Phosphorylation of 5-lipoxygenase at Ser523 by protein kinase A determines whether pioglitazone and atorvastatin induce proinflammatory leukotriene B4 or anti-inflammatory 15-epi-lipoxin A4 production

The 5-lipoxygenase (5LO) produces leukotriene B 4 and 15-epilipoxin-A 4 (15-epi-LXA 4 ). Phosphorylation at Ser 523 by protein kinase A (PKA) prevents 5LO shift to the perinuclear membrane. Atorvastatin and pioglitazone up-regulate 15-epi-LXA 4 production in the heart. We assessed whether phosphorylation of 5LO by PKA determines whether 5LO interacts with the membranous cytosolic phospholipase A 2 (cPLA 2 ) to produce leukotriene B 4 or with cyclooxygenase-2 (COX2) to produce 15-epi-LXA 4 . Rats received either pioglitazone, atorvastatin, pioglitazone plus atorvastatin, vehicle, or LPS. Rat myocardial cells were incubated with pioglitazone plus atorvastatin, pioglitazone plus atorvastatin plus H-89 (PKA inhibitor), H-89, or vehicle for 8 h. Pioglitazone and atorvastatin did not affect total 5LO expression. However, both increased 5LO levels in the cytosolic fraction. H-89 caused a shift of 5LO to the membranous fraction in atorvastatin- and pioglitazone-treated rats. Pioglitazone and atorvastatin increased phospho-5LO levels. H-89 attenuated this increase. Both pioglitazone and atorvastatin increased COX2 levels in the cytosolic fraction and the membranous fraction. H-89 prevented this increase. Pioglitazone and atorvastatin increased cPLA 2 expression in the membranous fraction. This effect was not attenuated by H-89. Pioglitazone plus atorvastatin increased 15-epi-LXA 4 levels. H-89 attenuated the effect of pioglitazone plus atorvastatin. Pioglitazone plus atorvastatin plus H-89 increased leukotriene B 4 levels. Coimmunoprecipitation showed that without H-89, atorvastatin and pioglitazone induced an interaction between 5LO and COX2 in the cytosolic fraction, whereas when H-89 was added, 5LO interacted with cPLA 2 on the membranous fraction. The 5LO phosphorylation determines whether 15-epi-LXA 4 (anti-inflammatory) or leukotriene B 4 (inflammatory mediator) is produced.