MAPK signaling pathways regulate IL-8 mRNA stability and IL-8 protein expression in cystic fibrosis lung epithelial cell lines

Cystic fibrosis (CF) is characterized by a massive proinflammatory phenotype in the lung, caused by mutations in the CFTR gene. IL-8 and other proinflammatory mediators are elevated in the CF airway, and the immediate mechanism may depend on disease-specific stabilization of IL-8 mRNA in CF lung epithelial cells. MAPK signaling pathways impact directly on IL-8 protein expression in CF cells, and we have hypothesized that the mechanism may also involve stabilization of the IL-8 mRNA. To test this hypothesis, we have examined the effects of pharmacological and molecular inhibitors of p38, and downstream MK2, ERK1/2, and JNK, on stability of IL-8 mRNA in CF lung epithelial cells. We previously showed that tristetraprolin (TTP) was constitutively low in CF and that raising TTP destabilized the IL-8 mRNA. We therefore also tested these effects on CF lung epithelial cells stably expressing TTP. TTP binds to AU-rich elements in the 3′-UTR of the IL-8 mRNA. We find that inhibition of p38 and ERK1/2 reduces the stability of IL-8 mRNA in parental CF cells. However, neither intervention further lowers TTP-dependent destabilization of IL-8 mRNA. By contrast, inhibition of the JNK-2 pathway has no effect on IL-8 mRNA stability in parental CF cell, but rather increases the stability of the message in cells expressing high levels of TTP. However, we find that inhibition of ERK1/2 or p38 leads to suppression of the effect of JNK-2 inhibition on IL-8 mRNA stability. These data thus lend support to our hypothesis that constitutive MAPK signaling and proteasomal activity might also contribute, along with aberrantly lower TTP, to the proinflammatory phenotype in CF lung epithelial cells by increasing IL-8 mRNA stability and IL-8 protein expression.

Download Full-text

Tristetraprolin regulates IL-8 mRNA stability in cystic fibrosis lung epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.90601.2008 ◽

2009 ◽

Vol 296 (6) ◽

pp. L1012-L1018 ◽

Cited By ~ 27

Author(s):

Nagaraja Sethuraman Balakathiresan ◽

Sharmistha Bhattacharyya ◽

Usha Gutti ◽

Robert P. Long ◽

Catherine Jozwik ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Mrna Stability ◽

Posttranscriptional Regulation ◽

Lung Epithelial Cells ◽

Cellular Phenotype ◽

Lung Epithelial ◽

Vitro Analysis ◽

In Vitro Analysis

Cystic fibrosis (CF) is due to mutations in the CFTR gene and is characterized by hypersecretion of the proinflammatory chemokine IL-8 into the airway lumen. Consequently, this induces the highly inflammatory cellular phenotype typical of CF. Our initial studies revealed that IL-8 mRNA is relatively stable in CF cells compared with those that had been repaired with [WT]CFTR (wild-type CFTR). Relevantly, the 3′-UTR of IL-8 mRNA contains AU-rich sequences (AREs) that have been shown to mediate posttranscriptional regulation of proinflammatory genes upon binding to ARE-binding proteins including Tristetraprolin (TTP). We therefore hypothesized that very low endogenous levels of TTP in CF cells might be responsible for the relative stability of IL-8 mRNA. As predicted, increased expression of TTP in CF cells resulted in reduced stability of IL-8 mRNA. An in vitro analysis of IL-8 mRNA stability in CF cells also revealed a TTP-induced enhancement of deadenylation causing reduction of IL-8 mRNA stability. We conclude that enhanced stability of IL-8 mRNA in TTP-deficient CF lung epithelial cells serve to drive the proinflammatory cellular phenotype in the CF lung.

Download Full-text

Nitric oxide increases IL-8 gene transcription and mRNA stability to enhance IL-8 gene expression in lung epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00165.2004 ◽

2004 ◽

Vol 287 (4) ◽

pp. L764-L773 ◽

Cited By ~ 34

Author(s):

Loretta Sparkman ◽

Vijayakumar Boggaram

Keyword(s):

Gene Expression ◽

Nitric Oxide ◽

Protein Kinase ◽

Epithelial Cells ◽

Gene Transcription ◽

Mrna Stability ◽

Inflammatory Responses ◽

Lung Epithelial Cells ◽

Mrna Levels ◽

Lung Epithelial

Interleukin (IL)-8, a C-X-C chemokine, is a potent chemoattractant and an activator for neutrophils, T cells, and other immune cells. The airway and respiratory epithelia play important roles in the initiation and modulation of inflammatory responses via production of cytokines and surfactant. The association between elevated levels of nitric oxide (NO) and IL-8 in acute lung injury associated with sepsis, acute respiratory distress syndrome, respiratory syncytial virus infection in infants, and other inflammatory diseases suggested that NO may play important roles in the control of IL-8 gene expression in the lung. We investigated the role of NO in the control of IL-8 gene expression in H441 lung epithelial cells. We found that a variety of NO donors significantly induced IL-8 mRNA levels, and the increase in IL-8 mRNA was associated with an increase in IL-8 protein. NO induction of IL-8 mRNA was due to increases in IL-8 gene transcription and mRNA stability. NO induction of IL-8 mRNA levels was not inhibited by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and KT-5823, inhibitors of soluble guanylate cyclase and protein kinase G, respectively, and 8-bromo-cGMP did not increase IL-8 mRNA levels. This indicated that NO induces IL-8 mRNA levels independently of changes in the intracellular cGMP levels. NO induction of IL-8 mRNA was significantly reduced by inhibitors of extracellular regulated kinase and protein kinase C. IL-8 induction by NO was also reduced by hydroxyl radical scavengers such as dimethyl sulfoxide and dimethylthiourea, indicating the involvement of hydroxyl radicals in the induction process. NO induction of IL-8 gene expression could be a significant contributing factor in the initiation and induction of inflammatory response in the respiratory epithelium.

Download Full-text

Immune Defense Protein Expression in Highly Purified Mouse Lung Epithelial Cells

American Journal of Respiratory Cell and Molecular Biology ◽

10.1165/rcmb.2015-0171oc ◽

2016 ◽

Vol 54 (6) ◽

pp. 802-813 ◽

Cited By ~ 9

Author(s):

Meenal Sinha ◽

Clifford A. Lowell

Keyword(s):

Epithelial Cells ◽

Protein Expression ◽

Immune Defense ◽

Lung Epithelial Cells ◽

Mouse Lung ◽

Lung Epithelial ◽

Defense Protein

Download Full-text

Urokinase Receptor mRNA Stability Involves Tyrosine Phosphorylation in Lung Epithelial Cells

American Journal of Respiratory Cell and Molecular Biology ◽

10.1165/rcmb.2002-0305oc ◽

2004 ◽

Vol 30 (1) ◽

pp. 69-75 ◽

Cited By ~ 12

Author(s):

Sreerama Shetty ◽

Steven Idell

Keyword(s):

Epithelial Cells ◽

Tyrosine Phosphorylation ◽

Mrna Stability ◽

Urokinase Receptor ◽

Lung Epithelial Cells ◽

Receptor Mrna ◽

Lung Epithelial

Download Full-text

Berberine inhibits lipopolysaccharide-induced expression of inflammatory cytokines by suppressing TLR4-mediated NF-ĸB and MAPK signaling pathways in rumen epithelial cells of Holstein calves

Journal of Dairy Research ◽

10.1017/s0022029919000323 ◽

2019 ◽

Vol 86 (2) ◽

pp. 171-176 ◽

Cited By ~ 8

Author(s):

Chenxu Zhao ◽

Yazhou Wang ◽

Xue Yuan ◽

Guoquan Sun ◽

Bingyu Shen ◽

...

Keyword(s):

Epithelial Cells ◽

Signaling Pathways ◽

Inflammatory Cytokines ◽

Molecular Mechanisms ◽

Mapk Signaling ◽

Dependent Manner ◽

Inflammatory Drug ◽

Anti Inflammatory ◽

Mapk Signaling Pathways ◽

Rumen Epithelial Cells

AbstractSubacute ruminal acidosis (SARA) can increase the level of inflammation and induce rumenitis in dairy cows. Berberine (BBR) is the major active component of Rhizoma Coptidis, which is a type of Chinese anti-inflammatory drug for gastrointestinal diseases. The purpose of this study was to investigate the anti-inflammatory effects of BBR on lipopolysaccharide (LPS)-stimulated rumen epithelial cells (REC) and the underlying molecular mechanisms. REC were cultured and stimulated with LPS in the presence or absence of different concentrations of BBR. The results showed that cell viability was not affected by BBR. Moreover, BBR markedly decreased the concentrations and mRNA expression of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, and interleukin-6 in the LPS-treated REC in a dose-dependent manner. Importantly, Western blotting analysis showed that BBR significantly suppressed the protein expression of toll-like receptor 4 (TLR4) and myeloid differentiation primary response protein (MyD88) and the phosphorylation of nuclear factor-κB (NF-κB), inhibitory kappa B (IκBα), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) in LPS-treated REC. Furthermore, the results of immunocytofluorescence showed that BBR significantly inhibited the nuclear translocation of NF-κB p65 induced by LPS treatment. In conclusion, the protective effects of BBR on LPS-induced inflammatory responses in REC may be due to its ability to suppress the TLR4-mediated NF-κB and MAPK signaling pathways. These findings suggest that BBR can be used as an anti-inflammatory drug to treat inflammation induced by SARA.

Download Full-text