scholarly journals Increased intracellular Ca2+ selectively suppresses IL-1-induced NO production by reducing iNOS mRNA stability.

1995 ◽  
Vol 129 (6) ◽  
pp. 1651-1657 ◽  
Author(s):  
Y Geng ◽  
M Lotz

This study addresses the role of intracellular calcium (Ca2+) in the expression of iNOS, an IL-1 inducible gene in human articular chondrocytes. The calcium ionophore A23187 and ionomycin did not induce NO release or iNOS expression but inhibited dose dependently IL-1-induced NO release with IC50 of 200 nM and 100 nM, respectively. Increased intracellular Ca2+ induced by thapsigargin or cyclopiazonic acid, inhibitors of the endoplasmic reticulum Ca2+ ATPase, had similar inhibitory effects with IC50 of 1 nM and 3 microM, respectively. LPS and TNF alpha induced NO production were also suppressed by these Ca2+ elevating drugs. Levels of IL-1-induced iNOS protein were reduced by A23187, thapsigargin, and cyclopiazonic acid. These drugs as well as Bay K 8644 and KCl inhibited IL-1-induced iNOS mRNA expression. To analyze the role of Ca2+ in the expression of other IL-1 responsive genes in chondrocytes, these Ca2+ modulating drugs were tested for effects on COXII. In contrast to the inhibitory effects on iNOS mRNA, these drugs induced COXII mRNA expression and in combination with IL-1, enhanced COXII mRNA levels. Ca2+ mediated increases in COXII mRNA expression were associated with an increase in COXII protein. The kinetics of Ca2+ effects on IL-1-induced iNOS mRNA levels suggested a posttranscriptional mechanism. Analysis of iNOS mRNA half life showed that it was 6-7 h in IL-1-stimulated cells and decreased by A23187 to 2-3 h. In conclusion, these results show that Ca2+ inhibits IL-1-induced NO release, iNOS protein, and mRNA expression in human articular chondrocytes by reducing iNOS mRNA stability. Under identical conditions increased Ca2+ enhances IL-1-induced COXII gene and protein expression.

2011 ◽  
Vol 22 (19) ◽  
pp. 3625-3633 ◽  
Author(s):  
Agnès Desroches-Castan ◽  
Nadia Cherradi ◽  
Jean-Jacques Feige ◽  
Delphine Ciais

Tis11b/BRF1 belongs to the tristetraprolin family, the members of which are involved in AU-rich-dependent regulation of mRNA stability/degradation. Mouse inactivation of the Tis11b gene has revealed disorganization of the vascular network and up-regulation of the proangiogenic factor VEGF. However, the VEGF deregulation alone cannot explain the phenotype of Tis11b knockouts. Therefore we investigated the role of Tis11b in expression of Dll4, another angiogenic gene for which haploinsufficiency is lethal. In this paper, we show that Tis11b silencing in endothelial cells leads to up-regulation of Dll4 protein and mRNA expressions, indicating that Dll4 is a physiological target of Tis11b. Tis11b protein binds to endogenous Dll4 mRNA, and represses mRNA expression without affecting its stability. In the Dll4 mRNA 3′ untranslated region, we identified one particular AUUUA motif embedded in a weak noncanonical polyadenylation (poly(A)) signal as the major Tis11b-binding site. Moreover, we observed that inhibition of Tis11b expression changes the ratio between mRNAs that are cleaved or read through at the poly(A) signal position, suggesting that Tis11b can interfere with mRNA cleavage and poly(A) efficiency. Last, we report that this Tis11b-mediated mechanism is used by endothelial cells under hypoxia for controlling Dll4 mRNA levels. This work constitutes the first description of a new function for Tis11b in mammalian cell mRNA 3′-end maturation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haidy A. Saleh ◽  
Eman Ramdan ◽  
Mohey M. Elmazar ◽  
Hassan M. E. Azzazy ◽  
Anwar Abdelnaser

AbstractDoxorubicin (DOX) chemotherapy is associated with the release of inflammatory cytokines from macrophages. This has been suggested to be, in part, due to DOX-mediated leakage of endotoxins from gut microflora, which activate Toll-like receptor 4 (TLR4) signaling in macrophages, causing severe inflammation. However, the direct function of DOX on macrophages is still unknown. In the present study, we tested the hypothesis that DOX alone is incapable of stimulating inflammatory response in macrophages. Then, we compared the anti-inflammatory effects of curcumin (CUR), resveratrol (RES) and sulforaphane (SFN) against lipopolysaccharide/interferon-gamma (LPS/IFN-γ)-mediated inflammation in the absence or presence of DOX. For this purpose, RAW 264.7 cells were stimulated with LPS/IFN-γ (10 ng/mL/10 U/mL) in the absence or presence of DOX (0.1 µM). Our results showed that DOX alone is incapable of stimulating an inflammatory response in RAW 264.7 macrophages. Furthermore, after 24 h of incubation with LPS/IFN-γ, a significant increase in tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS) mRNA levels was observed. Similarly, nitric oxide (NO) production and TNF-α and IL-6 protein levels were significantly upregulated. Moreover, in LPS/IFN-γ-treated macrophages, the microRNAs (miRNAs) miR-146a, miR-155, and miR-21 were significantly overexpressed. Interestingly, upon testing CUR, RES, and SFN against LPS/IFN-γ-mediated inflammation, only SFN was able to significantly reverse the LPS/IFN-γ-mediated induction of iNOS, TNF-α and IL-6 and attenuate miR-146a and miR-155 levels. In conclusion, SFN, at the transcriptional and posttranscriptional levels, exhibits potent immunomodulatory action against LPS/IFN-γ-stimulated macrophages, which may indicate SFN as a potential treatment for DOX-associated inflammation.


Epigenomics ◽  
2021 ◽  
Author(s):  
Beatriz Garcia-Ruiz ◽  
Manuel Castro de Moura ◽  
Gerard Muntané ◽  
Lourdes Martorell ◽  
Elena Bosch ◽  
...  

Aim: To investigate DDR1 methylation in the brains of bipolar disorder (BD) patients and its association with DDR1 mRNA levels and comethylation with myelin genes. Materials & methods: Genome-wide profiling of DNA methylation (Infinium MethylationEPIC BeadChip) corrected for glial composition and DDR1 gene expression analysis in the occipital cortices of individuals with BD (n = 15) and healthy controls (n = 15) were conducted. Results: DDR1 5-methylcytosine levels were increased and directly associated with DDR1b mRNA expression in the brains of BD patients. We also observed that DDR1 was comethylated with a group of myelin genes. Conclusion: DDR1 is hypermethylated in BD brain tissue and is associated with isoform expression. Additionally, DDR1 comethylation with myelin genes supports the role of this receptor in myelination.


2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 20030-20030
Author(s):  
M. B. Pinho ◽  
J. Sellos ◽  
F. Costas ◽  
D. Herchenhorn ◽  
F. A. Peixoto ◽  
...  

20030 Background: The relation between apoptosis-related molecules and chemosensitivity has been extensively studied. In recent years, attention has shifted to a new family of inhibitor of apoptosis proteins (IAPs). XIAP (X- linked inhibitor of apoptosis) is the most versatile and potent member of the IAP family. To date, the overexpression of XIAP has been detected in various cancers. XAF1 (X-linked inhibitor of apoptosis associated factor 1) is a new protein identified for its ability to interact with XIAP. Neither XIAP nor XAF1 or XIAP/XAF1 mRNA expression have been studied in bladder cancer patients. Methods: The expression of XIAP and XAF1 mRNA was analyzed by a real time quantitative fluorogenic PCR method in a group of 17 patients with locally advanced bladder cancer treated with a combination of neoadjuvant Gemcitabine and Cisplatin. The prognostic significance of XIAP and XAF1 mRNA expression and the correlation with several clinicopathological variables was evaluated. Results: XIAP and XAF1 mRNA expression was detected in all 17 (100%) case samples. The levels of XIAP mRNA expression showed a moderate variation among samples. In contrast, XAF1 and XIAP/XAF1 mRNA levels showed significant variation among samples. Bivariate correlation analyses revealed a significant positive Spearman direct correlation coefficient between the XIAP expression and the pathological response. No significant correlation was found for XAF1 expression as well as for the XIAP/XAF1 ratio and clinical and pathological response. Conclusions: This is first study to address the role of XIAP, its negative regulator XAF1, and the XIAP/XAF1 ratio in bladder cancer patients. The positive correlation between the XIAP mRNA expression and the pathological response is in line with a previous study from our group in which a correlation was found between XIAP expression and survival. All these observations point to a complex role of XIAP in tumor biology. XAF1 mRNA expression in bladder carcinomas did not achieve significance as an independent predictive and prognostic factor in a bivariate analysis. Further studies are necessary in order to better assess a possible clinical value for XIAP and XAF1 as predictive and prognostic markers in cancer patients. No significant financial relationships to disclose.


2002 ◽  
Vol 282 (2) ◽  
pp. R623-R626 ◽  
Author(s):  
Kazue Kikuchi-Utsumi ◽  
Bihu Gao ◽  
Hiroshi Ohinata ◽  
Masaaki Hashimoto ◽  
Noriyuki Yamamoto ◽  
...  

It has been shown that norepinephrine (NE) can mediate vasodilatation by stimulating the production of nitric oxide (NO) in brown adipose tissue (BAT), resulting in an increase in BAT blood flow. We speculated that constitutive NO synthase (NOS) is involved in this NO production. However, it is not known whether constitutive NOS is expressed in BAT. To answer this question, we assessed the expression of two types of constitutive NOS, endothelial (eNOS) and neuronal NOS (nNOS), in BAT of rats. eNOS was abundantly expressed in both BAT and isolated brown adipocytes, whereas nNOS was not. Cold exposure, which is known to stimulate NE release from sympathetic nerve terminals in BAT, led to a significant increase in eNOS mRNA in this tissue. In contrast, very low levels of inducible NOS (iNOS) mRNA were expressed, and cold stimulation failed to increase iNOS mRNA levels in BAT. These results suggest that eNOS is the primary isoform that is responsible for NO production in BAT and that its expression may be under sympathetic control.


1990 ◽  
Vol 171 (4) ◽  
pp. 1269-1281 ◽  
Author(s):  
M J Smyth ◽  
J R Ortaldo ◽  
Y Shinkai ◽  
H Yagita ◽  
M Nakata ◽  
...  

Our studies have analyzed pore-forming protein (PFP) mRNA expression in resting and stimulated human peripheral blood CD3- large granular lymphocytes (LGL), CD3+ T cells, and their CD4+ or CD8+ subsets. Signals that stimulate T cells to develop cytotoxic activity (i.e., IL-2 or OKT-3 mAb) led to the induction of PFP mRNA in T cells. The data indicated that IL-2 directly increased PFP mRNA in the CD8+ subset of T cells, in the absence of new DNA or protein synthesis. Abrogation of IL-2-induced PFP mRNA expression and cytotoxic potential of T cells by the anti-p75 IL-2 receptor mAb suggested that low numbers of p75 IL-2 receptors on CD8+ T cells were capable of transducing signals responsible for these IL-2-induced effects. The induction of T cell PFP mRNA via CD3, using OKT-3 mAb, was less rapid but greater than that caused by IL-2; however, a combination of PMA and ionomycin, which bypasses crosslinking of the TCR/CD3 complex, could not mimic this increase in PFP mRNA levels in T cells. The role of second messenger systems in regulating PFP mRNA expression remains to be determined. In contrast, high constitutive PFP mRNA expression was observed in CD3- LGL and these mRNA levels could not be enhanced by stimulation with IL-2. The cytotoxic potential of peripheral blood T cells and LGL induced in response to IL-2 correlated with IL-2-induced PFP mRNA levels in these cells and was consistent with PFP being one of several important molecules involved in the effector function of cytotoxic lymphocytes.


2006 ◽  
Vol 291 (1) ◽  
pp. G35-G44 ◽  
Author(s):  
Tamer Ahmed ◽  
Gladys Yumet ◽  
Margaret Shumate ◽  
Charles H. Lang ◽  
Peter Rotwein ◽  
...  

Growth hormone (GH) stimulates STAT5 phosphorylation by JAK2, which activates IGF-I and serine protease inhibitor 2.1 (Spi 2.1) transcription, whereas STAT5 dephosphorylation by protein tyrosine phosphatases (PTPs) terminates this signal. We hypothesized that the inhibitory effects of TNF on GH signaling and gene transcription were responsible for hepatic GH resistance. CWSV-1 hepatocytes were treated with TNF, pervanadate (a PTP inhibitor), or both, before GH stimulation. Total and tyrosine-phosphorylated JAK2, STAT5, ERK1/2, SHP-1 and SHP-2, IGF-I, and Spi 2.1 mRNA levels were measured. GH stimulated STAT5 and ERK1/2 phosphorylation, IGF-I, and Spi 2.1 mRNA expression. TNF attenuated JAK2/STAT5 and ERK1/2 phosphorylation and IGF-I and Spi 2.1 mRNA expression following GH stimulation. SHP-1 and SHP-2 protein levels were unaltered by TNF or GH, and the GH-induced increase in SHP-1 PTP activity was not further increased by TNF. In TNF-treated cells, pervanadate restored STAT5 and ERK1/2 phosphorylation to control levels following GH stimulation but did not restore IGF-I or Spi 2.1 mRNA induction. Cells transfected with a Spi 2.1 promoter-luciferase vector demonstrate a 50-fold induction in luciferase activity following GH stimulation or cotransfection with a constitutively active STAT5 vector. TNF prevented the induction of Spi 2.1 promoter activity by GH and the STAT5 construct. We conclude that TNF does not inhibit GH activity by inducing SHP-1 or -2 expression and that correction of GH signaling defects in TNF-treated cells by pervanadate does not restore GH-induced gene expression. The inhibitory effects of TNF on GH-mediated gene transcription appear independent of STAT5 activity and previously identified abnormalities in JAK2/STAT5 signaling.


2021 ◽  
Author(s):  
Xiansheng Huang ◽  
Yiqi Zhang ◽  
Wenqiang Zhu ◽  
Piaopiao Huang ◽  
Jingmei Xiao ◽  
...  

Olanzapine, an antipsychotic drug, was reported to induce hypertriglyceridemia, whereas the underlying mechanism remains incompletely understood. This study was to determine the role of apolipoprotein A5 (apoA5) in olanzapine-induced hypertriglyceridemia. In this study, 36 drug-naive and first-episode schizophrenic adult patients (aged 18-60 years) in a multi-center clinical trial (ClinicalTrials.gov NCT03451734) were enrolled. Before and after olanzapine treatment, plasma lipid and apoA5 levels were detected. Moreover, 21 female C57BL/6 J mice (8 weeks old) were divided into 3 groups (n = 7/each group): low-dose olanzapine (3 mg/kg/day), high-dose olanzapine (6 mg/kg/day) and control group. After 6 weeks, plasma glucose, lipids and apoA5 as well as hepatic apoA5 protein and mRNA expression in these animals were detected. In our study in vitro, primary mouse hepatocytes and HepG2 cells were treated with olanzapine of 25, 50, 100 μmol/L, respectively. After 24 hours, apoA5 protein and mRNA levels in hepatocytes were detected. Our study showed that olanzapine treatment significantly increased plasma triglyceride levels and decreased plasma apoA5 levels in these schizophrenic patients. A significant negative correlation was indicated between plasma triglyceride and apoA5 levels in these patients. Consistently, olanzapine dose-dependently increased plasma triglyceride levels and decreased plasma apoA5 levels in mice. Surprisingly, an elevation of hepatic apoA5 protein levels was detected in mice after olanzapine treatment, with no changes of APOA5 mRNA expression. Likewise, olanzapine increased apoA5 protein levels in hepatocytes in vitro, without changes of hepatocyte APOA5 mRNA. Therefore, our study provides the first evidence about the role of apoA5 in olanzapine-induced hypertriglyceridemia. Furthermore, plasma apoA5 reduction, resulting in hypertriglyceridemia, could be attributed to olanzapine-induced inhibition of hepatic apoA5 secretion.


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