State Library Update, April 2004

Quarterly State Library Update for patrons.

Neutrophils activate plasmacytoid dendritic cells by releasing self-DNA-peptide complexes in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a severe and incurable autoimmune disease characterized by chronic activation of plasmacytoid dendritic cells (pDCs) and production of autoantibodies against nuclear self-antigens by hyperreactive B cells. Neutrophils are also implicated in disease pathogenesis; however, the mechanisms involved are unknown. Here, we identified in the sera of SLE patients immunogenic complexes composed of neutrophil-derived antimicrobial peptides and self-DNA. These complexes were produced by activated neutrophils in the form of web-like structures known as neutrophil extracellular traps (NETs) and efficiently triggered innate pDC activation via Toll-like receptor 9 (TLR9). SLE patients were found to develop autoantibodies to both the self-DNA and antimicrobial peptides in NETs, indicating that these complexes could also serve as autoantigens to trigger B cell activation. Circulating neutrophils from SLE patients released more NETs than those from healthy donors; this was further stimulated by the antimicrobial autoantibodies, suggesting a mechanism for the chronic release of immunogenic complexes in SLE. Our data establish a link between neutrophils, pDC activation, and autoimmunity in SLE, providing new potential targets for the treatment of this devastating disease.

A peptide inhibitor of c-Jun N-terminal kinase for the treatment of endotoxin-induced uveitis.

PURPOSE: To evaluate the effect of XG-102 (formerly D-JNKI1), a TAT-coupled dextrogyre peptide that selectively inhibits the c-Jun N-terminal kinase, in the treatment of endotoxin-induced uveitis (EIU). METHODS: EIU was induced in Lewis rats by LPS injection. XG-102 was administered at the time of LPS challenge. The ocular biodistribution of XG-102 was evaluated using immunodetection at 24 hours after either 20 microg/kg IV (IV) or 0.2 microg/injection intravitreous (IVT) administrations in healthy or uveitic eyes. The effect of XG-102 on EIU was evaluated using clinical scoring, infiltration cell quantification, inducible nitric oxide synthase (iNOS) expression and immunohistochemistry, and cytokines and chemokines kinetics at 6, 24, and 48 hours using multiplex analysis on ocular media. Control EIU eyes received vehicle injection IV or IVT. The effect of XG-102 on c-Jun phosphorylation in EIU was evaluated by Western blot in eye tissues. RESULTS: After IVT injection, XG-102 was internalized in epithelial cells from iris/ciliary body and retina and in glial and microglial cells in both healthy and uveitic eyes. After IV injection, XG-102 was concentrated primarily in inflammatory cells of uveitic eyes. Using both routes of administration, XG-102 significantly inhibited clinical signs of EIU, intraocular cell infiltration, and iNOS expression together with reduced phosphorylation of c-Jun. The anti-inflammatory effect of XG-102 was mediated by iNOS, IFN-gamma, IL-2, and IL-13. CONCLUSIONS: This is the first evidence that interfering with the JNK pathway can reduce intraocular inflammation. Local administration of XG-102, a clinically evaluated peptide, may have potential for treating uveitis.

Is a Combined School/Public Library Right for Your Community?

This document is intended to assist Iowa communities in making informed decisions on combining school and public library services. It provides decision-makers with a means of assessing the feasibility of establishing a combined library and, if the decision is made to proceed, with a Planning Guide that addresses the many areas of library operations that need to be considered if the combined library is to be successful. Alternatives to combining libraries exist. Contracted services provide one such option. There are many areas where school and public libraries can and should collaborate in order to provide better service to the community. These alternatives are also outlined in this document.

Glucagon-like peptide-1 protects beta-cells against apoptosis by increasing the activity of an IGF-2/IGF-1 receptor autocrine loop.

OBJECTIVE: The gluco-incretin hormones glucagon-like peptide (GLP)-1 and gastric inhibitory peptide (GIP) protect beta-cells against cytokine-induced apoptosis. Their action is initiated by binding to specific receptors that activate the cAMP signaling pathway, but the downstream events are not fully elucidated. Here we searched for mechanisms that may underlie this protective effect. RESEARCH DESIGN AND METHODS: We performed comparative transcriptomic analysis of islets from control and GipR(-/-);Glp-1-R(-/-) mice, which have increased sensitivity to cytokine-induced apoptosis. We found that IGF-1 receptor expression was markedly reduced in the mutant islets. Because the IGF-1 receptor signaling pathway is known for its antiapoptotic effect, we explored the relationship between gluco-incretin action, IGF-1 receptor expression and signaling, and apoptosis. RESULTS: We found that GLP-1 robustly stimulated IGF-1 receptor expression and Akt phosphorylation and that increased Akt phosphorylation was dependent on IGF-1 but not insulin receptor expression. We demonstrated that GLP-1-induced Akt phosphorylation required active secretion, indicating the presence of an autocrine activation mechanism; we showed that activation of IGF-1 receptor signaling was dependent on the secretion of IGF-2. We demonstrated, both in MIN6 cell line and primary beta-cells, that reducing IGF-1 receptor or IGF-2 expression or neutralizing secreted IGF-2 suppressed GLP-1-induced protection against apoptosis. CONCLUSIONS: An IGF-2/IGF-1 receptor autocrine loop operates in beta-cells. GLP-1 increases its activity by augmenting IGF-1 receptor expression and by stimulating secretion; this mechanism is required for GLP-1-induced protection against apoptosis. These findings may lead to novel ways of preventing beta-cell loss in the pathogenesis of diabetes.

Desensitization and phosphorylation of the glucagon-like peptide-1 (GLP-1) receptor by GLP-1 and 4-phorbol 12-myristate 13-acetate.

Glucagon-like peptide-1 (GLP-1) stimulates glucose-induced insulin secretion by binding to a specific G protein-coupled receptor linked to activation of the adenylyl cyclase pathway. Here, using insulinoma cell lines, we studied homologous and heterologous desensitization of GLP-1-induced cAMP production. Preexposure of the cells to GLP-1 induced a decrease in GLP-1-mediated cAMP production, as assessed by a 3- to 5-fold rightward shift of the dose-response curve and an approximately 20 percent decrease in the maximal production of cAMP. Activation of protein kinase C by the phorbol ester phorbol 12-myristate 13-acetate (PMA) also induced desensitization of the GLP-1-mediated response, leading to a 6- to 9-fold shift in the EC50 and a 30% decrease in the maximal production of cAMP. Both forms of desensitization were additive, and the protein kinase C inhibitor RO-318220 inhibited PMA-induced desensitization, but not agonist-induced desensitization. GLP-1- and PMA-dependent desensitization correlated with receptor phosphorylation, and the levels of phosphorylation induced by the two agents were additive. Furthermore, PMA-induced, but not GLP-1-induced, phosphorylation was totally inhibited by RO-318220. Internalization of the GLP-1 receptor did not participate in the desensitization induced by PMA, as a mutant GLP-1 receptor lacking the last 20 amino acids of the cytoplasmic tail was found to be totally resistant to the internalization process, but was still desensitized after PMA preexposure. PMA and GLP-1 were not able to induce the phosphorylation of a receptor deletion mutant lacking the last 33 amino acids of the cytoplasmic tail, indicating that the phosphorylation sites were located within the deleted region. The cAMP production mediated by this deletion mutant was not desensitized by PMA and was only poorly desensitized by GLP-1. Together, our results indicate that the production of cAMP and, hence, the stimulation of insulin secretion induced by GLP-1 can be negatively modulated by homologous and heterologous desensitization, mechanisms that involve receptor phosphorylation.

A novel interferon-gamma regulated human melanoma-associated antigen, gp33-38, defined by monoclonal antibody Me14-D12. II. Molecular cloning of a genomic probe.

The human Me14-D12 antigen is a cell surface glycoprotein regulated by interferon-gamma (IFN-gamma) on tumor cell lines of neuroectodermal origin. It consists of two non-convalently linked subunits with apparent mol. wt sizes of 33,000 and 38,000. Here we describe the molecular cloning of a genomic probe for the Me14-D12 gene using the gene transfer approach. Mouse Ltk- cells were stably cotransfected with human genomic DNA and the Herpes Simplex virus thymidine kinase (TK) gene. Primary and secondary transfectants expressing the Me14-D12 antigen were isolated after selection in HAT medium by repeated sorting on a fluorescence activated cell sorter (FACS). A recombinant phage harboring a 14.3 kb insert of human DNA was isolated from a genomic library made from a positive secondary transfectant cell line. A specific probe derived from the phage DNA insert allowed the identification of two mRNAs of 3.5 kb and 2.2 kb in primary and secondary L cell transfectants, as well as in human melanoma cell lines expressing the Me14-D12 antigen. The regulation of Me14-D12 antigen by INF-gamma was retained in the L cell transfectants and could be detected both at the level of protein and mRNA expression.

Brain natriuretic peptide is able to stimulate cardiac progenitor cell proliferation and differentiation in murine hearts after birth.

Brain natriuretic peptide (BNP) contributes to heart formation during embryogenesis. After birth, despite a high number of studies aimed at understanding by which mechanism(s) BNP reduces myocardial ischemic injury in animal models, the actual role of this peptide in the heart remains elusive. In this study, we asked whether BNP treatment could modulate the proliferation of endogenous cardiac progenitor cells (CPCs) and/or their differentiation into cardiomyocytes. CPCs expressed the NPR-A and NPR-B receptors in neonatal and adult hearts, suggesting their ability to respond to BNP stimulation. BNP injection into neonatal and adult unmanipulated mice increased the number of newly formed cardiomyocytes (neonatal: +23 %, p = 0.009 and adult: +68 %, p = 0.0005) and the number of proliferating CPCs (neonatal: +142 %, p = 0.002 and adult: +134 %, p = 0.04). In vitro, BNP stimulated CPC proliferation via NPR-A and CPC differentiation into cardiomyocytes via NPR-B. Finally, as BNP might be used as a therapeutic agent, we injected BNP into mice undergoing myocardial infarction. In pathological conditions, BNP treatment was cardioprotective by increasing heart contractility and reducing cardiac remodelling. At the cellular level, BNP stimulates CPC proliferation in the non-infarcted area of the infarcted hearts. In the infarcted area, BNP modulates the fate of the endogenous CPCs but also of the infiltrating CD45(+) cells. These results support for the first time a key role for BNP in controlling the progenitor cell proliferation and differentiation after birth. The administration of BNP might, therefore, be a useful component of therapeutic approaches aimed at inducing heart regeneration.

State Library Update, July 2006

Quarterly State Library Update for patrons.

Soluble MHC-peptide complexes induce rapid death of CD8+ CTL.

Soluble MHC-peptide (pMHC) complexes, commonly referred to as tetramers, are widely used to enumerate and to isolate Ag-specific CD8(+) CTL. It has been noted that such complexes, as well as microsphere- or cell-associated pMHC molecules compromise the functional integrity of CTL, e.g., by inducing apoptosis of CTL, which limits their usefulness for T cell sorting or cloning. By testing well-defined soluble pMHC complexes containing linkers of different length and valence, we find that complexes comprising short linkers (i.e., short pMHC-pMHC distances), but not those containing long linkers, induce rapid death of CTL. This cell death relies on CTL activation, the coreceptor CD8 and cytoskeleton integrity, but is not dependent on death receptors (i.e., Fas, TNFR1, and TRAILR2) or caspases. Within minutes of CTL exposure to pMHC complexes, reactive oxygen species emerged and mitochondrial membrane depolarized, which is reminiscent of caspase-independent T cell death. The morphological changes induced during this rapid CTL death are characteristic of programmed necrosis and not apoptosis. Thus, soluble pMHC complexes containing long linkers are recommended to prevent T cell death, whereas those containing short linkers can be used to eliminate Ag-specific CTL.

Most residues on the floor of the antigen binding site of the class I MHC molecule H-2Kd influence peptide presentation.

A panel of 15 single alanine substitutions on the floor of the peptide binding groove of the murine class I histocompatibility molecule H-2Kd has been analyzed. All but two mutant molecules were expressed on the cell surface, and were tested for peptide binding and presentation to specific cytotoxic T lymphocytes. Eleven out of 13 mutant molecules appeared to be functionally altered. Five of the substituted residues were involved in the presentation of all peptides tested. Three participated in the presentation of certain peptides but not others. Three other residues participated in epitope formation through indirect interactions. Only two mutations had no detectable effect.

Investigation into Randolph Public Library's Closed Session Violations, December 11, 2006

Investigative report produced by Iowa Citizens' Aide/Ombudsman

Open Door Newsletter of the Library, Summer 2006

The Open Door newsletter is produced by the Iowa Commission for the Blind. It is published twice a year with information about the library programs and what is going on.

Open Door Newsletter of the Library, Winter 2003

The Open Door newsletter is produced by the Iowa Commission for the Blind. It is published twice a year with information about the library programs and what is going on.

Open Door Newsletter of the Library, Winter 2003

The Open Door newsletter is produced by the Iowa Commission for the Blind. It is published twice a year with information about the library programs and what is going on.