scholarly journals Inhibition of the Keap1/Nrf2 Signaling Pathway Significantly Promotes the Progression of Type 1 Diabetes Mellitus

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Yanmei Lou ◽  
Muyan Kong ◽  
Leyan Li ◽  
Yu Hu ◽  
Wenjun Zhai ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathway ◽  
Cell Damage ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Min6 Cells ◽  
Nrf2 Signaling Pathway

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by insulin deficiency due to pancreatic β-cell damage and leads to hyperglycemia. The precise molecular mechanisms of the etiology of T1DM are not completely understood. Oxidative stress and the antioxidant status of pancreatic β-cells play a vital role in the pathogenesis and progression of T1DM. The Keap1/Nrf2 signaling pathway plays a critical role in cellular resistance to oxidative stress. This study is aimed at investigating the role of the Keap1/Nrf2 signaling pathway in the progression of T1DM. An alloxan- (ALX-) stimulated T1DM animal model in wild-type (WT) and Nrf2 knockout (Nrf2-/-) C57BL/6J mice and a mouse pancreatic β-cell line (MIN6) were established. Compared with the tolerant (ALX exposure, nondiabetic) WT mice, the sensitive (ALX exposure, diabetic) WT mice exhibited higher blood glucose levels and lower plasma insulin levels. The Keap1/Nrf2 signaling pathway was significantly inhibited in the sensitive WT mice, which was reflected by overexpression of Keap1 and low expression of Nrf2, accompanied by a marked decrease in the expression of the antioxidative enzymes. Compared with WT mice, the Nrf2-/- mice had an increased incidence of T1DM and exhibited more severe pancreatic β-cell damage. The results of in vitro experiments showed that ALX significantly inhibited the viability and proliferation and promoted the apoptosis of MIN6 cells. ALX also markedly increased intracellular ROS production and caused DNA damage in MIN6 cells. In addition, the Keap1/Nrf2 signaling pathway was significantly inhibited in the damaged MIN6 cells. Moreover, Nrf2 silencing by transfection with Nrf2 siRNA markedly exacerbated ALX-induced MIN6 cell injury. Conclusively, this study demonstrates that inhibition of the Keap1/Nrf2 signaling pathway could significantly promote the incidence of T1DM. This study indicates that activation of Keap1/Nrf2 signaling in pancreatic β-cells may be a useful pharmacological strategy for the clinical prevention and treatment of T1DM.

scholarly journals Nonlinear Analysis for a Type-1 Diabetes Model with Focus on T-Cells and Pancreatic β-Cells Behavior

2020 ◽  
Vol 25 (2) ◽  
pp. 23
Author(s):  
Diana Gamboa ◽  
Carlos E. Vázquez ◽  
Paul J. Campos
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Cell Population ◽  
Closed Loop ◽  
Pancreatic Β Cell ◽  
Activated Macrophages ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells

Type-1 diabetes mellitus (T1DM) is an autoimmune disease that has an impact on mortality due to the destruction of insulin-producing pancreatic β -cells in the islets of Langerhans. Over the past few years, the interest in analyzing this type of disease, either in a biological or mathematical sense, has relied on the search for a treatment that guarantees full control of glucose levels. Mathematical models inspired by natural phenomena, are proposed under the prey–predator scheme. T1DM fits in this scheme due to the complicated relationship between pancreatic β -cell population growth and leukocyte population growth via the immune response. In this scenario, β -cells represent the prey, and leukocytes the predator. This paper studies the global dynamics of T1DM reported by Magombedze et al. in 2010. This model describes the interaction of resting macrophages, activated macrophages, antigen cells, autolytic T-cells, and β -cells. Therefore, the localization of compact invariant sets is applied to provide a bounded positive invariant domain in which one can ensure that once the dynamics of the T1DM enter into this domain, they will remain bounded with a maximum and minimum value. Furthermore, we analyzed this model in a closed-loop scenario based on nonlinear control theory, and proposed bases for possible control inputs, complementing the model with them. These entries are based on the existing relationship between cell–cell interaction and the role that they play in the unchaining of a diabetic condition. The closed-loop analysis aims to give a deeper understanding of the impact of autolytic T-cells and the nature of the β -cell population interaction with the innate immune system response. This analysis strengthens the proposal, providing a system free of this illness—that is, a condition wherein the pancreatic β -cell population holds and there are no antigen cells labeled by the activated macrophages.

scholarly journals Potential Mimicry of Viral and Pancreatic β Cell Antigens Through Non-Spliced and cis-Spliced Zwitter Epitope Candidates in Type 1 Diabetes

2021 ◽  
Vol 12 ◽  
Author(s):  
Michele Mishto ◽  
Artem Mansurkhodzhaev ◽  
Teresa Rodriguez-Calvo ◽  
Juliane Liepe
Keyword(s):  
Type 1 Diabetes ◽  
T Cell ◽  
Viral Infections ◽  
Hla Class I ◽  
Class I ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells

Increasing evidence suggests that post-translational peptide splicing can play a role in the immune response under pathological conditions. This seems to be particularly relevant in Type 1 Diabetes (T1D) since post-translationally spliced epitopes derived from T1D-associated antigens have been identified among those peptides bound to Human Leucocyte Antigen (HLA) class I and II complexes. Their immunogenicity has been confirmed through CD4+ and CD8+ T cell-mediated responses in T1D patients. Spliced peptides theoretically have a large sequence variability. This might increase the frequency of viral-human zwitter peptides, i.e. peptides that share a complete sequence homology irrespective of whether they originate from human or viral antigens, thereby impinging upon the discrimination between self and non-self antigens by T cells. This might increase the risk of autoimmune responses triggered by viral infections. Since enteroviruses and other viral infections have historically been associated with T1D, we investigated whether cis-spliced peptides derived from selected viruses might be able to trigger CD8+ T cell-mediated autoimmunity. We computed in silico viral-human non-spliced and cis-spliced zwitter epitope candidates, and prioritized peptide candidates based on: (i) their binding affinity to HLA class I complexes, (ii) human pancreatic β cell and medullary thymic epithelial cell (mTEC) antigens’ mRNA expression, (iii) antigen association with T1D, and (iv) potential hotspot regions in those antigens. Neglecting potential T cell receptor (TCR) degeneracy, no viral-human zwitter non-spliced peptide was found to be an optimal candidate to trigger a virus-induced CD8+ T cell response against human pancreatic β cells. Conversely, we identified some zwitter peptide candidates, which may be produced by proteasome-catalyzed peptide splicing, and might increase the likelihood of pancreatic β cells recognition by virus-specific CD8+ T cell clones, therefore promoting β cell destruction in the context of viral infections.

scholarly journals CRISPR/Cas9-Mediated α-ENaC Knockout in a Murine Pancreatic β-Cell Line

2021 ◽  
Vol 12 ◽  
Author(s):  
Xue Zhang ◽  
Lihua Zhao ◽  
Runbing Jin ◽  
Min Li ◽  
Mei-Shuang Li ◽  
...  
Keyword(s):  
Cell Line ◽  
Gene Knockout ◽  
Pancreatic Tissue ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Min6 Cells ◽  
Insulin Synthesis ◽  
Guide Rna

Many ion channels participate in controlling insulin synthesis and secretion of pancreatic β-cells. Epithelial sodium channel (ENaC) expressed in human pancreatic tissue, but the biological role of ENaC in pancreatic β-cells is still unclear. Here, we applied the CRISPR/Cas9 gene editing technique to knockout α-ENaC gene in a murine pancreatic β-cell line (MIN6 cell). Four single-guide RNA (sgRNA) sites were designed for the exons of α-ENaC. The sgRNA1 and sgRNA3 with the higher activity were constructed and co-transfected into MIN6 cells. Through processing a series of experiment flow included drug screening, cloning, and sequencing, the α-ENaC gene-knockout (α-ENaC−/−) in MIN6 cells were obtained. Compared with the wild-type MIN6 cells, the cell viability and insulin content were significantly increased in α-ENaC−/− MIN6 cells. Therefore, α-ENaC−/− MIN6 cells generated by CRISPR/Cas9 technology added an effective tool to study the biological function of α-ENaC in pancreatic β-cells.

scholarly journals mTORC in β cells: more Than Only Recognizing Comestibles

2017 ◽  
Vol 216 (7) ◽  
pp. 1883-1885 ◽  
Author(s):  
Kathrin Maedler ◽  
Amin Ardestani
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Dysfunction ◽  
Cell Survival ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Cell Biol

The pathways regulating pancreatic β cell survival in diabetes are poorly understood. Here, Chau et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201701085) demonstrate that mTOR regulates the apoptotic machinery through binding to the ChREBP–Mlx complex to suppress TXNIP, thereby protecting pancreatic β cells in the diabetic setting by inhibiting oxidative stress and mitochondrial dysfunction.

Cyanidin-3-rutinoside protects INS-1 pancreatic β cells against high glucose-induced glucotoxicity by apoptosis

2018 ◽  
Vol 73 (7-8) ◽  
pp. 281-289 ◽  
Author(s):  
Kung-Ha Choi ◽  
Mi Hwa Park ◽  
Hyun Ah Lee ◽  
Ji-Sook Han
Keyword(s):  
Cell Death ◽  
High Glucose ◽  
Cell Damage ◽  
Therapeutic Effects ◽  
Dependent Manner ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Induced Apoptosis

Abstract Exposure to high levels of glucose may cause glucotoxicity, leading to pancreatic β cell dysfunction, including cell apoptosis and impaired glucose-stimulated insulin secretion. The aim of this study was to explore the effect of cyanidin-3-rutinoside (C3R), a derivative of anthocyanin, on glucotoxicity-induced apoptosis in INS-1 pancreatic β cells. Glucose (30 mM) treatment induced INS-1 pancreatic β cell death, but glucotoxicity and apoptosis significantly decreased in cells treated with 50 μM C3R compared to that observed in 30 mM glucose-treated cells. Furthermore, hyperglycemia increased intracellular reactive oxygen species (ROS), lipid peroxidation, and nitric oxide (NO) levels, while C3R treatment reduced these in a dose-dependent manner. C3R also increased the activity of antioxidant enzymes, markedly reduced the expression of pro-apoptotic proteins (such as Bax, cytochrome c, caspase 9 and caspase 3), and increased the expression of the anti-apoptotic protein, Bcl-2, in hyperglycemia-exposed cells. Finally, cell death was examined using annexin V/propidium iodide staining, which revealed that C3R significantly reduced high glucose-induced apoptosis. In conclusion, C3R may have therapeutic effects against hyperglycemia-induced β cell damage in diabetes.

Protective functions of peroxiredoxin-1 against cytokine-induced MIN6 pancreatic β-cell line death

2013 ◽  
Vol 91 (12) ◽  
pp. 1037-1043 ◽  
Author(s):  
Yun-Jung Lee ◽  
Dong Sup Song ◽  
Jong-Sun Yoo ◽  
Kyeong Eun Hyung ◽  
Mi Ji Lee ◽  
...  
Keyword(s):  
Antioxidant Enzyme ◽  
Cell Line ◽  
Nuclear Translocation ◽  
Inos Expression ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Min6 Cells ◽  
Apoptotic Gene

Pancreatic β-cells play a crucial role in glucose homeostasis, and the failure of these cells to function results in the development of type 1 diabetes (T1D). The MIN6 cell line, which closely resembles pancreatic β-cells, was used to unravel the relationship between pancreatic β-cell function and the antioxidant enzyme PRX-1. PRX-1 was knocked down in MIN6 cells using a shPRX-1 lentiviral construct, and a mixture of inflammatory cytokines was administered to challenge the MIN6 cells. Nitric oxide (NO) production and inducible NO synthase (iNOS) expression were elevated in shPRX-1 compared with the control. Also, shPRX-1 transduced cells showed higher levels of NF-κB nuclear translocation, suggesting that PRX-1 has a regulatory role in NF-κB nuclear translocation and iNOS expression. In correlation with NO levels, decreased anti-apoptotic gene Bcl-xl level and elevated pro-apoptotic gene Bim levels were observed in shPRX-1 cells compared with scramble, and cell viability decreased accordingly. A rescue experiment was performed subsequently using an iNOS inhibitor to confirm NO as the cause of cell death. Overall, the results of this study suggest possible protective roles of the antioxidant enzyme PRX-1 in the insulinoma cell line MIN6 and possibly in pancreatic β-cells under T1D conditions.

scholarly journals SARS-CoV-2 Infection and Pancreatic β Cell Failure

Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 22
Author(s):  
Keiichiro Mine ◽  
Seiho Nagafuchi ◽  
Hitoe Mori ◽  
Hirokazu Takahashi ◽  
Keizo Anzai
Keyword(s):  
Diabetes Mellitus ◽  
Cell Damage ◽  
Study Groups ◽  
Multiple Organ ◽  
Multiple Organ Dysfunction ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Potential Association

SARS-CoV-2 infection primarily causes pulmonary symptoms; however, accumulating reports indicate that some patients with COVID-19 have multiple organ dysfunction or failure. Although diabetes is considered a risk factor for severe COVID-19, SARS-CoV-2 infection may also be a causal factor for diabetes mellitus in patients with COVID-19. According to the research reviewed in this paper, the pancreas and pancreatic β cells appear to be targets of SARS-CoV-2 and are damaged by direct or indirect effects of the infection. However, controversial results have been reported between study groups, mainly due to the limited number of cases with diabetes precipitated by COVID-19. In this review, we comprehensively discuss the published findings on the potential association between SARS-CoV-2 infection or COVID-19 and pancreatic β-cell damage leading to diabetes onset. These findings will further contribute to our understanding of the pathogenesis of diabetes mellitus.

scholarly journals Soursop (Annona Muricata) Leaf Water Extract (SLWE) Prevent Pancreatic Β-Cell Damage in Male Wistar Rats Induced By High Fat and High Fructose (HFHF) Diet

2019 ◽  
Vol 4 (6) ◽  
Keyword(s):  
Treatment Group ◽  
Wistar Rats ◽  
Cell Damage ◽  
Water Extract ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Glucose Levels ◽  
Male Wistar Rats

Background: A high-fructose high fat (HFHF) diet induces dyslipidemia, which can interfere with pancreatic function. Soursop leaf (Annona muricata) water extract (SLWE) has ant hyperlipidemia and antioxidants activity. This research aims to assess the activity of SLWE in preventing pancreatic β-cell damage in male Wistar rats induced by the HFHF diet. Method: This study is a post test group control only research design. Twenty-five wistar rats aged 10-12 weeks, weighing 175- 200 g, were randomly divided into five study groups, namely the normal group (N) laboratory standard diet, the positive group (P) HFHF diet, and the treatment group 1 (T1) HFHF diet+SLWE dose 100mg/kgbw, treatment group 2 (T2) HFHF diet+SLWE dose 200mg/kgbw, and treatment group 3 (T3) HFHF diet+SLWE dose 400mg/kgbw. Diet is given for ten weeks. Measurement of fasting blood glucose levels were taken from the tail using a rapid test conducted at the beginning and end of the study. At the end of the study, the rates were sacrificed under anesthesia. The rats pancreatic organs were surgically removed and blood was taken from the ventricular puncture. Pancreatic organs are used to measure the percentage of pancreatic β cells, which expressed FoxO1 protein, by flow cytometry method, and the average area of pancreatic β cells by immunohistochemistry. Blood is centrifuged to obtain blood plasma, which is used to measure insulin levels. Data were analyzed using One Way Anova and Kruskal Wallis with a significance of p <0.05. Result: SLWE did not cause changes in blood glucose levels, but the administration of SLWE at a doses of 200mg/kgBB tended to increase insulin levels (p> 0.05), decreased percentage number of β-cells expressing FoxO1, and decreased the average area of pancreatic β cells compared to P group (p <0.05). Conclusion: SLWE can prevent pancreatic β-cell damage by increase insulin secretion without causing pancreatic β-cell proliferation.

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