Project description:Photoautotrophically grown wild type Chlamydomonas reinhardtii cultures were either "treated" with 2uM rose bengal at 50 umol photons m-2 s-1 or "untreated" with the same volume of water at the same light intensity. The purpose is to identify genes that are regulated by singlet oxygen. Keywords: stress response
Project description:Anti-TNF-alpha therapy has made a significant impact on the treatment of psoriasis. Despite being designed to neutralize TNF-alpha activity, the mechanism of action of these agents in the resolution of psoriasis remains unclear. The aim of this study was to better understand the mechanism of action of etanercept by examining very early changes in the lesional skin of psoriasis patients. 20 chronic plaque psoriasis patients were enrolled and received 50mg etanercept twice weekly. Skin biopsies were obtained before treatment and on days 1, 3, 7 and 14 post-treatment. Skin mRNA expression was analysed by microarray. Twenty individuals with chronic plaque psoriasis were enrolled (age range 18-75 years). Entry criteria included age greater than 18 years and stable plaque-type psoriasis involving at least 10% body surface area. Exclusion criteria included use of systemic psoriasis therapy within 4 weeks, topical therapy within 2 weeks, or severe co-morbid diseases. For 12 weeks, subjects received etanercept (Enbrel) 50mg twice a week subcutaneously. At baseline, 6 mm punch biopsies were obtained under local anaesthesia (lidocaine) from uninvolved skin and a target plaque. Subsequent biopsies were taken on days 1, 3, 7 and 14 of therapy from the same target plaque.
Project description:Arabidopsis thaliana cell suspension cultures (ACSC) were subjected to 30-min, mild chemical treatments with three different singlet oxygen elicitors at low-medium light conditions (150 µE m–2 s–1) with the aim of getting a better understanding of singlet oxygen-mediated defence responses in plants. The three elicitors Indigo Carmine (IC), Methylene Violet (MV) and Rose Bengal (RB) at a concentration of 0.5 µM were chosen because they exhibited different abilities to permeate the plasma membrane and to accumulate in the cell soma or organelles such as chloroplasts. In addition, ACSC were treated with 500 µM H2O2 for comparison. Confocal image analysis of Arabidopsis cells revealed that IC was not retained in cells, whereas MV and RB permeated the plasma membrane and accumulated in the chloroplast envelope and inside chloroplasts, respectively. As a consequence of their different cellular location, the physiological, transcriptional and photosynthetic responses of Arabidopsis cells to singlet oxygen production varied from each other and the activation of programmed cell death (PCD) was observed in ACSC treated with 0.5 µM RB, but not with the other elicitor nor with 500 µM H2O2. The role of chloroplasts in the activation of PCD was further investigated when this physiological response was analyzed in dark-grown cell cultures containing undifferentiated plastids. Interestingly, PCD was only activated in light-grown, but not in dark-grown, Arabidopsis cell cultures, suggesting that singlet oxygen-mediated defence responses were initiated inside chloroplasts. Genome-wide transcriptional profile analyses were performed as well and the results proved that there were only statistically significant changes in the transcript expression of light-grown ACSC treated with 0.5 µM RB and 500 µM H2O2, but not with IC nor with MV. Functional enrichment analyses revealed that GO/Biological process terms associated with defence responses were common in the treatments with 0.5 µM RB and 500 µM H2O2; however, resistance response to pathogen and PCD terms were only significantly over-represented in the RB treatment. Moreover, the analysis of the up-regulated transcripts in ACSC treated with 0.5 µM RB brought out that both specific markers for singlet oxygen from the conditional fluorescence (flu) mutant of Arabidopsis and transcripts with a key role in hormone-activated PCD (i.e. ethylene and jasmonic acid) were present, although there was no evidence for the up-regulation of EDS1 encoding the ENHANCED DISEASE SUSCEPTIBILITY PROTEIN 1. Finally, a co-regulation analysis proved that ACSC treated with 0.5 µM RB exhibited higher correlation with the flu family mutants than with other singlet oxygen producer mutants of Arabidopsis or wild-type plants of Arabidopsis subjected to high light treatments, where singlet oxygen was produced in photosystem II and an acclimatory response was activated instead of PCD. 18 Samples total. Six Samples are controls, 3 Samples each treated with Rose Bengal, Hydrogen Peroxide, Methyl Violet, and Indigo Carmine.
Project description:Psoriasis is a chronic inflammatory skin disease characterized by marked proliferation of keratinocytes leading to pronounced epidermal hyperplasia, elongation of rete ridges and hyperkeratosis. The most common form of psoriasis, chronic plaque psoriasis (Psoriasis vulgaris), involves relatively stable occurrence and progression of sharply demarcated lesions, usually on the trunk and extremities, which share a combination of trademark histological features, including tortuous and dilated dermal capillaries, loss of the epidermal granular layer, and accumulation of neutrophils beneath parakeratotic scale. In this study, whole-genome transcriptional profiling was used to characterize gene expression in 4 lesional and uninvolved skin samples obtained from patients with stable chronic plaque psoriasis. Skin mRNA expression was analysed by microarray. Four individuals with chronic plaque psoriasis were enrolled. 6 mm punch biopsies were obtained under local anaesthesia (lidocaine) from uninvolved skin and a target plaque.
Project description:Psoriasis is a chronic inflammatory skin disorder that is predominantly characterized by sharply demarcated chronic erythematous plaques. Although its etiological mechanisms are largely unknown, recent evidence suggests that the topical application of imiquimod (IMQ) cream causes psoriasis-like skin inflammation in humans and mice. Skin examined 4 hours after IMQ cream treatment. Results provide insight into the role of each knockout mice phenotype in the response to IMQ-induced psoriasis model.