Our Diabetes Research Projects

Sebastian Kalamajski, Hjelt Grant Holder 2024, Lund University. Leveraging discordancy between obesity and type 2 diabetes to target insulin resistance

Sabrina Ruhrmann, Hjelt Grant Holder 2023, Lund University. Epigenetic Editing - a way to a personalized treatment approach in type 2diabetes (T2D) The number of people affected by diabetes is rapidly increasing worldwide. Type 2 diabetes (T2D) largely contributes to this increase and individuals with T2D usually face high blood sugar levels. To balance our blood sugar level the hormone Insulin is necessary and Insulin target tissues like muscles need to be able to take up glucose in response to Insulin. Overweight and no physical exercise can lead to insulin resistance (where the uptake of glucose is not any longer possible e.g. in our muscles) and almost all individuals with T2D show Insulin resistance. Our DNA only explains a small proportion of how T2D is passed on from parents to their children (also described as the so called “missing heritability”). Given the crucial role of diet and physical exercise in the development of T2D, mechanisms mediating the interaction of those factors with our genes should be of particular importance when trying to explain how T2D develops. Epigenetic mechanisms fulfil this criterion. Epigenetics is the study of how e.g. the environment and/or our behavior can affect the expression of our genes without changing our DNA. The fact that epigenetic changes do not change our DNA unlike genetic changes gives us the opportunity to “correct“ them. We are here trying to discover epigenetic changes that cause T2D. We will create small molecules called guideRNAs (gRNAs) that will help us to search for those epigenetic changes using the so called inactivated gene scissor system, CRISPR-dCas9. We will further try to also 'correct' these epigenetic changes to explore if epigenetic mechanisms may be targeted for a more patient specific treatment of T2D in the future.

Monika Gjorgijeva Ducros, Hjelt Grant Holder 2022, University of Geneva. Background MicroRNAs (miRNAs) are critical gene expression regulators involved in mRNA decay or translation inhibition. MiRNAs play an important role in various physiological processes and therefore, deregulation of their expression/activity has been associated with the development of metabolic disorders. Obesity and the metabolic syndrome represent key etiological conditions that predispose to the development of insulin resistance (IR), Type 2 Diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD). Increasing evidence indicate that miRNA deregulation contributes to the development of these diseases. In this context, our recent findings highlighted a strong induction of miR-149 in the liver of various models of IR, T2D and NAFLD, suggesting an important role of this miRNA in these metabolic disorders. Hypothesis Based on our preliminary results, we hypothesize that the increase in hepatic mir-149 in IR/T2D/NAFLD conditions can favor these pathologies. We will therefore investigate i) the pathophysiological role and pre-clinical relevance of miR-149 upregulation in IR/T2D/NAFLD and ii) which miR-149 target genes are involved in this process. Methods To investigate the role of miR-149 in IR/T2D/NAFLD, we are using human liver organoids (HLOs). HLOs are obtained by inducing differentiation of human progenitor cells into different hepatic cell types (hepatocytes, Kuppfer cells, stellate cells) that form functional structures. These organoids respond to insulin stimulation in the same manner as human liver. Moreover, they develop hepatic steatosis under high-fat/high sugar conditions and can undergo inflammation when stimulated with cytokines. Finally, HLOs are an extremely relevant experimental model as they allow us to avoid animal experimentation protocols. Therefore, we will modulate the expression of miR-149 in HLOs via synthetic nucleotides and/ or viral vectors and we will analyze the molecular responses in HLO under various metabolic / inflammatory stimuli. We will further identify miR-149 target genes involved in IR/T2D/NAFLD and we will validate their relevance in public human datasets. Results Our preliminary data suggest a pertinent role for miR-149 upregulation in the induction of steatosis in vitro in currently used hepatic cell lines, as well as in HLO. We have also observed that alteration of miR-149 levels has a striking effect on hepatic glucose and lipid metabolism, implying a functional role for this miRNA in IR/T2D/NAFLD. Conclusion This project should allow us to better understand the role of miR-149 in hepatic IR, and more generally in obesity-associated disorders of the hepatic lipid/glucose metabolism. We will identify novel target genes of miR-149 contributing to IR/T2D/NAFLD and the fine-tuning metabolic regulation in the liver in pathophysiological conditions. Our investigations should provide key evidence and proof-of-concept about the potential of miR-149 and its targets as new biomarkers for IR/T2D as well as the therapeutic potential of targeting this miRNA to counteract and/or to alleviate IR/T2D development. Importance Modulation of miR-149 represents a promising therapeutic strategy by targeting numerous genes at once. Therefore, miR-149 modulation could represent a multi-targeting approach relevant and pertinent for multifactorial disorders such as obesity, IR/T2D/NAFLD. A significant and innovative aspect of this proposal is the development and use of genetically engineered functional HLOs in which hepatic steatosis, inflammation and IR can be reproduced. HLOs have the potential of replacing animal experimentation, thereby alleviating important ethical issues related to the use of laboratory mice for pre-clinical research.

Rodrigo Cataldo, Hjelt Grant Holder 2022, Lund University. Background The role of beta cells is to sense glucose and response by releasing insulin to maintain glucose homeostasis. Consequently, the loss of beta cell function is the main culprit of type 2 diabetes development. Ependymin-related protein 1 (EPDR1) was recently identified as a protein released by the human brown adipose tissue, where it plays a role in regulating thermogenesis, a protective metabolic process that transform stored fat into heat. It was suggested that EPDR1 may act as a novel hormone regulating whole-body energy metabolism. Apart of this, the biological role of EPDR1 is poorly known. I have identified that human beta cells also produce EPDR1 protein and that its expression is upregulated in pancreatic islets from Type 2 diabetes vs. non diabetic donors and that its expression is associated to beta cell function. Hypothesis Based on the data obtained so far, I believe that EPDR1 expression in beta cells may increase in response to the metabolic stress caused by overfeeding in obese people to, in a compensatory fashion, restore glucose metabolism and maintain beta cell function. Methods I aim to apply a cutting-edge methodology, Metabolic Flux Analysis (MFA), which is based in fueling beta cells with labeled energy substrates and then quantify the rate of different metabolic pathways underlying insulin secretion. With this method we plan to elucidate the mechanism of action for EPDR1 in regulating beta cell function. I also plan to study animals that lack EPDR1, make them obese (to mimic metabolic stress in obese people) and test beta cell function (in vitro) and glucose tolerance (in vivo) to understand the role of EPDR1 in beta cell function and glucose homeostasis. Results I have so far conducted some in vitro experiments and found that treatment of beta cells with EPDR1 protein increases insulin secretion whereas silencing EPDR1 expression reduces insulin secretion. I have performed metabolomics experiments and found that silencing EPDR1 expression in beta cells alter the levels of glucose-derived metabolites in different relevant pathways associated to insulin secretion. Conclusions I have found that EPDR1 is required to maintain normal human beta cell function. EDPR1 regulates glucose metabolism by increasing coupling of glycolysis and mitochondrial function in beta cells. Importance The proposed research project will help to elucidate the role of EPDR1 for beta cell function and glucose homeostasis and to deepen the knowledge of molecular mechanisms of EPDR1 to regulate beta cell metabolism and function. We have also identified genetic variants associated to EPDR1 expression in human beta cells and function and this study will also explore the potential of these genetic variants to make advances of precision medicine in Type 2 diabetes. Finally, if we confirm the positive effects of EPDR1 protein for human beta cell function and glucose homeostasis, EPDR1 could become a target to develop treatments for obese people to prevent progress to T2D.

Sebastian Kalamajski, Hjelt Grant Holder 2022, Lund University. Background Our health relies on a proper balance between energy intake, storage, and expenditure. To accomplish that, a number of genes act as responders to the continuously changing calorie intake, and can direct our fat cells to either store or degrade the calories, depending on our needs. One of those genes is called PPARGC1A, and an estimated 43% of the people globally carry a genetic variant of PPARGC1A that associates with obesity and diabetes. Our goal is to investigate whether this variant not merely correlates, but causes changes in fat cells that make them more or less responsive to calorie intake. Why this is of concern is that a disturbed fat storage capacity leads to insulin resistance and diabetes. In the end, our aim is to create guidelines for precision medicine treatment of obesity and diabetes, based on what genetic variants the individuals are carrying in their DNA. Hypothesis We think the genetic variant in the PPARGC1A gene somehow alters the production and/or degradation of the protein (called PGC-1alpha), which in turn would affect how fast a cell can respond to calorie intake or fasting. This would effectively change how much fat is being stored or removed from a fat cell, and would help predict the effect of the genetic variants on obesity and diabetes. Methods We can genomically edit fat cells for the different genetic variants using CRISPR-Cas9 toolkit. The edited cells are then analyzed for their specialized fat cell properties, including capacity to store and release fat under different environmental changes, including calorie restriction or cold exposure. Our results will later guide us in the design of clinical studies where we can assess the combined influence of the different environmental factors and genetic variation on e.g. weight loss. Results We have genomically edited several cell populations for the obesity-associated genetic variant of PPARGC1A. We have also generated cells that allow us to follow the turnover of the PGC-1alpha protein over time, under different environmental conditions. So far, we have observed rather dramatic effects of one of the genetic variants on the fat cell lipid storage capacity, and also a clear effect of the variant on PGC-1alpha protein stability. Conclusions To this end, we have observed clear causal effects of the genetic variants in the PPARGC1A gene on the produced PGC-1alpha protein stability, and on overall fat cell properties. More studies are underway with regards to the effects of different environmental factors and PPARGC1A variants on the fat cell lipid storage and release. Importance Almost half of the human population is carrying a genetic variant in PPARGC1A that seems to cause profound effects on fat cell capacity of storing or releasing lipids. This information could guide future precision medicine-based treatments of obesity and diabetes.

Anja Schmidt-Christensen, Hjelt Grant Holder 2022, Lund University. Synchrotron X-ray micro-CT imaging for resolving complex 3D structural changes in the kidney: a missing piece of information needed to understand and potentially predict DKD progression and response to treatment Diabetic Kidney Disease (DKD) is a common complication of diabetes, and is characterized by a gradual loss in kidney function, eventually leading to end-stage renal disease which requires dialysis or kidney transplantation. The kidney is a very important organ for continued good health because it acts as a filter to extract waste and excess water from blood. The visualization of complex renal 3D functional units with micrometer precision and early microstructural changes in DKD may help redefine the way DKD is understood and treated. Here we use high-resolution Synchrotron X-ray micro-CT to image biopsies from both patients with DKD and animal models, to get a better understanding of how adaptive morphological and functional changes in the chronically diseased kidney develop. The working principle of the X-ray imaging we use is not any different from that used in common medical radiology known as CT scan, however synchrotron light – is unique! A Synchrotron source is about a hundred billion times brighter than a hospital X-ray source and can therefore provide us with more detailed information related to injuries and/or diseases of the kidneys. With this technique we can finally resolve complex 3D microstructures with a mesoscale window and potentially uncover local structure-specific alterations in disease or after drug treatment that could otherwise be missed in 2D histology.

Ola Hansson, Hjelt Grant Holder 2021, Lund University. When we eat a meal, the pancreas secretes insulin to signal that energy is plenty and should be harvested. High insulin means that energy stores should not be used but replenished. If a person has type 2 diabetes, this system is not functioning properly. We talk about the two hallmarks of type 2 diabetes, i.e. (1) decreased insulin secretion from the pancreas and (2) decreased insulin sensitivity of target tissues like fat, muscle and the liver. This leads to abnormally high blood glucose levels, which is the definition of diabetes. The largest user of glucose in the body is by far skeletal muscle. When we get older our muscles are getting less and less sensitive to insulin, but this can be counteracted by physical exercise. Today we have ways to pharmacologically stimulate the pancreas to enhance insulin secretion, but unfortunately after many years of research, still no drug to enhance insulin sensitivity specifically targeting skeletal muscle. Reasons for this lack of success could be many, but differences in muscle function and metabolism between humans and model organisms commonly used in research is probably contributing. The aim of this project is to use novel methods to finally identify pharmacological targets to specifically increase muscle insulin sensitivity. We will test two different approaches. In aim I, we will take advantage of naturally occurring rare mutations that may change muscle insulin sensitivity in humans. By sequencing the DNA of ~10.000 individuals, we have already identified one such candidate in the MSS51 gene. A mutation carried by 139 individuals. This gene is only activated in skeletal muscle and has previously been linked to diabetes in rodent studies. We will now invite mutation carriers and measure their insulin sensitivity. Muscle stem cells will be isolated from biopsies to study how insulin sensitivity may be influenced by MSS51. With this study we will be able to test if MSS51 is associated with diabetes also in humans. In aim II we will investigate if a biological mechanism called splicing may be used to develop a completely new type of drugs to increase muscle insulin sensitivity. Taken together, this project will explore new approaches to elucidate the underlying mechanisms of insulin sensitivity in humans with the goal of identifying novel pharmacological targets to improve muscle health.

Malin Fex, Hjelt grant holder 2021, Lund University. Metabolism of nutrients in our body is regulated mainly by two hormones; insulin...

Volodymor Petrenko, Hjelt Grant Holder 2021, Univeristy of Geneva. The circadian clock system (from Latin “circa diem”, about a...