Regulation of Natural Killer Cell TGF-β and AhR Signaling Pathways Via the Intestinal Microbiota is Critical for Host Defense Against Alcohol-Associated Bacterial Pneumonia

Alcohol use is an independent risk factor for the development of bacterial pneumonia due, in part, to impaired mucus-facilitated clearance, macrophage phagocytosis, and recruitment of neutrophils. Alcohol consumption is also known to reduce peripheral natural killer (NK) cell numbers and compromises NK cell cytolytic activity, especially NK cells with a mature phenotype. However, the role of innate lymphocytes, such as NK cells during host defense against alcohol-associated bacterial pneumonia is essentially unknown. We have previously shown that indole supplementation mitigates increases in pulmonary bacterial burden and improves pulmonary NK cell recruitment in alcohol-fed mice, which were dependent of aryl hydrocarbon receptor (AhR) signaling. Employing a binge-on-chronic alcohol-feeding model we sought to define the role and interaction of indole and NK cells during pulmonary host defense against alcohol-associated pneumonia. We demonstrate that alcohol dysregulates NK cell effector function and pulmonary recruitment via alterations in two key signaling pathways. We found that alcohol increases transforming growth factor beta (TGF-β) signaling, while suppressing AhR signaling. We further demonstrated that NK cells isolated from alcohol-fed mice have a reduced ability to kill Klebsiella pneumoniae. NK cell migratory capacity to chemokines was also significantly altered by alcohol, as NK cells isolated from alcohol-fed mice exhibited preferential migration in response to CXCR3 chemokines but exhibited reduced migration in response to CCR2, CXCR4, and CX3CR1 chemokines. Together this data suggests that alcohol disrupts NK cell specific TGF-β and AhR signaling pathways leading to decreased pulmonary recruitment and cytolytic activity thereby increasing susceptibility to alcohol-associated bacterial pneumonia.

Modeling of an immune response: Queuing network analysis of the impact of zinc and cadmium on macrophage activation

Chronic obstructive pulmonary disease is characterized by progressive, irreversible airflow obstruction resulting from an abnormal inflammatory response to noxious gases and particles. Alveolar macrophages rely on the transcription factors, nuclear factor κB and mitogen-activated protein kinase, among others, to facilitate the production of inflammatory mediators designed to help rid the lung of foreign pathogens and noxious stimuli. Building a kinetic model using queuing networks, provides a quantitative approach incorporating an initial number of individual molecules along with rates of the reactions in any given pathway. Accordingly, this model has been shown useful to model cell behavior including signal transduction, transcription, and metabolic pathways. The aim of this study was to determine whether a queuing theory model that involves lipopolysaccharide-mediated macrophage activation in tandem with changes in intracellular Cd and zinc (Zn) content or a lack thereof, would be useful to predict their impact on immune activation. We then validate our model with biologic cytokine output from human macrophages relative to the timing of innate immune activation. We believe that our results further prove the validity of the queuing theory approach to model intracellular molecular signaling and postulate that it can be useful to predict additional cell signaling pathways and the corresponding biological outcomes.

Implementation of a prioritized scoring tool to improve time to pharmacist intervention

PURPOSE

The implementation of a prioritized scoring tool to improve time to pharmacist intervention is described.

SUMMARY

At the Ohio State University Wexner Medical Center, pharmacists are accepted providers of therapeutic drug monitoring of vancomycin and aminoglycosides. At the onset of this initiative and despite the implementation of an integrated electronic medical record (EMR), management of pharmacokinetically monitored medications was conducted using a paper monitoring form. The potential for transcription errors during this process provided an opportunity for improvement. For these reasons, the department of pharmacy focused its initial efforts for a patient scoring system on the pharmacokinetics scoring module. Adjustment of associated medications based on pharmacokinetic values was a core function of pharmacists of the institution and was expected to be conducted without fail. Vancomycin was used as the index surrogate pharmacokinetically monitored medication within the module for testing and validation because of the clear expectations and standardized resources available to pharmacists to complete the task. The pharmacokinetics scoring module was designed specifically for the function of dosing management, searching throughout the EMR and concisely displaying the information a pharmacist needs to make a clinical decision. Importantly, integration of the scoring module reduced the time to intervention from hours to minutes. The median time to intervention was reduced to within a clinical working shift (8 hours) with the scoring module versus 24 hours or longer with the paper monitoring system.

CONCLUSION

The implementation of an internally developed pharmacokinetics scoring module built into the EMR substantially reduced the time to clinical intervention for pharmacokinetic monitoring of vancomycin drug levels.

Accumulation of metals in GOLD4 COPD lungs is associated with decreased CFTR levels

BACKGROUND

The Cystic Fibrosis Transmembrane conductance Regulator (CFTR) is a chloride channel that primarily resides in airway epithelial cells. Decreased CFTR expression and/or function lead to impaired airway surface liquid (ASL) volume homeostasis, resulting in accumulation of mucus, reduced clearance of bacteria, and chronic infection and inflammation.

METHODS

Expression of CFTR and the cigarette smoke metal content were assessed in lung samples of controls and COPD patients with established GOLD stage 4. CFTR protein and mRNA were quantified by immunohistochemistry and quantitative RT-PCR, respectively. Metals present in lung samples were quantified by ICP-AES. The effect of cigarette smoke on down-regulation of CFTR expression and function was assessed using primary human airway epithelial cells. The role of leading metal(s) found in lung samples of GOLD 4 COPD patients involved in the alteration of CFTR was confirmed by exposing human bronchial epithelial cells 16HBE14o- to metal-depleted cigarette smoke extracts.

RESULTS

We found that CFTR expression is reduced in the lungs of GOLD 4 COPD patients, especially in bronchial epithelial cells. Assessment of metals present in lung samples revealed that cadmium and manganese were significantly higher in GOLD 4 COPD patients when compared to control smokers (GOLD 0). Primary human airway epithelial cells exposed to cigarette smoke resulted in decreased expression of CFTR protein and reduced airway surface liquid height. 16HBE14o-cells exposed to cigarette smoke also exhibited reduced levels of CFTR protein and mRNA. Removal and/or addition of metals to cigarette smoke extracts before exposure established their role in decrease of CFTR in airway epithelial cells.

CONCLUSIONS

CFTR expression is reduced in the lungs of patients with severe COPD. This effect is associated with the accumulation of cadmium and manganese suggesting a role for these metals in the pathogenesis of COPD.

Pro-inflammatory response of human bronchial epithelial cells following Burkholderia cenocepacia infection: focus on IL-1β. (P1265)

Burkholderia cenocepacia is the causative agent of the fatal lung disease, Cepacia syndrome. Epithelial cells are the first cells challenged in airway infections, yet, their pro-inflammatory response to B. cenocepacia remains under investigated. Here, we aimed to determine pro-inflammatory mechanisms initiated by airway epithelial cells following B. cenocepacia infection. We first examined signaling pathways activated post B.cenocepacia infection, and found that phosphorylation of Erk, Akt, Iκk, and NF-κB occurred. Cytokine profiles showed that while epithelial cells secreted TNFα, IL-6, and IL-8, they did not secrete IL-1β. Strikingly, qRT-PCR showed significantly elevated mRNA levels of IL1b. Examination of IL-1β within cell lysates revealed pro-IL-1β was present at significant amounts, but the mature form failed to be secreted. This inability to secrete IL-1β was not specific to B. cenocepacia, as LPS stimulation showed similiar results. Caspase-1 is required for pro-IL-1β processing and mature IL-1β release. Interestingly, we found that caspase-1 was expressed at minimal levels in both mRNA and protein forms within epithelial cells. Transfection experiments showed that restoration of caspase-1 expression in epithelial cells permits IL-1β secretion. Our data show, for the first time, that deficiency of fundamental inflammasome components, particularly caspase-1, may be responsible for the lack of IL-1β secretion by infected epithelial cells.

Cadmium suppresses IL-1β production and release in monocytes. (P3010)

Tobacco smoke is the primary cause of chronic obstructive pulmonary disease (COPD) in the U.S. Immune dysfunction in the lung of chronic smokers increases the risk of respiratory infections. IL-1β is a vital cytokine in host defense and its expression is decreased in the lungs of these patients. Cadmium (Cd) is abundant in cigarette smoke and a major contributor to smoking-related lung disease. The purpose of this investigation is to determine whether Cd suppresses IL-1β in monocytes. THP-1 cells were differentiated into macrophages using PMA and then treated overnight with Cd, followed by combined LPS and ATP stimulation. Primary human monocytes were isolated from blood using CD14+ positive selection and subject to similar exposures. Analysis of THP-1 and monocyte cultures revealed that Cd suppresses IL-1β release following stimulation with LPS and ATP. Additionally, there was a decrease in IL-1β mRNA in Cd-treated LPS stimulated macrophages. We observed a decrease in phospho-p65 translocation into the nucleus of Cd-treated macrophages after LPS stimulation. Consistent with this, using a cell-free system, we observed that Cd inhibits IKKβ kinase activity (IC50 of ~100 nM). From these studies we conclude that Cd acts as an inhibitor of the canonical NF-κB pathway and inhibits IL-1β production. Accordingly, Cd may play a critical role in COPD pathogenesis by impairing monocyte immune function.

Allelic mRNA expression imbalance in C-type lectins reveals a frequent regulatory SNP in the human surfactant protein A (SP-A) gene

Genetic variation in C-type lectins influences infectious disease susceptibility but remains poorly understood. We employed allelic mRNA expression imbalance (AEI) technology for SP-A1, SP-A2, SP-D, DC-SIGN, MRC1, and Dectin-1, expressed in human macrophages and/or lung tissues. Frequent AEI, an indicator of regulatory polymorphisms, was observed in SP-A2, SP-D, and DC-SIGN. AEI was measured for SP-A2 in 38 lung tissues using four marker SNPs and was confirmed by next generation sequencing of one lung RNA sample. Genomic DNA at the SP-A2 DNA locus was sequenced by Ion Torrent technology in 16 samples. Correlation analysis of genotypes with AEI identified a haplotype block, and, specifically, the intronic SNP rs1650232 (30% MAF); the only variant consistently associated with an approximately two-fold change in mRNA allelic expression. Previously shown to alter a NAGNAG splice acceptor site with likely effects on SP-A2 expression, rs1650232 generates an alternative splice variant with three additional bases at the start of exon 3. Validated as a regulatory variant, rs1650232 is in partial LD with known SP-A2 marker SNPs previously associated with risk for respiratory diseases including tuberculosis. Applying functional DNA variants in clinical association studies, rather than marker SNPs, will advance our understanding of genetic susceptibility to infectious diseases.

The zinc transporter SLC39A8 is a novel negative feedback regulator of the NF-κB pathway and innate immune activation (116.33)

Zinc is an essential micronutrient required for proper immune function. We previously reported that zinc deficiency increases inflammation and mortality in response to polymicrobial sepsis. Here we report that a specific zinc transporter, SLC39A8 (ZIP8), is a transcriptional target of NF-κB and functions as a negative regulator of NF-κB. Initially we observed that TNFα or LPS inducesSLC39A8 expression in human monocytes, macrophages and lung epithelial cells, leading to an increase in intracellular zinc. We then identified a functional NF-κB binding site in the promoter region that triggers ZIP8 expression. Silencing of ZIP8 expression significantly decreased intracellular accumulation of zinc and increased the inflammatory response, as determined by increased cytokine production and phosphorylation of IκBα, P65, ERK and Akt. We further revealed that zinc directly inhibits IKKβ in a ZIP8-dependent manner. In mice, endotoxin or cecal ligation and puncture resulted in increased ZIP8 expression and zinc uptake in circulating monocytes and lung tissue, contributing to hypozincemia. Consistent with these observations, mouse embryonic fibroblasts obtained from Slc39a8 hypomorphic mice were more responsive to TNFα and IL-1β compared to wild-type cells, confirming the function of ZIP8 as a negative regulator of NF-κB and innate immune activation. Taken together, our findings identify a novel inducible inhibitory feedback pathway for NF-κB and the pro-inflammatory response.

Sepsis: links between pathogen sensing and organ damage

The host's inflammatory response to sepsis can be divided into two phases, the initial detection and response to the pathogen initiated by the innate immune response, and the persistent inflammatory state characterized by multiple organ dysfunction syndrome (MODS). New therapies aimed at pathogen recognition receptors (PRRs) particularly the TLRs and the NOD-like receptors offer hope to suppress the initial inflammatory response in early sepsis and to bolster this response in late sepsis. The persistence of MODS after the initial inflammatory surge can also be a determining factor to host survival. MODS is due to the cellular damage and death induced by sepsis. The mechanism of this cell death depends in part upon mitochondrial dysfunction. Damaged mitochondria have increased membrane permeability prompting their autophagic removal if few mitochondria are involved but apoptotic cell death may occur if the mitochondrial losses are more extensive. In addition. severe loss of mitochondria results in low cell energy stores, necrotic cell death, and increased inflammation driven by the release of cell components such as HMGB1. Therapies, which aim at improving cellular energy reserves such as the promotion of mitochondrial biogenesis by insulin, may have a role in future sepsis therapies. Finally, both the inflammatory responses and the susceptibility to organ failure may be modulated by nutritional status and micronutrients, such as zinc, Therapies aimed at micronutrient repletion may further augment approaches targeting PRR function and mitochondrial viability.

Pharm. D. pathways to biomedical research: the National Institutes of Health special conference on pharmacy research

To address the shortage of research-trained pharmaceutical scientists (or doctor of pharmacy [Pharm.D.] scientists), a 2-day pharmacy research conference titled "Pharm.D. Pathways to Biomedical Research" was convened on December 13-14, 2006, at the National Institutes of Health (NIH) campus (Bethesda, MD). The workshop included invited speakers and participants from academia, industry, and government. Forty-two pharmacy schools were represented, including deans and clinical pharmaceutical scientists with current NIH funding. In addition, several pharmacy professional organizations were represented--American Association of Colleges of Pharmacy, American College of Clinical Pharmacy, American Society of Health-System Pharmacists, and the Accreditation Council on Pharmaceutical Education. The workshop was divided into three sessions followed by breakout discussion groups: the first session focused on presentations by leading pharmaceutical scientists who described their path to success; the second session examined the NIH grant system, particularly as it relates to training opportunities in biomedical research and funding mechanisms; and the third session addressed biomedical research education and training from the perspective of scientific societies and academia. We summarize the discussions and findings from the workshop and highlight some important considerations for the future of research in the pharmacy community. This report also puts forth recommendations for educating future pharmaceutical scientists.

Correlation of HIV-1 Detection and Histology in AIDS-Associated Emphysema

HIV-seropositive individuals are at an increased risk for an accelerated form of emphysema. The purpose of this study was to determine the distribution of HIV-1 RNA in lung tissues and correlate this with the histologic findings and expression of matrix metalloproteases (MMPs). Reverse transcriptase (RT) in situ PCR analysis was performed on 11 AIDS lung autopsy specimens which showed varying degrees of emphysematous changes. In each lung, HIV-1 RNA was detected. In areas of histologically normal lung, very rare HIV-1-infected cells were evident. In contrast, many HIV-1-infected cells were noted in areas of emphysema. HIV-1 gag RNA was evident primarily in macrophages; infected pneumocytes were also seen. Similarly, MMP mRNA and protein, primarily MMP-9, localized to the areas of emphysema. Colabeling experiments documented that MMP expression was found primarily in cells that were HIV-1 negative and adjacent to HIV-1-infected macrophages. These results suggest that AIDS-related emphysema may be due, in part, to direct infection by HIV-1 of, primarily, alveolar macrophages, and concomitant up-regulation of MMP expression in the neighboring, noninfected cells.

Gene expression following direct injection of DNA into liver

The liver is an attractive target tissue for gene therapy. Current approaches for hepatic gene delivery include retroviral and adenoviral vectors, liposome/DNA, and peptide/DNA complexes. This study describes a technique for direct injection of DNA into liver that led to significant gene expression. Gene expression was characterized in both rats and cats following injection of plasmid DNA encoding several different proteins. Luciferase activity was measured after injection of plasmid DNA encoding the luciferase gene (pCMVL), beta-galactosidase (beta-Gal) activity was evaluated in situ using plasmid DNA encoding Lac Z (pCMV beta), and serum concentration of secreted human alpha-1-antitrypsin was measured following injection of plasmid DNA encoding this protein (pRC/CMV-sHAT). Several variables, including injection technique, DNA dose, and DNA diluent, were investigated. Direct injection of pCMVL resulted in maximal luciferase expression at 24-48 hr. beta-Gal staining demonstrated that the majority of transfected hepatocytes were located near the injection site. Significant concentrations of human alpha-1-antitrypsin were detected in the serum of animals injected with pRC/CMV-sHAT. These findings demonstrate the general principle that direct injection of plasmid DNA into liver can lead to significant gene expression.