Elucidation of Molecular Mechanisms of Streptozotocin-Induced Oxidative Stress, Apoptosis, and Mitochondrial Dysfunction in Rin-5F Pancreatic β-Cells

Streptozotocin is a pancreatic beta-cell-specific cytotoxin and is widely used to induce experimental type 1 diabetes in rodent models. The precise molecular mechanism of STZ cytotoxicity is however not clear. Studies have suggested that STZ is preferably absorbed by insulin-secreting β-cells and induces cytotoxicity by producing reactive oxygen species/reactive nitrogen species (ROS/RNS). In the present study, we have investigated the mechanism of cytotoxicity of STZ in insulin-secreting pancreatic cancer cells (Rin-5F) at different doses and time intervals. Cell viability, apoptosis, oxidative stress, and mitochondrial bioenergetics were studied. Our results showed that STZ induces alterations in glutathione homeostasis and inhibited the activities of the respiratory enzymes, resulting in inhibition of ATP synthesis. Apoptosis was observed in a dose- and time-dependent manner. Western blot analysis has also confirmed altered expression of oxidative stress markers (e.g., NOS and Nrf2), cell signaling kinases, apoptotic protein-like caspase-3, PARP, and mitochondrial specific proteins. These results suggest that STZ-induced cytotoxicity in pancreatic cells is mediated by an increase in oxidative stress, alterations in cellular metabolism, and mitochondrial dysfunction. This study may be significant in better understanding the mechanism of STZ-induced β-cell toxicity/resistance and the etiology of type 1 diabetes induction.

Download Full-text

Oxidative stress and mitochondrial dysfunction associated with peripheral neuropathy in type 1 diabetes

Antioxidants and Redox Signaling ◽

10.1089/ars.2021.0152 ◽

2021 ◽

Author(s):

Eftekhar Eftekharpour ◽

Paul Fernyhough

Keyword(s):

Oxidative Stress ◽

Type 1 Diabetes ◽

Peripheral Neuropathy ◽

Mitochondrial Dysfunction

Download Full-text

Metallothionein expression in slow- vs. fast-twitch muscle fibers following 4 weeks of streptozotocin-induced type 1 diabetes

FACETS ◽

10.1139/facets-2017-0058 ◽

2018 ◽

Vol 3 (1) ◽

pp. 315-325 ◽

Cited By ~ 1

Author(s):

Pamela Mondragon ◽

Andreas Bergdahl

Keyword(s):

Oxidative Stress ◽

Type 1 Diabetes ◽

Molecular Mechanisms ◽

Protein Carbonyl ◽

Glucose Levels ◽

Significant Difference ◽

Streptozotocin Induced Diabetes ◽

Carbonyl Formation ◽

Fast Twitch

Type 1 diabetes (T1DM) is known to cause an increase in reactive oxygen species (ROS) and elevated intracellular glucose levels. We investigated the metallothionein I and II (MT I+II) antioxidants expression in soleus (mainly slow-twitch) and plantaris (predominantly fast-twitch) skeletal muscle using a rodent model of streptozotocin-induced diabetes. The presence of oxidative stress was confirmed by the detection of increased levels of protein carbonyl formation in the diabetic tissues. DAB (3,3′-diaminobenzidine) immunostaining and Western blotting analyses demonstrated that MT I+II expression was significantly upregulated in the diabetic soleus and plantaris muscle tissues compared with their respective controls. Moreover, no significant difference was detected between the plantaris and soleus controls or between the plantaris and soleus diabetic tissues. These findings suggest that there is an increase in MT protein expression in the soleus and plantaris muscles associated with the induction of T1DM. A better understanding of the molecular mechanisms that allow MT to prevent the oxidative stress associated with diabetes could lead to a novel therapeutic strategy for this chronic disease and its associated complications.

Download Full-text

Shikonin exerts antitumor activity by causing mitochondrial dysfunction in hepatocellular carcinoma through PKM2–AMPK–PGC1α signaling pathway

Biochemistry and Cell Biology ◽

10.1139/bcb-2018-0310 ◽

2019 ◽

Vol 97 (4) ◽

pp. 397-405 ◽

Cited By ~ 8

Author(s):

Bing Liu ◽

Jiangbo Jin ◽

Ziyu Zhang ◽

Li Zuo ◽

Meixiu Jiang ◽

...

Keyword(s):

Oxidative Stress ◽

Hepatocellular Carcinoma ◽

Antitumor Activity ◽

Mitochondrial Dysfunction ◽

Signaling Pathway ◽

Mitochondrial Function ◽

Molecular Mechanisms ◽

Tricarboxylic Acid Cycle ◽

Dependent Manner ◽

Promising Therapeutic Approach

Shikonin, a naphthoquinone derivative isolated from the root of Lithospermum erythrorhizon, exhibits broad-spectrum antitumor activity via different molecular mechanisms. In this study, we investigated the effect of shikonin on mitochondrial dysfunction in hepatocellular carcinoma (HCC). Our results showed that shikonin inhibited the proliferation, migration, and invasiveness of HCCLM3 cells, and promoted cell apoptosis in a dose-dependent manner. More importantly, shikonin affected mitochondrial function by disrupting mitochondrial membrane potential and oxidative stress (OS) status. Furthermore, shikonin decreased the oxygen consumption rate of HCCLM3 cells, as well as the levels of ATP and metabolites involved in the tricarboxylic acid cycle (TCA cycle). We also investigated the molecular mechanisms underlying the regulation of mitochondrial function by shikonin as an inhibitor of PKM2. Shikonin decreased the expression of PKM2 in the mitochondria and affected other metabolic pathways (AMPK and PGC1α pathways), which aggravated the oxidative stress and nutrient deficiency. Our results indicate a novel role of shikonin in triggering mitochondria dysfunction via the PKM2–AMPK–PGC1α signaling pathway and provide a promising therapeutic approach for the treatment of HCC.

Download Full-text

Blockade of Cyclophilin D Attenuates Oxidative Stress-Induced Cell Death in Human Dental Pulp Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/1729013 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Shengbin Huang ◽

Bingbing Zheng ◽

Xing Jin ◽

Qihao Yu ◽

Xiaorong Zhang ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Mitochondrial Dysfunction ◽

Dental Pulp ◽

Molecular Mechanisms ◽

Mitochondrial Permeability Transition ◽

Dependent Manner ◽

Dental Pulp Cells ◽

Cyclophilin D ◽

Pulp Cells

Pathological stimuli, such as bacterial activity, dental bleaching, and nonpolymerized resin monomers, can cause death of dental pulp cells (DPCs) through oxidative stress- (OS-) induced mitochondrial dysfunction. However, the crucial molecular mechanisms that mediate such a phenomenon remain largely unknown. OS is characterized by the overproduction of reactive oxygen species (ROS), e.g., H2O2, O2−, and ⋅OH. Mitochondria are a major source of ROS and the principal attack target of ROS. Cyclophilin D (CypD), as the only crucial protein for mitochondrial permeability transition pore (mPTP) induction, facilitates the opening of mPTP and causes mitochondrial dysfunction, leading to cell death. In the present study, we hypothesized that CypD-mediated mitochondrial molecular pathways were closely involved in the process of OS-induced death of human DPCs (HDPCs). We tested the phenotypic and molecular changes of HDPCs in a well-established OS model—H2O2 treatment. We showed that H2O2 dramatically reduced the viability and increased the death of HDPCs in a time- and dose-dependent manner by performing MTT, flow cytometry, and TUNEL assays and quantifying the expression changes of Bax and Bcl-2 proteins. H2O2 also induced mitochondrial dysfunction, as reflected by the increased mitochondrial ROS, reduced ATP production, and activation of mPTP (decreased mitochondrial membrane potential and enhanced intracellular Ca2+ level). An antioxidant (N-acetyl-L-cysteine) effectively preserved mitochondrial function and significantly attenuated H2O2-induced cytotoxicity and death. Moreover, H2O2 treatment markedly upregulated the CypD protein level in HDPCs. Notably, genetic or pharmacological blockade of CypD significantly attenuated H2O2-induced mitochondrial dysfunction and cell death. These findings provided novel insights into the role of a CypD-dependent mitochondrial pathway in the H2O2-induced death in HDPCs, indicating that CypD may be a potential therapeutic target to prevent OS-mediated injury in dental pulp.

Download Full-text

The Parkinson’s Disease-Associated Protein DJ-1 Protects Dictyostelium Cells from AMPK-Dependent Outcomes of Oxidative Stress

Cells ◽

10.3390/cells10081874 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1874

Author(s):

Suwei Chen ◽

Sarah J. Annesley ◽

Rasha A. F. Jasim ◽

Paul R. Fisher

Keyword(s):

Oxidative Stress ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Mitochondrial Dysfunction ◽

Mitochondrial Respiration ◽

Cysteine Residue ◽

Reduced Form ◽

Dependent Manner ◽

Loss Of Function ◽

Cellular Pathology

Mitochondrial dysfunction has been implicated in the pathology of Parkinson’s disease (PD). In Dictyostelium discoideum, strains with mitochondrial dysfunction present consistent, AMPK-dependent phenotypes. This provides an opportunity to investigate if the loss of function of specific PD-associated genes produces cellular pathology by causing mitochondrial dysfunction with AMPK-mediated consequences. DJ-1 is a PD-associated, cytosolic protein with a conserved oxidizable cysteine residue that is important for the protein’s ability to protect cells from the pathological consequences of oxidative stress. Dictyostelium DJ-1 (encoded by the gene deeJ) is located in the cytosol from where it indirectly inhibits mitochondrial respiration and also exerts a positive, nonmitochondrial role in endocytosis (particularly phagocytosis). Its loss in unstressed cells impairs endocytosis and causes correspondingly slower growth, while also stimulating mitochondrial respiration. We report here that oxidative stress in Dictyostelium cells inhibits mitochondrial respiration and impairs phagocytosis in an AMPK-dependent manner. This adds to the separate impairment of phagocytosis caused by DJ-1 knockdown. Oxidative stress also combines with DJ-1 loss in an AMPK-dependent manner to impair or exacerbate defects in phototaxis, morphogenesis and growth. It thereby phenocopies mitochondrial dysfunction. These results support a model in which the oxidized but not the reduced form of DJ-1 inhibits AMPK in the cytosol, thereby protecting cells from the adverse consequences of oxidative stress, mitochondrial dysfunction and the resulting AMPK hyperactivity.

Download Full-text

Prevalence of autoantibodies in type 1 diabetes mellitus pediatrics in Mazandaran, North of Iran

Journal of Pediatric Endocrinology and Metabolism ◽

10.1515/jpem-2019-0396 ◽

2020 ◽

Vol 33 (10) ◽

pp. 1299-1305

Author(s):

Daniel Zamanfar ◽

Mohsen Aarabi ◽

Monireh Amini ◽

Mahila Monajati

Keyword(s):

Diabetes Mellitus ◽

Type 1 Diabetes ◽

Serum Level ◽

Type 1 Diabetes Mellitus ◽

Children And Adolescents ◽

Statistical Significance ◽

Pancreatic Beta Cell ◽

Eligible Patient ◽

Diabetes Diagnosis

AbstractObjectivesType 1 diabetes is an autoimmune disease. Its most important immunologic markers are pancreatic beta-cell autoantibodies. This study aimed to determine diabetes mellitus antibodies frequency among children and adolescents with type 1 diabetes.MethodsThis descriptive study evaluated the frequency of four diabetes autoantibodies (glutamic acid decarboxylase 65 autoantibodies [GADA], islet cell autoantibodies [ICA], insulin autoantibodies [IAA], tyrosine phosphatase–like insulinoma antigen-2 antibodies [IA-2A]) and their serum level in children and adolescents diagnosed with type 1 diabetes mellitus at the diabetes department of Bou-Ali-Sina Hospital and Baghban Clinic, Sari, Iran, from March 2012 to March 2018. The relationship between the level of different antibodies and age, gender, and diabetes duration were determined. A two-sided p value less than 0.05 indicated statistical significance.ResultsOne hundred forty-two eligible patient records were screened. The average age at diabetes diagnosis was 4.2 ± 4.4 years. The median duration of diabetes was 34.0 (12.7–69.7) months. 53.5% of patients were female, and 81.7% of them had at least one positive autoantibody, and ICA in 66.2%, GADA in 56.3%, IA-2A in 40.1%, and IAA in 21.8% were positive. The type of the autoantibodies and their serum level was similar between females and males but there was a higher rate of positive autoantibodies in females. The level of IA-2A and ICA were in positive and weak correlation with age at diagnosis.ConclusionsMore than 80% of pediatric and adolescent patients with type 1 diabetes were autoantibody-positive. ICA and GADA were the most frequently detected autoantibodies. The presence of antibodies was significantly higher in females.

Download Full-text

Continuous subcutaneous insulin infusion alters microRNA expression and glycaemic variability in children with type 1 diabetes

Scientific Reports ◽

10.1038/s41598-021-95824-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Emma S. Scott ◽

Andrzej S. Januszewski ◽

Luke M. Carroll ◽

Gregory R. Fulcher ◽

Mugdha V. Joglekar ◽

...

Keyword(s):

Type 1 Diabetes ◽

Continuous Subcutaneous Insulin Infusion ◽

Insulin Infusion ◽

Diabetes Diagnosis ◽

Subcutaneous Insulin ◽

Glycaemic Variability ◽

Altered Expression ◽

C Peptide

AbstractTo determine whether continuous subcutaneous insulin infusion (CSII) vs. multiple daily injections (MDI) therapy from near-diagnosis of type 1 diabetes is associated with reduced glycaemic variability (GV) and altered microRNA (miRNAs) expression. Adolescents (74% male) within 3-months of diabetes diagnosis (n = 27) were randomized to CSII (n = 12) or MDI. HbA1c, 1-5-Anhydroglucitol (1,5-AG), high sensitivity C-peptide and a custom TaqMan qPCR panel of 52 miRNAs were measured at baseline and follow-up (median (LQ-UQ); 535 (519–563) days). There were no significant differences between groups in baseline or follow-up HbA1c or C-peptide, nor baseline miRNAs. Mean ± SD 1,5-AG improved with CSII vs. MDI (3.1 ± 4.1 vs. − 2.2 ± − 7.0 mg/ml respectively, P = 0.029). On follow-up 11 miRNAs associated with diabetes vascular complications had altered expression in CSII-users. Early CSII vs. MDI use is associated with lower GV and less adverse vascular-related miRNAs. Relationships with future complications are of interest.

Download Full-text

Coaggregation of Asthma and Type 1 Diabetes in Children: A Narrative Review

International Journal of Molecular Sciences ◽

10.3390/ijms22115757 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5757

Author(s):

Laura Sgrazzutti ◽

Francesco Sansone ◽

Marina Attanasi ◽

Sabrina Di Pillo ◽

Francesco Chiarelli

Keyword(s):

Diabetes Mellitus ◽

Type 1 Diabetes ◽

Molecular Mechanisms ◽

Narrative Review ◽

T Helper ◽

Children With Asthma ◽

Potential Link ◽

Th 1 ◽

Th1 And Th2

Asthma and type 1 diabetes mellitus (T1DM) are two of the most frequent chronic diseases in children, representing a model of the atopic and autoimmune diseases respectively. These two groups of disorders are mediated by different immunological pathways, T helper (Th)1 for diabetes and Th2 for asthma. For many years, these two groups were thought to be mutually exclusive according to the Th1/Th2 paradigm. In children, the incidence of both diseases is steadily increasing worldwide. In this narrative review, we report the evidence of the potential link between asthma and T1DM in childhood. We discuss which molecular mechanisms could be involved in the link between asthma and T1DM, such as genetic predisposition, cytokine patterns, and environmental influences. Cytokine profile of children with asthma and T1DM shows an activation of both Th1 and Th2 pathways, suggesting a complex genetic-epigenetic interaction. In conclusion, in children, the potential link between asthma and T1DM needs further investigation to improve the diagnostic and therapeutic approach to these patients. The aim of this review is to invite the pediatricians to consider the potential copresence of these two disorders in clinical practice.

Download Full-text