Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By microarray assay we identified ESTs (expressed sequence tags) whose expression was predominantly increased in the affected skin of patients with psoriasis vulgaris. Among them, a full-length cDNA sequence corresponding to one of those ESTs (AI829641) was isolated by screening of cultured human keratinocyte cDNA libraries. This cDNA encodes a novel member of the Ly-6/uPAR superfamily, designated SLURP-2 (secreted Ly-6/uPAR related protein 2). SLURP-2 has an open reading frame of 97 amino acids containing 10 conserved cysteine residues. SLURP-2 has a single functional copy within the LY6 superfamily gene cluster at chromosome 8q24.3. RT-PCR (reverse transcriptase-polymerase chain reaction) expression analysis revealed that SLURP-2 was expressed in multiple tissues, mainly in the epithelial cells including the skin and keratinocytes, but not in spleen or bone marrow. Comparison of the expression of this gene among the psoriatic lesional and nonlesional skin of patients and the normal skin of healthy individuals detected by quantitative real-time RT-PCR analysis disclosed that SLURP-2 was up-regulated threefold in psoriatic lesional skin. These findings suggest that SLURP-2 may be involved in the pathophysiology of psoriasis through its role in keratinocyte hyperproliferation and/or T cell differentiation/activation.
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PMID:SLURP-2, a novel member of the human Ly-6 superfamily that is up-regulated in psoriasis vulgaris. 1257 58

Antimicrobial peptides of the beta-defensin family are expressed in all human epithelial tissues tested to date and have recently been the subject of vigorous investigation. Their localization and characteristics support the hypothesis that these peptides play a role in mucosal and skin defense. The lipophilic yeast Malassezia furfur is a saprophyte found in normal human cutaneous flora. Malassezia furfur is not only a saprophyte, but is also associated with several diseases such as Malassezia folliculitis, seborrheic dermatitis and some forms of atopic dermatitis, psoriasis and confluent and reticulate papillomatosis. Little is known about the mechanism by which M. furfur overcomes the natural barrier of the skin. To further define the role of the beta-defensins in the innate human skin immune response, we analyzed the mRNA expression of two human beta-defensins HBD-1 and HBD-2 in human keratinocytes treated with M. furfur. In addition, we looked into how M. furfur of TGF-beta1 and IL-10, cytokines that interfere with the development of protective cell immunity, regulate their expression. Finally, we examined the signal transduction mechanisms involved during M. furfur uptake. Cultured human keratinocytes were treated with M. furfur. The mRNA and protein expression were analyzed, respectively, by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. Our data demonstrate that M. furfur does not modify HBD-1 expression, whereas it up-regulates, via protein kinase C (PKC), the expression of HBD-2, TGFbeta-1 and IL-10 48 h after treatment. Our results suggest that beta-defensins are integral components of innate host defenses. They play an essential part in the resistance of the human skin surfaces against M. furfur uptake and other microbial invasion.
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PMID:Malassezia furfur induces the expression of beta-defensin-2 in human keratinocytes in a protein kinase C-dependent manner. 1496 22

Psoriasis is a chronic inflammatory skin disorder characterized by accumulation of Th1-type T cells and neutrophils, regenerative keratinocyte proliferation and differentiation, and enhanced epidermal production of antimicrobial peptides. The underlying cause is unknown, but there are some similarities with the immunologic defense program against bacteria. Development of psoriasiform skin lesions has been reported after administration of granulocyte colony-stimulating factor (G-CSF), a cytokine induced in monocytes by bacterial antigens. To further investigate the relation between this type of cytokine-induced dermatitis and psoriasis, we analyzed the cutaneous cytokine profile [tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, transforming growth factor-beta1 (TGF-beta1), interleukin-10 (IL-10), IL-12p35 and p40, and IL-8] and expression of markers of epidermal activation [Ki-67, cytokeratin-16, major histocompatibility complex (MHC) class II, intercellular adhesion molecule-1 (ICAM-1)] in a patient who developed G-CSF-induced psoriasiform dermatitis by using quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistology. The histologic picture resembled psoriasis with regard to epidermal hyperparakeratosis and the accumulation of lymphocytes in the upper corium. CD8(+) T cells were found to infiltrate the epidermis which was associated with an aberrant expression of Ki-67, cytokeratin-16, MHC class II, and ICAM-1 on adjacent keratinocytes. As compared to normal skin (n = 7), there was an increased expression of TNF-alpha, IL-12p40, and IL-8, a decreased expression of TGF-beta1, and a lack of IL-10, similar to the findings in active psoriasis (n = 8). Therefore, G-CSF may cause a lymphocytic dermatitis that, similar to psoriasis, is characterized by a pro-inflammatory Th1-type cytokine milieu and an epidermal phenotype indicative of aberrant maturation and acquisition of non-professional immune functions.
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PMID:Granulocyte colony-stimulating-factor-induced psoriasiform dermatitis resembles psoriasis with regard to abnormal cytokine expression and epidermal activation. 1518 19

To investigate the role of Interleukin-17 (IL-17), Interferon-gamma (IFN-gamma), and macrophage inflammatory protein-3 alpha (MIP-3alpha) in the pathogenesis of psoriasis, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to semi-quantitatively analyze the mRNA expression of IL-17, IFN-gamma, and MIP-3alpha in 31 psoriatic lesions and 16 normal skin tissues. The results showed that the mRNA of the three cytokines was present in all specimens. And the expression level of IL-17 mRNA in skin lesions was 1.1416 +/- 0.0591, which was significantly higher than that in normal controls (0.8788 +/- 0.0344, P<0.001). The expression levels of IFN-gamma mRNA were 1.1142 +/- 0.0561 and 0. 9050 +/- 0.0263, respectively, with significant difference (P<0.001). And the expression levels of MIP-3alpha mRNA in psoriatic lesions was 1.1397 +/- 0.0521, which was markedly higher than that in normal controls (0.8681 +/- 0.0308, P<0.001). These findings indicate that up-regulated expression of IL-17, IFN-gamma, and MIP-3alpha might be involved in the pathogenesis of psoriasis.
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PMID:The expression of interleukin-17, interferon-gamma, and macrophage inflammatory protein-3 alpha mRNA in patients with psoriasis vulgaris. 1531 54

S100 proteins are involved in many biological processes. S100A7 and S100A9 have been shown to be markedly upregulated both in ductal carcinoma in situ of the breast and in psoriasis. We have examined the relationship between keratinocyte differentiation and the expression of the two proteins. Using Western blot analysis and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), both S100A7 and S100A9 were shown to be induced in normal primary keratinocytes (HEKn), when differentiation was promoted by high extracellular calcium, loss of contact with extracellular matrix and confluent conditions, as previously reported for S100A7 in mammary epithelial cells. Differentiation was confirmed by using RT-PCR for the differentiation marker keratin-1. Using immunohistochemistry with monoclonal antibodies, we compared the expression of the two proteins in a spectrum of conditions of dysregulated keratinocyte differentiation. We found a strikingly similar distribution of the proteins. Their expression correlated with the degree of keratinocyte differentiation. They were both absent in undifferentiated basalioma and strongly expressed in carcinoma in situ, as well as in keratoacanthoma and differentiated squamous cell carcinoma. In normal epithelium, they were expressed in the superficial, differentiated region of the epithelium rather than in the basal region. These findings support the hypothesis that these two S100 proteins are involved in keratinocyte differentiation.
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PMID:Expression patterns of S100A7 (psoriasin) and S100A9 (calgranulin-B) in keratinocyte differentiation. 1574 May 87

Psoriasis is a benign, chronic skin disease characterized by keratinocyte hyperproliferation and abnormal differentiation. Telomerase is an enzyme-reverse transcriptase that protects chromosomes from degradation by stabilizing telomere length. Recent studies suggest that telomerase activity (TA) may be responsible in part for some of nonmalignant proliferative skin diseases. There is evidence that telomerase has an active anti-apoptotic role. TA in general is associated with cellular proliferation. We hypothesize a relationship between TA, keratinocyte proliferation and apoptosis in psoriatic skin lesions. The TA in telomere elongation makes keratinocyte hyperproliferation possible and is at the same time, one of its limiting factors. This hyperproliferation in psoriasis occurs as a result of significant keratinocyte damage caused by self-reactive T-cells through induction of various apoptotic pathways. On the other hand, TA in telomere elongation, together with other factors, has an active anti-apoptotic role, preserving the necessary amount of equilibrium between these two processes (apoptosis and proliferation) therefore being the main reason why conversion of a psoriatic plaque to squamous cell carcinoma is rare. As there is little data on TA in psoriatic lesions, in evaluation of our hypothesis we suggest thorough parallel studies of TA, telomere length, apoptosis and proliferation in psoriatic lesional skin on multiple checkpoints and targets, using more samples so the reliability of the results would be higher. This is important since a better understanding of these factors might provide new possible therapeutic targets.
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PMID:The role of telomerase activity in psoriatic skin lesions. 1711 16

In order to investigate the mRNA expression and function of interleukin-23 (p19/p40) and interleukin-12 (p35/p40) in the psoriatic lesion, no-lesion and normal human skin, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the expression of IL-23 (p19/p40) and IL-12 (p35/p40). The results showed that the expression of IL-23p19 mRNA and p40 (IL-12/IL-23) mRNA were higher in psoriatic lesion than those of non-lesional skin and normal skin. The levels of IL-23p19 mRNA and p40 (IL-12/IL-23) mRNA were higher in psoriatic non-lesional skin than normal skin. However, no significant difference was found in the level of IL-12p35 mRNA among the psoriatic lesional skin, non-lesional skin and normal skin. It was suggested that IL-23 might be more important in the pathogenesis of psoriasis than IL-12.
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PMID:The expression of interleukin-23 (p19/p40) and interleukin-12 (p35/p40) in psoriasis skin. 1735 9

In order to investigate the role of Th17 cytokines in the pathogenesis of psoriasis, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the expression of IL-17, IL-23 (p19/p40), and IL-6 in skin lesions and non-lesions of the patients with psoriasis and skin tissues of normal subjects. The results showed that the mRNA expression levels of IL-17, IL-23p19, IL-23p40 and IL-6 in psoriasis lesion were significantly higher than those of non-lesions (1.231 +/- 0.843 vs 1.003 +/- 0.044, 1.166 +/- 0.142 vs 0.765 +/- 0.133, 1.125 +/- 0.104 vs 0.730 +/- 0.103, 1.186 +/- 0.222 vs 0.976 +/- 0.122, respectively, all P < 0.05). Meanwhile, The expression levels of IL-17 mRNA, IL-23p19 mRNA, IL-23p40 mRNA and IL-6 mRNA were higher in non-lesions than those in normal skin tissues (1.003 +/- 0.044 vs 0.620 +/- 0.104, 0.765 +/- 0.133 vs 0.584 +/- 0.078, 0.730 +/- 0.103 vs 0.000 +/- 0.000, 0.976 +/- 0.122 vs 0.656 +/- 0.121, respectively, all P < 0.05). The overexpression of Th17 cytokines in the skin lesions of patients with psoriasis may indicate that Th17 cytokines play a very important role in the immunopathogenesis of psoriasis.
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PMID:Expression of Th17 cytokines in skin lesions of patients with psoriasis. 1764 55

Several reports have indicated that the chemokine receptor CCR5 and its ligands, especially CCL5 (formerly known as RANTES), may play a role in the pathogenesis of psoriasis. The purpose of this investigation was to examine the expression of CCR5 and its ligands in chronic plaque psoriasis and to evaluate the clinical and immunohistochemical effect of a CCR5 receptor inhibitor. Immunohistochemical analysis showed low but significant increased total numbers of CCR5 positive cells in epidermis and dermis of lesional skin in comparison to non-lesional skin. However, relative expression of CCR5 proportional to the cells observed revealed that the difference between lesional and non-lesional skin was only statistically significant in the epidermis for CD3 positive cells and in the dermis for CD68 positive cells. Quantification of mRNA by reverse transcriptase-polymerase chain reaction only showed an increased expression of CCL5 (RANTES) in lesional skin. A randomized placebo-controlled clinical trial in 32 psoriasis patients revealed no significant clinical effect and no changes at the immunohistochemical level comparing patients treated with placebo or a CCR5 inhibitor SCH351125. We conclude that although CCR5 expression is increased in psoriatic lesions, this receptor does not play a crucial role in the pathogenesis of psoriasis.
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PMID:Expression of the chemokine receptor CCR5 in psoriasis and results of a randomized placebo controlled trial with a CCR5 inhibitor. 1764 3

Heparin-binding EGF-like growth factor (HB-EGF) and amphiregulin (AREG) are the members of EGF family that bind to common EGF receptor (EGFR) in the epidermis. However, the role of these two growth factors in epidermal hyperplasia of psoriasis has not been established. On the other hand, CD4+ T cells are responsible for the development of the psoriatic plaques. However, inflammatory cytokines, such as TNFalpha, IL-1beta and IFNgamma, inhibit the growth of human keratinocytes in vitro. The expression of HB-EGF, AREG and EGFR proteins in normal (n = 22) and psoriatic (n = 34) skin tissues was examined by immunohistochemistry. Then, the effects of HB-EGF and AREG on the growth of cultured adult normal human epidermal keratinocytes (NHEK-AD) with or without TH1 cytokines, such as TNFalpha, IL-1beta and IFNgamma, were examined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, and the effects of these cytokines on the expression of EGFR mRNA in NHEK-AD were examined by real-time reverse transcriptase-polymerase chain reaction. The expression of HB-EGF and AREG in the epidermis was not specific to psoriatic plaques, but the distribution of positive cells throughout the epidermis was different between normal skins and psoriatic plaques. On the other hand, in the dermis and the papillary dermis, most of vascular endothelial cells and infiltrating mononuclear cells expressed both HB-EGF and AREG in normal skins and psoriatic plaques, and these positive cells were more frequent in psoriasis compared to normal skin. In the in vitro growth assay, HB-EGF, not AREG, stimulated the proliferation of NHEK-AD at the optimal concentration of 1 ng/ml. Furthermore, HB-EGF compensated the growth-suppressing effects of TNFalpha, IL-1beta and IFNgamma on NHEK-AD, and TNFalpha promoted the growth of NHEK-AD at the concentration of 2 and 20 U/ml in combination with HB-EGF and, in lesser extent, with AREG. However, TNFalpha did not affect the expression of EGFR mRNA in NHEK-AD. Growth factors and inflammatory cytokines produced in the dermis would be important for the epidermal proliferation in psoriatic plaques and TNFalpha may play a key role in cooperation with HB-EGF and AREG in the proliferation of epidermal keratinocytes at the psoriatic skin lesions.
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PMID:The role of heparin-binding EGF-like growth factor and amphiregulin in the epidermal proliferation of psoriasis in cooperation with TNFalpha. 1796 Apr


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