ATF3-mediated NRF2/HO-1 signaling regulates TLR4 innate immune responses in mouse liver ischemia/reperfusion injury

Activating transcription factor 3 (ATF3) is a stress-induced transcription factor that has been shown to repress inflammatory gene expression in multiple cell types and diseases. However, little is known about the roles and mechanisms of ATF3 in liver ischemia/reperfusion injury (IRI). In warm and cold liver IRI models, we showed that ATF3 deficiency significantly increased ischemia/reperfusion (IR)-stressed liver injury, as evidenced by increased serum alanine aminotransferase levels, histological liver damage, and hepatocellular apoptosis. These may correlate with inhibition of the intrahepatic nuclear factor erythroid-derived 2-related factor 2/heme oxygenase-1 (NRF2/HO-1) signaling pathway leading to enhancing Toll-like receptor 4/nuclear factor kappa beta (TLR4/NF-κB) activation, pro-inflammatory programs and macrophage/neutrophil trafficking, while simultaneously repressing anti-apoptotic molecules in ischemic liver. Interestingly, activation of NRF2/HO-1 signaling using an NRF2 activator, oltipraz (M2), during hepatic IRI-rescued ATF3 anti-inflammatory functions in ATF3-deficient mice. For in vitro studies, ATF3 ablation in lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages (BMMs) depressed levels of NRF2/HO-1 and PI3K/AKT, resulting in enhanced TLR4/NF-κB activation. Pretreatment of LPS-stimulated BMMs with M2 increased NRF2/HO-1 expression, promoted PI3K/AKT, which in turn suppressed TLR4/NF-κB-mediated proinflammatory mediators. Thus, our results first demonstrate ATF3-mediated NRF2/HO-1 signaling in the regulation of TLR4-driven inflammatory responses in IR-stressed livers. Our findings provide a rationale for a novel therapeutic strategy for managing IR-induced liver injury.

Using pet-ct to reduce futile thoracotomy rates in non-small-cell lung cancer: a population-based review

BACKGROUND

Combined positron-emission tomography and computed tomography (pet-ct) reduces futile thoracotomy (ft) rates in patients with non-small-cell lung cancer (nsclc). We sought to identify preoperative risk factors for ft in patients staged with pet-ct.

METHODS

We retrospectively reviewed all patients referred to the BC Cancer Agency during 2009-2010 who underwent pet-ct and thoracotomy for nsclc. Patients with clinical N2 disease were excluded. An ft was defined as any of a benign lesion; an exploratory thoracotomy; pathologic N2 or N3, stage iiib or iv, or inoperable T3 or T4 disease; and recurrence or death within 1 year of surgery.

RESULTS

Of the 108 patients who met the inclusion criteria, ft occurred in 27. The main reason for ft was recurrence within 1 year (14 patients) and pathologic N2 disease (10 patients). On multivariate analysis, an Eastern Cooperative Oncology Group performance status greater than 1, a pet-ct positive N1 status, a primary tumour larger than 3 cm, and a period of more than 16 weeks from pet-ct to surgery were associated with ft. N2 disease that had been negative on pet-ct occurred in 21% of patients with a pet-ct positive N1 status and in 20% of patients with tumours larger than 3 cm and non-biopsy mediastinal staging only. The combination of pet-ct positive N1 status and a primary larger than 3 cm had 85% specificity, and the presence of either risk factor had 100% sensitivity, for ft attributable to N2 disease.

CONCLUSIONS

To reduce ft attributable to N2 disease, tissue biopsy for mediastinal staging should be considered for patients with pet-ct positive N1 status and with tumours larger than 3 cm even with a pet-ct negative mediastinum.

Discontinuous properties of current-induced magnetic domain wall depinning

The current-induced motion of magnetic domain walls (DWs) confined to nanostructures is of great interest for fundamental studies as well as for technological applications in spintronic devices. Here, we present magnetic images showing the depinning properties of pulse-current-driven domain walls in well-shaped Permalloy nanowires obtained using photoemission electron microscopy combined with x-ray magnetic circular dichroism. In the vicinity of the threshold current density (J_th = 4.2 × 10¹¹ A.m⁻²) for the DW motion, discontinuous DW depinning and motion have been observed as a sequence of “Barkhausen jumps”. A one-dimensional analytical model with a piecewise parabolic pinning potential has been introduced to reproduce the DW hopping between two nearest neighbour sites, which reveals the dynamical nature of the current-driven DW motion in the depinning regime.

Concurrent erlotinib and radiotherapy for chemoradiotherapy-intolerant esophageal squamous cell carcinoma patients: results of a pilot study

Concurrent chemoradiotherapy is the standard treatment for patients with locally advanced esophageal squamous cell carcinoma. However, a number of patients present intolerance to chemoradiotherapy because of advanced age or malnutrition. Erlotinib, an inhibitor of epidermal growth factor receptor tyrosine kinase, was shown to be effective in treating esophageal carcinoma, with mild toxicities. In this pilot study, we investigated the safety and efficacy of concurrent erlotinib and radiotherapy as an alternative treatment modality for esophageal carcinoma patients who are intolerant to chemoradiotherapy. Pathologically diagnosed esophageal squamous cell carcinoma patients who could not tolerate concurrent chemoradiotherapy were enrolled. All patients were treated with concurrent erlotinib and intensity-modulated radiation therapy. Erlotinib was given orally for 60 days (150 mg per day). Radiotherapy (total dose, 60 Gy) was given at dosages of 2 Gy for a total of 30 times. Immunohistochemical staining was performed to assess epidermal growth factor receptor expression. Toxicities were evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events (version 3.0). The overall survival, progression-free survival, and local-regional relapse-free survival were calculated using the Kaplan-Meier method. Between December 2007 and March 2011, 18 patients were enrolled. The median age was 71.5 years. Primary disease was stages II, III, and IV in 3, 8, and 4 patients, respectively. There were three patients with recurrent disease after radical surgery. The median follow-up time was 17.2 months. Grade 3 esophagitis and skin rash were observed in five (27.8%) and two (11.1%) patients, respectively. Radiation pneumonitis of grades 2 and 5 was observed in one patient each. No grade 3/4 impaired liver function or hematological toxicity was observed. At 1 month after radiotherapy, two (11.1%) patients achieved complete response, 11 (61.1%) patients achieved partial response, and 5 (27.8%) patients had stable disease. The median time of overall survival and progression-free survival was 21.1 and 12 months, respectively. Two-year overall survival, progression-free survival, and local-regional relapse-free survival were 44.4%, 38.9%, and 66.7%, respectively. Five of six patients examined for epidermal growth factor receptor had high expression levels (3+). The relationship between epidermal growth factor receptor expression and treatment outcomes could not be concluded. For esophageal squamous cell carcinoma patients who cannot tolerate chemoradiotherapy, concurrent erlotinib and radiotherapy are tolerable and effective. Valuable markers to predict the effect of erlotinib should be exploited in future studies.

Convection-enhanced delivery improves distribution and efficacy of tumor-selective retroviral replicating vectors in a rodent brain tumor model

In the present study, we compared the therapeutic effect of tumor-selective retroviral replicating vectors (RRV) expressing the yeast cytosine deaminase (CD) delivered by CED or simple injection, followed by systemic administration of the pro-drug, 5-fluorocytosine (5-FC). Treatment with RRV-CD and systemic 5-FC significantly increased survival in rodent U87MG glioma model in comparison to controls (p<0.01). Interestingly, CED of RRV-CD followed by 5-FC further enhanced survival in this animal model in comparison to intra-tumoral injection of RRV-CD followed by systemic 5-FC (p<0.05). High expression levels of Ki-67 were found in untreated tumors compared to treated. Untreated tumors were also much larger than treated. CED resulted in excellent distribution of RRV while only partial distribution of RRV was obtained after injection. Furthermore, RRV-CD and cytosine deaminase were also found in tumors from treated rats at study end-points. These results demonstrated that RRV vectors may efficiently transduce and stably propagate in malignant human glioma, thereby achieving a significant in-situ amplification effect after initial administration. We conclude that delivery of RRV into the glioma by CED provides much wider vector distribution than simple, injection, and this correlated with better therapeutic outcomes.

Artificial permeability and antibonding magnetic resonance in a copper-structured metamaterial with symmetry-broken ring-plate resonators

We numerically investigate the antibonding magnetic resonance in a metamaterial composed of rings and plates, with a particular attention to the influence of broken structural symmetry on the Fano-type transmission spectrum as well as the resonant artificial permeability. From the simulation results, it is obvious that the antibonding magnetic resonance with strong magnetic-dipole coupling is responsible for the Fano-type profile, since an increase of the structural asymmetry extent to reduce the magnetic field confinement in one of the gaps will form, in contrary, a Lorentzian resonance dip. The dual excitation pathways, i.e., electric and magnetic resonances, at destructive interference are the underlying reason of the Fano-type transmission response. Additionally, the structural-asymmetry dependence of the artificial permeability shows that the broken symmetry can strongly modify the effective permeability due to the altering magnetic-dipole interactions. It is found that an anti-resonant curve of permeability versus frequency will be resulted in if significant symmetry-broken structure is introduced.

Magnetic properties of (Fe50Co50)(1-x)-Gdx thin films with diluted Gd doping

(Fe50Co50)(1-x)-Gdx thin films (30 nm) with x<15% deposited on silicon substrates by magnetron sputtering were investigated by X-ray diffraction, vibrating sample magnetometer, and ferromagnetic resonance. Theoretical fittings of the angular dependent ferromagnetic resonance field of the FeCoGd films have been performed using the Landau-Lifshitz equation It is found that the ferromagnetic resonance experimental data is well fitted by the theory and various magnetic properties have been extracted in accordance. The saturation magnetization decreases from 22750 Oe at x = 0% to 14079 Oe at x = 14% in the FeCo-Gd film, and the perpendicular magnetic anisotropy has changed from an easy film plane to an easy film normal geometry. The gyromagnetic ratio, as well as the Landé g factor, are found increased also with increasing Gd content, i.e. from g = 2.08 at x = 0% to g = 2.29 at x = 14%. An enhancement of the L-S coupling in the presence of a low Gd content has been concluded based on an observable increase from 0.011 at x = 12% up to 0.015 at x = 14% in the Gilbert damping.

Disruption of Type-I IFN pathway ameliorates preservation damage in mouse orthotopic liver transplantation via HO-1 dependent mechanism

Ischemia/reperfusion injury (IRI) remains unresolved problem in clinical organ transplantation. We analyzed the role of Type-I interferon (IFN) pathway in a clinically relevant murine model of extended hepatic cold preservation followed by orthotopic liver transplantation (OLT). Livers from Type-I IFN receptor (IFNAR) knockout (KO) or wild-type (WT) mice (C57/BL6) were harvested, preserved at 4°C in UW solution for 20 h and transplanted to groups of syngeneic IFNAR KO or WT recipients. Liver graft but not recipient IFNAR deficiency was required to consistently ameliorate IRI in OLTs. Indeed, disruption of Type-I IFN signaling decreased serum alanine aminotransferase (sALT) levels (p < 0.001), diminished Suzuki's score of histological OLT damage (p < 0.01) and improved 14-day survival (from 42%[5/12] in WT to 92%[11/12] in IFNAR KO; p < 0.05). Unlike in WT group, IFNAR deficiency attenuated OLT expression of TNF-α, IL-1β, IL-6, MCP-1, CXCL-10, ICAM-1; diminished infiltration by macrophages/PMNs; and enhanced expression of antioxidant HO-1/Nrf2. The frequency of TUNEL+ apoptotic cells and caspase-3 activity/expression selectively decreased in IFNAR KO group. Small interfering (si)RNA-directed targeting of HO-1 restored cardinal features of liver IRI in otherwise resistant IFNAR-deficient OLTs. Thus, intact Type-I IFN signaling is required for hepatic IRI, whereas HO-1 is needed for cytoprotection against innate immunity-dominated organ preservation damage in IFNAR-deficient liver transplants.