Regulation of complement C3 synthesis by interleukin-1 and transforming growth factor-β in rat non-transformed intestinal epithelial cell line,IEC-6

Intestinal epithelial cells are an important source of many biologically active molecules that modulate immune responses in the mucosa. The purpose of this study was to demonstrate the synthesis of complement C3 component in the rat non-transformed crypt-like intestinal epithelial cell line, IEC-6. Unstimulated IEC-6 cells secreted a low level of C3 protein and showed weak expression of C3 mRNA. The addition of interleukin (IL)-1β induced a dose- and time-dependent increase in C3 production. These effects of IL-1β were observed at a concentration as low as 0.01 ng/ml and reached a plateau at a concentration of 5 ng/ml. The effects were observed at the mRNA level as early as 6 h after the beginning of incubation. Transforming growth factor (TGF)-β alone had no effect. However, TGF-β at low concentrations (0.001–1 ng/ml) enhanced the effect of IL-1β in increasing C3 production; this enhancement was not observed at high concentrations (5–10 ng/ml). These effects of TGF-β were also observed at the mRNA level. The present findings indicate that intestinal epithelial cells are indeed capable of synthesizing complement C3 in response to IL-1β and TGF-β.     

Regulation of expression of cytokines and growth factors in osteoarthritic cartilage explants

Osteoarthritis (OA) is a degenerative joint disease characterised by the breakdown of the extracellular matrix of chondrocytes in the affected joints. Cytokines and growth factors which are known to play a role in the synthesis and degradation of cartilage matrix have been shown to be upregulated in osteoarthritic cartilage. This upregulation resulted in two different phenotypes, overexpressing either TNF-α and IL-6 or IL-1β, TGFβ₁, IL-4 and IL-10. To investigate the hierarchy among growth factors and cytokines involved in cartilage metabolism, we analysed osteoarthritic cartilage explants for their responses to human recombinant (rh) cytokines and growth factors. The cytokine expression patterns of the explants before and after in vitro culture were compared by immunohistological staining of cartilage sections. We found a coordinate expression of TNF-α and IL-6 on the one hand, and of IL-1β, TGFβ₁, IL-4 and IL-10 on the other. Although TNF-α and IL-6 stimulated each other’s expression, they downregulated TGF β₁, IL-4 and IL-10 or IL-1β, TGF β₁ and IFNg, respectively. IL-1β upregulated the expression of TGF β₁, IL-4 and IL-10, and jointly these four cytokines and growth factors downregulated IL-6. Both of the expression patterns described for OA cartilage can be explained by these regulatory mechanisms. Interestingly, no cytokine efficiently downregulated TNF-α, and even though IL-1β is upregulated in one of the OA phenotypes, none of the growth factors and cytokines tested – except for IL-1β itself – seemed capable of mediating this upregulation. This unresponsiveness to cytokine stimulation might hint at a genetic cause for the elevated expression in the respective phenotypes. Received: 15 September 2000 / Accepted: 17 April 2001     

Serum levels of tumor necrosis factor alpha,interleukin-1 alpha and beta in healthy elderly subjects

To determine the age-related changes in monokine secretion, the serum concentrations of tumor necrosis factor alpha (TNF), interleukin-1 alpha (IL-1α) and interleukin-1 beta (IL-1β) were measured in 31 young healthy subjects (21–35 years old) and 19 healthy elderly subjects (65–83 years old). There were no differences between the two groups with respect to serum concentrations of these cytokines. We also measured in a subgroup of young (n=8–11) and elderly (n=8–10) subjects the in vitro secretion of TNF and IL-1β in response to adding to the medium lipopolysaccharide (LPS, 2 ng/ml), interferon gamma (50 U/ml) or advanced glycosylation endproduct of bovine serum albumin (250 ug/ml). Only LPS-stimulated IL-1β production was significantly reduced in elderly subjects (456.7 ± 229.9 vs 1118.8 ± 494.8 pg/ml). It is concluded that with the possible exception of LPS-stimulated IL-1β production, monokine secretion measured in this study is well preserved in elderly subjects.     

Interleukin-1β inhibition of insulin release in rat pancreatic islets: Possible involvement of G-proteins in the signal transduction pathway

Summary In vitro exposure of rat pancreatic beta cells to interleukin-1β (IL-1β) inhibits glucose-stimulated insulin release (2140 ± 239 and 323 ± 80 pg · islet^–1· h^–1 at glucose levels of 16.7 mmol/l in control and IL-1β-exposed islets, respectively, n = 7, p < 0.001). Cholera toxin (2 μg/ml) or pertussis toxin (0.5 μg/ml) potentiated, as expected, glucose-induced insulin release in control islets, but, in addition, when added together with IL-1β, were able to prevent the IL-1β mediated inhibition of glucose-stimulated insulin secretion (2087 ± 301 and 1662 ± 173 pg · islet^–1· h^–1, respectively, p < 0.05 vs islets exposed to IL-1β alone). To investigate the mechanism by which the toxins prevent the IL-1β effect, we then measured nitrite levels, glucose oxidation and Ca^{2 + uptake. Nitrite levels in the culture medium were 4.2}± 1.4 and 24.0 ± 5 pmol · islet^–1· 24 h^–1 in control islets and in IL-1β-exposed islets, respectively (n = 6, p = 0.05). In islets exposed to IL-1β and cholera or pertussis toxins, nitrite levels were 9.1 ± 3 and 12.4 ± 6 pmol · islet^–1· 24 h^–1, respectively (n = 6, NS vs control islets). Glucose oxidation at 16.7 mmol/l glucose was 31.1 ± 2.9 pmol · islet^–1· 120 min^–1 in control islets and 16.8 ± 2.7 pmol · islet^–1· 120 min^–1 in IL-1β-treated islets (p < 0.05). The addition of cholera or pertussis toxins simultaneously to IL-1β prevented the inhibition of glucose oxidation at 16.7 mmol/l glucose (32.9 ± 3.8 and 31.7 ± 3.3 pmol · islet^–1· 120 min^–1 in the presence of cholera or pertussis toxins, respectively). Glucose-stimulated ⁴⁵Ca^{2 + up-take was also significantly inhibited in IL-1}β-treat-ed islets when compared to control islets (7.1 ± 0.9 and 16.8 ± 3.2 pmol · islet^–1· 20 min^–1, respectively, p < 0.05). This inhibition was prevented by the presence of cholera or pertussis toxins (14.0 ± 3.8 and 11.2 ± 2.7 pmol · islet^–1· 20 min^–1, respectively). In conclusion, our data show that cholera and, to a lesser extent, pertussis toxins are able to partially prevent the IL-1β-induced increase in nitrite levels and block the inhibitory effects of IL-1β on different steps leading to glucose-induced insulin secretion. These findings support the possibility that in pancreatic beta cells, G-proteins may be involved or interfere with the cytokine signal transduction. [Diabetologia (1995) 38: 779–784] Received: 20 October 1994 and in revised form: 5 January 1995     

Leptin upregulates beta3-integrin expression and interleukin-1beta, upregulates leptin and leptin receptor expression in human endometrial epithelial cell cultures

Human endometrium and endometrial epithelial cells (EECs) either cultured alone or cocultured with human embryos express leptin and leptin receptor. This study compares the effect of leptin with that of interleukin-1β (IL-1β) on the expression of β3-EEC integrin, a marker of endometrial receptivity. Both cytokines increased the expression of β3-EEC at concentrations in the range of 0.06–3 nM; however, leptin exhibited a significantly greater effect than IL-1β. We also determined the regulatory effects of IL-1β on leptin secretion and on the expression of leptin and leptin receptor at the protein level in both EEC and endometrial stromal cell (ESC) cultures. In EEC cultures, IL-1β upregulated secretion of leptin and expression of both leptin and leptin receptors. No effect of IL-1β was found in the ESC cultures. However, leptin exhibited marginal upregulation of leptin receptor. The upregulation of β3-integrin and leptin/leptin receptor expression by IL-1β in EEC cultures indicates that both cytokines may be implicated in embryonic-maternal cross-talk during the early phase of human implantation. Our present data also raise the possibility that leptin is an endometrial molecular effector of IL-1β action on β3-integrin upregulation. Thus, a new role for leptin in human reproduction as an autocrine/paracrine regulator of endometrial receptivity is proposed.     

Serum levels of interleukin-1β, luteinizing hormone, and prolactin correlate with the expression of CD45 isoforms on CD4+ peripheral blood T lymphocytes in healthy women

 The expected association between age and the CD45 isoforms expression on CD4+ T-PBL is much more obvious in men than in women. We investigated whether or not circulating factors influence the differentiation of CD4+ T-PBL. Peripheral blood samples were obtained from 56 healthy age-matched subjects (28 men and 28 women, 21–55 years old). Mononuclear leukocytes were analyzed by three-color flow cytometry. The serum concentrations of interleukin-1β (IL-1β), interleukin-6, tumor necrosis factor-α (TNF-α), GM colony-stimulating factor, prolactin (Prl), and luteinizing hormone (LH) were determined by ELISA. The expected age-related decrease of naive (CD45RA+,RO–) cells and increase of memory (CD45RA–,RO+) cells among CD4+ T-PBL were observed in men only (p<0.001 and 0.005). In women, these correlations were not significant. On the other hand, in women only, elevated IL-1β was associated with fewer naive and more memory cells among CD4+ T-PBL (p<0.001). In both sexes, IL-1β correlated with the expression of CD25 on CD4+ T-PBL (on either naive or memory cells, p<0.001). Other cytokines or the CD8+ T-PBL showed no significant correlation. In women, the elevation of LH at mid-cycle inversely correlated with the proportion of naive CD4+ T-PBL (p<0.01). Elevated LH was associated with more CD25 on memory CD4+ T-PBL (p<0.01). A significant correlation exists between IL-1β and LH (p<0.001). Furthermore, in both sexes, Prl correlated with the proportion of CD4+ cells among T-PBL. In men, elevated Prl was associated with more naive CD4+ T-PBL (p<0.005), while in women, Prl correlated with more transient CD45RA+, RO+ cells among CD4+ T-PBL and increased TNF-α (p<0.05 for both). Thus, circulating IL-1β could be involved in the expression of CD25 on CD4+ T-PBL and favors the generation of memory CD4+ T-PBL. In women, the IL-1β- and/or mid-cycle-dependent processes seem to overwhelm the age-related changes. Elevated Prl might exert a dual influence: it favors the development of naive CD4+ T lymphocytes and possibly acts in, synergy with other cytokines during immune stimulation. Received: 20 June 1997 / Accepted: 1 August 1997     

Annexin 1 (lipocortin 1) mimics inhibitory effects of glucocorticoids on testosterone secretion and enhances effects of interleukin-1beta

Annexin 1 is an important mediator of glucocorticoid action in the hypothalamo-pituitary axis; however, little is known of its role in mediating glucocorticoid actions in the peripheral endocrine organs. Accordingly, we have carried out a preliminary study to investigate the effects of annexin 1 in vitro on the testicular secretion of testosterone, a process inhibitied by both glucocorticoids and interleukin-1β (IL-1β). Luteinizing hormone (LH) and forskolin stimulated the release of testosterone from dispersed murine testicular cells in vitro. Their effects were reduced in cells from mice pretreated with dexamethasone (DEX). Similarly, preincubation of testicular cells from untreated mice with DEX, corticosterone, or 11-dehydrocorticosterone reduced LH-stimulated testosterone release, as did the 11β-hydroxysteroid dehydrogenase inhibitors, glycyrrhetinic acid and carbenoxolone. The inhibitory actions of the steroids were mimicked by annexin 1_1–188 (ANXA1_1–188) (a stable annexin 1 analog). IL-1β produced a marked decrease in the response to LH, which was blocked by indomethacin, a nonselective cyclooxygenase inhibitor and an additive effect with DEX and ANXA1_1–188. These results confirm reports that glucocorticoids and IL-1β inhibit LH-stimulated testosterone release from mouse testicular cells. They also show, for the first time, that the effects of the steroids are mimicked by annexin 1 and that, in contrast to their mutually antagonistic effects in the neuroendocrine system, IL-1β and annexin 1 exert additive actions in the testis.     

Differential effect of IL-1β and TNF-α on the production of IL-6, IL-8 and PGE2 in fibroblast-like synoviocytes and THP-1 macrophages

Inflammation in the joint of rheumatoid arthritis is a complex immune reaction facilitated by various factors, such as cytokines, cells and hypoxia. Thus, we evaluated their relative capacity to produce proinflammatory mediators in response to IL-1β, TNF-α or IL-17 under hypoxia or normoxia in fibroblast-like synoviocytes (FLSs) and macrophages. The level of IL-6 expression was strongly increased in both FLSs and THP-1 macrophages in response to IL-1β and TNF-α, but the level by TNF-α was less than that by IL-1β. In contrast, the expression of IL-8 in both cell types was strongly stimulated by both IL-1β and TNF-α. In FLSs, PGE₂ production increased only in response to IL-1β; and no effect was observed in THP-1 cells and TNF-α-stimulated FLSs. In addition, the production by IL-17 was extremely low when compared with those induced by IL-1β or TNF-α in FLSs and THP-1 cells. Hypoxia (2% O₂) decreased IL-1β-stimulated production of PGE₂, even though it increased the expression of mRNA and protein of COX-2. These results suggest that IL-1β and TNF-α differentially regulate gene expression in FLSs and macrophages under hypoxia or normoxia.     

IL-1β-induced pro-apoptotic signalling is facilitated by NCAM/FGF receptor signalling and inhibited by the C3d ligand in the INS-1E rat beta cell line

Aims/hypothesis IL-1β released from immune cells induces beta cell pro-apoptotic signalling via mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB). In neurons, the neural cell adhesion molecule (NCAM) signals to several elements involved in IL-1β-induced pro-apoptotic signalling in beta cells. Pancreatic beta cells express NCAM, but its biological effects in these cells are unclear. The aim of this study was to investigate whether there is cross-talk between NCAM signalling and cytokine-induced pro-apoptotic signalling.Materials and methods Western blotting was used to investigate levels of NCAM and inducible nitric oxide synthase, phosphorylation of Src and MAPKs, and cleavage of caspase-3. MAPK activity was investigated with an in vitro kinase assay. Apoptosis was detected by cleaved caspase-3 and a Cell Death Detection ELISA^plus assay. NCAM-induced fibroblast growth factor receptor (FGFR) activation was investigated in NCAM^−/− Trex293 cells where FGFR phosphorylation was measured by Western blotting after NCAM transfection.Results Pre-exposure of INS-1E cells to the FGFR-inhibitor SU5402, but not to the Src-inhibitor PP2, dose-dependently inhibited IL-1β-mediated MAPK activity. A synthetic peptide, C3d, reported to bind NCAM, did not activate MAPK or Akt as reported in neurons but inhibited IL-1β-induced MAPK activity, thereby mimicking the effect of SU5402. Furthermore, C3d inhibited NCAM-induced FGFR phosphorylation and apoptosis induced by IL-1β plus IFN-γ, but did not affect IL-1β-induced NF-κB signalling.Conclusions/interpretation We suggest that NCAM signalling through FGFR is required for efficient IL-1β pro-apoptotic signalling by facilitating IL-1β-induced MAPK activation downstream of the NF-κB-MAPK branching point. Further, these data identify a novel function of C3d as an inhibitor of NCAM-induced FGFR activity and of IL-1β-induced MAPK activation in beta cells.     

Regulation of insulin signalling, glucose uptake and metabolism in rat skeletal muscle cells upon prolonged exposure to resistin

Aims/hypothesis Debate exists regarding the role of resistin in the pathophysiology of insulin resistance. The aim of this study was to directly assess the effects of resistin (0–24 h) on basal and insulin-stimulated glucose uptake and metabolism in skeletal muscle cells and to investigate the mechanisms responsible for the effects of resistin. Methods We used L6 rat skeletal muscle cells and examined [³H]2-deoxyglucose uptake, GLUT4 translocation and GLUT protein content. We assessed glucose metabolism by measuring the incorporation of D-[U-¹⁴C]glucose into glycogen, ¹⁴CO² and lactate production, as well as the phosphorylation level and total protein content of insulin signalling proteins, including insulin receptor β-subunit (IRβ), insulin receptor substrate (IRS), Akt and glycogen synthase kinase-3β (GSK-3β). Results Treatment of L6 rat skeletal muscle cells with recombinant resistin (50 nmol/l, 0–24 h) reduced levels of basal and insulin-stimulated 2-deoxyglucose uptake and decreased insulin-stimulated GLUT4myc content at the cell surface, with no alteration in the production of GLUT4 or GLUT1. Resistin also decreased glycogen synthesis and GSK-3β phosphorylation. Insulin-stimulated oxidation of glucose via the Krebs cycle was reduced by resistin, whereas lactate production was unaltered. Although insulin receptor protein level and phosphorylation were unaltered by resistin, production of IRS-1, but not IRS-2, was downregulated and a decreased tyrosine phosphorylation of IRS-1 was detected. Reduced phosphorylation of Akt on T308 and S473 was observed, while total Akt and Akt1, but not Akt2 or Akt3, production was decreased. Conclusions/interpretation Our data show that resistin regulates the function of IRS-1 and Akt1 and decreases GLUT4 translocation and glucose uptake in response to insulin. Selective decreases in insulin-stimulated glucose metabolism via oxidation and conversion to glycogen were also induced by resistin. These observations highlight the potential role of resistin in the pathophysiology of type 2 diabetes in obesity.     

Effects of aging and menopause on serum interleukin-6 levels and peripheral blood mononuclear cell cytokine production in healthy nonobese women

Inappropriate interleukin-6 production is thought to play a role in the development of several age-related conditions including atherosclerosis. This study aimed to determine whether aging affects circulating interleukin-6 (IL-6) levels. Healthy, nonobese women (n = 208, 44.5 ± 0.70 years, 22.4 ± 0.17 kg/m²) were categorized into four age groups (22–31, 32–41, 42–51, and 52–63 years; cross-sectional study). Cytokine levels in serum and those produced from peripheral blood mononuclear cell (PBMC) were measured. The oldest group had the highest circulating levels of IL-6 and oxidized low-density lipoprotein (ox-LDL) and higher PBMC production of IL-6, tumor necrosis factor-α (TNF-α), and interleukin-1 alpha (IL-1β). Additionally, significant interactions between age and menopause were found for serum IL-6 (P = 0.024), and TNF-α (P = 0.011) and IL-1β (P < 0.001) produced from PBMCs. Serum IL-6 levels positively correlated with age, waist–hip ratio (WHR), systolic blood pressure, circulating levels of TNF-α, IL-1β, and ox-LDL, and urinary 8-epi-prostaglandin F₂α. Multiple stepwise regression models identified the following factors for contributing to serum IL-6 levels: serum IL-1β, menopause status, WHR, and serum TNF-α in mode I (R ² = 0.302); serum IL-1β, age, serum TNF-α, and WHR (β = 0.197; P = 0.006) in model II (R ² = 0.283). Sub-analysis was performed according to menopausal status. Serum IL-6 levels were positively associated with levels of IL-6, TNF-α, and IL-1β in PBMC supernatants (unstimulated) from postmenopausal women, whereas these were negatively associated in premenopausal women. In conclusion, circulating IL-6 levels may be interactively influenced by age and menopause. Additionally, estrogen deprivation after menopause may enhance PBMC cytokine production in postmenopausal women, resulting in increased IL-6 levels which are closely related to oxidative stress.     

Association between interleukin-1β-511C/T polymorphism and reflux esophagitis in Japan

Background Interleukin-1β (IL-1β) gene polymorphisms are related to hypochlorhydria and increase the risk of gastric cancer in the presence of Helicobacter pylori infection. However, little information is available about the genetic risk factors of reflux esophagitis. In this study we investigated its association with the IL-1β polymorphisms. Methods We examined 48 patients with reflux esophagitis and 96 control subjects, 89 with gastric cancer. IL-1β-511C/T genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results The frequency of IL-1β-511T alleles was significantly higher in reflux esophagitis patients (57.3%) than in controls (41.1%) (P = 0.0215, χ² = 5.289). The frequency of IL-1β-511T/T genotypes was also significantly higher in reflux esophagitis patients (31.3%) than in controls (15.6%). The odds ratio and the 95% confidence interval were 4.000 and 1.393–11.486, respectively. The frequency of IL-1β-511T/T genotypes was significantly higher in reflux esophagitis patients (31.3%) than in gastric cancer patients (21.4%). The odds ratio and the 95% confidence interval were 2.961 and 1.054–8.316, respectively. Conclusions IL-1β-511T was associated with reflux esophagitis having hyperacidity. Differences of genetic background regarding gastric acid secretion may exist between Japanese and Caucasians.     

Inflammatory Cytokines Stimulate the Adhesion of Colon Carcinoma Cells to Mesothelial Monolayers

Surgical handling of the peritoneum causes an inflammatory reaction, during which a potentially lethal cocktail of active mediators is produced, including cytokines and growth factors. The aim of this study was to investigate the effects of inflammatory cytokines on the interaction between tumor and mesothelial cells. Tumor cell adhesion to a mesothelial monolayer was assessed after preincubation of the mesothelium with interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. Preincubation of the mesothelial monolayer with IL-1β or TNF-α resulted in enhanced tumor cell adhesion of Caco2 and HT29 colon carcinoma cells. The amount of stimulation for the Caco2 cells was between 20% and 40% and for HT29 cells between 30% and 70%. Blocking experiments with anti–IL-1β and anti–TNF-α resulted in significant inhibition of the cytokine-stimulated tumor cell adhesion. The presented results prove that IL-1β and TNF-α are significant stimulating factors in tumor cell adhesion in vitro and may therefore account for tumor recurrence to the peritoneum in vivo.     

Glycoxidation of low–density lipoprotein promotes multiple apoptotic pathways and NFkB activation in human coronary cells

Apoptosis of arterial cells induced by oxidized low–density lipoprotein (oxLDL) is thought to contribute to the progression of vascular dysfunction and atherogenesis. It is well established that diabetes mellitus is accompanied by both glycosylation and oxidation LDL, but the biological effects of these modified lipoproteins are poorly understood. We demonstrate here that glycosylated oxLDL (glc–oxLDL) promotes apoptotic signaling in human coronary smooth muscle cells. This was associated by a decrease of the antiapoptotic protein Bcl–2, an increase of the pro–apoptotic protein Bax, and activation of caspase 3. Glc–oxLDL also activated NFkB and decreased IkB, these effects were more pronounced than those achieved with oxLDL. Our study shows that glc–oxLDL influences a broad cascade of signaling transduction pathways, which may not only result in apoptosis, but also could affect NFkB in human coronary cells. This cascade of events may influence the evolution of atherogenesis and vascular complications in diabetic patients.     

Vascular endothelial growth factor is upregulated by interleukin-1β in human vascular smooth muscle cells via the P38 mitogen-activated protein kinase pathway

Small tumor vessels are composed of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). These cells have been shown to communicate with each other via cytokine signaling during neovascularization. We previously demonstrated that interleukin-1β (IL-1β) leads to induction of vascular endothelial growth factor (VEGF) in human colon carcinoma cells. As pericytes play a role in regulating EC function, we hypothesized that IL-1β may mediate EC survival by induction of VEGF in a paracrine manner. We investigated the effects of IL-1β on VEGF expression in human VSMCs (hVSMCs) and the signal transduction pathways that may be involved. Treatment of hVSMCs with IL-1β induced VEGF expression in a time- and concentration-dependent manner and increased both the VEGF promoter activity and the mRNA half-life. Treatment with IL-1β induced the expression of P38 mitogen-activated protein kinase (MAPK) within 5 min but did not activate extracellular signal-regulated kinases (Erk)-1/2, c-jun amino terminal kinase (JNK), or Akt. SB203580, a specific P38 MAPK inhibitor, blocked the ability of IL-1β to induce VEGF mRNA and promoter activity. Conditioned media from hVSMCs pretreated with IL-1β prevented apoptosis of ECs, an effect that was partially abrogated by VEGF-neutralizing antibodies. These data demonstrate that IL-1β may induce VEGF in hVSMCs, and suggest that this paracrine signaling pathway, may prevent, in part, apoptosis of ECs. This revised version was published online in June 2006 with corrections to the Cover Date.     

KSHV LANA inhibits TGF-beta signaling through epigenetic silencing of the TGF-beta type II receptor

Signaling through the transforming growth factor–β (TGF-β) pathway results in growth inhibition and induction of apoptosis in various cell types. We show that this pathway is blocked in Kaposi sarcoma herpesvirus (KSHV)–infected primary effusion lymphoma through down-regulation of the TGF-β type II receptor (TβRII) by epigenetic mechanisms. Our data also suggest that KSHV infection may result in lower expression of TβRII in Kaposi sarcoma and multicentric Castleman disease. KSHV-encoded LANA associates with the promoter of TβRII and leads to its methylation and to the deacetylation of proximal histones. Reestablishment of signaling through this pathway reduces viability of these cells, inferring that KSHV-mediated blockage of TGF-β signaling plays a role in the establishment and progression of KSHV-associated neoplasia. These data suggest a mechanism whereby KSHV evades both the antiproliferative effects of TGF-β signaling by silencing TβRII gene expression and immune recognition by suppressing TGF-β–responsive immune cells through the elevated secretion of TGF-β1.     

Cows' milk proteins cause similar Th1- and Th2-like immune response in diabetic and healthy children

Aims/hypothesis: Cows' milk proteins have been proposed to play a part in the pathogenesis of Type I (insulin-dependent) diabetes mellitus but both epidemiological and immunological studies have given conflicting results. Thus we aimed to study the immunological response to cows' milk proteins among diabetic and healthy children, focusing on the balance of Th1- and Th2-like lymphocytes. Methods: Peripheral blood mononuclear cells from 30 Type I diabetic children (4 to 18 years old) were examined and compared with peripheral blood mononuclear cells from 18 healthy age-matched control children (7 to 15 years old). Expression of IFN-γ and IL-4 mRNA were detected by realtime RT-PCR and as protein by ELISA after stimulation with BSA, the ABBOS-peptide (a. a. 152–169) and β-lactoglobulin (βLG) from cows' milk and ovalbumin from hens' egg. Phytohaemagglutinin and keyhole limpet haemocyanin were used as positive and negative controls, respectively. Results: Bovine serum albumin caused a weak Th2-like response in Type I diabetic children, whereas BSA antibodies decreased with age only among healthy children. Otherwise, cows' milk proteins (BSA, ABBOS and βLG) caused increased expression for IFN-γ and IL-4 mRNA in diabetic and healthy children. βLG caused the strongest immunological response, which decreased with age only among diabetic children. However, ovalbumin from egg caused a similar activation of the immune system and the immune response was similar in both diabetic and healthy children. Conclusion/interpretation: Proteins from cows' milk caused an equal Th1- and Th2-like immune response in diabetic and healthy children. Thus, our results do not support the hypothesis that cows' milk antigens are important for the immune process associated with Type I diabetes. [Diabetologia (2001) 44: 1140–1147] Received: 6 February 2001 and in revised form: 14 May 2001     

Identification of IL-1β-induced messenger RNAs in rat pancreatic beta cells by differential display of messenger RNA

Abstract Aims/hypothesis. Interleukin-1β is a putative mediator of pancreatic beta-cell dysfunction and damage in Type I (insulin-dependent) diabetes mellitus. To better understand the molecular mechanisms involved in IL-1β effects, we carried out a differential display of mRNA by RT-PCR to identify novel cytokine-regulated genes. Methods. Fluorescence activated cell sorting-purified rat pancreatic beta-cells were exposed for 6 or 24 h to IL-1β. Differentially expressed cDNA bands were cloned and then identified by comparing their sequences with data from the GenBank. Differential gene expression was confirmed by RT-PCR using specific primers. Results. Interleukin-1β increased the expression of adenine nucleotide translocator-1, phospholipase D-1 and cytokine-induced neutrophil chemoattractant-1 and decreased expression of the protein tyrosine phosphatase-like protein IA-2. Interleukin-1β-induced differential expression of these genes in beta cells was confirmed by RT-PCR. In additional studies, IL-1β was shown to induce chemokines other than cytokine-induced neutrophil chemoattractant-1, including cytokine-induced neutrophil chemoattractant-3 and monocyte chemotactic protein-1. Conclusion/interpretation. Our observations indicate that IL-1β modifies the expression of several genes in pancreatic beta cells. These genes may affect both function, viability and beta-cell recognition by the immune system. Functional characterization of the mRNAs which have been identified could facilitate a better understanding of the mechanisms leading to beta-cell destruction in Type I diabetes. [Diabetologia (1999) 42: 1199–1203] Received: 4 June 1999 and in revised form: 1 July 1999