Peritonitis-induced peroxynitrite and lung damage depends on c-Jun NH2-terminal kinase signaling of hematopoietic cells

Targeting F-Box Protein Fbxo3 Attenuates Lung Injury Induced by Ischemia-Reperfusion in Rats

Background: Increasing evidence suggests that Fbxo3 signaling has an important impact on the pathophysiology of the inflammatory process. Fbxo3 protein inhibition has reduced cytokine-driven inflammation and improved disease severity in animal model of Pseudomonas-induced lung injury. However, it remains unclear whether inhibition of Fbxo3 protein provides protection in acute lung injury induced by ischemia-reperfusion (I/R). In this study, we investigated the protective effects of BC-1215 administration, a Fbxo3 inhibitor, on acute lung injury induced by I/R in rats.

Methods: Lung I/R injury was induced by ischemia (40 min) followed by reperfusion (60 min). The rats were randomly assigned into one of six experimental groups (n = 6 rats/group): the control group, control + BC-1215 (Fbxo3 inhibitor, 0.5 mg/kg) group, I/R group, or I/R + BC-1215 (0.1, 0.25, 0.5 mg/kg) groups. The effects of BC-1215 on human alveolar epithelial cells subjected to hypoxia-reoxygenation (H/R) were also examined.

Results: BC-1215 significantly attenuated I/R-induced lung edema, indicated by a reduced vascular filtration coefficient, wet/dry weight ratio, lung injury scores, and protein levels in bronchoalveolar lavage fluid (BALF). Oxidative stress and the level of inflammatory cytokines in BALF were also significantly reduced following administration of BC-1215. Additionally, BC-1215 mitigated I/R-stimulated apoptosis, NF-κB, and mitogen-activated protein kinase activation in the injured lung tissue. BC-1215 increased Fbxl2 protein expression and suppressed Fbxo3 and TNFR associated factor (TRAF)1–6 protein expression. BC-1215 also inhibited IL-8 production and NF-κB activation in vitro in experiments with alveolar epithelial cells exposed to H/R.

Conclusions: Our findings demonstrated that Fbxo3 inhibition may represent a novel therapeutic approach for I/R-induced lung injury, with beneficial effects due to destabilizing TRAF proteins.

PG490-88, a derivative of triptolide, suppresses ischemia/reperfusion-induced lung damage by maintaining tight junction barriers and targeting multiple signaling pathways

Previous studies demonstrated that triptolide (PG490) has many anti-inflammatory and immunosuppressive effects. However, little is known about the effect of PG490-88 (a water-soluble derivative of triptolide) on ischemia/reperfusion (I/R)-induced acute lung injury. We assessed the effects of PG490-88 on I/R-induced acute lung injury in rats and on hypoxia/reoxygenation (H/R) in a line of murine epithelial cells. Isolated perfused rat lungs were subjected to 40 min of ischemia, followed by 60 min of reperfusion to induce I/R injury. Induction of I/R led to lung edema, elevated pulmonary arterial pressure, histological evidence of lung inflammation, oxidative stress, and increased levels of TNF-α and CINC-1 in bronchoalveolar lavage fluid. PG490-88 significantly suppressed all of these responses. Additionally, induction of I/R reduced the expression of claudin-4, occludin, and ZO-1, and increased apoptosis in lung tissue. PG490-88 also significantly suppressed these effects. I/R reduced the levels of IκB-α and MKP-1, and increased the levels of nuclear NF-κB and mitogen-activated protein kinase in lung tissue, and PG490-88 suppressed these effects. In vitro studies using mouse lung alveolar epithelial cells indicated that H/R increased the levels of phosphorylated p65 and MIP-2, but decreased the level of IκB-α. PG490-88 also suppressed these effects. In I/R damaged lungs, PG490-88 suppresses the inflammatory response, disruption of tight junction structure, and apoptosis. PG490-88 has the potential as a prophylactic agent to prevent I/R-induced lung injury.

Targeting of nicotinamide phosphoribosyltransferase enzymatic activity ameliorates lung damage induced by ischemia/reperfusion in rats

Background

Emerging evidence reveals that nicotinamide phosphoribosyltransferase (NAMPT) has a significant role in the pathophysiology of the inflammatory process. NAMPT inhibition has a beneficial effect in the treatment of a variety of inflammatory diseases. However, it remains unclear whether NAMPT inhibition has an impact on ischemia-reperfusion (I/R)-induced acute lung injury. In this study, we examined whether NAMPT inhibition provided protection against I/R lung injury in rats.

Methods

Isolated perfused rat lungs were subjected to 40 min of ischemia followed by 60 min of reperfusion. The rats were randomly allotted to the control, control + FK866 (NAMPT inhibitor, 10 mg/kg), I/R, or I/R + FK866 groups (n = 6 per group). The effects of FK866 on human alveolar epithelial cells exposed to hypoxia-reoxygenation (H/R) were also investigated.

Results

Treatment with FK866 significantly attenuated the increases in lung edema, pulmonary arterial pressure, lung injury scores, and TNF-α, CINC-1, and IL-6 concentrations in bronchoalveolar lavage fluid in the I/R group. Malondialdehyde levels, carbonyl contents and MPO-positive cells in lung tissue were also significantly reduced by FK866. Additionally, FK866 mitigated I/R-stimulated degradation of IκB-α, nuclear translocation of NF-κB, Akt phosphorylation, activation of mitogen-activated protein kinase, and downregulated MKP-1 activity in the injured lung tissue. Furthermore, FK866 increased Bcl-2 and decreased caspase-3 activity in the I/R rat lungs. Comparably, the in vitro experiments showed that FK866 also inhibited IL-8 production and NF-κB activation in human alveolar epithelial cells exposed to H/R.

Conclusions

Our findings suggest that NAMPT inhibition may be a novel therapeutic approach for I/R-induced lung injury. The protective effects involve the suppression of multiple signal pathways.

Protection against reperfusion lung injury via aborgating multiple signaling cascades by trichostatin A

Trichostatin A (TSA) is a histone deacetylase inhibitor with anti-inflammatory effects. Nonetheless, little information is available about the effect of TSA in ischemia-reperfusion (IR)-induced lung injury. In a perfused rat lung model, IR was induced by 40min of ischemia followed by 60min of reperfusion. The rat lungs were randomly divided into several groups including control, control+TSA (0.1mg/kg), IR, and IR+various dosages of TSA (0.05, 0.075, 0.1mg/kg). Bronchoalveolar lavage fluids and lung tissues were obtained and examined at the end of the experiment. TSA dose-dependently diminished IR-induced increased vascular permeability and edema, pulmonary artery pressure, and histological changes in the lungs. Additionally, TSA suppressed lavage tumor necrosis factor-α and cytokine-induced neutrophil chemoattractant concentrations, cell infiltration, and myeloperoxidase-positive cells in the lung tissue. Furthermore, TSA attenuated the phosphorylation of extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase, degradation of the inhibitor of nuclear factor (NF)-κB, and nuclear NF-κB levels. TSA also decreased poly (ADP-ribose) polymerase but enhanced acetylated histone H3 acetylation, Bcl-2, and mitogen-activated protein kinase phosphatase-1 (MKP-1) expression in IR lung tissue. Therefore, TSA exerted a protective effect on IR-induced lung injury via increasing histone acetylation and MKP-1 protein expression, repressing NF-κB, mitogen-activated protein kinase, and apoptosis signaling pathways.

Exercise preconditioning protects against spinal cord injury in rats by upregulating neuronal and astroglial heat shock protein 72

The heat shock protein 72 (HSP 72) is a universal marker of stress protein whose expression can be induced by physical exercise. Here we report that, in a localized model of spinal cord injury (SCI), exercised rats (given pre-SCI exercise) had significantly higher levels of neuronal and astroglial HSP 72, a lower functional deficit, fewer spinal cord contusions, and fewer apoptotic cells than did non-exercised rats. pSUPER plasmid expressing HSP 72 small interfering RNA (SiRNA-HSP 72) was injected into the injured spinal cords. In addition to reducing neuronal and astroglial HSP 72, the (SiRNA-HSP 72) significantly attenuated the beneficial effects of exercise preconditioning in reducing functional deficits as well as spinal cord contusion and apoptosis. Because exercise preconditioning induces increased neuronal and astroglial levels of HSP 72 in the gray matter of normal spinal cord tissue, exercise preconditioning promoted functional recovery in rats after SCI by upregulating neuronal and astroglial HSP 72 in the gray matter of the injured spinal cord. We reveal an important function of neuronal and astroglial HSP 72 in protecting neuronal and astroglial apoptosis in the injured spinal cord. We conclude that HSP 72-mediated exercise preconditioning is a promising strategy for facilitating functional recovery from SCI.

Angiogenesis contributes to the neuroprotection induced by hyperbaric oxygen preconditioning against focal cerebral ischemia in rats

Ischemic stroke is one of the leading causes of mortality and disability worldwide. Previous studies have indicated that hyperbaric oxygen preconditioning (HBO-PC) can induce neuroprotection against focal cerebral ischemia. However, the underlying mechanisms are still not fully understood, and the optimal regimen for preconditioning must be confirmed. In the present study, we designed eight preconditioning regimens and compared their neuroprotective effects. Hyperbaric oxygen preconditioning every other day for there sessions exhibited the best neuroprotective effect; the infarct volume was reduced by almost 50% at 48 h after middle cerebral artery occlusion. We also found that HBO-PC significantly increased the microvessel density and the CD31-positive cells in the penumbra at 72 h after stroke. These results indicate that angiogenesis is involved in the neuroprotection induced by HBO-PC. Moreover, we explored the roles of HIF-1α and angiogenic factors in the angiogenesis process induced by HBO-PC. The results from western blotting demonstrated that protein expression of Ang-2 in the HBO-PC group was significantly increased. In conclusion, HBO-PC reduced brain injury and improved neurological function after focal cerebral ischemia, as partly mediated by the increased microvessel density in the penumbra, and this effect may result from the upregulation of Ang-2.

Comparison of skin and soft tissue infections caused by Vibrio and Aeromonas species

BACKGROUND

The aim of this study was to compare skin and soft tissue infections (SSTIs) caused by Vibrio and Aeromonas spp.

METHODS

Patients whose cultures yielded Vibrio or Aeromonas spp. from July 2004 to June 2010 were retrieved from the computerized database of the bacteriology laboratory at a hospital in southern Taiwan. The medical records were reviewed for all patients fulfilling the criteria of monomicrobial Vibrio or Aeromonas spp. SSTIs and the clinical characteristics were analyzed.

RESULTS

During the study period, there were 28 patients with Vibrio spp. and 26 patients with Aeromonas spp., respectively. Vibrio vulnificus (n=25) and A. hydrophila (n=14) were the most common spp. There were no significant differences in age, gender, underlying diseases between patients with Vibrio and Aeromonas SSTIs. In comparison to Aeromonas SSTIs, more patients with Vibrio SSTIs were complicated with acute respiratory failure (39.3% vs. 3.8%, p=0.002) and required intensive care unit admission (50.0% vs. 7.7%, p<0.001). Furthermore, patients with Aeromonas SSTIs had a higher likelihood of discharge alone within 30 days than Vibrio SSTIs (p=0.049). The difference in in-hospital mortality among the two groups was not statistically significant (p=0.11).

CONCLUSION

Both Aeromonas and Vibrio spp. cause SSTIs in southern Taiwan and the pathogenicity of Vibrio spp. might be higher than Aeromonas spp.

Toll-like receptor 4 gene polymorphisms and susceptibility to bladder cancer

Bladder cancer is one of the most common malignancies in the world. Toll-like receptor 4 (TLR4) plays important roles in regulating innate immunity and may affect the development of cancers. Polymorphisms in TLR4 gene have been shown to be associated with impaired immune responses. Here, we investigated the association of TLR4 polymorphisms with bladder cancer. Four TLR4 polymorphisms (-2242T/C, Asp299Gly, Thr399Il3, and +3725G/C) were genotyped in a total number of 436 bladder cancer patients and 522 healthy controls. Data were analyzed using the Chi-square test. Results showed that the prevalence of TLR4 +3725GC and CC genotypes were significantly increased in bladder cancer cases than in controls (odds ratio [OR] = 1.58, 95 % confidence interval [CI] = 1.19-2.10, p = 0.0015, and OR = 2.33, 95%CI = 1.52-3.58, p < 0.0001, respectively). Also, the frequency of TLR4 +3725C allele was significantly higher in bladder cancer patients (p < 0.0001). The -2242T/C, Asp299Gly and Thr399Il3 polymorphisms did not reveal any significant differences between cases and controls. Stratification analysis of the clinical features in the patients demonstrated that cases with invasive cancer were correlated with higher numbers of +3725GC and CC genotype (p = 0.0004 and p = 0.0231). In conclusion, these results indicate that TLR4 +3725G/C polymorphism may be a novel risk factor for bladder cancer in the Chinese population.

Histone deacetylase inhibitor treatment attenuates MAP kinase pathway activation and pulmonary inflammation following hemorrhagic shock in a rodent model

BACKGROUND

Hemorrhagic shock activates cellular stress signals and can lead to systemic inflammatory response, organ injury, and death. We have previously shown that treatment with histone deacetylase inhibitors (HDACIs) significantly improves survival in lethal models (60% blood loss) of hemorrhage. The aim of the current study was to examine whether these protective effects were due to attenuation of mitogen activated protein kinase (MAPK) signaling pathways, which are known to promote inflammation and apoptosis.

METHODS

Wistar-Kyoto rats (250-300 g) were subjected to 40% blood loss and randomized to treatment with: (1) HDACI valproic acid (VPA 300 mg/kg i.v.; volume = 0.75 mL/kg), or (2) vehicle control (0.75 mL/kg of 0.9% saline). Animals were sacrificed at 1, 4, and 20 h (n = 3-4/group/timepoint), and lung samples were analyzed by Western blotting for expression of active (phosphorylated) and inactive forms of c-Jun N-terminal Kinase (JNK) and p38 MAPK. Myeloperoxidase (MPO) activity was measured in lung tissue 20 h after hemorrhage as a marker of neutrophil infiltration. Normal animals (n = 3) served as shams.

RESULTS

Hemorrhaged animals demonstrated significant increases in phosphorylated p38 at 1 h, phosphorylated JNK at 4 h, and increased MPO activity at 20 h (P < 0.05 compared with sham). VPA treatment significantly (P < 0.05) attenuated all of these changes.

CONCLUSIONS

Hemorrhagic shock activates pro-inflammatory MAPK signaling pathways and promotes pulmonary neutrophil infiltration, affects that are significantly attenuated by VPA treatment. This may represent a key mechanism through which HDACIs decrease organ damage and promote survival in hemorrhagic shock.

Enteral arginine modulates inhibition of AP-1/c-Jun by SP600125 in the postischemic gut

We previously demonstrated that enteral arginine increased c-Jun/activator protein-1 (AP-1) DNA-binding activity and iNOS expression in a rodent model of mesenteric ischemia/reperfusion (I/R). The objective of this study was to specifically investigate the role of AP-1 in arginine's deleterious effect on the postischemic gut. We hypothesized that AP-1 inhibition would mitigate the effects of arginine. Using a rodent model of mesenteric I/R we demonstrated that gut neutrophil infiltration, activity of c-Jun/AP-1, as well as iNOS expression were increased by I/R and further increased by arginine while lessened by inhibition of c-Jun using the pharmacologic c-Jun N-terminal kinase inhibitor, SP600125. Similar results were demonstrated using a cell culture model of oxidant stress in IEC-6 cells. Importantly, effects of SP600125 were comparable to those of c-Jun silencing. Lastly, the specific iNOS inhibitor, 1400W, had no effect on either AP-1 or c-Jun. In conclusion, SP600125 attenuated the activity of c-Jun/AP-1, iNOS expression, and neutrophil infiltration induced by arginine following mesenteric I/R. Our data suggest that AP-1 inhibition mitigates the injurious inflammatory effects of arginine in the postischemic gut. Further investigation into the pathologic role of enteral arginine in the postischemic gut is warranted.