| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Endocrinology Service and Research Unit, Puerta del Mar Hospital, Cadiz, Spain
(Requests for offprints should be addressed to M Aguilar-Diosdado, Servicio de Endocrinologia, Hospital Puerta del Mar, Avda Ana de Viya 21, 11009 Cádiz, Spain; Email: manuel.aguilar.sspa{at}juntadeandalucia.es)
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
and interferon (IFN)-
) displayed a significant increase in islet cell apoptosis when the islets were incubated in 24.4 mM glucose compared with untreated islets at the same glucose concentration (13.07 ± 1.78% vs 6.09 ± 0.78%; P < 0.01) or islets incubated in 5.5 mM glucose concentration and cytokines (13.07 ± 1.78% vs 8.04 ± 1.56%; P < 0.05). IL-1ß alone did not induce a significant increase in the apoptotic rates in islet cells cultured at normal or high glucose concentrations. STZ significantly increased islet cell apoptosis when islets were cultured in 24.4 mM glucose concentration compared with untreated islets at the same glucose concentration (6.02 ± 0.62% vs 4.44 ± 0.63%; P < 0.05). High glucose induced an increase in Fas expression in the islet cells, and this increase was maintained after cytokine or STZ treatment. However, the expression of anti-apoptotic mediators such as bcl-2 and bcl-xL did not show any significant change. These results suggest that cytokine- and STZ-mediated apoptotic effects on islet cells might be mediated by a glucose-induced hyperfunctional status and associated with an increase in Fas (Apo-1, CD-95) expression and no changes in the expression of the anti-apoptotic proteins bcl-xL and bcl-2. |
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
High glucose concentration impairs islet function by disturbing glucose metabolism in the mitochondria of ß-cells and could induce apoptosis (Sandler et al. 1990, Laybutt et al. 2001, Maedler et al. 2001). In addition, it has been reported that high glucose could increase ß-cell vulnerability to toxic damage by increasing the expression of potential autoantigens on the cell membrane surface (Aguilar-Diosdado et al. 1994).
Fas has also been postulated to play a role in the autoimmune ß-cell damage. The cell death receptor, Fas (CD95), seems to be implicated in ß-cell apoptosis via an intracellular death domain (Krammer 2000). Cytokines can induce up-regulation of Fas expression in ß-cells, making them susceptible to apoptosis in the presence of agonistic anti-Fas antibodies, or interaction with Fas-ligand (FasL, CD95 L)-expressing T-cells (Stassi et al. 1995, Yamada et al. 1996, Loweth et al. 1998). The role of Fas in ß-cell apoptosis is still the subject of debate, and has been challenged by several studies (Allison & Strasser 1998, Thomas et al. 1999). In addition, up-regulation of several anti-apoptotic members of the bcl-2 family of proteins, such as bcl-2 and bcl-xL, has been strongly associated with increased resistance to apoptosis and potentially linked with diabetes susceptibility (Garchon et al. 1994, Lamhamedi-Cherradi et al. 1998, Hanke 2000).
The aim of the current study was to determine whether high glucose concentration modifies the apoptosis mediated by STZ, IL-1ß or a combination of proinflamatory cytokines such as tumor necrosis factor (TNF)- ß, interferon (IFN)- and IL-1ß in rat pancreatic islet cells. In addition, we explored the expression level of potentially related apoptotic and anti-apoptotic molecules in rat islet cells treated with these various cell death inducers and different glucose concentrations. Our results suggest that high glucose concentration (a) potentiates cytokine- and STZ-mediated rat islet cell apoptosis and (b) increases the expression of Fas in these cells.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
All animal procedures were performed with the approval of the Animal Ethical Use and Care Committee at the Cadiz University School of Medicine, Cadiz, Spain. Pancreatic islets were isolated from adult male Wistar rats, as described previously (McDaniel et al. 1983). Isolated islets were cultured in RPMI medium (Sigma) supplemented with 2 mM L-glutamine (Gibco), 10% fetal bovine serum (Gibco), 100 U/ml penicillin and 100 µg/ml streptomycin (Pen-Strep; Bio-Whittaker Europe, Verviers, Belgium), and containing either 5.5 or 24.4 mmol/l glucose (Ling et al. 1994). A dose–response experiment was performed using 2, 5.5, 11.1, 24.4 and 33.3 mM glucose for measurement of different apoptosis rates.
Cytokines and STZ treatment
To determine whether glucose has any influence on cytokine-mediated apoptosis in rat islet cells, isolated islets cultured for 16–20 h with RPMI containing 5.5 or 24.4 mM glucose were then exposed for 24 h to either recombinant human IL-1ß (PeproTech EC Ltd, London, UK) alone or combined with recombinant human IFN- (PeproTech EC Ltd), and recombinant human TNF- (PeproTech EC Ltd). Cytokine concentrations used in these experiments (50 U/ml IL-1ß, 1000 U/ml IFN-, 1000 U/ml TNF-) were selected from previous studies (Eizirik et al. 1994, Delaney et al. 1997, Hoorens & Pipeleers 1999).
To analyze the effect of different glucose concentrations on STZ-induced apoptosis in rat islet cells, a different set of islets was cultured for 48 h with RPMI containing either 5.5 or 24.4 mM glucose. After that period of time, islets were exposed to STZ (1.5 mM; Sigma) for an additional 24 h period.
Detection of apoptotic cells
Apoptotic cells were detected using the TUNEL (Tdt-mediated dUTP nick-end labeling) technique. Following cytokines or STZ treatment, islets were incubated for 15 min with trypsin-EDTA: 0.25% trypsin, 1 mM EDTA·4Na in Hanks’ balanced salt solution without Ca2+ and Mg2+ (Gibco) at 37 °C, and islet cells were gently dispersed. After washing with PBS, cells were cytospun on poly-12-lysine-coated slides, fixed in 4% methanol-free formaldehyde solution in PBS for 25 min at 4 °C, and stored in 70% ethanol at –20 °C until detection of apoptotic cells by TUNEL assay. The TUNEL assay was performed according to the manufacturer’s instructions (Apoptosis Detection System, Fluorescein; Promega) (Efanova et al. 1998). The fluorescein-12-dUTP-labeled DNA was directly visualized by fluorescence microscopy with excitation at 520 ± 20 nm, to allow counting of the percentage of apoptotic cells (nuclei with green fluorescence). Cell nuclei were stained with propidium iodide (red fluorescence). Apoptotic and total nuclei were counted, in a blinded fashion, of more than 1000 cells with two slides per condition and per experiment.
Western blot
Equivalent numbers of islets treated with the various experimental conditions mentioned above were lysed in 60 mM Tris–HCl pH- 6–8, 2% SDS, 10% glycerol, 0.0012% bromophenol blue and 5% ß-mercaptoethanol. Islet lysates were boiled for 5 min and then loaded on a 10–12% SDS-polyacrylamide gel. Proteins were transferred to polyvinylidene fluoride (PDVF) membrane and the blot was then incubated in blocking buffer (5% non-fat milk in 10 mM Tris–HCl, 1.15 M NaCl and 0.1% Tween-20) for 1 h at room temperature. Next, blots were incubated with polyclonal antibodies against Fas (1:500 dilution; Santa Cruz Biotechnology Inc, Santa Cruz, CA, USA), bcl-xL (1:500 dilution; Santa Cruz Biotechnology), bcl-2 (1:100 dilution; Abcam Ltd, Cambridge, UK) or actin (1/5000 dilution; Abcam Ltd) for 2 h at room temperature, followed by incubation with the appropriate alkaline phosphatase-linked secondary antibody at room temperature for 1 h. Protein band detection was performed by adding 5-bromo-4-chloro-3-indolyl phosphate/nitro-blue tetrazolium (BCIP/NBT; Bio-Rad) to the membranes. Densitometry of the bands was quantitated using BioCaptMW-1 software.
Statistical analysis
Results are presented as means ± S.E.M. in at least three independent and separate experiments. Statistical analysis was performed using the Mann–Whitney test and a P value less than 0.05 was considered statistically significant.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
It has been recently reported that chronic exposure to high glucose leads to increased rat islet cell apoptosis (Piro et al. 2002). In that study, the apoptotic effect required at least 3 days of culture in high glucose concentration. In the current study we first analyzed rat islet cell apoptosis after incubation with 5.5 and 24.4 mM glucose for 2 days. As shown in Fig. 1A and B
, similar numbers of apoptotic cells per field were found in rat islet preparations incubated with either 5.5 or 24.4 mM glucose and, following quantitation, no significant differences in the apoptotic rates in these cells were found (Figs 2, 3 and 4). Based on these results, we decided to examine whether incubation with high glucose (24.4 mM) concentrations for 2 days might increase the sensitivity of islet cells to the apoptotic effects induced by cytokines or STZ. To ensure we had chosen the correct glucose concentration as control for the apoptotic rate of rat islet cells, a dose–response curve was produced. We observed an enhanced percentage of islet cell apoptosis with low (2 mM) and very high (33.3 mM) glucose concentrations in the medium, but not with 5.5, 11.1 or 24.4 mM glucose (Fig. 2).
|
|
|
|
Examination of TUNEL-stained cell preparations of islets maintained in 5.5 or 24.4 mM glucose for 48 h, and incubated with IL-1ß +TNF- +IFN- for the last 24 h, suggested that the number of apoptotic cells was increased when the islets were incubated in high glucose concentrations compared with normal glucose levels (Fig. 1C and D
). To confirm whether the apoptotic rates were increased, we performed a blinded systematic quantitation of the apoptotic rates in islet cells treated with the aforementioned conditions. As shown in Fig. 3, a dose of cytokines that was not able to induce a significant increase in islet cell apoptosis at 5.5 mM glucose was capable of inducing a significant two-fold increase in the apoptotic rates of islet cells maintained in 24.4 mM glucose. Apoptotic rates in islet cells incubated in high glucose increased from 6.09 ± 0.78 to 13.07 ± 1.78% (P < 0.01) when cytokines were added. This result indicates that although incubation with high glucose (24.4 mM) for 2 days does not increase rat islet cell death rates it makes cells more susceptible to the apoptotic effects induced by cytokines. The apoptotic cell rates in islets incubated in high glucose (24.4 mM) and treated with cytokines were significantly higher than the rates in islets treated with cytokines but incubated in 5.5 mM glucose (13.07 ± 1.78 vs 8.04 ± 1.56%, P < 0.05, Fig. 3). Interestingly, this effect was only observed when the three cytokines were used in combination since IL-1ß alone did not induce a significant increase in apoptosis at any glucose concentration tested.
Effect of high glucose on STZ-induced islet cell apoptosis
We next analyzed whether high glucose also increases the sensitivity of rat islet cells to apoptosis induced by STZ. As shown in Fig. 4 we chose a dose of STZ that did not significantly increase apoptotic rates in rat islet cells incubated in 5.5 mM glucose for 48 h. Interestingly, apoptosis was significantly increased (50%) when rat islets were incubated in 24.4 mM glucose for 48 h and with a low dose of STZ for an additional 24 h period (Fig. 4).
Collectively, the results described so far indicate that although incubation for 48 h with high glucose does not induce an increase in rat islet cell apoptosis, it potentiates the pro-apoptotic effects of cytokines and STZ in these cells.
Effect of high glucose on the expression levels of Fas, bcl-2 and bcl-x after cytokine or STZ treatment
Fas is a death receptor involved in apoptosis induced in various cell types including islet cells (Krammer 2000, Yamada et al. 1996, Stassi et al. 1995, Loweth et al. 1998). To determine whether glucose has any impact on the expression levels of Fas in rat islet cells treated with cytokines or STZ, we performed Western blot analysis of islet extracts incubated with the cell-death inducers in normal or high glucose. First, incubation of islet cells in high glucose for 2 days induced a significant increase (P < 0.05) in the expression of Fas (Figs 5 and 6). Interestingly, cytokines treatment of islets incubated in either 5.5 or 24.4 mM glucose did not induce a significant increase in the expression levels of Fas in these cells compared with control islets (Fig. 5). Similarly, STZ treatment did not significantly change Fas expression in rat islets incubated with 5.5 or 24.4 mM glucose compared with control islets incubated in the same glucose concentration (Fig. 6).
|
|
The expression levels of bcl-xL and bcl-2 anti-apoptotic proteins were also studied in rat islet cells incubated in different glucose concentrations and treated with the cytotoxic agents. As shown in Figs 5 and 6, we did not find any significant difference in the expression levels of both bcl-xL and bcl-2 in rat islets cultured at high or normal glucose, and treated with STZ or cytokines (Figs 5 and 6). However, while bcl-xL was clearly detected, bcl-2 was scarcely visible in all the conditions studied (Figs 5 and 6).
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
, IFN-) or STZ is modulated by glucose concentration. In the study described herein, we demonstrate that the presence of high glucose concentration enhances proinflammatory cytokine- and STZ-mediated apoptosis of rat pancreatic islet cells in vitro. In these experiments, we incubated rat islets in a high glucose concentration for a period of time (48 h) that does not result in islet cell apoptosis, as previously reported (Piro et al. 2002). In addition, we chose an incubation period (24 h) and concentrations of STZ and cytokines that did not induce islet cell apoptosis when incubated in normal glucose, as previously reported (Eizirik et al. 1997, Hoorens & Pipeleers 1999, Liu et al. 2002, Thomas et al. 2002). Importantly, under these conditions of high glucose, the apoptotic effects of cytokines and STZ in rat islet cells were strikingly potentiated. However, high glucose potentiation of the apoptotic effects of cytokines was greater than the potentiation of the apoptotic effects of STZ in these conditions. Both STZ (Turk et al. 1993) and cytokines (Kaneto et al. 1995, Dunger et al. 1996) have been shown to induce apoptosis in ß-cells and it is known that glucose concentration modifies mouse islet loss after STZ treatment (Eizirik et al. 1988), but the mechanisms involved are not well understood (Suarez-Pinzon et al. 1994). Our results suggest that mechanisms involved in cytokine-induced apoptosis could be more amplified by high glucose-induced hyperfunctional status of islet cells than the mechanisms implicated in STZ-mediated apoptotic effects. This effect also could be partially explained by the recently reported glucose-induced IL-1ß production by ß-cells (Maedler et al. 2002). Some differences between our study and others could be due to species, time course, glucose concentration in the culture media and experimental models used. Thus, although murine dispersed islet cells survive best at 11 mM glucose and apoptosis enhances when glucose is increased or decreased (Efanova et al. 1998), we show a similar U-shape curve but with no differences between 5.5, 11 and 24.4 mM in whole rat islets.
The molecular mechanisms of islet cell apoptosis are unclear. Increased expression of Fas has been related to ß-cell damage. The mechanisms underlying glucose-induced ß-cell death in human islets involve the up-regulation of Fas receptors, which can interact with the constitutively expressed FasL in neighboring ß-cells (Loweth et al. 1998). Fas–FasL interaction leads to cleavage of procaspase-8 to caspase-8 and activated caspase-8 promotes caspase-3 activation and DNA fragmentation (Stennicke & Salvesen 2000, Maedler et al. 2001). Human islets constitutively express FasL (Loweth et al. 1998) whereas islets from 2- to 3-month-old rats – the age of the rats chosen for our experiments – do not express FasL (Hanke 2000). Similar to the studies with human islets, we found that incubation with high glucose concentration for 2 days induces an increase in the expression of Fas in rat islet cells. This increase was sustained but not amplified when islets were treated with STZ or cytokines. Collectively, these results suggest that increased expression of Fas receptor in rat islets is not a predictor of enhanced islet cell apoptosis and other mechanisms might be implicated in the pro-apoptotic effect of STZ and cytokines in rat islet cells incubated in high glucose concentrations. Based on this, we analyzed whether the expression levels of two potential anti-apoptotic intracellular mediators – such as bcl-2 and bcl-xL that have been associated with increasing resistance to apoptosis (Garchon et al. 1994, Lamhamedi-Cherradi et al. 1998, Hanke 2000) – were down-regulated after treatment with STZ or cytokines in high glucose. The results indicate that bcl-2 was scarcely expressed and bcl-xL, although detected, did not show any significant variation in the expression level under any of the conditions studied. These findings suggest that bcl-2 and bcl-xL do not play an important role in STZ- and cytokine-induced apoptosis in rat islet cells incubated in high glucose concentrations. Further studies will be required to clarify the molecular mechanisms responsible for the high-glucose enhancement of islet cell apoptosis induced by cytokines and STZ.
In conclusion, our studies demonstrate that: (a) STZ-and cytokine-induced apoptosis of rat islet cells is potentiated by high glucose concentration in the culture medium; and (b) high glucose is associated with increased Fas expression in rat islet cells. As diabetes mellitus is caused by the loss of ß-cell mass, mainly caused by apoptosis, preventive interventions should be focused on achieving strict glucose control to avoid hyperfunctional status of pancreatic islet ß-cells.
|
Acknowledgements |
|---|
|
Funding |
|---|
This work was supported by grants from the Ministry of Health of Spain (FIS 99/1321), Andalusia Regional Government (SAS 177/99) and Instituto de Salud Carlos III, RGMD (G03/212). There has not been any conflict of interest that would have prejudiced the impartiality of the research.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Allison J & Strasser A 1998 Mechanisms of beta cell death in diabetes: a minor role for CD95. PNAS 95 13818–13822.
Augstein P, Elefanty AG, Allison J & Harrison LC 1998 Apoptosis and beta-cell destruction in pancreatic islets of NOD mice with spontaneous and cyclophosphamide-accelerated diabetes. Diabetologia 41 1381–1388.[CrossRef][Web of Science][Medline]
Castaño L & Eisenbarth GS 1990 Type 1 diabetes: a chronic autoimmune disease of human, mouse, and rat. Annual Review Immunology 8 647–679.
Delaney CA, Pavlovic D, Hoorens A, Pipeleers DG & Eizirik DL 1997 Cytokines induce deoxyribonucleic acid strand breaks and apoptosis in human pancreatic islet cells. Endocrinology 138 2610–2614.
Dunger A, Schroder D, Augstein P, Witstruck T, Wachlin G, Vogt L, Ziegler B & Schmidt S 1995 Impact of metabolic activity of beta cells on cytokine-induced damage and recovery of rat pancreatic islets. Acta Diabetologica 32 217–224.[CrossRef][Web of Science][Medline]
Dunger A, Augstein P, Schmidt S & Fisher U 1996 Identification of interleukin 1-induced apoptosis in rat islets using in situ specific labelling of fragmented DNA. Journal of Autoimmunity 9 309–313.[CrossRef][Web of Science][Medline]
Efanova IB, Zaitsev SV, Zhivotovsky B, Kohler M, Efendic S, Orrenius S & Berggren PO 1998 Glucose and tolbutamide induce apoptosis in pancreatic beta-cells: a process dependent on intracellular Ca2+ concentration. Journal of Biological Chemistry 273 33501–33507.
Eizirik DL, Strandell E, Sandler S 1988 Culture of mouse pancreatic islets in different glucose concentrations modifies B cell sensitivity to streptozotocin. Diabetologia 31 168–174.[CrossRef][Web of Science][Medline]
Eizirik DL, Sandler S, Welsh N, Cetkovic-Cvrlje M, Nieman A, Geller DA, Pipeleers DG, Bendtzen K & Hellerström C 1994 Cytokines suppress human islet function irrespective of their effects on nitric oxide generation. Journal of Clinical Investigation 93 1968–1974.
Garchon HJ, Luan JJ, Eloy L, Bédossa P & Bach JF 1994 Genetic analysis of immune dysfunction in non-obese diabetic (NOD) mice: mapping of a susceptibility locus close to the Bcl-2 gene correlates with increased resistance of NOD T cells to apoptosis induction. European Journal of Immunology 24 380–384.[Web of Science][Medline]
Gotfredsen CF, Buschard K & Frandsen EK 1985 Reduction of diabetes incidence of BB Wistar rats by early prophylactic insulin treatment of diabetes-prone animals. Diabetologia 28 933–935.[CrossRef][Web of Science][Medline]
Hanke J 2000 Apoptosis and occurrence of Bcl-2, Bak, Bax, Fas and FasL in the developing and adult rat endocrine pancreas. Anatomy and Embryology (Berlin) 202 303–312.
Hoorens A & Pipeleers D 1999 Nicotinamide protects human beta cells against chemically-induced necrosis, but not against cytokine-induced apoptosis. Diabetologia 42 55–59.[CrossRef][Web of Science][Medline]
Kaneto H, J Fujii H & Seo HG 1995 Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells. Diabetes 44 733–738.[Abstract]
Keller RJ, Eisenbarth GS & Jackson RA 1993 Insulin prophylaxis in individuals at high risk of type I diabetes. Lancet 341 927–928.[CrossRef][Web of Science][Medline]
Krammer PH 2000 CD95’s deadly mission in the immune system (Review). Nature 407 789–795.[CrossRef][Medline]
Kurrer MO, Pakala SV, Hanson HL & Katz JD 1997 Beta cell apoptosis in T cell-mediated autoimmune diabetes. PNAS 94 213–218.
Lamhamedi-Cherradi SE, Luan JJ, Eloy L, Fluteau G, Bach JF & Garchon HJ 1998 Resistance of T-cells to apoptosis in autoimmune diabetic (NOD) mice is increased early in life and is associated with dysregulation of Bcl-x. Diabetologia 41 178–184.[CrossRef][Web of Science][Medline]
Laybutt R, Hasenkamp W, Groff A, Grey S, Jonas JC, Kaneto H, Sharma A, Bonner-Weir S & Weir G 2001 Beta-cell adaptation to hyperglycemia. Diabetes 50 S180–S181.
Ling Z, Hannaert JC & Pipeleers D 1994 Effect of nutrients, hormones and serum on survival of rat islet beta cells in culture. Diabetologia 37 15–21.[Web of Science][Medline]
Liu D, Cardozo AK, Darville MI & Eizirik DL 2002 Double-stranded RNA cooperates with interferon- and IL-1ß to induce both chemokine expression and nuclear factor-
B-dependent apoptosis in pancreatic ß-cells: potential mechanisms for viral-induced insulitis and ß-cell death in type 1 diabetes mellitus. Endocrinology 143 1225–1234.
Loweth AC, Williams GT, James RF, Scarpello JH & Morgan NG 1998 Human islets of Langerhans express Fas ligand and undergo apoptosis in response to interleukin-1 beta and Fas ligation. Diabetes 47 727–732.[Abstract]
McDaniel ML, Colca JR, Kotagal N & Lacy PE 1983 A subcellular fractionation approach for studying insulin release mechanisms and calcium metabolism in islets of Langerhans. Methods Enzymology 98 182–200.[Web of Science][Medline]
Maedler K, Spinas GA, Lehmann R, Sergeev P, Weber M, Fontana A, Kaiser N & Donath MY 2001 Glucose induces beta-cell apoptosis via upregulation of the Fas receptor in human islets. 50 1683–1690.
Maedler K, Sergeev P, Ris F, Oberholzer J, Joller-Jemelka HI, Spinas GA, Kaiser N, Halban PA & Donath MY 2002 Glucose-induced beta cell production of IL-1 beta contributes to glucotoxicity in human pancreatic islets. Journal of Clinical Investigation 110 851–860.[CrossRef][Web of Science][Medline]
Mandrup-Poulsen T 1996 The role of interleukin-1 in the pathogenesis of IDDM. Diabetologia 39 1005–1029.[Medline]
Masutani M, Suzuki H, Kamada N, Watanabe M, Ueda O, Nozaki T, Jishage K, Watanabe T, Sugimoto T, Nakagama H, Ochiya T & Sugimura T 1999 Poly(ADP-ribose) polymerase gene disruption conferred mice resistant to streptozotocin-induced diabetes. PNAS 96 2301–2304.
O’Brien BA, Harmon BV, Cameron DP & Allan DJ 1997 Apoptosis is the mode of [beta]-cell death responsible for the development of IDDM in the nonobese diabetic (NOD) mouse. Diabetes 46 750–757.[Abstract]
Pavlovic D, Andersen NA, Mandrup-Poulsen T & Eizirik DL 2000 Activation of extracellular signal-regulated kinase (ERK)1/2 contributes to cytokine-induced apoptosis in purified rat pancreatic b-cells. European Cytokine Network 11 267–274.[Web of Science][Medline]
Piro S, Anello M, Di Pietro C, Lizzio MN, Patane G, Rabuazzo AM, Vigneri R, Purrello M & Purrelo F 2002 Chronic exposure to free fatty acids or high glucose induces apoptosis in rat pancreatic islets: possible role of oxidative stress. Metabolism 51 1340–1347.[CrossRef][Web of Science][Medline]
Sandler S, Bendtzen K, Eizirik DL, Strandell E, Welsh M & Welsh N 1990 Metabolism and beta-cell function of rat pancreatic islets exposed to human interleukin-1 beta in the presence of high glucose concentration. Immunology Letters 26 245–252.[CrossRef][Web of Science][Medline]
Shah SC, Malone JI & Simpson NE 1989 A randomized trial of intensive insulin therapy in newly diagnosed insulin-dependent diabetes mellitus. New England Journal of Medicine 320 550–554.[Abstract]
Stassi G, Todaro M, Richiusa P, Giordano M, Mattina A, Sbriglia MS, Lo MA, Buscemi G, Galluzzo A & Giordano C 1995 Expression of apoptosis-inducing CD95 (Fas/Apo-1) on human beta-cells sorted by flow-cytometry and cultured in vitro. Transplantation Proccedings 27 3271–3275.
Stennicke HR & Salvesen GS 2000 Caspases-controlling intracellular signals by protease zymogen activation. Biochimica et Biophysica Acta 1477 299–306.[CrossRef][Medline]
Suarez-Pinzon WL, Strinadka K, Schulz R & Rabinovitch 1994 A mechanism of cytokine-induced destruction of rat insulinoma cells: the role of nitric oxide, Endocrinology 134 1006–1010.
Thomas HE, Darwiche R, Corbett JA & Kay TW 1999 Evidence that beta cell death in the nonobese diabetic mouse is Fas independent. Journal of Immunology 163 1562–1569.
Thomas HE, Darwiche R, Corbett JA & Kay TW 2002 Interleukin-1 plus -interferon-induced pancreatic ß-cell dysfunction is mediated by ß-cell nitric oxide production. Diabetes 51 311–316.
Turk J, Corbett JA, Romanadham S, Bohrer A & McDaniel ML 1993 Biochemical evidence for nitric oxide formation from streptozotocin in isolated pancreatic islets. Biochemical and Biophysical Research Communications 197 1458–1464.[CrossRef][Web of Science][Medline]
Yamada K, Takane-Gyotoku N, Yuan X, Ichikawa F, Inada C & Nonaka K 1996 Mouse islet cell lysis mediated by interleukin-1-induced Fas. Diabetologia 39 1306–1312.[CrossRef][Web of Science][Medline]
Received 21 May 2004
Accepted 11 June 2004
This article has been cited by other articles:
|
|
 |
|
  T. Dai, M. Patel-Chamberlin, R. Natarajan, I. Todorov, J. Ma, J. LaPage, L. Phillips, C. C. Nast, D. Becerra, P. Chuang, et al. Heat Shock Protein 27 Overexpression Mitigates Cytokine-Induced Islet Apoptosis and Streptozotocin-Induced Diabetes Endocrinology, July 1, 2009; 150(7): 3031 - 3039. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M Blandino-Rosano, G Perez-Arana, J M Mellado-Gil, C Segundo, and M Aguilar-Diosdado Anti-proliferative effect of pro-inflammatory cytokines in cultured {beta} cells is associated with extracellular signal-regulated kinase 1/2 pathway inhibition: protective role of glucagon-like peptide -1 J. Mol. Endocrinol., July 1, 2008; 41(1): 35 - 44. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Robertson, Y. Lu, K. De Jesus, B. Li, Q. Su, P. K. Lund, and J.-L. Liu A general and islet cell-enriched overexpression of IGF-I results in normal islet cell growth, hypoglycemia, and significant resistance to experimental diabetes Am J Physiol Endocrinol Metab, May 1, 2008; 294(5): E928 - E938. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Riboulet-Chavey, F. Diraison, L. K. Siew, F. S. Wong, and G. A. Rutter Inhibition of AMP-Activated Protein Kinase Protects Pancreatic {beta}-Cells From Cytokine-Mediated Apoptosis and CD8+ T-Cell-Induced Cytotoxicity Diabetes, February 1, 2008; 57(2): 415 - 423. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Maedler, D. M. Schumann, N. Sauter, H. Ellingsgaard, D. Bosco, R. Baertschiger, Y. Iwakura, J. Oberholzer, C. B. Wollheim, B. R. Gauthier, et al. Low Concentration of Interleukin-1{beta} Induces FLICE-Inhibitory Protein-Mediated {beta}-Cell Proliferation in Human Pancreatic Islets. Diabetes, October 1, 2006; 55(10): 2713 - 2722. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Collier, P. T. Fueger, H. E. Hohmeier, and C. B. Newgard Pro- and Antiapoptotic Proteins Regulate Apoptosis but Do Not Protect Against Cytokine-Mediated Cytotoxicity in Rat Islets and {beta}-Cell Lines. Diabetes, May 1, 2006; 55(5): 1398 - 1406. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Y. Donath, J. A. Ehses, K. Maedler, D. M. Schumann, H. Ellingsgaard, E. Eppler, and M. Reinecke Mechanisms of {beta}-Cell Death in Type 2 Diabetes Diabetes, December 1, 2005; 54(suppl_2): S108 - S113. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Storling, S. V. Zaitsev, I. L. Kapelioukh, A. E. Karlsen, N. Billestrup, P.-O. Berggren, and T. Mandrup-Poulsen Calcium Has a Permissive Role in Interleukin-1{beta}-Induced c-Jun N-Terminal Kinase Activation in Insulin-Secreting Cells Endocrinology, July 1, 2005; 146(7): 3026 - 3036. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
