Maigen Bethea, PhD
Project Title: "The Role of Gastrointestinal GLP-1R Neurons in Mediating the Glucose-Lowering and Weight Loss Effects of Oral Exendin-4"
Project Summary: Current studies demonstrate a strong correlation between obesity and Type 2 Diabetes (T2D). Therefore, therapeutics that are able to reduce weight loss and lower glucose are cornerstone to T2D treatments. To date, the only drugs on the market that are able to claim this success are glucagon like peptide 1 receptor agonists (GLP-1RAs). However, many of these drugs require injections, thus negatively impacting patient compliance. Oral GLP-1RAs have the capacity to increase patient adherence and make T2D therapies affordable. It is important to note that systemic versus oral administration of GLP-1RAs target different GLP-1R populations. Therefore, it is critical that the GLP-1R populations that mediate the glucose lowering and weight loss effects of orally administered GLP-1RAs are assessed. In this proposal, I will eliminate the neuronal GLP-1R populations within the intestine to determine if they are necessary for the enhanced glucose tolerance and weight loss effects of orally administered GLP-1RAs. Data leveraged from this study will enhance our knowledge of GLP-1 biology and lead to the development of more efficacious drugs.
Holly O'Donnell, PhD
Project Title: "Understanding the Child Experience in the Autoimmunity Screening for Kids (ASK) Study"
Project Summary: Screening for pre-symptomatic type 1 diabetes (T1D) by measuring islet autoantibodies (IA) has historically targeted first-degree relatives of individuals with T1D, but is now rapidly increasing in the general population. Children diagnosed through these studies may experience both immediate and long-term health benefits including lower A1C and impressively low rates of DKA at diagnosis. As screening for IA in the general population expands, there is a critical need to understand factors associated with active participation in screening and monitoring programs as continued engagement with the monitoring protocol is essential for preventing adverse outcomes and offering novel drug interventions to eligible individuals with presymptomatic T1D. Several studies have documented the psychological experience of caregivers whose children are participating in screening and monitoring programs. However, there is an extreme paucity of literature examining the psychological experience of the children themselves. This project will (1) identify caregiver and child demographic, clinical and psychological characteristics associated with optimal participant engagement in IA screening programs and (2) document the experience of children ≥ 10 years of age with confirmed IA+ test results who agree to be monitored. Results will inform future behavioral interventions to increase retention in IA screening and monitoring programs.
Alicia White, PhD
Project Title: "Investigating Fetal Pancreatic β-cell NFκB Signaling as a Novel Pathway Linking Early Metabolic Dysfunction to Type 2 Diabetes Later in Life"
Project Summary: Intrauterine growth restriction (IUGR) increases perinatal morbidity and mortality and results in long-term metabolic consequences, including premature β-cell failure and type 2 diabetes. IUGR fetuses have β-cells that fail to sense intrauterine nutrients properly thereby leading to impaired oxidative metabolism, reduced insulin secretion, and decreased β-cell mass. Oxidative metabolism increases cytoplasmic calcium leading to insulin secretion, suggesting impaired calcium handling within the IUGR β-cell. NFκB is a calcium-sensitive transcription factor that promotes β-cell mass by regulating β-cell replication and apoptosis and is activated in adult β-cells during nutrient stimulation and insulin secretion. Therefore, we propose that evaluating fetal β-cell-specific NFκB activation will uncover a novel mechanism linking intrauterine β-cell failure, lower β-cell mass, and the later development of type 2 diabetes. This will be tested with in vivo and in vitro nutrient and calcium stimulation in chronically catheterized late gestation normally grown fetal sheep for eventual comparison to fetal sheep subjected to experimental IUGR with similar characteristics and complications to human IUGR pregnancies.
Emily Bates, Ph.D. - Associate Professor, Department of Pediatrics
Title: Determining the effect of in utero CBD exposure on eating behaviors, obesity, and insulin resistance
Project Summary: Susceptibility to obesity and Type 2 diabetes can be influenced by the intrauterine environment. Understanding how fetal exposures to substances that impact behavior and metabolism that may contribute to future metabolic disease risk is paramount to combating diabetes. Many women consume marijuana or its non-psychoactive component, cannabidiol (CBD) during pregnancy because it is readily available, can help with nausea, and public perception is that it is safe. However, the long-term effects on the offspring are not known. In adults, CBD may affect metabolic function, energy balance behaviors, and susceptibility to diabetes because it activates peroxisome proliferator-activated receptor (PPAR), which promotes of increased food intake and adiposity. Fetal exposure to another PPAR agonist rosiglitazone reduces expression of multiple components of insulin signaling, glucose transport, and energy sensing/lipid metabolism pathways. While PPAR is expressed in many metabolic tissues, we do not know if CBD exposure in utero is sufficient to induce changes in fetal or postnatal metabolism, behaviors that affect energy balance, or susceptibility to insulin resistance. Maternally consumed CBD diffuses across the placenta to the fetus. Retrospective clinical studies suggest fetal marijuana exposure is associated with lower birth weight and may impact fetal metabolism. However, these studies are limited by inadequate dosing information, inability to distinguish the impact of CBD from the psychoactive marijuana component, tetrahydrocannabinol (THC), and potential concurrent use of nicotine or alcohol. We will perform dose controlled animal studies to reveal whether and how fetal exposure to CBD affects eating behavior, body composition, and susceptibility to insulin resistance.
Nikki Farnsworth, Ph.D. - Assistant Professor, Department of Chemical & Biological Engineering, Colorado School of Mines
Title: Engineered Nanocapsules for Targeted Drug Delivery to the β-Cell in T1D
Project Summary: T1D is characterized by immune-mediated destruction of insulin-producing β-cells in the pancreatic islet. Strategies to prevent β-cell death show promise in halting T1D; however, lack of specific targeting to the β-cell results in off-target effects and reduced treatment efficacy. Targeted drug delivery using nanocapsules (NCs) has emerged as a promising technology for prolonged release of therapeutics in targeted cell types. Several studies have successfully employed Exendin-4 to target diagnostic imaging nanoparticles to the β-cell, but this strategy has not been applied to targeted delivery of small peptides to the β-cell to date. The main goal of this study is to develop a NC drug delivery vehicle that specifically targets the β-cell and delivers a therapeutic peptide to protect against β-cell death in T1D. Overall, this study will utilize a novel NC design to target the β-cell and deliver a small peptide therapeutic to protect against β-cell death. The results from this study will provide the necessary proof of concept data to verify selectivity of NC targeting in mouse and human tissues. Future studies will translate this technology into a mouse model of T1D to determine if it can protect against T1D onset and progression.
Jefferson Knight, Ph.D. - Associate Professor, Department of Chemistry, University of Colorado Denver
Title: Oxidative Stress-Induced Protein Damage in β-cell Secretory Dysfunction
Project Summary: Inflammation produces high levels of reactive oxygen species such as hydrogen peroxide, superoxide, and their downstream products including reactive lipid aldehydes. Such oxidative stress is a key contributor to β-cell failure in both type 1 and type 2 diabetes (T1D and T2D). In T1D, β-cells are damaged due to autoimmune inflammation and lose the ability to secrete insulin prior to their eventual destruction. In T2D, oxidative stress arising in part from inflammatory cytokine signaling is also known to occur prior to β-cell failure, although the molecular mechanisms remain poorly understood. In this project, we will test the hypothesis that oxidative stress impairs insulin secretion via irreversible post-translational modification to membrane trafficking proteins. The project is a collaboration between the principal investigator (Dr. Knight), an established secretory protein biochemist, and Dr. Colin Shearn in the Department of Pediatrics, an expert in oxidative stress and inflammation. In this pilot study, we will identify protein targets of reactive lipid aldehydes in β-cell lines and in cytokine-treated islets using cutting-edge proteomic approaches, and we will quantify the effects of protein modification on secretory function. Our preliminary results suggest that key proteins in the insulin secretory pathway are susceptible to irreversible modification by lipid aldehydes, and that this modification can begin to inhibit insulin secretion within minutes. Results from this basic science study could have significant implications for detecting and understanding early events in β-cell failure that lead to diabetes.
Kathleen Woulfe, Ph.D. - Assistant Professor, Department of Medicine, Division of Cardiology and Geriatric Medicine
Title: Hyperglycemia mediates sarcomeric mechanical function in cardiac and skeletal muscle
Project Summary: Hyperglycemia has been associated with cardiac diastolic dysfunction, which is characterized by impaired relaxation. Specific mechanisms underlying hyperglycemia-induced diastolic dysfunction are unclear. In addition to cardiac sequelae, people with diabetes also report declines in skeletal muscle function, but it is not known if relaxation is altered in skeletal muscle. While aspects of regulation and function are unique between skeletal and cardiac muscle, there is a commonality between the two systems in the organization of the sarcomeres and how the sarcomeric proteins interact to generate force and how they relax. By studying the function of small bundles of sarcomeres (myofibrils), differences in relaxation can be defined. We hypothesize that hyperglycemia alters cardiac and skeletal sarcomeric mechanical function leading to prolonged relaxation. This proposal outlines an innovative concept that sarcomeric function is similarly altered in hearts and skeletal muscles in response to hyperglycemia. If skeletal muscle sarcomeric function is similarly modified by hyperglycemia as cardiac sarcomeric function, it is possible that less invasive biopsies of skeletal muscle may be a mechanism of assessing cardiac sarcomeric function prior to overt organ functional changes.
Srividhya Iyer, Ph.D.- Assistant Professor, Department of Orthopedics
Title: ER stress in prediabetes-associated skeletal fragility
Project Summary: People with diabetes who are obese and people with prediabetes are predisposed to higher fracture incidence and poor bone healing outcomes, but the basis of impaired osteogenesis remains unclear. Accumulation of misfolded proteins results in ER stress and mediates progression of multiple diabetic comorbidities. In preliminary studies, we found that the hyperglycemic obese mice had reduced bone mass and diminished bone healing following fracture. Osteoblast cultures obtained from marrow of obese mice exhibited elevated bioenergetics concomitant with higher respiratory complex V protein levels. Additionally, obese mice had dilated ER in the osteoblasts as well as elevated PERK and ATF6 activity in cortical bone. These findings suggest that impaired osteogenic response partly due to disruption of ER homeostasis could impede fracture repair in the setting of obesity. Studies in Aim 1 will examine the effect of obesity-associated diabetes on osteoprogenitors that contributes to delayed healing in vivo, using reporter mice by flow sorting and histologic imaging. Additional bioenergetic and transcriptomic studies will reveal changes to pathways affected by obesity in osteoblast progenitors. In Aim 2 we will test the therapeutic efficacy of the ER stress inhibitor TUDCA in improving fracture deficits of the obese mice.
Jordan Jacobelli, Ph.D.- Associate Professor, Department of Immunology and Microbiology
Title: Cytoskeletal regulation of self-reactive T cell restimulation and effector functions in the pancreatic islets
Project Summary: Islet-specific T cell entry in the islets and antigenic restimulation at the disease site are key steps leading to islet destruction in type 1 diabetes (T1D). The T cell cytoskeleton plays a crucial role in regulating T cell migration and interaction with Antigen Presenting Cells (APC) and target cells. However, there is a key knowledge gap about the mechanism by which specific cytoskeletal effectors regulate T cell functions at the autoimmune disease site. Formin-like-1 (FMNL1) is a cytoskeletal effector highly expressed in T cells. Our data show that FMNL1 knock-out (KO) T cells are significantly impaired in inducing T1D in a mouse T cell transfer model. Furthermore, our preliminary data show that FMNL1-deficient T cells have impaired motility within lymph nodes and reduced T cell-APC interactions. Based on these data, we hypothesize that FMNL1-deficient islet-reactive T cells are less pathogenic due to reduced migration, activation and effector functions within the pancreatic islets. We will employ a multi-pronged approach, including genetic, immunological, and in vivo imaging techniques, to determine the role of FMNL1 in auto-reactive T cell pathology in T1D. Our work will also validate FMNL1 as a potential target to inhibit T cell mediated pathogenesis as a treatment for T1D.
Laurel Messer, Ph.D., RN- Assistant Professor of Pediatrics, Barbara Davis Center
Title: Development of a “Cognitive Awareness Artificial Pancreas Enhancement” (CAPE) to Help Adolescents with Type 1 Diabetes Optimize their use of Artificial Pancreas Systems
Project Summary: Adolescents with type 1 diabetes (T1D) demonstrate suboptimal glycemic control and self management behaviors, even when using sophisticated artificial pancreas (AP) systems. The purpose of this proposal is to develop a “cognitive awareness” AP enhancement (CAPE) to “nudge” adolescents, via adaptive prompts based on current cognitive resources and behavioral tendencies, to improve their diabetes self-care with AP system, ultimately improving glycemic control. This will be done by first collecting real-time physiological, psychological, and behavioral inputs from adolescents who use AP systems. Next, these data will be used to create mental models based on the user’s awareness of their blood glucose levels, their ability to plan near-term actions around insulin boluses and meals and their overall cognitive load. Finally, we will use these mental models to create and pilot the CAPE algorithm, which will provide the AP user with carefully designed “nudges” to enhance self-management behavior. Nudges are environmental design factors or that affect people’s behavior outside their awareness, which can be used to encourage healthy choices by children and adolescents. A cognitively aware AP system is needed because effective “nudging” depends on optimal timing and situational awareness of the user, and current systems lack this level of modeling.
Kalie Tommerdahl, MD- Instructor, Department of Pediatrics, Section of Endocrinology
Title: Metformin and Automated Insulin Delivery System Effects on Renal Vascular Resistance and Vascular and Endothelial Function in Youth with Type 1 Diabetes Pilot Study
Project Summary: Diabetic kidney disease (DKD) and cardiovascular disease (CVD) remain the leading causes of morbidity and mortality in people with type 1 diabetes (T1D) and are exacerbated by longer diabetes duration and time outside goal glycemic range. Yet, T1D pathophysiology extends beyond beta cell injury and insulin deficiency and includes insulin resistance (IR), possibly secondary to excess peripheral insulin exposure, and renal vascular resistance (RVR), factors that accelerate CVD risk. We demonstrated metformin improved peripheral insulin sensitivity (IS) and vascular stiffness in youth with T1D on insulin injections or standard insulin pumps. However, metformin's effects on kidney and endothelial outcomes, and the effects of advanced diabetes technologies plus metformin on any cardiovascular or kidney outcome, remains unknown. Automated insulin delivery (AID) systems combine an insulin pump, continuous glucose monitor, and control algorithm to modulate background insulin, decrease peripheral insulin exposure, improve time in target range, and reduce hypoglycemia. We hypothesize that AID systems plus metformin may modulate RVR and vascular/endothelial function, thereby affecting cardiometabolic function, and propose an open label pilot study of 3 months metformin 2,000mg daily in 12 youth (12-21 years) with T1D on AID systems to evaluate for changes in gold-standard measures of RVR, arterial stiffness, and endothelial function.
Petter Bjornstad, MD- Assistant Professor of Pediatrics and Medicine
Title: Spatial metabolomics for human kidney interrogation of early diabetic kidney disease
Project Summary: Kidney hypoxia, stemming from a mismatch between increased renal energy demand and impaired substrate metabolism, is emerging as a unifying early pathway in the development of diabetic kidney disease (DKD) and a potential therapeutic target. In our JDRF-funded CROCODILE study we are quantifying kidney O2 consumption by 11C-acetate PET, kidney oxygenation by blood oxygen level dependent MRI, glomerular filtration rate and renal plasma flow by iohexol and p-aminohippurate clearances, morphometric and transcriptomic analyses of kidney tissue from research biopsies, insulin sensitivity by hyperinsulinemic-euglycemic clamp and mitochondrial function by plasma and urine metabolomics in young adults with and without type 1 diabetes (T1D). However, plasma and urine metabolomics are not kidney-specific and identified compounds may not be representative of the intrarenal milieu. Accordingly, metabolic phenotyping of the kidney tissue to interrogate tissue-specific metabolic perturbations of early DKD in T1D would enhance our study design. The DRC P&F Grant would provide support to add spatial metabolomics analyses of kidney tissues by matrix-assisted laser desorption/ ionization mass spectrometry imaging from young adults with (n=20) and without (n=20) T1D. Our central objective is to quantify metabolite data in discrete kidney compartments in order to define the metabolic pathways that may drive early DKD in T1D.
Sridharan Raghavan, MD, Ph.D.-Attending Physician, Rocky Mountain Regional VA Medical Center; Assistant Professor, University of Colorado School of Medicine
Title: Evaluating Genetic Tools for Diabetes Precision Medicine in Clinical Biobanks
Project Summary: Diabetes mellitus is heterogeneous, making it an ideal disease for precision medicine that individualizes treatment to maximize benefit and minimize harm. One axis of heterogeneity is the distinction between type 1 (T1D) and type 2 diabetes (T2D). Failure to recognize the disease subtype can lead to delays in treatment intensification and eventually to diabetes complications. A second important context for heterogeneity in diabetes care is in response to medications where favorable glycemic response must be balanced against the risk of hypoglycemia, a treatment-related adverse event. Recent advances in the genetics of T1D, T2D, response to metformin and sulfonylureas, and hypoglycemia have set the stage for studies evaluating how genetic information can be applied to clinical care using clinical biobanks with data representative of the real world diabetes patient population. In this study, we will complete two aims: 1) Test whether T1D and T2D genetic risk scores predict diabetes type and time to insulin dependence in two clinical biobanks; and 2) Evaluate metformin-, sulfonylurea-, and hypoglycemia-associated genetic variants as tools to guide oral diabetes medication choice. By exploring the relationships of diabetes-related genetic loci with aspects of patient care, we aim to make a translational research impact on precision diabetes care.
Mia Smith DVM, Ph.D.- Assistant Professor, Department of Pediatrics and the Barbara Davis Center for Diabetes
Title: Decoding the B cell endotype in early onset T1D
Project Summary: Recent studies indicate the existence of two forms of type 1 diabetes distinguished by the age of onset. Importantly, one of the major defining characteristics between the two forms of disease is the presence of increased numbers of B cells in early onset T1D (<7 years) compared to late onset (>13 years). The increased numbers of B cells is associated with, and can even predict, rapid progression of disease as evidence by increased loss of C-peptide. Despite the compelling evidence for a role of B cells in an aggressive form of T1D, it remains unknown which B cell subset(s) is the pathogenic offender, as well as its phenotype, activation, and functional status. This application seeks to address this deficit in our knowledge by comparing the B cell compartment in early onset to late onset and healthy controls using the most comprehensive B cell panel (>35 markers) used to date and high-dimensional mass cytometry (CyTOF). The significance of this proposal is that it aims to improve human health by developing fundamental knowledge in our understanding of the molecular mechanism of B cell involvement in rapid rate of progression, which may translate into future novel therapeutic targets to treat disease.
Clyde Wright, MD -Associate Professor of Pediatrics
Title: Pathogenic Role of IκBβ/NFκB signaling in ER Stress Induced β-cell Injury and Death
Project Summary: Intrauterine growth restriction (IUGR) is defined as a failure of the developing fetus to reach its genetic growth potential. IUGR is a well-established independent risk factors for the development of Type II diabetes (T2DM) in adulthood. It is increasingly recognized that T2DM is a chronic inflammatory disease. The transcription factor NFκB has been termed the “master regulator the inflammatory response,” and is a well-studied mediator of innate immunity. Multiple studies have implicated NFκB activity as a central mediator of β-cell apoptosis downstream of ER stress. Our lab is new to the study of diabetes, but the rigor of published research, together with our preliminary data, have led us to develop our overarching hypothesis that IUGR β-cell IκB expression favoring IκBβ/NFκB signaling increases sensitivity to ER stress and contributes to an increased risk of developing T2DM.