scholarly journals Arachidonic Acid Induces Direct Interaction of the p67phox-Rac Complex with the Phagocyte Oxidase Nox2, Leading to Superoxide Production

2014 ◽  
Vol 289 (36) ◽  
pp. 24874-24884 ◽  
Author(s):  
Rumi Matono ◽  
Kei Miyano ◽  
Takuya Kiyohara ◽  
Hideki Sumimoto
Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4733
Author(s):  
Kiran Reddi ◽  
Hanxuan Li ◽  
Wei Li ◽  
Sarada Tetali

Berberine (BBR), a plant alkaloid, is known for its therapeutic properties of anticancer, cardioprotective, antidiabetic, hypolipidemic, neuroprotective, and hepatoprotective activities. The present study was to determine the molecular mechanism of BBR’s pharmacological activity in human monocytic (THP-1) cells induced by arachidonic acid (AA) or lipopolysaccharide (LPS). The effect of BBR on AA/LPS activated proinflammatory markers including TNF-α, MCP-1, IL-8 and COX-2 was measured by ELISA or quantitative real-time PCR. Furthermore, the effect of BBR on LPS-induced NF-κB translocation was determined by immunoblotting and confocal microscopy. AA/ LPS-induced TNF-α, MCP-1, IL-6, IL-8, and COX-2 markers were markedly attenuated by BBR treatment in THP-1 cells by inhibiting NF-κB translocation into the nucleus. Molecular modeling studies suggested the direct interaction of BBR to IKKα at its ligand binding site, which led to the inhibition of the LPS-induced NF-κB translocation to the nucleus. Thus, the present study demonstrated the anti-inflammatory potential of BBR via NF-κB in activated monocytes, whose interplay is key in health and in the pathophysiology of atherosclerotic development in blood vessel walls. The present study findings suggest that BBR has the potential for treating various chronic inflammatory disorders.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2386-2386
Author(s):  
Chaekyun Kim ◽  
Mary C. Dinauer

Abstract Rac2 is a hematopoietic-specific Rho-GTPase implicated as an important constituent of the NADPH oxidase complex. We previously showed that Rac2 plays a stimulus-specific role in regulating NADPH oxidase activation and other functional responses in neutrophils [Kim and Dinauer, JI 166, 2001]. Here we investigate the effect of arachidonic acid (AA) on Rac2-regulated NADPH oxidase activity. Superoxide production in rac2-/- neutrophils was significantly lower (~4-fold) than that of wild-type when stimulated with PMA or AA alone. However, exogenously added AA (10 μM) fully restored the defect in PMA-elicited NADPH oxidase activity in rac2−/ − neutrophils, while having no effect on FMLP-elicited superoxide production. Impaired PMA- or AA-induced F-actin polymerization in rac2−/ − neutrophils was also not restored by co-stimulation with PMA and AA. Taken together, these observations suggest that there are agonist- and pathway-specific differences in the underlying basis of functional defects in rac2−/ − neutrophils. To further investigate possible mechanisms of AA-mediated rescue of PMA-stimulated NADPH oxidase activation in rac2−/ − neutrophils, we measured protein expression and activity of cytosolic phospholipase A2 (cPLA2) and protein kinase C (PKC). The expression of cPLA2 and PMA-stimulated release of AA was similar between wild-type and rac2−/ − neutrophils, suggesting that defects in AA production by PMA-stimulated rac2−/ − neutrophils do not account for the effect of exogenous AA on oxidase activity. The neutrophil expression of PKC isoforms (α, β, δ, ζ) was also similar between genotypes. The cytosolic p47phox and p67phox components of NADPH oxidase were translocated to the plasma membrane upon stimulation with PMA in both genotypes, and no additional translocation in either wild-type or rac2−/ − neutrophils was detected upon co-stimulation with AA. The level of activated Rac1-GTP was similar between genotypes following stimulation, and was not increased by co-stimulation with PMA and AA. These studies indicate that the addition of exogenous AA reconstitutes PMA-elicited superoxide production in rac2−/ − neutrophils independent of the effects on translocation of p47phox and p67phox and activation of Rac1 GTPase. We hypothesize that the effect of AA is exerted through conformational changes of the assembled NADPH oxidase.


1989 ◽  
Vol 46 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Jerry R. Heidel ◽  
Stephen M. Taylor ◽  
William W. Laegreid ◽  
Ron M. Silflow ◽  
H. Denny Liggitt ◽  
...  

1987 ◽  
Vol 247 (3) ◽  
pp. 773-777 ◽  
Author(s):  
M Goppelt-Strübe ◽  
H J Pfannkuche ◽  
D Gemsa ◽  
K Resch

Prostanoids are synthesized by resident macrophages upon stimulation with diacylglycerols. Oleoylacetylglycerol and dioctanoylglycerol induced prostaglandin E and thromboxane synthesis in a time- and concentration-dependent manner. Both diacylglycerols inhibited the lysophosphatide acyltransferase, which is the key enzyme in the reacylation of arachidonic acid. By this mechanism the pool of free arachidonic acid available for prostanoid synthesis is increased. Both diacylglycerols were able to inhibit the membrane-bound lysophosphatide acyltransferase by a direct interaction independent of protein kinase C. Thus lysophosphatide acyltransferase could be shown to be a new target of these diacylglycerols, known as activators of protein kinase C.


2012 ◽  
Vol 1818 (9) ◽  
pp. 2314-2324 ◽  
Author(s):  
H. Souabni ◽  
V. Thoma ◽  
T. Bizouarn ◽  
C. Chatgilialoglu ◽  
A. Siafaka-Kapadai ◽  
...  

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