Transcriptional profiling reliably discriminates between PBCs from SSc and normal donors despite the fact that they represent a heterogeneous cell population. Multiple biological pathways were differentially regulated in SSc PBCs, but a common thread across these pathways was alterations in protein tyrosine kinase 2beta and mitogen-activated protein kinase signalling. Although the SSc PBC gene expression profile demonstrated some parallels with the lupus interferon gene signature, there was also increased expression of transcripts encoding proteins that target PBCs to the endothelium, which might be relevant to the vasculopathy of SSc.

Photodetectors fabricated on microstructured silicon are reported. The photodetectors exhibited high photoresponse; at 3V bias, the responsivities were 92A∕W at 850nm and 119A∕W at 960nm. At wavelengths longer than 1.1μm, the photodetectors still showed strong photoresponse. A generation-recombination gain mechanism has been proposed to explain the photoresponse of these photodiodes. From measurements of the noise current density, the calculated gain was approximately 1200 at 3V bias.

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IntroductionSPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs.MethodsIn in vitro studies, skin fibroblasts obtained from a Tgfbr1 knock-in mouse (TBR1CA; Cre-ER) were transfected with SPARC siRNA. Gene and protein expressions of the Col1a2 and the Ctgf were examined by real-time RT-PCR and Western blotting, respectively. In in vivo studies, C57BL/6 mice were induced for skin and lung fibrosis by bleomycin and followed by SPARC siRNA treatment through subcutaneous injection and intratracheal instillation, respectively. The pathological changes of skin and lungs were assessed by hematoxylin and eosin and Masson's trichrome stains. The expression changes of collagen in the tissues were assessed by real-time RT-PCR and non-crosslinked fibrillar collagen content assays.ResultsSPARC siRNA significantly reduced gene and protein expression of collagen type 1 in fibroblasts obtained from the TBR1CA; Cre-ER mouse that was induced for constitutively active TGF-β receptor I. Skin and lung fibrosis induced by bleomycin was markedly reduced by treatment with SPARC siRNA. The anti-fibrotic effect of SPARC siRNA in vivo was accompanied by an inhibition of Ctgf expression in these same tissues.ConclusionsSpecific inhibition of SPARC effectively reduced fibrotic changes in vitro and in vivo. SPARC inhibition may represent a potential therapeutic approach to fibrotic diseases.

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Fibroblasts from patients with systemic sclerosis (SSc) are activated producing excessive amounts of extracellular matrix (ECM) components. Recently, we identified a new SSc-specific autoantibody against portions of fibrillin-1, a major component of ECM microfibrils and regulator of TGF-β1 signaling. To examine a potential pathogenic role of anti-fibrillin-1 autoantibodies, normal human fibroblasts were treated with affinity-purified autoantibodies isolated from SSc sera and then examined for alterations in gene and protein expression levels using microarrays, quantitative RT-PCR, immunoblots, and immunofluorescence. Compared with fibroblasts cultured in normal medium or in medium containing normal human IgG, anti-fibrillin-1 autoantibody-treated normal dermal fibroblasts showed increased expression of COL and several other ECM components characteristically overexpressed in SSc fibroblasts. This was accompanied by phosphorylation and nuclear translocation of Smad3. Neutralization of TGF-β1 with anti-TGF-β1 Abs significantly diminished the activation of fibroblasts by anti-fibrillin-1 autoantibodies. These data indicate that anti-fibrillin-1 autoantibodies can induce the activation of normal dermal fibroblasts into a profibrotic phenotype resembling that of SSc by potentially causing the release of sequestered TGF-β1 from fibrillin-1-containing microfibrils in the ECM.

Objective. Recently, it was observed that SPARC (secreted protein, acidic and rich in cysteine) is overexpressed in the fibroblasts of skin biopsy specimens obtained from patients with systemic sclerosis (SSc; scleroderma), and that specific inhibition of SPARC expression in normal human fibroblasts attenuated the profibrotic effect of transforming growth factor ␤ (TGF␤). The purpose of this study was to examine whether inhibition of SPARC with small interfering RNA (siRNA) can be used to ameliorate the overproduction of major extracellular matrix components in SSc fibroblasts.Methods. Fibroblasts obtained from biopsy specimens of the unaffected skin of 3 patients with diffuse SSc and 3 age-and sex-matched healthy controls were cultured and transfected with SPARC siRNA. Before and after transfection, real-time quantitative reverse transcription-polymerase chain reaction, immunostaining, and Western blotting were used to examine the transcription and/or protein levels of SPARC, connective tissue growth factor (CTGF), type I collagen, type II collagen, TGF␤ receptor 1 (TGF␤R1), and Smad3.Student's paired t-tests were used to determine the significance of the results.Results. SSc fibroblasts showed overexpression of SPARC, COL1A2, COL3A1, and CTGF, which is consistent with an activated fibroblast phenotype. Upon inhibition of SPARC with siRNA, these activated SSc fibroblasts showed decreased gene expression of COL1A2, COL3A1, and CTGF (43%, 54%, and 58%, respectively). In addition, the overproduction of type I collagen protein in SSc fibroblasts was inhibited and was shown to parallel levels of SPARC expression. In contrast, the expression of TGFBR1 and Smad3 did not change significantly nor was the level of phosphorylation of Smad3 reduced upon SPARC siRNA silencing in unstimulated cultured SSc fibroblasts.Conclusion. Overproduction of collagens in SSc skin fibroblasts can be attenuated through SPARC silencing. This inhibition may be associated either with direct interaction between SPARC and collagens or with inhibition of CTGF, which is a downstream effector of TGF␤ signaling. However, SPARC silencing in SSc fibroblasts appears not to be associated with TGFBR1-and Smad3-dependent processes. Application of SPARC silencing represents a potential therapeutic approach to SSc.

Frequent somatic mutations of BRAF (v-raf murine sarcoma viral oncogene homolog B) exon T1799A, which are implicated in the initial events of promutagenic cellular proliferation, are detected in both malignant melanomas (MM) and melanocytic nevi (MN). Most of the data regarding BRAF exon T1799A mutation have been from Caucasian cohorts, and a comprehensive screening of a homogeneous population is lacking. A total of 379 cases of MN and 195 cases of MM were collected from Chinese Han living in three geographical regions in China, i.e., northeast, southwest, and northwest China. BRAF exon T1799A mutation was detected by PCR and sequencing from microdissected tumors. In all, 59.8% cases of MN harbored BRAF exon T1799A mutation. Samples from regions with high UV exposure had higher detection rates than regions with lower UV exposure (73.5, 67.0, and 38.9%, respectively; χ(2) = 31.674, P = 1.59E-7). There were no differences in mutation rates between congenital and acquired MN; however, acquired MN with advanced age of onset had a higher mutation rate than those with younger age of onset (χ(2) = 13.23, P = 0.02). In all, 15.0% cases of MM harbored the BRAF mutation. The mutation rate in MM was not affected by region, histological type, gender, pattern of UV exposure, and age. The study suggests that the mutation is not necessarily associated with malignant transformation.