Weikang Sun,Ke Ren,Jingjing Li,Mengyu Zhang,Qishen Jiang,Lingling Wang,Erguang Li
(199 words) The c-Jun N-terminal kinase (JNK) signaling pathway is required for herpes simplex virus 1 lytic infection and reactivation from latency. JNK signaling regulates cellular processes in response to stress through transcriptional regulation. However, the mechanisms by which JNK regulates HSV-1 infection are less defined. We show here that HSV-1 infection triggers BRD4 transition from chromosome association to transcriptional regulation for viral infection. Specifically, HSV-1 infection induces JNK activation which mediates redistribution of BRD4, an epigenetic reader protein, from chromatin-targeting to association with proteins of transcriptional regulation. BRD4 transitions to viral infection regulation by complexing with P-TEFb, a positive transcription elongation factor, and association with viral DNA. Genetic ablation or perturbation of JNK with chemical inhibitors or siRNA leads to impediment of BRD4 release and inhibition of HSV-1 infection. Both chemotherapeutic agents and irradiation are known to promote JNK activation and HSV reactivation. We show further that JNK agonist or chemotherapeutic agents known to activate JNK have the ability to enhance HSV-1 infection. Our study reveals a novel mechanism by which JNK regulates HSV-1 infection through stress-induced BRD4 function transition from host chromosome association to viral gene expression. The work links recurrent HSV infection by chemotherapeutic agents to JNK activation.
GFH009 is a potent, highly selective, small molecule that targets and inhibits the activity of the CDK9/cyclin T1 regulatory complex of P-TEFb. This study aimed to develop and validate a highly selective and sensitive ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method for precise quantification of GFH009 in rat plasma. This method was subsequently employed for conducting toxicokinetic studies of GFH009 in rats. Plasma was prepared using a simple protein precipitation method by acetonitrile. Chromatographic separation of the analytes was achieved on a BEH C 18 analytical column with a rapid 3.0 min run time and a flow rate of 0.5 ml/min. The calibration curves for plasma samples exhibited excellent linearity over a wide concentration range of 1.0–1,000 ng/ml for GFH009. Intra- and inter-day accuracies were within 92.7–105.7%, and precisions were no more than 6.7%. Furthermore, the analyte demonstrated stability under four different storage conditions, with variations of <15.0%. This study pioneers a methodological innovation by introducing a highly reliable, specific and sensitive analytical method for GFH009 in rat plasma. The successful application of this method in toxicokinetic studies further underscores its significance, offering valuable insights for the methodology of clinical pharmacokinetic research.
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