Abstract

The activation of oxidative damage, neuroinflammation, and mitochondrial dysfunction has been implicated in secondary pathomechanisms following spinal cord injury (SCI). These pathophysiological processes lead to cell death and are tightly regulated by nuclear factor E2-related factor 2/antioxidant response element (Nrf2/ARE) signaling. Here, we investigated whether activation of Nrf2/ARE is neuroprotective following SCI. Female Fischer rats were subjected to mild thoracic SCI (T8) using the New York University injury device. As early as 30 min after SCI, levels of Nrf2 transcription factor were increased in both nuclear and cytoplasmic fractions of neurons and astrocytes at the lesion site and remained elevated for 3 days. Treatment of injured rats with sulforaphane, an activator of Nrf2/ARE signaling, significantly increased levels of Nrf2 and glutamate-cysteine ligase (GCL), a rate-limiting enzyme for synthesis of glutathione, and decreased levels of inflammatory cytokines, interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) thus leading to a reduction in contusion volume and improvement in coordination. These results show that activation of the Nrf2/ARE pathway following SCI is neuroprotective and that sulforaphane is a viable compound for neurotherapeutic intervention in blocking pathomechanisms following SCI.

Spinal cord injury (SCI) induces a glial response in which astrocytes become activated and produce inflammatory mediators. The molecular basis for regulation of glial-innate immune responses remains poorly understood. Here, we examined the activation of retinoic acid inducible gene (RIG)-like receptors (RLRs) and their involvement in regulating inflammation following SCI. We show that astrocytes express two intracellular RLRs: RIG-I and melanoma differentiation-associated gene 5 (MDA5). SCI and stretch injury of cultured astrocytes stimulated RLR signaling as determined by phosphorylation of IRF3 leading to production of type I interferons (IFNs). RLR signaling stimulation with synthetic RNA resulted in RLR activation, phosphorylation of interferon regulatory factor 3 (IRF3), and increased expression of glial fibrillary acidic protein and vimentin, two hallmarks of reactive astrocytes. Moreover, mitochondrial E3 ubiquitin protein ligase 1 (MUL1), an RLR inhibitor, decreased production of glial fibrillary acidic protein (GFAP) and vimentin following RIG-I signaling stimulation. Our findings identify a role for RLR signaling and type I IFN in regulating astrocyte innate immune responses after SCI.

Objective

Reduced plasma adiponectin (APN) in diabetic patients is associated with endothelial dysfunction. However, APN knockout animals manifest modest systemic dysfunction unless metabolically challenged. The protein family CTRPs (C1q/TNF-related proteins) has recently been identified as APN paralogs and some CTRP members share APN’s metabolic regulatory function. However, the vasoactive properties of CTRPs remain completely unknown.

Methods and Results

The vasoactivity of currently identified murine CTRP members was assessed in aortic vascular rings and underlying molecular mechanisms was elucidated in HUVECs. Of eight CTRPs, CTRPs 3, 5, and 9 caused significant vasorelaxation. The vasoactive potency of CTRP9 exceeded that of APN (3-fold), and is endothelium-dependent and nitric oxide (NO) mediated. Mechanistically, CTRP9 increased AMPK/Akt/eNOS phosphorylation and increased NO production. AMPK knockdown completely blocked CTRP9-induced Akt/eNOS phosphorylation and NO production. Akt knockdown had no significant effect upon CTRP9-induced AMPK phosphorylation, but blocked eNOS phosphorylation and NO production. Adiponectin receptor 1 (AdipoR1), but not receptor 2, knockdown blocked CTRP9-induced AMPK/Akt/eNOS phosphorylation and NO production. Finally, pre-incubating vascular rings with an AMPK-inhibitor abolished CTRP9-induced vasorelaxive effects.

Conclusion

We have provided the first evidence that CTRP9 is a novel vasorelaxive adipocytokine which may exert vasculoprotective effects via the AdipoR1/AMPK/eNOS dependent/NO mediated signaling pathway.

Abstract

Diabetes exacerbates ischemic heart disease morbidity and mortality via incompletely understood mechanisms. Although adiponectin (APN) reduces myocardial ischemia/reperfusion (MI/R) injury in nondiabetic animals, whether APN's cardioprotective actions are altered in diabetes, a pathologic condition with endogenously reduced APN, has never been investigated. High-fat diet (HD)–induced diabetic mice and normal diet (ND) controls were subjected to MI via coronary artery ligation, and given vehicle or APN globular domain (gAPN, 2 μg/g) 10 min before reperfusion. Compared to ND mice (where gAPN exerted pronounced cardioprotection), HD mice manifested greater MI/R injury, and a tripled gAPN dose was requisite to achieve cardioprotective extent seen in ND mice (i.e., infarct size, apoptosis, and cardiac function). APN reduces MI/R injury via AMP-activated protein kinase (AMPK)–dependent metabolic regulation and AMPK-independent antioxidative/antinitrative pathways. Compared to ND, HD mice manifested significantly blunted gAPN-induced AMPK activation, basally and after MI/R (p < 0.05). Although both low- and high-dose gAPN equally attenuated MI/R-induced oxidative stress (i.e., NADPH oxidase expression and superoxide production) and nitrative stress (i.e., inducible nitric oxide synthase expression, nitric oxide production, and peroxynitrite formation) in ND mice, only high-dose gAPN efficaciously did so in HD mice. We demonstrate for the first time that HD-induced diabetes diminished both AMPK-dependent and AMPK-independent APN cardioprotection, suggesting an unreported diabetic heart APN resistance. Antioxid. Redox Signal. 15, 1779–1788.

It has been proved that Nrf2 depletion enhances inflammatory process through activation of NF-κB in the brain after TBI, but little is known about the relationship between Nrf2 and NF-κB in astrocytes after TBI. Hence, we used primary cultured astrocytes from either Nrf2 wildtype or knockout mice to study the influence of Nrf2 on the activation of NF-κB and expression of proinflammatory cytokines in a model of TBI in vitro. Primary cultured astrocytes were scratched to mimic the traumatic injury in vitro. Then the DNA-binding activity of NF-κB was evaluated by EMSA. The mRNA and protein levels of TNF-α, IL-1β, IL-6, and MMP9 were also evaluated. Gelatin zymography was performed to detect the activity of MMP9. The activity of NF-κB and expression of proinflammatory cytokines mentioned above were upregulated at 24 h after scratch. The expression and activity of MMP9 were also elevated. And such tendency was much more prominent in Nrf2 KO astrocytes than that in WT astrocytes. These results suggest that the absence of Nrf2 may induce more aggressive inflammation through activation of NF-κB and downstream proinflammatory cytokines in astrocytes.

Rationale

Activation of pro-survival kinases and subsequent nitric oxide (NO) production by certain G protein-coupled receptors (GPCRs) protects myocardium in ischemia-reperfusion injury (I/R) models. GPCR signaling pathways are regulated by GPCR kinases (GRKs) and GRK2 has been shown to be a critical molecule in normal and pathological cardiac function.

Objective

A loss of cardiac GRK2 activity is known to arrest progression of heart failure (HF), at least in part by normalization of cardiac β-adrenergic receptor (βAR) signaling. Chronic HF studies have been done with GRK2 knockout mice as well as expression of the βARKct, a peptide inhibitor of GRK2 activity. This study was conducted to examine the role of GRK2 and its activity during acute myocardial ischemic injury using an I/R model.

Methods and Results

We demonstrate, using cardiac-specific GRK2 and βARKct expressing transgenic mice, a deleterious effect of GRK2 on in vivo myocardial I/R injury with βARKct imparting cardioprotection. Post-I/R infarct size was greater in GRK2 overexpressing mice (45.0±2.8% vs. 31.3±2.3% in controls) and significantly smaller in βARKct mice (16.8±1.3%, p<0.05). Importantly, in vivo apoptosis was found to be consistent with these reciprocal effects on post-I/R myocardial injury when levels of GRK2 activity were altered. Moreover, these results were reflected by higher Akt activation and induction of NO production via βARKct and these anti-apoptotic/survival effects could be recapitulated in vitro. Interestingly, selective antagonism of β2ARs abolished βARKct-mediated cardioprotection suggesting that enhanced GRK2 activity on this GPCR is deleterious to cardiac myocyte survival.

Conclusion

The novel effect of reducing acute ischemic myocardial injury via increased Akt activity adds significantly to the therapeutic potential of GRK2 inhibition with the βARKct to not only chronic HF but also potentially in acute ischemic injury conditions.

Deficiency of adiponectin (APN), an adipocyte-derived vascular protective molecule, contributes to diabetic vascular injury. The current study determined whether obesity/hyperlipidemia may alter the vascular response to APN, and investigated the involved mechanisms and pathologic significance. Adult male Sprague-Dawley rats were fed a regular or high-fat diet (HF) for 4–16 weeks. Circulating APN levels, aortic pAMPK/AMPK, peNOS/eNOS, and APN receptor expression levels were determined. Compared to time-matched animals fed control diet, plasma APN levels in HF-diet animals were significantly increased at 8 weeks, and rapidly declined thereafter. Despite unchanged or elevated circulating APN levels, phosphorylated AMPK and eNOS in vascular tissue were significantly reduced at all observed time points. Recombinant full length APN (rAPN) induced AMPK/eNOS phosphorylation and vasodilatation were significantly reduced in 16-week obese/hyperlipidemic aortic segments. Vascular APN receptor 1 (AdipoR1) and receptor 2 (AdipoR2) expression were significantly reduced 16 weeks after HF-diet. Pre-incubation of rAPN with obese/hyperlipidemic plasma, but not with normal plasma, significantly reduced its AMPK and eNOS activation effect, and blunted its protective effect against TNFα-induced HUVEC apoptosis. This study demonstrated for the first time that obesity/hyperlipidemia reduces vascular responsiveness to APN. Modification/inactivation of APN by unidentified factors present in obese/hyperlipidemic plasma, decreased vascular AdipoR1/R2 expression, and reduced circulating APN levels contribute to reduced vascular responsiveness to APN at different stages of the obese condition. Reduced APN bioactivity allows unmitigated TNFα pro-apoptotic and pro-inflammatory actions, contributing to vascular injury in obesity/hyperlipidemia.

Eugenol, an essential oil component in plants, has been demonstrated to possess activity against both Gram-positive and Gram-negative bacteria. This study examined the influence that subinhibitory concentrations of eugenol may have on the expression of the major exotoxins produced by Staphylococcus aureus. The results from a tumor necrosis factor (TNF) release assay and a hemolysin assay indicated that S. aureus cultured with graded subinhibitory concentrations of eugenol (16 to 128 μg/ml) dose dependently decreased the TNF-inducing and hemolytic activities of culture supernatants. Western blot analysis showed that eugenol significantly reduced the production of staphylococcal enterotoxin A (SEA), SEB, and toxic shock syndrome toxin 1 (the key exotoxins to induce TNF release), as well as the expression of α-hemolysin (the major hemolysin to cause hemolysis). In addition, this suppression was also evaluated at the transcriptional level via real-time reverse transcription (RT)-PCR analysis. The transcriptional analysis indicated that 128 μg/ml of eugenol remarkably repressed the transcription of the S. aureus sea, seb, tst, and hla genes. According to these results, eugenol has the potential to be rationally applied on food products as a novel food antimicrobial agent both to inhibit the growth of bacteria and to suppress the production of exotoxins by S. aureus.

Background

The pathogenicity of staphylococcus aureus is dependent largely upon its ability to secrete a number of virulence factors, therefore, anti-virulence strategy to combat S. aureus-mediated infections is now gaining great interest. It is widely recognized that some plant essential oils could affect the production of staphylococcal exotoxins when used at subinhibitory concentrations. Perilla [Perilla frutescens (L.) Britton], a natural medicine found in eastern Asia, is primarily used as both a medicinal and culinary herb. Its essential oil (perilla oil) has been previously demonstrated to be active against S. aureus. However, there are no data on the influence of perilla oil on the production of S. aureus exotoxins.

Methodology/Principal Findings

A broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of perilla oil against S. aureus strains. Hemolysis, tumour necrosis factor (TNF) release, Western blot, and real-time RT-PCR assays were performed to evaluate the effects of subinhibitory concentrations of perilla oil on exotoxins production in S. aureus. The data presented here show that perilla oil dose-dependently decreased the production of α-toxin, enterotoxins A and B (the major staphylococcal enterotoxins), and toxic shock syndrome toxin 1 (TSST-1) in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA).

Conclusions/Significance

The production of α-toxin, SEA, SEB, and TSST-1 in S. aureus was decreased by perilla oil. These data suggest that perilla oil may be useful for the treatment of S. aureus infections when used in combination with β-lactam antibiotics, which can increase exotoxins production by S. aureus at subinhibitory concentrations. Furthermore, perilla oil could be rationally applied in food systems as a novel food preservative both to inhibit the growth of S. aureus and to repress the production of exotoxins, particularly staphylococcal enterotoxins.

Matrix metalloproteinase-9 (MMP-9) plays an important role in the acute periods of spinal cord injury (SCI), and its expression is related to the inflammation which could cause the disruption of the blood-spinal barrier (BBB). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that plays a crucial role in cytoprotection against inflammation. The present study investigated the role of Nrf2 in upregulating of nuclear factor kappa B (NF-κB) activity, tumor necrosis factor-α (TNF-α), and MMP-9 after SCI. Wild-type Nrf2 (+/+) and Nrf2-deficient (Nrf (−/−)) mice were subjected to an SCI model induced by the application of vascular clips (force of 10 g) to the dura after a three-level T8-T10 laminectomy. We detected the wet/dry weight ratio of impaired spinal cord tissue, the activation of NF-κB, the mRNA and protein levels of TNF-α and MMP-9, and the enzyme activity of MMP-9. Nrf2 (−/−) mice were demonstrated to have more spinal cord edema, NF-κB activation, TNF-α production, and MMP-9 expression after SCI compared with the wild-type controls. The results suggest that Nrf2 may play an important role in limiting the upregulation of NF-κB activity, TNF-α, and MMP-9 in spinal cord after SCI.

Purpose

To observe changes in audiology, intellectual development, behavior development, and physical growth during systematic follow-up of infants with asymptomatic congenital human cytomegalovirus (HCMV) infection.

Materials and Methods

Fifty-two infants diagnosed with asymptomatic congenital HCMV infection from July 2003 to July 2007 served as the infection group, and 21 healthy infants served as the control group. All infants were confirmed to have HCMV infection by Fluorescent Quantative polymerase chain reaction (FQ-PCR). In both the infection and control groups, the neonates and infants at 3 months, 6 months, and 1 year of age underwent examinations.

Results

1) 20 items of National Black Nurses Association (NBNA) scores of neonates 12-14 days after birth in 2 groups were 38.3 ± 1.95 and 38.5 ± 2.29, without significant differences. 2) Auditory test: 50 ears of 25 cases in the infection group showed abnormal auditory thresholds in V waves with an abnormal rate of 14%, while no abnormalities were found in 21 cases in the control group. 3) Mental and psychomotor development index scores in the control group (107.49 ± 11.31 and 107.19 ± 10.98) were compared with those in 41 asymptomatically infected infants at 1 year of age (107.21 ± 9.96 and 108.31 ± 11.25), and no statistically significant difference was noted.

Conclusion

1) An elevated threshold in the V wave was present in asymptomatically infected infants, but could not be detected through otoacoustic emission (OAE) screening. 2) Either in the neonatal or infant periods, asymptomatic congenital HCMV infection did not have a significant influence on nervous behavior or on physical and intellectual development.

A marine sulfate-reducing bacterium SRB-22 was isolated by means of the agar shake dilution method and identified as Desulfovibrio desulfuricans by morphological, physiological and biochemical characteristics and 16S rDNA analysis. In the bioassay, its extract showed broad-spectrum antimicrobial activity using the paper disc agar diffusion method. This isolate showed a different antimicrobial profile than either ampicillin or nystatin and was found to produce at least eight antimicrobial components by bioautography. Suitable fermentation conditions for production of the active constituents were determined to be 28 day cultivation at 25 °C to 30 °C with a 10% inoculation ratio. Under these conditions, the SRB-22 was fermented, extracted and chemically investigated. So far an antimicrobial compound, mono-n-butyl phthalate, and an inactive compound, thymine, have been isolated and characterized.

Inflammatory response plays an important role in the pathogenesis of secondary brain injury after traumatic brain injury (TBI). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that plays a crucial role in cytoprotection against inflammation. The present study investigated the role of Nrf2 in the cerebral upregulation of NF-κB activity, proinflammatory cytokine, and ICAM-1 after TBI. Wild-type Nrf2 (+/+) and Nrf2 (−/−)-deficient mice were subjected to a moderately severe weight-drop impact head injury. Electrophoretic mobility shift assays (EMSAs) were performed to analyze the activation of nuclear factor kappa B (NF-κB). Enzyme-linked immunosorbent assays were performed to quantify the production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). Immunohistochemistry staining experiments were performed to detect the expression of intercellular adhesion molecule-1 (ICAM-1). Nrf2 (−/−) mice were shown to have more NF-κB activation, inflammatory cytokines TNF-α, IL-1β and IL-6 production, and ICAM-1 expression in brain after TBI compared with their wild-type Nrf2 (+/+) counterparts. The results suggest that Nrf2 plays an important protective role in limiting the cerebral upregulation of NF-κB activity, proinflammatory cytokine, and ICAM-1 after TBI.

Background

The disabling chronic pain syndrome erythromelalgia (also termed erythermalgia) is characterized by attacks of burning pain in the extremities induced by warmth. Pharmacological treatment is often ineffective, but the pain can be alleviated by cooling of the limbs. Inherited erythromelalgia has recently been linked to mutations in the gene SCN9A, which encodes the voltage-gated sodium channel Nav1.7. Nav1.7 is preferentially expressed in most nociceptive DRG neurons and in sympathetic ganglion neurons. It has recently been shown that several disease-causing erythromelalgia mutations alter channel-gating behavior in a manner that increases DRG neuron excitability.

Results

Here we tested the effects of temperature on gating properties of wild type Nav1.7 and mutant L858F channels. Whole-cell voltage-clamp measurements on wild type or L858F channels expressed in HEK293 cells revealed that cooling decreases current density, slows deactivation and increases ramp currents for both mutant and wild type channels. However, cooling differentially shifts the midpoint of steady-state activation in a depolarizing direction for L858F but not for wild type channels.

Conclusion

The cooling-dependent shift of the activation midpoint of L858F to more positive potentials brings the threshold of activation of the mutant channels closer to that of wild type Nav1.7 at lower temperatures, and is likely to contribute to the alleviation of painful symptoms upon cooling in affected limbs in patients with this erythromelalgia mutation.