the enhanced expression of adhesion receptors on migrating immunocompetent cells and endothelial cells of psoriatic skin in general facilitates the increased influx of activated T lymphocytes and other immunocomponent cells into the skin, and thus underscores the generalized character of the disease.     

Alterations of glucosylceramide-beta-glucosidase levels in the skin of patients with psoriasis vulgaris

Hydrolysis of glucosylceramides by the enzyme glucosylceramide-beta-glucosidase (GlcCer'ase) results in ceramide, a critical component of the intercellular lamellae that mediates the epidermal permeability barrier. A disturbance of ceramide formation is supposed to influence the transepidermal water loss in common skin diseases like atopic eczema or psoriasis. The aim of this study was to investigate whether GlcCer'ase levels were altered in the skin of subjects with psoriasis vulgaris. Skin punch biopsies were taken from lesional and non-lesional psoriatic skin and GlcCer'ase was evaluated both at the RNA and at the protein level. Normal skin from surgical patients provided the baseline GlcCer'ase expression in healthy subjects. Our results show that GlcCer'ase mRNA expression was decreased in psoriatic non-lesional skin compared to normal controls in all cases. Interestingly, in lesional psoriatic skin the level of GlcCer'ase was increased compared to non-lesional skin in all cases. For the immunohistochemical analysis, we used a newly synthesized monoclonal antibody anti-human GBC (GlcCer'ase-GST fusion protein). The results confirmed that GlcCer'ase, mainly present in the upper epidermis, was decreased in psoriatic skin compared to normal control and was increased in lesional compared to non-lesional psoriatic skin. Our findings support the concept that alteration in water permeability barrier in lesional psoriatic skin can serve as a trigger for the upregulation of the expression of enzymes like GlcCer'ase with consequent stimulation of ceramide generation.     

早幼粒细胞白血病基因及其蛋白在银屑病表皮中的表达

目的探讨早幼粒细胞白血病(PML)基因及其蛋白在银屑病发病中的作用机制。方法用原位杂交和免疫组化方法检测正常组织、进行期银屑病皮损及非皮损区PMLmRNA和蛋白表达。结果在正常人皮肤组织中,PMLmRNA和蛋白不表达(阴性);在非皮损区,PMLmRNA和蛋白在基底层和基底上层细胞核内低表达(52%,36%);在银屑病皮损周边PMLmRNA和蛋白在基底层和基底上层细胞核内呈灶状表达(72%,64%);在银屑病皮损中心表皮中,PMLmRNA和蛋白高表达(96%,88%)。结论PML基因和其蛋白在银屑病表皮中的过表达提示,PML基因可能与银屑病表皮细胞的过度增殖相关。     

银屑病皮损VDR表达水平的研究

为了解维生素D受体（VDR）在银屑病皮损中的表达情况,采用RT－PCR方法检测了10例寻求型银屑病患者皮损VDR mRNA表达水平,并与正常人皮肤做对照。结果显示：寻常型银屑病患者皮损VDR mRNA水平明显低于 正常人皮肤（P＜0．05）,寻常型银屑病皮损VDR mRNA水平下降,可能与银屑病的发病有一定的关系。     

银屑病患者皮损中转化生长因子-β1及受体基因表达的研究

目的 研究银屑病患者皮损及非皮损处转化生长因子-β1(TGF-β1)、转化生长因子β受体(TGF-βRⅡ)及CD105的基因(mRNA)表达,并初步探讨其临床意义。方法 采用异硫氰酸胍法抽提皮肤组织中的RNA;采用逆转录聚合酶链反应(RT-PCR)检测皮肤组织中mRNA的表达。结果 银屑病患者皮损组织TGF-β1及TGF-βRⅡmRNA的表达均低于非皮损组织及正常人(P<0.05);非皮损组织及正常人皮肤组织中mRNA的表达量差异无显著性(P>0.05)。而银屑病皮损组织CD105的mRNA表达量高于非皮损组及正常人(P<0.05);非皮损组织和正常人皮肤组织比较P>0.05。结论 银屑病皮损中TGF-β1及TGF-βRⅡ表达降低和CD105的表达上调可能与银屑病的表皮过度增殖及真皮炎症细胞浸润有关。     

Interferon alpha-inducible protein 27 (IFI27) is upregulated in psoriatic skin and certain epithelial cancers

IFI27 is an interferon alpha-inducible protein found to be upregulated in lesional and non-lesional psoriatic skin in a gene array study. To further characterize its function, we studied by in situ hybridization whether IFI27 is expressed in psoriasis, other inflammatory skin diseases, and wound repair in vivo. We also examined its regulation by different growth factors and anti-psoriatic agents using quantitative RT-PCR (TaqMan). IFI27 mRNA expression was highly upregulated in lesional psoriatic epidermis and also detected in non-lesional keratinocytes. It was also expressed in lichen planus, chronic eczema, cutaneous squamous cell cancers, and during normal wound repair when IFI27 was found in the proliferating subpopulation of keratinocytes. A 3-17-fold upregulation of IFI27 mRNA expression was observed when keratinocytes were stimulated with IFN-gamma, TNF-alpha, or TGF-beta1 while retinoids and vitamin D downregulated its expression. Our results suggest that IFI27 is a novel marker of epithelial proliferation and cancer.     

The Increased Expression of Matrix Metalloproteinase-9 Messenger RNA in the Non-lesional Skin of Patients with Large Plaque Psoriasis Vulgaris

Background

A difference of the interleukin-18 (IL-18) mRNA expression among several proinflammatory genes was previously observed between large plaque (LP) psoriasis patients (more than 5 cm lesions are typical) and small plaque (SP) psoriasis patients (1~2 cm lesions are typical). Therefore, it is necessary to test whether there is any difference in the expression of the genes that activate IL-18 or the expression of genes that are induced by IL-18.

Objective

To test the differential mRNA expressions of caspase-1, STAT-6, MMP-1, MMP-2, MMP-9 and TIMP-1 according to the clinical types of psoriasis vulgaris lesions in Korean patients, we have analyzed the skin samples of psoriasis vulgaris patients.

Methods

The total cellular RNA of skin samples from groups of patient with LP and SP psoriasis was analyzed by performing real-time PCR (the Taqman method) to compare the differences in the mRNA expressions.

Results

The caspase-1 and STAT-6 mRNA expression levels from the SP lesional skin of the patients were increased compared with the caspase-1 and STAT-6 mRNA expression levels from SP non-lesional skin or normal skin, but these expression levels from the SP non-lesional skin were not significantly different from those of the LP non-lesional skin. Among MMP-1, MMP-2, MMP-9 and TIMP-1, the expressions of MMP-1, MMP-2 and MMP-9 mRNA were increased in the SP lesional skin compared with those of the SP non-lesional skin. The MMP-1 mRNA expressions in both the LP and SP lesional skin were increased compared with those in the normal skin (p=0.028 and p=0.007 respectively). The MMP-9 mRNA expression in the LP non-lesional skin was elevated compared with the MMP-9 mRNA expression in the SP non-lesional skin (p=0.047). The TIMP-1 mRNA expression levels from the non-lesional skin and the lesional skin of the psoriasis patients and the normal skin samples were not significantly different.

Conclusion

The increased expression of MMP-9 mRNA in the LP non-lesional skin compared to that of the SP non-lesional skin in the psoriatic skin suggests that the increased MMP-9 mRNA expression is related to the large size type of lesion.     

Gene expression analysis of melanocortin system in vitiligo

BACKGROUND: The melanocortin system in the skin coordinates pigmentation and immune response and could be implicated in the pathogenesis of vitiligo. OBJECTIVES: We aimed to analyze changes in expression of genes involved in skin pigmentation (melanocortin system and enzymes involved in melanin synthesis). METHODS: With quantitative RT-PCR we measured the mRNA expression levels of eight genes from the melanocortin system and two enzymes involved in melanogenesis. RNA was extracted from both lesional and non-lesional skin of vitiligo patients and in non-sun-exposed skin of healthy subjects. RESULTS: POMC (proopiomelanocortin) expression was lower in lesional skin compared to non-lesional skin. Expression of melanocortin receptors was increased in unaffected skin of vitiligo patients compared to healthy subjects and decreased in lesional skin compared to uninvolved skin of vitiligo patients, the differences were statistically significant in the cases of MC1R (melanocortin receptor 1) and MC4R (melanocortin receptor 4). TRP1 and DCT genes were down-regulated in lesional skin compared to non-lesional vitiligo skin or skin of healthy controls and up-regulated in uninvolved vitiligo skin compared to healthy control samples. In non-lesional skin, POMC expression was not elevated, possibly indicating that systemic influences are involved in up-regulation of MC receptor genes. Decreased expression of the analyzed genes in the lesional skin is not surprising, but statistically significant increased expression of studied genes in non-lesional skin from vitiligo patients is not described previously. CONCLUSION: In our mind, up-regulation of melanocortin system in non-lesional skin could be systemic compensation to restore normal pigmentation in lesions.     

寻常性银屑病皮损及非皮损中IL-23(p19/p40)和IL-12(p35/p40)mRNA的表达

目的检测寻常性银屑病患者皮损及非皮损处IL-23(p19/p40)和IL-12(p35/p40)mRNA表达,探讨其临床意义。方法采用逆转录-聚合酶链反应(RT-PCR)检测寻常性银屑病患者皮损、非皮损处及正常人皮肤中IL-23(p19/p40)和IL-12(p35/p40)mRNA的表达水平。结果寻常性银屑病患者皮损中IL-23p19及p40(IL-23/IL-12)mRNA的表达均高于非皮损组织和正常皮肤组织(P<0.05),且非皮损处高于正常对照组,差异有显著性(P<0.05);IL-12p35mRNA在银屑病皮损处、非皮损处和正常对照中表达水平差异无显著性(P>0.05)。结论在寻常性银屑病发病过程中,IL-23可能发挥较IL-12更重要的作用。     

银屑病表皮热休克蛋白27、70、60的表达

目的：探讨热休克蛋白（HSP）在银屑病发病中的作用。方法：通过免疫组化和图像分析检测了25例银屑病患者治疗前后皮损、非皮损区表皮组织中HSP27、HSP70和HSP60的表达，并与6例正常人作对照。结果：HSP27、HSP70在非皮损、正常人表皮中呈基础表达，在银屑病患者皮损中的表达很弱，治愈后表皮后HSP27、HSP70的表达又恢复；HSP60的表达在银屑病皮损组表皮中均为阳性，而银屑病非皮损组、治愈后组表皮中及正常人对照表皮组织中HSP60的表达均阴性。结论：热休克蛋白在银屑病应激保护机制中可能发挥一定的作用。     

Immunoreactivity to CYP24A1, but not vitamin D receptor,is increased in mast cells of keratinocyte skin cancers

Background

In mouse skin models, mast cells have been shown to express vitamin D receptor (VDR) that can mediate the immunosuppressive effects of ultravioletBradiation and vitamin D₃. However,VDR activation leads to the expression of CYP24A1, a hydroxylase that can inactivate vitamin D₃ metabolites.

Objectives

To examine immunoreactivity to VDR and CYP24A1 in mast cells from normal human skin, keratinocyte skin cancers, and disorders of chronic inflammation.

Materials & methods

Frozen biopsies were collected from the non-lesional and lesional skin of patients with actinic keratosis (AK), Bowen’s disease/ squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and psoriasis. The expression of VDR and CYP24A1 in tryptase-positive mast cells was analysed using double-staining methods.

Results

Less than 0.5% of the mast cells were immunoreactive to VDR in both the non-lesional and lesional skin for all disease groups. In non-lesional skin, only 0.5-2.9% of the mast cells were immunopositive for CYP24A1, however, the percentage of mast cells containing CYP24A1 was significantly increased in lesional skin of AK, SCC, and BCC. In contrast to human skin, LAD2 mast cells cultured from a patient with mast cell sarcoma/leukaemia revealed that about 34% and 6.5% of the cells were immunopositive forVDRand CYP24A1, respectively.

Conclusion

Whereas a very small proportion of mast cells in human skin express VDR and CYP24A1, the proportion of mast cells expressing CYP24A1 in keratinocyte skin cancers is increased; the mechanism underlying this is unclear.

     

过氧化物酶增殖物激活受体β/δ在银屑病角质形成细胞中的表达

【摘要】 目的 探讨过氧化物酶增殖物激活受体β/δ（PPARβ/δ）在银屑病患者表皮角质形成细胞（KC）中的表达和调节因素。 方法 免疫组化方法检测PPARβ/δ在银屑病患者皮损及非皮损表皮中的表达。分离、培养银屑病患者非皮损区和皮损区的KC,以RT-PCR和Western印迹法分别检测银屑病患者皮损区和非皮损区KC中PPARβ/δ mRNA和蛋白质的表达水平。利用PPARβ/δ外源性激动剂GW501516及Ca2+刺激银屑病非皮损区KC,观察其对PPARβ/δ表达的调节影响。 结果 免疫组化显示,银屑病皮损区PPARβ/δ的表达强度显著高于正常对照组（t = 19.28,P < 0.01）和非皮损区（t = 23.26,P < 0.01）。银屑病皮损区PPARβ/δ mRNA和蛋白质的表达水平均高于正常对照组（P < 0.01）和非皮损区（P < 0.01）。10 ng/ml GW501516最大效能促进PPARβ/δ的表达（P < 0.01）;1.0 mmol/L Ca2+对KC中PPARβ/δ的表达促进效应最明显（P < 0.01）。 结论 PPARβ/δ在银屑病患者皮损区表达显著升高,GW501516 和Ca2+能够促进角质形成细胞PPARβ/δ表达水平。     

肝素结合表皮生长因子样生长因子在银屑病早期皮损中的意义

目的：探讨肝素结合表皮生长因子样生长因子（HB－EGF）在银屑病发上期中的作用机制。方法：用原位杂交和免疫组化的方法检测正常组织、进行期银屑病皮损及其未受累皮肤中HB－EGF mRNA的蛋白表达。结果：在正常人皮肤组织中，HB－EGF mRNA和蛋白位于基底层（100％），基底上层仅有少量表达（16．67％）；在未受累表皮和银屑病皮损的周围部分中，HB－EGF的表达不仅位于基底层，且以灶状高表达于基底上层（分别为88．00％、80．00％）；在银屑病皮损的中央部分，基底上层无HB－EGF表达，基底层几乎不表达（4．00％）。结论：HB－EGF可能在银屑病发病的早期阶段起重要作用。     

干细胞因子及其受体在寻常型白癜风表皮中的表达

目的 探讨SCF/c-kit信号通路在白癜风发病中的作用。方法 采用免疫组化和RT-PCR法检测17例寻常型稳定期白癜风患者和10例正常对照标本中表皮角质形成细胞的干细胞因子表达及基底层黑素细胞c-kit的表达情况。结果 白癜风非皮损区干细胞因子、c-kit蛋白表达与正常对照无明显差异(P>0.05),皮损区干细胞因子表达显著高于正常对照皮肤(P<0.05),而c-kit表达显著低于正常对照皮肤(P<0.05)。白癜风非皮损区表皮干细胞因子、c-kit mRNA表达平均水平与正常对照近似(P>0.05);皮损区干细胞因子mRNA表达水平高于非皮损区及正常对照组差异有统计学意义(P<0.05);皮损区c-kit mRNA表达水平显著低于非皮损区及正常对照组(P<0.05)。结论 SCF/c-kit的异常表达可能与白癜风的发病有关。     

银屑病皮损及非皮损中垂体腺苷酸环化酶激活肽及其受体的研究

目的 探讨垂体腺苷酸环化酶激活肽(PACAP)及其受体(PACAP-R)在银屑病发病中的意义。方法 采用免疫组化的方法研究寻常性银屑病患者皮损及非皮损部位PACAP及PACAP-R的原位表达情况。结果 银屑病患者皮损部位PACAP及PACAP-R的原位表达均明显低于非皮损部位,表现为皮损组PACAP及PACAP-R的面积密度及平均吸光度值显著低于正常人对照组(均为P<0.01);与正常人相比,非皮损部位PACAP及PACAP-R的原位表达也呈下调表达,即非皮损组的PACAP及PACAP-R的面积密度及平均吸光度值明显低于正常人对照组(P<0.05)。结论 PACAP及PACAP-R在银屑病皮损中下调表达,提示PACAP可能与银屑病表皮细胞的过度增殖有关。     

Dermal fibroblasts are one of the therapeutic targets for topical application of 1alpha,25-dihydroxyvitamin D3: the possible involvement of transforming growth factor-beta induction

BACKGROUND: Transforming growth factor (TGF) -beta has been suggested to be an effective inhibitor for abnormal keratinocyte growth in psoriasis. As a majority of the secreted TGF-beta are biologically latent complexes, activation is essential for TGF-beta-mediated cellular responses in vitro and in vivo. Objectives Here we report the response of the TGF-beta regulation system to 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3], an active vitamin D3 analogue Patients/methods We studied two types of fibroblasts derived from normal and psoriatic lesional skin, using an enzyme-linked immunosorbent assay and Northern blotting techniques. RESULTS: 1,25(OH)2D3 caused a dose-dependent induction of latent and active TGF-beta1 proteins in both cell cultures. The increases were significant over 72 h, but not within 48 h after stimulation. The time course of TGF-beta1 mRNA expression showed a biphasic response consisting of early ( approximately 1 h) and late phases ( approximately 96 h) of induction. Concomitant increases of TGF-beta2 and -beta3, other mammalian isoforms, were observed in the 1,25(OH)2D3-treated cells, but the kinetics were all different. Co-incubation with metabolic inhibitors, actinomycin D and cycloheximide, revealed that the early induction of TGF-beta1 mRNA by 1,25(OH)2D3 is dependent on de novo RNA synthesis, but not on RNA stabilization or protein synthesis. It seems likely to be a transient and negligible response given the absence of TGF-beta1 protein production. The late induction of TGF-beta1 mRNA was partially blocked by adding isoform-specific antibodies to TGF-beta1, -beta2 and -beta3, indicating TGF-beta autoregulation. Despite these marked responses, there were no significant differences in the TGF-beta expression between normal and psoriatic fibroblasts. CONCLUSIONS: These results suggest that antiproliferative and anti-inflammatory effects of 1,25(OH)2D3 on psoriatic lesional skin may be mediated, at least in part, by a complex TGF-beta regulation in local dermal fibroblasts.