Identification of TNF-alpha-responsive NF-kappaB p65-binding element in the distal promoter of the mouse serine protease inhibitor SerpinE2

Agomelatine prevents indomethacin-induced gastric ulcer in rats

BACKGROUND

Gastric ulcer is a very common gastrointestinal disease that may be dangerous and even may lead to death. The current study was conducted to detect the prophylactic effects of agomelatine on indomethacin-induced gastric ulcer.

METHODS

In this study, a total of 5 groups were created as the sham, ulcer, omeprazole, agomelatine 1 mg/kg and agomelatine 5 mg/kg groups. The effects of agomelatine on indomethacin-induced gastric injury were investigated. Total antioxidant and oxidant levels; the oxidant parameters like oxidative stress index and the inflammation markers such as tumor necrosis factor-α, interleukin-1β, interleukin-6 and interleukin-10 levels in stomach tissue were determined by ELISA. In addition, the gastric mucosal injury occurred in stomach wall was examined with histopathological methods.

RESULTS

While the levels of the inflammatory markers, total oxidant status and oxidative stress index increased at an obvious level especially in the indomethacin group, the total antioxidant status levels decreased. It was observed that these parameters were improved at a significant level in agomelatine 1 mg/kg and agomelatine 5 mg/kg groups when compared to ulcer group; and the results were similar to omeprazole group. It was also observed that our histopathological findings were consistent with all our other results.

CONCLUSIONS

The results of this study showed that agomelatine usage in indomethacin-induced gastric ulcer model provides beneficial results.

Cistrome-based Cooperation between Airway Epithelial Glucocorticoid Receptor and NF-κB Orchestrates Anti-inflammatory Effects

Antagonism of pro-inflammatory transcription factors by monomeric glucocorticoid receptor (GR) has long been viewed as central to glucocorticoid (GC) efficacy. However, the mechanisms and targets through which GCs exert therapeutic effects in diseases such as asthma remain incompletely understood. We previously defined a surprising cooperative interaction between GR and NF-κB that enhanced expression of A20 (TNFAIP3), a potent inhibitor of NF-κB. Here we extend this observation to establish that A20 is required for maximal cytokine repression by GCs. To ascertain the global extent of GR and NF-κB cooperation, we determined genome-wide occupancy of GR, the p65 subunit of NF-κB, and RNA polymerase II in airway epithelial cells treated with dexamethasone, TNF, or both using chromatin immunoprecipitation followed by deep sequencing. We found that GR recruits p65 to dimeric GR binding sites across the genome and discovered additional regulatory elements in which GR-p65 cooperation augments gene expression. GR targets regulated by this mechanism include key anti-inflammatory and injury response genes such as SERPINA1, which encodes α1 antitrypsin, and FOXP4, an inhibitor of mucus production. Although dexamethasone treatment reduced RNA polymerase II occupancy of TNF targets such as IL8 and TNFAIP2, we were unable to correlate specific binding sequences for GR or occupancy patterns with repressive effects on transcription. Our results suggest that cooperative anti-inflammatory gene regulation by GR and p65 contributes to GC efficacy, whereas tethering interactions between GR and p65 are not universally required for GC-based gene repression.

Allelic expression mapping across cellular lineages to establish impact of non-coding SNPs

Most complex disease-associated genetic variants are located in non-coding regions and are therefore thought to be regulatory in nature. Association mapping of differential allelic expression (AE) is a powerful method to identify SNPs with direct cis-regulatory impact (cis-rSNPs). We used AE mapping to identify cis-rSNPs regulating gene expression in 55 and 63 HapMap lymphoblastoid cell lines from a Caucasian and an African population, respectively, 70 fibroblast cell lines, and 188 purified monocyte samples and found 40–60% of these cis-rSNPs to be shared across cell types. We uncover a new class of cis-rSNPs, which disrupt footprint-derived de novo motifs that are predominantly bound by repressive factors and are implicated in disease susceptibility through overlaps with GWAS SNPs. Finally, we provide the proof-of-principle for a new approach for genome-wide functional validation of transcription factor–SNP interactions. By perturbing NFκB action in lymphoblasts, we identified 489 cis-regulated transcripts with altered AE after NFκB perturbation. Altogether, we perform a comprehensive analysis of cis-variation in four cell populations and provide new tools for the identification of functional variants associated to complex diseases.

Activation of NF-kappaB by extracellular S100A4: analysis of signal transduction mechanisms and identification of target genes

The metastasis-promoting protein S100A4 stimulates metastatic progression through both intracellular and extracellular functions. Extracellular activities of S100A4 include stimulation of angiogenesis, regulation of cell death and increased cell motility and invasion, but the exact molecular mechanisms by which extracellular S100A4 exerts these effects are incompletely elucidated. The aim of the present study was to characterize S100A4-induced signal transduction mechanisms and to identify S100A4 target genes. We demonstrate that extracellular S100A4 activates the transcription factor NF-kappaB in a subset of human cancer cell lines through induction of phosphorylation and subsequent degradation of the NF-kappaB inhibitor IkappaBalpha. Concomitantly, S100A4 induced a sustained activation of the MAP kinase JNK, whereas no increased activity of the MAP kinases p38 or ERK was observed. Microarray analyses identified 136 genes as being significantly regulated by S100A4 treatment, and potentially interesting S100A4-induced gene products include IkappaBalpha, p53, ephrin-A1 and optineurin. Increased expression of ephrin-A1 and optineurin was validated using RT-PCR, Western blotting and functional assays. Furthermore, S100A4-stimulated transcription of these target genes was dependent on activation of the NF-kappaB pathway. In conclusion, these findings contribute to the understanding of the complex molecular mechanisms responsible for the diverse biological functions of extracellular S100A4, and provide further evidence of how S100A4 may stimulate metastatic progression.

Induction of TNF-alpha by LPS in Schwann cell is regulated by MAPK activation signals

Mitogen-activated protein kinases (MAPKs) are important mediators of cytokine expression and are critically involved in the immune response. The lipopolysaccharide (LPS) of gram-negative bacteria induces the expression of cytokines and proinflammatory genes via the toll-like receptor 4 (TLR4) signaling pathway in diverse cell types. In vivo, Schwann cells (SCs) at the site of injury may also produce tumor necrosis factor-- alpha (TNF-alpha). However, the precise mechanisms of TNF-alpha synthesis are still not clear. The purpose of the present study was to elucidate the underlying molecular mechanisms in the cultured SCs for its ability to activate the MAPKs and TNF-alpha gene, in response to LPS. Using enzyme-linked immunosorbent assay (ELISA), it was confirmed that treatment with LPS stimulated the synthesis of TNF-alpha in a concentration- and time-dependent manner. Intracellular location of TNF-alpha was detected under confocal microscope. Moreover, LPS activated extracellular signal-regulated kinase (ERK1/2), P38 and stress activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and induced their phosphorylation. LPS-elicited SCs TNF-alpha production was also drastically suppressed by PD98059 (ERK inhibitor), SB202190 (P38 inhibitor), or SP600125 (SAPK/JNK inhibitor). Additionally, the expression of CD14 and TLR4 was examined by RT-PCR. It was demonstrated that the expression of CD14, TLR4 was crucial for the SCs responses to LPS. In conclusion, the results provide novel mechanisms for the response of SCs to LPS stimulation, through MAPKs signaling pathways.