title: NF-κB Upregulates Type 5 Phosphodiesterase in N9 Microglial Cells: Inhibition by Sildenafil and Yonkenafil.
abstract: Our previous studies showed that the phosphodiesterase-5 (PDE5) inhibitor sildenafil inhibited the microglial activation induced by lipopolysaccharide (LPS). However, whether yonkenafil, a novel PDE5 inhibitor, also inhibits microglial activation and the underlying mechanism of inhibition remain elusive. Here we found that yonkenafil significantly suppressed the production of NO, interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) and the protein expression of inducible NO synthase (iNOS) induced by LPS in microglial cells in a concentration-dependent manner. Knockdown of PDE5 inhibits NO and iNOS protein expression in LPS-stimulated N9 microglia. Moreover, we observed that the nuclear factor-κB (NF-κB) transcriptionally upregulated PDE5 expression, which was inhibited by sildenafil and yonkenafil in LPS-stimulated N9 microglia. Therefore, sildenafil and yonkenafil may exert their inhibitory effects on microglial activation by reducing the expression of PDE5. Furthermore, sildenafil and yonkenafil increased the cyclic guanosine monophosphate (cGMP) level in N9 microglia, and 8-Br-cGMP, an analogue of cGMP, downregulates extracellular signal-regulated kinases 1 and 2 (ERK1/2)/the NF-κB pathway, suggesting that sildenafil and yonkenafil inhibit microglial activation by decreasing PDE5 expression and increasing the cGMP level. Importantly, sildenafil and yonkenafil significantly alleviated the death of SH-SY5Y neuroblastoma cells and primary cortical neurons induced by the conditioned medium from activated microglia. Together, these findings position PDE5 as a potential therapy target for the treatment of neuroinflammation accompanied by microglial activation.
authors.affiliation: Department of Pharmacology, Shenyang Pharmaceutical University, Box 31, 103 Wenhua Road, Shenyang, 110016, China.|State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Siqi
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Department of Pharmacology, Shenyang Pharmaceutical University, Box 31, 103 Wenhua Road, Shenyang, 110016, China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Pharmacology, Shenyang Pharmaceutical University, Box 31, 103 Wenhua Road, Shenyang, 110016, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Shengyi
authors.initials: S
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yin
authors.affiliation: Department of Pharmacology, Shenyang Pharmaceutical University, Box 31, 103 Wenhua Road, Shenyang, 110016, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Jia
authors.affiliation: Department of Pharmacology, Shenyang Pharmaceutical University, Box 31, 103 Wenhua Road, Shenyang, 110016, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. zqyuan@ibp.ac.cn.
authors.forename: Zengqiang
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Department of Pharmacology, Shenyang Pharmaceutical University, Box 31, 103 Wenhua Road, Shenyang, 110016, China. wucf@syphu.edu.cn.
authors.forename: Chunfu
authors.initials: C
authors.lastname: Wu
mesh_terms: D000818:Animals; D002460:Cell Line; D006152:Cyclic GMP / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000235:genetics / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D008070:Lipopolysaccharides; D051379:Mice; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009498:Neurotoxins / Q000633:toxicity; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011744:Pyrimidinones / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*; D034622:RNA Interference / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000068677:Sildenafil Citrate / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D016328:NF-kappa B; D009498:Neurotoxins; D010726:Phosphodiesterase Inhibitors; D011744:Pyrimidinones; D011758:Pyrroles; D012333:RNA, Messenger; C000613072:yonkenafil; D000068677:Sildenafil Citrate; D048049:Extracellular Signal-Regulated MAP Kinases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D006152:Cyclic GMP
keywords: LPS; Microglial activation; NF-κB; PDE5; cGMP