Inhibition of Prolyl Hydroxylase Domain-Containing Protein Suppressed Lipopolysaccharide-Induced TNF-α Expression

• Published in: Arteriosclerosis, thrombosis, and vascular biology Vol. 29; no. 12; pp. 2132 - 2137
• Main Authors: Takeda, Kotaro, Ichiki, Toshihiro, Narabayashi, Eriko, Inanaga, Keita, Miyazaki, Ryohei, Hashimoto, Toru, Matsuura, Hirohide, Ikeda, Jiro, Miyata, Toshio, Sunagawa, Kenji
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.12.2009; Lippincott Williams & Wilkins
• Subjects: Amino Acids, Dicarboxylic - pharmacology; Animals; Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Cell Line; Cytokines - biosynthesis; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Drug toxicity and drugs side effects treatment; Enzyme Inhibitors - pharmacology; Humans; Hypoxia-Inducible Factor 1, alpha Subunit - genetics; Hypoxia-Inducible Factor 1, alpha Subunit - metabolism; Hypoxia-Inducible Factor-Proline Dioxygenases; Lipopolysaccharides - toxicity; Macrophages - drug effects; Macrophages - metabolism; Macrophages, Peritoneal - drug effects; Macrophages, Peritoneal - metabolism; Medical sciences; Mice; NF-kappa B - genetics; NF-kappa B - metabolism; Pharmacology. Drug treatments; Procollagen-Proline Dioxygenase - antagonists & inhibitors; Procollagen-Proline Dioxygenase - genetics; RNA Interference; Toxicity: blood; Transcriptional Activation; Tumor Necrosis Factor-alpha - biosynthesis; Up-Regulation - drug effects; Oxygen; Cytokine; Cardiovascular disease; Inflammation; hypoxia-inducible factor; Vascular disease; prolyl hydroxylase domain-containing protein; Tumor necrosis factor; Atherosclerosis; Lipopolysaccharide; Hypoxia; tumor necrosis factor -alpha; Tumor necrosis factor α
• ISSN: 1079-5642; 1524-4636
• DOI: 10.1161/ATVBAHA.109.196071

OBJECTIVE—Prolyl hydroxylase domain-containing proteins (PHDs) play pivotal roles in oxygen-sensing system through the regulation of α-subunit of hypoxia-inducible factor (HIF), a key transcription factor governing a large set of gene expression to adapt hypoxia. Although tissue hypoxia plays an essential role in maintaining inflammation, the role of PHDs in the inflammatory responses has not been clearly determined. Here, we investigated the role of PHDs in lipopolysaccharide (LPS)-induced tumor necrosis factor α (TNF-α) induction in macrophages. METHODS AND RESULTS—Northern blot analysis and ELISA revealed that LPS-induced TNF-α upregulation was strongly suppressed by PHD inhibitors, dimethyloxallyl glycine (DMOG), and TM6008 in RAW264.7 macrophages. DMOG suppressed LPS-induced TNF-α upregulation in HIF-1α–depleted cells and HIF-1α overexpression failed to suppress the induction of TNF-α. DMOG rather suppressed LPS-induced NF-κB transcriptional activity. Downregulation of Phd1 or Phd2 mRNA by RNA interference partially attenuated LPS-induced TNF-α induction. DMOG also inhibited LPS-induced TNF-α production in peritoneal macrophages as well as human macrophages. CONCLUSIONS—PHD inhibition by DMOG or RNA interference inhibited LPS-induced TNF-α upregulation in macrophages possibly through NF-κB inhibition, which is independent of HIF-1α accumulation. This study suggests that PHDs are positive regulators of LPS-induced inflammatory process, and therefore inhibition of PHD may be a novel strategy for the treatment of inflammatory diseases.