scholarly journals Mitochondrial reactive oxygen species promote production of proinflammatory cytokines and are elevated in TNFR1-associated periodic syndrome (TRAPS)

2011 ◽  
Vol 208 (3) ◽  
pp. 519-533 ◽  
Author(s):  
Ariel C. Bulua ◽  
Anna Simon ◽  
Ravikanth Maddipati ◽  
Martin Pelletier ◽  
Heiyoung Park ◽  
...  

Reactive oxygen species (ROS) have an established role in inflammation and host defense, as they kill intracellular bacteria and have been shown to activate the NLRP3 inflammasome. Here, we find that ROS generated by mitochondrial respiration are important for normal lipopolysaccharide (LPS)-driven production of several proinflammatory cytokines and for the enhanced responsiveness to LPS seen in cells from patients with tumor necrosis factor receptor-associated periodic syndrome (TRAPS), an autoinflammatory disorder caused by missense mutations in the type 1 TNF receptor (TNFR1). We find elevated baseline ROS in both mouse embryonic fibroblasts and human immune cells harboring TRAPS-associated TNFR1 mutations. A variety of antioxidants dampen LPS-induced MAPK phosphorylation and inflammatory cytokine production. However, gp91phox and p22phox reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits are dispensable for inflammatory cytokine production, indicating that NADPH oxidases are not the source of proinflammatory ROS. TNFR1 mutant cells exhibit altered mitochondrial function with enhanced oxidative capacity and mitochondrial ROS generation, and pharmacological blockade of mitochondrial ROS efficiently reduces inflammatory cytokine production after LPS stimulation in cells from TRAPS patients and healthy controls. These findings suggest that mitochondrial ROS may be a novel therapeutic target for TRAPS and other inflammatory diseases.

2011 ◽  
Vol 208 (3) ◽  
pp. 417-420 ◽  
Author(s):  
Edwina Naik ◽  
Vishva M. Dixit

High levels of reactive oxygen species (ROS) are observed in chronic human diseases such as neurodegeneration, Crohn’s disease, and cancer. In addition to the presence of oxidative stress, these diseases are also characterized by deregulated inflammatory responses, including but not limited to proinflammatory cytokine production. New work exploring the mechanisms linking ROS and inflammation find that ROS derived from mitochondria act as signal-transducing molecules that provoke the up-regulation of inflammatory cytokine subsets via distinct molecular pathways.


2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Asiya Parvin Allaudeen ◽  
Ajay Devendran ◽  
John E Baker ◽  
Anuradha Dhanasekaran

Erythropoietin (EPO) is a cytokine produced primarily in the kidney that is essential for red blood cell production. Apart from playing a role in hematopoiesis, EPO also has a protective role in heart myocytes, ovarian, glial cells brain and retinal diseases. In this study we observed that recombinant human EPO (rhEPO) reduces Hypoxia/ Reperfusion (H/R) injury by virtue of its effect on EPO receptor prosurvival signaling pathway, which ultimately leads to reduced expression of apoptotic proteins and increased survival of cardiomyocytes. H9C2 cells were exposed to H/R with or without pretreatment using 10, 15 and 20 U/ml of rhEPO. We determined viability using MTT, nuclear fragmentation by Hoechst staining, apoptotic nuclei by Acridine orange and Ethidium bromide, Reactive Oxygen Species (ROS) by Dicholorofluoresin Diacetate and activity of late apoptotic protease, Caspase-3 by colorimetric Caspase-3 assay. The expression of mitochondrial superoxide dismutase (MnSOD) by RT-PCR and Western blot, phospho-Akt and p38 MAPK by Confocal microscopy were analyzed. Cell viability is increased in cells pretreated with rhEPO compared to cell exposed to H/R. Cells subjected to H/R showed early apoptotic and late apoptotic cells but showed normal nuclei with intact cell membrane in cells pretreated with rhEPO. Intracellular production of ROS and Caspase-3 activity was decreased in cells pretreated with rhEPO compared to cells exposed to H/R. The expression of MnSOD RNA and protein was up-regulated in response to rhEPO, but not in H/R. The phosphorylative activation of Akt, p38MAPK progressively diminished during H/R but increased in rhEPO pretreated cells. We show that rhEPO prevents apoptosis in cardiomyocytes, subjected to H/R injury via phosphorylation of Akt and p38MAPK. These results it is hoped would help us distinguish the cell signaling pathways involved in cardioprotection and thus would open new avenues in cardiovascular therapy.


2009 ◽  
Vol 2 (5) ◽  
pp. 317-321 ◽  
Author(s):  
Camila Armond Isoni ◽  
Érica Abreu Borges ◽  
Clara Araújo Veloso ◽  
Rafael Teixeira Mattos ◽  
Miriam Martins Chaves ◽  
...  

Peripheral blood mononuclear cells (PBMNC) from patients with type 2 diabetes (DM2) have generated higher levels of reactive oxygen species (ROS) that were higher than those in cells from healthy individuals. In the presence of a cAMP-elevating agent, ROS production was significantly activated in PBMNC from DM2 patients but it was inhibited in cells from healthy subjects. Higher levels of IL-6 has been detected in the supernatant of PBMNC cultures from DM2 patients in comparison with healthy controls. When cells were cultured in the presence of a cAMP-elevating agent, the level of IL-6 decreased has by 46% in the supernatant of PBMNC from DM2 patients but it remained unaltered in controls. No correlations between ROS and IL-6 levels in PBMNC from DM2 patients or controls have been observed. Secretions of IL-4 or IFN by PBMNC from patients or controls have not been affected by the elevation of cAMP. cAMP elevating agents have activated the production of harmful reactive oxidant down modulated IL-6 secretion by these cells from DM2 patients, suggesting an alteration in the metabolic response possibly due to hyperglicemia. The results suggest that cAMP may play an important role in the pathogenesis of diabetes.


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