Kamala D. Patel

Platelet TLR4 activates neutrophil extracellular traps to ensnare bacteria in septic blood.

It has been known for many years that neutrophils and platelets participate in the pathogenesis of severe sepsis, but the inter-relationship between these players is completely unknown. We report several cellular events that led to enhanced trapping of bacteria in blood vessels: platelet TLR4 detected TLR4 ligands in blood and induced platelet binding to adherent neutrophils. This led to robust neutrophil activation and formation of neutrophil extracellular traps (NETs). Plasma from severely septic humans also induced TLR4-dependent platelet-neutrophil interactions, leading to the production of NETs. The NETs retained their integrity under flow conditions and ensnared bacteria within the vasculature. The entire event occurred primarily in the liver sinusoids and pulmonary capillaries, where NETs have the greatest capacity for bacterial trapping. We propose that platelet TLR4 is a threshold switch for this new bacterial trapping mechanism in severe sepsis.

Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress, and immune parameters in breast and prostate cancer outpatients.

Objectives: This study investigated the relationships between a mindfulness‐based stress reduction meditation program for early stage breast and prostate cancer patients and quality of life, mood states, stress symptoms, lymphocyte counts, and cytokine production. Methods: Forty‐nine patients with breast cancer and 10 with prostate cancer participated in an 8‐week MBSR program that incorporated relaxation, meditation, gentle yoga, and daily home practice. Demographic and health behavior variables, quality of life (EORTC QLQ C‐30), mood (POMS), stress (SOSI), and counts of NK, NKT, B, T total, T helper, and T cytotoxic cells, as well as NK and T cell production of TNF, IFN‐&ggr;, IL‐4, and IL‐10 were assessed pre‐ and postintervention. Results: Fifty‐nine and 42 patients were assessed pre‐ and postintervention, respectively. Significant improvements were seen in overall quality of life, symptoms of stress, and sleep quality. Although there were no significant changes in the overall number of lymphocytes or cell subsets, T cell production of IL‐4 increased and IFN‐&ggr; decreased, whereas NK cell production of IL‐10 decreased. These results are consistent with a shift in immune profile from one associated with depressive symptoms to a more normal profile. Conclusions: MBSR participation was associated with enhanced quality of life and decreased stress symptoms in breast and prostate cancer patients. This study is also the first to show changes in cancer‐related cytokine production associated with program participation.

One year pre-post intervention follow-up of psychological, immune, endocrine and blood pressure outcomes of mindfulness-based stress reduction (MBSR) in breast and prostate cancer outpatients.

OBJECTIVES This study investigated the ongoing effects of participation in a mindfulness-based stress reduction (MBSR) program on quality of life (QL), symptoms of stress, mood and endocrine, immune and autonomic parameters in early stage breast and prostate cancer patients. METHODS Forty-nine patients with breast cancer and 10 with prostate cancer enrolled in an eight-week MBSR program that incorporated relaxation, meditation, gentle yoga and daily home practice. Demographic and health behaviors, QL, mood, stress symptoms, salivary cortisol levels, immune cell counts, intracellular cytokine production, blood pressure (BP) and heart rate (HR) were assessed pre- and post-intervention, and at 6- and 12-month follow-up. RESULTS Fifty-nine, 51, 47 and 41 patients were assessed pre- and post-intervention and at 6- and 12-month follow-up, respectively, although not all participants provided data on all outcomes at each time point. Linear mixed modeling showed significant improvements in overall symptoms of stress which were maintained over the follow-up period. Cortisol levels decreased systematically over the course of the follow-up. Immune patterns over the year supported a continued reduction in Th1 (pro-inflammatory) cytokines. Systolic blood pressure (SBP) decreased from pre- to post-intervention and HR was positively associated with self-reported symptoms of stress. CONCLUSIONS MBSR program participation was associated with enhanced quality of life and decreased stress symptoms, altered cortisol and immune patterns consistent with less stress and mood disturbance, and decreased blood pressure. These pilot data represent a preliminary investigation of the longer-term relationships between MBSR program participation and a range of potentially important biomarkers.

Neutrophils use both shared and distinct mechanisms to adhere to selectins under static and flow conditions.

Both P-selectin glycoprotein ligand-1 (PSGL-1) and L-selectin are localized on the microvilli of neutrophils and have been implicated in the attachment of neutrophils to P-selectin or E-selectin. We directly compared the attachment and rolling of neutrophils on P-selectin and E-selectin under flow, with emphasis on the functions of PSGL-1 and L-selectin. Flowing neutrophils attached more avidly and rolled at lower velocities on P-selectin than on E-selectin at matched densities. Studies with purified molecules indicated that P-selectin and E-selectin bound to a related site on PSGL-1 that overlapped the epitope for the anti-PSGL-1 mAb PL1. E-selectin bound with lower affinity than P-selectin to this site and also bound to an additional site(s) on PSGL-1.PL1 abolished adhesion of neutrophils to P-selectin under shear or static conditions, whereas DREG-56, a mAb to L-selectin, had no effect on adhesion to P-selectin. PL1 inhibited attachment of neutrophils to E-selectin under flow but not static conditions. DREG-56 also inhibited attachment of flowing neutrophils to E-selectin, and a combination of DREG-56 and PL1 nearly eliminated attachment to E-selectin under flow. These data suggest that PSGL-1 functions cooperatively with L-selectin to mediate optimal attachment of flowing neutrophils to E-selectin but not to P-selectin. Neutrophils attach more efficiently and with greater strength to P-selectin, perhaps because of the higher affinity of P-selectin for the PL1-defined site on PSGL-1.

MATRIX METALLOPROTEINASE-2 (MMP-2) AND MMP-9 IN PULMONARY PATHOLOGY

The lung is affected by a variety of disease processes that can lead to considerable morbidity and mortality. As the lung is the only organ for respiration and gas exchange, the structural and functional integrity of the lung is of primary importance. Various pathological processes affect the extracellular matrix (ECM) of the lung in an adverse manner, causing destruction of tissue integrity followed by tissue remodeling, which together impair normal pulmonary function. Matrix metalloproteinases (MMPs) are neutral proteinases that are involved in the breakdown and remodeling of the ECM under a variety of physiological and pathological conditions. MMP-2 and MMP-9, collectively known as the gelatinases, are particularly important in the pathogenesis of inflammatory, infectious, and neoplastic diseases in many organs including the lung. This review examines the expression of MMP-2 and MMP-9 in disease of the lung and discusses the role these gelatinases may play in disease progression.

Transient Translocation of the B Cell Receptor and Src Homology 2 Domain-Containing Inositol Phosphatase to Lipid Rafts: Evidence Toward a Role in Calcium Regulation

Membrane microdomains (lipid rafts) are enriched in selected signaling molecules and may compartmentalize receptor-mediated signals. Here, we report that in primary human B lymphocytes and in Ramos B cells B cell receptor (BCR) stimulation induces rapid and transient redistribution of a subset of engaged BCRs to lipid rafts and phosphorylation of raft-associated tyrosine kinase substrates. Cholesterol sequestration disrupted the lipid rafts, preventing BCR redistribution, but did not inhibit tyrosine kinase activation or phosphorylation of mitogen-activated protein kinase/extracellular regulated kinase. However, raft disruption enhanced the release of calcium from intracellular stores, suggesting that rafts may sequester early signaling events that down-regulate calcium flux. Consistent with this, BCR stimulation induced rapid and transient translocation of the Src homology 2 domain-containing inositol phosphatase, SHIP, into lipid rafts.

The Role of Capsid–Endothelial Interactions in the Innate Immune Response to Adenovirus Vectors

Adenovirus (Ad) vectors can produce inflammatory responses at high doses. Intravenous administration of an Ad vector expressing green fluorescent protein (AdGFP) to naive mice induced a biphasic pattern of liver cytokine/chemokine gene expression over 7 days. Tumor necrosis factor alpha (TNF-alpha), macrophage inflammatory protein 2 (MIP-2), and interferon gamma-inducible protein 10 (IP-10) genes were upregulated, with two distinct peaks of mRNA expression occurring at 6 hr and 5 days. The administration of transcription-defective AdGFP particles induced the early but not the late peak of chemokine/cytokine gene expression, confirming that Ad vector-induced inflammation is capsid dependent in the early phase and transcription dependent in the late phase. To determine the role of adenoviral capsid motifs in the early phase, capsid-modified Ad vectors were employed. The intravenous administration of the RGD-deleted Ad vector AdL.PB*, the fiber mutant AdL.F*, or the double mutant AdL.F*PB* induced similar levels of cytokine/chemokine expression compared with the wild-type vector AdLuc. Kupffer cell blockade significantly reduced liver TNF-alpha, MIP-2, and IP-10 gene expression and liver inflammation after the administration of AdL.PB* or AdL.F*PB*. Fluorescence microscopy of AdLuc- and AdL.PB*-transduced liver at 1 hr revealed localization of Ad vectors to liver sinusoids in Kupffer cell-depleted mice. AdL.PB* induced less E-selectin and VCAM-1 gene expression in liver, confirming reduced endothelial activation in mice receiving RGD-deleted Ad vectors. In vitro studies of endothelial cells demonstrated reduced transduction and endothelial activation by AdL.PB* compared with AdLuc. These results demonstrate that adenovirus capsid RGD motifs are required for efficient transduction and endothelial cell activation. Altering vector tropism represents a feasible strategy to modulate the innate response to Ad vectors in nontargeted tissues.

Regulation of matrix metalloproteinase-9 release from IL-8-stimulated human neutrophils

Matrix metalloproteinase‐9 (MMP‐9) is present in the tertiary granules of neutrophils and can be released following stimulation. We examined the signaling mechanisms that regulate interleukin‐8 (IL‐8)‐mediated MMP‐9 release from neutrophils. IL‐8 activates neutrophils by interacting with two receptors: CXC chemokine receptor 1 (CXCR1) and CXCR2. Blocking CXCR1 had no effect on IL‐8‐mediated MMP‐9 release, whereas blocking CXCR2 significantly reduced MMP‐9 release. We also found that stimulating CXCR2 alone was sufficient to induce MMP‐9 release. This process was independent of changes in the intracellular calcium concentration. Src‐family kinases and protein kinase C (PKC) were involved in two mutually exclusive pathways regulating IL‐8‐mediated MMP‐9 release. Inhibition of extracellular signal‐regulated kinase (ERK)1/2 blocked IL‐8‐mediated MMP‐9 release; however, inhibition of p38 mitogen‐activated protein kinase had no effect on MMP‐9 release. We found ERK1/2 was activated downstream of PKC, but not Src‐family kinases, in this system. These data suggest that IL‐8‐induced MMP‐9 release from neutrophils is mediated through CXCR2 and involves two distinct pathways, one involving PKC and ERK1/2 and the other involving Src‐family kinases. Furthermore, our data show that the mechanisms that regulate MMP‐9 release from tertiary granules are different from those that regulate primary granule release.

Targeting endocannabinoid degradation protects against experimental colitis in mice: involvement of CB1 and CB2 receptors

The endocannabinoid (EC) system mediates protection against intestinal inflammation. In this study, we investigated the effects of blocking EC degradation or cellular reuptake in experimental colitis in mice. Mice were treated with trinitrobenzene-sulfonic acid in presence and absence of the fatty acid amide hydrolase (FAAH) blocker URB597, the EC membrane transport inhibitor VDM11, and combinations of both. Inflammation was significantly reduced in the presence of URB597, VDM11, or both as evaluated by macroscopic damage score, myeloperoxidase levels, and colon length. These effects were abolished in CB1- and CB2-receptor-gene-deficient mice. Quantitative reverse transcription polymerase chain reaction after induction of experimental colitis by different pathways showed that expression of FAAH messenger RNA (mRNA) is significantly reduced in different models of inflammation early in the expression of colitis, and these return to control levels as the disease progresses. Genomic DNA from 202 patients with Crohn’s disease (CD) and 206 healthy controls was analyzed for the C385A polymorphism in the FAAH gene to address a possible role in humans. In our groups, the C385A polymorphism was equally distributed in patients with CD and healthy controls. In conclusion, drugs targeting EC degradation offer therapeutic potential in the treatment of inflammatory bowel diseases. Furthermore, reduction of FAAH mRNA expression is involved in the pathophysiological response to colitis.

Cannabinoid CB2 receptors in the enteric nervous system modulate gastrointestinal contractility in lipopolysaccharide-treated rats

Enhanced intestinal transit due to lipopolysaccharide (LPS) is reversed by cannabinoid (CB)2 receptor agonists in vivo, but the site and mechanism of action are unknown. We have tested the hypothesis that CB2 receptors are expressed in the enteric nervous system and are activated in pathophysiological conditions. Tissues from either saline- or LPS-treated (2 h; 65 microg/kg ip) rats were processed for RT-PCR, Western blotting, and immunohistochemistry or were mounted in organ baths where electrical field stimulation was applied in the presence or absence of CB receptor agonists. Whereas the CB2 receptor agonist JWH133 did not affect the electrically evoked twitch response of the ileum under basal conditions, in the LPS-treated tissues JWH133 was able to reduce the enhanced contractile response in a concentration-dependent manner. Rat ileum expressed CB2 receptor mRNA and protein under physiological conditions, and this expression was not affected by LPS treatment. In the myenteric plexus, CB2 receptors were expressed on the majority of neurons, although not on those expressing nitric oxide synthase. LPS did not alter the distribution of CB2 receptor expression in the myenteric plexus. In vivo LPS treatment significantly increased Fos expression in both enteric glia and neurons. This enhanced expression was significantly attenuated by JWH133, whose action was reversed by the CB2 receptor antagonist AM630. Taking these facts together, we conclude that activation of CB2 receptors in the enteric nervous system of the gastrointestinal tract dampens endotoxin-induced enhanced intestinal contractility.