scholarly journals Nitric oxide-induced apoptosis: p53-dependent and p53-independent signalling pathways

1996 ◽  
Vol 319 (1) ◽  
pp. 299-305 ◽  
Author(s):  
Udo K MESSMER ◽  
Bernhard BRÜNE
Keyword(s):  
Dna Fragmentation ◽  
Antisense Rna ◽  
Apoptotic Cell ◽  
No Synthase ◽  
Signalling Pathways ◽  
Raw 264.7 ◽  
Raw 264.7 Macrophages ◽  
Inducible No Synthase ◽  
Induced Apoptosis ◽  
Tumour Suppressor P53

Nitric oxide (NO) generation initiates apoptotic cell death in different experimental systems. In RAW 264.7 macrophages the appearance of typical apoptotic markers is linked to inducible NO synthase induction. Mechanistically, accumulation of tumour suppressor p53 precedes apoptotic DNA fragmentation. With the use of S-nitroglutathione (GSNO) we correlated a dose-dependent p53 up-regulation to DNA fragmentation measured after 4 h and 8 h, respectively. Our studies revealed a linear correlation between the potency of five different NO donors with respect to apoptosis induction and p53 accumulation. Furthermore, we probed for NO-induced apoptosis after stable transfection of RAW 264.7 macrophages with plasmids encoding p53 antisense RNA. Clones with down-regulated p53 levels in response to GSNO exhibited a marked reduction in DNA fragmentation. Expression of the inducible NO synthase in response to lipopolysaccharide and interferon-γcaused apoptosis in RAW 264.7 macrophages and neomycin-vector controls within 24 h. In contrast, p53 antisense RNA-expressing clones appeared highly resistant towards endogenous NO, although inducible NO synthase induction with concomitant nitrite production remained unchanged. For RAW 264.7 macrophages our results established a functional role of the tumour suppressor p53 during NO-induced apoptotic cell death. However, p53 antisense experiments and the use of the p53-negative cell line U937 substantiated p53-independent signalling pathways operative during NO-mediated apoptosis.

scholarly journals Overexpression of CuZn superoxide dismutase protects RAW 264.7 macrophages against nitric oxide cytotoxicity

1999 ◽  
Vol 338 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Florian BROCKHAUS ◽  
Bernhard BRÜNE
Keyword(s):  
Nitric Oxide ◽  
Cell Death ◽  
Superoxide Dismutase ◽  
Uric Acid ◽  
No Synthase ◽  
Raw 264.7 ◽  
Down Regulation ◽  
Raw 264.7 Macrophages ◽  
Inducible No Synthase

Initiation of nitric oxide (NO•)-mediated apoptotic cell death in RAW 264.7 macrophages is associated with up-regulation of mitochondrial manganese superoxide dismutase (MnSOD; SOD2) and down-regulation of cytosolic copper zinc superoxide dismutase (CuZnSOD; SOD1) at their individual mRNA and protein levels. To evaluate the decreased CuZnSOD expression and the initiation of apoptosis we stably transfected macrophages to overexpress human CuZnSOD. Individual clones revealed a 2-fold increase in CuZnSOD activity. Expression of a functional and thus protective CuZnSOD was verified by attenuated superoxide (O2•-)-mediated apoptotic as well as necrotic cell death. In this study we showed that SOD-overexpressing macrophages (R-SOD1-12) were also protected against NO•-initiated programmed cell death. Protection was substantial towards NO• derived from exogenously added NO donors or when NO• was generated by inducible NO synthase activation, and was evident at the level of p53 accumulation, caspase activation and DNA fragmentation. Stimulation of parent and SOD-overexpressing cells with a combination of lipopolysaccharide and murine interferon γ produced equivalent amounts of nitrite/nitrate, which ruled out attenuated inducible NO• synthase activity during protection. Because protection by a O2•--scavenging system during NO•-intoxication implies a role of NO• and O2•- in the progression of cell damage, we used uric acid to delineate the role of peroxynitrite during NO•-elicited apoptosis. The peroxynitrite scavenger uric acid left S-nitrosoglutathione or spermine-NO-elicited apoptosis unaltered, blocking only 3-morpholinosydnonimine-mediated cell death. As a result we exclude peroxynitrite from contributing, to any major extent, to NO•-mediated apoptosis. Therefore protection observed with CuZnSOD overexpression is unlikely to stem from interference with peroxynitrite formation and/or action. Unequivocally, the down-regulation of CuZnSOD is associated with NO• cytotoxicity, whereas CuZnSOD overexpression protects macrophages from apoptosis.

scholarly journals NF-κB and AP-1 Activation by Nitric Oxide Attenuated Apoptotic Cell Death in RAW 264.7 Macrophages

1999 ◽  
Vol 10 (2) ◽  
pp. 361-372 ◽  
Author(s):  
Andreas von Knethen ◽  
Dagmar Callsen ◽  
Bernhard Brüne
Keyword(s):  
Nitric Oxide ◽  
Cell Death ◽  
Low Dose ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Raw 264.7 ◽  
Raw 264.7 Macrophages ◽  
Low Level ◽  
Ifn Γ ◽  
Cox 2

A toxic dose of the nitric oxide (NO) donorS-nitrosoglutathione (GSNO; 1 mM) promoted apoptotic cell death of RAW 264.7 macrophages, which was attenuated by cellular preactivation with a nontoxic dose of GSNO (200 μM) or with lipopolysaccharide, interferon-γ, and NG-monomethyl-l-arginine (LPS/IFN-γ/NMMA) for 15 h. Protection from apoptosis was achieved by expression of cyclooxygenase-2 (Cox-2). Here we investigated the underlying mechanisms leading to Cox-2 expression. LPS/IFN-γ/NMMA prestimulation activated nuclear factor (NF)-κB and promoted Cox-2 expression. Cox-2 induction by low-dose GSNO demanded activation of both NF-κB and activator protein-1 (AP-1). NF-κB supershift analysis implied an active p50/p65 heterodimer, and a luciferase reporter construct, containing four copies of the NF-κB site derived from the murine Cox-2 promoter, confirmed NF-κB activation after NO addition. An NF-κB decoy approach abrogated not only Cox-2 expression after low-dose NO or after LPS/IFN-γ/NMMA but also inducible protection. The importance of AP-1 for Cox-2 expression and cell protection by low-level NO was substantiated by using the extracellular signal-regulated kinase inhibitor PD98059, blocking NO-elicited Cox-2 expression, but leaving the cytokine signal unaltered. Transient transfection of a dominant-negative c-Jun mutant further attenuated Cox-2 expression by low-level NO. Whereas cytokine-mediated Cox-2 induction relies on NF-κB activation, a low-level NO–elicited Cox-2 response required activation of both NF-κB and AP-1.

INDUCTION OF INDUCIBLE NO-SYNTHASE IS AN ESSENTIAL PART OF TNFα-INDUCED APOPTOSIS IN MCF-7 CELLS

1996 ◽  
Vol 24 (4) ◽  
pp. 525S-525S
Author(s):  
C. Binder ◽  
M. Schulz ◽  
B. Fuß ◽  
W. Hiddemann ◽  
M. Oellerich
Keyword(s):  
No Synthase ◽  
Inducible No Synthase ◽  
Induced Apoptosis ◽  
Mcf 7

Redistribution of phosphatidylethanolamine and phosphatidylserine precedes reperfusion-induced apoptosis

1998 ◽  
Vol 274 (1) ◽  
pp. H242-H248 ◽  
Author(s):  
Nilanjana Maulik ◽  
Valerian E. Kagan ◽  
Vladimir A. Tyurin ◽  
Dipak K. Das
Keyword(s):  
Cell Death ◽  
Dna Fragmentation ◽  
Genomic Dna ◽  
High Performance ◽  
Apoptotic Cell ◽  
Ischemia Reperfusion ◽  
Apoptotic Cell Death ◽  
Dna Laddering ◽  
Outer Leaflet ◽  
Induced Apoptosis

Although cardiomyocyte death and infarction associated with ischemia-reperfusion are traditionally believed to be induced via necrosis, recent studies implicated apoptotic cell death in ischemic reperfused tissue. To examine whether myocardial ischemic reperfusion injury is mediated by apoptotic cell death, isolated perfused rat hearts were subjected to 15 and 30 min of ischemia as well as 15 min of ischemia followed by 30, 90, or 120 min of reperfusion. At the end of each experiment, hearts were processed for the evaluation of apoptosis and DNA laddering. Apoptosis was studied by visualizing the apoptotic cardiomyocytes by direct fluorescence detection of digoxigenin-labeled genomic DNA using APOPTAG in situ apoptosis detection kit. DNA laddering was evaluated by subjecting the DNA obtained from cardiomyocytes to 1.8% agarose gel electrophoresis and photographed under ultraviolet illumination. In addition, high-performance thin-layer chromatography (HPTLC) of aminophospholipids labeled with 2,4,6-trinitrobenzenesulfonate was performed to evaluate phospholipid topography in cardiomyocytes. The results of our study revealed apoptotic cells only in the 90- and 120-min reperfused hearts as demonstrated by the intense fluorescence of the immunostained digoxigenin-labeled genomic DNA when observed under fluorescence microscope. None of the ischemic hearts showed any evidence of apoptosis. These results corroborated with the findings of DNA fragmentation that showed increased ladders of DNA bands in the 120-min reperfused hearts, representing integer multiples of the internucleosomal DNA length (∼180 bp). Two-dimensional HPTLC of the phospholipids obtained from the cardiomyocytes and transbilayer organization of the phosphatidylethanolamine (PE) and phosphatidylserine (PS) in the myocytes indicated translocation of both PE and PS from the inner leaflet to the outer leaflet of the membrane as early as after 20 min of ischemia. These results demonstrate that the redistribution of PS and PE precedes the apototic cell death and DNA fragmentation associated with the reperfusion of ischemic myocardium, suggesting that ischemia may trigger the signal for apoptosis although it becomes evident during reperfusion.

scholarly journals Anti-inflammatory Effects of Empagliflozin and Gemigliptin on LPS-Stimulated Macrophage via the IKK/NF-κB, MKK7/JNK, and JAK2/STAT1 Signalling Pathways

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Nami Lee ◽  
Yu Jung Heo ◽  
Sung-E Choi ◽  
Ja Young Jeon ◽  
Seung Jin Han ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Inflammatory Responses ◽  
Sglt2 Inhibitor ◽  
Signalling Pathways ◽  
Raw 264.7 ◽  
Raw 264.7 Macrophages ◽  
Dipeptidyl Peptidase 4 ◽  
Qrt Pcr ◽  
M1 Macrophage ◽  
Anti Inflammatory

Background. Sodium-glucose cotransporter 2 (SGLT2) and dipeptidyl peptidase-4 (DPP-4) inhibitors are glucose-lowering drugs whose anti-inflammatory properties have recently become useful in tackling metabolic syndromes in chronic inflammatory diseases, including diabetes and obesity. We investigated whether empagliflozin (SGLT2 inhibitor) and gemigliptin (DPP-4 inhibitor) improve inflammatory responses in macrophages, identified signalling pathways responsible for these effects, and studied whether the effects can be augmented with dual empagliflozin and gemigliptin therapy. Methods. RAW 264.7 macrophages were first stimulated with lipopolysaccharide (LPS), then cotreated with empagliflozin, gemigliptin, or empagliflozin plus gemigliptin. We conducted quantitative RT-PCR (qRT-PCR) to determine the most effective anti-inflammatory doses without cytotoxicity. We performed ELISA and qRT-PCR for inflammatory cytokines and chemokines and flow cytometry for CD80, the M1 macrophage surface marker, to evaluate the anti-inflammatory effects of empagliflozin and gemigliptin. NF-κB, MAPK, and JAK2/STAT signalling pathways were examined via Western blotting to elucidate the molecular mechanisms of anti-inflammation. Results. LPS-stimulated CD80+ M1 macrophages were suppressed by coincubation with empagliflozin, gemigliptin, and empagliflozin plus gemigliptin, respectively. Empagliflozin and gemigliptin (individually and combined) inhibited prostaglandin E2 (PGE2) release and COX-2, iNOS gene expression in LPS-stimulated RAW 264.7 macrophages. These three treatments also attenuated the secretion and mRNA expression of proinflammatory cytokines, such as TNF-α, IL-1β, IL-6, and IFN-γ, and proinflammatory chemokines, such as CCL3, CCL4, CCL5, and CXCL10. All of them blocked NF-κB, JNK, and STAT1/3 phosphorylation through IKKα/β, MKK4/7, and JAK2 signalling. Conclusions. Our study demonstrated the anti-inflammatory effects of empagliflozin and gemigliptin via IKK/NF-κB, MKK7/JNK, and JAK2/STAT1 pathway downregulation in macrophages. In all cases, combined empagliflozin and gemigliptin treatment showed greater anti-inflammatory properties.

scholarly journals Fisetin, a dietary flavonoid induces apoptosis via modulating the MAPK and PI3K/Akt signalling pathways in human osteosarcoma (U-2 OS) cells

2015 ◽  
Vol 10 (4) ◽  
pp. 820 ◽  
Author(s):  
Jian-Ming Li ◽  
Wu-Yin Li ◽  
Man-Yu Huang ◽  
Xiao-Qiang Zhang
Keyword(s):  
High Frequency ◽  
Apoptotic Cell ◽  
Signalling Pathways ◽  
Ros Generation ◽  
Chemotherapeutic Drugs ◽  
Invasion And Metastasis ◽  
Human Osteosarcoma ◽  
Cell Counts ◽  
Dietary Flavonoid ◽  
Induced Apoptosis

<p>Human osteosarcoma is the most prevalent primary malignant bone tumor with high frequency of invasion and metastasis. Strong resistance coupled with toxicity of the currently available chemotherapeutic drugs poses challenge in treatment. The study aimed to investigate if fisetin, a dietary flavonoid induced apoptosis in human osteosarcoma (U-2 OS) cells. Fisetin at 20-100 µM effectively reduced the viability of OS cells, and induced apoptosis by significantly inducing the expression of caspases (Caspases- 3,-8 and -9) and pro-apoptotic proteins (Bax and Bad) with subsequent down-regulation of Bcl-xL and Bcl-2. While fisetin inhibited PI3K/Akt pathway and ERK1/2, it caused enhanced expressions of p-JNK, p-c-Jun and p-p38. Fisetin-induced ROS generation and decrease in mitochondrial membrane potential would have also contributed to rise in apoptotic cell counts. The observations suggest that fisetin was able to effectively induce apoptosis of U-2 OS cells through ROS generation and modulation of MAPK and PI3K/Akt signalling cascades.  </p><p> </p>

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