Fetuin‐A excess expression  amplifies lipid induced apoptosis and β‐cell damage

Author(s):  
Alpana Mukhuty ◽  
Chandrani Fouzder ◽  
Rakesh Kundu
2018 ◽  
Vol 73 (7-8) ◽  
pp. 281-289 ◽  
Author(s):  
Kung-Ha Choi ◽  
Mi Hwa Park ◽  
Hyun Ah Lee ◽  
Ji-Sook Han

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.


2002 ◽  
Vol 11 (3) ◽  
pp. 141-148 ◽  
Author(s):  
Shahida Shahana ◽  
Caroline Kampf ◽  
Godfried M. Roomans

Background: Allergic asthma is associated with an increased number of eosinophils in the airway wall. Eosinophils secrete cationic proteins, particularly major basic protein (MBP).Aim: To investigate the effect of synthetic cationic polypeptides such as poly-L-arginine, which can mimic the effect of MBP, on airway epithelial cells.Methods: Cultured airway epithelial cells were exposed to poly-L-arginine, and effects were determined by light and electron microscopy.Results: Poly-L-arginine induced apoptosis and necrosis. Transmission electron microscopy showed mitochondrial damage and changes in the nucleus. The tight junctions were damaged, as evidenced by penetration of lanthanum. Scanning electron microscopy showed a damaged cell membrane with many pores. Microanalysis showed a significant decrease in the cellular content of magnesium, phosphorus, sodium, potassium and chlorine, and an increase in calcium. Plakoglobin immunoreactivity in the cell membrane was decreased, indicating a decrease in the number of desmosomes.Conclusions: The results point to poly-L-arginine induced membrane damage, resulting in increased permeability, loss of cell-cell contacts and generalized cell damage.


Author(s):  
Hyung-Rho Kim ◽  
Hye-Won Rho ◽  
Byung-Hyun Park ◽  
Jin-Woo Park ◽  
Jong-Suk Kim ◽  
...  

Author(s):  
Kanchana Suksri ◽  
Namoiy Semprasert ◽  
Mutita Junking ◽  
Suchanoot Kutpruek ◽  
Thawornchai Limjindaporn ◽  
...  

Long-term medication with dexamethasone (a synthetic glucocorticoid (GC) drug) results in hyperglycemia, or steroid-induced diabetes. Although recent studies revealed dexamethasone directly induces pancreatic β-cell apoptosis, its molecular mechanisms remain unclear. In our initial analysis of mRNA transcripts, we discovered the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) pathway may be involved in dexamethasone-induced pancreatic β-cell apoptosis. In the present study, a mechanism of dexamethasone-induced pancreatic β-cell apoptosis through the TRAIL pathway was investigated in cultured cells and isolated mouse islets. INS-1 cells were cultured with and without dexamethasone in the presence or absence of a glucocorticoid receptor (GR) inhibitor, RU486. We found that dexamethasone induced pancreatic β-cell apoptosis in association with the upregulation of TRAIL mRNA and protein expression. Moreover, dexamethasone upregulated the TRAIL death receptor (DR5) protein but suppressed the decoy receptor (DcR1) protein. Similar findings were observed in mouse isolated islets: dexamethasone increased TRAIL and DR5 compared to that of control mice. Furthermore, dexamethasone stimulated pro-apoptotic signaling including superoxide production, caspase-8, -9, and -3 activities, NF-B, and Bax, but repressed the anti-apoptotic protein, Bcl-2. All these effects were inhibited by the GR-inhibitor, RU486. Furthermore, knock down DR5 decreased dexamethasone-induced caspase 3 activity. Caspase-8 and caspase-9 inhibitors protected pancreatic β-cells from dexamethasone-induced apoptosis. Taken together, dexamethasone induced pancreatic β-cell apoptosis by binding to the GR and inducing DR5 and TRAIL pathway.


2018 ◽  
Vol 137 ◽  
pp. 179-192 ◽  
Author(s):  
Sihle E. Mabhida ◽  
Phiwayinkosi V. Dludla ◽  
Rabia Johnson ◽  
Musawenkosi Ndlovu ◽  
Johan Louw ◽  
...  

2020 ◽  
Vol 153 ◽  
pp. 17-25
Author(s):  
Soyeon Yoo ◽  
Ju Young Bae ◽  
Jaecheol Moon ◽  
Gwanpyo Koh
Keyword(s):  

2008 ◽  
Vol 294 (3) ◽  
pp. E540-E550 ◽  
Author(s):  
Elida Lai ◽  
George Bikopoulos ◽  
Michael B. Wheeler ◽  
Maria Rozakis-Adcock ◽  
Allen Volchuk

Chronic exposure to elevated saturated free fatty acid (FFA) levels has been shown to induce endoplasmic reticulum (ER) stress that may contribute to promoting pancreatic β-cell apoptosis. Here, we compared the effects of FFAs on apoptosis and ER stress in human islets and two pancreatic β-cell lines, rat INS-1 and mouse MIN6 cells. Isolated human islets cultured in vitro underwent apoptosis, and markers of ER stress pathways were elevated by chronic palmitate exposure. Palmitate also induced apoptosis in MIN6 and INS-1 cells, although the former were more resistant to both apoptosis and ER stress. MIN6 cells were found to express significantly higher levels of ER chaperone proteins than INS-1 cells, which likely accounts for the ER stress resistance. We attempted to determine the relative contribution that ER stress plays in palmitate-induced β-cell apoptosis. Although overexpressing GRP78 in INS-1 cells partially reduced susceptibility to thapsigargin, this failed to reduce palmitate-induced ER stress or apoptosis. In INS-1 cells, palmitate induced apoptosis at concentrations that did not result in significant ER stress. Finally, MIN6 cells depleted of GRP78 were more susceptible to tunicamycin-induced apoptosis but not to palmitate-induced apoptosis compared with control cells. These results suggest that ER stress is likely not the main mechanism involved in palmitate-induced apoptosis in β-cell lines. Human islets and MIN6 cells were found to express high levels of stearoyl-CoA desaturase-1 compared with INS-1 cells, which may account for the decreased susceptibility of these cells to the cytotoxic effects of palmitate.


2016 ◽  
Vol 157 (19) ◽  
pp. 733-739 ◽  
Author(s):  
Miklós Csala

The increasing prevalence of type 2 diabetes correlates with the rapid spread of obesity worldwide. Adipocytes are strained by the demand of excessive storage, and the local inflammation accelerates triglyceride turnover, which elevates the plasma levels of free fatty acids. Sustained hyper-free fatty acidemia leads to disturbances in cellular functions (lipotoxicity) or even to programmed cell death. Activated stress kinases interfere with insulin signaling, and often facilitate apoptosis. Hyper-free fatty acidemia, therefore, links obesity to diabetes through insulin resistance and β-cell damage. Lipotoxicity research – including the comparison of the effects exerted by saturated, unsaturated and trans fatty acids – provides explanations for long-known phenomena. Our widening knowledge in the field offers new strategies for prevention and treatment of the metabolic syndrome and diabetes. Orv. Hetil., 2016, 157(19), 733–739.


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