No description available.

Asmall gene family may be involved in sorting proteins to rafts and hence transport to intracellular organelles and the plasma membrane.  MAL is found to localise to lipid rafts and is involved in the sorting of apical proteins in polarised epithelial cell types.  BENE and Plasmolipin have also been associated with lipid rafts in either endothelial or glial cells.  However, MAL, BENE and Plasmolipin are not expressed in endocrine tissues.  Recently, a human EST of partial sequence was proposed to be the fourth member of this family.  During the current study, the complete coding sequence of this member, termed MAL2, was identified in rat <span lang=EN-US style='font-family:Symbol'>b-cells of the pancreas.  Furthermore, through library screening and 5’ RACE, two isoforms of MAL2 were identified - rMAL2-A and rMAL2-B.  The two isoforms differ at their amino termini and rMAL2-B contains a long 5’ UTR with upstream AUG (uAUG) codons and two open reading frames.  Analysis of these uAUG codons found they were capable of decreasing expression of a reporter gene construct and likely to contribute to the observed low expression of rMAL2-B.  Both isoforms were found to be glycosylated on the second extracellular/intralumenal loop.  rMAL2-A and rMAL2-B appeared not to display raft association within <span lang=EN-US style='font-family:Symbol'>b-cells, although further work is required to refine the extraction procedure.  Subcellular analysis of the two isoforms found that they mainly localised to the Golgi, overlapping in distribution with TGN38, an endogenous TGN marker.

No description available.

Long-term exposure to diabetes mellitus is associated with metabolic abnormalities such as chronic hyperglycemia and redox imbalance. Uncontrolled hyperglycaemia and genetic factors are implicated in the pathogenesis of diabetic microvascular diseases. Genetic mutation through the genes coding for enzymes involved in glucose metabolism and immuno-regulatory mechanisms may contribute to the susceptibility to type I diabetes mellitus (TIDM) and its chronic microvascular diseases. Previous studies have shown that the transcription factor, nuclear factor kappa 8 (NFκB) and heat shock proteins (HSPs) are two redox-sensitive cellular responses of most immune and inflammatory diseases including diabetes and its late vascular complications. NFκB promotes the transcription of a wide array of proinflammatory mediators and adhesion molecules. HSPs are proposed to have a cytoprotective effect; in contrast they have the capacity to promote pathogenic processes. In this study, polymerase chain reaction (PCR)-based microsatellite analysis and restriction fragment length polymorphism (RFLP) analysis were used to genotype the genes coding for NFκB, HSP70-A2, sorbitol dehydrogenase (SORD) and protein kinase C- β(PKC-β). The A10 allele of the NFκB gene and H3 and H7 alleles of the HSP70-A2 gene were identified as risk markers of TIDM (P< 0.01). These alleles were not associated with microvascular complications. No evidence of associations was obtained between either PKC-β or SORD genes with TIDM and its late complications. Uncontrolled hyperglycaemia may alter the transcription mechanism of many genes, which control vascular homeostasis. The electrophoresis mobility shift assay (EMSA) was used to assess the transcription factor, heat shock factor-1 (HSF-1) and NFκB-DNA binding activity in response to a concentration of 31 mM D- glucose in peripheral blood mononuclear cells (PBMCs) from patients with TIDM with and without microvascular complications. Hyperglycaemia induced significant increases in both NFκB and HSF-1-DNA binding activities in PBMCs from patients (p= 0.003 and 0.017 respectively). The protein activity was more pronounced in PBMCs from patients with microvascular complications. Hyperglycaemia-induced NFκB-DNA binding activity was correlated to that of HSF-1 (p< 0.0 I). Patients with TIDM with microvascular complications demonstrated a significant increase in NFκB-DNA binding activity compared to patients with a short duration of diabetes (SD) or diabetic controls (DC) (p= 0.003 and p = 0.047 respectively). A significant positive correlation was found between the duration of diabetes and hyperglycaemia-induced NFκB-DNA binding activity (p=0.035). These results suggest that hyperactive flux through the polyol pathway is relevant to hyperglycaemia-induced protein activity since the aldose reductase inhibitors (ARIs) zopolrestat and sorbinil reduced HSF-1 and NFκB-DNA binding activity in PBMCs. In conclusion, these results suggest that NFκB and HSP70-A2 genes may contribute to the genetic susceptibility to TIDM. Uncontrolled hyperglycaemia in diabetes may alter the transcription mechanism and magnify the proinflammatory responses, which accelerate the development of diabetic microvascular complications.

No description available.

No description available.

This thesis describes the development and evaluation of two self-management interventions for patients with type 2 diabetes. The first (the UCL-DSMP) was a theoretically based group intervention, targeting the behavioural and psychosocial demands of diabetes. The second, which was not formally evaluated due to poor uptake, additionally included social support skills training and required attendance with a partner. Development included a systematic review of previous interventions including analysis of component efficacy, focus groups with health care professionals and patients, and piloting of the interventions. For each intervention a manual specifying content and facilitation techniques was produced. The UCL-DSMP was compared to standard treatment in individuals with type 2 diabetes and microalbuminuria or proteinuria. Participants (n=124) completed assessments preintervention, immediately post-intervention (IPI) and at 3 and 9 month follow-ups. The UCL-DSMP significantly improved diet (p 0.001), exercise (p 0.001), and blood glucose monitoring (p 0.001) at IPI relative to controls. Results were retained for exercise and blood glucose monitoring at both 3 and 9 months follow-up (p 0.05). Diabetes specific quality of life was better in the intervention group relative to controls at all follow-ups (p 0.05). There were no differences on generic quality of life or psychological wellbeing. Knowledge was improved by the intervention (p 0.001) as was behaviour specific self- efficacy (p 0.05), which was identified as a significant mediator of change in exercise (p 0.05) and blood glucose monitoring (p 0.05) at 3 and 9 months respectively. Illness beliefs, specifically belief in treatment effectiveness (p 0.01) and control (p 0.05) improved following the intervention at IPI, however results were not retained in the longer term and beliefs were not significant mediators of behaviour change. No clear or consistent predictors of efficacy were identified. These findings suggest the UCL-DSMP may be a useful intervention for patients with type 2 diabetes. Areas for further development and recommendations for clinical practice are discussed.

The aryl-hydrocarbon receptor (AhR) is an important receptor found in immune cells. It functions as a detector of environmental toxins, naturally occurring dietary products, and endogenous tryptophan derivatives for induction of gene transcription responses. Previous reports have implicated stimulation of AhR by various ligands in promoting T cell activation or regulatory function, with effects on autoimmune disease models. Also, effects of Ah toxins or natural products on increasing or suppressing inflammation and innate cytokine production, and dendritic cell function, have been reported. Different AhR-ligands could help in the development of either regulatory or pro-inflammatory T cells and consequently affect autoimmunity. In the present study, the effects of specific AhR-ligands on CD4 T cells, BMDC and CD8 T cells were investigated. Their effects were also tested for the first time on the induction of autoimmune diabetes using two different mouse models. Co-injection of the AhR-ligands curcumin, quercetin, or the ligand precursor tryptophan with sub-diabetogenic multiple low dose streptozotocin (MLD-STZ), increased the incidence of hyper-glycemia in C57Bl/6J mice. Furthermore, these ligands were able to significantly increase the development of Th17 and Th1 subsets and suppress Treg cells, in vivo and in vitro. In contrast, other ligands, including FICZ and I3C, decreased the incidence of diabetes in the MLD-STZ mouse model, in addition to their ability to increase the development of Th17, Th1 and Treg subsets, in vivo and in vitro. We found that injecting gp130fl/flCD4-Cre+ mice, which are characterized by enhanced production of Treg and reduced Th17 cell development, with MLD-STZ failed to cause hyper-glycemia, suggesting that the IL-6-receptor pathway controlling the Th17/Treg cell balance is important for diabetes induced by MLD-STZ. The effect of tryptophan, curcumin or quercetin was also tested for the first time using the RIP-LCMV-GP / P14 TCR transgenic diabetes model. We find that co-injection of these ligands together with immunisation with mature bone marrow-derived dendritic cells (BMDC) carrying self-antigen increased the incidence of diabetes in RIP-GP/P14 TCR transgenic mice. Also, these AhR-ligands were able to significantly increase Tc17 and Tc1 cell subsets, in vitro and in vivo. Furthermore, these ligands were able to increase the secretion of both pro-inflammatory, anti-inflammatory cytokines, and the expression of IDO by BMDC. FICZ and I3C, however, increased the expression of IDO and the anti-inflammatory cytokines TGF-β and IL-10. An immuno-suppressive function of FICZ and I3C was confirmed by co-injection of these AhR-ligands together with immunisation with mature BMDC carrying self-antigen, which resulted in a decrease in the incidence of diabetes in RIP-GP/P14 TCR transgenic mice. Suppression of diabetes was associated with increased development of IL-10+ CD8+ T cells, in vitro, while having no significant effect on either Tc1 or Tc17 subsets. It is concluded from this study that, the AhR-ligands FICZ and I3C could be attractive compounds to be used as therapeutics for diabetes and other autoimmune diseases, due to their ability to increase regulatory T cells (Treg and IL-10+ CD8+ ) subsets and enhance the secretion of anti-inflammatory cytokines and IDO expression by BMDC. However, activation of the AhR pathway by other AhR-ligands is associated with increased Th1/Tc1 and Th17/Tc17 responses, which could worsen autoimmunity.

No description available.

No description available.