Transcriptional and post-transcriptional control of gene expression in inflammation

Regulatory effects of antioxidants on indoxyl sulfate-enhanced intracellular oxidation and impaired phagocytic activity in differentiated U937 human macrophage cells

Indoxyl sulfate (IS), a uremic toxin, is a physiologically active sulfated metabolite, specifically in kidney failure patients. Our previous studies have shown that IS downregulates phagocytic immune function in a differentiated HL-60 human macrophage cell model. However, it remains unclear whether IS exerts similar effects on macrophage function in other cell types or in lipopolysaccharide (LPS)-sensitive immune cell models. Therefore, this study aimed to investigate the effects of IS on intracellular oxidation levels and phagocytic activity in a differentiated U937 human macrophage cell model, both in the absence and presence of LPS. Our results demonstrated that IS significantly increases intracellular oxidation levels and decreases phagocytic activity, particularly in cells activated by LPS. Furthermore, we found that 2-acetylphenothiazine, an NADH oxidase inhibitor, attenuates the effects of IS in LPS-activated macrophage cells. Representative antioxidants, trolox, α-tocopherol, and ascorbic acid, significantly mitigated the effects of IS on the macrophages responding to LPS.

Vitamin D and immune system

The active metabolite of vitamin D 1,25(OH)2D is well known for its role in regulating calcium-phosphate homeostasis of the human body. However, the immunomodulating activity of 1,25(OH)2D has been known for many years. There are numerous reports correlating low vitamin D levels in blood serum with the onset of autoimmune diseases and with the severe course of acute infections. In this chapter, we address the role of 1,25(OH)2D in these diseases, and we discuss the possible mechanisms of action of 1,25(OH)2D in immune cells.

Fetal inflammatory response and risk for psychiatric disorders

Inflammation contributes to numerous neuropsychiatric disorders, especially those that first appear in childhood. Maternal intrauterine environment, including the placenta, has a role in brain development and risk for neuropsychiatric disorders. This study examines the link between fetal inflammatory syndrome (FIRS), which is placental inflammation in the peri-partem period, and neuropsychiatric disorders during childhood.This is a retrospective cohort study using data from electronic medical records over a 19-year period at one women's hospital. The study includes 4851 children born with placentas meeting criteria for and 31,927 controls identified with normal placentas born during the same period. To be diagnosed with FIRS placenta must contain chorionic vasculitis and/or funisitis. Children had to be in study period for at least 5 years. The primary outcome of the study is incidence of neuropsychiatric disorders during childhood. The secondary outcomes were psychiatric medications prescribed, and psychiatric hospitalizations and treatment. Children born to placentas meeting criteria for FIRS were more likely to be diagnosed with neuropsychiatric disorders (OR = 1.21, CI 95% [1.09,1.35]). Specifically, they were more likely to be diagnosed with autism spectrum disorder (OR = 1.35, CI 95% [1.08, 1.67]), ADHD (OR = 1.27, CI 95% [1.07, 1.49]), conduct disorder (OR = 1.50, CI 95% [1.24, 1.81]), PTSD (OR = 2.46. CI 95% [1.21, 5.04]), adjusting for maternal history of psychiatric disorders, intra-partem substance use, and prescriptions of anti-inflammatory drugs. Children born with placental inflammation are at an increased risk to develop neuropsychiatric disorders. This has profound implications for future research, and early detection, monitoring, and treatment in these children.

The forgotten key players in rheumatoid arthritis: IL-8 and IL-17 - Unmet needs and therapeutic perspectives

Despite the relevant advances in our understanding of the pathogenetic mechanisms regulating inflammation in rheumatoid arthritis (RA) and the development of effective therapeutics, to date, there is still a proportion of patients with RA who do not respond to treatment and end up progressing toward the development of joint damage, extra-articular complications, and disability. This is mainly due to the inter-individual heterogeneity of the molecular and cellular taxonomy of the synovial membrane, which represents the target tissue of RA inflammation. Tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) are crucial key players in RA pathogenesis fueling the inflammatory cascade, as supported by experimental evidence derived from in vivo animal models and the effectiveness of biologic-Disease Modifying Anti-Rheumatic Drugs (b-DMARDs) in patients with RA. However, additional inflammatory soluble mediators such as IL-8 and IL-17 exert their pathogenetic actions promoting the detrimental activation of immune and stromal cells in RA synovial membrane, tendons, and extra-articular sites, as well as blood vessels and lungs, causing extra-articular complications, which might be excluded by the action of anti-TNFα and anti-IL6R targeted therapies. In this narrative review, we will discuss the role of IL-8 and IL-17 in promoting inflammation in multiple biological compartments (i.e., synovial membrane, blood vessels, and lung, respectively) in animal models of arthritis and patients with RA and how their selective targeting could improve the management of treatment resistance in patients.

Anti-inflammatory evaluation of Scurrula ferruginea (jack) danser parasitizing on Tecoma stans (L.) H.B.K. in LPS/IFN-γ-induced RAW 264.7 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Scurrula ferruginea (Jack) Danser (locally known as 'Dedalu' or 'dian nan ji sheng' in Malaysia and China) is a hemi-parasitic shrub that is widely used as herbal medicine to treat inflammation, rheumatism, and stroke. However, the scientific basis of its anti-inflammatory function and mechanism remain to be proven.

AIM OF THE STUDY

To evaluate the anti-inflammatory activity as well as the preliminary mechanism of S. ferruginea parasitizing on Tecoma stans.

MATERIALS AND METHODS

The anti-inflammatory capability of freeze-dried stem aqueous extract was assessed via inhibition of inflammatory cytokines interleukin- (IL-) 1β, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α) production in lipopolysaccharide (LPS) and interferon-γ (IFN-γ) stimulated RAW 264.7 macrophages. The underlying anti-inflammatory mechanism was deciphered through reverse transcriptase and real time quantitative polymerase chain reactions (RT-PCR and qPCR) for inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), IL-1β, and TNF-α mRNA expression.

RESULTS

The results exhibited that aqueous extract of freeze-dried S. ferruginea stem sample concentration-dependently inhibited IL-1β protein production along with the down regulation of iNOS and IL-1β mRNA expression. Moreover, it significantly suppressed the protein release of IL-6 and IL-10 in a concentration-dependent manner. However, it slightly reduced TNF-α at higher sample concentration (250 μg/mL) without affecting the mRNA expression levels of COX-2 and TNF-α.

CONCLUSIONS

This study suggests that S. ferruginea parasitizing on Tecoma stans exerted anti-inflammatory capability attributed to inhibition of iNOS and IL-1β mRNA expression, NO creation, IL-1β, IL-6, IL-10, and TNF-α protein production, indicating this plant might be a useful plant-derived candidate against inflammation.

Water extract of Artemisia scoparia Waldst. & Kitam suppresses LPS-induced cytokine production and NLRP3 inflammasome activation in macrophages and alleviates carrageenan-induced acute inflammation in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia scoparia Waldst. & Kitam (A. scoparia) is a perennial herbal plant that is widely used as a folk remedy in Asian countries. Several studies have demonstrated that A. scoparia has various physiological effects, including anti-inflammation, anti-hypertension, anti-obesity, anti-hepatotoxicity, and anti-oxidant effects.

AIM OF THE STUDY

The objective of the present study was to examine the anti-inflammatory effects of water extract of A. scoparia (WAS).

MATERIALS AND METHODS

Murine bone marrow-derived macrophages (BMDMs), human monocyte THP-1 and murine fibroblast 3T3-L1 cells were used for the in vitro experiments. Cell viability and cytokine production were determined by the MTT assay and ELISA, respectively. RT-PCR was performed to determine iNOS gene expression and the Griess reaction was used to measure nitrite levels. iNOS protein expression, activation of NF-κB and MAPKs, and cleavage of caspase-1 and IL-1β were determined by Western blot analysis. A carrageenan-induced mouse model of acute inflammation was used in the in vivo experiments.

RESULTS

Pretreatment with WAS concentration-dependently suppressed gene expression and IL-6, TNF-α, CXCL1 and iNOS protein levels in BMDMs stimulated with LPS. In addition, pretreatment with WAS inhibited LPS-induced production of IL-6 and TNF-α in THP-1 cells and CXCL1 in 3T3-L1. Furthermore, LPS induced phosphorylation of p65 in BMDMs, and this induction was dramatically suppressed by WAS pretreatment. We further investigated whether WAS regulates activation of the NLRP3 inflammasome, which is known to be essential for IL-1β processing. WAS inhibited the production of IL-1β, but not IL-6, in response to adenosine triphosphate (ATP) and monosodium uric acid (MSU) crystals in LPS-primed BMDMs. Cleavage of caspase-1 and IL-1β was also reduced by WAS. We finally evaluated the in vivo anti-inflammatory effects of WAS in a mouse model of carrageenan-induced acute inflammation. Subcutaneous administration of WAS reduced production of the inflammatory cytokines IL-6, TNF-α, CXCL1, and IL-1β. Recruitment of immune cells, mostly neutrophils, was also reduced by administration of WAS. Infiltration of inflammatory cells and edema in the submucosa of air pouch tissues were markedly improved in the WAS-treated groups.

CONCLUSIONS

Our results indicate that WAS possesses potent anti-inflammatory properties. These findings suggest that A. scoparia is a candidate functional food targeting several inflammatory diseases.

RNA-binding proteins La and HuR cooperatively modulate translation repression of PDCD4 mRNA

Posttranscriptional regulation of gene expression plays a critical role in controlling the inflammatory response. An uncontrolled inflammatory response results in chronic inflammation, often leading to tumorigenesis. Programmed cell death 4 (PDCD4) is a proinflammatory tumor-suppressor gene which helps to prevent the transition from chronic inflammation to cancer. PDCD4 mRNA translation is regulated by an interplay between the oncogenic microRNA miR-21 and the RNA-binding protein (RBP) human antigen R (HuR) in response to lipopolysaccharide stimulation, but the role of other regulatory factors remains unknown. Here, we report that the RBP lupus antigen (La) interacts with the 3'-untranslated region of PDCD4 mRNA and prevents miR-21-mediated translation repression. While lipopolysaccharide causes nuclear-cytoplasmic translocation of HuR, it enhances cellular La expression. Remarkably, La and HuR were found to bind cooperatively to the PDCD4 mRNA and mitigate miR-21-mediated translation repression. The cooperative action of La and HuR reduced cell proliferation and enhanced apoptosis, reversing the pro-oncogenic function of miR-21. Together, these observations demonstrate a cooperative interplay between two RBPs, triggered differentially by the same stimulus, which exerts a synergistic effect on PDCD4 expression and thereby helps maintain a balance between inflammation and tumorigenesis.

Amino Acids in Cell Signaling: Regulation and Function

Amino acids are the main building blocks for life. Aside from their roles in composing proteins, functional amino acids and their metabolites play regulatory roles in key metabolic cascades, gene expressions, and cell-to-cell communication via a variety of cell signaling pathways. These metabolic networks are necessary for maintenance, growth, reproduction, and immunity in humans and animals. These amino acids include, but are not limited to, arginine, glutamine, glutamate, glycine, leucine, proline, and tryptophan. We will discuss these functional amino acids in cell signaling pathways in mammals with a particular emphasis on mTORC1, AMPK, and MAPK pathways for protein synthesis, nutrient sensing, and anti-inflammatory responses, as well as cell survival, growth, and development.

Effects of low dose radiation on immune cells subsets and cytokines in mice

Whole-body exposure to low-dose radiation due to diagnostic imaging procedures, occupational hazards and radiation accidents is a source of concern. In this study, we analyzed the effects of single and long-term low-dose irradiation on the immune system. Male Balb/c mice received a single whole-body dose of irradiation (0.01, 0.05, 0.2, 0.5 or 1 Gy). For long-term irradiation, mice were irradiated 10 times (total dose of 0.2, 0.5 or 1 Gy) over a period of 6 weeks. Two days after single or long-term irradiation, the numbers of splenic macrophages, natural killer cells and dendritic cells were reduced, and the spleen organ coefficient was decreased. At 2 Days after long-term low-dose irradiation, the number of white blood cells in the peripheral blood of the mice decreased. Between 7 and 14 Days after long-term low-dose irradiation, the number of immune cells in the thymus and spleen began to increase and then stabilized. Th1/Th2 cytokines and reactive oxygen species-related proteins first decreased and then increased to a plateau. Our results show a significant difference in the effects of single and long-term low-dose irradiation on the immune system.

25-vitamin D reduces inflammation in uremic environment

Chronic kidney disease (CKD) is characterized by loss of renal function and a consequent increase of serum uremic toxins, which contribute to inflammation status. Deficiency of 25-vitamin D, often found in patients with CKD, has been included as an inflammatory factor since it might modulate the immune system. The aim of this study was to investigate the role of 25-vitamin D on inflammatory pathways in healthy and uremic environment. Toll-like receptor 4 (TLR4), oxidative stress (ROS), vitamin D receptor (VDR), 1-α hydroxylase (CYP27), 24 hydroxylase, cathelicidin, and MCP-1 were evaluated in monocytes exposed to a uremic serum pool compared with healthy pool. The human monocytes lineage (U937) was incubated with or without 25-vitamin D (50 ng/ml for 24 hours). TRL4, VDR, CYP27, CYP24, and ROS were evaluated by flow cytometry. We used ELISA to measure IL-6, TNF-α, IL-10, cathelicidin, and MCP-1 in the cell culture supernatant. We observed a higher expression of TRL-4, IL-6, TNF-α, IL-10, cathelicidin and MCP-1 in monocytes incubated with uremic serum when compared with serum from healthy individuals. Supplementation of 25-vitamin D was able to reduce the expression of TRL4, cathelicidin, and MCP-1 in the uremic environment. There was no difference in the expression of VDR, CYP27 and CYP24 intracellular enzymes. This in vitro study showed that the uremic pool activates inflammatory response in monocytes, which was reversed by 25-vitamin D supplementation; this finding suggests that 25-vitamin D has an anti-inflammatory role in the uremic environment.

New 2-amino-pyridinyl-N-acylhydrazones: Synthesis and identification of their mechanism of anti-inflammatory action

AIMS

The main aim of this paper was the synthesis and the evaluation of the anti-inflammatory activity of LASSBio-1828 (an amino-pyridinyl-N-acylhydrazone) and its respective hydrochloride, based on a p38α MAPK inhibitor (LASSBio-1824) previously synthesized by our group.

MAIN METHODS

The compounds were tested regarding their cell viability effect and on acute models of inflammation such as formalin-induced licking test, cell migration and inflammatory mediators quantification.

KEY FINDINGS

Treatment with the compounds inhibited p38α, reduced inflammatory pain, cell migration and inflammatory mediators that participate on the MAPK pathway such as TNF-α and IL-1β.

SIGNIFICANCE

Taken together, these results suggest that the synthesis of the corresponding hydrochloride of LASSBio-1828 enhanced its potency as a p38 inhibitor, and also that this compound could be considered a good anti-inflammatory drug candidate after further studies.

Evolving Role of Vitamin D in Immune-Mediated Disease and Its Implications in Autoimmune Hepatitis

Vitamin D has immunomodulatory, anti-inflammatory, antioxidant, and anti-fibrotic actions that may impact on the occurrence and outcome of immune-mediated disease. The goals of this review are to describe the nature of these expanded roles, examine the implications of vitamin D deficiency in autoimmune hepatitis, and identify opportunities for future investigation. Abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Vitamin D receptors are expressed on the principal cell populations involved in the innate and adaptive immune responses. Macrophages and dendritic cells can produce 1,25-dihydroxyvitamin D within the microenvironment. This active form of vitamin D can inhibit immune cell proliferation, promote an anti-inflammatory cytokine profile, expand regulatory T cells, enhance glucocorticoid actions, increase glutathione production, and inhibit hepatic stellate cells. Vitamin D deficiency has been commonly present in patients with immune-mediated liver and non-liver diseases, and it has been associated with histological severity, advanced hepatic fibrosis, and non-response to conventional glucocorticoid therapy in autoimmune hepatitis. Vitamin D analogues with high potency, low calcemic effects, and independence from hepatic hydroxylation are possible interventions. In conclusion, vitamin D has properties that could ameliorate immune-mediated disease, and vitamin D deficiency has been a common finding in immune-mediated liver and non-liver diseases, including autoimmune hepatitis. Loss of vitamin D-dependent homeostatic mechanisms may promote disease progression. Vitamin D analogues that are independent of hepatic hydroxylation constitute an investigational opportunity to supplement current management of autoimmune hepatitis.

Mechanism of penehyclidine hydrochloride on a dysmenorrhea rat model

Primary dysmenorrhea affects the quality of life in young women, particularly school and work performance. This study investigated the mechanisms of penehyclidine hydrochloride (PHC) efficacy on a rat model of primary dysmenorrhea. The model was induced by injecting both estradiol benzoate and oxytocin. Different doses of PHC were administrated intraperitoneally following estradiol benzoate administration. Writhing scores were assessed, and pathological changes of the uterus were observed via hematoxylin and eosin staining. Western blot and real-time PCR were used to evaluate the expression level of the M₃ receptor, both TLR₃ and TLR₄ in uterine tissue, and the level of Ca²⁺ was measured in uterine tissues. Writhing scores significantly decreased in the PHC treatment group compared to model, and PHC alleviated the occurrence of edema or necrosis in the uteri compared to model group. PHC can decrease the M₃ receptor, TLR₃ , TLR₄ expression, and the Ca²⁺ level compared to the model group. PHC is a potential candidate for the future treatment of primary dysmenorrhea due to its ability to attenuate muscarinic receptors and TLRs. Preclinical Research & Development.

Z-Guggulsterone attenuates astrocytes-mediated neuroinflammation after ischemia by inhibiting toll-like receptor 4 pathway

Inflammatory damage plays a pivotal role in ischemic stroke pathogenesis and may represent one of the therapeutic targets. Z-Guggulsterone (Z-GS), an active component derived from myrrh, has been used to treat various diseases. The traditional uses suggest that myrrh is a good candidate for anti-inflammatory damage. This study was to investigate the anti-inflammatory and neuroprotective effects of Z-GS following cerebral ischemic injury, as well as the exact mechanisms behind them. Rat middle cerebral artery occlusion (MCAO) model and in vitro astrocytes oxygen-glucose deprivation (OGD) model were adopted to simulate ischemic stroke. Z-GS (30 or 60 mg/kg) was administered intraperitoneally immediately after reperfusion, while astrocytes were maintained in 30 or 60 μM Z-GS before OGD treatment. The results indicated that Z-GS significantly alleviated neurological deficits, infarct volume and histopathological damage in vivo, and increased the astrocytes viability in vitro. Moreover, the treatment of Z-GS inhibited the astrocytes activation and down-regulated the mRNA levels of pro-inflammatory cytokines. Furthermore, the activated TLR4-NF-κB signaling pathways induced by MCAO or OGD were significantly suppressed by Z-GS treatment, which was achieved via inhibiting the phosphorylation of JNK. Our results demonstrated that Z-GS exerted neuroprotective and anti-inflammatory properties through preventing activation of TLR4-mediated pathway in the activated astrocytes after ischemia injury. Therefore, Z-GS could be considered as a promising candidate for the treatment of ischemic stroke.

Total glucosides of paeony suppresses experimental autoimmune uveitis in association with inhibition of Th1 and Th2 cell function in mice

Total glucosides of paeony (TGP) are active components extracted from the roots of Paeonia lactiflora Pall. In this study, we investigated the role and mechanisms of TGP in experimental autoimmune uveitis (EAU) model of mice. The C57BL/6 mice were randomly divided into three groups: sham group, EAU-control group, and EAU-TGP group. Clinical score of images of the eye fundus were taken on 7, 14, 21, and 28 days after induction of EAU. The concentrations of proinflammatory cytokines in intraocular fluid were measured at 14 days after EAU induction with the use of a multiplex assay system. Flow cytometry was used to analyze the frequency of CD4+, CD8+, interferon-gamma (IFN-γ), and CD4+/CD8+ ratio in spleen and lymph nodes. Western blotting was used to measure expressions of mitogen-activated protein kinase (MAPK) pathway-related proteins in retina. Clinical scores for uveitis were lower in TGP-treated EAU mice than those without TGP treatment. Importantly, the concentrations of cytokines induced by T-helper 1 (Th1) and T-helper 2 (Th2) cells in intraocular fluid were reduced in EAU mice treated with TGP. Furthermore, the frequency of CD4+, IFN-γ, and CD4+/CD8+ ratio was decreased and the frequency of CD8+ was increased in spleen and lymph nodes of mice treated with TGP. The anti-inflammatory effects of TGP were mediated by inhibiting the MAPK signaling pathways. Our results showed that TGP suppressed uveitis in mice via the inhibition of Th1 and Th2 cell function. Thus, TGP may be a promising therapeutic strategy for uveitis, as well as other ocular inflammatory diseases.

Reduced MBD2 expression enhances airway inflammation in bronchial epithelium in COPD

Background

Chronic obstructive pulmonary disease (COPD) is a common inflammatory lung disease characterized by inflammatory cells activation and production of inflammatory mediators. Methyl-CpG-binding domain protein 2 (MBD2) plays an important role in diverse immunological disorders by regulating immune cell functions, such as differentiation and mediator secretion. However, the role of MBD2 in COPD remains unknown.

Methods

MBD2 protein expression in lung tissues of patients with COPD and cigarette smoke (CS)-exposed mice were evaluated by Western blot and immunohistochemistry. The role of MBD2 in cigarette smoke extract (CSE)-induction of inflammatory mediator expression in the human bronchial epithelial (HBE) cell line was assessed by silencing MBD2 expression in vitro. The involvement of signaling pathways in mediation of inflammation was tested with signaling inhibitors.

Results

Compared with controls, MBD2 expression was distinctly reduced in the bronchial epithelium of both patients with COPD and CS-exposed mice. Moreover, MBD2 expression was decreased in HBE after CSE stimulation in vitro. Moreover, MBD2 knockdown enhanced interleukin (IL)-6 and IL-8 expression in HBE in the presence and absence of CSE treatment by the ERK signaling pathway.

Conclusion

MBD2 protein expression was reduced in the airway epithelium of COPD. In HBE, this reduced expression was associated with increased levels of IL-6 and IL-8 mediated by the ERK pathway. These results suggest that MBD2 could contribute to chronic airway inflammation in COPD.

Relationship between serum vitamin D levels and inflammatory markers in acute stroke patients

Introduction

Low serum vitamin D levels are associated with the development of poststroke depression (PSD). Inflammatory markers play an important role in pathophysiology of PSD. The relationship between vitamin D levels and inflammatory markers has been discussed in nonstroke individuals. The purposes of this study were to explore the relationship between vitamin D levels and inflammatory markers in acute stroke patients and examine the effect of vitamin D and inflammatory markers on PSD.

Methods

A total of 152 acute stroke patients were recruited. Serum levels of 25-hydroxyvitamin D and inflammatory markers were measured by standardized laboratory methods. Depression symptoms were assessed with the 17-item Hamilton Depression Scale (HAMD-17). Patients with the HAMD-17 scores ≥7 were identified to have depression symptoms.

Results

Serum vitamin D levels were negatively correlated with serum levels of interleukin-6 and high-sensitivity C-reactive protein (hsCRP) (r = -.244, p = .002; r = -.231, p = .004). Multiple regression analysis showed that interleukin-6 and hsCRP levels were associated with vitamin D levels (B = -0.355, p = .003; B = -2.085, p = .006), whereas age, height, weight, leukocyte count, neutrophil ratio, and lymphocyte rate could be omitted without changing the results. In multivariate analyses, the serum levels of vitamin D and interleukin-6 were associated with the development of PSD after adjusted possible variables (OR = 0.976, 95% CI: 0.958-0.994, p = .009; OR = 1.029, 95% CI: 1.003-1.055, p = .027).

Conclusions

Serum vitamin D levels are inversely associated with the levels of interleukin-6 and hsCRP, suggesting a potential anti-inflammatory role for vitamin D in stroke individuals.

Deregulation of microRNA-155 and its transcription factor NF-kB by polychlorinated biphenyls during viral infections

Polychlorinated biphenyls (PCBs), and similar environmental contaminants, have been linked to virus outbreaks and increased viral induced mortality since the 1970s. Yet the mechanisms behind this increased susceptibility remain elusive. It has recently been illustrated that the innate immune viral detection system is tightly regulated by small non-coding RNAs, including microRNAs (miRNAs). For virus infections miRNA-155 expression is an important host response against infection, and deregulation of this miRNA is closely associated with adverse outcomes. Thus, we designed a targeted in vitro study using primary chicken fibroblasts, first exposed to a mixture of PCBs (Arochlor-1250) before being stimulated with a synthetic RNA virus (poly I:C), to determine if PCBs have the potential to deregulate miRNA-155. In this paper, we provide the first data for the deregulation of miRNA-155 when a host is exposed to a mixture of PCBs before a virus infection. Thus, we provide important evidence that PCBs can be involved in the deregulation of important miRNA pathways involved in the immune system; thereby demonstrating novel insights into the mechanism of PCB toxicity on the immune system.

Anti-inflammatory Effects of Sinomenium Acutum Extract On Endotoxin-induced Uveitis in Lewis Rats

PURPOSE

Recent studies have reported the anti-inflammatory effect of Sinomenium acutum. We investigated the anti-inflammatory effect of sinomenine on endotoxin-induced uveitis in a rat model.

METHODS

Endotoxin-induced uveitis was induced in rat by lipopolysaccharide (LPS) immunization. Sinomenine (50mg/kg and 100mg/kg) was administered at 30 minutes before, 6 hours and 12 hours after LPS immunization. Clinical and histological severity was evaluated. Protein concentration and levels of tumor necrosis factor (TNF)-α and prostaglandin (PG)-E2 in aqueous humor were measured. Expression of activated Nuclear factor (NF)-κB p65 in ciliary body was also observed.

RESULTS

Clinical and histological severities were significantly milder in sinomenine-treated rat than in controls (P < 0.001). Sinomenine suppressed protein leakage and down-regulated the production of TNF-α and PG-E2 in a dose-dependent manner. Sinomenine treatment suppressed the translocation of the NF-κB p65 subunit into the nuclei.

CONCLUSION

Systemic administration of sinomenine suppressed the inflammation of ocular tissues. These findings suggest that sinomenine could be a novel therapeutic agent for the control of endogenous ocular inflammatory disease.

Central role of myeloid MCPIP1 in protecting against LPS-induced inflammation and lung injury

Although systemic inflammatory responses attributable to infection may lead to significant lung injury, the precise molecular mechanisms leading to lung damage are poorly understood and therapeutic options remain limited. Here, we show that myeloid monocyte chemotactic protein-inducible protein 1 (MCPIP1) plays a central role in protecting against LPS-induced inflammation and lung injury. Myeloid-specific MCPIP1 knockout mice developed spontaneous inflammatory syndromes, but at a late age compared to global MCPIP1 knockout mice. Moreover, mice with a myeloid-specific deletion of MCPIP1 were extremely sensitive to LPS-induced lung injury due to overproduction of proinflammatory cytokines and chemokines. We identified C/EBPβ and C/EBPδ, two critical transcriptional factors that drive cytokine production and lung injury, as targets of MCPIP1 RNase. LPS administration caused MCPIP1 protein degradation in the lungs. Pharmacological inhibition of MALT1, a paracaspase that cleaves MCPIP1, by MI-2 selectively increased the MCPIP1 protein levels in macrophages and in the lungs. Meanwhile, administration of MI-2 protected mice from LPS-induced inflammation, lung injury and death. Collectively, these results indicate that myeloid MCPIP1 is central in controlling LPS-induced inflammation and lung injury. Pharmacological inhibition of MALT1 protease activity may be a good strategy to treat inflammatory diseases by enhancing MCPIP1 expression in myeloid cells.

Interplay between miR-574-3p and hnRNP L regulates VEGFA mRNA translation and tumorigenesis

MicroRNAs (miRNAs) and heterogeneous nuclear ribonucleoproteins (hnRNPs) are families of sequence-specific, posttranscriptional modulators of gene expression. Despite extensive mechanistic and functional studies on both regulatory classes, the interactions and crosstalk between them are largely unexplored. We have reported that competition between miR-297 and hnRNP L to bind a 3΄UTR-localized CA-rich element (CARE) of VEGFA mRNA regulates its translation. Here, we show that translation of VEGFA mRNA in human myeloid cells is dictated by a bi-directional interaction between miR-574-3p, a CA-rich microRNA, and hnRNP L. In normoxia, miR-574-3p, acting as a decoy, binds cytoplasmic hnRNP L and prevents its binding to the CARE and stimulation of VEGFA mRNA translation, simultaneously permitting miR-297-mediated translational silencing. However, in hypoxia, cytoplasmic accumulation of Tyr³⁵⁹-phosphorylated hnRNP L sequesters miR-574-3p, overcoming its decoy activity and seed sequence-dependent gene silencing activity. Ectopically expressed miR-574-3p binds multiple RNA recognition motif (RRM) domains of hnRNP L, synergizes with miR-297, reduces VEGFA mRNA translation, and triggers apoptosis, thereby suppressing tumorigenesis. Our studies establish a novel condition-dependent interplay between a miRNA and an hnRNP that regulates their functions in a bidirectional manner.

Inflammatory Diseases and Growth: Effects on the GH-IGF Axis and on Growth Plate

This review briefly describes the most common chronic inflammatory diseases in childhood, such as cystic fibrosis (CF), inflammatory bowel diseases (IBDs), juvenile idiopathic arthritis (JIA), and intrauterine growth restriction (IUGR) that can be considered, as such, for the changes reported in the placenta and cord blood of these subjects. Changes in growth hormone (GH) secretion, GH resistance, and changes in the insulin-like growth factor (IGF) system are described mainly in relationship with the increase in nuclear factor-κB (NF-κB) and pro-inflammatory cytokines. Changes in the growth plate are also reported as well as a potential role for microRNAs (miRNAs) and thus epigenetic changes in chronic inflammation. Many mechanisms leading to growth failure are currently known; however, it is clear that further research in the field is still warranted.

Cytokine profile of NALT during acute stress and its possible effect on IgA secretion

Stress stimuli affect the immune system responses that occur at mucosal membranes, particularly IgA secretion. It has been suggested that acute stress increases the levels of IgA and that sympathetic innervation plays an important role in this process. We herein explore in a murine model how acute stress affects the Th1/Th2/Treg cytokine balance in NALT, and the possible role of glucocorticoids in this effect. Nine-week-old male CD1 mice were divided into three groups: unstressed (control), stressed (subjected to 4h of immobilization), and stressed after pretreatment with a single dose of the corticosterone receptor antagonist RU-486. The parameters evaluated included plasma corticosterone and epinephrine, IgA levels in nasal fluid (by ELISA), the percentage of CD19⁺B220⁺IgA⁺ lymphocytes and CD138⁺IgA⁺ plasma cells, and the mRNA expression of heavy α chain, J chain and pIgR. Moreover, the gene and protein expression of Th1 cytokines (TNFα, IL-2 and INF-γ), Th2 cytokines (IL-4 and IL-5) and Treg cytokines (IL-10 and TGFβ) were determined in nasal mucosa. The results show that acute stress generated a shift towards the dominance of an anti-inflammatory immune response (Th2 and Treg cytokines), evidenced by a significant rise in the amount of T cells that produce IL4, IL-5 and IL-10. This immune environment may favor IgA biosynthesis by CD138⁺IgA⁺ plasma cells, a process mediated mostly by glucocorticoids.

Withanolides against TLR4-Activated Innate Inflammatory Signalling Pathways: A Comparative Computational and Experimental Study

Innate inflammations are dominant causes of poor health and high mortality. The pathogen-associated molecular pattern and lipopolysaccharide (LPS) are sensed by immune cells through activation of toll-like receptor 4 leading to mitogen-activated protein kinases (MAPKs) and NF-κB activations. Controlled MAPK and Nf-κB inhibitors have been proposed as potential antiinflammatory drugs. Withania somnifera is an important medicinal herb with known antiinflammatory activity. In this study, the selected Withania somnifera extracts and withanolides were analysed on LPS-induced macrophages comparatively. Molecular docking analysis revealed withaferin A, withanone and withanolide A as effective withanolides against inflammatory target molecules. In experiments, withaferin A and withanone treatment had prominent suppressions on LPS-induced expression of pro-inflammatory cytokines in bone marrow-derived macrophages. Withaferin A regulated all the major four pathways (MAPKs and NF-κB) involved in innate inflammations. Similarly among the Withania extracts analysed, the in vitro propagated leaf and field grown root extracts containing high withaferin A content suppressed the inflammatory molecules through NF-κB and MAPK pathways. Withaferin A was found to be best in suppressing the activated inflammatory pathways among all the analysed withanolides. Therefore, withaferin A and extracts with high withaferin A content can be used as promising drug candidates against innate inflammations. Copyright © 2016 John Wiley & Sons, Ltd.

Monosodium urate crystal-induced pro-interleukin-1β production is post-transcriptionally regulated via the p38 signaling pathway in human monocytes

IL-1β is a key mediator of sterile inflammation in response to endogenous particulates, a type of damage-associated molecular pattern (DAMPs) molecule derived from damaged cells. Despite the well-known role of sterile particulates such as monosodium urate (MSU) crystals as inflammasome inducers in monocytes/macrophages, little is known regarding how pro-IL-1β synthesis is induced under sterile inflammatory conditions. We provide evidence that MSU crystals post-transcriptionally induce the rapid production of pro-IL-1β in human primary monocytes. Metabolic labeling and pull-down assays for newly-synthesized proteins clearly showed that MSU crystals rapidly, within 30 min, induce the synthesis of pro-IL-1β as well as global proteins. Notably, MSU crystal-induced pro-IL-1β synthesis is selectively dependent on the p38 MAPK pathway, whereas global protein synthesis is mediated via the mTOR, ERK1/2, and p38 pathways. Furthermore, inhibition of Mnk1, a substrate of p38, blocked MSU crystal-induced pro-IL-1β synthesis downstream of eIF4E phosphorylation. In addition, the p38 MAPK pathway leading to phosphorylation of MK2 was also critical for stabilization of pro-IL-1β mRNA following MSU stimulation. Our findings demonstrate that post-transcriptional regulation via p38 MAPK plays a central role in the rapid synthesis of pro-IL-1β in response to MSU crystals, which is an essential step for IL-1β production in human monocytes.

AAV8-Mediated Angiotensin-Converting Enzyme 2 Gene Delivery Prevents Experimental Autoimmune Uveitis by Regulating MAPK, NF-κB and STAT3 Pathways

Renin angiotensin system (RAS) is a key hormonal system which regulates the cardiovascular function and is implicated in several autoimmune diseases. With the discovery of the angiotensin-converting enzyme 2 (ACE2), a protective axis of RAS namely ACE2/Ang-(1-7)/Mas that counteracts the deleterious ACE/AngII/AT1R axis has been established. This axis is emerging as a novel target to attenuate ocular inflammation. However, the underlying molecular mechanisms remain unclear. We investigated the hypothesis that enhancing the activity of the protective axis of RAS by subretinal delivery of an AAV8 (Y733F)-ACE2 vector would protect against the ocular inflammation in experimental autoimmune uveitis (EAU) mice through regulating the local immune responses. Our studies demonstrated that increased ACE2 expression exerts protective effects on inflammation in EAU mouse by modulating ocular immune responses, including the differentiation of Th1/Th17 cells and the polarization of M1/M2 macrophages; whereas the systemic immune responses appeared not affected. These effects were mediated by activating the Ang-(1-7)/Mas and inhibiting the MAPK, NF-κB and STAT3 signaling pathways. This proof-of-concept study suggests that activation of ocular ACE2/Ang-(1-7)/Mas axis with AAV gene transfer modulates local immune responses and may be a promising, long-lasting therapeutic strategy for refractory and recurrent uveitis, as well as other inflammatory eye diseases.

Effects and mechanisms of Shaofu-Zhuyu decoction and its major bioactive component for Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) is used under the guidance of the theory of traditional Chinese medical sciences in clinical application. The Chinese herbal formula, Shaofu Zhuyu decoction (SFZYD), is considered as an effective prescription for treating Cold - Stagnation and Blood - Stasis (CSBS) primary dysmenorrhea. The previous studies showed the SFZYD exhibited significant anti-inflammation and analgesic effect. In this present study the metabolomics of CSBS primary dysmenorrhea diseased rats and the cytokine transcription in PHA stimulated-PBMC were investigated to explore the effects and mechanisms.

AIM OF THE STUDY

Explore a valuable insight into the effects and mechanisms of SFZYD on Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats.

MATERIALS AND METHODS

We established CSBS primary dysmenorrhea diseased rats according the clinical symptoms. A targeted tandem mass spectrometry (MS/MS)-based metabolomic platform was used to evaluate the metabolic profiling changes and the intervention effects by SFZYD. The PBMC cell was adopted to explore the mechanisms by analyzing the signaling pathway evaluated by expression of inflammatory cytokines, c-jun and c-fos and corresponding phosphorylation levels.

RESULTS

Estradiol, oxytocin, progesterone, endothelin, β-endorphin and PGF2α were restored back to the normal level after the treatment of SFZYD. Total twenty-five metabolites (10 in plasma and 15 in urine), up-regulated or down-regulated, were identified. These identified biomarkers underpinning the metabolic pathway including pentose and glucuronate interconversions, steroid hormone biosynthesis, and glycerophospholipid metabolism are disturbed in model rats. Among these metabolites, twenty one potential biomarkers were regulated after SFZYD treated. The compound of paeoniflorin, a major bioactive compound in SFZYD, was proved to regulate the MAPK signaling pathway by inhibiting the expression of IL-1β, IL-2, IL-10, IL-12, TNFα, INFγ, c-jun and c-fos in PHA stimulated-PBMC.

CONCLUSION

These findings indicated that SFZYD improved the metabolic profiling and biochemical indicators on CSBS primary dysmenorrhea rats. And the mechanisms were closely related with the regulation of the MAPK pathway by reduction in phosphorylated forms of the three MAPK (ERK1/2, p38 and JNK) and down regulation of c-jun and c-fos by paeoniflorin. The data could be provided the guidance for further research and new drug discovery.

Glutamine up-regulates MAPK phosphatase-1 induction via activation of Ca2+→ ERK cascade pathway

The non-essential amino acid L-glutamine (Gln) displays potent anti-inflammatory activity by deactivating p38 mitogen activating protein kinase and cytosolic phospholipase A₂ via induction of MAPK phosphatase-1 (MKP-1) in an extracellular signal-regulated kinase (ERK)-dependent way. In this study, the mechanism of Gln-mediated ERK-dependency in MKP-1 induction was investigated. Gln increased ERK phosphorylation and activity, and phosphorylations of Ras, c-Raf, and MEK, located in the upstream pathway of ERK, in response to lipopolysaccharidein vitro and in vivo. Gln-induced dose-dependent transient increases in intracellular calcium ([Ca²⁺]_i) in MHS macrophage cells. Ionomycin increased [Ca²⁺]_i and activation of Ras → ERK pathway, and MKP-1 induction, in the presence, but not in the absence, of LPS. The Gln-induced pathways involving Ca²⁺→ MKP-1 induction were abrogated by a calcium blocker. Besides Gln, other amino acids including L-phenylalanine and l-cysteine (Cys) also induced Ca²⁺ response, activation of Ras → ERK, and MKP-1 induction, albeit to a lesser degree. Gln and Cys were comparable in suppression against 2, 4-dinitrofluorobenzene-induced contact dermatitis. Gln-mediated, but not Cys-mediated, suppression was abolished by MKP-1 small interfering RNA. These data indicate that Gln induces MKP-1 by activating Ca²⁺→ ERK pathway, which plays a key role in suppression of inflammatory reactions.

Anti-inflammatory sesquiterpenes from Costus speciosus rhizomes

ETHNOPHARMACOLOGICAL RELEVANCE

Costus speciosus (Koen ex. Retz.) Sm. (crepe ginger, family Costaceae) is an ornamental plant used in traditional medicine for the treatment of inflammation, rheumatism, bronchitis, fever, headache, asthma, flatulence, constipation, helminthiasis, leprosy, skin diseases, hiccough, anemia, as well as burning sensation on urination.

AIM OF THE STUDY

The present study is designed to isolate and identify the active compounds from C. speciosus rhizomes and measure their anti-inflammatory activities.

MATERIALS AND METHODS

The n-hexane-CHCl3 soluble fraction of the MeOH extract of C. speciosus rhizomes has been subjected to a repeated column chromatography, including normal silica gel and RP-18 column to give eight compounds. The structures of these compounds were established by UV, IR, 1D ((1)H and (13)C), and 2D ((1)H-(1)H COSY, NOESY, HSQC, and HMBC) NMR experiments and HRESIMS data. In addition, the anti-inflammatory activity of compounds 1-8 was evaluated by measuring the levels IL-6, IL-1β, TNF-α, COX-2, lipoxgenase-5, and PGE2 using enzyme-linked immunosorbent assay.

RESULTS

The n-hexane-CHCl3 soluble fraction afforded a new eudesmane acid, specioic acid (8), along with seven known compounds, 22,23-dihydrospinasterone (1), dehydrodihydrocostus lactone (mokko lactone) (2), dehydrocostus lactone (3), stigmasterol (4), arbusculin A (5), santamarine (douglanin) (6), and reynosin (7). Compounds 1, 4, and 5-7 were isolated for the first time C. speciosus. Compounds 1-4 displayed potent anti-inflammatory activity, while 7 and 8 showed moderate activity. Compounds 1-8 exhibited a concentration-related decrease in the levels of IL-1β, IL-6, TNF-α, PGE2, lipoxgenase-5, and COX-2. Compounds 5 and 6 did not significantly decrease levels of different cytokines, PGE2, lipoxgenase-5, and COX-2 from PHA treatment at 1 µM. However, all tested compounds significantly decreased cytokines, PGE2, lipoxgenase-5, and COX-2 levels at concentration 100 µM. It is noteworthy that compounds 1-4 had the highest activity, where it lowered levels of cytokines, PGE2, lipoxgenase-5, and COX-2 to the extent that was no statistical difference from the control group. Thus, they decreased proinflammatory cytokines (IL-1β, IL-6, and TNF-α) with decreased level of the target enzymes (COX-2 and lipoxgenase-5) and subsequent reduction of its inflammatory product (PGE2).

CONCLUSION

Good anti-inflammatory activities exhibited of the isolated compounds from C. speciosus corroborate the usefulness of this plant in the traditional treatment of inflammation and related symptoms.

Inflammation Modulates RLIP76/RALBP1 Electrophile-Glutathione Conjugate Transporter and Housekeeping Genes in Human Blood-Brain Barrier Endothelial Cells

Endothelial cells are often present at inflammation sites. This is the case of endothelial cells of the blood-brain barrier (BBB) of patients afflicted with neurodegenerative disorders such as Alzheimer's, Parkinson's, or multiple sclerosis, as well as in cases of bacterial meningitis, trauma, or tumor-associated ischemia. Inflammation is a known modulator of gene expression through the activation of transcription factors, mostly NF-κB. RLIP76 (a.k.a. RALBP1), an ATP-dependent transporter of electrophile-glutathione conjugates, modulates BBB permeability through the regulation of tight junction function, cell adhesion, and exocytosis. Genes and pathways regulated by RLIP76 are transcriptional targets of tumor necrosis factor alpha (TNF-α) pro-inflammatory molecule, suggesting that RLIP76 may also be an inflammation target. To assess the effects of TNF-α on RLIP76, we faced the problem of choosing reference genes impervious to TNF-α. Since such genes were not known in human BBB endothelial cells, we subjected these to TNF-α, and measured by quantitative RT-PCR the expression of housekeeping genes commonly used as reference genes. We find most to be modulated, and analysis of several inflammation datasets as well as a metaanalysis of more than 5000 human tissue samples encompassing more than 300 cell types and diseases show that no single housekeeping gene may be used as a reference gene. Using three different algorithms, however, we uncovered a reference geneset impervious to TNF-α, and show for the first time that RLIP76 expression is induced by TNF-α and follows the induction kinetics of inflammation markers, suggesting that inflammation can influence RLIP76 expression at the BBB. We also show that MRP1 (a.k.a. ABCC1), another electrophile-glutathione transporter, is not modulated in the same cells and conditions, indicating that RLIP76 regulation by TNF-α is not a general property of glutathione transporters. The reference geneset uncovered herein should aid in future gene expression studies in inflammatory conditions of the BBB.

Tristetraprolin mediates anti-inflammatory effects of carbon monoxide on lipopolysaccharide-induced acute lung injury

Low-dose inhaled carbon monoxide is reported to suppress inflammatory responses and exhibit a therapeutic effect in models of lipopolysaccharide (LPS)-induced acute lung injury (ALI). However, the precise mechanism by which carbon monoxide confers protection against ALI is not clear. Tristetraprolin (TTP; official name ZFP36) exerts anti-inflammatory effects by enhancing decay of proinflammatory cytokine mRNAs. With the use of TTP knockout mice, we demonstrate here that the protection by carbon monoxide against LPS-induced ALI is mediated by TTP. Inhalation of carbon monoxide substantially increased the pulmonary expression of TTP. carbon monoxide markedly enhanced the decay of mRNA-encoding inflammatory cytokines, blocked the expression of inflammatory cytokines, and decreased tissue damage in LPS-treated lung tissue. Moreover, knockout of TTP abrogated the anti-inflammatory and tissue-protective effects of carbon monoxide in LPS-induced ALI. These results suggest that carbon monoxide-induced TTP mediates the protective effect of carbon monoxide against LPS-induced ALI by enhancing the decay of mRNA encoding proinflammatory cytokines.

Analysis of immune cell populations and cytokine profiles in murine splenocytes exposed to whole-body low-dose irradiation

PURPOSE

In contrast to high-dose therapeutic irradiation, definitive research detailing the physiological effects of low-dose irradiation is limited. Notably, the immunological response elicited after low-dose irradiation remains controversial.

MATERIALS AND METHODS

Female C57BL/6 mice were whole- body-irradiated with a single or three daily fractions up to a total dose of 0.1, 1, or 10 cGy. Blood and spleen were harvested 2, 7 and 14 days after irradiation.

RESULTS

The splenic CD4(+) T cell subpopulations were temporarily increased at 2 days after single or fractionated irradiation, whereas the percentage of dendritic cells (DC) and macrophages was decreased. Whereas CD8(+) T cell populations were decreased in single-dose irradiated mice at day 7, early and sustained reduction of CD8(+) T cell numbers was observed in fractionated- dose-irradiated mice from day 2 until day 14. In addition, single-dose irradiation resulted in a Th1 cytokine expression profile, whereas fractionated-dose irradiation drove a Th2 shift. Additionally, increased expression of immune-related factors was observed at early time-points with single-dose irradiation, in contrast to the dose-independent induction following fractionated-dose irradiation.

CONCLUSIONS

Our results demonstrate that low-dose irradiation modulates the immune response in mice, where the sensitivity and kinetics of the induced response vary according to the dosing method.

Functional regulation of Zfp36l1 and Zfp36l2 in response to lipopolysaccharide in mouse RAW264.7 macrophages

Background

The tristetraprolin (TTP) family of mRNA-binding proteins contains three major members, Ttp, Zfp36l1, and Zfp36l2. Ttp down-regulates the stability of AU-rich element–containing mRNAs and functions as an anti-inflammation regulator.

Methods

To examine whether other TTP family proteins also play roles in the inflammatory response, their expression profiles and the possible mRNA targets were determined in the knockdown cells.

Results

Ttp mRNA and protein were highly induced by lipopolysaccharide (LPS), whereas Zfp36l1 and Zfp36l2 mRNAs were down-regulated and their proteins were phosphorylated during early lipopolysaccharide stimulation. Biochemical and functional analyses exhibited that the decrease of Zfp36l2 mRNA was cross-regulated by Ttp. Knockdown of Zfp36l1 and Zfp36l2 increased the basal level of Mkp-1 mRNAs by prolonging its half-life. Increasing the expression of Mkp-1 inhibited the activation of p38 MAPK under lipopolysaccharide stimulation and down-regulated Tnfα, and Ttp mRNA. In addition, hyper-phosphorylation of Zfp36l1 might stabilize Mkp-1 expression by forming a complex with the adapter protein 14-3-3 and decreasing the interaction with deadenylase Caf1a.

Conclusions

Our findings imply that the expression and phosphorylation of Zfp36l1 and Zfp36l2 may modulate the basal level of Mkp-1 mRNA to control p38 MAPK activity during lipopolysaccharide stimulation, which would affect the inflammatory mediators production. Zfp36l1 and Zfp36l2 are important regulators of the innate immune response.

Electronic supplementary material

The online version of this article (doi:10.1186/s12950-015-0088-x) contains supplementary material, which is available to authorized users.

Mechanism of glutamine inhibition of cytosolic phospholipase a2 (cPLA2 ): Evidence of physical interaction between glutamine-Induced mitogen-activated protein kinase phosphatase-1 and cPLA2

Non-essential amino acid L-glutamine (Gln) possesses anti-inflammatory activity via deactivating cytosolic phospholipase A2 (cPLA2 ). We showed previously that Gln deactivated cPLA2 indirectly via dephosphorylating p38 mitogen-activated protein kinase (MAPK), the major kinase for cPLA2 phosphorylation, through inducing MAPK phosphatase-1 (MKP-1). In this study, we investigated the precise mechanism underlying Gln deactivation of cPLA2 . In lipopolysaccharide (LPS)-treated mice, Gln injection resulted in dephosphorylation of phosphorylated cPLA2 (p-cPLA2 ), which coincided with rapid Gln induction of MKP-1. MKP-1 small interfering RNA (siRNA) abrogated the ability of Gln to induce MKP-1 as well as the dephosphorylation of cPLA2 . Co-immunoprecipitation and in-situ proximity ligation assay revealed a physical interaction between MKP-1 and p-cPLA2 . In a murine model of allergic asthma, we also demonstrated the physical interaction between MKP-1 and p-cPLA2 . Furthermore, Gln suppressed various allergic asthma phenotypes, such as neutrophil and eosinophil recruitments into the airway, airway levels of T helper type 2 (Th2) cytokines [interleukin (IL)-4, IL-5 and IL-13], airway hyperresponsiveness, mucin production and metabolites (leukotriene B4 and platelet-activating factor) through inhibiting cPLA2 in a MKP-1-dependent manner. These data suggest that MKP-1 uses cPLA2 , in addition to p38, as a substrate, which further potentiates the anti-inflammatory action of Gln.

Coordinated post-transcriptional regulation of the chemokine system: messages from CCL2

The molecular cross-talk between epithelium and immune cells in the airway mucosa is a key regulator of homeostatic immune surveillance and is crucially involved in the development of chronic lung inflammatory diseases. The patterns of gene expression that follow the sensitization process occurring in allergic asthma and chronic rhinosinusitis and those present in the neutrophilic response of other chronic inflammatory lung diseases such as chronic obstructive pulmonary disease (COPD) are tightly regulated in their specificity. Studies exploring the global transcript profiles associated with determinants of post-transcriptional gene regulation (PTR) such as RNA-binding proteins (RBP) and microRNAs identified several of these factors as being crucially involved in controlling the expression of chemokines upon airway epithelial cell stimulation with cytokines prototypic of Th1- or Th2-driven responses. These studies also uncovered the participation of these pathways to glucocorticoids' inhibitory effect on the epithelial chemokine network. Unmasking the molecular mechanisms of chemokine PTR may likely uncover novel therapeutic strategies for the blockade of proinflammatory pathways that are pathogenetic for asthma, COPD, and other lung inflammatory diseases.

CNOT7/hCAF1 is involved in ICAM-1 and IL-8 regulation by tristetraprolin

Tristetraprolin (TTP) is an RNA-binding protein which can bind to the AU-rich elements (AREs) at the 3'-untranslated region (3'-UTR) of target mRNA and promote mRNA deadenylation and degradation. We have shown in a previous study that TTP regulates tumor necrosis factor-α (TNF-α)-induced expression of intercellular adhesion molecule-1 (ICAM-1) and interleukin-8 (IL-8), both of whose mRNAs have AREs in the 3'-UTR, in human pulmonary microvascular endothelial cells (HPMEC) through destabilizing target mRNAs, nevertheless, the mechanism by which TTP promotes mRNA decay remains unclear. Observations have indicated that TTP can interact with CAF1 (CNOT7/hCAF1 in human), a subunit of the CCR4-NOT complex with deadenylase activity. Another study illustrated that TTP can directly bind to CNOT1, the scaffold subunit of the CCR4-NOT complex. The present study showed that TTP bound to the AREs of ICAM-1 and IL-8 mRNAs and was coimmunoprecipitated with intracellular ICAM-1 and IL-8 mRNAs. TTP, CNOT7 and CNOT1 were coimmunoprecipitated in HPMEC. CNOT7 silencing stabilized ICAM-1 and IL-8 mRNAs and increased ICAM-1 and IL-8 production following TNF-α stimulation. These results, together with our previous study, suggest that CNOT7/hCAF1 is involved in ICAM-1 and IL-8 regulation by TTP in HPMEC.

Regulation of pancreatic inflammation by connective tissue growth factor (CTGF/CCN2)

Pancreatitis is caused by long-term heavy alcohol consumption, which results in injury and death of pancreatic acinar cells (PAC). The PAC play a pivotal role in mediating early inflammatory responses but the underlying mechanisms remain poorly understood. Treatment of C57BL/6 mice with ethanol and cerulein resulted in increased staining for acinar interleukin- 1b (IL-1b), chemokine (C-C motif) ligand 3 (CCL3), or connective tissue growth factor (CTGF/CCN2) by Day 16 and this was associated with increased infiltration of F4/80-positive macrophages and increased expression of pancreatic CTGF/CCN2 mRNA. Compared with wild-type Swiss Webster mice, ethanol treatment of pan-green fluorescent protein (GFP)-CTGF/CCN2 transgenic mice caused enhanced acinar staining for GFP or CTGF/CCN2 and a significant increase in pancreatic infiltration of F4/80-positive macrophages or NIMP-R14-positive neutrophils. Treatment of primary mouse PAC or the rat AR42J PAC line with ethanol or CTGF/CCN2 resulted in enhanced expression of IL-1b or CCL3. Conditioned medium from CTGF/CCN2-treated AR42J cells induced chemotaxis in NR8383 macrophages and this response was abrogated in a dose dependent manner by addition of BX471, an inhibitor of chemokine (C-C motif) receptor 1. These results reveal that acinar CTGF/CCN2 plays a novel role in alcohol-induced inflammatory processes in the pancreas by increasing infiltration of macrophages and neutrophils and increasing acinar production of inflammatory mediators such as IL-1b or CCL3. The early production of CTGF/CCN2 by PAC to drive inflammation is distinct from its previously reported production by pancreatic stellate cells to drive fibrosis at later stages of pancreatic injury.

Low-dose γ-radiation inhibits IL-1β-induced dedifferentiation and inflammation of articular chondrocytes via blockage of catenin signaling

Although low-dose radiation (LDR) regulates a wide range of biological processes, limited information is available on the effects of LDR on the chondrocyte phenotype. Here, we found that LDR, at doses of 0.5–2 centiGray (cGy), inhibited interleukin (IL)-1β-induced chondrocyte destruction without causing side effects, such as cell death and senescence. IL-1β treatment induced an increase in the expression of α-, β-, and γ-catenin proteins in chondrocytes via Akt signaling, thereby promoting dedifferentiation through catenin-dependent suppression of Sox-9 transcription factor expression and induction of inflammation through activation of the NF-κB pathway. Notably, LDR blocked cartilage disorders by inhibiting IL-1β-induced catenin signaling and subsequent catenin-dependent suppression of the Sox-9 pathway and activation of the NF-κB pathway, without directly altering catenin expression. LDR also inhibited chondrocyte destruction through the catenin pathway induced by epidermal growth factor, phorbol 12-myristate 13-acetate, and retinoic acid. Collectively, these results identify the molecular mechanisms by which LDR suppresses pathophysiological processes and establish LDR as a potentially valuable therapeutic tool for patients with cytokine- or soluble factors-mediated cartilage disorders.

Soluble calreticulin induces tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 production by macrophages through mitogen-activated protein kinase (MAPK) and NFκB signaling pathways

We have recently reported that soluble calreticulin (CRT) accumulates in the sera of patients with rheumatoid arthritis or systemic lupus erythematosus. Moreover, following self-oligomerization, soluble recombinant CRT (rCRT) polypeptides exhibit potent immunostimulatory activities including macrophage activation in vitro and antibody induction in vivo. This study was designed to further investigate the underlying molecular mechanisms for soluble CRT-induced macrophage activation. Treatment of murine macrophages with oligomerized rCRT (OrCRT) led to (i) TNF-α and IL-6 transcription and protein expression without affecting intracellular mRNA stability; and (ii) IκBα degradation, NFκB phosphorylation and sustained MAPK phosphorylation in cells. Inhibition of IKK and JNK in macrophages substantially abrogated production of TNF-α and IL-6 induced by OrCRT, while ERK suppression only reduced IL-6 expression in parallel experiments. In vitro, fucoidan, a scavenger receptor A (SRA)-specific ligand, significantly reduced the uptake of FITC-labeled OrCRT by macrophages and subsequent MAPK and NFκB activation, thereby suggesting SRA as one of the potential cell surface receptors for soluble CRT. Together, these data indicate that soluble CRT in oligomerized form could play a pathogenic role in autoimmune diseases through induction of pro-inflammatory cytokines (e.g., TNF-α and IL-6) by macrophages via MAPK-NFκB signaling pathway.

A functional link between heme oxygenase-1 and tristetraprolin in the anti-inflammatory effects of nicotine

Nicotine stimulates the cholinergic anti-inflammatory pathway and prevents excessive inflammation by inhibiting the release of inflammatory cytokines from macrophages. We have previously reported that heme oxygenase-1 (HO-1) and tristetraprolin (TTP) are induced by nicotine and mediate the anti-inflammatory function of nicotine in macrophages. However, it was not clear whether the two molecules are functionally linked. In this study, we sought to determine whether HO-1 associates with TTP to mediate the anti-inflammatory effects of nicotine. Inhibition of HO-1 activity or HO-1 expression attenuated the effects of nicotine on STAT3 activation, TTP induction, and TNF-α production in LPS-treated macrophages. Induction of HO-1 expression increased the level of TTP in the absence of nicotine. In an LPS-induced endotoxemia model, HO-1 deficiency blocked the effects of nicotine on the STAT3 phosphorylation, TTP induction, and LPS-induced TNF-α production in the liver. Downregulation of STAT3 by siRNA attenuated the effect of nicotine on TTP expression and TNF-α production but did not affect the nicotine-mediated induction of HO-1. In TTP knockout mice, nicotine treatment enhanced HO-1 expression and STAT3 activation but failed to inhibit LPS-induced TNF-α production. Our results suggest that HO-1 and TTP are functionally linked in mediating the anti-inflammatory effects of nicotine; HO-1 is necessary for the induction of TTP by nicotine. This novel nicotine-HO-1-TTP signaling pathway provides new possibilities for the treatment of inflammatory diseases.

Two novel homologs of high mobility group box 3 gene in grass carp (Ctenopharyngodon idella): potential roles in innate immune responses

High mobility group box 3 (HMGB3) protein is a universal sentinel in the activation of innate antiviral immune responses in mammalian cells of limited tissues. However, the underlying immune functions of HMGB3 responding to viruses and viral/bacterial pathogen-associated molecular patterns (PAMPs) are still unknown in teleosts. In the present study, two novel homologs of grass carp (Ctenopharyngodon idella) HMGB3 (designated as CiHMGB3a and CiHMGB3b) were identified and characterized. Quantitative RT-PCR analysis showed that CiHMGB3a and CiHMGB3b were widely expressed in tissues. The mRNA expressions of CiHMGB3a and CiHMGB3b were induced by grass carp reovirus (GCRV) challenges both in tissues and in cells, and CiHMGB3a played a more active role in antiviral immune responses. Viral PAMP stimulation evidenced that CiHMGB3a and CiHMGB3b mediated immune responses in CIK (C. idella kidney) cells. Interestingly, CiHMGB3a had little impact on bacterial PAMPs (LPS and PGN), whereas CiHMGB3b was critical responding to bacterial PAMPs stimulation. In overexpressions of CiHMGB3a and CiHMGB3b cells, the transcriptional levels of CiHMGB3a, CiHMGB3b, CiTRIF, CiIPS-1, CiIFN-I and CiMx1 were remarkably induced. In addition, CiMyD88 had vital impact on antiviral signaling channels in overexpression of CiHMGB3b cells. Furthermore, 96-well plate staining assay, virus titer test and GCRV quantitative analysis collectively indicated CiHMGB3a and CiHMGB3b exhibited substantial antiviral activity. These results suggest that CiHMGB3a and CiHMGB3b exert important functions in antiviral immune responses by TLRs and RLRs signaling pathways. Taken together, current study provides the first evidence that HMGB3 participates in broad antiviral and antibacterial immune responses in teleosts.

Diminazene aceturate (Berenil) modulates LPS induced pro-inflammatory cytokine production by inhibiting phosphorylation of MAPKs and STAT proteins

Although diminazene aceturate (Berenil) is widely used as a trypanolytic agent in livestock, its mechanisms of action remain poorly understood. We previously showed that Berenil treatment suppresses pro-inflammatory cytokine production by splenic and liver macrophages leading to a concomitant reduction in serum cytokine levels in mice infected with Trypanosoma congolense or challenged with LPS. Here, we investigated the molecular mechanisms through which Berenil alters pro-inflammatory cytokine production by macrophages. We show that pre-treatment of macrophages with Berenil dramatically suppressed IL-6, IL-12 and TNF-α production following LPS, CpG and Poly I:C stimulation without altering the expression of TLRs. Instead, it significantly down-regulated phosphorylation of mitogen-activated protein kinases (p38, extracellular signal-regulated kinase and c-Jun N-terminal kinases), signal transducer and activator of transcription (STAT) proteins (STAT1 and STAT3) and NF-кB p65 activity both in vitro and in vivo. Interestingly, Berenil treatment up-regulated the phosphorylation of STAT5 and the expression of suppressor of cytokine signaling 1 (SOCS1) and SOCS3, which are negative regulators of innate immune responses, including MAPKs and STATs. Collectively, these results show that Berenil down-regulates macrophage pro-inflammatory cytokine production by inhibiting key signaling pathways associated with cytokine production and suggest that this drug may be used to treat conditions caused by excessive production of inflammatory cytokines.

DUSP1 Gene Polymorphisms Are Associated with Obesity-Related Metabolic Complications among Severely Obese Patients and Impact on Gene Methylation and Expression

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.