Conserved structural motifs in intracellular trafficking pathways: structure of the gammaCOP appendage domain

The formation of coated vesicles is a fundamental step in many intracellular trafficking pathways. COPI and clathrin represent two important and distinct sets of vesicle coating machinery, involved primarily in mediating intra-Golgi and endocytic transport, respectively. Here we identify an important functional region at the carboxyl terminus of the gamma subunit of the COPI complex (gammaCOP) and describe the X-ray crystal structure of this domain at 2.3 A resolution. This domain of gammaCOP exhibits unexpected structural similarity to the carboxyl-terminal appendage domains of the alpha and beta subunits of the AP2 adaptor proteins, integral components of clathrin-coated vesicles. The remarkable structural conservation exhibited by the gammaCOP appendage domain, coupled with functional data and primary sequence analysis, supports a model of COPI function with significant structural and mechanistic parallels to vesicular transport by the clathrin/AP2 system.     

MicroRNA Profiling in Prostate Cancer - The Diagnostic Potential of Urinary miR-205 and miR-214

Prostate cancer (PCa) is the most common type of cancer in men in the United States, which disproportionately affects African American descents. While metastasis is the most common cause of death among PCa patients, no specific markers have been assigned to severity and ethnic biasness of the disease. MicroRNAs represent a promising new class of biomarkers owing to their inherent stability and resilience. In the present study, we investigated potential miRNAs that can be used as biomarkers and/or therapeutic targets and can provide insight into the severity and ethnic biasness of PCa. PCR array was performed in FFPE PCa tissues (5 Caucasian American and 5 African American) and selected differentially expressed miRNAs were validated by qRT-PCR, in 40 (15 CA and 25 AA) paired PCa and adjacent normal tissues. Significantly deregulated miRNAs were also analyzed in urine samples to explore their potential as non-invasive biomarker for PCa. Out of 8 miRNAs selected for validation from PCR array data, miR-205 (p<0.0001), mir-214 (p<0.0001), miR-221(p<0.001) and miR-99b (p<0.0001) were significantly downregulated in PCa tissues. ROC curve shows that all four miRNAs successfully discriminated between PCa and adjacent normal tissues. MiR-99b showed significant down regulation (p<0.01) in AA PCa tissues as compared to CA PCa tissues and might be related to the aggressiveness associated with AA population. In urine, miR-205 (p<0.05) and miR-214 (p<0.05) were significantly downregulated in PCa patients and can discriminate PCa patients from healthy individuals with 89% sensitivity and 80% specificity. In conclusion, present study showed that miR-205 and miR-214 are downregulated in PCa and may serve as potential non-invasive molecular biomarker for PCa.     

Transthyretin immunoreactivity in human and porcine liver, choroid plexus, and pancreatic islets

We examined transthyretin immunoreactivity (TTR-IR) in human and porcine liver, choroid plexus, and pancreatic islets with both polyclonal and monoclonal antibodies to TTR. The specificity of the immunoreactions and the effects of various fixatives were tested in immunohistochemical and dot-blot systems. B-5 fixative (mercuric chloride and sodium acetate in formalin) was the best immunopreservative. In both species, the TTR-IR in choroid plexus epithelial cells was strong and was much greater than that in hepatocytes. Glucagon cells in pancreatic islets were also strongly TTR immunoreactive. Insulin cells were slightly TTR immunoreactive in human but strongly so in porcine pancreas. The finding of TTR-IR in normal islets explains the presence of TTR-IR in human endocrine pancreatic tumors, notably glucagonomas and malignant insulinomas.     

An analysis of the sensitivity of somatic cell hybrids to natural killer cell- and natural cytotoxic cell-mediated lysis

The analysis of the NK and NC sensitivity of somatic cell hybrids formed between parental cell lines that differ in their NK and NC sensitivity has shown the following. 1) The dominant expression of both NK and NC recognition determinants on target cells; 2) the dominant expression of two post-recognitive NC resistance mechanisms, one requiring protein synthesis and one being protein synthesis independent; and 3) the dominant expression of a post-recognitive NK resistance mechanism, which is protein synthesis independent. The post-recognitive protein synthesis-independent NC resistance mechanism confers no NK resistance and the post-recognitive NK resistance mechanism confers no NC resistance. Whether the post-recognitive protein synthesis-dependent NC resistance mechanism confers NK resistance remains open to question. The analysis of the hybrids indicates that transformed cells become sensitive to either NK- or NC-mediated lysis by losing their resistance to the lytic activity of these effector cells, and it appears that differentiation plays a role in determining whether NK or NC resistance will be lost upon transformation. A model is proposed in which the differentiation into a fibroblast associates the loss of NC resistance with transformation, whereas the differentiation into a lymphocyte associates the loss of NK resistance with transformation. Because the loss of NK resistance is not associated with the transformation of fibroblasts, they remain NK resistant, and because the transformation of lymphocytes is not associated with the loss of NC resistance, they remain NC resistant. This provides the basis for the target specificity exhibited by NK and NC effectors.     

Molecular genetics of the transcription factor GLIS3 identifies its dual function in beta cells and neurons

The GLIS family zinc finger 3 isoform (GLIS3) is a risk gene for Type 1 and Type 2 diabetes, glaucoma and Alzheimer's disease endophenotype. We identified GLIS3 binding sites in insulin secreting cells (INS1) (FDR q < 0.05; enrichment range 1.40–9.11 fold) sharing the motif wrGTTCCCArTAGs, which were enriched in genes involved in neuronal function and autophagy and in risk genes for metabolic and neuro-behavioural diseases. We confirmed experimentally Glis3-mediated regulation of the expression of genes involved in autophagy and neuron function in INS1 and neuronal PC12 cells. Naturally-occurring coding polymorphisms in Glis3 in the Goto-Kakizaki rat model of type 2 diabetes were associated with increased insulin production in vitro and in vivo, suggestive alteration of autophagy in PC12 and INS1 and abnormal neurogenesis in hippocampus neurons. Our results support biological pleiotropy of GLIS3 in pathologies affecting β-cells and neurons and underline the existence of trans?nosology pathways in diabetes and its co-morbidities.     

Fibreoptic bronchoscopy: ten years on.

Fibreoptic bronchoscopy was introduced more than 10 years ago and is now in many centres a routine diagnostic procedure, having superseded rigid bronchoscopy. Its major role is in the diagnosis of bronchial carcinoma, where the results are as good as, if not better than, results with the rigid instrument. Other major applications have been found in investigating haemoptysis, transbronchial lung biopsy in interstitial lung disease, and in the critically ill patient in the intensive care unit. More recently, the instrument has been used to perform bronchoalveolar lavage in investigating interstitial lung diseases and to enable lobar and segmental lung function studies to be performed. Fibreoptic bronchoscopy is a major advance in the diagnosis of pulmonary diseases, but there will always be times when rigid bronchoscopy is preferable.     

Health service accreditation: report of a pilot programme for community hospitals.

Voluntary accreditation in the United Kingdom is being used by health care providers to improve and market their services and by commissioners to define and monitor service contracts. In a three year pilot scheme in the south west of England, 43 out of 57 eligible community hospitals volunteered to be surveyed; 37 of them were ultimately accredited for up to two years by the hospital accreditation programme. The main causes for non-accreditation related to safety, clinical records, and medical organisation. Follow up visits in 10 hospitals showed that, overall, 69% of recommendations were implemented. An independent survey of participating hospitals showed the perceived benefits to include team building, review of operational policies, improvement of data systems, and the generation of local prestige. Purchasers are increasingly influenced by accreditation status but are mostly unwilling to finance the process directly. None the less, the concept may become an important factor moderating the quality of service in the new NHS.