Induction of apoptosis in rat lymphocytes by starvation

2006 ◽  
Vol 112 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Juliana Pires ◽  
Rui Curi ◽  
Rosemari Otton

The aim of the present study was to investigate whether fasting for 24 and 48 h induces apoptosis of rat mesenteric lymph node lymphocytes similar to that observed previously in diabetic patients and alloxan-induced diabetic rats. Several features of lymphocyte death were evaluated by flow cytometry. Plasma levels of glucose, NEFAs (non-esterified fatty acids) and ketone bodies (acetoacetate and β-hydroxybutyrate) were determined in rats fasted for 24 and 48 h. Lymphocytes obtained from fasted rats had an increase in DNA fragmentation and phosphatidylserine externalization after 48 h of culture, although there was no loss of membrane integrity in lymphocytes even after 48 h of culture. Cytochrome c release from the mitochondrial intermembrane space into the cytosol was increased significantly in lymphocytes from fasted rats cultured for 24 h, whereas the levels of bcl-2 and bax proteins were not affected. Activities of caspases 3, 6, 8 and 9 were increased significantly in lymphocytes from rats fasted for 24 h, whereas only an increase in caspase 3 and 9 activities were observed in rats fasted for 48 h. In conclusion, fasting for 24 and 48 h caused a significant increase in the proportion of lymphocytes undergoing apoptosis. The occurrence of apoptosis was observed by DNA fragmentation, phosphatidylserine externalization, cytochrome c release from the mitochondria and activation of the caspase cascade. These findings support the hypothesis that conditions that raise plasma fatty acids levels (e.g. diabetes and starvation) may impair immune function by causing lymphocyte death.

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 182 ◽  
Author(s):  
Massimo Malerba ◽  
Raffaella Cerana

Fusicoccin (FC) is a well-known phytotoxin able to induce in Acer pseudoplatanus L. (sycamore) cultured cells, a set of responses similar to those induced by stress conditions. In this work, the possible involvement of peroxynitrite (ONOO−) in FC-induced stress responses was studied measuring both in the presence and in the absence of 2,6,8-trihydroxypurine (urate), a specific ONOO− scavenger: (1) cell death; (2) specific DNA fragmentation; (3) lipid peroxidation; (4) production of RNS and ROS; (5) activity of caspase-3-like proteases; and (6) release of cytochrome c from mitochondria, variations in the levels of molecular chaperones Hsp90 in the mitochondria and Hsp70 BiP in the endoplasmic reticulum (ER), and of regulatory 14-3-3 proteins in the cytosol. The obtained results indicate a role for ONOO− in the FC-induced responses. In particular, ONOO− seems involved in a PCD form showing apoptotic features such as specific DNA fragmentation, caspase-3-like protease activity, and cytochrome c release from mitochondria.


2005 ◽  
Vol 289 (6) ◽  
pp. H2310-H2318 ◽  
Author(s):  
Takayuki Okada ◽  
Hajime Otani ◽  
Yue Wu ◽  
Shiori Kyoi ◽  
Chiharu Enoki ◽  
...  

Activation of p38 mitogen-activated protein (MAP) kinase (MAPK) has been implicated in the mechanism of cardiomyocyte (CMC) protection and injury. The p38 MAPK controversy may be related to differential effects of this kinase on apoptosis and necrosis. We have hypothesized that p38 MAPK-mediated F-actin reorganization promotes apoptotic cell death, whereas it protects from osmotic stress-induced necrotic cell death. Cultured neonatal rat CMCs were subjected to 2 h of simulated ischemia followed by reoxygenation. p38 MAPK activity measured by phosphorylation of MAP kinase-activated protein (MAPKAP) kinase 2 was increased during simulated ischemia and reoxygenation. This was associated with translocation of heat shock protein 27 (HSP27) from the cytosolic to the cytoskeletal fraction and F-actin reorganization. Cytochrome c release from mitochondria, caspase-3 activation, and DNA fragmentation were increased during reoxygenation. Robust lactate dehydrogenase (LDH) release was observed under hyposmotic (140 mosM) reoxygenation. The p38 MAPK inhibitor SB-203580 abrogated activation of p38 MAPK, translocation of HSP27, and F-actin reorganization and prevented cytochrome c release, caspase-3 activation, and DNA fragmentation. Conversely, SB-203580 enhanced LDH release during hyposmotic reoxygenation. The F-actin disrupting agent cytochalasin D inhibited F-actin reorganization and prevented cytochrome c release, caspase-3 activation, and DNA fragmentation, whereas it enhanced LDH release during hyposmotic reoxygenation. When CMCs were incubated under the isosmotic condition for the first 15 min of reoxygenation, SB-203580 and cytochalasin D increased ATP content of CMCs and prevented LDH release after the conversion to the hyposmotic condition. These results suggest that F-actin reorganization mediated by activation of p38 MAPK plays a differential role in apoptosis and protection against osmotic stress-induced necrosis during reoxygenation in neonatal rat CMCs; however, the sarcolemmal fragility caused by p38 MAPK inhibition can be reversed during temporary blockade of physical stress during reoxygenation.


Stroke ◽  
2001 ◽  
Vol 32 (8) ◽  
pp. 1906-1911 ◽  
Author(s):  
Shobu Namura ◽  
Izumi Nagata ◽  
Shinya Takami ◽  
Hiroyuki Masayasu ◽  
Haruhiko Kikuchi

Blood ◽  
2002 ◽  
Vol 99 (2) ◽  
pp. 655-663 ◽  
Author(s):  
Joya Chandra ◽  
Emma Mansson ◽  
Vladimir Gogvadze ◽  
Scott H. Kaufmann ◽  
Freidoun Albertioni ◽  
...  

Abstract The purine nucleoside 2-chlorodeoxyadenosine (CdA) is often used in leukemia therapy. Its efficacy, however, is compromised by the emergence of resistant cells. In the present study, 3 CdA-resistant cell lines were generated and characterized. Their ability to accumulate 2-chloroadenosine triphosphate (CdATP) varied, reflecting differences in activities of deoxycytidine kinase (dCK) and deoxyguanosine kinase (dGK). Nonetheless, the selected lines were uniformly resistant to CdA-induced apoptosis, as assessed by caspase activation and DNA fragmentation. In contrast, cytosols from resistant cells were capable of robust caspase activation when incubated in the presence of cytochrome c and dATP. Moreover, replacement of dATP with CdATP also resulted in caspase activation in the parental and some of the resistant cell lines. Strikingly, CdA-induced decreases in mitochondrial transmembrane potential and release of cytochrome c from mitochondria were observed in the parental cells but not in any resistant lines. The lack of cytochrome c release correlated with an increased ability of mitochondria from resistant cells to sequester free Ca2+. Consistent with this enhanced Ca2+buffering capacity, an early increase in cytosolic Ca2+after CdA treatment of parental cells but not resistant cells was detected. Furthermore, CdA-resistant cells were selectively cross-resistant to thapsigargin but not to staurosporine- or Fas-induced apoptosis. In addition, CdA-induced caspase-3 activation and DNA fragmentation were inhibited by the Ca2+ chelator BAPTA-AM in sensitive cells. Taken together, the data indicate that the mechanism of resistance to CdA may be dictated by changes in Ca2+-sensitive mitochondrial events.


2001 ◽  
Vol 21 (5) ◽  
pp. 568-576 ◽  
Author(s):  
Ping-An Li ◽  
Ingrid Rasquinha ◽  
Qing Ping He ◽  
Bo K. Siesjö ◽  
Katalin Csiszár ◽  
...  

Previous histopathologic results have suggested that one mechanism whereby hyperglycemia (HG) leads to exaggerated ischemic damage involves fragmentation of DNA. DNA fragmentation in normoglycemia (NG) and HG rats subjected to 30 minutes of forebrain ischemia was studied by terminal deoxynucleotidyl transferase mediated DNA nick-labeling (TUNEL) staining, by pulse-field gel electrophoresis (PFGE), and by ligation-mediated polymerase chain reaction (LM-PCR). High molecular weight DNA fragments were detected by PFGE, whereas low molecular weight DNA fragments were detected using LM-PCR techniques. The LM-PCR procedure was performed on DNA from test samples with blunt (without Klenow polymerase) and 3′-recessed ends (with Klenow polymerase). In addition, cytochrome c release and caspase-3 activation were studied by immunocytochemistry. Results show that HG causes cytochrome c release, activates caspase-3, and exacerbates DNA fragments induced by ischemia. Thus, in HG rats, but not in control or NGs, TUNEL-stained cells were found in the cingulate cortex, neocortex, thalamus, and dorsolateral crest of the striatum, where neuronal death was observed by conventional histopathology, and where both cytosolic cytochrome c and active caspase-3 were detected by confocal microscopy. In the neocortex, both blunt-ended and stagger-ended fragments were detected in HG, but not in NG rats. Electron microscopy (EM) analysis was performed in the cingulate cortex, where numerous TUNEL-positive neurons were observed. Although DNA fragmentation was detected by TUNEL staining and electrophoresis techniques, EM analysis failed to indicate apoptotic cell death. It is concluded that HG triggers a cell death pathway and exacerbates DNA fragmentation induced by ischemia.


2011 ◽  
Vol 300 (4) ◽  
pp. H1361-H1372 ◽  
Author(s):  
Susana Ravassa ◽  
Amaia Zudaire ◽  
Richard D. Carr ◽  
Javier Díez

Activation of apoptosis contributes to cardiomyocyte dysfunction and death in diabetic cardiomyopathy. The peptide glucagon-like peptide-1 (GLP-1), a hormone that is the basis of emerging therapy for type 2 diabetic patients, has cytoprotective actions in different cellular models. We investigated whether GLP-1 inhibits apoptosis in HL-1 cardiomyocytes stimulated with staurosporine, palmitate, and ceramide. Studies were performed in HL-1 cardiomyocytes. Apoptosis was induced by incubating HL-1 cells with staurosporine (175 nM), palmitate (135 μM), or ceramide (15 μM) for 24 h. In staurosporine-stimulated HL-1 cardiomyocytes, phosphatidylserine exposure, Bax-to-Bcl-2 ratio, Bad phosphorylation (Ser136), BNIP3 expression, mitochondrial membrane depolarization, cytochrome c release, caspase-3 activation, DNA fragmentation, and mammalian target of rapamycin (mTOR)/p70S6K phosphorylation (Ser2448 and Thr389, respectively) were assessed. Apoptotic hallmarks were also measured in the absence or presence of low (5 mM) and high (10 mM) concentrations of glucose. In addition, phosphatidylserine exposure and DNA fragmentation were analyzed in palmitate- and ceramide-stimulated cells. Staurosporine increased apoptosis in HL-1 cardiomyocytes. GLP-1 (100 nM) partially inhibited staurosporine-induced mitochondrial membrane depolarization and completely blocked the rest of the staurosporine-induced apoptotic changes. This cytoprotective effect was mainly mediated by phosphatidylinositol 3-kinase (PI3K) and partially dependent on ERK1/2. Increasing concentrations of glucose did not influence GLP-1-induced protection against staurosporine. Furthermore, GLP-1 inhibited palmitate- and ceramide-induced phosphatidylserine exposure and DNA fragmentation. Incretin GLP-1 protects HL-1 cardiomyocytes against activation of apoptosis. This cytoprotective ability is mediated mainly by the PI3K pathway and partially by the ERK1/2 pathway and seems to be glucose independent. It is proposed that therapies based on GLP-1 may contribute to prevent cardiomyocyte apoptosis.


Drug Research ◽  
2020 ◽  
Vol 70 (02/03) ◽  
pp. 112-118 ◽  
Author(s):  
Enaytollah Seydi ◽  
Tina Servati ◽  
Fatemeh Samiei ◽  
Parvaneh Naserzadeh ◽  
Jalal Pourahmad

AbstractPioglitazone (PG) is one of the thiazolidinedione (TZDs) drugs used in diabetic patients. TZDs are known as peroxisome proliferator-activated receptor gamma (PPARγ) agonists. Mitochondria are considered as one of the targets of these drugs. The mechanisms of the effect of PG on mitochondria are not well understood. In this study, we investigated the effect of PG on mitochondria isolated from brain and heart. Mitochondrial parameters such as succinate dehydrogenase (SDH) activity, reactive oxygen species (ROS) generation, collapse in mitochondrial membrane potential (MMP), mitochondrial swelling and cytochrome c release were evaluated. The results showed that PG at concentrations of 12.5, 25 and 50 µg/ml increased the generation of ROS, the collapse of MMP, mitochondrial swelling and the release of cytochrome c in mitochondria isolated from both brain and heart tissues. The underlying mechanisms of PG induced neuro-toxicity and cardio-toxicity may be associated with changes in mitochondrial function, ROS generation (oxidative stress), and changes in the mitochondrial membrane.


2001 ◽  
Vol 281 (4) ◽  
pp. G1115-G1123 ◽  
Author(s):  
Junpei Soeda ◽  
Shinichi Miyagawa ◽  
Kenji Sano ◽  
Junya Masumoto ◽  
Shun'Ichiro Taniguchi ◽  
...  

Apoptosis plays an important role in liver ischemia and reperfusion (I/R) injury. However, the molecular basis of apoptosis in I/R injury is poorly understood. The aims of this study were to ascertain when and how apoptotic signal transduction occurs in I/R injury. The apoptotic pathway in rats undergoing 90 min of warm ischemia with reperfusion was compared with that of rats undergoing prolonged ischemia alone. During ischemia, mitochondrial cytochrome c was released into the cytosol in a time-dependent manner in hepatocytes and sinusoidal endothelial cells, and caspase-3 and an inhibitor of caspase-activated DNase were cleaved. However, apoptotic manifestation and DNA fragmentation were not observed. After reperfusion, nuclear condensation, cells positive for terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling, and DNA fragmentation were observed and caspase-8 and Bid cleavage occurred. In contrast, prolonged ischemia alone induced necrosis rather than apoptosis. In summary, our results show that release of mitochondrial cytochrome c and caspase activation proceed during ischemia, although apoptosis is manifested after reperfusion.


2003 ◽  
Vol 285 (5) ◽  
pp. G980-G991 ◽  
Author(s):  
Sujoy Bhattacharya ◽  
Ramesh M. Ray ◽  
Mary Jane Viar ◽  
Leonard R. Johnson

Intracellular polyamine homeostasis is important for the regulation of cell proliferation and apoptosis and is necessary for the balanced growth of cells and tissues. Polyamines have been shown to play a role in the regulation of apoptosis in many cell types, including IEC-6 cells, but the mechanism is not clear. In this study, we analyzed the mechanism by which polyamines regulate the process of apoptosis in response to tumor necrosis factor-α (TNF-α). TNF-α or cycloheximide (CHX) alone did not induce apoptosis in IEC-6 cells. Significant apoptosis was observed when CHX was given along with TNF-α, as indicated by a significant increase in the detachment of cells, caspase-3 activity, and DNA fragmentation. Polyamine depletion by treatment with α-difluoromethylornithine significantly reduced the level of apoptosis, as judged by DNA fragmentation and the caspase-3 activity of attached cells. Apoptosis in IEC-6 cells was accompanied by the activation of upstream caspases-6, -8, and -9 and NH2-terminal c-Jun kinase (JNK). Inhibition of JNK activation prevented caspase-9 activation. Polyamine depletion prevented the activation of JNK and of caspases-6, -8, -9, and -3. SP-600125, a specific inhibitor of JNK activation, prevented cytochrome c release from mitochondria, JNK activation, DNA fragmentation, and caspase-9 activation in response to TNF-α/CHX. In conclusion, we have shown that polyamine depletion delays and decreases TNF-α-induced apoptosis in IEC-6 cells and that apoptosis is accompanied by the release of cytochrome c, the activation of JNK, and of upstream caspases as well as caspase-3. Polyamine depletion prevented JNK activation, which may confer protection against apoptosis by modulation of upstream caspase-9 activation.


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