GJB5 association with BRAF mutation and survival in cutaneous malignant melanoma.

BACKGROUND: Gap-junctional intercellular communication is crucial for epidermal cellular homeostasis. Inability to establish melanocyte-keratinocyte contact and loss of the intercellular junction's integrity may contribute to melanoma development. Connexins, laminins and desmocollins have been implicated in the control of melanoma growth, where their reduced expression has been reported in metastatic lesions. OBJECTIVES: The aim of this study was to investigate connexin 31·1 (GJB5) expression and identify any association with BRAF mutational status, prognosis of patients with melanoma and mitogen-activated protein kinase (MAPK) inhibitor (MAPKi) treatment. METHODS: GJB5 expression was measured at RNA and protein level in melanoma clinical samples and established cell lines treated (or not) with BRAF and MEK inhibitors (MEKi), as well as in cell lines which developed MAPKi resistance. Findings were further validated and confirmed by analysis of independent datasets. RESULTS: Our analysis reveals significant downregulation of GJB5 expression in metastatic melanoma lesions compared with primary ones and in BRAF-mutated vs. BRAF-wildtype (BRAFWT ) melanomas. Likewise, GJB5 expression is significantly lower in BRAFV600E compared with BRAFWT cell lines and increases on MAPKi treatment. MAPKi-resistant melanoma cells display a similar expression pattern compared with BRAFWT cells, with increased GJB5 expression associated with morphological changes. Enhancement of BRAFV600E expression in BRAFWT melanoma cells significantly upregulates miR-335-5p expression with consequent downregulation of GJB5, one of its targets. Furthermore, overexpression of miR-335-5p in two BRAFWT cell lines confirms specific GJB5 protein downregulation. Reverse transcriptase quantitative polymerase chain reaction analysis also revealed upregulation of miR-335 in BRAFV600E melanoma cells, which is significantly downregulated in cells resistant to MEKi. Our data were further validated using the TCGA_SKCM dataset, where BRAF mutations associate with increased miR-335 expression and inversely correlate with GJB5 expression. In clinical samples, GJB5 underexpression is also associated with patient overall worse survival, especially at early stages. CONCLUSIONS: We identified a significant association between metastases/BRAF mutation and low GJB5 expression in melanoma. Our results identify a novel mechanism of gap-junctional protein regulation, suggesting a prognostic role for GJB5 in cutaneous melanoma.

Prevalence and incidence of osteoporotic fractures in patients on long-term glucocorticoid treatment for rheumatic diseases: the Glucocorticoid Induced OsTeoporosis TOol (GIOTTO) study.

Osteoporosis and fractures are common and invalidating consequences of chronic glucorticoid (GC) treatment. Reliable information regarding the epidemiology of GC induced osteoporosis (GIOP) comes exclusively from the placebo group of randomized clinical trials while observational studies are generally lacking data on the real prevalence of vertebral fractures, GC dosage and primary diagnosis. The objective of this study was to evaluate the prevalence and incidence of osteoporotic fractures and to identify their major determinants (primary disease, GC dosage, bone mineral density, risk factors, specific treatment for GIOP) in a large cohort of consecutive patients aged >21 years, on chronic treatment with GC (≥5 mg prednisone - PN - equivalent) and attending rheumatology centers located all over Italy. Glucocorticoid Induced OsTeoporosis TOol (GIOTTO) is a national multicenter cross-sectional and longitudinal observational study. 553 patients suffering from Rheumatoid Arthritis (RA), Polymyalgia Rheumatica (PMR) and Connective Tissue Diseases (CTDs) and in chronic treatment with GCs were enrolled. Osteoporotic BMD values (T score <-2.5) were observed in 28%, 38% and 35% of patients with CTDs, PMR or RA at the lumbar spine, and in 18%, 29% and 26% at the femoral neck, respectively. Before GC treatment, prevalent clinical fractures were reported by 12%, 37% and 17% of patients with CTDs, PMR, or RA, respectively. New clinical fragility fractures during GC treatment were reported by 12%, 10% and 23% of CTDs, PMR and RA patients, respectively. Vertebral fractures were the prevailing type of fragility fracture. More than 30% of patients had recurrence of fracture. An average of 80% of patients were in supplementation with calcium and/or vitamin D during treatment with GCs. Respectively, 64%, 80%, and 72% of the CTDs, PMR and RA patients were on pharmacological treatment for GIOP, almost exclusively with bisphosphonates. The GIOTTO study might provide relevant contributions to clinical practice, in particular by highlighting and quantifying in real life the prevalence of GIOP and relative fractures, the frequency of the main risk factors, and the currently sub-optimal prevention. Moreover, these results emphasize the importance of the underlying rheumatic disease on the risk of GIOP associated fractures.

Transcriptional Signatures of Sleep Duration Discordance in Monozygotic Twins.

Introduction: Habitual short sleep duration is associated with adverse metabolic, cardiovascular, and inflammatory effects. Co-twin study methodologies account for familial (eg, genetics and shared environmental) confounding, allowing assessment of subtle environmental effects, such as the effect of habitual short sleep duration on gene expression. Therefore, we investigated gene expression in monozygotic twins discordant for actigraphically phenotyped habitual sleep duration. Methods: Eleven healthy monozygotic twin pairs (82% female; mean age 42.7 years; SD = 18.1), selected based on subjective sleep duration discordance, were objectively phenotyped for habitual sleep duration with 2 weeks of wrist actigraphy. Peripheral blood leukocyte (PBL) RNA from fasting blood samples was obtained on the final day of actigraphic measurement and hybridized to Illumina humanHT-12 microarrays. Differential gene expression was determined between paired samples and mapped to functional categories using Gene Ontology. Finally, a more comprehensive gene set enrichment analysis was performed based on the entire PBL transcriptome. Results: The mean 24-hour sleep duration of the total sample was 439.2 minutes (SD = 46.8 minutes; range 325.4-521.6 minutes). Mean within-pair sleep duration difference per 24 hours was 64.4 minutes (SD = 21.2; range 45.9-114.6 minutes). The twin cohort displayed distinctive pathway enrichment based on sleep duration differences. Habitual short sleep was associated with up-regulation of genes involved in transcription, ribosome, translation, and oxidative phosphorylation. Unexpectedly, genes down-regulated in short sleep twins were highly enriched in immuno-inflammatory pathways such as interleukin signaling and leukocyte activation, as well as developmental programs, coagulation cascade, and cell adhesion. Conclusions: Objectively assessed habitual sleep duration in monozygotic twin pairs appears to be associated with distinct patterns of differential gene expression and pathway enrichment. By accounting for familial confounding and measuring real life sleep duration, our study shows the transcriptomic effects of habitual short sleep on dysregulated immune response and provides a potential link between sleep deprivation and adverse metabolic, cardiovascular, and inflammatory outcomes.

A Novel Multi-step Virtual Screening for the Identification of Human and Mouse mPGES-1 Inhibitors.

We present here the development of a novel virtual screening protocol combining Structure-based and Ligand-based drug design approaches for the identification of mouse mPGES-1 inhibitors. We used the existing 3D structural data of the murine enzyme to hypothesize the inhibitors binding mode, which was the starting point for docking simulations, shape screening, and pharmacophore hypothesis screening. The protocol allowed the identification of 16 mouse mPGES-1 inhibitors with low micromolar activity, which, notably, also inhibit the human enzyme in the same concentration range. The inhibitors predicted binding mode is expected to be the base for the rational drug design of new potent dual species inhibitors of human and murine mPGES-1.

Interplay of Surface and Dirac Plasmons in Topological Insulators: The Case of Bi_{2}Se_{3}.

We have investigated plasmonic excitations at the surface of Bi_{2}Se_{3}(0001) via high-resolution electron energy loss spectroscopy. For low parallel momentum transfer q_{∥}, the loss spectrum shows a distinctive feature peaked at 104 meV. This mode varies weakly with q_{∥}. The behavior of its intensity as a function of primary energy and scattering angle indicates that it is a surface plasmon. At larger momenta (q_{∥}~0.04 Å^{-1}), an additional peak, attributed to the Dirac plasmon, becomes clearly defined in the loss spectrum. Momentum-resolved loss spectra provide evidence of the mutual interaction between the surface plasmon and the Dirac plasmon of Bi_{2}Se_{3}. The proposed theoretical model accounting for the coexistence of three-dimensional doping electrons and two-dimensional Dirac fermions accurately represents the experimental observations. The results reveal novel routes for engineering plasmonic devices based on topological insulators.

High-Q resonant cavities for terahertz quantum cascade lasers.

We report on the realization and characterization of two different designs for resonant THz cavities, based on wire-grid polarizers as input/output couplers, and injected by a continuous-wave quantum cascade laser (QCL) emitting at 2.55 THz. A comparison between the measured resonators parameters and the expected theoretical values is reported. With achieved quality factor Q ≈ 2.5 × 10(5), these cavities show resonant peaks as narrow as few MHz, comparable with the typical Doppler linewidth of THz molecular transitions and slightly broader than the free-running QCL emission spectrum. The effects of the optical feedback from one cavity to the QCL are examined by using the other cavity as a frequency reference.

Photodetectors based on graphene, other two-dimensional materials and hybrid systems.

Graphene and other two-dimensional materials, such as transition metal dichalcogenides, have rapidly established themselves as intriguing building blocks for optoelectronic applications, with a strong focus on various photodetection platforms. The versatility of these material systems enables their application in areas including ultrafast and ultrasensitive detection of light in the ultraviolet, visible, infrared and terahertz frequency ranges. These detectors can be integrated with other photonic components based on the same material, as well as with silicon photonic and electronic technologies. Here, we provide an overview and evaluation of state-of-the-art photodetectors based on graphene, other two-dimensional materials, and hybrid systems based on the combination of different two-dimensional crystals or of two-dimensional crystals and other (nano)materials, such as plasmonic nanoparticles, semiconductors, quantum dots, or their integration with (silicon) waveguides.

PATZ1 interacts with p53 and regulates expression of p53-target genes enhancing apoptosis or cell survival based on the cellular context.

PATZ1 is a transcriptional factor functioning either as an activator or a repressor of gene transcription depending upon the cellular context. It appears to have a dual oncogenic/anti-oncogenic activity. Indeed, it is overexpressed in colon carcinomas, and its silencing inhibits colon cancer cell proliferation or increases sensitivity to apoptotic stimuli of glioma cells, suggesting an oncogenic role. Conversely, the development of B-cell lymphomas, sarcomas, hepatocellular carcinomas and lung adenomas in Patz1-knockout (ko) mice supports its tumour suppressor function. PATZ1 role in mouse lymphomagenesis is mainly because of the involvement of PATZ1 in BCL6-negative autoregulation. However, this does not exclude that PATZ1 may be involved in tumorigenesis by other mechanisms. Here, we report that PATZ1 interacts with the tumour suppressor p53 and binds p53-dependent gene promoters, including those of BAX, CDKN1A and MDM2. Knockdown of PATZ1 in HEK293 cells reduces promoter activity of these genes and inhibits their expression, suggesting a role of PATZ in enhancing p53 transcriptional activity. Consistently, Patz1-ko mouse embryonic fibroblasts (MEFs) show decreased expression of Bax, Cdkn1a and Mdm2 compared with wild-type (wt) MEFs. Moreover, Patz1-ko MEFs show a decreased percentage of apoptotic cells, either spontaneous or induced by treatment with 5-fluorouracil (5FU), compared with wt controls, suggesting a pro-apoptotic role for PATZ1 in these cells. However, PATZ1 binds p53-target genes also independently from p53, exerting, in the absence of p53, an opposite function on their expression. Indeed, knockdown of PATZ1 in p53-null osteosarcoma cells upregulates BAX expression and decreases survival of 5FU-treated cells, then suggesting an anti-apoptotic role of PATZ1 in p53-null cancer cells. Therefore, these data support a PATZ1 tumour-suppressive function based on its ability to enhance p53-dependent transcription and apoptosis. Conversely, its opposite and anti-apoptotic role in p53-null cancer cells provides the perspective of PATZ1 silencing as a possible adjuvant in the treatment of p53-null cancer.

Intrinsic stability of quantum cascade lasers against optical feedback.

We study the time dependence of the optical power emitted by terahertz and mid-IR quantum cascade lasers in presence of optical reinjection and demonstrate unprecedented continuous wave (CW) emission stability for strong feedback. We show that the absence of coherence collapse or other CW instabilities typical of diode lasers is inherently associated with the high value of the photon to carrier lifetime ratio and the negligible linewidth enhancement factor of quantum cascade lasers.

Nanometer size field effect transistors for terahertz detectors.

Nanometer size field effect transistors can operate as efficient resonant or broadband terahertz detectors, mixers, phase shifters and frequency multipliers at frequencies far beyond their fundamental cut-off frequency. This work is an overview of some recent results concerning the application of nanometer scale field effect transistors for the detection of terahertz radiation.

Nanowire-based field effect transistors for terahertz detection and imaging systems.

The development of self-assembled nanostructure technologies has recently opened the way towards a wide class of semiconductor integrated devices, with progressively optimized performances and the potential for a widespread range of electronic and photonic applications. Here we report on the development of field effect transistors (FETs) based on semiconductor nanowires (NWs) as highly-sensitive room-temperature plasma-wave broadband terahertz (THz) detectors. The electromagnetic radiation at 0.3 THz is funneled onto a broadband bow-tie antenna, whose lobes are connected to the source and gate FET electrodes. The oscillating electric field experienced by the channel electrons, combined with the charge density modulation by the gate electrode, results in a source-drain signal rectification, which can be read as a DC signal output. We investigated the influence of Se-doping concentration of InAs NWs on the detection performances, reaching responsivity values higher than 100 V W⁻¹, with noise-equivalent-power of ∼10⁻9 W Hz(⁻½). Transmission imaging experiments at 0.3 THz show the good reliability and sensitivity of the devices in a real practical application.

Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers.

Optical frequency comb synthesizers have represented a revolutionary approach to frequency metrology, providing a grid of frequency references for any laser emitting within their spectral coverage. Extending the metrological features of optical frequency comb synthesizers to the terahertz domain would be a major breakthrough, due to the widespread range of accessible strategic applications and the availability of stable, high-power and widely tunable sources such as quantum cascade lasers. Here we demonstrate phase-locking of a 2.5 THz quantum cascade laser to a free-space comb, generated in a LiNbO(3) waveguide and covering the 0.1-6 THz frequency range. We show that even a small fraction (<100 nW) of the radiation emitted from the quantum cascade laser is sufficient to generate a beat note suitable for phase-locking to the comb, paving the way to novel metrological-grade terahertz applications, including high-resolution spectroscopy, manipulation of cold molecules, astronomy and telecommunications.

Graphene field-effect transistors as room-temperature terahertz detectors.

The unique optoelectronic properties of graphene make it an ideal platform for a variety of photonic applications, including fast photodetectors, transparent electrodes in displays and photovoltaic modules, optical modulators, plasmonic devices, microcavities, and ultra-fast lasers. Owing to its high carrier mobility, gapless spectrum and frequency-independent absorption, graphene is a very promising material for the development of detectors and modulators operating in the terahertz region of the electromagnetic spectrum (wavelengths in the hundreds of micrometres), still severely lacking in terms of solid-state devices. Here we demonstrate terahertz detectors based on antenna-coupled graphene field-effect transistors. These exploit the nonlinear response to the oscillating radiation field at the gate electrode, with contributions of thermoelectric and photoconductive origin. We demonstrate room temperature operation at 0.3 THz, showing that our devices can already be used in realistic settings, enabling large-area, fast imaging of macroscopic samples.

[Type I cryoglobulinemia with a fatal outcome]. / Crioglobulinemia tipo I de desenlace fatal.

Type I cryoglobulinemia, a condition associated with lymphoproliferative disorders, is caused by monoclonal immunoglobulins that precipitate at low temperatures. It mostly involves the skin and pathology study shows no signs of vasculitis. Management is usually based on immunosuppressive drugs associated with plasmapheresis for severe disease. The use of rituximab has recently been described for resistant cases. We present an unusual case of long-standing type I cryoglobulinemia associated with a monoclonal gammopathy of unknown significance. The patient developed extremely severe skin lesions with histological signs of vasculitis. The patient died due to the onset of noncutaneous manifestations of the cryoglobulinemia and complications of the immunosuppressive treatment.

G2 as an emerging rotavirus strain in pediatric gastroenteritis in southern Italy.

BACKGROUND: Human rotaviruses (HRVs) represent a major cause of acute gastroenteritis in children worldwide. It is estimated that they are responsible for a large number of diarrhea-associated hospitalizations in childhood each year. In Italy, limited data are available on the patterns of distribution of HRV G and P types. We report here the results of 2 years of rotavirus strain surveillance among children with severe gastroenteritis diagnosed in the town of Portici, Campania, southern Italy. METHODS: A total of 421 stool specimens from children between 6 months and 5 years of age and presenting acute diarrhea were collected and tested by routine diagnostic tests for HRV, adenovirus, astrovirus, norovirus, and common bacterial pathogens. RESULTS: The laboratory results showed that 110 of the 225 (26.1%) virus-positive samples contained HRVs. The different G and P rotavirus genotypes were analyzed by polymerase chain reaction (PCR). Among the VP7 genotypes identified, G1 and G2 were predominant, with percentages of 48.2 and 30.9%, respectively. G4, G9, and G10 were detected in a minority of cases. Among the VP4 genotypes, P[8] occurred the most frequently (56.4%), followed by P[4] (31.8%), and only a few P[10] and P[11] at percentages of 1.8 and 0.9%, respectively. CONCLUSION: Our epidemiological data of HRV strains will contribute to assessing the magnitude of the problem of HRV in the south of Italy.

Sleep, ghrelin, leptin and changes in body weight during a 1-year moderate-intensity physical activity intervention.

OBJECTIVE: To investigate cross-sectional and longitudinal relationships among exercise, sleep, ghrelin and leptin. METHODS: We randomly assigned 173 post-menopausal sedentary overweight (body mass index >or=24.0 kg/m(2) and >33% body fat) women aged 50-75 years living in western Washington State to either a facility- and home-based moderate-intensity physical activity intervention or a stretching control group. Fasting plasma ghrelin, leptin, measured height, weight and self-reported sleep were assessed at baseline and 12 months. RESULTS: There were no consistent cross-sectional patterns between self-reported sleep measures and ghrelin or leptin at baseline. The weight loss differences between exercisers and stretchers were greater for those who slept less at follow-up than at baseline compared to those whose sleep duration did not change (-3.2 kg, 95% confidence interval (CI) -5.8, -0.5). Improvements in sleep quality were associated with significantly greater differences between exercisers and stretchers for ghrelin increases (improved vs same sleep quality: +115 pg/ml, 95% CI +25, +206) and leptin decreases (improved vs worsened sleep quality: -5.7 ng/ml, 95% CI -9.5, -1.5). CONCLUSION: There was only limited evidence that changes in sleep duration or quality modified exercise-induced changes in weight, ghrelin or leptin. Moreover, the observed differences were not in the directions hypothesized. Future longitudinal studies including population-based samples using objective measures of sleep and long follow-up may help to clarify these relationships.

Interleukin-8 production by THP-1 cells stimulated by Salmonella enterica serovar Typhimurium porins is mediated by AP-1, NF-kappaB and MAPK pathways.

Interleukin-8 (IL-8) is released in response to inflammatory stimuli, such as bacterial products. Either porins or lipopolysaccharide (LPS) stimulated THP-1 cells to release IL-8 after 24 h. We have previously reported that stimulation of monocytic cells with Salmonella enterica serovar Typhimurium porins led to the activation of mitogen-activated protein kinase cascades and of protein tyrosine kinases (PTKs). In this report, we demonstrate, using two potent and selective inhibitors of MEK activation by Raf-1 (PD-098059) and p38 (SB-203580), that both ERK1/2 and p38 pathways play a key role in the production of IL-8 by porins and LPS. Porin-stimulated expression of activating protein 1 (AP-1) and correlated IL-8 release is also inhibited by PD-098059 or SB-203580 indicating that the Raf-1/MEK1-MEK2/MAPK cascade is required for their activation. Also PTKs modulate the pathway that control IL-8 gene expression, in fact its expression is abolished by tyrphostin. By using N-acetyl-leucinyl-leucinyl-norleucinal-H (ALLN) an inhibitor of nuclear factor-kappaB (NF-kappaB) activity, we also observed IL-8 release modulation. Our results elucidate some of the molecular mechanisms by which AP-1 and NF-kappaB regulate IL-8 release and open new strategies for the design of specific molecules that will modulate IL-8 effects in various infectious diseases.

Monocytic activation of protein tyrosine kinase, protein kinase A and protein kinase C induced by porins isolated from Salmonella enterica serovar Typhimurium.

OBJECTIVES: In the present study a monocytic cell line, U937, was used to investigate the possible involvement of protein tyrosine kinases (NT-PTKs), protein kinase A (PKA) and protein kinase C (PKC) in cell signaling pathways following Salmonella enterica serovar Typhimurium porin stimulation. METHODS: Different concentrations of porins and lipopolysaccharide (LPS) were analysed to evaluate changes in PTK activity by a non radioactive tyrosine kinase assay and in PKA and PKC phosphorylation by Western blotting analysis. The inhibitors of PTK, PKA and PKC activation used, were: 3,4-dihydroxybenzylidene-malononitrile (tyrphostin 23), inhibitor of epidermal growth factor (EGF) receptor tyrosine kinase activity; dihychloride (H-89), a selective inhibitor of PKA which is useful to discriminate between the effects of PKC and PKA; diacylglycerol kinase inhibitor II (R59949), which is useful for elucidating roles of PKC; calphostin C, a specific inhibitor of PKC. RESULTS: Porins of the outer membrane of the ST were isolated to be used as a stimulus in the performed experiments. Following porin treatment, a dose-dependent increase in PTK, PKA and PKC activation was observed. U937 monocytes pretreated with inhibitors induced an evident decrease in PTK activity and PKA and PKC phosphorylation pattern in porin stimulated monocytes. CONCLUSIONS: Our data support the important role played by NT-PTK, PKA and PKC in transducing the activating signal in macrophages stimulated with porins through the activation of the mitogen-activated protein kinase (MAPK) pathway that participate in the regulation of gene expression.