Direct and cytokine-mediated activation of protein kinase C induces human immunodeficiency virus expression in chronically infected promonocytic cells.
The chronically infected promonocytic clone U1 expresses low-to-undetectable constitutive levels of human immunodeficiency virus (HIV). Virus replication in these cells can be increased up to 25-fold by phorbol esters (phorbol-12-myristate-13-acetate), recombinant cytokines such as tumor necrosis factor-alpha, and cytokine-enriched mononuclear cell supernatants. We have tested specific activators of protein kinases (PK) and PK inhibitors (isoquinolinesulfonamide derivatives), as well as calcium-mobilizing agents, for their effect on constitutive and induced virus expression in U1 cells. Virus expression was measured by reverse transcriptase, Western blot, and nuclear run-on analysis. Activation of PKC by 1-oleyl,2-acetylglycerol, a synthetic analog of the natural ligand 1,2-diacylglycerol, and bryostatin 1 (a recently described specific PKC activator) resulted in a two- to eightfold increase in virus production. In contrast, activators of cyclic-nucleotide-dependent PKs were not effective in inducing virus expression. PK inhibitors were tested for their effect on HIV upregulation by cytokines and other inducing agents. The isoquinolinesulfonamide derivative H7, a potent inhibitor of PKC activation, effectively blocked (70 to 90%) HIV induction by cytokines and phorbol-12-myristate-13-acetate. The derivative HA1004, which is more selective for cyclic-nucleotide-dependent kinases, did not suppress viral induction. In addition, increases in intracellular calcium levels dramatically enhanced HIV production induced by both specific PKC activators and cytokines. These results indicate that activation of PKC is a common pathway involved in the upregulation of HIV expression in chronically infected cells stimulated by cytokines and other inducing agents.
Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
A L
AL
Kinter
G
G
Poli
W
W
Maury
T M
TM
Folks
A S
AS
Fauci
D001685:Biological Factors / Q000494:pharmacology*; D054713:Bryostatins; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation; D006160:Guanosine Triphosphate / Q000378:metabolism; D006678:HIV / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D006801:Humans; D007783:Lactones / Q000494:pharmacology; D015473:Leukemia, Promyelocytic, Acute; D018942:Macrolides; D008934:Mitogens / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014764:Viral Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D014779:Virus Replication
D001685:Biological Factors; D054713:Bryostatins; D016207:Cytokines; D004075:Diglycerides; D007783:Lactones; D018942:Macrolides; D008934:Mitogens; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D014764:Viral Proteins; C046785:bryostatin 1; D006160:Guanosine Triphosphate; C038237:1-oleoyl-2-acetylglycerol; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate