Potentiation of tumor necrosis factor-induced NF-kappa B activation by deacetylase inhibitors is associated with a delayed cytoplasmic reappearance of I kappa B alpha.

Previous studies have implicated acetylases and deacetylases in regulating the transcriptional activity of NF-kappa B. Here, we show that inhibitors of deacetylases such as trichostatin A (TSA) and sodium butyrate (NaBut) potentiated TNF-induced expression of several natural NF-kappa B-driven promoters. This transcriptional synergism observed between TNF and TSA (or NaBut) required intact kappa B sites in all promoters tested and was biologically relevant as demonstrated by RNase protection on two instances of endogenous NF-kappa B-regulated gene transcription. Importantly, TSA prolonged both TNF-induced DNA-binding activity and the presence of NF-kappa B in the nucleus. We showed that the p65 subunit of NF-kappa B was acetylated in vivo. However, this acetylation was weak, suggesting that other mechanisms could be implicated in the potentiated binding and transactivation activities of NF-kappa B after TNF plus TSA versus TNF treatment. Western blot and immunofluorescence confocal microscopy experiments revealed a delay in the cytoplasmic reappearance of the I kappa B alpha inhibitor that correlated temporally with the prolonged intranuclear binding and presence of NF-kappa B. This delay was due neither to a defect in I kappa B alpha mRNA production nor to a nuclear retention of I kappa B alpha but was rather due to a persistent proteasome-mediated degradation of I kappa B alpha. A prolongation of I kappa B kinase activity could explain, at least partially, the delayed I kappa B alpha cytoplasmic reappearance observed in presence of TNF plus TSA.

Transcription factor binding sites in the pol gene intragenic regulatory region of HIV-1 are important for virus infectivity.

We have previously identified in the pol gene of human immunodeficiency virus type 1 (HIV-1) a new positive transcriptional regulatory element (nt 4481-4982) containing recognition sites for nuclear proteins (sites B, C, D and a GC-box) [C. Van Lint, J. Ghysdael, P. Paras, Jr, A. Burny and E. Verdin (1994) J. Virol. 68, 2632-2648]. In this study, we have further physically characterized each binding site and have shown that the transcription factors Oct-1, Oct-2, PU.1, Sp1 and Sp3 interact in vitro with the pol region. Chromatin immunoprecipitation assays using HIV-infected cell lines demonstrated in the context of chromatin that Sp1, Sp3, Oct-1 and PU.1 are recruited to the HS7 region in vivo. For each site, we have identified mutations abolishing factor binding to their cognate DNA sequences without altering the underlying amino acid sequence of the integrase. By transient transfection assays, we have demonstrated the involvement of the pol binding sites in the transcriptional enhancing activity of the intragenic region. Our functional results with multimerized wild-type and mutated pol binding sites separately (i.e. in the absence of the other sites) have demonstrated that the PU.1, Sp1, Sp3 and Oct-1 transcription factors regulate the transcriptional activity of a heterologous promoter through their respective HS7 binding sites. Finally, we have investigated the physiological role of the HS7 binding sites in HIV-1 replication and have shown that these sites are important for viral infectivity.

Vascularity and fractal dimension of the dermo-epidermal interface in guttate and plaque-type psoriasis.

BACKGROUND: Histological structures of the skin are often irregular in size and shape. Euclidean geometry and fractal analysis are complementary for assessing distinct aspects of their dimensions. OBJECTIVE: To determine and compare the variations in shape of the dermo-epidermal junction and the size of the superficial vessels in psoriatic lesions. METHOD: The relative microvasculature area and the fractal dimension D of the dermo-epidermal interface were measured inside and outside growth-stunted guttate lesions (n = 22) and expanding plaques (n = 37) in psoriasis of the trunk. RESULTS: The median D values of the dermo-epidermal interface were significantly larger (p < 0.01) in psoriatic plaques (D = 1.15) than in guttate lesions (D = 1.08), and these D values on lesional skin were significantly larger (p < 0.01) than in the uninvolved skin (D = 1.03). The microvasculature was significantly (p < 0.01) more developed in lesional (plaque: 13%, guttate: 8.20%) than in uninvolved skin (3.60 and 3.85%). No correlations were found between the relative microvasculature areas and the D values of the dermo-epidermal interface, both in the uninvolved and lesional skins of each psoriatic type. CONCLUSION: The absence of a relationship between modulations of the dermo-epidermal junction and vascular hyperplasia, both in expanding and stable psoriasis lesions, suggests that these events are regulated by different mechanisms and do not depend on each other.

A multicenter randomized trial of ketoconazole 2% and zinc pyrithione 1% shampoos in severe dandruff and seborrheic dermatitis.

Ketoconazole (KET) and zinc pyrithione (ZPT) are compounds active against the Malassezia spp. yeasts, which are believed to play a major role in dandruff and seborrheic dermatitis. We compared the efficacy and safety of KET 2% and ZPT 1% in shampoo formulations for the alleviation of severe dandruff and seborrheic dermatitis. This open randomized, parallel-group trial began with a 2-week run-in phase during which subjects applied a neutral non-antidandruff shampoo. It was followed by a 4-week randomized treatment phase and a subsequent 4-week follow-up phase without treatment. Shampooing during the treatment period was carried out twice weekly for the KET group and at least twice weekly for the ZPT group in accordance with the label instructions. A total of 343 subjects were recruited to enter the trial. Of the 331 eligible volunteers, 171 were randomized to KET 2% and 160 to ZPT 1%. Clinical assessments were performed. Beneficial effects were evidenced for both medicated shampoos, but the effect was significantly better for KET 2%, which achieved a 73% improvement in the total dandruff severity score compared with 67% for ZPT 1% at week 4 (p < 0.02). The recurrence rate of the disease was also significantly lower following KET 2% treatment than following ZPT 1% treatment. As a consequence, the overall clearing of the skin condition at the end of treatment and follow-up phase was in favor of the KET 2% formulation (p = 0.004). Side effects were minimal. It is concluded that after a 4-week treatment, KET 2% shampoo was significantly superior to ZPT 1% shampoo in the treatment of subjects with severe dandruff or seborrheic dermatitis of the scalp. It is our assumption that this difference is noticeable for the patient and as a consequence relevant. Both formulations were well tolerated.

Lymecycline and minocycline in inflammatory acne: a randomized, double-blind intent-to-treat study on clinical and in vivo antibacterial efficacy.

BACKGROUND: Some antibiotics represent a mainstay in acne treatment. However, studies comparing their efficacies are rare. AIM: To evaluate the clinical and in vivo antibacterial effect of lymecycline and minocycline at different dosages. METHOD: Eighty-six patients with moderate to severe acne were enrolled in a randomized, double-blind, intent-to-treat study comparing in three parallel groups the effect of (1) lymecycline 300 mg daily for 12 weeks, (2) minocycline 50 mg daily for 12 weeks and (3) minocycline 100 mg daily for 4 weeks followed by 50 mg daily for 8 weeks. Evaluations were made at the screening visit and at five on-treatment visits. They consisted of clinical counts of acne lesions and evaluations of bacterial viability using dual flow cytometry performed on microorganisms collected from sebaceous infundibula by cyanoacrylate strippings. RESULTS: Patients receiving minocycline 100/50 mg had the best clinical outcome, particularly in the reduction of the number of papules. By the end of the trial, the microbial response to minocycline 100/ 50 mg was also superior to either of the other two treatments. There were less live and more dead bacteria. CONCLUSION: In this trial, minocycline 100/50 mg was superior for the treatment of inflammatory acne when compared to lymecycline 300 mg and minocycline 50 mg.