Intracellular DNA sensing by neutrophils and amplification of the innate immune response.

As the first responders, neutrophils lead the innate immune response to infectious pathogens and inflammation inducing agents. The well-established pathogen neutralizing strategies employed by neutrophils are phagocytosis, the action of microbicide granules, the production of ROS, and the secretion of neutrophil extracellular traps (NETs). Only recently, the ability of neutrophils to sense and respond to pathogen-associated molecular patterns is being appreciated. This review brings together the current information about the intracellular recognition of DNA by neutrophils and proposes models of signal amplification in immune response. Finally, the clinical relevance of DNA sensing by neutrophils in infectious and non-infectious diseases including malignancy are also discussed.

Quality of informed consent documents among US. hospitals: a cross-sectional study.

OBJECTIVE: To determine whether informed consent for surgical procedures performed in US hospitals meet a minimum standard of quality, we developed and tested a quality measure of informed consent documents. DESIGN: Retrospective observational study of informed consent documents. SETTING: 25 US hospitals, diverse in size and geographical region. COHORT: Among Medicare fee-for-service patients undergoing elective procedures in participating hospitals, we assessed the informed consent documents associated with these procedures. We aimed to review 100 qualifying procedures per hospital; the selected sample was representative of the procedure types performed at each hospital. PRIMARY OUTCOME: The outcome was hospital quality of informed consent documents, assessed by two independent raters using an eight-item instrument previously developed for this measure and scored on a scale of 0-20, with 20 representing the highest quality. The outcome was reported as the mean hospital document score and the proportion of documents meeting a quality threshold of 10. Reliability of the hospital score was determined based on subsets of randomly selected documents; face validity was assessed using stakeholder feedback. RESULTS: Among 2480 informed consent documents from 25 hospitals, mean hospital scores ranged from 0.6 (95% CI 0.3 to 0.9) to 10.8 (95% CI 10.0 to 11.6). Most hospitals had at least one document score at least 10 out of 20 points, but only two hospitals had >50% of their documents score above a 10-point threshold. The Spearman correlation of the measures score was 0.92. Stakeholders reported that the measure was important, though some felt it did not go far enough to assess informed consent quality. CONCLUSION: All hospitals performed poorly on a measure of informed consent document quality, though there was some variation across hospitals. Measuring the quality of hospital's informed consent documents can serve as a first step in driving attention to gaps in quality.

Myelin phagocytosis by astrocytes after myelin damage promotes lesion pathology.

Astrocytes are key players in the pathology of multiple sclerosis and can assume beneficial and detrimental roles during lesion development. The triggers and timing of the different astroglial responses in acute lesions remain unclear. Astrocytes in acute multiple sclerosis lesions have been shown previously to contain myelin debris, although its significance has not been examined. We hypothesized that myelin phagocytosis by astrocytes is an early event during lesion formation and leads to astroglial immune responses. We examined multiple sclerosis lesions and other central nervous system pathologies with prominent myelin injury, namely, progressive multifocal leukoencephalopathy, metachromatic leukodystrophy and subacute infarct. In all conditions, we found that myelin debris was present in most astrocytes at sites of acute myelin breakdown, indicating that astroglial myelin phagocytosis is an early and prominent feature. Functionally, myelin debris was taken up by astrocytes through receptor-mediated endocytosis and resulted in astroglial NF-κB activation and secretion of chemokines. These in vitro results in rats were validated in human disease where myelin-positive hypertrophic astrocytes showed increased nuclear localization of NF-κB and elevated chemokine expression compared to myelin-negative, reactive astrocytes. Thus, our data suggest that myelin uptake is an early response of astrocytes in diseases with prominent myelin injury that results in recruitment of immune cells. This first line response of astrocytes to myelin injury may exert beneficial or detrimental effects on the lesion pathology, depending on the inflammatory context. Modulating this response might be of therapeutic relevance in multiple sclerosis and other demyelinating conditions.

Quantitative susceptibility mapping (QSM) of white matter multiple sclerosis lesions: Interpreting positive susceptibility and the presence of iron.

PURPOSE: Within multiple sclerosis (MS) lesions iron is present in chronically activated microglia. Thus, iron detection with MRI might provide a biomarker for chronic inflammation within lesions. Here, we examine contributions of iron and myelin to magnetic susceptibility of lesions on quantitative susceptibility mapping (QSM). METHODS: Fixed MS brain tissue was assessed with MRI including gradient echo data, which was processed to generate field (phase), R2* and QSM. Five lesions were sectioned and evaluated by immunohistochemistry for presence of myelin, iron and microglia/macrophages. Two of the lesions had an elemental analysis for iron concentration mapping, and their phospholipid content was estimated from the difference in the iron and QSM data. RESULTS: Three of the five lesions had substantial iron deposition that was associated with microglia and positive susceptibility values. For the two lesions with elemental analysis, the QSM derived phospholipid content maps were consistent with myelin labeled histology. CONCLUSION: Positive susceptibility values with respect to water indicate the presence of iron in MS lesions, although both demyelination and iron deposition contribute to QSM.

B cells populating the multiple sclerosis brain mature in the draining cervical lymph nodes.

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by autoimmune-mediated demyelination and neurodegeneration. The CNS of patients with MS harbors expanded clones of antigen-experienced B cells that reside in distinct compartments including the meninges, cerebrospinal fluid (CSF), and parenchyma. It is not understood whether this immune infiltrate initiates its development in the CNS or in peripheral tissues. B cells in the CSF can exchange with those in peripheral blood, implying that CNS B cells may have access to lymphoid tissue that may be the specific compartment(s) in which CNS-resident B cells encounter antigen and experience affinity maturation. Paired tissues were used to determine whether the B cells that populate the CNS mature in the draining cervical lymph nodes (CLNs). High-throughput sequencing of the antibody repertoire demonstrated that clonally expanded B cells were present in both compartments. Founding members of clones were more often found in the draining CLNs. More mature clonal members derived from these founders were observed in the draining CLNs and also in the CNS, including lesions. These data provide new evidence that B cells traffic freely across the tissue barrier, with the majority of B cell maturation occurring outside of the CNS in the secondary lymphoid tissue. Our study may aid in further defining the mechanisms of immunomodulatory therapies that either deplete circulating B cells or affect the intrathecal B cell compartment by inhibiting lymphocyte transmigration into the CNS.

Chronic exposure to benzyl butyl phthalate (BBP) alters social interaction and fear conditioning in male adult rats: alterations in amygdalar MeCP2, ERK1/2 and ERα.

OBJECTIVES: Benzyl Butyl Phthalate (BBP) is an industrial plasticizer that has an unknown action in the central nervous system. Phthalates have recently been associated with behavioral actions that are linked to their endocrine disrupting properties. The purpose of this study was to investigate the behavioral and molecular effects of BBP treatment in male rats. DESIGN: Male rats were chronically exposed to BBP in the drinking water (5.0 ppm and 10.0 ppm) throughout adolescence and into the adult phase of life. Their behavior was then assessed in a learning and memory task (fear conditioning), open field exploration and a test of sociability. RESULTS: BBP treated rats showed decreased freezing in fear conditioning, no changes in open field exploration, and increased aberrant social behavior. Rats were sacrificed at post natal day 140 and blood and brains were harvested and processed. We found increased hormonally active estrogen, 17-ß estradiol, in the serum of BBP treated rats. BBP treatment also induced changes in amygdalar proteins related to synaptic plasticity including decreased MeCP2 levels that correlated with tests of sociability with no changes in stress related proteins such as nuclear factor kappa B (NFkB). We also found alterations in physiological responses as measured by body weight without changes in food consumption suggesting disruption of metabolism and body homeostasis. CONCLUSIONS: We suggest that BBP administration disrupts normal learning and social behavior, and that these effects could be related to alterations of amygdala function.

Role of PPARs in Radiation-Induced Brain Injury.

Whole-brain irradiation (WBI) represents the primary mode of treatment for brain metastases; about 200 000 patients receive WBI each year in the USA. Up to 50% of adult and 100% of pediatric brain cancer patients who survive >6 months post-WBI will suffer from a progressive, cognitive impairment. At present, there are no proven long-term treatments or preventive strategies for this significant radiation-induced late effect. Recent studies suggest that the pathogenesis of radiation-induced brain injury involves WBI-mediated increases in oxidative stress and/or inflammatory responses in the brain. Therefore, anti-inflammatory strategies can be employed to modulate radiation-induced brain injury. Peroxisomal proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the steroid/thyroid hormone nuclear receptor superfamily. Although traditionally known to play a role in metabolism, increasing evidence suggests a role for PPARs in regulating the response to inflammation and oxidative injury. PPAR agonists have been shown to cross the blood-brain barrier and confer neuroprotection in animal models of CNS disorders such as stroke, multiple sclerosis and Parkinson's disease. However, the role of PPARs in radiation-induced brain injury is unclear. In this manuscript, we review the current knowledge and the emerging insights about the role of PPARs in modulating radiation-induced brain injury.

The PPARalpha agonist fenofibrate preserves hippocampal neurogenesis and inhibits microglial activation after whole-brain irradiation.

PURPOSE: Whole-brain irradiation (WBI) leads to cognitive impairment months to years after radiation. Numerous studies suggest that decreased hippocampal neurogenesis and microglial activation are involved in the pathogenesis of WBI-induced brain injury. The goal of this study was to investigate whether administration of the peroxisomal proliferator-activated receptor (PPAR) alpha agonist fenofibrate would prevent the detrimental effect of WBI on hippocampal neurogenesis. METHODS AND MATERIALS: For this study, 129S1/SvImJ wild-type and PPARalpha knockout mice that were fed either regular or 0.2% wt/wt fenofibrate-containing chow received either sham irradiation or WBI (10-Gy single dose of (137)Cs gamma-rays). Mice were injected intraperitoneally with bromodeoxyuridine to label the surviving cells at 1 month after WBI, and the newborn neurons were counted at 2 months after WBI by use of bromodeoxyuridine/neuronal nuclei double immunofluorescence. Proliferation in the subgranular zone and microglial activation were measured at 1 week and 2 months after WBI by use of Ki-67 and CD68 immunohistochemistry, respectively. RESULTS: Whole-brain irradiation led to a significant decrease in the number of newborn hippocampal neurons 2 months after it was performed. Fenofibrate prevented this decrease by promoting the survival of newborn cells in the dentate gyrus. In addition, fenofibrate treatment was associated with decreased microglial activation in the dentate gyrus after WBI. The neuroprotective effects of fenofibrate were abolished in the knockout mice, indicating a PPARalpha-dependent mechanism or mechanisms. CONCLUSIONS: These data highlight a novel role for PPARalpha ligands in improving neurogenesis after WBI and offer the promise of improving the quality of life for brain cancer patients receiving radiotherapy.

PPARalpha ligands inhibit radiation-induced microglial inflammatory responses by negatively regulating NF-kappaB and AP-1 pathways.

Whole-brain irradiation (WBI) can lead to cognitive impairment several months to years after irradiation. Studies on rodents have shown a rapid and sustained increase in activated microglia (brain macrophages) following brain irradiation, contributing to a chronic inflammatory response and a corresponding decrease in hippocampal neurogenesis. Thus, alleviating microglial activation following radiation represents a key strategy to minimize WBI-induced morbidity. We hypothesized that pretreatment with peroxisomal proliferator-activated receptor (PPAR)alpha agonists would ameliorate the proinflammatory responses seen in the microglia following in vitro radiation. Irradiating BV-2 cells (a murine microglial cell line) with single doses (2-10 Gy) of (137)Cs gamma-rays led to increases in (1) the gene expression of IL-1beta and TNFalpha, (2) Cox-2 protein levels, and (3) intracellular ROS generation. In addition, an increase in the DNA-binding activity of redox-regulated proinflammatory transcription factors AP-1 and NF-kappaB was observed. Pretreating BV-2 cells with the PPARalpha agonists GW7647 and Fenofibrate significantly inhibited the radiation-induced microglial proinflammatory response, in part, via decreasing (i) the nuclear translocation of the NF-kappaB p65 subunit and (ii) phosphorylation of the c-jun subunit of AP-1 in the nucleus. Taken together, these data support the hypothesis that activation of PPARalpha can modulate the radiation-induced microglial proinflammatory response.

Heparin/heparan sulfate interacting protein plays a role in apoptosis induced by anticancer drugs.

Heparin/heparan sulfate interacting protein (HIP, also known as ribosome protein L29) is involved in cell-cell and cell-extracellular matrix interactions and influences cell proliferation, migration and differentiation. In the present study, we investigated the role of HIP in anticancer drug-induced apoptosis. Both colon cancer HCT-116 and HT-29 cells showed dose-dependent down-regulation of HIP expression when treated with sodium butyrate. The down-regulation was negatively correlated with the percentage of apoptotic cells (R = -0.955, P = 0.03 and R = -0.792, P = 0.06 for HCT-116 and HT-29 cells, respectively). The correlation between HIP expression and apoptosis in HCT-116 cells was also evident in the differential expression of HIP in the floating and adherent cell populations. Most apoptotic cells were distributed in the floating population. HIP expression in this population was approximately 30% lower than adherent and untreated control cells. HIP expression in HCT-116 cells was also significantly decreased in parallel with apoptosis after treatment with 50 micro M camptothecin and 20 micro M 5-fluorouracil. This indicates that the down-regulation of HIP may be a general phenomenon in anticancer drug-induced apoptosis. The down-regulation of HIP occurred in the early phase of apoptosis, in parallel with the activation of caspase-3 and the externalization of phosphatidylserine. The functional significance of HIP in apoptosis was shown by knocking down the expression of HIP using small interfering RNA. A 50% reduction in HIP expression was sufficient to increase the percentage of apoptotic cells (from 11 to 20%) and increase the sensitivity of the cells to apoptosis induced by 1 mM butyrate by 60%. These results indicate that HIP may play an important role in anticancer drug-induced apoptosis.

The proline-rich acidic protein is epigenetically regulated and inhibits growth of cancer cell lines.

The proline-rich acidic protein (PRAP) gene was found previously to be expressed in the epithelial cells of the mouse and rat gastrointestinal tracts, and pregnant mouse uterus. This article describes the isolation, distribution, and functional characterization of the human homologue. PRAP was abundantly expressed in the epithelial cells of the human liver, kidney, gastrointestinal tract, and cervix. PRAP expression was significantly down-regulated in hepatocellular carcinoma and right colon adenocarcinoma compared with the respective adjacent normal tissues. Treatment of the cells with butyrate, trichostatin A, and 5'-aza-2' deoxycytidine caused increases in PRAP gene expression of up to 30-fold, suggesting that the gene is suppressed through epigenetic mechanisms involving histone deacetylation and methylation. To determine the significance of PRAP expression in cancer cells, we cloned PRAP and its two major splice variants from human colon and liver, and overexpressed it in HeLa, HT29, and HepG2 cells. PRAP caused cell growth inhibition in the cancer cell lines in transient transfection assays, colony formation assays, and in the growth rates of stable clones. The data suggest that PRAP and its variants may play an important role in maintaining normal growth homeostasis in epithelial cells. The epigenetic suppression of PRAP expression in cancer may cause growth dysregulation, a hallmark of the carcinogenic process.