The intracellular molecular events involved in the ␤-cell death process are complex but poorly understood. Cytokines, e.g., interleukin (IL)-1␤, may play a crucial role in inducing this process. Protein synthesis is necessary for the deleterious effect of IL-1, and induction of both protective and deleterious proteins has been described. To characterize the rather complex pattern of islet protein expression in rat islets in response to IL-1, we have attempted to identify proteins of altered expression level after IL-1 exposure by 2D gel electrophoresis and mass spectrometry. Of 105 significantly changed (i.e., up-or downregulated or de novo-induced) protein spots, we obtained positive protein identification for 60 protein spots. The 60 identifications corresponded to 57 different proteins. Of these, 10 proteins were present in two to four spots, suggesting that posttranslatory modifications had occurred. In addition, 11 spots contained more than one protein. The proteins could be classified according to their function into the following groups: 1) energy transduction; 2) glycolytic pathway; 3) protein synthesis, chaperones, and protein folding; and 4) signal transduction, regulation, differentiation, and apoptosis. In conclusion, valuable information about the molecular mechanisms involved in cytokine-mediated ␤-cell destruction was obtained by this approach. Protein synthesis inhibitors (e.g., cycloheximide) effectively protect IL-1-exposed islets from destruction (12). Hence, protein synthesis is necessary for the deleterious effect of IL-1. Previous studies have shown that IL-1 induces the synthesis of members of the heat shock protein (HSP) family, like heme oxygenase (13) and HSPs 70 and 90 (14,15), and hyperexpression of HSPs in islets is partially protective against cytokine-induced ␤-cell destruction (16). Furthermore, it has been reported that IL-1 may induce the synthesis of unknown proteins with molecular weights of 45,50, 75, 85, 95, and 120 kDa (17). It has previously been shown that rat islets exposed to IL-1 release NO into the culture media (18). iNOS has been cloned from islets (19) in which it has been shown to be inducible in ␤-cells only (20). We have further shown that IL-1 also upregulates IL-1 converting enzyme mRNA transcription (21) in rat islets. Also, SOD is shown to be upregulated in islets by cytokines (15,22).Based on ␤-cell-selective toxic effects, we hypothesized that IL-1 induces a rather complex pattern of both protective and deleterious events and mechanisms in islets cells, and that in ␤-cells the deleterious events seem to prevail (23). We further suggested that this might be reflected at the level of islet protein expression (24). To examine this hypothesis, we used 2D gel electrophoresis to produce a database of rat islet proteins containing about 2,200 protein spots characterized by molecular weight and isoelectric point (pI). The data presented here provide the first global assessment of the IL-1-mediated ␤-cell-damaging processes at the protein level. We could demonstra...

The IL-17 family of cytokines consists of at least six members (IL-17A to -F). IL-17 directly activates epithelial cells leading to the expression of inflammatory mediators and antimicrobial factors. Recent studies showed that IL-17C is expressed by epithelial cells. It was the purpose of this study to examine the expression of IL-17 family members in respiratory epithelial cells during bacterial infection. We show that common bacterial pathogens, such as Pseudomonas aeruginosa and Haemophilus influenzae, and ligands of Toll-like receptors 3 and 5 (flagellin, polyI:C) induced the expression and release of IL-17C in cultured human bronchial epithelial cells (HBECs). The expression of IL-17A, -B, -D, or -E was not induced by bacterial stimuli in HBECs. IL-17C enhanced inflammatory responses of respiratory epithelial cells infected with P. aeruginosa. Furthermore, we demonstrate that cigarette smoke suppressed the expression of IL-17C in HBECs in response to bacterial infection and in vivo in the upper airways of mice colonized with H. influenzae. IL-17C could also be detected in bronchial tissue of subjects with infection-related lung diseases. These data show that IL-17C is involved in the innate immune response of respiratory epithelial cells and is suppressed by cigarette smoke.

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Smoking is the most important risk factor for both lung cancer (LC) and chronic obstructive pulmonary disease. The aim of this study was to investigate the role of myeloid cell nuclear factor-κB in the regulation of tumor cell growth signaling. We subjected mice lacking myeloid RelA/p65 (rela(Δ-/-)) to a metastatic LC model. Cigarette smoke (CS) exposure significantly increased the proliferation of Lewis lung carcinoma cell tumors in wild-type mice. In CS-exposed rela(Δ-/-) mice, the tumor growth was largely inhibited. Transcriptome and pathway analysis of cancer tissue revealed a fundamental impact of myeloid cells on various growth signaling pathways, including the Wnt/β-catenin pathway. In conclusion, myeloid RelA/p65 is necessary to link smoke-induced inflammation with LC growth and has a role in the activation of Wnt/β-catenin signaling in tumor cells.

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