Cell-type and sex-specific rhythmic gene expression in the nucleus accumbens.

Circadian rhythms are critical for human health and are highly conserved across species. Disruptions in these rhythms contribute to many diseases, including psychiatric disorders. Previous results suggest that circadian genes modulate behavior through specific cell types in the nucleus accumbens (NAc), particularly dopamine D1-expressing medium spiny neurons (MSNs). However, diurnal rhythms in transcript expression have not been investigated in NAc MSNs. In this study we identified and characterized rhythmic transcripts in D1- and D2-expressing neurons and compared rhythmicity results to homogenate as well as astrocyte samples taken from the NAc of male and female mice. We find that all cell types have transcripts with diurnal rhythms and that top rhythmic transcripts are largely core clock genes, which peak at approximately the same time of day in each cell type and sex. While clock-controlled rhythmic transcripts are enriched for protein regulation pathways across cell type, cell signaling and signal transduction related processes are most commonly enriched in MSNs. In contrast to core clock genes, these clock-controlled rhythmic transcripts tend to reach their peak in expression about 2-h later in females than males, suggesting diurnal rhythms in reward may be delayed in females. We also find sex differences in pathway enrichment for rhythmic transcripts peaking at different times of day. Protein folding and immune responses are enriched in transcripts that peak in the dark phase, while metabolic processes are primarily enriched in transcripts that peak in the light phase. Importantly, we also find that several classic markers used to categorize MSNs are rhythmic in the NAc. This is critical since the use of rhythmic markers could lead to over- or under-enrichment of targeted cell types depending on the time at which they are sampled. This study greatly expands our knowledge of how individual cell types contribute to rhythms in the NAc.

Psoriasis is associated with low serum levels of hydrogen sulfide, a potential anti-inflammatory molecule.

Psoriasis, characterized by circumscribed, red, thickened plaques with an overlying silver-white scale, is a common T-cell-mediated chronic inflammatory skin disease. Although hydrogen sulfide (H(2)S) has been shown to be a signaling molecule with both pro- or anti-inflammatory effects, its relationship with psoriasis has not been elucidated. In the present study, 15 patients with chronic progressive psoriasis and 15 healthy volunteers were investigated. Serum H(2)S levels in psoriasis patients were significantly lower than those of healthy controls (16.69 ± 5.47 µM vs. 34.5 ± 6.39 µM). In contrast, serum levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8) were significantly higher in psoriasis patients than healthy controls (22.88 ± 6.24 pg/ml vs. 12.07 ± 3.68 pg/ml; 61.47 ± 8.21 pg/ml vs. 31.54 ± 13.73 pg/ml; and 39.43 ± 8.56 pg/ml vs. 20.55 ± 6.45 pg/ml, respectively). The serum H(2)S levels negatively correlated with clinical disease severity. Furthermore, treatment of HaCaT human keratinocytes with TNF-α increased the levels of nitric oxide (NO), IL-6 and IL-8 (32.21 ± 5.71 µM vs. 3.22 ± 0.98 µM; 203.96 ± 13.16 pg/ml vs. 13.57 ± 3.75 pg/ml; and 301.24 ± 30.17 pg/ml vs. 29.06 ± 10.91 pg/ml, respectively) in the culture media. Exogenous H(2)S inhibited the TNF-α-mediated upregulation of NO, IL-6 and IL-8 in a dose-dependent manner. In addition, H(2)S inhibited TNF-α-mediated activation of p38, extracellular-signal-regulated kinase and nuclear factor kappa B. In conclusion, H(2)S may play a protective role in the pathogenesis of psoriasis. H(2)S-releasing agents may be promising therapeutics for psoriasis.

Characterization of DNA antigens from immune complexes deposited in the skin of patients with systemic lupus erythematosus.

BACKGROUND: Skin lesions are common manifestations in systemic lupus erythematosus (SLE). It is still unknown what the definite pathogenesis of skin involvement was and whether DNA participated in it. Our study was designed to explore the pathogenetic role and nature of nuclear antigen (DNA) deposited in the skin lesions of patients with SLE. METHODS: Thirty skin samples from patients with SLE and 2 normal skin samples were studied. Extracellular DNA was evaluated by indirect immunofluorescence methods. The deposited immune complexes were extracted by cryoprecipitation, and DNA was then isolated with phenol and chloroform. DNA fragment sizes were detected by agarose gel electrophoresis. Finally, 8 different probes were used to analyze the origin of these DNA molecules using Dot hybridization. RESULTS: Extracellular DNA staining was found only in skin lesions, mainly those located in the basement membrane zone, vascular wall, and hair follicle wall. Normal skin and non-lesion SLE skin showed no fluorescence at locations outside the nuclei. There were no differences in the rate and intensity of extracellular DNA staining when comparing active phase to remission phase patients. No relationship was found between extracellular DNA and circulating anti-dsDNA antibodies. Deposited DNA fragments clustered into four bands of somewhat discrete sizes: 20 000 bp, 1300 bp, 800-900 bp, 100-200 bp. Small sized fragments (100-200 bp) were positively correlated with disease activity (P < 0.05, r = 0.407). Dot hybridization showed significant homology of the various extracellular DNA fragments examined with human genomic DNA, but not with DNA from the microorganisms and viruses we examined. There were also homologies between DNA samples from different individuals. CONCLUSIONS: DNA and its immune complexes may contribute to the pathogenesis of skin lesions in SLE. These DNA molecules range in size from 100 bp to 20 kb and may be endogenous in origin.

Good response in a patient with deep-seated subcutaneous ulcer due to Candida species.

Deep-seated subcutaneous ulcers infected with Candida species are rare. We are reporting a 51-year-old Cantonese woman who had a large, deep-seated subcutaneous ulcer on her right shoulder for more than a year. Direct smears of the purulent extrusion revealed many pseudohyphae and yeast cells. Candida species were isolated from the purulent extrusion and further identified as Candida albicans and C. parapsilosis. A skin lesion biopsy contained yeast cells and pseudohyphae. C. parapsilosis were once isolated from the biopsy specimen. Total healing was obtained with itraconazole (200 mg twice daily for 16 days and then 100 mg twice daily for 14 days) combined with phototherapy.