scholarly journals PPARs and the Development of Type 1 Diabetes

PPAR Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Laurits J. Holm ◽  
Mia Øgaard Mønsted ◽  
Martin Haupt-Jorgensen ◽  
Karsten Buschard

Peroxisome proliferator-activated receptors (PPARs) are a family of transcription factors with a key role in glucose and lipid metabolism. PPARs are expressed in many cell types including pancreatic beta cells and immune cells, where they regulate insulin secretion and T cell differentiation, respectively. Moreover, various PPAR agonists prevent diabetes in the non-obese diabetic (NOD) mouse model of type 1 diabetes. PPARs are thus of interest in type 1 diabetes (T1D) as they represent a novel approach targeting both the pancreas and the immune system. In this review, we examine the role of PPARs in immune responses and beta cell biology and their potential as targets for treatment of T1D.

2020 ◽  
Vol 1 (3) ◽  
pp. 40-54
Author(s):  
Sumbal Sarwar ◽  
Shabana

Peroxisome proliferator-activated receptors are a group (PPARs) of transcription factors whose differential distribution in different tissues, including adipocytes, hepatocytes, musclesand endothelial cells lead to different clinical outcomes. They are called lipid and insulin sensors due to the important role in lipid and glucose homeostasis. They are mainly of threetypes; 1) PPAR? which influences fatty acid metabolism and its activation lowers lipid levels,2) PPAR? causes fatty acid oxidation in skeletal and cardiac muscles, as well as regulatesblood glucose and cholesterol levels and 3) PPAR? which is mostly involved in the regulationof the adipogenesis, energy balance, and lipid biosynthesis. The expression of these receptorsis influenced by many natural and synthetic ligands. Realistic data on the expression andfunction of natural PPAR agonists on glucose and lipid metabolism are still missing, mostlybecause the same ligand influences several receptors and a number of reports have providedconflicting results. The current minireview focuses on the structure, functions, types andligands of the PPAR.


Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1638 ◽  
Author(s):  
Anne Fougerat ◽  
Alexandra Montagner ◽  
Nicolas Loiseau ◽  
Hervé Guillou ◽  
Walter Wahli

Non-alcoholic fatty liver disease (NAFLD) is a major health issue worldwide, frequently associated with obesity and type 2 diabetes. Steatosis is the initial stage of the disease, which is characterized by lipid accumulation in hepatocytes, which can progress to non-alcoholic steatohepatitis (NASH) with inflammation and various levels of fibrosis that further increase the risk of developing cirrhosis and hepatocellular carcinoma. The pathogenesis of NAFLD is influenced by interactions between genetic and environmental factors and involves several biological processes in multiple organs. No effective therapy is currently available for the treatment of NAFLD. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that regulate many functions that are disturbed in NAFLD, including glucose and lipid metabolism, as well as inflammation. Thus, they represent relevant clinical targets for NAFLD. In this review, we describe the determinants and mechanisms underlying the pathogenesis of NAFLD, its progression and complications, as well as the current therapeutic strategies that are employed. We also focus on the complementary and distinct roles of PPAR isotypes in many biological processes and on the effects of first-generation PPAR agonists. Finally, we review novel and safe PPAR agonists with improved efficacy and their potential use in the treatment of NAFLD.


PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Mark A. Deeg ◽  
Meng H. Tan

Peroxisome proliferator-activated receptors (PPARs) play an important role in regulating both glucose and lipid metabolism. Agonists for both PPAR and PPAR have been used to treat dyslipidemia and hyperglycemia, respectively. In addition to affecting glucose metabolism, PPAR agonists also regulate lipid metabolism. In this review, we will focus on the randomized clinical trials that directly compared the lipid effects of the thiazolidinedione class of PPAR agonists, pioglitazone and rosiglitazone, head-to-head either as monotherapy or in combination with other lipid-altering or glucose-lowering agents


2020 ◽  
Vol 28 ◽  
Author(s):  
Seyed Mohammad Nabavi ◽  
Kasi Pandima Devi ◽  
Sethuraman Sathya ◽  
Ana Sanches-Silva ◽  
Listos Joanna ◽  
...  

: Obesity is a major health concern for a growing fraction of the population, with the prevalence of obesity and its related metabolic disorders not being fully understood. Over the last decade, many attempts have been undertaken to understand the mechanisms at the basis of this condition, in which the accumulation of fat occurring in adipose tissue, leads to the pathogenesis of obesity related disorders. Among the most recent studies, those on Peroxisome Proliferator Activated Receptors (PPARs) revealed that these nuclear receptor proteins acting as transcription factors, among others, regulate the expression of genes involved in energy, lipid, and glucose metabolisms, and chronic inflammation. The three different isotypes of PPARs, with different tissue expression and ligand binding specificity, exert similar or overlapping functions directly or indirectly linked to obesity. In this study, we reviewed the available scientific reports concerning the PPARs structure and functions, especially in obesity, considering both natural and synthetic ligands and their role in the therapy of obesity and obesity-associated disorders. In the whole, the collected data show that there are both natural and synthetic compounds that show beneficial promising activity as PPAR agonists in chronic diseases related to obesity.


Science ◽  
2021 ◽  
Vol 373 (6554) ◽  
pp. 510-516
Author(s):  
Jeffrey A. Bluestone ◽  
Jane H. Buckner ◽  
Kevan C. Herold

Type 1 diabetes (T1D) is an autoimmune disease in which T cells attack and destroy the insulin-producing β cells in the pancreatic islets. Genetic and environmental factors increase T1D risk by compromising immune homeostasis. Although the discovery and use of insulin have transformed T1D treatment, insulin therapy does not change the underlying disease or fully prevent complications. Over the past two decades, research has identified multiple immune cell types and soluble factors that destroy insulin-producing β cells. These insights into disease pathogenesis have enabled the development of therapies to prevent and modify T1D. In this review, we highlight the key events that initiate and sustain pancreatic islet inflammation in T1D, the current state of the immunological therapies, and their advantages for the treatment of T1D.


2019 ◽  
Author(s):  
Colleen M. Elso ◽  
Nicholas A. Scott ◽  
Lina Mariana ◽  
Emma I. Masterman ◽  
Andrew P.R. Sutherland ◽  
...  

AbstractType 1, or autoimmune, diabetes is caused by the T-cell mediated destruction of the insulin-producing pancreatic beta cells. Non-obese diabetic (NOD) mice spontaneously develop autoimmune diabetes akin to human type 1 diabetes. For this reason, the NOD mouse has been the preeminent murine model for human type 1 diabetes research for several decades. However, humanized mouse models are highly sought after because they offer both the experimental tractability of a mouse model and the clinical relevance of human-based research. Autoimmune T-cell responses against insulin, and its precursor proinsulin, play central roles in the autoimmune responses against pancreatic beta cells in both humans and NOD mice. As a first step towards developing a murine model of the human autoimmune response against pancreatic beta cells we set out to replace the murine insulin 1 gene (Ins1) with the human insulin gene (INS) using CRISPR/Cas9. Here we describe a NOD mouse strain that expresses human insulin in place of murine insulin 1, referred to as HuPI. HuPI mice express human insulin, and C-peptide, in their serum and pancreata and have normal glucose tolerance. Compared with wild type NOD mice, the incidence of diabetes is much lower in HuPI mice. Only 15-20% of HuPI mice developed diabetes after 300 days, compared to more than 60% of unmodified NOD mice. Immune-cell infiltration into the pancreatic islets of HuPI mice was not detectable at 100 days but was clearly evident by 300 days. This work highlights the feasibility of using CRISPR/Cas9 to create mouse models of human diseases that express proteins pivotal to the human disease. Furthermore, it reveals that even subtle changes in proinsulin protect NOD mice from diabetes.


2021 ◽  
Vol 12 ◽  
Author(s):  
Kriti Joshi ◽  
Fergus Cameron ◽  
Swasti Tiwari ◽  
Stuart I. Mannering ◽  
Andrew G. Elefanty ◽  
...  

Induced pluripotent stem cell (iPSC) technology is increasingly being used to create in vitro models of monogenic human disorders. This is possible because, by and large, the phenotypic consequences of such genetic variants are often confined to a specific and known cell type, and the genetic variants themselves can be clearly identified and controlled for using a standardized genetic background. In contrast, complex conditions such as autoimmune Type 1 diabetes (T1D) have a polygenic inheritance and are subject to diverse environmental influences. Moreover, the potential cell types thought to contribute to disease progression are many and varied. Furthermore, as HLA matching is critical for cell-cell interactions in disease pathogenesis, any model that seeks to test the involvement of particular cell types must take this restriction into account. As such, creation of an in vitro model of T1D will require a system that is cognizant of genetic background and enables the interaction of cells representing multiple lineages to be examined in the context of the relevant environmental disease triggers. In addition, as many of the lineages critical to the development of T1D cannot be easily generated from iPSCs, such models will likely require combinations of cell types derived from in vitro and in vivo sources. In this review we imagine what an ideal in vitro model of T1D might look like and discuss how the required elements could be feasibly assembled using existing technologies. We also examine recent advances towards this goal and discuss potential uses of this technology in contributing to our understanding of the mechanisms underlying this autoimmune condition.


2021 ◽  
Author(s):  
Monica Westley ◽  
Tiffany Richardson ◽  
Suhana Bedi ◽  
Baofeng Jia ◽  
Fiona S.L. Brinkman ◽  
...  

Abstract    A variety of islet autoantibodies (AAbs) can predict and possibly dictate eventual type 1 diabetes (T1D) diagnosis. Upwards of 75% of those with T1D are positive for AAbs against glutamic acid decarboxylase (GAD65), a producer of gamma-aminobutyric acid (GABA) in human pancreatic beta cells. Interestingly, bacterial populations within the human gut also express GAD65 and produce GABA. Evidence suggests that dysbiosis of the microbiome may correlate with T1D pathogenesis and physiology. Therefore, autoimmune linkages between the gut microbiome and islets susceptible to autoimmune attack need to be further elucidated. Utilizing silico analyses, we show here that 25 GAD sequences from different human gut bacterial sources show sequence and motif similarities to human beta cell GAD65. Our motif analyses determined that a majority of gut GAD sequences contain the pyroxical dependent decarboxylase domain of human GAD65 which is important for its enzymatic activity. Additionally, we showed overlap with known human GAD65 T-cell receptor epitopes which may implicate the immune destruction of beta cells. Thus, we propose a physiological hypothesis in which changes in the gut microbiome in those with T1D result in a release of bacterial GAD, thus causing miseducation of the host immune system. Due to the notable similarities, we found between humans and bacterial GAD, these deputized immune cells may then go on to target human beta cells leading to the development of T1D.


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