NIHRDataInsights/HRCSData huggingface dataset:
Title: Protein palmitoylation in adipocytes: role in insulin action
Funder: Diabetes UK

Abstract: S-palmitoylation, the attachment of palmitate to cysteine residues, has emerged as a prominent post-translational modification that regulates many diverse proteins and cellular pathways. Although some key proteins involved in insulin signalling are palmitoylated, the importance of cellular palmitoylation dynamics for insulin action is not defined. The aim of this studentship is to build an understanding of how palmitoylation contributes to adipocyte physiology relevant to insulin action. This will begin by mapping the expression profiles of the 23 mammalian DHHC palmitoyl transferases, and identifying expression changes that occur during adipocyte differentiation. Recently developed techniques to study palmitoylation will be employed to purify the adipocyte palmitoylome. This will be followed by a targeted screen of the purified palmitoylome to identify known components of insulin signalling/Glut4 trafficking pathways that are palmitoylated. This targeted screening will be combined with an unbiased proteomics/mass spectrometry screen to identify novel proteins that undergo insulin-dependent changes in palmitoylation status. The role of palmitoylation in regulating specific proteins relevant to insulin action, and the global impact of palmitoylation on insulin signalling, Glut4 trafficking and fatty acid transport will be investigated. The work described will deliver entirely novel information on how palmitoylation contributes to insulin action in adipocytes.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING
Health categories: METABOLIC AND ENDOCRINE
Title: Role of microRNAs in skeletal muscle insulin resistance
Funder: Diabetes UK

Abstract: Skeletal muscle insulin resistance (IR) is an essential prerequisite for the development of Type 2 Diabetes, but the molecular basis of its pathogenesis is complex and incompletely understood. Aberrant microRNA regulation of key metabolic and signalling pathways is a potential mechanism that would unify the disparate observed expression defects in muscle IR. In this project the student will investigate this possibility by addressing two objectives. Firstly he/she will study the time-course of regulation of microRNAs during the development of high fat diet-induced insulin resistance in rat muscle using specific Real time PCR analyses. The dysregulated microRNAs identified in this way will then be subjected to bioinformatic analysis in order to identify putative target metabolic and signalling genes and pathways. In vitro analysis will then be undertaken in muscle cell culture using specific microRNA inhibitors and viral overexpression in order to confirm the identity of dysregulated target pathways that mediate their effects on insulin sensitivity. This will involve both quantifying relevant mRNA and protein expression and assessing key biochemical and physiological endpoints eg. glucose disposal and fat oxidation. Thus the student will begin to establish the target pathways that may underpin a causative relationship between microRNA dysregulation and IR.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: METABOLIC AND ENDOCRINE
Title: The role of GM3, a glycosphingolipid, as a modulator of skeletal muscle insulin sensitivity
Funder: Diabetes UK

Abstract: Skeletal muscle insulin sensitivity is inversely correlated with intramyocellular accumulation of fatty acid-derived lipids such as ceramide and DAG, which impair post-receptor insulin signalling events. However, there is also mounting evidence to support an important role for plasma membrane glycosphingolipids, in particular GM3, in the pathogenesis of insulin resistance. GM3 has been suggested to associate with and negatively regulate insulin-receptor activity by promoting segregation of receptors to GM3-enriched membrane microdomains. GM3 can be synthesised from ceramide in response to saturated fatty acids (e.g. palmitate) and TNFalpha, which may also orchestrate changes in the expression of proteins regulating synthesis (GM3 synthase) and breakdown (NEU3) of GM3. Enhanced PKC/ERK/CREB signalling has been suggested to promote GM3 synthase expression in non-muscle cells, but we find that this pathway is also activated in muscle cells in response to palmitate and that this is antagonised by AMPK activators. The work described herein aims to: (i) define the signalling mechanisms regulating GM3 turnover in muscle cells in response to palmitate and TNF?, (ii) establish how GM3 promotes dysregulation of proteins involved in insulin signalling and (iii) assess whether pharmacological antagonism of glycosphingolipid metabolism enhances insulin sensitivity of cultured myotubes and skeletal muscle of obese rodents


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: METABOLIC AND ENDOCRINE
Title: Generation of human islet antigen-specific regulatory T cells for the treatment of Type 1 diabetes
Funder: Diabetes UK

Abstract: Regulatory T cells (Tregs) play a key role in controlling the expansion of pathogenic autoreactive T cells and preventing the development of autoimmunity. Studies in animal models demonstrate that strategies to increase the number or functional potency of Tregs are able to prevent or reverse the onset of type 1 diabetes (T1D), making them a logical target for intervention strategies in humans. Critically, these studies highlighted the importance of antigen specificity: islet-specific Tregs have far greater potency than those derived from polyclonal populations. This studentship aims to develop protocols to enhance both the number and functional potency of islet-specific Tregs in individuals with T1D. This will involve the ex-vivo manipulation of bulk populations of autologous Tregs isolated from individuals with T1D to endow (i) islet specificity, (ii) enhanced regulatory function and (iii) improved stability. This will be achieved by the lentiviral-mediated transfer of genes leading to the expression of (i) T cell receptor alpha and beta chains with specificity for islet antigens and (ii) stable and high levels of the Treg lineage transcription factor FoxP3. We propose that these ‘enhanced’ Tregs would represent a powerful therapeutic tool to halt and/or reverse the immune mediated destruction of beta cells that leads to T1D


Research activity codes: 5.2 CELLULAR AND GENE THERAPIES
Health categories: METABOLIC AND ENDOCRINE
Title: Understanding the relationship between sex hormones and Type 2 diabetes risk
Funder: Diabetes UK

Abstract: A huge amount of research has described the potential role of sex hormones in causing and treating diabetes and its complications. Hormones studied include testosterone, estradiol, DHEAS and the binding protein, SHBG, but it is not known if altered levels of these hormones are primary causes of diabetes, or a secondary effect of the disease process. Recent genetic evidence, contrary to most opinions, has suggested that the lower SHBG levels seen in diabetic patients could partly cause the condition. In this proposal a student working in a world class diabetes research environment will use the powerful genetic approach of Mendelian randomisation to test the hypothesis that sex hormones have an aetiological role in diabetes. First the student will use genome wide genetic data from >20,000 individuals to identify genetic variation that influences sex hormone levels. Next the student will use the latest “next generation sequencing” techniques to fully characterise the regions of the genome associated with sex hormones. In the third stage the student will validate findings in a study of 1000 type 2 diabetes patients and 1000 controls. In the fourth step the student will perform “mendelian randomization” tests of association between gene variants that influence sex hormone levels and diabetes, insulin resistance and beta cell function


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: METABOLIC AND ENDOCRINE
Title: Mechanisms of action of peptide immunotherapy for Type 1 diabetes: characterising T cells induced or modified by proinsulin C19-A3
Funder: Diabetes UK

Abstract: Current insulin replacement therapy for Type 1 diabetes does not address the underlying autoimmune pathology and patients remain at risk of complications. Antigen-specific immunotherapy using peptides from beta-cell proteins is a safe strategy that aims to reduce immune-driven beta-cell destruction, restore immune tolerance and salvage residual endogenous insulin secretion. We are conducting a randomised, double-blind, placebo-controlled trial of proinsulin peptide C19-A3 therapy. The Fellowship aims to study the immune response to C19-A3 by gene expression microarray and test the hypotheses (i) that peptide immunotherapy induces antigen-specific immune regulation and (ii) that it induces changes in immune cell repertoire. These studies are key to defining biomarkers of responsiveness that are central to the future safe and effective development of this therapy.


Research activity codes: 5.1 PHARMACEUTICALS
Health categories: METABOLIC AND ENDOCRINE
Title: The epidemiology, impact and individual assessment of low level insulin production in Type 1 diabetes
Funder: Diabetes UK

Abstract: Type 1 diabetes (T1D) is the most common form of diabetes in the young. It is caused by autoimmune destruction of insulin producing pancreatic beta cells. There is evidence that low level insulin production is beneficial in insulin treated patients, and is measurable using serum C-peptide. Maintaining low-level C-peptide production is therefore a target in therapeutic and transplantation trials. Blood measurement of C-peptide is limited to hospital settings due to its instability in plasma samples. We have developed a simple, stable urine test, urine C-peptide creatinine ratio (UCPCR) that is validated against the standard mixed meal tolerance test, and can be performed at home. This study proposes to utilize this novel test to: (1) Establish the prevalence, underlying aetiology and associated clinical features for detectable C-peptide secretion in 1000 patients with a clinical diagnosis of T1D. (2) Assess the impact of persisting insulin secretion on patients’ glycaemic control, risk of severe hypoglycaemia and microvascular complications in subjects with T1D. (3) Establish the validity and reproducibility of UCPCR in specific patient groups who would benefit from individual regular monitoring of C-peptide such as subjects with islet and pancreas transplants.


Research activity codes: 4.1 DISCOVERY AND PRECLINICAL TESTING OF MARKERS AND TECHNOLOGIES;2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: METABOLIC AND ENDOCRINE
Title: Functional characterization of novel islet G-protein coupled receptors as drug targets for the treatment of diabetes
Funder: Diabetes UK

Abstract: G-protein coupled receptors (GPCRs) play important roles in modern medicine, and they are the targets of more than 50% of all prescription drugs. Approximately 25% of all GPCRs (~100 receptors) have no known endogenous ligands, and identification of ligands for these so-called orphan receptors may enable the development of novel treatments for a number of diseases, including diabetes. In this RD Lawrence Fellowship project proposal I present data demonstrating that two orphan GPCRs, GPRC5B and GPRC5C, transduce the effects of glutamate and retinoic acid on insulin secretion and islet cell survival/apoptosis, respectively, and that the recently deorphanized receptor GPR75 and its peptide ligand CCL5 also regulate islet function. The aim of this fellowship project is to investigate how GPRC5B, GPRC5C and GPR75 regulate insulin secretion and islet cell survival and proliferation, processes that are dysfunctional in the pathogenesis of diabetes. This project has the potential to provide both academia and industry with three novel drug targets for the treatment of diabetes.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: METABOLIC AND ENDOCRINE
Title: A novel growth factor, VEGF165b, as treatment for diabetic neuropathy
Funder: Diabetes UK

Abstract: In Type I diabetes high blood glucose results in damage to blood vessels, and to peripheral sensory neurones, causing diabetic neuropathy. This project will investigate the effect of VEGF165b in diabetic neuropathy. We will determine the effect of VEGF165b on nociceptive behaviour, on the blood vessel endothelial cells, in vessels supplying the affected nerves, and the nerve trunks and cell bodies, in vivo. We will also determine the processes involved in endothelial and neuronal cell damage by high blood glucose levels, and how VEGF165b may effect protection against this damage, in culture systems. This project will determine whether VEGF165b has cytoprotective and analgesic actions in diabetic neuropathy.


Research activity codes: 5.1 PHARMACEUTICALS
Health categories: METABOLIC AND ENDOCRINE
Title: Control of glucagon secretion by AMPK and related kinases.
Funder: Diabetes UK

Abstract: Proper control of blood glucose in man requires the concerted action of both insulin and glucagon which becomes defective in both type 1 and type 2 diabetes. Using a combination of in vivo and ex vivo techniques we have provided evidence that glucose controls the release of glucagon from pancreatic islet alpha -cells through changes in the activity of AMP-activated protein kinase and related kinases including per-arnt-sim kinase (PASK). Here, CreLoxP-mediated deletion of the corresponding genes selectively in the beta-cells of mice will be combined with in vivo and in vitro approaches to explore the regulation of these enzymes in the alpha-cell and their contribution to the control of glucagon release. Specifically, we shall: (1) determine how glucose and other agents, including glucagon-like peptide-1 (GLP-1), control AMPK in the alpha-cell, and identify the upstream AMPK kinase(s); (2) assess the contribution of AMPKalpha1 cand alpha2-containing complexes and related kinases to the control of glucagon gene expression and hormone secretion, and (3) identify novel intracellular effectors for AMPK in alpha-cells using a phosphoproteomic screen. Detailed knowledge of how AMPK and related kinases control glucagon secretion may provide new therapeutic approaches to controlling blood glucose levels in diabetes.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING
Health categories: METABOLIC AND ENDOCRINE
Title: Mechanisms of fructose-induced hepatic insulin resistance
Funder: Diabetes UK

Abstract: Dietary fructose is a likely contributing factor to hepatic insulin resistance and development of fatty liver which predispose to type 2 diabetes. In humans replacement of dietary glucose by fructose aggravates hepatic insulin resistance and dyslipidaemi


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: METABOLIC AND ENDOCRINE
Title: Investigation of an AMPK phosphatase
Funder: Diabetes UK

Abstract: Metformin inhibits mitochondrial complex 1, which causes an increase in the cellular AMP/ATP ratio. The increase in AMP activates AMPK by promoting net phosphorylation on Thr172 of the AMPK alpha-subunit mediated via the kinases LKB1 and CaMKKbeta. Activation of AMPK, which switches on energy consuming and turns off energy promoting pathways, is believed to underlie the main beneficial effects of metformin. A protein phosphatase, Ppm1E, dephosphorylates AMPKa-Thr172 in cell cultures. Since inhibition of AMPKa-Thr172 dephosphorylation would lead to phosphorylation and activation of AMPK, an inhibitor of Ppm1E is likely to be beneficial for the treatment of diabetes. The project aims to examine whether Ppm1E dephosphorylates AMPKalpha-Thr172 in an in vivo mouse model. Part of the single mouse gene encoding Ppm1E will be replaced in mouse embryonic stems cells, so that an inactive Ppm1E is synthesized. Mice derived from these stem cells will be examined phenotypically and biochemically for the expression of inactive Ppm1E, the phosphorylation and activation of AMPK in several tissues and other parameters that are relevant to diabetes. A screen for a small molecule that could form the basis for development of a specific inhibitor of Ppm1E will be performed.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING
Health categories: METABOLIC AND ENDOCRINE
Title: How does tyrosine phosphorylation of Syntaxin 4 and Munc18c control GLUT4 translocation?
Funder: Diabetes UK

Abstract: Insulin binding activates the intrinsic tyrosine kinase activity of the receptor ?-subunit. Although the essential role of two major targets for this kinase, IRS1 and IRS2, in metabolic regulation is clear, little is known about the role of insulin-stimulated tyrosine phosphorylation of other proteins. Syntaxin 4 and Munc18c, proteins intimately involved in the insulin-stimulated translocation of the facilitative glucose transporter, GLUT4, to the plasma membrane (PM) are both tyrosine-phosphorylated within minutes of insulin stimulation, but the functional consequences of these phosphorylation events are not understood. Here we propose systematic in vitro and in vivo analyses of the effects of tyrosine phosphorylation of Syntaxin 4 and Munc18c. This will provide information essential for a detailed molecular description of insulin action. GLUT4 translocation is defective in individuals with insulin resistance and Type-2 diabetes, thus in order to facilitate the rationale design of therapeutic interventions, it is important that GLUT4 translocation is understood at the molecular level.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING
Health categories: METABOLIC AND ENDOCRINE
Title: Using mesenchymal stem cells to improve islet transplantation outcome
Funder: Diabetes UK

Abstract: Islet transplantation as therapy for Type 1 diabetes is limited by the post-transplantation loss of functional islets through deleterious responses to an inflammatory, immunogenic environment. Mesenchymal stem cells (MSCs) have several properties which make them excellent candidates for improving the survival and function of transplanted islets. We and other groups have recently demonstrated beneficial effects of different MSC populations when co-transplanted with islets in animal models of diabetes. In this project we will use our existing experimental model to determine how MSCs improve islet transplantation outcomes by measuring the effects of MSCs on islet survival and function in vitro and in vivo. We will determine which population(s) of MSCs, or other stromal cells, are most effective at supporting islet function, and we will adapt our experimental model to more closely mimic the clinical situation by intraportal delivery of the islet grafts. Finally, we will validate our observations made using mouse islets and MSCs by repeating key experiments using clinically-relevant human islets and MSCs. These experimental studies have the potential to translate into improved protocols for clinical islet transplantation programmes


Research activity codes: 5.2 CELLULAR AND GENE THERAPIES;5.4 SURGERY
Health categories: METABOLIC AND ENDOCRINE
Title: Roles of HLA and B-cells in the regulation of pro- and anti-inflammatory T-cell responses to the IA-2 autoantigen in Type 1 diabetes
Funder: Diabetes UK

Abstract: High-risk diabetes-susceptibility HLA molecules influence progression to Type 1 diabetes by presenting antigenic peptides to T-cells thereby promoting inflammatory beta cell destruction. B-cells also regulate T-cell responses by facilitating antigen uptake, processing and presentation on HLA molecules. The identity of antigenic peptides driving pro-inflammatory responses, the role of B-cells and the impact of HLA on their presentation are poorly characterised. We have shown that T-cell epitopes for HLA-DR4-associated responses to IA-2 are contained within a region of the antigen protected by antibody during proteolytic processing. If true for other responses, identification of peptides remaining bound to diabetes-associated antibodies after protease treatment will facilitate the identification of T-cell epitopes linked to B-cell responses in diabetic patients. In this study, we aim to use MALDI-TOF mass spectrometry to identify peptides eluted from protease-treated complexes of IA-2 with antibodies from diabetic patients of restricted epitope recognition. Alanine-scanning mutagenesis will then be used to identify amino acids within the identified region that form the antibody epitope. Synthetic peptides contained within the protected regions will be tested for ability to stimulate T-cell responses in diabetic patients and to establish links with antibody specificity and HLA alleles. Peptides identified may be exploited for diabetes prevention.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: METABOLIC AND ENDOCRINE
Title: Role of the novel cannabinoid receptor GPR55 in islet function: implications for diabetes therapy
Funder: Diabetes UK

Abstract: G-protein coupled receptors (GPCRs) play important roles in modern medicine, and they are the targets of at least 30% of all prescription drugs. We have made the first identification of the novel cannabinoid GPCR, GPR55, in islets, and our preliminary data indicate that its activation results in potentiation of glucose-stimulated insulin secretion from human islets. This project will focus on the roles played by GPR55 in the regulation of insulin secretion and islet cell proliferation, processes that are dysfunctional in the pathogenesis of diabetes. In particular, we will identify which cells within the islet express GPR55 and establish the profile of islet hormone secretion in response to its activation by pharmacological agonists. Specificity of ligand action will be determined using islets isolated from GPR55 knockout mice, or human islets in which GPR55 expression has been knocked down. As GPR55 is known to be coupled to proliferation of other cell types, we will examine its role in beta-cell replication in obesity and pregnancy, conditions under which beta-cell mass expansion is required to maintain normoglycaemia. We will also identify the intracellular cascades downstream of GPR55 activation in islets, which will present an opportunity to therapeutically target key signalling pathways. Understanding the role of GPR55 in islet physiology has the potential to provide a novel drug target for the treatment of Type 2 diabetes.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING
Health categories: METABOLIC AND ENDOCRINE
Title: Emerging ethnic differences in Type 2 diabetes risk in children of South Asian, African-Caribbean and European origin: the role of childhood diet and eating patterns.
Funder: Diabetes UK

Abstract: Compared with European adults, UK South Asians have markedly and UK African-Caribbeans have moderately increased risks of type 2 diabetes. In our recent Child Heart And Health Study in England (CHASE), we showed that corresponding ethnic differences in insulin resistance and glycated haemoglobin (HbA1c) were apparent by 9-10 years of age. These ethnic differences remain unexplained both in adults and in children. We propose to examine the contributions of childhood diet and eating patterns to emerging individual and ethnic differences in emerging type 2 diabetes risk in childhood, in ~2000 CHASE participants in whom detailed dietary assessments (including both 24 hour diet recall and 4-day dietary diaries) were made, providing information on nutrient intakes, specific food intakes, diet patterns/diet quality and eating patterns. Using this resource, we will examine how diet and eating patterns influence emerging type 2 diabetes risk in childhood and contribute to emerging ethnic differences in type 2 diabetes. The results will inform the development of strategies for early dietary prevention of type 2 diabetes, particularly in high-risk ethnic groups. With an emerging type 2 diabetes epidemic in UK ethnic minority groups, the research is important and timely.


Research activity codes: 2.3 PSYCHOLOGICAL, SOCIAL AND ECONOMIC FACTORS
Health categories: METABOLIC AND ENDOCRINE