Spontaneous firing patterns in the medial geniculate nucleus in a guinea pig model of tinnitus

The mechanism of tinnitus, the perception of sound in the absence of acoustic stimulation, remains as yet unknown. It has been proposed that tinnitus is caused by altered spontaneous activity in the auditory pathway following cochlear damage in combination with inadequate gating at the level of the auditory thalamus, the medial geniculate nucleus (MGN). To investigate this further we made electrophysiological recordings in MGN of guinea pigs (n = 9) with and without tinnitus after acoustic trauma (continuous loud tone at 10 kHz, 124 dB SPL for 2 h). Parameters of interest were spontaneous tonic and burst firing. After acoustic trauma, 5 out of 9 guinea pigs developed signs of tinnitus as determined by the gap prepulse inhibition of acoustic startle. Spontaneous firing rates were significantly increased in the tinnitus animals as compared to the non-tinnitus animals and this change was specific to pure-tone responsive MGN neurons. However, burst firing parameters, including number of bursts per minute, burst duration, number of spikes in each burst, and percentage of spikes occurring in a burst, were not different between tinnitus and non-tinnitus animals. In addition, our data showed a strong dependence of spontaneous firing rates with heart rate, which implies that monitoring physiological status in animals is pertinent to obtaining reliable data when recording at higher levels of the auditory pathway. Our results suggest that increases in the tonic spontaneous fining rate of pure-tone responsive MGN neurons but not changes in burst firing parameters, are a robust neural signature of tinnitus in anaesthetised animals.

miR-145a Regulation of Pericyte Dysfunction in a Murine Model of Sepsis

BACKGROUND

Sepsis is a life-threatening systemic disease with severe microvascular dysfunction. Pericytes preserve vascular homeostasis. To our knowledge, the potential roles of microRNAs in sepsis-induced pericyte dysfunction have not been explored.

METHODS

We determined lung pericyte expression of miR-145a in cecal ligation and puncture (CLP)-induced sepsis. Mouse lung pericytes were isolated and transfected with a miR-145a mimic, followed by stimulation with lipopolysaccharide (LPS). We measured inflammatory cytokine levels. To assess the functions of miR-145a in vivo, we generated a pericyte-specific miR-145a-knockout mouse and determined sepsis-induced organ injury, lung and renal vascular leakage, and mouse survival rates. We used RNA sequencing and Western blotting to analyze the signaling pathways regulated by miR-145a.

RESULTS

CLP led to decreased miR-145a expression in lung pericytes. The miR-145a mimic inhibited LPS-induced increases in cytokines. In CLP-induced sepsis, pericytes lacking miR-145a exhibited increased lung and kidney vascular leakage and reduced survival rates. We found that miR-145a could suppress LPS-induced NF-κB activation. In addition, we confirmed that the transcription factor Friend leukemia virus integration 1 (Fli-1) is a target of miR-145a and that Fli-1 activates NF-κB signaling.

CONCLUSION

Our results demonstrated that pericyte miR-145a mediates sepsis-associated microvascular dysfunction, potentially by means of Fli-1-mediated modulation of NF-κB signaling.

Circulating miRNA 887 is differentially expressed in ARDS and modulates endothelial function

Circulating microRNAs (miRNAs) can be taken up by recipient cells and have been recently associated with the acute respiratory distress syndrome (ARDS). Their role in host predisposition to the syndrome is unknown. The objective of the study was to identify circulating miRNAs associated with the development of sepsis-related ARDS and examine their impact on endothelial cell gene expression and function. We determined miRNA levels in plasma collected from subjects during the first 24 h of admission to a tertiary intensive care unit for sepsis. A miRNA that was differentially expressed between subjects who did and did not develop ARDS was identified and was transfected into human pulmonary microvascular endothelial cells (HPMECs). RNA sequencing, in silico analysis, cytokine expression, and leukocyte migration assays were used to determine the impact of this miRNA on gene expression and cell function. In two cohorts, circulating miR-887-3p levels were elevated in septic patients who developed ARDS compared with those who did not. Transfection of miR-887-3p into HPMECs altered gene expression, including the upregulation of several genes previously associated with ARDS (e.g., CXCL10, CCL5, CX3CL1, VCAM1, CASP1, IL1B, IFNB, and TLR2), and activation of cellular pathways relevant to the response to infection. Functionally, miR-887-3p increased the endothelial release of chemokines and facilitated trans-endothelial leukocyte migration. Circulating miR-887-3p is associated with ARDS in critically ill patients with sepsis. In vitro, miR-887-3p regulates the expression of genes relevant to ARDS and neutrophil tracking. This miRNA may contribute to ARDS pathogenesis and could represent a novel therapeutic target.

Optimizing the design of invasive placebo interventions in randomized controlled trials

Background

Placebo‐controlled trials play an important role in the evaluation of healthcare interventions. However, they can be challenging to design and deliver for invasive interventions, including surgery. In‐depth understanding of the component parts of the treatment intervention is needed to ascertain what should, and should not, be delivered as part of the placebo. Assessment of risk to patients and strategies to ensure that the placebo effectively mimics the treatment are also required. To date, no guidance exists for the design of invasive placebo interventions. This study aimed to develop a framework to optimize the design and delivery of invasive placebo interventions in RCTs.

Methods

A preliminary framework was developed using published literature to: expand the scope of an existing typology, which facilitates the deconstruction of invasive interventions; and identify placebo optimization strategies. The framework was refined after consultation with key stakeholders in surgical trials, consensus methodology and medical ethics.

Results

The resulting DITTO framework consists of five stages: deconstruct treatment intervention into constituent components and co‐interventions; identify critical surgical element(s); take out the critical element(s); think risk, feasibility and role of placebo in the trial when considering remaining components; and optimize placebo to ensure effective blinding of patients and trial personnel.

Conclusion

DITTO considers invasive placebo composition systematically, accounting for risk, feasibility and placebo optimization. Use of the framework can support the design of high‐quality RCTs, which are needed to underpin delivery of healthcare interventions.

Exosomes from endothelial progenitor cells improve outcomes of the lipopolysaccharide-induced acute lung injury

Background

The acute respiratory distress syndrome (ARDS) is characterized by disruption of the alveolar-capillary barrier resulting in accumulation of proteinaceous edema and increased inflammatory cells in the alveolar space. We previously found that endothelial progenitor cell (EPC) exosomes prevent endothelial dysfunction and lung injury in sepsis in part due to their encapsulation of miRNA-126. However, the effects of EPC exosomes in acute lung injury (ALI) remain unknown.

Methods

To determine if EPC exosomes would have beneficial effects in ALI, intratracheal administration of lipopolysaccharide (LPS) was used to induce ALI in mice. Lung permeability, inflammation, and the role of miRNA-126 in the alveolar-epithelial barrier function were examined.

Results

The intratracheal administration of EPC exosomes reduced lung injury following LPS-induced ALI at 24 and 48 h. Compared to placebo, intratracheal administration of EPC exosomes significantly reduced the cell number, protein concentration, and cytokines/chemokines in the bronchoalveolar lavage fluid (BALF), indicating a reduction in permeability and inflammation. Further, EPC exosomes reduced myeloperoxidase (MPO) activity, lung injury score, and pulmonary edema, demonstrating protection against lung injury. Murine fibroblast (NIH3T3) exosomes, which do not contain abundant miRNA-126, did not provide these beneficial effects. In human small airway epithelial cells (SAECs), we found that overexpression of miRNA-126-3p can target phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2), while overexpression of miRNA-126-5p inhibits the inflammatory alarmin HMGB1 and permeability factor VEGFα. Interestingly, both miR-126-3p and 5p increase the expression of tight junction proteins suggesting a potential mechanism by which miRNA-126 may mitigate LPS-induced lung injury.

Conclusions

Our data demonstrated that human EPC exosomes are beneficial in LPS-induced ALI mice, in part through the delivery of miRNA-126 into the injured alveolus.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2339-3) contains supplementary material, which is available to authorized users.

Fli-1 transcription factor regulates the expression of caspase-1 in lung pericytes

Our previous data demonstrated that Friend leukemia virus integration 1 (Fli-1), an ETS transcription factor, governs pericyte loss and vascular dysfunction in cecal ligation and puncture-induced murine sepsis by regulating essential pyroptosis markers including caspase-1. However, whether Fli-1 regulates caspase-1 expression levels in vitro and how Fli-1 regulates caspase-1 remain unknown. Our present work further demonstrated that overexpressed Fli-1 significantly increased caspase-1 and IL-18 expression levels in cultured mouse lung pericytes. Bacterial outer membrane vesicles (OMVs) have been found to induce cell pyroptosis through transferring LPS intracellularly. Using OMVs to induce an in vitro model of pyroptosis, we observed that OMVs significantly increased protein levels of Fli-1 in mouse lung pericytes. Furthermore, knockdown of Fli-1 by siRNA blocked OMVs-induced caspase-1, caspase-11 and IL-18 expression levels. As caspase-1 was predicted as a potential target of Fli-1, we cloned murine caspase-1 promoter into a luciferase construct. Our data demonstrate for the first time that Fli-1 regulates caspase-1 expression by directly binding to its promoter regions measured by chromatin immunoprecipitation (ChIP) assay and luciferase reporter system. In summary, our findings demonstrated a novel role and mechanism of Fli-1 in regulating caspase-1 expression in lung pericytes.

Application of Deacetylated Poly-N-Acetyl Glucosamine Nanoparticles for the Delivery of miR-126 for the Treatment of Cecal Ligation and Puncture-Induced Sepsis

Sepsis is an acute inflammatory syndrome in response to infection. In some cases, excessive inflammation from sepsis results in endothelial dysfunction and subsequent increased vascular permeability leading to organ failure. We previously showed that treatment with endothelial progenitor cells, which highly express microRNA-126 (miR-126), improved survival in mice subjected to cecal ligation and puncture (CLP) sepsis. miRNAs are important regulators of gene expression and cell function, play a major role in endothelial homeostasis, and may represent an emerging therapeutic modality. However, delivery of miRNAs to cells in vitro and in vivo is challenging due to rapid degradation by ubiquitous RNases. Herein, we developed a nanoparticle delivery system separately combining deacetylated poly-N-acetyl glucosamine (DEAC-pGlcNAc) polymers with miRNA-126-3p and miRNA-126-5p and testing these combinations in vitro and in vivo. Our results demonstrate that DEAC-pGlcNAc polymers have an appropriate size and zeta potential for cellular uptake and when complexed, DEAC-pGlcNAc protects miRNA from RNase A degradation. Further, DEAC-pGlcNAc efficiently encapsulates miRNAs as evidenced by preventing their migration in an agarose gel. The DEAC-pGlcNAc-miRNA complexes were taken up by multiple cell types and the delivered miRNAs had biological effects on their targets in vitro including pERK and DLK-1. In addition, we found that delivery of DEAC-pGlcNAc alone or DEAC-pGlcNAc:miRNA-126-5p nanoparticles to septic animals significantly improved survival, preserved vascular integrity, and modulated cytokine production. These composite studies support the concept that DEAC-pGlcNAc nanoparticles are an effective platform for delivering miRNAs and that they may provide therapeutic benefit in sepsis.

Fli-1 Governs Pericyte Dysfunction in a Murine Model of Sepsis

Background

Pericytes are vascular mural cells and are embedded in the basement membrane of the microvasculature. Recent studies suggest a role for pericytes in lipopolysaccharide (LPS)-induced microvascular dysfunction and mortality, but the mechanisms of pericyte loss in sepsis are largely unknown.

Methods

By using a cecal ligation and puncture (CLP)-induced murine model of sepsis, we observed that CLP led to lung and renal pericyte loss and reduced lung pericyte density and pericyte/endothelial cell (EC) coverage.

Results

Up-regulated Friend leukemia virus integration 1 (Fli-1) messenger ribonucleic acid (RNA) and protein levels were found in lung pericytes from CLP mice in vivo and in LPS-stimulated lung pericytes in vitro. Knockout of Fli-1 in Foxd1-derived pericytes prevented CLP-induced pericyte loss, vascular leak, and improved survival. Disrupted Fli-1 expression by small interfering RNA inhibited LPS-induced inflammatory cytokines and chemokines in cultured lung pericytes. Furthermore, CLP-induced pericyte pyroptosis was mitigated in pericyte Fli-1 knockout mice.

Conclusions

Our findings suggest that Fli-1 is a potential therapeutic target in sepsis.

Exosomes from Endothelial Progenitor Cells Improve the Outcome of a Murine Model of Sepsis

Microvascular dysfunction leads to multi-organ failure and mortality in sepsis. Our previous studies demonstrated that administration of exogenous endothelial progenitor cells (EPCs) confers protection in sepsis as evidenced by reduced vascular leakage, improved organ function, and increased survival. We hypothesize that EPCs protect the microvasculature through the exosomes-mediated transfer of microRNAs (miRNAs). Mice were rendered septic by cecal ligation and puncture (CLP), and EPC exosomes were administered intravenously at 4 hr after CLP. EPC exosomes treatment improved survival, suppressing lung and renal vascular leakage, and reducing liver and kidney dysfunction in septic mice. EPC exosomes attenuated sepsis-induced increases in plasma levels of cytokines and chemokine. Moreover, we determined miRNA contents of EPC exosomes with next-generation sequencing and found abundant miR-126-3p and 5p. We demonstrated that exosomal miR-126-5p and 3p suppressed LPS-induced high mobility group box 1 (HMGB1) and vascular cell adhesion molecule 1 (VCAM1) levels, respectively, in human microvascular endothelial cells (HMVECs). Inhibition of microRNA-126-5p and 3p through transfection with microRNA-126-5p and 3p inhibitors abrogated the beneficial effect of EPC exosomes. The inhibition of exosomal microRNA-126 failed to block LPS-induced increase in HMGB1 and VCAM1 protein levels in HMVECs and negated the protective effect of exosomes on sepsis survival. Thus, EPC exosomes prevent microvascular dysfunction and improve sepsis outcomes potentially through the delivery of miR-126.

Randomized feasibility trial of replacing or discarding the nail plate after nail-bed repair in children

BACKGROUND

Nail-bed injuries are the most common hand injury in children. Surgical dogma is to replace the nail plate after repairing the nail bed. Recent evidence suggests this might increase infection rates and returns to clinic. The aim of this feasibility trial was to inform the design and conduct of a definitive trial comparing replacing or discarding the nail plate after nail-bed repair.

METHODS

This study recruited participants from four hand units in the UK between April and July 2015. Participants were children under the age of 16 years with a nail-bed injury requiring surgery. They were randomized to either having the nail plate replaced or discarded after nail-bed repair. The follow-up method was also allocated randomly (postal versus clinic). Information was collected on complications at 2 weeks and 30 days, and on nail-plate appearance at 4 months using the Zook classification. Two possible approaches to follow-up were also piloted and compared.

RESULTS

During the recruitment phase, there were 156 potentially eligible children. Sixty were randomized in just over 3 months using remote web-based allocation. By 2 weeks, there were two infections, both in children with replaced nail plates. The nail-replaced group also experienced more complications. There was no evidence of a difference in return rates between postal and clinic follow-up.

CONCLUSION

Recruitment was rapid and nail-bed repair appeared to have low complication and infection rates in this pilot trial. The findings have led to revision of the definitive trial protocol, including the mode and timing of follow-up, and modification of the Zook classification.

Considerations for the design, analysis and presentation of in vivo studies

OBJECTIVE

To describe, explain and give practical suggestions regarding important principles and key methodological challenges in the study design, statistical analysis, and reporting of results from in vivo studies.

CONCLUSIONS

Pre-specifying endpoints and analysis, recognizing the common underlying assumption of statistically independent observations, performing sample size calculations, and addressing multiplicity issues are important parts of an in vivo study. A clear reporting of results and informative graphical presentations of data are other important parts.

The role of miRNAs in cardiovascular disease risk factors

Coronary artery disease and atherosclerosis are complex pathologies that develop over time due to genetic and environmental factors. Differential expression of miRNAs has been identified in patients with coronary artery disease and atherosclerosis, however, their association with cardiovascular disease risk factors, including hyperlipidemia, hypertension, obesity, diabetes, lack of physical activity and smoking, remains unclear. This review examines the role of miRNAs as either biomarkers or potential contributors to the pathophysiology of these aforementioned risk factors. It is intended to provide an overview of the published literature which describes alterations in miRNA levels in both human and animal studies of cardiovascular risk factors and when known, the possible mechanism by which these miRNAs may exert either beneficial or deleterious effects. The intent of this review is engage clinical, translational, and basic scientists to design future collaborative studies to further elucidate the potential role of miRNAs in cardiovascular diseases.

Implication of G i proteins and Src tyrosine kinases in endotoxin-induced signal transduction events and mediator production

Previous studies have suggested that heterotrimeric G proteins and tyrosine kinases may be involved in lipopolysaccharide (LPS) signaling events. Signal transduction pathways activated by LPS were examined in human promonocytic THP-1 cells. We hypothesized that Gi proteins and Src tyrosine kinase differentially affect mitogen-activated protein (MAP) kinases (MAPK) and nuclear factor kappa (NF- B) activation. Post-receptor coupling to G i proteins were examined using pertussis toxin (PTx), which inhibits G i receptor-coupling. The involvement of the Src family of tyrosine kinases was examined using the selective Src tyrosine kinase inhibitor pyrazolopyrimidine-2 (PP2). Pretreatment of THP-1 cells with PTx attenuated LPS-induced activation of c-Jun-N-terminal kinase (JNK) and p38 kinase, and production of tumor necrosis factor-alpha (TNF-) and thromboxane B2 (TxB2). Pretreatment with PP2 inhibited TNF- and TxB2 production, but had no effect on p38 kinase or JNK signaling. Therefore, the G i-coupled signaling pathways and Src tyrosine kinase-coupled signaling pathways are necessary for LPS-induced TNF- and TxB2 production, but differ in their effects on MAPK activation. Neither PTx nor PP2 inhibited LPS-induced activation of interleukin receptor activated kinase (IRAK) or inhibitedtranslocation of NF- B. However, PP2 inhibitedLPS-inducedNF-B transactivation of a luciferase reporter gene construct in a concentration-dependent manner. Thus, LPS induction of Src tyrosine kinases may be essential in downstream NF- B transactivation of genes following DNA binding. PTx had no effect on NF- B activation of the reporter construct. These data suggest upstream divergence in signaling through G i pathways leading to MAPK activation and other signaling events leading to I B degradation and NF- B DNA binding.

Endotoxin-induced cross-tolerance to Gram-positive sepsis

The manifestations of Gram-positive sepsis and Gram-negative sepsis share some common clinical features suggesting common pathways of activation. The goal of this study was to assess whether lipopolysaccharide (LPS) can produce cross-tolerance to Gram-positive sepsis induced by group B streptococcus (GBS). Thromboxane (TxB2), tumor necrosis factor (TNFα), and nitric oxide (NO) production by in vitro LPS- and heat killed GBS-stimulated rat peritoneal macrophages were measured. Since our previous studies have demonstrated altered macrophage activation of extracellular signal-regulated kinases 1 and 2 (ERK 1/2) in tolerance, we also examined the effect of LPS and killed GBS on ERK 1/2 activation in normal and LPS tolerant macrophages. Tolerance was induced in rats by intraperitoneal injection of Salmonella enteritidis LPS or vehicle for two consecutive days at doses of 0.1 and 0.5 mg/kg body weight. Three days after the second LPS dose, rats were injected intravenously with viable GBS (5 x l09 cfu/kg) and D-galactosamine (1 g/kg). LPS tolerance significantly prolonged ( P <0.05) mean survival time to severe GBS sepsis in D-galactosamine sensitized rats from 12.9 ± 1.7 h in control rats to 44.0 ± 8.9 h in tolerant rats. Peritoneal macrophages from LPS tolerant rats exhibited suppressed LPS induced in vitro TxB2 and TNFα production ( P <0.05). Tolerance also decreased in vitro heat killed GBS-induced TNFα production, but did not significantly affect TxB2 production. NO production stimulated by LPS (10 µg/ml was not impaired in LPS tolerance; however at lower doses (0.02—1.25 µg/ml), NO production was significantly decreased ( P <0.05). NO production was augmented ( P <0.05) in response to stimulation with GBS (10 µg/ml) and unaltered at lower doses (0.02—1.25 µg/ml) in tolerant cells. LPS activated ERK 1/2 in control macrophages, but activation of ERK 1/2 was suppressed in LPS tolerance. GBS did not significantly affect ERK 1/2 activity in control or tolerant macrophages. Nevertheless, the selective mitogen-activated kinase (MAPK)/ERK kinase (MEK) inhibitor, PD 98059 blocked ( P <0.05) both GBS- and LPS-induced TNFα and TxB2 production, but not NO production. Thus, some level of ERK 1/2 activity appears essential for GBS- and LPS-induced macrophage activation. In conclusion, LPS tolerance induces partial cross-tolerance to Gram-positive sepsis induced lethality, and alters LPS- and GBS-induced in vitro peritoneal macrophage mediator production. This suggests common pathways of cellular activation for GBS and LPS that are altered by LPS tolerance.

Review: Molecular mechanisms of endotoxin tolerance

The phenomenon of endotoxin tolerance has been widely investigated, but to date, the molecular mechanisms of endotoxin tolerance remain to be resolved clearly. The discovery of the Toll-like receptor (TLR) family as the major receptors for lipopolysaccharide (LPS) and other bacterial products has prompted a resurgence of interest in endotoxin tolerance mechanisms. Changes of cell surface molecules, signaling proteins, pro-inflammatory and anti -inflammatory cytokines and other mediators have been examined. During tolerance expression of LPS-binding protein (LBP), CD14, myeloid differentiation protein-2 (MD-2) and TLR2 are unchanged or up-regulated, whereas TLR4 is transiently suppressed or unchanged. Proximal post-receptor signaling proteins that are altered in tolerance include augmented degradation of interleukin-1 receptor-associated kinase (IRAK), and decreased TLR4-myeloid differentiation factor 88 (MyD88) and IRAK-MyD88 association. Tolerance has also been shown to be associated with decreased Gi protein content and activity, decreased protein kinase C (PKC) activity, reduction in mitogen-activated protein kinase (MAP kinase) activity, and reduced activator protein-1 (AP-1) and nuclear factor kappa B (NF-κB) induced gene transactivation. However, not all signaling proteins and pathways are suppressed in tolerance and induction of specific anti-inflammatory proteins and signaling pathways may serve important counter inflammatory functions. The latter include induction of IRAK-M and suppressor of cytokine-signaling-1 (SOCS-1), phosphoinositide-3-kinase (PI3K) signaling, and increased or maintained expression of inhibitor-κB (IκB) isoforms. Also at the nuclear level, increase in the NFκB subunit p50 homodimer expression and increased activation of peroxisome-proliferatoractivated receptors-γ (PPARγ) have been linked to tolerance phenotype. Although there are species and cellular variations in manifestation of the LPS tolerant phenotype, it is clear that the tolerance phenomena have evolved as a complex orchestrated counter regulatory response to inflammation.

Standardizing and monitoring the delivery of surgical interventions in randomized clinical trials

Background

The complexity of surgical interventions has major implications for the design of RCTs. Trials need to consider how and whether to standardize interventions so that, if successful, they can be implemented in practice. Although guidance exists for standardizing non‐pharmaceutical interventions in RCTs, their application to surgery is unclear. This study reports new methods for standardizing the delivery of surgical interventions in RCTs.

Methods

Descriptions of 160 surgical interventions in existing trial reports and protocols were identified. Initially, ten reports were scrutinized in detail using a modified framework approach for the analysis of qualitative data, which informed the development of a preliminary typology. The typology was amended with iterative sequential application to all interventions. Further testing was undertaken within ongoing multicentre RCTs.

Results

The typology has three parts. Initially, the overall technical purpose of the intervention is described (exploration, resection and/or reconstruction) in order to establish its constituent components and steps. This detailed description of the intervention is then used to establish whether and how each component and step should be standardized, and the standards documented within the trial protocol. Finally, the typology provides a framework for monitoring the agreed intervention standards during the RCT. Pilot testing within ongoing RCTs enabled standardization of the interventions to be agreed, and case report forms developed to capture deviations from these standards.

Conclusion

The typology provides a framework for use during trial design to standardize the delivery of surgical interventions and document these details within protocols. Application of this typology to future RCTs may clarify details of the interventions under evaluation and help successful interventions to be implemented.

Design a perfect study

Characterization of LY3023414, a Novel PI3K/mTOR Dual Inhibitor Eliciting Transient Target Modulation to Impede Tumor Growth

The PI3K/AKT/mTOR pathway is among the most frequently altered pathways in cancer cell growth and survival. LY3023414 is a complex fused imidazoquinolinone with high solubility across a wide pH range designed to inhibit class I PI3K isoforms and mTOR kinase. Here, we describe the in vitro and in vivo activity of LY3023414. LY3023414 was highly soluble at pH 2-7. In biochemical testing against approximately 266 kinases, LY3023414 potently and selectively inhibited class I PI3K isoforms, mTORC1/2, and DNA-PK at low nanomolar concentrations. In vitro, inhibition of PI3K/AKT/mTOR signaling by LY3023414 caused G₁ cell-cycle arrest and resulted in broad antiproliferative activity in cancer cell panel screens. In vivo, LY3023414 demonstrated high bioavailability and dose-dependent dephosphorylation of PI3K/AKT/mTOR pathway downstream substrates such as AKT, S6K, S6RP, and 4E-BP1 for 4 to 6 hours, reflecting the drug's half-life of 2 hours. Of note, equivalent total daily doses of LY3023414 given either once daily or twice daily inhibited tumor growth to similar extents in multiple xenograft models, indicating that intermittent target inhibition is sufficient for antitumor activity. In combination with standard-of-care drugs, LY3023414 demonstrated additive antitumor activity. The novel, orally bioavailable PI3K/mTOR inhibitor LY3023414 is highly soluble and exhibits potent in vivo efficacy via intermittent target inhibition. It is currently being evaluated in phase I and II trials for the treatment of human malignancies. Mol Cancer Ther; 15(10); 2344-56. ©2016 AACR.

Plasma levels of microRNA are altered with the development of shock in human sepsis: an observational study

Background

Endothelial dysfunction plays a critical role in the development of sepsis-related organ failure; however, the mechanisms that govern its development are not fully understood. Endothelial progenitor cells (EPCs) reduce vascular leak and organ failure in experimental sepsis while modulating plasma expression of microRNA (miRNA). MicroRNAs are small, noncoding segments of RNA that regulate gene expression and are known to modulate endothelial cell function and inflammatory signaling pathways. We hypothesized that miRNA may play an etiologic role in the endothelial dysfunction of sepsis and that their extracellular expression levels would be altered in those with shock.

Methods

Thirteen miRNAs were identified by literature search and analysis of the contents of human EPC-derived exosomes using real-time PCR. Plasma samples were obtained from patients within 24 hours of their admission to ICUs with severe sepsis (n = 62) and from healthy controls (n = 32) and real-time PCR was used to measure the expression of the candidate miRNAs. The Wilcoxon rank sum test was used to compare expression levels of the 13 candidate miRNAs in septic patients with (n = 29) and without (n = 33) shock while logistic regression was used to determine the area under the curve for associations between miRNA expression and shock. Bioinformatic analyses using miRNA databases were performed to identify pathways and gene targets of differentially expressed miRNA with potential relevance to sepsis-related shock.

Results

MiRNA-34a expression was significantly increased in the group who developed shock (p = 0.03) while miR-15a and miR-27a expressions were significantly decreased in this group (p = 0.006 and 0.03, respectively). The combined expression of these three miRNAs predicted shock with an area under the curve of 0.78 (95 % CI 0.66–0.90). In silico analyses predict that these three miRNAs regulate genes involved in endothelial cell cycle, apoptosis, VEGF signaling, LPS-stimulated MAPK signaling, and nuclear factor kappa B signaling.

Conclusions

The plasma levels of miRNA are altered in patients with severe sepsis complicated by shock and may offer prognostic value as well as insights into the mechanisms of endothelial dysfunction in sepsis.

Systematic review of intervention design and delivery in pragmatic and explanatory surgical randomized clinical trials

BACKGROUND

Surgical interventions are complex, with multiple components that require consideration in trial reporting. This review examines the reporting of details of surgical interventions in randomized clinical trials (RCTs) within the context of explanatory and pragmatic study designs.

METHODS

Systematic searches identified RCTs of surgical interventions published in 2010 and 2011. Included studies were categorized as predominantly explanatory or pragmatic. The extent of intervention details in the reports were compared with the CONSORT statement for reporting trials of non-pharmacological treatments (CONSORT-NPT). CONSORT-NPT recommends reporting the descriptions of surgical interventions, whether they were standardized and adhered to (items 4a, 4b and 4c). Reporting of the context of intervention delivery (items 3 and 15) and operator expertise (item 15) were assessed.

RESULTS

Of 4541 abstracts and 131 full-text articles, 80 were included (of which 39 were classified as predominantly pragmatic), reporting 160 interventions. Descriptions of 129 interventions (80.6 per cent) were provided. Standardization was mentioned for 47 (29.4 per cent) of the 160 interventions, and 22 articles (28 per cent) reported measurement of adherence to at least one aspect of the intervention. Seventy-one papers (89 per cent) provided some information about context. For one-third of interventions (55, 34.4 per cent), some data were provided regarding the expertise of personnel involved. Reporting standards were similar in trials classified as pragmatic or explanatory.

CONCLUSION

The lack of detail in trial reports about surgical interventions creates difficulties in understanding which operations were actually evaluated. Methods for designing and reporting surgical interventions in RCTs, contributing to the quality of the overall study design, are required. This should allow better implementation of trial results into practice.

Age-dependent therapeutic effects of liver X receptor-α activation in murine polymicrobial sepsis

The severity of sepsis is significantly affected by advanced age; however, age-dependent molecular mechanisms of this susceptibility are unknown. Nuclear liver X receptor-α (LXRα) is a regulator of lipid metabolism with associated anti-inflammatory properties. Here, we investigated the role of LXRα in age-dependent lung injury and outcome of sepsis. Male C57BL/6, LXRα-deficient (LXRα^−/−) and wild type (WT) (LXRα^+/+) mice of different ages were subjected to sepsis by cecal ligation and puncture (CLP). In pharmacological studies, treatment with the LXRα ligand T0901317 reduced lung neutrophil infiltration in C57BL/6 mice aged from 1 to 8 mo when compared with vehicle-treated animals subjected to CLP. The LXRα ligand improved survival in young mice (2–3 mo old) but did not affect survival or neutrophil infiltration in mature adult mice (11–13 mo old). Immunoblotting revealed an age-dependent decrease of lung LXRα levels. Young LXRα^−/− mice (2–3 mo old) exhibited earlier mortality than age-matched WT mice after CLP. Lung damage and neutrophil infiltration, lung activation of the pro-inflammatory NF-κB and plasma IL-6 levels were higher in LXRα^−/− mice 18 h after CLP compared with LXRα^+/+ mice. This study suggests that the anti-inflammatory properties of LXRα in sepsis are age-dependent and severely compromised in mature adult animals.

The rise of big clinical databases

BACKGROUND

The routine collection of large amounts of clinical data, 'big data', is becoming more common, as are research studies that make use of these data source. The aim of this paper is to provide an overview of the uses of data from large multi-institution clinical databases for research.

METHODS

This article considers the potential benefits, the types of data source, and the use to which the data is put. Additionally, the main challenges associated with using these data sources for research purposes are considered.

RESULTS

Common uses of the data include: providing population characteristics; identifying risk factors and developing prediction (diagnostic or prognostic) models; observational studies comparing different interventions; exploring variation between healthcare providers; and as a supplementary source of data for another study. The main advantages of using such big data sources are their comprehensive nature, the relatively large number of patients they comprise, and the ability to compare healthcare providers. The main challenges are demonstrating data quality and confidently applying a causal interpretation to the study findings.

CONCLUSION

Large clinical database research studies are becoming ubiquitous and offer a number of potential benefits. However, the limitations of such data sources must not be overlooked; each research study needs to be considered carefully in its own right, together with the justification for using the data for that specific purpose.

Combined treatment with a CXCL12 analogue and antibiotics improves survival and neutrophil recruitment and function in murine sepsis

Previous studies demonstrated that the CXCL12 peptide analogue CTCE-0214 (CTCE) has beneficial effects in experimental sepsis induced by cecal ligation and puncture (CLP). We examined the hypothesis that CTCE recruits neutrophils (PMN) to the site of infection, enhances PMN function and improves survival of mice in CLP-induced sepsis with antibiotic treatment. Septic mice (n=15) were administered imipenem (25mg/kg) and CTCE (10 mg/kg) subcutaneously vs. vehicle control at designated intervals post-CLP. CTCE treatment increased PMN recruitment in CLP-induced sepsis as evidenced by increased PMN in blood by 2.4±0.6 fold at 18h, 2.9±0.6 fold at 24h, respectively and in peritoneal fluid by 2.0±0.2 fold at 24h vs. vehicle control. CTCE treatment reduced bacterial invasion in blood (CFU decreased 77±11%), peritoneal fluid (CFU decreased 78±9%) and lung (CFU decreased 79±8% vs. CLP vehicle). The improved PMN recruitment and bacterial clearance correlated with reduced mortality with CTCE treatment (20% vs. 67% vehicle controls). In vitro studies support the notion that CTCE augments PMN function by enhancing phagocytic activity (1.25±0.02 fold), increasing intracellular production of ROS (32±4%) and improving bacterial killing (CFU decreased 27±3%). These composite findings support the hypothesis that specific CXCL12 analogues with ancillary antibiotic treatment are beneficial in experimental sepsis, in part, by augmenting PMN recruitment and function. This article is protected by copyright. All rights reserved.

Endothelial progenitor cells and a stromal cell-derived factor-1α analogue synergistically improve survival in sepsis

RATIONALE

Endothelial progenitor cells (EPCs) have been associated with human sepsis but their role is incompletely understood. Stromal cell-derived factor (SDF)-1α facilitates EPC recruitment and is elevated in murine sepsis models. Previous studies have demonstrated that the SDF-1α analog CTCE-0214 (CTCE) is beneficial in polymicrobial sepsis induced by cecal ligation and puncture (CLP) in mice.

OBJECTIVES

We hypothesized that exogenously administered EPCs are also beneficial in CLP sepsis and that CTCE provides synergistic benefit.

METHODS

Mice were subjected to CLP and administered EPCs at varying doses, CTCE, or a combination of the two. Mouse survival, plasma miRNA expression, IL-10 production, and lung vascular leakage were determined. The in vitro effect of CTCE on miRNA expression and EPC function were determined.

MEASUREMENTS AND MAIN RESULTS

Survival was improved with EPC therapy at a threshold of 10(6) cells. In coculture studies, EPCs augmented LPS-induced macrophage IL-10 production. In vivo EPC administration in sepsis increased plasma IL-10, suppressed lung vascular leakage, attenuated liver and kidney injury, and augmented miR-126 and -125b expression, which regulate endothelial cell function and/or inflammation. When subthreshold numbers of EPCs were coadministered with CTCE in CLP mice they synergistically improved survival. We demonstrated that CTCE recruits endogenous EPCs in septic mice. In in vitro analysis, CTCE enhanced EPC proliferation, angiogenesis, and prosurvival signaling while inhibiting EPC senescence. These cellular effects were, in part, explained by the effect of CTCE on miR-126, -125b, -34a, and -155 expression in EPCs.

CONCLUSIONS

EPCs and CTCE represent important potential therapeutic strategies in sepsis.

Beneficial effect of a CXCR4 agonist in murine models of systemic inflammation

The chemokine CXC receptor 4 (CXCR4) is activated by stromal cell-derived factor (SDF-1α). CXCR4 may be part of a lipopolysaccharide (LPS) sensing co-clustering complex that modulates TLR4 activation and evidence suggest that SDF-1α can activate anti-inflammatory signaling pathways and suppress inflammation. In the present study we examined the hypothesis that the SDF-1α peptide analog and CXCR4 agonist CTCE-0214 is anti-inflammatory in three distinct models of murine systemic inflammation. Our findings demonstrate that CTCE-0214 in vivo significantly suppressed plasma tumor necrosis factor alpha (TNF-α) increases in acute endotoxemia and following zymosan-induced multiple organ dysfunction syndrome (MODS). In both models, CTCE-0214 did not suppress plasma increases in the anti-inflammatory cytokine interleukin (IL)-10. CTCE-0214 improved survival without antibiotics in a model of severe sepsis induced by cecal ligation and puncture (CLP). CTCE-0214 also decreased plasma increases in IL-6 but not TNF-α and IL-10 in response to CLP-induced inflammation. We demonstrated in a moderately severe model of CLP (one puncture) that IL-6 levels at 24 h were similar to sham controls. However in severe CLP (two punctures) plasma IL-6 levels were markedly elevated. Plasma SDF-1α levels varied inversely with the plasma IL-6. In addition to the beneficial effect of CTCE-0214 in these models of systemic inflammation in vivo, we also demonstrated that the analog dose dependently suppressed LPS-induced IL-6 production in bone marrow-derived macrophages. CTCE-0214 therefore may be beneficial in controlling inflammation sepsis and systemic inflammatory syndromes.

Heterotrimeric Gα(i) proteins are regulated by lipopolysaccharide and are anti-inflammatory in endotoxemia and polymicrobial sepsis

Previous studies have implicated a role of heterotrimeric Gα(i) proteins in lipopolysaccharide (LPS)-induced inflammatory responses. We hypothesized that Toll-like receptor (TLR) signaling regulates Gα(i) proteins, which are anti-inflammatory in endotoxemia and polymicrobial sepsis. RAW 264.7 cells were stimulated with LPS and the Gα(i)-GTP protein complex was immunoprecipitated with a Gα(i) protein activation assay. In subsequent in vivo studies, the Gα(i) protein inhibitor pertussis toxin (PTx) or G(i) protein agonist mastoparan (MP-7) were administrated prior to endotoxemia. LPS-induced pro-inflammatory cytokines and mortality were determined. To examine the role of Gα(i2) in sepsis, Gα(i2) (-/-) and wildtype (WT) mice were subjected to cecal ligation and puncture (CLP) and monitored every 24 h for 120 h. Other mice were sacrificed 24 h after CLP. Peritoneal fluid, blood, and tissue samples were collected. Plasma pro-inflammatory cytokine production, bacterial load in peritoneal fluid, blood and lung tissue, myeloperoxidase (MPO) activity in lung and liver and different immune cell populations in spleen were studied. We found that Gα(i) proteins are rapidly activated by LPS followed by rapid inactivation. These studies provide the first direct evidence that Gα(i) proteins are modulated by TLR signaling. In following studies, PTx augmented LPS-induced plasma TNFα, IL-6, whereas MP-7 suppressed LPS-induced TNFα and decreased LPS-induced mortality. In sepsis studies, the survival rate post-CLP was significantly decreased in the Gα(i2) (-/-) mice compared to WT mice. CLP-induced plasma TNFα, IL-6, bacterial load in peritoneal fluid, blood and lung tissue and lung and liver MPO activity were significantly increased in Gα(i2) (-/-) compared to WT mice. Gα(i2) (-/-) mice also exhibited increased Th1 and Th2 responses compared to WT mice. Taken together, Gα(i) proteins are activated by LPS and negatively regulate endotoxemia and sepsis. Understanding the role of Gα(i2) protein in regulation of the inflammatory response in sepsis may provide novel targets for treatment of sepsis.

Peroxisome proliferator-activated receptor {delta} regulates inflammation via NF-{kappa}B signaling in polymicrobial sepsis

The nuclear peroxisome proliferator-activated receptor δ (PPARδ) is an important regulator of lipid metabolism. In contrast to its known effects on energy homeostasis, its biological role on inflammation is not well understood. We investigated the role of PPARδ in the modulation of the nuclear factor-κB (NF-κB)-driven inflammatory response to polymicrobial sepsis in vivo and in macrophages in vitro. We demonstrated that administration of GW0742, a specific PPARδ ligand, provided beneficial effects to rats subjected to cecal ligation and puncture, as shown by reduced systemic release of pro-inflammatory cytokines and neutrophil infiltration in lung, liver, and cecum, when compared with vehicle treatment. Molecular analysis revealed that treatment with GW0742 reduced NF-κB binding to DNA in lung and liver. In parallel experiments, heterozygous PPARδ-deficient mice suffered exaggerated lethality when subjected to cecal ligation and puncture and exhibited severe lung injury and higher levels of circulating tumor necrosis factor-α (TNFα) and keratinocyte-derived chemokine than wild-type mice. Furthermore, in lipopolysaccharide-stimulated J774.A1 macrophages, GW0742 reduced TNFα production by inhibiting NF-κB activation. RNA silencing of PPARδ abrogated the inhibitory effects of GW0742 on TNFα production. Chromatin immunoprecipitation assays revealed that PPARδ displaced the NF-κB p65 subunit from the κB elements of the TNFα promoter, while recruiting the co-repressor BCL6. These data suggest that PPARδ is a crucial anti-inflammatory regulator, providing a basis for novel sepsis therapies.

Randomized controlled trial comparing rubber band ligation with stapled haemorrhoidopexy for Grade II circumferential haemorrhoids: long-term results

OBJECTIVE

An improved understanding of the pathophysiology of haemorrhoids has resulted in the introduction of new surgical techniques including stapled haemorrhoidopexy (SH). This randomized controlled trial compared the long-term effectiveness of SH with rubber band ligation (RBL) in the treatment of grade II circumferential symptomatic haemorrhoids.

METHOD

A consecutive cohort of patients was randomly allocated to either SH or RBL. Data on haemorrhoidal symptoms, Cleveland continence scores, sphincter assessment, SF-36, EQ-5D, HAD score and prior treatment history were assessed at enrollment and reassessed by long-term postal questionnaire. The details were analysed using spss 12.0 from Microsoft Access.

RESULTS

Sixty patients were allocated by computer block randomization. Both groups were balanced for age, sex and symptoms. Recurrence favoured SH [3 vs 11; OR 0.18, 95% CI (0.03 to 0.86), P = 0.028] at 1 year and, at a mean of 40.67 (31-47) months [4 vs 12; OR 0.23, 95% CI (0.05, 0.95); P = 0.039]. SH patients experienced prolonged pain [Median (IQR) = 7 (5,7) vs 3 (1,7), P = 0.008] and took a longer time to return to work [6 (3,7) vs 3 (1,6) days, P = 0.018]. This was no significant difference in quality of life.

CONCLUSION

Stapled haemorrhoidopexy achieved better disease control at 1 year without any major complication. This was sustained in the long-term. Further studies with greater patient numbers are needed to confirm this study.

Beta-arrestin 2 negatively regulates sepsis-induced inflammation

SUMMARY

Beta-arrestins 1 and 2 are ubiquitously expressed proteins that alter signalling by G-protein-coupled receptors. beta-arrestin 2 plays an important role as a signalling adaptor and scaffold in regulating cellular inflammatory responses. We hypothesized that beta-arrestin 2 is a critical modulator of inflammatory response in experimental sepsis. beta-arrestin 2(-/-) and wild-type (WT) mice were subjected to caecal ligation and puncture (CLP). The survival rate was significantly decreased (P < 0.05) in beta-arrestin 2(-/-) mice (13% survival) compared with WT mice (53% survival). A second group of mice were killed 18 hr after CLP for blood, peritoneal lavage and tissue sample collection. CLP-induced plasma interleukin (IL)-6 was significantly increased 25 +/- 12 fold and caecal myeloperoxidase (MPO) activity was increased 2.4 +/- 0.3 fold in beta-arrestin 2(-/-) compared with WT mice. beta-arrestin 2(-/-) mice exhibited more severe lung damage and higher bacterial loads compared with WT mice post CLP challenge as measured by histopathology and colony-forming unit count. In subsequent experiments, splenocytes, peritoneal macrophages and bone marrow-derived macrophages (BMDMs) were isolated and cultured from beta-arrestin 2(-/-) and WT mice and stimulated in vitro with lipopolysaccharide (LPS). Tumour necrosis factor (TNF)-alpha, IL-6 and IL-10 production induced by LPS was significantly augmented (2.2 +/- 0.2 fold, 1.8 +/- 0.1 fold, and 2.2 +/- 0.4 fold, respectively; P < 0.05) in splenocytes from beta-arrestin 2(-/-) mice compared with WT mice. The splenocyte response was different from that of peritoneal macrophages or BMDMs, which exhibited no difference in TNF-alpha and IL-6 production upon LPS stimulation between WT and beta-arrestin 2(-/-) mice. Our data demonstrate that beta-arrestin 2 functions to negatively regulate the inflammatory response in polymicrobial sepsis.

Clinical outcomes from a randomised comparison of Microwave Endometrial Ablation with Thermal Balloon endometrial ablation for the treatment of heavy menstrual bleeding

OBJECTIVE

To compare the clinical outcomes of microwave endometrial ablation and thermal balloon ablation for the treatment of heavy menstrual bleeding.

DESIGN

A double blind randomised controlled trial.

SETTING

A UK teaching hospital.

POPULATION

Three hundred and twenty women requesting endometrial ablation.

METHODS

Operative data collection and patient completed postal questionnaires were used to ascertain women's satisfaction with outcome, acceptability of each procedure, changes in menstrual symptoms and health related quality of life and additional treatments received.

MAIN OUTCOME MEASURES

Primary outcomes were satisfaction and menstrual scores 1 year. Secondary outcomes were operative differences, acceptability of treatment and changes in health related quality of life.

RESULTS

Both technologies achieved high levels of satisfaction (-1%, 95% CI (-11, 9)). Menstrual scores were also similar (4%, 95% CI (-7, 19)) Microwave had a significantly shorter operating time, reduced usage of antiemetics and opiate analgesia, increased discharge by 6 hours and fewer device failures.

CONCLUSIONS

Both treatments are acceptable to women, with high levels of satisfaction. Microwave is quicker to perform with faster hospital discharge.

Lysophosphatidic acid inhibits bacterial endotoxin-induced pro-inflammatory response: potential anti-inflammatory signaling pathways

Previous studies have demonstrated that heterotrimeric guanine nucleotide-binding regulatory (Gi) protein-deficient mice exhibit augmented inflammatory responses to lipopolysaccharide (LPS). These findings suggest that Gi protein agonists will suppress LPS-induced inflammatory gene expression. Lysophosphatidic acid (LPA) activates G protein-coupled receptors leading to Gi protein activation. We hypothesized that LPA will inhibit LPS-induced inflammatory responses through activation of Gi-coupled anti-inflammatory signaling pathways. We examined the anti-inflammatory effect of LPA on LPS responses both in vivo and in vitro in CD-1 mice. The mice were injected intravenously with LPA (10 mg/kg) followed by intraperitoneal injection of LPS (75 mg/kg for survival and 25 mg/kg for other studies). LPA significantly increased the mice survival to endotoxemia (P < 0.05). LPA injection reduced LPS-induced plasma TNF-alpha production (69 +/- 6%, P < 0.05) and myeloperoxidase (MPO) activity in lung (33 +/- 9%, P < 0.05) as compared to vehicle injection. LPS-induced plasma IL-6 was unchanged by LPA. In vitro studies with peritoneal macrophages paralleled results from in vivo studies. LPA (1 and 10 microM) significantly inhibited LPS-induced TNFalpha production (61 +/- 9% and 72 +/- 9%, respectively, P < 0.05) but not IL-6. We further demonstrated that the anti-inflammatory effect of LPA was reversed by ERK 1/2 and phosphatase inhibitors, suggesting that ERK 1/2 pathway and serine/threonine phosphatases are involved. Inhibition of phosphatidylinositol 3 (PI3) kinase signaling pathways also partially reversed the LPA anti-inflammatory response. However, LPA did not alter NFkappaB and peroxisome proliferator-activated receptor gamma (PPARgamma) activation. Inhibitors of PPARgamma did not alter LPA-induced inhibition of LPS signaling. These studies demonstrate that LPA has significant anti-inflammatory activities involving activation of ERK 1/2, serine/threonine phosphatases, and PI3 kinase signaling pathways.

64-Slice computed tomography angiography in the diagnosis and assessment of coronary artery disease: systematic review and meta-analysis

CONTEXT

Coronary artery disease (CAD) is a major cause of mortality and ill health.

OBJECTIVE

To assess whether 64-slice CT angiography might replace some coronary angiography (CA) for diagnosis and assessment of CAD.

DATA SOURCES

Electronic databases, conference proceedings and reference lists of included studies.

STUDY SELECTION

Eligible studies compared 64-slice CT with a reference standard of CA in adults with suspected/known CAD, reporting sensitivity and specificity or true and false positives and negatives.

DATA EXTRACTION

Two reviewers independently extracted data from included studies.

RESULTS

Forty studies were included; 28 provided sufficient data for inclusion in the meta-analyses, all using a cut off point of >/=50% stenosis to define significant CAD. In patient-based detection (n = 1286) 64-slice CT pooled sensitivity was 99% (95% credible interval (CrI) 97% to 99%), specificity 89% (95% CrI 83% to 94%), median positive predictive value (PPV) across studies 93% (range 64-100%) and negative predictive value (NPV) 100% (range 86-100%). In segment-based detection (n = 14 199) 64-slice CT pooled sensitivity was 90% (95% CrI 85% to 94%), specificity 97% (95% CrI 95% to 98%), median PPV across studies 76% (range 44-93%) and NPV 99% (range 95-100%).

CONCLUSIONS

64-Slice CT is highly sensitive for patient-based detection of CAD and has high NPV. An ability to rule out significant CAD means that it may have a role in the assessment of chest pain, particularly when the diagnosis remains uncertain despite clinical evaluation and simple non-invasive testing.

beta-Arrestin 2: a Negative Regulator of Inflammatory Responses in Polymorphonuclear Leukocytes

Heterotrimeric Gi proteins have been previously implicated in signaling leading to inflammatory mediator production induced by bacterial lipopolysaccharide (LPS). beta-arrestins are ubiquitously expressed proteins that alter G-protein-coupled receptors signaling. beta-arrestin 2 plays a multifaceted role as a scaffold protein in regulating cellular inflammatory responses. Polymorphonuclear leukocytes (PMNs) activated by LPS induce inflammatory responses resulting in organ injury during sepsis. We hypothesized that beta-arrestin 2 is a critical modulator of inflammatory responses in PMNs. To examine the potential role of beta-arrestin 2 in LPS-induced cellular activation, we studied homozygous beta-arrestin 2 (-/-), heterozygous (+/-), and wildtype (+/+) mice. PMNs were stimulated with LPS for 16h. There was increased basal TNFalpha and IL-6 production in the beta-arrestin 2 (-/-) compared to both beta-arrestin 2 (+/-) and (+/+) cells. LPS failed to stimulate TNFalpha production in the beta-arrestin 2 (-/-) PMNs. However, LPS stimulated IL-6 production was increased in the beta-arrestin 2 (-/-) cells compared to (+/+) cells. In subsequent studies, peritoneal PMN recruitment was increased 81% in the beta-arrestin 2 (-/-) mice compared to (+/+) mice (p<0.05). beta-arrestin 2 deficiency resulted in an augmented expression of CD18 and CD62L (p<0.05). In subsequent studies, beta-arrestin 2 (-/-) and (+/+) mice were subjected to cecal ligation and puncture (CLP) and lung was collected and analyzed for myeloperoxidase activity (MPO) as index of PMNs infiltrate. CLP-induced MPO activity was significantly increased (p<0.05) in the beta-arrestin 2 (-/-) compared to (+/+) mice. These studies demonstrate that beta-arrestin 2 is a negative regulator of PMN activation and pulmomary leukosequestration in response to polymicrobial sepsis.

Species of coccidia (Apicomplexa: Eimeriidae) infecting pikas from Alaska, U.S.A. and northeastern Siberia, Russia

Eighty-eight fecal samples from 2 species of pika, Ochotona collaris and Ochotona hyperborea, collected in Alaska (N = 53) and Russia (N = 35), respectively, were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Five oocyst morphotypes were observed. In O. collaris, we found Eitmeria calentinei, Eimeria cryptobarretti, and Eimeria klondikensis, whereas in O. hyperborea, we found Eimeria banffensis, E. calentinei, E. cryptobarretti, E. klondikensis, and Isospora marquardti. This study represents new geographic records for all 5 coccidia and new host records for E. cryptobarretti and I. marquardti. Only minor quantitative differences were seen between the sporulated oocysts we studied and those reported in their original descriptions.

Comparative phylogeography and demographic history of the wood lemming (Myopus schisticolor): implications for late Quaternary history of the taiga species in Eurasia

The association between demographic history, genealogy and geographical distribution of mitochondrial DNA cytochrome b haplotypes was studied in the wood lemming (Myopus schisticolor), a species that is closely associated with the boreal forest of the Eurasian taiga zone from Scandinavia to the Pacific coast. Except for a major phylogeographic discontinuity (0.9% nucleotide divergence) in southeastern Siberia, only shallow regional genetic structure was detected across northern Eurasia. Genetic signs of demographic expansions imply that successive range contractions and expansions on different spatial scales represented the primary historical events that shaped geographical patterns of genetic variation. Comparison of phylogeographic structure across a taxonomically diverse array of other species that are ecologically associated with the taiga forest revealed similar patterns and identified two general aspects. First, the major south-north phylogeographic discontinuity observed in five out of six species studied in southeastern Siberia and the Far East implies vicariant separation in two different refugial areas. The limited distribution range of the southeastern lineages provides no evidence of the importance of the putative southeastern refugial area for postglacial colonization of northern Eurasia by boreal forest species. Second, the lack of phylogeographic structure associated with significant reciprocal monophyly and genetic signatures of demographic expansion in all nine boreal forest animal species studied to date across most of northern Eurasia imply contraction of each species to a single refugial area during the late Pleistocene followed by range expansion on a continental scale. Similar phylogeographic patterns observed in this taxonomically diverse set of organisms with different life histories and dispersal potentials reflect the historical dynamics of their shared environment, the taiga forest in northern Eurasia.

PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR γ IS REQUIRED FOR THE INHIBITORY EFFECT OF CIGLITAZONE BUT NOT 15-DEOXY-Δ12,14-PROSTAGLANDIN J2 ON THE NFκB PATHWAY IN HUMAN ENDOTHELIAL CELLS

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-activated nuclear receptor with effects on inflammation, atherosclerosis, and apoptosis. The endogenous PPARgamma ligand, 15-deoxy-Delta12,14-PGJ2 (15d-PGJ2), and the synthetic ligand, ciglitazone, have anti-inflammatory properties in endothelial cells. In addition to PPARgamma-dependent effects on the anti-inflammatory process, it has been proposed that PPARgamma ligands may also inhibit the nuclear transcription factor kappaB (NFkappaB) pathway in a PPARgamma-independent manner. The purpose of this study was to compare the effects of 15d-PGJ2 and ciglitazone on the cytokine-induced activation of the NFkappaB pathway. Human umbilical vein endothelial cells (HUVECs) were transiently transfected with NFkappaB-luciferase or PPARgamma elements-luciferase reporter constructs for 48 h. The HUVECs were pretreated with 15d-PGJ2 or ciglitazone (30 microM) for 1 h, followed by a 4-h stimulation with tumor necrosis factor alpha (100 U/mL). Luciferase assay was performed to determine reporter activity. Additionally, HUVECs were transiently transfected with a dominant-negative mutant, which retains ligand and DNA binding but exhibits markedly reduced transactivation. Stimulation of HUVEC with tumor necrosis factor alpha increased NFkappaB activation while decreasing PPARgamma activity. Overexpression of a dominant-negative PPARgamma mutant prevented the inhibitory effect of ciglitazone on cytokine-induced NFkappaB activation in transfected human endothelial cells. Conversely, 15d-PGJ2 inhibited the cytokine-induced NFkappaB activation even in the absence of PPARgamma. Our data suggest that 15d-PGJ2 exerts direct inhibitory effects on the NFkappaB pathway through a PPARgamma-independent mechanism. On the contrary, the inhibitory effect of ciglitazone on the NFkappaB pathway seems to require PPARgamma activation.

Peroxisome proliferator activated receptor gamma is not necessary for the development of LPS-induced tolerance in macrophages

Peroxisome proliferator activated receptor-gamma (PPARgamma) has been reported to exert anti-inflammatory properties in endotoxic shock and sepsis. One phenomenon that alters the inflammatory response to endotoxin [lipopolysaccharide (LPS)] is endotoxin tolerance, which is caused by previous exposure to endotoxin. Here, we investigate whether changes in endogenous PPARgamma function regulate this phenomenon using three different models of LPS-induced tolerance in macrophages. In a first in vitro model, previous LPS exposure of murine J774.2 macrophages suppressed tumour necrosis factor-alpha (TNF-alpha) release in response to subsequent LPS challenge. Treatment of J774.2 cells with the PPARgamma inhibitor GW9662 did not alter tolerance induction because these cells were still hyporesponsive to the secondary LPS challenge. In a second ex vivo model, primary rat peritoneal macrophages from LPS-primed rats exhibited suppression of thromboxane B2 and TNF-alpha production, while maintaining nitrite production in response to in vitro LPS challenge. Pretreatment of rats with the PPARgamma inhibitor GW9662 in vivo failed to alter the tolerant phenotype of these primary macrophages. In a third ex vivo model, primary peritoneal macrophages with conditional deletion of PPARgamma were harvested from LPS-primed Cre-lox mice (Cre+/+ PPARgamma-/-) and exhibited significant suppression of TNF-alpha production in response to in vitro LPS challenge. Furthermore, both LPS-primed PPARgamma-deficient Cre+/+ PPARgamma-/- mice and wild-type Cre-/- PPARgamma+/+ mice exhibited reduced plasma TNF-alpha levels in response to a high dose of LPS in vivo. These data demonstrate that PPARgamma does not play a role in the LPS-induced tolerant phenotype in macrophages.

Differential regulation of lipopolysaccharide and Gram-positive bacteria induced cytokine and chemokine production in macrophages by Galpha(i) proteins

Heterotrimeric G(i) proteins play a role in signalling activated by lipopolysaccharide (LPS), Staphylococcus aureus (SA) and group B streptococci (GBS), leading to production of inflammatory mediators. We hypothesized that genetic deletion of G(i) proteins would alter cytokine and chemokine production induced by LPS, SA and GBS stimulation. LPS-induced, heat-killed SA-induced and heat-killed GBS-induced cytokine and chemokine production in peritoneal macrophages from wild-type (WT), Galpha(i2) (-/-) or Galpha(i1/3) (-/-) mice were investigated. LPS induced production of tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), IL-10 and interferon-gamma-inducible protein-10 (IP-10); SA induced TNF-alpha, and IL-1beta production; and GBS induced TNF-alpha, IL-6, IL-1beta, macrophage inflammatory protein-1alpha (MIP-1alpha) and keratinocyte chemoattract (KC) production were all decreased (P < 0.05) in Galpha(i2) (-/-) or Galpha(i1/3) (-/-) mice compared with WT mice. In contrast to the role of G(i) proteins as a positive regulator of mediators, LPS-induced production of MIP-1alpha and granulocyte-macrophage colony-stimulating factor (GM-CSF) were increased in macrophages from Galpha(i1/3) (-/-) mice, and SA-induced MIP-1alpha production was increased in both groups of Galpha(i) protein-depleted mice. LPS-induced production of KC and IL-1beta, SA-induced production of GM-CSF, KC and IP-10, and GBS-induced production of IL-10, GM-CSF and IP-10 were unchanged in macrophages from Galpha(i2) (-/-) or Galpha(i1/3) (-/-) mice compared with WT mice. These data suggest that G(i2) and G(i1/3) proteins are both involved and differentially regulate murine inflammatory cytokine and chemokine production in response to both LPS and Gram-positive microbial stimuli.

Beta-arrestins 1 and 2 differentially regulate LPS-induced signaling and pro-inflammatory gene expression

Toll like receptors, the critical receptor family in innate immunity, have been shown to signal via both ERK 1/2 and transcription factor NFkappaB. beta-Arrestins 1 and 2 have recently been implicated in modulation of NFkappaB signaling and ERK 1/2 activation. Using a number of approaches: mouse embryonic fibroblasts (MEF) from wild-type (WT), beta-arrestins knockouts (KO), beta-arrestins 1 and 2 double KO, and MEFs with reconstituted WT beta-arrestins in the double KO cells, RNA interference (siRNA) specific knockdown of beta-arrestins, and overexpression of WT beta-arrestins, it was demonstrated that beta-arrestin 2 positively regulates LPS-induced ERK 1/2 activation and both beta-arrestins 1 and 2 negatively regulate LPS-induced NFkappaB activation. Also beta-arrestin 2 positively regulate LPS-induced IL-6 production and both beta-arrestins 1 and 2 positively regulate LPS-induced IL-8 production. The specific ERK1/2 inhibitor PD98059 significantly decreased LPS-induced IL-6 and IL-8 production suggesting that IL-6 and IL-8 production is, in part, mediated by ERK 1/2 activation. Over expression of wild type beta-arrestins 1 and 2 had no effect on LPS-induced ERK1/2 activation and LPS-induced IL-8 production suggesting that endogenous beta-arrestins 1 and 2 are sufficient to mediate maximum ERK 1/2 activity and IL-8 production. beta-Arrestins thus not only negatively regulate LPS-induced NFkappaB activation but also positively regulate ERK 1/2 activation and specific pro-inflammatory gene expression. Understanding the role of beta-arrestins in regulation of TLR signaling pathways may provide novel insights into control mechanisms for inflammatory gene expression.