title: HIV protease inhibitor lopinavir-induced TNF-alpha and IL-6 expression is coupled to the unfolded protein response and ERK signaling pathways in macrophages.
abstract: HIV protease inhibitor (PI)-associated cardiovascular risk, especially atherosclerosis, has become a major concern in the clinic. Macrophages are key players in the inflammatory response and atherosclerosis formation. We have previously shown that HIV PIs induce endoplasmic reticulum (ER) stress, activate the unfolded protein response (UPR), and increase the synthesis of the inflammatory cytokines, TNF-alpha and IL-6, by regulating the intracellular translocation of RNA binding protein HuR in macrophages. However, the underlying signaling mechanisms remain unclear. We show here that the HIV PI lopinavir significantly activated the extracellular-signal regulated protein kinase (ERK), but not c-Jun N-terminal kinase (JNK) and p38 MAPK. Lopinavir-induced cytosolic translocation of HuR and TNF-alpha and IL-6 synthesis was attenuated by specific chemical inhibitor of MEK (PD98058) or over-expression of dominant negative mutant of MEK1. In addition, we demonstrated that lopinavir-induced ERK activation and TNF-alpha and IL-6 expression were completely inhibited in macrophages from CHOP null mice. Taken together, these results indicate activation of the UPR plays an essential role in HIV PI-induced inflammatory cytokine synthesis and release by activating ERK, which increases the cytosolic translocation of HuR and subsequent binding to the 3'UTR of TNF-alpha and IL-6 mRNAs in macrophages.
authors.affiliation: Department of Microbiology & Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Sirikalaya
authors.initials: S
authors.lastname: Jarujaron
authors.forename: Xudong
authors.initials: X
authors.lastname: Wu
authors.forename: Lixin
authors.initials: L
authors.lastname: Sun
authors.forename: Weibin
authors.initials: W
authors.lastname: Zha
authors.forename: Guang
authors.initials: G
authors.lastname: Liang
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
authors.forename: Emily C
authors.initials: EC
authors.lastname: Gurley
authors.forename: Elaine J
authors.initials: EJ
authors.lastname: Studer
authors.forename: Phillip B
authors.initials: PB
authors.lastname: Hylemon
authors.forename: William M
authors.initials: WM
authors.lastname: Pandak
authors.forename: Luyong
authors.initials: L
authors.lastname: Zhang
authors.forename: Guangji
authors.initials: G
authors.lastname: Wang
authors.forename: Xiaokun
authors.initials: X
authors.lastname: Li
authors.forename: Paul
authors.initials: P
authors.lastname: Dent
authors.forename: Huiping
authors.initials: H
authors.lastname: Zhou
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D007948:Leukemia, Monocytic, Acute; D061466:Lopinavir; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D016328:NF-kappa B / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011489:Protein Denaturation; D011744:Pyrimidinones / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D017320:HIV Protease Inhibitors; D015850:Interleukin-6; D016328:NF-kappa B; D011744:Pyrimidinones; D014409:Tumor Necrosis Factor-alpha; D061466:Lopinavir; D019869:Phosphatidylinositol 3-Kinases; D048049:Extracellular Signal-Regulated MAP Kinases