The expression of genes involved in the inflammatory response is controlled both transcriptionally and post-transcriptionally. Primary inflammatory stimuli, such as microbial products and the cytokines interleukin-1 (IL-1) and tumour necrosis factor alpha (TNF alpha), act through receptors of either the Toll and IL-1 receptor (TIR) family or the TNF receptor family. These cause changes in gene expression by activating four major intracellular signalling pathways that are cascades of protein kinases: namely the three mitogen-activated protein kinase (MAPK) pathways, and the pathway leading to activation of the transcription factor nuclear factor kappa B (NF kappa B). The pathways directly activate and induce the expression of a limited set of transcription factors which promote the transcription of inflammatory response genes. Many of the mRNAs are unstable, and are stabilized by the p38 MAPK pathway. Instability is mediated by clusters of the AUUUA motif in the 3' untranslated regions of the mRNAs. Control of mRNA stability provides a means of increasing the amplitude of a response and allows rapid adjustment of mRNA levels. Not all mRNAs stabilized by p38 contain AUUUA clusters; for example, matrix metalloproteinase-1 and -3 mRNAs lack these clusters, but are stabilized. Inflammatory gene expression is inhibited by glucocorticoids. These suppress MAPK signalling by inducing a MAPK phosphatase. This may be a significant mechanism additional to that by which the glucocorticoid receptor interferes with transcription factors.
"In human cells, DAF expression is modulated by cytokines such as IL-1, IL-6, TNF-α, TGF-β1, and IFN-γ [13–15], prostaglandin PGE2 , and tissue specific factors . Although there is evidence that DAF mRNA stability can be affected by tissue specific factors  and inflammation , most studies suggest that expression is primarily modulated at transcription [15–17, 19, 20]. The human DAF promoter has been identified, the transcription start site mapped, and regions of potential transcriptional regulation proposed [10, 21]. "
[Show abstract][Hide abstract] ABSTRACT: Decay accelerating factor (DAF), a complement-regulatory protein, protects cells from bystander complement-mediated lysis and negatively regulates T cells. Reduced expression of DAF occurs in several systemic autoimmune diseases including systemic lupus erythematosus, and DAF deficiency exacerbates disease in several autoimmune models, including murine mercury-induced autoimmunity (mHgIA). Daf1, located within Hmr1, a chromosome 1 locus associated in DBA/2 mice with resistance to mHgIA, could be a candidate. Here we show that reduced Daf1 transcription in lupus-prone mice was not associated with a reduction in the Daf1 transcription factor SP1. Studies of NZB mice congenic for the mHgIA-resistant DBA/2 Hmr1 locus suggested that Daf1 expression was controlled by the host genome and not the Hmr1 locus. A unique pentanucleotide repeat variant in the second intron of Daf1 in DBA/2 mice was identified and shown in F2 intercrosses to be associated with less severe disease; however, analysis of Hmr1 congenics indicated that this most likely reflected the presence of autoimmunity-predisposing genetic variants within the Hmr1 locus or that Daf1 expression is mediated by the tandem repeat in epistasis with other genetic variants present in autoimmune-prone mice. These studies argue that the effect of DAF on autoimmunity is complex and may require multiple genetic elements.
"DUSP1, also known as MKP1, is a member of the dualspecificity phosphatase family involved in the regulation of the innate immune function . Following p53-mediated transcription, DUSP1 targets p38, MAPKs, and JNKs which are important players in the expression of inflammatory mediators  . In addition, it mediates the cellular response to oxidative stress leading to apoptosis . "
[Show abstract][Hide abstract] ABSTRACT: The DUSP1 gene encodes a member of the dual-specificity phosphatase family previously identified as being differentially expressed in visceral adipose tissue (VAT) of severely obese men with versus without the metabolic syndrome. Objective. To test the association between DUSP1 polymorphisms, obesity-related metabolic complications, gene methylation, and expression levels in VAT. Methods. The DUSP1 locus and promoter region were sequenced in 25 individuals. SNPs were tested for association with obesity-related complications in a cohort of more than 1900 severely obese individuals. The impact of SNPs on methylation levels of 36 CpG sites and correlations between DNA methylation and gene expression levels in VAT were computed in a subset of 14 samples. Results. Heterozygotes for rs881150 had lower HDL-cholesterol levels (HDL-C; P = 0.01), and homozygotes for the minor allele of rs13184134 and rs7702178 had increased fasting glucose levels (P = 0.04 and 0.01, resp.). rs881150 was associated with methylation levels of CpG sites located ~1250 bp upstream the transcription start site. Methylation levels of 4 CpG sites were inversely correlated with DUSP1 gene expression. Conclusion. These results suggest that DUSP1 polymorphisms modulate plasma glucose and HDL-C levels in obese patients possibly through alterations of DNA methylation and gene expression levels.
International Journal of Genomics 08/2013; 2013(19):609748. DOI:10.1155/2013/609748 · 0.95 Impact Factor
"CB1 and CB2 receptors were shown to be involved in the regulation of the mitogen-activated protein kinases (MAPKs), including the extracellular signal-regulating kinase 1 and 2 (ERK1/2), p38 MAPK and c-Jun N-terminal kinase (JNK). Activated p38MAPK increases the recruitment of immune cells, activates lymphocytes and neutrophils and delays the apoptosis of these cells , , which are the major source of perpetual production of the inflammatory mediators. The present study shows an elevated expression of p38 and its phosphorylated form (pp38) in the intestinal tissues at 24 h POI, and this phenomenon is more pronounced in CB1–/– animals. "
[Show abstract][Hide abstract] ABSTRACT: Intestinal inflammatory responses play a critical role in the pathogenesis of postoperative ileus (POI). As cannabinoid receptor-1 (CB1) is involved in inhibiting gastrointestinal (GI) motility and anti-inflammation, we aimed to explore its contribution to POI.
Experimental POI was induced in adult female CB1-deficient (CB1-/-) mice and wild-type littermates (C57BL/6N) by standardized small bowel manipulation. Twenty-four hours after surgery, GI transit was assessed by charcoal transport. FITC avidin, F4/80, and myeloperoxidase immunohistochemistry techniques were used to evaluate the inflammatory response in the muscularis of ileum and colon. Expressions of p38MAPK and its phosphorylated form (pp38) in the intestine were determined. Plasma levels of proinflammatory cytokines and chemokines were measured by ELISA as well.
POI was characterized by decreased GI transit (p<0.01) and accompanied by a marked intestinal and systematic inflammatory response in wild-type and CB1-/- mice. Increased numbers of inflammatory cells, including macrophages, neutrophils, and mast cells were observed in the muscularis of ileum and colon (p<0.01, or p<0.05). Plasma levels of interleukin-6 (IL-6), cytokine-induced neutrophil chemoattractant-1 (CINC-1/KC), and monocyte chemoattractant protein-1 (MCP-1) were elevated (p<0.01, or p<0.05). Expression of p38 and pp38 increased in the intestine (p<0.01, or p<0.05). CB1-/- mice showed an increased inflammatory response during POI, especially the systemic inflammatory markers, such as IL-6, KC, CINC1, and pp38 expression were increased as compared to those in WT mice (p<0.05).
Intestinal motility was inhibited during POI. In this condition, inhibition of motility did not seem to be altered by the absence of CB1 receptors, however, an increased inflammatory response was observed in CB1-/- mice. Hence, CB1 receptor activation rather than inhibition may reduce the inflammatory response in POI, which has a remote potential to relate into reduced inhibition of intestinal motility during POI.
PLoS ONE 07/2013; 8(7):e67427. DOI:10.1371/journal.pone.0067427 · 3.23 Impact Factor
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