Differential Activation of NF-κB, AP-1, and C/EBP in Endotoxin-Tolerant Rats: Mechanisms for In Vivo Regulation of Glomerular RANTES/CCL5 Expression

Abstract

Chemokines play a pivotal role in the regulation of inflammatory cell infiltration in glomerular immune injury. To characterize mechanisms relevant for the regulation of chemokine expression in vivo, the LPS-mediated model of renal inflammation in rats was used in which we have previously demonstrated that the chemokine RANTES/CCL5 is expressed and secreted in glomeruli. Glomerular RANTES/CCL5 expression in this model correlated with an increased glomerular binding activity of the transcription factors AP-1, C/EBP, and NF-κB. To gain further insight into the functional roles of these transcription factors in the regulation of glomerular RANTES/CCL5 expression, we cloned the rat RANTES/CCL5 promoter and established the model of in vivo LPS tolerance. In tolerant rats, LPS-induced glomerular RANTES/CCL5 expression and activation of the transcription factors AP-1 and C/EBP were significantly reduced using both consensus and rat RANTES/CCL5-specific oligonucleotides. Reduced glomerular NF-κB binding activity after LPS injection could be demonstrated in tolerant rats only when using rat RANTES/CCL5-specific oligonucleotides. Reduced binding activity to this RANTES/CCL5-specific NF-κB binding site in the context of broad NF-κB activation might be due to changes in transcription factor interactions or chromatin remodeling processes.

Control of Transplant Tolerance and Intragraft Regulatory T Cell Localization by Myeloid-Derived Suppressor Cells and CCL5

“…CCL5 is a chemokine expressed commonly in inflammatory environments. It has a described immunomodulatory role in cancer, is also expressed and secreted in kidney glomeruli (46), and has been associated with renal transplant rejection or, alternatively, with long-term function (47,48). In this study, CCL5 mRNA was found to be upregulated long-term posttransplantation (our experiments were performed 3-4 mo posttransplantation) in tolerant kidney allografts compared with syngeneic kidney grafts (Fig.…”

Opposite Action of Peroxisome Proliferator-activated Receptor-γ in Regulating Renal Inflammation

“…As shown in Fig. 8A, there were two putative NF-B binding sites in the proximal promoter region of rat RANTES gene (31). Stimulation of mesangial cells with TNF-␣ increased p65 binding to B elements in rat RANTES promoter, as demonstrated in Fig.…”

“…The anti-p65 NF-B antibody (sc-109; Santa Cruz Biotechnology) was added and incubated at 4°C overnight, followed by incubation with protein A-agarose for 1 h. The precipitates were washed, and chromatin complexes were eluted. After reversal of the cross-linking at 65°C for 4 h, the DNA was purified, and ChIP samples were used as a template for PCR using the primer sets for rat RANTES promoter regions (from Ϫ114 to ϩ36) containing two putative B binding sites (31). The sequences of primers used for ChIP assay were as follows: forward, 5Ј-ctgacagcagccagggtttg-3Ј; and reverse, 5Ј-agatgcatgcgttgtctcag-3Ј, which generated a PCR product of 150 bp.…”

ATF4 is directly recruited by TLR4 signaling and positively regulates TLR4-trigged cytokine production in human monocytes

“…36,54 The study by An et al 26 has indicated that there is an AP-1 response element within the IL-6 promoter. The RANTES/CCL5 promoter displays binding activity with AP-1, C/EBP and NF-kB, 55 while the IL-8 promoter contains NF-kB, AP-1, OCT-1 and C/EBP-binding sites. [56][57][58] The studies by Hadad et al 59 and Clarke et al 60 have revealed that there is a CREB-binding site within the sICAM-1 and IFN-c promoter.…”