The Role of Phosphodiesterase 12 (PDE12) as a Negative Regulator of the Innate Immune Response and the Discovery of Antiviral Inhibitors.

The Journal of biological chemistry 2015 Aug 07

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2',5'-Oligoadenylate synthetase (OAS) enzymes and RNase-L constitute a major effector arm of interferon (IFN)-mediated antiviral defense. OAS produces a unique oligonucleotide second messenger, 2',5'-oligoadenylate (2-5A), that binds and activates RNase-L. This pathway is down-regulated by virus- and host-encoded enzymes that degrade 2-5A. Phosphodiesterase 12 (PDE12) was the first cellular 2-5A- degrading enzyme to be purified and described at a molecular level. Inhibition of PDE12 may up-regulate the OAS/RNase-L pathway in response to viral infection resulting in increased resistance to a variety of viral pathogens. We generated a PDE12-null cell line, HeLaΔPDE12, using transcription activator-like effector nuclease-mediated gene inactivation. This cell line has increased 2-5A levels in response to IFN and poly(I-C), a double-stranded RNA mimic compared with the parental cell line. Moreover, HeLaΔPDE12 cells were resistant to viral pathogens, including encephalomyocarditis virus, human rhinovirus, and respiratory syncytial virus. Based on these results, we used DNA-encoded chemical library screening to identify starting points for inhibitor lead optimization. Compounds derived from this effort raise 2-5A levels and exhibit antiviral activity comparable with the effects observed with PDE12 gene inactivation. The crystal structure of PDE12 complexed with an inhibitor was solved providing insights into the structure-activity relationships of inhibitor potency and selectivity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Citation

Edgar R Wood, Randy Bledsoe, Jing Chai, Philias Daka, Hongfeng Deng, Yun Ding, Sarah Harris-Gurley, Luz Helena Kryn, Eldridge Nartey, James Nichols, Robert T Nolte, Ninad Prabhu, Cecil Rise, Timothy Sheahan, J Brad Shotwell, Danielle Smith, Vince Tai, J David Taylor, Ginger Tomberlin, Liping Wang, Bruce Wisely, Shihyun You, Bing Xia, Hamilton Dickson. The Role of Phosphodiesterase 12 (PDE12) as a Negative Regulator of the Innate Immune Response and the Discovery of Antiviral Inhibitors. The Journal of biological chemistry. 2015 Aug 07;290(32):19681-96