Differential alterations of ethanolamine and choline phosphoglyceride metabolism by clofibrate and retinoic acid in human fibroblasts are not mediated by phorbol ester-sensitive protein kinase C

Lipids ◽  
1996 ◽  
Vol 31 (7) ◽  
pp. 747-755 ◽  
Author(s):  
Suzan G. Mandla ◽  
David M. Byers ◽  
Neale D. Ridgway ◽  
Harold W. Cook
Keyword(s):  
Protein Kinase C ◽  
Retinoic Acid ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Human Fibroblasts ◽  
Kinase C ◽  
Choline Phosphoglyceride

Effect of differentiation on platelet-activating factor metabolism in HL-60 cells

1991 ◽  
Vol 100 (1) ◽  
pp. 145-152
Author(s):  
L.L. Stoll ◽  
N.R. Yerram ◽  
A.A. Spector
Keyword(s):  
Protein Kinase C ◽  
Retinoic Acid ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Biological Effects ◽  
Platelet Activating Factor ◽  
Human Leukocyte ◽  
The Other ◽  
Kinase C ◽  
Acid Produce

The formation and metabolism of 1-O-alkyl-2-acetyl-sn-glycerol (AAG), a protein kinase C (PKC) activator formed from platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3- phosphocholine; PAF), was studied in HL-60 cells to determine whether differentiation may influence this process. HL-60 cells differentiated to macrophages (HL-60/M phi) with a phorbol ester convert added [3H]PAF to AAG; 22% of the incorporated radioactivity is converted to AAG within 15s. By contrast, neither undifferentiated HL-60 cells (HL-60/U) nor HL-60 cells differentiated to granulocytes (HL-60/GN) with retinoic acid produce AAG from PAF. The HL-60/M phi rapidly convert radiolabeled AAG to 1-O-alkyl-sn-glycerol and, subsequently, to two other unidentified metabolites. However, some apparently unmodified AAG persists in the cell lipids for at least 6 h. The HL-60 subtypes which do not convert PAF to AAG can nevertheless catabolize AAG; HL-60/U and HL-60/GN produce alkylglycerol and the other AAG metabolites. These findings demonstrate that differentiation can alter the processing of PAF in a human leukocyte cell line. Furthermore, they suggest that PAF may produce at least some of its biological effects in macrophages by conversion to AAG.

Effect of retinoic acid on contractile competence of vascular smooth muscle

1996 ◽  
Vol 270 (4) ◽  
pp. H1363-H1370 ◽  
Author(s):  
G. Wright ◽  
S. Wang ◽  
G. Bailey ◽  
V. Reichenbecher ◽  
G. L. Wright
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Retinoic Acid ◽  
Protein Kinase ◽  
Organ Culture ◽  
Phorbol Ester ◽  
Contractile Response ◽  
Contractile Function ◽  
Fresh Tissue ◽  
Kinase C

Rat aortic rings cultured for 24 h in protein-free medium showed a significant reduction in the contractile response to potassium (-60%) and to phorbol 12,13-dibutyrate (-65%). The addition of plasma to the medium attenuated the loss in responsiveness, and the supplementation of the plasma-containing medium with all trans-retinoic acid (RA) returned the response to potassium (85%) and phorbol ester (135%) to near normal or supramaximal compared with fresh tissue. Furthermore, the combined additions of plasma and RA resulted in significant preservation of the contractile response (75%) for at least 3 days in organ culture. Removal of the endothelium before organ culture eliminated the enhancement of contraction by plasma and RA. However, the removal of the endothelium from tissues that had been cultured with an intact endothelium or the blockade of nitric oxide synthesis in these tissues before contractile measurements had no effect on the contractile response. Finally, the incubation of tissues with phorbol ester to downregulate protein kinase C resulted in a marked attenuation (-75%) of the contractile response compared with control tissues in culture. The results suggest that circulating factors may be necessary for the maintenance of contractile function of aortic smooth muscle. Based on the opposing actions of RA and phorbol ester, the long-term regulation of contractile function may involve protein kinase C activity.

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