Oral administration of 3,3'-diselenodipropionic acid prevents thoracic radiation induced pneumonitis in mice by suppressing NF-kB/IL-17/G-CSF/neutrophil axis

The incidence of symptomatic radiation induced lung pneumonitis (RILP), a major dose limiting side effect of thoracic radiotherapy, is in the range of 15-40%. Therapeutic options for the prevention and treatment of RILP are limited. Hence there is a need for developing novel radioprotectors to prevent RILP which can be patient compliant. This study sought to evaluate the efficacy of oral 3,3'-diselenodipropionic acid (DSePA), a novel selenocystine derivative to prevent RILP. C3H/HeJ (pneumonitis responding) mice received a single dose of 18 Gy, whole thorax irradiation and a subset were treated with DSePA orally (2.5 mg/kg), three times per week beginning 2 h post irradiation and continued till 6 months. DSePA delayed onset of grade ≥ 2 RILP by 45 days compared to radiation control (~105 versus ~60 days). It also reversed the severity of pneumonitis in 3/10 radiation treated mice leading to significant improvement in asymptomatic survival compared to radiation control (~180 versus ~102 days). DSePA significantly (p < 0.05) reduced the radiation-mediated infiltration of polymorphonuclear neutrophils (PMN) and elevation in levels of cytokines such as IL1-β, ICAM-1, E-selectin, IL-17 and TGF-β in the bronchoalveolar lavage fluid. Moreover DSePA lowered PMN-induced oxidants, maintained glutathione peroxidase activity and suppressed NF-kB/IL-17/G-CSF/neutrophil axis in the lung of irradiated mice. Additionally, this compound did not protect A549 (lung cancer) derived xenograft tumor from radiation exposure in SCID mice. DSePA offers protection to normal lung against RILP without affecting radiation sensitivity of tumors. It has the potential to be developed as an oral agent for preventing RILP.

Interleukin-8 and nuclear factor kappa B are increased and positively correlated in myelodysplastic syndrome

The pathogenesis of myelodysplastic syndromes (MDS) is complex and depends on the interaction between aberrant hematopoietic cells and their microenvironment, probably including aberrations in cytokines and their signaling pathways. To evaluate interleukin-8 (IL-8) plasma levels and nuclear factor kappa B (NF-kB) in patients with MDS and to test possible correlation between IL-8 and NF-Kb, a total of 45 individuals were analyzed: 25 consecutive adult de novo MDS patients and 20 sex and age-matched healthy elderly volunteers. IL-8 analysis was performed by ELISA and activity of NF-kB by chemiluminescent assay. MDS patients showed higher level of IL-8 when compared to controls (p = 0.006). Patients aged 75 and above showed even higher levels (p = 0.035). NF-kB activity was significantly elevated in MDS patients when compared to controls (p < 0.0001) and higher in patients older than 75 years (p = 0.047). NF-kB activity was associated with higher serum ferritin (p = 0.042) and higher percentage of blasts (p = 0.028). A significant positive correlation between IL-8 and NF-kB was demonstrated (r = 0.480; p = 0.015). Many pathways involved in pathophysiology of MDS have been recently described, suggesting that an inflammatory process may act as a pathogenic driver. In this study, significantly elevated levels of IL-8 and NF-kB were demonstrated in MDS patients, with positive association of NF-kB with some markers of poor prognosis. A positive correlation between IL-8 and NF-kB suggests they cooperate as part of a complex networking of immune and inflammatory factors involved in MDS.

Human amnion mesenchymal cells are pro-inflammatory when activated by the Toll-like receptor 2/6 ligand, macrophage-activating lipoprotein-2

INTRODUCTION

Infection accounts for over 40% of preterm premature rupture of the fetal membranes (PPROM), a major cause of preterm birth. Toll-like receptors (TLR) play key roles in pathogen surveillance but their expression and function in amnion mesenchymal cells (AMC) is unclear. The aims of this study were to determine the expression of all TLR isoforms and the effect of macrophage-activating lipoprotein-2 (MALP-2), derived from a common pathogen involved in PPROM, on human AMC.

METHODS

AMC were isolated from normal, term amnion from repeat cesarean section. Semi-quantitative RT-PCR, immunocytochemistry, immunohistochemistry and western blotting were used to detect TLR isoform expression. Immunocytochemistry of NF-κB p65, pro-inflammatory cytokine secretion (ELISA), MTT assay, LDH assay, immunoblotting of cytosolic cytochrome c and cleaved caspase-3, and expression of 84 microRNAs by Qiagen miRNA PCR array were used to determine the functional effect of MALP-2 on AMC.

RESULTS

TLR1-10 was detected in AMC, and protein expression of TLR2, 4, and 6 were confirmed. MALP-2 induced nuclear translocation of p65, reaching significance after 45 min (ANOVA, P < 0.05). MALP-2 did not cause apoptosis but did lead to significant secretion of IL-4, IL-6, and IL-8 (P < 0.05, 0.01, 0.001, respectively) and significant changes in miRNA-320a and miRNA-18a (P < 0.05).

DISCUSSION

These results suggest that AMC elicit a pro-inflammatory response following stimulation with the known TLR2/6 ligand MALP-2. This data supports the idea that AMC express the innate immune system receptors that could help with immune surveillance during infection and contribute to inflammatory responses that lead to PPROM.

Adrenomedullin mediates tumor necrosis factor-α-induced responses in dorsal root ganglia in rats

Adrenomedullin (AM), a member of the calcitonin gene-related peptide (CGRP) family, has been demonstrated to be a pain peptide. This study investigated the possible involvement of AM in tumor necrosis factor-alpha (TNF-α)-induced responses contributing to neuronal plasticity in the dorsal root ganglia (DRG). Exposure of the DRG explant cultures to TNF-α (5nM) for 48h upregulated the expression of AM mRNA. The treatment with TNF-α also increased the level of CGRP, CCL-2 and MMP-9 mRNA in the cultured DRG. This increase was attenuated by the co-treatment with the selective AM receptor antagonist AM22-52 (2μM). The blockade of AM receptors inhibited TNF-α-induced increase of the glial fibrillary acidic protein (GFAP), interleukin-1β (IL-1β), phosphorylated cAMP response element binding protein (pCREB) and nuclear factor kappa B (pNF-κB) proteins. On the other hand, the treatment with the AM receptor agonist AM1-50 (10nM) for 96h induced an increase in the level of GFAP, IL-1β, pCREB and pNF-κB proteins. The inhibition of AM activity did not change TNF-α-induced phosphorylation of extracellular signal-related kinase (pERK) while the treatment with AM1-50 still increased the level of pERK in the cultured DRG. Immunofluorescence assay showed the colocalization of AM-like immunoreactivity (IR) with TNF-α-IR in DRG neurons. The present study suggests that the increased AM receptor signaling mediated the many, but not all, TNF-α-induced activities, contributing to peripheral sensitization in neuropathic pain.