A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins

CD59 is a glycosylphosphatidylinositol (GPI)-anchored cell surface inhibitor of the complement membrane attack complex (MAC). We showed previously that CD59 is highly expressed in pancreatic islets but is down-regulated in rodent models of diabetes. CD59 knockdown but not enzymatic removal of cell surface CD59 led to a loss of glucose-stimulated insulin secretion (GSIS), suggesting that an intracellular pool of CD59 is required. In this current paper, we now report that non-GPI-anchored CD59 is present in the cytoplasm, colocalizes with exocytotic protein vesicle-associated membrane protein 2, and completely rescues GSIS in cells lacking endogenous CD59 expression. The involvement of cytosolic non-GPI-anchored CD59 in GSIS is supported in phosphatidylinositol glycan class A knockout GPI anchor-deficient β-cells, in which GSIS is still CD59 dependent. Furthermore, site-directed mutagenesis demonstrated different structural requirements of CD59 for its 2 functions, MAC inhibition and GSIS. Our results suggest that CD59 is retrotranslocated from the endoplasmic reticulum to the cytosol, a process mediated by recognition of trimmed N-linked oligosaccharides, supported by the partial glycosylation of non-GPI-anchored cytosolic CD59 as well as the failure of N-linked glycosylation site mutant CD59 to reach the cytosol or rescue GSIS. This study thus proposes the previously undescribed existence of non-GPI-anchored cytosolic CD59, which is required for insulin secretion.-Golec, E., Rosberg, R., Zhang, E., Renström, E., Blom, A. M., King, B. C. A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins.

Complement Component C3 Is Highly Expressed in Human Pancreatic Islets and Prevents β Cell Death via ATG16L1 Interaction and Autophagy Regulation

We show here that human pancreatic islets highly express C3, which is both secreted and present in the cytosol. Within isolated human islets, C3 expression correlates with type 2 diabetes (T2D) donor status, HbA1c, and inflammation. Islet C3 expression is also upregulated in several rodent diabetes models. C3 interacts with ATG16L1, which is essential for autophagy. Autophagy relieves cellular stresses faced by β cells during T2D and maintains cellular homeostasis. C3 knockout in clonal β cells impaired autophagy and led to increased apoptosis after exposure of cells to palmitic acid and IAPP. In the absence of C3, autophagosomes do not undergo fusion with lysosomes. Thus, C3 may be upregulated in islets during T2D as a cytoprotective factor against β cell dysfunction caused by impaired autophagy. Therefore, we revealed a previously undescribed intracellular function for C3, connecting the complement system directly to autophagy, with a broad potential importance in other diseases and cell types.

The Noncoding RNA nc886 Regulates PKR Signaling and Cytokine Production in Human Cells

Protein kinase RNA-activated (PKR) is a cytoplasmic receptor for dsRNA, and as such is involved in detection of viral infection. On binding dsRNA, PKR dimerizes, autophosphorylates, and then phosphorylates its substrate, eukaryotic translation initiation factor 2 subunit α (eIF2α), causing inhibition of mRNA translation and shutdown of viral protein production. However, active PKR has also been found to be involved in the NF-κB signaling pathway by inducing phosphorylation of IκBα. PKR is regulated by the noncoding RNA nc886, which has altered expression in cancer. We have found that expression of nc886 is highly upregulated during activation of human CD4⁺ T cells. As has been described in other cell types, nc886 bound to PKR in human T cell lysates, preventing PKR phosphorylation by polyinosinic:polycytidylic acid or HIV trans-activation response element RNA in lysates of T cell lines or primary human CD4⁺ T cells. Using clonal human T cell lines, we found that nc886 expression was strictly required for IFN-γ and IL-2 expression and secretion after T cell activation but did not affect proliferation or activation-induced cell death. In stimulated human PBMCs, nc886 expression strongly correlated with IFN-γ expression. Although nc886 inhibited PKR activation by dsRNA, it was required for PKR phosphorylation during T cell stimulation, with subsequent NF-κB signaling and CREB phosphorylation. nc886 also regulated PKR phosphorylation during human monocyte-derived macrophage activation. We have therefore identified nc886 as a noncoding RNA marker of T cell activation and regulator of PKR-dependent signaling.

CD46 Activation Regulates miR-150-Mediated Control of GLUT1 Expression and Cytokine Secretion in Human CD4+ T Cells

CD46 is a cell surface complement inhibitor widely expressed in human tissues, in contrast to mice, where expression is limited to the testes. In humans, it has been identified as an important T cell costimulatory receptor, and patients deficient in CD46 or its endogenous ligands are unable to mount effective Th1 T cell responses. Stimulation of human CD4(+) T cells with CD3 and CD46 also leads to the differentiation of a "switched" Th1 population, which shuts down IFN-γ secretion and upregulates IL-10 and is thought to be important for negative feedback regulation of the Th1 response. In the present study, we show that CD46 costimulation leads to amplified microRNA (miR) expression changes in human CD4(+) T cells, with associated increases in activation more potent than those mediated by the "classic" costimulator CD28. Blockade of cell surface CD46 inhibited CD28-mediated costimulation, identifying autocrine CD46 signaling as downstream of CD28. We also identify a downregulation of miR-150 in CD46-costimulated T cells and identify the glucose transporter 1 encoding transcript SLC2A1 as a target of miR-150 regulation, connecting miR-150 with modulation of glucose uptake. We also investigated microRNA expression profiles of CD46-induced switched IL-10-secreting Th1 T cells and found increased expression of miR-150, compared with IFN-γ-secreting Th1 cells. Knockdown of miR-150 led to a reduction in IL-10 but not IFN-γ. CD46 therefore controls both Th1 activation and regulation via a miR-150-dependent mechanism.

Genetic profiling of yeast industrial strains using in situ comparative genomic hybridization (CGH)

The genetic differences and changes in genomic stability may affect fermentation processes involving baker's, brewer's and wine yeast strains. Thus, it seems worthwhile to monitor the changes in genomic DNA copy number of industrial strains. In the present study, we developed an in situ comparative genomic hybridization (CGH) to investigate the ploidy and genetic differences between selected industrial yeast strains. The CGH-based system was validated using the laboratory Saccharomyces cerevisiae yeast strains (haploid BY4741 and diploid BY4743). DNA isolated from BY4743 cells was considered a reference DNA. The ploidy and DNA gains and losses of baker's, brewer's and wine strains were revealed. Taken together, the in situ CGH was shown a helpful molecular tool to identify genomic differences between yeast industrial strains. Moreover, the in situ CGH-based system may be used at the single-cell level of analysis to supplement array-based techniques and high-throughput analyses at the population scale.

Single-cell analysis of aneuploidy events using yeast whole chromosome painting probes (WCPPs)

Aneuploidy is considered a widespread genetic variation in such cell populations as yeast strains, cell lines and cancer cells, and spontaneous changes in the chromosomal copy number may have implications for data interpretation. Thus, aneuploidy monitoring is essential during routine laboratory practice, especially while conducting biochemical and/or gene expression analyses. In the present study, we constructed a panel of whole chromosome painting probes (WCPPs) to monitor aneuploidy in a single yeast Saccharomyces cerevisiae cell. The WCPP-based system was validated using "normal" haploid and diploid cells, as well as disomic cells both with and without cell synchronisation. FISH that utilised WCPPs was combined with DNA cell cycle analysis (imaging cytometry) to provide a detailed analysis of signal variability during the cell cycle. Chromosome painting can be utilised to detect spontaneously formed disomic chromosomes and study aneuploidy-promoting conditions. For example, the frequency of disomic chromosomes was increased in cells lacking NAD(+)-dependent histone deacetylase Sir2p compared with wild-type cells (p<0.05). In conclusion, WCPPs may be considered to be a powerful molecular tool to identify individual genomic differences. Moreover, the WCPP-based system may be used at the single-cell level of analysis to supplement array-based techniques and high-throughput analyses at the population scale.

[Antero-lateral impingement syndrome and evaluation of chronic post-traumatic instability in the talo-crural joint]

The aim of this paper was to asses whether the antero-lateral impingement syndrome is a sequel of ligamentous-capsular element failure in the talo-crural joint. The authors evaluated stability of the talocrural joint on a stand by one of the authors (E. G.). Using Zwipp's method and the authors own method the kind and degree of instability were assessed. Radiological features of antero-lateral instability were found in 17 patients (4.6%)--7 female (1.9%) and 10 male patients (2.7%) aged from 25 to 54 years. 4 grade II antero-lateral instabilities 2 grade III lateral instabilities and 1 grade V instability concomitant to antero-lateral impingement were found in the female patients. Whereas among the male patients 6 grade II antero-lateral instabilities and 4 grade III instabilities were found.

[Intramedullary Gamma nail fixation in the treatment of peritrochanteric fractures]

The paper presents the authors' own experience in the treatment of periotrochanteric fractures. A clinical survey from 1998 to 2001 was carried out on 26 patients aged 21-72. The number of women was 20 (77%) and of men 6 (23%). This paper is an preliminary report.

The significance of selected epidemiologico-clinical factors in the prevalence of the Helicobacter pylori infection in young males

A serological diagnosis (ELISA test) was carried out of infections by Helicobacter pylori in 1200 young males (recruits in the Polish Army) and the influence of selected epidemiologico-clinical factors (civil status, place of residence, profession, economical conditions, tobacco smoking, consumption of alcohol, diseases of the parodontonium, nutritional habits) on the prevalence of the infection was studied. Specific antibodies were detected in 228 (19%) of the persons tested. Of the eight factors analyzed, only three parodontium diseases, tobacco smoking and place of residence (of decreasing importance in that order), had a statistically significant relationship to infection by Helicobacter pylori in young males.

The relationship between the frequency of the appearance of IgG against Helicobacter pylori and the main blood groups among patients with ulcer sickness and stomach cancer

Among the 763 patients with ulcers and stomach cancer, including the control group of 586 blood donors, the search for a relationship between the spread of infection and the main blood groups was defined by the appearance of IgG against H. pylori in blood plasma (the ELISA test). The statistical analysis, however, did not prove that the frequency of the appearance of specific antibodies against H. pylori was statistically important in relation to the ABO blood groups.

[Syringomyelia--is it only a problem in neurosurgery?]

Three cases of arthroplasty in the course of syringomyelia are presented. These patients have been diagnosed in orthopedic-traumatologic department due to their bony/articular symptoms. After having established the diagnosis the patients were referred to Neurosurgery. Final diagnosis of syringomyelia requires computerized tomography and magnetic resonance imaging. Syringomyelia necessitates an early surgical treatment.