Cloning and sequencing of the proximal promoter of the rat iNOS gene: activation of NFκB is not sufficient for transcription of the iNOS gene in rat mesangial cells

Abstract

Key words: iNOS regulation; iNOS promoter; Endothelin-1 ; NF~cB activation; Oct-l; Mesangial cell; Rat kidney hibitory effects have been shown for TGF-I3, PDGF, IL-4, glucocorticoids, cyclosporin A, angiotensin II and endothelin-I (ET-I). These studies were performed mainly in macrophages [8][9][10] as well as vascular smooth muscle cells (VSMCs) or MCs [11][12][13][14][15][16][17]. Most of the inhibitory effects occur at the transcriptional level. On the other hand, posttranscriptional and posttranslational effects, e.g. for TGF-I3 , have also been described. The published data show that the regulation of iNOS expression is highly cell and species specific. This renders the elucidation of a universal signaling pathway for iNOS regulation more difficult. Cloning of murine [18], human [19,20] and rat iNOS promoters has enabled us to examine transcriptional effects with authentic promoter fragments.We have recently reported that ET-1 inhibits iNOS expression induced by TNF-c~ and IL-I[3 via the ETA receptor in rat MCs [17]. Our data indicated that the inhibition occurs at the transcriptional level. The present study was performed to further improve our understanding of the molecular mechanisms involved in the inducing or inhibitory effects on iNOS expression.

Inhibition of NFκB‐mediated pro‐inflammatory gene expression in rat mesangial cells by the enolized 1,3‐dioxane‐4,6‐dione‐5‐carboxamide, CGP‐43182

“…Nuclear factor kB (NFkB) is known to be involved in IL1b-induced group IIA sPLA 2 , Cox-2 and iNOS gene expression in mesangial cells (Walker et al, 1995;1997;Martin et al, 1994;Beck & Sterzel 1996;Eberhardt et al, 1994;1998) and thus seems to be a common denominator of cytokine-induced production of in¯ammatory mediators (Barnes & Karin 1997;Mercurio & Manning 1999;Pfeilschifter & MuÈ hl 1999).…”

Src Activation of NF-κB Augments IL-1β–Induced Nitric Oxide Production in Mesangial Cells

“…Mesangial cells contribute prominently to the pathogenesis of glomerulonephritis, in part by producing a variety of cytokines and NO via iNOS, and there is evidence for participation of iNOS-generated NO in the induction, progression, or protection of several types of experimental and human glomerulonephritis. Proinflammatory stimuli, such as IL-1␤ (4), activate iNOS gene transcription in mesangial cells through a complex network of signaling pathways and inducible transcription factors, including c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (5), cAMP response element binding protein (CREB) (4), CCAAT-enhancer binding protein (C/EBP␤) (4), and NF-B (6). Of these, NF-B is considered the most potent transactivator of the iNOS gene and has been the subject of more intense investigation.…”

Role of Interferon Regulatory Factor-1 in Double-stranded RNA-induced iNOS Expression by Mouse Islets

“…These transcription factors regulate cellular antiviral responses, including the expression of antiviral proteins (type I IFN, PKR, and major histocompatibility complex class I), control of cell cycle progression, and induction of apoptosis (29 -31). Binding elements for both IRF-1 and NF-B are found in the promoter regions of the rat, mouse, and human iNOS genes (32)(33)(34). In addition, IRF-1 and NF-B have been shown to physically interact at the iNOS promoter region, potentially leading to the synergistic activation of iNOS expression observed when both transcription factors are activated (35).…”