scholarly journals Pancreatic beta cell autophagy is impaired in type 1 diabetes

Diabetologia ◽  
2021 ◽  
Author(s):  
Charanya Muralidharan ◽  
Abass M. Conteh ◽  
Michelle R. Marasco ◽  
Justin J. Crowder ◽  
Jeroen Kuipers ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Type 1 Diabetes ◽  
Beta Cell ◽  
Beta Cells ◽  
Nod Mice ◽  
Organ Donors ◽  
Oxygen Species ◽  
Tissue Sections ◽  
Human Type

Abstract Aims/hypothesis Pancreatic beta cells are subjected to exogenous damaging factors such as proinflammatory cytokines or excess glucose that can cause accumulation of damage-inducing reactive oxygen species during the pathogenesis of diabetes. We and others have shown that beta cell autophagy can reduce reactive oxygen species to protect against apoptosis. While impaired islet autophagy has been demonstrated in human type 2 diabetes, it is unknown if islet autophagy is perturbed in the pathogenesis of type 1 diabetes. We hypothesised that beta cell autophagy is dysfunctional in type 1 diabetes, and that there is a progressive loss during early diabetes development. Methods Pancreases were collected from chloroquine-injected and non-injected non-obese diabetes-resistant (NOR) and non-obese diabetic (NOD) mice. Age- and BMI-matched pancreas tissue sections from human organ donors (N = 34) were obtained from the Network for Pancreatic Organ Donors with Diabetes (nPOD). Tissue sections were stained with antibodies against proinsulin or insulin (beta cell markers), microtubule-associated protein 1 light chain 3 A/B (LC3A/B; autophagosome marker), lysosomal-associated membrane protein 1 (LAMP1; lysosome marker) and p62 (autophagy adaptor). Images collected on a scanning laser confocal microscope were analysed with CellProfiler and ImageJ. Secondary lysosomes and telolysosomes were assessed in electron micrographs of human pancreatic tissue sections (n = 12), and energy dispersive x-ray analysis was performed to assess distribution of elements (n = 5). Results We observed increased autophagosome numbers in islets of diabetic NOD mice (p = 0.008) and increased p62 in islets of both non-diabetic and diabetic NOD mice (p < 0.001) vs NOR mice. There was also a reduction in LC3–LAMP1 colocalisation in islets of diabetic NOD mice compared with both non-diabetic NOD (p < 0.001) and NOR mice (p < 0.001). Chloroquine elicited accumulation of autophagosomes in the islets of NOR (p = 0.003) and non-diabetic NOD mice (p < 0.001), but not in islets of diabetic NOD mice; and stimulated accumulation of p62 in NOR (p < 0.001), but not in NOD mice. We observed reduced LC3–LAMP1 colocalisation (p < 0.001) in residual beta cells of human donors with type 1 diabetes vs non-diabetic participants. We also observed reduced colocalisation of proinsulin with LAMP1 in donors with type 1 diabetes (p < 0.001). Electron microscopy also revealed accumulation of telolysosomes with nitrogen-dense rings in beta cells of autoantibody-positive donors (p = 0.002). Conclusions/interpretation We provide evidence of islet macroautophagy/crinophagy impairment in human type 1 diabetes. We also document accumulation of telolysosomes with peripheral nitrogen in beta cells of autoantibody-positive donors, demonstrating altered lysosome content that may be associated with lysosome dysfunction before clinical hyperglycaemia. Similar macroautophagy impairments are present in the NOD mouse model of type 1 diabetes. Graphical abstract

scholarly journals Pancreatic Beta Cell Autophagy is Impaired in Type 1 Diabetes

2020 ◽  
Author(s):  
Charanya Muralidharan ◽  
Abass M. Conteh ◽  
Michelle R. Marasco ◽  
Justin J. Crowder ◽  
Jeroen Kuipers ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Beta Cell ◽  
Beta Cells ◽  
Nod Mice ◽  
List Type ◽  
Tissue Sections ◽  
Human Type ◽  
Diabetes Development ◽  
Human Type 1 Diabetes

AbstractAims/hypothesisPancreatic beta cells are highly metabolic secretory cells that are subjected to exogenous damaging factors such as proinflammatory cytokines or excess glucose that can cause accumulation of damage-inducing reactive oxygen species (ROS) during the pathogenesis of diabetes. We and others have shown that beta cell autophagy can reduce ROS to protect against apoptosis both in vitro and in vivo. While impaired islet autophagy has been demonstrated in human type 2 diabetes, it is unknown if islet autophagy is perturbed in the pathogenesis of type 1 diabetes. We hypothesized that beta cell autophagy is dysfunctional in type 1 diabetes, and that there is a progressive loss during early diabetes development.MethodsMouse pancreata were collected from chloroquine injected and non-injected NOR, nondiabetic NOD, and diabetic NOD mice. Age and BMI-matched pancreas tissue sections from human organ donors (n=34) were obtained from the Network for Pancreatic Organ Donors with Diabetes (nPOD). To assess autophagic flux, we injected the mice with chloroquine to inhibit the final stages of autophagy. We analyzed tissues for markers of autophagy via immunofluorescence analysis. Tissue sections were stained with antibodies against proinsulin or insulin (beta cell markers), LC3A/B (autophagosome marker), Lamp1 (lysosome marker), and p62 (autophagy adaptor protein and marker for autophagic flux). Images were collected on a scanning laser confocal microscope then analyzed with CellProfiler and ImageJ. Secondary lysosomes and telolysosomes (formerly called lipofuscin bodies, residual bodies or tertiary lysosomes) were analyzed in electron micrographs of pancreatic tissue sections from human organ donors (nPOD; n=12) deposited in www.nanotomy.org/OA/nPOD. Energy Dispersive X-ray (EDX) analysis was also performed on these tissues to analyze distribution of elements such as nitrogen, phosphorus, and osmium in secondary lysosomes and telolysosomes of nondiabetic and autoantibody positive donor tissues (n=5).ResultsWe observed increased autophagosome numbers in islets of diabetic NOD mice (p=0.0077) and increased p62 in islets of both nondiabetic and diabetic NOD mice (p<0.0001 in both cases) when compared to NOR mice. There was also a significant reduction in autophagosome:lysosome colocalization in islets of diabetic NOD mice compared to both nondiabetic NOD mice (p=0.0004) and NOR mice (p=0.0003). Chloroquine infusions elicited accumulation of autophagosomes in the islets of NOR (p=0.0029) and nondiabetic NOD mice (p<0.0001), but not in the islets of diabetic NOD mice. Chloroquine also stimulated an accumulation of the autophagy adaptor protein p62 in the islets of NOR mice (p<0.001), however this was not observed in NOD mice (regardless of diabetes status). In the human pancreata, we observed significantly reduced autophagosome:lysosome colocalization (p=0.0002) in the residual beta cells of donors with type 1 diabetes compared to nondiabetic controls. We also observed reduced colocalization of proinsulin with lysosomes in the residual beta cells of donors with type 1 diabetes compared to both nondiabetic (p<0.0001) and autoantibody positive donors (p<0.0001). Electron microscopy based analysis of human pancreas sections also revealed accumulation of telolysosomes in beta cells of autoantibody positive donors (p=0.0084), the majority of which had an nitrogen dense ring outside a phospholipid core.Conclusions/interpretationCollectively, we provide evidence of impairment in the final degradation stages of islet macroautophagy and crinophagy in human type 1 diabetes. We also document an accumulation of telolysosomes with nitrogen accumulation at their periphery in the beta cells of autoantibody positive donors. This demonstrates clear differences in the lysosome contents of autoantibody positive donors that may be associated with lysosome dysfunction prior to clinical hyperglycemia. We observe similar impairments in macroautophagy in the diabetic NOD mouse, a model of type 1 diabetes, suggesting that this mouse model can be appropriately used to study the pathogenesis of autophagy/crinophagy loss and how it relates to disease initiation and progression. Considering these data in the context of what is known regarding the cell-protective effects of islet autophagy, we suggest targeting beta cell autophagy pathways as an approach to reduce apoptosis in individuals at risk for type 1 diabetes development.Research in contextWhat is already known about this subject?Autophagy confers a cytoprotective role in the beta cell.Autophagy is reduced in type 2 diabetes.Autophagy in the context of type 1 diabetes is unexplored.What is the key question?Is autophagy reduced during the pathogenesis of human type 1 diabetes?What are the new findings?We provide evidence of reduced autophagy and crinophagy in human type 1 diabetes.These data are supported by observations of reduced autophagy in a mouse model of autoimmune diabetes.How might this impact on clinical practice in the foreseeable future?This study provides evidence that autophagy is impaired in human type 1 diabetes. Prior studies have shown that loss of autophagy in the islet is associated with increased beta cell apoptosis, therefore we propose that therapeutic targeting of autophagy pathways may reduce beta cell death in type 1 diabetes development.

scholarly journals Replacing murine insulin 1 with human insulin protects NOD mice from diabetes

2019 ◽  
Author(s):  
Colleen M. Elso ◽  
Nicholas A. Scott ◽  
Lina Mariana ◽  
Emma I. Masterman ◽  
Andrew P.R. Sutherland ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Beta Cells ◽  
Mouse Models ◽  
Human Insulin ◽  
Murine Model ◽  
Pancreatic Beta Cells ◽  
Autoimmune Diabetes ◽  
Nod Mice ◽  
Human Type 1 Diabetes

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.

scholarly journals NADPH Oxidase-Derived Overproduction of Reactive Oxygen Species Impairs Postischemic Neovascularization in Mice with Type 1 Diabetes

2006 ◽  
Vol 169 (2) ◽  
pp. 719-728 ◽  
Author(s):  
Téni G Ebrahimian ◽  
Christophe Heymes ◽  
Dong You ◽  
Olivier Blanc-Brude ◽  
Barend Mees ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Type 1 Diabetes ◽  
Nadph Oxidase ◽  
Reactive Oxygen ◽  
Oxygen Species

scholarly journals Human gut microbiota transferred to germ-free NOD mice modulate the progression towards type 1 diabetes regardless of the pace of beta cell function loss in the donor

Diabetologia ◽  
2019 ◽  
Vol 62 (7) ◽  
pp. 1291-1296 ◽  
Author(s):  
Vit Neuman ◽  
Ondrej Cinek ◽  
David P. Funda ◽  
Tomas Hudcovic ◽  
Jaroslav Golias ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Gut Microbiota ◽  
Beta Cell ◽  
Beta Cell Function ◽  
Cell Function ◽  
Nod Mice ◽  
Human Gut ◽  
Germ Free ◽  
Function Loss

Beta-cell markers and autoantigen expression by a human insulinoma cell line: similarities to native beta cells

1996 ◽  
Vol 150 (1) ◽  
pp. 113-120 ◽  
Author(s):  
M G Cavallo ◽  
F Dotta ◽  
L Monetini ◽  
S Dionisi ◽  
M Previti ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Monoclonal Antibodies ◽  
Beta Cell ◽  
Cell Line ◽  
Beta Cells ◽  
Cell Markers ◽  
Insulinoma Cell ◽  
Insulinoma Cell Line ◽  
Human Insulinoma

Abstract In the present study we have evaluated the expression of different beta-cell markers, islet molecules and autoantigens relevant in diabetes autoimmunity by a human insulinoma cell line (CM) in order to define its similarities with native beta cells and to discover whether it could be considered as a model for studies on immunological aspects of Type 1 diabetes. First, the positivity of the CM cell line for known markers of neuroendocrine derivation was determined by means of immunocytochemical analysis using different anti-islet monoclonal antibodies including A2B5 and 3G5 reacting with islet gangliosides, and HISL19 binding to an islet glycoprotein. Secondly, the expression and characteristics of glutamic acid decarboxylase (GAD) and of GM2-1 ganglioside, both known to be islet autoantigens in diabetes autoimmunity and expressed by human native beta cells, were investigated in the CM cell line. The pattern of ganglioside expression in comparison to that of native beta cells was also evaluated. Thirdly, the binding of diabetic sera to CM cells reacting with islet cytoplasmic antigens (ICA) was studied by immunohistochemistry. The results of this study showed that beta cell markers identified by anti-islet monoclonal antibodies A2B5, 3G5 and HISL-19 are expressed by CM cells; similarly, islet molecules such as GAD and GM2-1 ganglioside are present and possess similar characteristics to those found in native beta cells; the pattern of expression of other gangliosides by CM cells is also identical to human pancreatic islets; beta cell autoantigen(s) reacting with antibodies present in islet cell antibodies (ICA) positive diabetic sera identified by ICA binding are also detectable in this insulinoma cell line. We conclude that CM cells show close similarities to native beta cells with respect to the expression of neuroendocrine markers, relevant beta cell autoantigens in Type 1 diabetes (GAD, GM2-1, ICA antigen), and other gangliosides. Therefore, this insulinoma cell line may be considered as an ideal model for studies aimed at investigating autoimmune phenomena occurring in Type 1 diabetes. Journal of Endocrinology (1996) 150, 113–120

scholarly journals Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Susanne W. Bruun ◽  
Knud Josefsen ◽  
Julia T. Tanassi ◽  
Aleš Marek ◽  
Martin H. F. Pedersen ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Beta Cells ◽  
Degradation Products ◽  
Intestinal Barrier ◽  
Nod Mice ◽  
Radioactive Label ◽  
Nonobese Diabetic ◽  
Gliadin Peptide ◽  
Gliadin Peptides

Gluten promotes type 1 diabetes in nonobese diabetic (NOD) mice and likely also in humans. In NOD mice and in non-diabetes-prone mice, it induces inflammation in the pancreatic lymph nodes, suggesting that gluten can initiate inflammation locally. Further, gliadin fragments stimulate insulin secretion from beta cells directly. We hypothesized that gluten fragments may cross the intestinal barrier to be distributed to organs other than the gut. If present in pancreas, gliadin could interact directly with the immune system and the beta cells to initiate diabetes development. We orally and intravenously administered 33-mer and 19-mer gliadin peptide to NOD, BALB/c, and C57BL/6 mice and found that the peptides readily crossed the intestinal barrier in all strains. Several degradation products were found in the pancreas by mass spectroscopy. Notably, the exocrine pancreas incorporated large amounts of radioactive label shortly after administration of the peptides. The study demonstrates that, even in normal animals, large gliadin fragments can reach the pancreas. If applicable to humans, the increased gut permeability in prediabetes and type 1 diabetes patients could expose beta cells directly to gliadin fragments. Here they could initiate inflammation and induce beta cell stress and thus contribute to the development of type 1 diabetes.

scholarly journals Nox4-derived reactive oxygen species mediate cardiomyocyte injury in early type 1 diabetes

2012 ◽  
Vol 302 (3) ◽  
pp. C597-C604 ◽  
Author(s):  
Rita M. Maalouf ◽  
Assaad A. Eid ◽  
Yves C. Gorin ◽  
Karen Block ◽  
Gladys Patricia Escobar ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Type 1 Diabetes ◽  
Molecular Markers ◽  
Nadph Oxidase ◽  
Diabetic Cardiomyopathy ◽  
Oxidase Activity ◽  
Diabetic Rats ◽  
Oxygen Species ◽  
Nadph Oxidase Activity

Oxidative stress contributes to diabetic cardiomyopathy. This study explored the role of the NADPH oxidase Nox4 as a source of reactive oxygen species (ROS) involved in the development of diabetic cardiomyopathy. Phosphorothioated antisense (AS) or sense (S) oligonucleotides for Nox4 were administered for 2 wk to rats made diabetic by streptozotocin. NADPH oxidase activity, ROS generation, and the expression of Nox4, but Nox1 or Nox2, were increased in left ventricular tissue of the diabetic rats. Expression of molecular markers of hypertrophy and myofibrosis including fibronectin, collagen, α-smooth muscle actin, and β-myosin heavy chain were also increased. These parameters were attenuated by the administration of AS but not S Nox4. Moreover, the impairment of contractility observed in diabetic rats was prevented in AS- but not S-treated animals. Exposure of cultured cardiac myocytes to 25 mM glucose [high glucose (HG)] increased NADPH oxidase activity, the expression of Nox4, and molecular markers of cardiac injury. These effects of HG were prevented in cells infected with adenoviral vector containing a dominant negative form of Nox4. This study provides strong evidence that Nox4 is an important source of ROS in the left ventricle and that Nox4-derived ROS contribute to cardiomyopathy at early stages of type 1 diabetes.

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