Elevated interferon gamma expression in the central nervous system of tumour necrosis factor receptor 1-deficient mice with experimental autoimmune encephalomyelitis

Inflammation in the central nervous system (CNS) can be studied in experimental autoimmune encephalomyelitis (EAE). The proinflammatory cytokines interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) are implicated in EAE pathogenesis. Signals through the type 1 TNF receptor (TNFR1) are required for severe EAE to develop, whereas deficiency in IFN-gamma or its receptor result in more severe EAE. We investigated IFN-gamma expression in TNFR1-deficient (TNFR1-/-) mice. We describe here that there were more IFN-gamma-secreting T cells present in the CNS of TNFR1-/- mice during EAE compared to wild-type (WT) mice, despite that clinical symptoms were mild, with delayed onset. There was greater expression of IL-12/23p40 by antigen-presenting cells in these mice, and in vitro, TNFR1-/- antigen-presenting cells induced greater secretion of IFN-gamma but not interleukin (IL)-17 when cultured with primed T cells than did WT antigen presenting cells. TNFR1-/- mice with EAE had significantly higher expression of CXCL10 mRNA (but not CCL5 mRNA) in the CNS compared to WT mice with EAE. These data demonstrate that IFN-gamma expression is enhanced in the CNS of TNFR1-/- mice with EAE and suggest that IFN-gamma levels do not necessarily correlate with EAE severity.     

Gender differences in the insulin-like growth factor axis response to a glucose load

Aims: The insulin‐like growth factors (IGFs) are thought to contribute to glucose homeostasis. The aim of our study was to examine the response of the IGFs and their binding proteins to an intravenous load of glucose in a cohort of young men and women with normal glucose tolerance. Methods: The intravenous glucose tolerance test (IVGTT) was used to quantify insulin sensitivity and insulin secretion in 160 adults aged 20–21 years in Adelaide, Australia. Serum IGF‐I, IGF‐II, IGF‐binding protein (IGFBP)‐1 and IGFBP‐3 were measured during the IVGTT. Results: Women were less insulin sensitive than men with higher fasting insulin (women 55.6 ± 4.4, men 44.1 ± 3.6 pmol L^?1, P = 0.001) and first phase insulin secretion (women 3490 ± 286, men 3038 ± 271 pmol L^?1 min, P = 0.042). Women showed lower fasting free IGF‐I (women 0.29 ± 0.02, men 0.36 ± 0.02 μg L^?1, P = 0.004) but higher IGFBP‐3 (women 46.3 ± 0.53, men 43.3 ± 0.58 mg dL^?1, P = 0.001) and higher IGFBP‐1 concentrations (women 37.0 ± 2.9, men 24.8 ± 2.3 μg L^?1, P = 0.012). IGFBP‐1 fell by 5 min and remained suppressed. IGFBP‐3 and total IGF‐I fell until 60 min rising again by 2 h. IGF and IGFBP values were all higher in women. IGFBP‐1 showed a negative association with fasting and stimulated insulin concentrations in both genders. First phase insulin secretion however showed positive correlations with IGFBP‐3 (r = 0.321, P = 0.004) and IGF‐I (r = 0.339 P = 0.002) in men but not women. Conclusion: Our data show that IGFBP‐1, IGFBP‐3 and IGF‐I show acute changes following a glucose load and there are marked gender differences in these responses.     

Second generation adeno-associated virus type 2-based gene therapy systems with the potential for preferential integration into AAVS1

Adeno-associated virus type 2 (AAV-2) is a non-pathogenic human parvovirus that is being developed as a gene therapy vector for the treatment of numerous diseases. One property of wild-type AAV-2, that is highly desirable in a gene therapy vector, is its ability to preferentially integrate its DNA into a 4 kilobase region of human chromosome 19, designated AAVS1. One disadvantage of AAV-2 is its relatively small packaging capacity, approximately 4.7 kilobases. Because of this size limitation, the AAV-2 rep and cap genes were removed from first-generation AAV-2-based gene therapy vectors to make room for the therapeutic or marker gene. It was later discovered that the rep gene, or at least one of its products, the Rep68 or Rep78 protein, is required for preferential integration of AAV-2. Recent developments in AAV-2 gene therapy vector construction allow the inclusion of the rep gene into a second generation of AAV-2-based gene therapy systems. These new systems fall into four major categories: plasmid-based systems, co-transduction with multiple AAV-2 vectors, incorporation of the AAV-2 vector into a larger virus, and in vitro packaging. These systems not only allow the inclusion of the rep gene, they also allow the delivery of larger therapeutic genes.     

Effect of maternal feed restriction on blood pressure in the adult guinea pig

Small size at birth has been associated with increased blood pressure in adult men and women. In rats, isocaloric protein restriction reduces fetal growth and increases systolic blood pressure in adult offspring. Balanced maternal undernutrition in the rat also increases adult blood pressure, but not consistently. The aim of this study was to determine the effect of moderate balanced maternal undernutrition (85% of ad libitum intake from 4 weeks before, and throughout pregnancy) on blood pressure of adult offspring in the guinea pig, a species that is relatively mature at birth. Blood pressure was measured in chronically catheterised offspring of ad libitum fed or feed-restricted mothers, at 3 months of age (young adult). Maternal feed restriction reduced birth weight (-17%) and increased systolic blood pressure (+9%, P < 0.03) in young adult male offspring. In offspring of ad libitum fed and feed-restricted mothers, combined data showed that systolic blood pressure and mean arterial pressure correlated negatively with head width at birth (P = 0.02 and P = 0.04, respectively, n = 28). Systolic blood pressure also correlated negatively with birth weight and the ratio birth weight/birth length, but only in offspring of ad libitum fed mothers (P = 0.04 and P = 0.03, respectively, n = 22). The effect of maternal feed restriction on systolic blood pressure in male offspring was not significant when adjusted for these measures of size at birth. Thus, moderate balanced undernutrition in the guinea pig increases systolic blood pressure in young adult male offspring; however, these effects may be mediated, at least in part, through effects on fetal growth.     

Improving attention control in dysphoria through cognitive training: Transfer effects on working memory capacity and filtering efficiency

Impaired filtering of irrelevant information from working memory is thought to underlie reduced working memory capacity for relevant information in dysphoria. The current study investigated whether training‐related gains in working memory performance on the adaptive dual n‐back task could result in improved inhibitory function. Efficacy of training was monitored in a change detection paradigm allowing measurement of a sustained event‐related potential asymmetry sensitive to working memory capacity and the efficient filtering of irrelevant information. Dysphoric participants in the training group showed training‐related gains in working memory that were accompanied by gains in working memory capacity and filtering efficiency compared to an active control group. Results provide important initial evidence that behavioral performance and neural function in dysphoria can be improved by facilitating greater attentional control.     

The central nervous system environment controls effector CD4+ T cell cytokine profile in experimental allergic encephalomyelitis

In experimental allergic encephalomyelitis (EAE), CD4⁺ T cells infiltrate the central nervous system (CNS). We derived CD4⁺ T cell lines from SJL/J mice that were specific for encephalitogenic myelin basic protein (MBP) peptides and produced both Th1 and Th2 cytokines. These lines transferred EAE to naive mice. Peptide-specific cells re-isolated from the CNS only produced Th1 cytokines, whereas T cells in the lymph nodes produced both Th1 and Th2 cytokines. Mononuclear cells isolated from the CNS, the majority of which were microglia, presented antigen to and stimulated MBP-specific T cell lines in vitro. Although CNS antigen-presenting cells (APC) supported increased production of interferon (IFN)-γ mRNA by these T cells, there was no increase in the interleukin (IL)-4 signal, whereas splenic APC induced increases in both IFN-γ and IL-4. mRNA for IL-12 (p40 subunit) was up-regulated in both infiltrating macrophages and resident microglia from mice with EAE. We have thus shown that a Th1 cytokine bias within the CNS can be induced by CNS APC, and that IL-12 is up-regulated in microglial cells within the CNS of mice with EAE. Microglia may therefore control Th1 cytokine responses within the CNS.     

A NOVEL ACTION OF INSULIN ON PHOSPHOPROTEIN FORMATION BY MAMMARY GLAND EXPLANTS

Studies on the induction of casein synthesis in competent daughter cells formed in mammary gland explants have revealed a new action of insulin. Treatment with prolactin, in the absence of insulin, is responsible for the formation of some polypeptides which are destined to become phosphoproteins, or for the formation of a unique protein-kinase, or both. In any case, insulin is required for participation of the prolactin-induced factor(s) in a protein-kinase reaction.