Joan Reibman

Colchicine alters the quantitative and qualitative display of selectins on endothelial cells and neutrophils.

Since colchicine-sensitive microtubules regulate the expression and topography of surface glycoproteins on a variety of cells, we sought evidence that colchicine interferes with neutrophil-endothelial interactions by altering the number and/or distribution of selectins on endothelial cells and neutrophils. Extremely low, prophylactic, concentrations of colchicine (IC50 = 3 nM) eliminated the E-selectin-mediated increment in endothelial adhesiveness for neutrophils in response to IL-1 (P < 0.001) or TNF alpha (P < 0.001) by changing the distribution, but not the number, of E-selectin molecules on the surface of the endothelial cells. Colchicine inhibited stimulated endothelial adhesiveness via its effects on microtubules since vinblastine, an agent which perturbs microtubule function by other mechanisms, diminished adhesiveness whereas the photoinactivated colchicine derivative gamma-lumicolchicine was inactive. Colchicine had no effect on cell viability. At higher, therapeutic, concentrations colchicine (IC50 = 300 nM, P < 0.001) also diminished the expression of L-selectin on the surface of neutrophils (but not lymphocytes) without affecting expression of the beta 2-integrin CD11b/CD18. In confirmation, L-selectin expression was strikingly reduced (relative to CD11b/CD18 expression) on neutrophils from two individuals who had ingested therapeutic doses of colchicine. These results suggest that colchicine may exert its prophylactic effects on cytokine-provoked inflammation by diminishing the qualitative expression of E-selectin on endothelium, and its therapeutic effects by diminishing the quantitative expression of L-selectin on neutrophils.

Does Helicobacter pylori protect against asthma and allergy

The microbes that persistently colonise their vertebrate hosts are not accidental.1 Although highly numerous and diverse, there is specificity by site and substantial conservation between individuals. The genus Helicobacter includes spiral, highly motile, urease-positive, Gram-negative bacteria that colonise the stomach in many mammals. Each mammal has one or more dominant Helicobacter species and they are highly, if not exclusively, host species-specific.2 Such observations are consistent with the hypothesis that when ancestral mammals diverged from reptiles about 150 million years ago, they contained ancestral helicobacters, which then diverged as their hosts changed. According to this hypothesis, helicobacters represent ancestral biota (flora) in the mammalian stomach. The human-adapted strain is H pylori ,3 which has not been reproducibly observed in any animals other than humans and other primates.3 Although we can not reliably estimate how long H pylori has been in the human stomach, its ancestors may have been present when our humanoid ancestors diverged from other primates about four million years ago. Consistent with this view are results from phylogeographic studies; strong and consistent evidence indicates that our ancestors already were carrying gastric H pylori when a group that ultimately populated much of the world last left Africa, more than 58 000 years ago.4 In any case, H pylori has been colonising the stomach of humans since at least Paleolithic times. In this paper, we examine the evidence concerning the relationship of this ancient member of the human microbiota, and particularly its absence, with the recent and on-going epidemic of asthma and related allergic disorders. We discuss the possibility that gastric H pylori colonisation protects against these disorders and that its disappearance has fuelled their rise. H pylori is acquired, and may be detected, in early childhood usually after the first year of life.5 Transmission is …

Asthma Is Inversely Associated with Helicobacter pylori Status in an Urban Population

Background Microbial exposures have been suggested to confer protection from allergic disorders and reduced exposures to gastrointestinal microbiota have been proposed as an explanation for the increase in asthma prevalence. Since the general prevalence of Helicobacter pylori has been decreasing, we hypothesized that H. pylori serostatus would be inversely related to the presence of asthma. Methods Adults were recruited to participate in the New York University (NYU)/Bellevue Asthma Registry in New York City. Adult asthma cases (N = 318) and controls (N = 208) were identified and serum IgG antibodies to H. pylori whole cell antigens or the immunodominant CagA antigen were measured. Results As expected, the asthma cases and controls differed with respect to atopy and lung function. Seropositivity to H. pylori or CagA antigen was present in 47.1% of the total case and control study population. Asthma was inversely associated with CagA seropositivity (OR = 0.57, 95% CI = 0.36–0.89). Median age of onset of asthma (doctors diagnosis) was older (21 years) among individuals with CagA+ strains than among H. pylori- individuals (11 years) (p = 0.006). Conclusion These data are consistent with the hypothesis that colonization with CagA+ H. pylori strains is inversely associated with asthma and is associated with an older age of asthma onset in an urban population. The data suggest H. pylori as a marker for protection. Trial Registration ClinicalTrials.gov NCT00212537

Diesel Exhaust Particle-Exposed Human Bronchial Epithelial Cells Induce Dendritic Cell Maturation

Increased exposure to air pollutants such as diesel exhaust particles (DEP) has been proposed as one mechanism to explain the rise in allergic disorders. However, the immunologic mechanisms by which DEP enhance allergic sensitization and asthma remain unclear. We hypothesized that DEP act as an adjuvant for immature dendritic cell (DC) maturation via its effect on airway epithelial cell-derived microenvironment for DC. Immature monocyte-derived DC (iMDDC) failed to undergo phenotypic (CD80, CD83, CD86) or functional (T cell activation) maturation in response to exposure to DEP (0.001–100 μg/ml). In contrast, primary cultures of human bronchial epithelial cells (HBEC) treated with DEP induced iMDDC phenotypic maturation (2.6 ± 0.1-fold increase in CD83 expression, n = 4, p < 0.05) and functional maturation (2.6 ± 0.2-fold increase in T cell activation, n = 4, p < 0.05). Functional maturation of iMDDC was induced by conditioned medium derived from DEP-treated HBEC, and was inhibited in cultures with DEP-treated HBEC and blocking Abs against GM-CSF, or GM-CSF-targeted small interfering RNA. These data suggest that DEP induce Ag-independent DC maturation via epithelial cell-DC interactions mediated by HBEC-derived GM-CSF. Although additional signals may be required for polarization of DC, these data suggest a novel mechanism by which environmental pollutants alter airway immune responses.

The World Trade Center Residents’ Respiratory Health Study: New-Onset Respiratory Symptoms and Pulmonary Function

The destruction of the World Trade Center (WTC) on 11 September 2001 in New York City resulted in the massive release of pulverized dust and combustion products. The dust and smoke settled in the surrounding area, which encompassed a large residential community. We hypothesized that previously normal residents in the community surrounding the former WTC would have an increased incidence of persistent respiratory symptoms and abnormalities in screening spirometry. A hybrid cross-sectional and retrospective cohort study using a symptom-based questionnaire and onsite screening spirometry in residents in an exposed area and in a control area was performed 12 ± 4 months after the collapse. Surveys were analyzed from 2,812 residents. New-onset respiratory symptoms were described by 55.8% of residents in the exposed area, compared with 20.1% in the control area after the event. Persistent new-onset symptoms were identified in 26.4 versus 7.5% of residents in the exposed area versus control area, respectively. No differences in screening spirometry between the groups were detected. A small pilot study suggested the possibility of an increase in bronchial hyperresponsiveness in exposed participants with persistent symptoms. The data demonstrate an increased rate of new-onset and persistent respiratory health effects in residents near the former WTC compared with a control population.

Diesel exhaust particle-exposed human bronchial epithelial cells induce dendritic cell maturation and polarization via thymic stromal lymphopoietin.

Human exposure to air pollutants, including ambient particulate matter, has been proposed as a mechanism for the rise in allergic disorders. Diesel exhaust particles, a major component of ambient particulate matter, induce sensitization to neoallergens, but the mechanisms by which sensitization occur remain unclear. We show that diesel exhaust particles upregulate thymic stromal lymphopoietin in human bronchial epithelial cells in an oxidant-dependent manner. Thymic stromal lymphopoietin induced by diesel exhaust particles was associated with maturation of myeloid dendritic cells, which was blocked by anti-thymic stromal lymphopoietin antibodies or silencing epithelial cell-derived thymic stromal lymphopoietin. Dendritic cells exposed to diesel exhaust particle-treated human bronchial epithelial cells induced Th2 polarization in a thymic stromal lymphopoietin-dependent manner. These findings provide new insight into the mechanisms by which diesel exhaust particles modify human lung mucosal immunity.

Diesel Exhaust Particle-Treated Human Bronchial Epithelial Cells Upregulate Jagged-1 and OX40 Ligand in Myeloid Dendritic Cells via Thymic Stromal Lymphopoietin

Ambient particulate matter, including diesel exhaust particles (DEP), promotes the development of allergic disorders. DEP increase oxidative stress and influence human bronchial epithelial cell (HBEC)–dendritic cell interactions via cytokines, including thymic stromal lymphopoietin (TSLP). Upregulation of TSLP results in Th2 responses. Using primary culture HBEC and human myeloid dendritic cell (mDC) cocultures, we show in this study that DEP upregulation of Th2 responses occurred via HBEC-dependent mechanisms that resulted from oxidative stress. Moreover, DEP-treated HBEC and ambient particulate matter-treated HBEC upregulated OX40 ligand (OX40L) and the Notch ligand Jagged-1 mRNA and expression on mDC. Upregulation of OX40L as well as Jagged-1 on mDC required HBEC and did not occur in the presence of N-acetylcysteine. Furthermore, OX40L and Jagged-1 upregulation was inhibited when HBEC expression of TSLP was silenced. Thus, DEP treatment of HBEC targeted two distinct pathways in mDC that were downstream of TSLP expression. Upregulation of OX40L and Jagged-1 by mDC resulted in mDC-driven Th2 responses. These studies expand our understanding of the mechanism by which ambient pollutants alter mucosal immunity and promote disorders such as asthma.

MicroRNA-375 Regulation of Thymic Stromal Lymphopoietin by Diesel Exhaust Particles and Ambient Particulate Matter in Human Bronchial Epithelial Cells

Air pollution contributes to acute exacerbations of asthma and the development of asthma in children and adults. Airway epithelial cells interface innate and adaptive immune responses, and have been proposed to regulate much of the response to pollutants. Thymic stromal lymphopoietin (TSLP) is a pivotal cytokine linking innate and Th2 adaptive immune disorders, and is upregulated by environmental pollutants, including ambient particulate matter (PM) and diesel exhaust particles (DEP). We show that DEP and ambient fine PM upregulate TSLP mRNA and human microRNA (hsa-miR)-375 in primary human bronchial epithelial cells (pHBEC). Moreover, transfection of pHBEC with anti–hsa-miR-375 reduced TSLP mRNA in DEP but not TNF-α–treated cells. In silico pathway evaluation suggested the aryl hydrocarbon receptor (AhR) as one possible target of miR-375. DEP and ambient fine PM (3 μg/cm2) downregulated AhR mRNA. Transfection of mimic-hsa-miR-375 resulted in a small downregulation of AhR mRNA compared with resting AhR mRNA. AhR mRNA was increased in pHBEC treated with DEP after transfection with anti–hsa-miR-375. Our data show that two pollutants, DEP and ambient PM, upregulate TSLP in human bronchial epithelial cells by a mechanism that includes hsa-miR-375 with complex regulatory effects on AhR mRNA. The absence of this pathway in TNF-α–treated cells suggests multiple regulatory pathways for TSLP expression in these cells.

Case–Control Study of Lung Function in World Trade Center Health Registry Area Residents and Workers

RATIONALE Residents and area workers who inhaled dust and fumes from the World Trade Center disaster reported lower respiratory symptoms in two World Trade Center Health Registry surveys (2003-2004 and 2006-2007), but lung function data were lacking. OBJECTIVES To examine the relationship between persistent respiratory symptoms and pulmonary function in a nested case-control study of exposed adult residents and area workers 7-8 years after September 11, 2001. METHODS Registrants reporting post September 11th onset of a lower respiratory symptom in the first survey and the same symptom in the second survey were solicited as potential cases. Registrants without lower respiratory symptoms in either Registry survey were solicited as potential control subjects. Final case-control status was determined by lower respiratory symptoms at a third interview (the study), when spirometry and impulse oscillometry were also performed. MEASUREMENTS AND MAIN RESULTS We identified 180 cases and 473 control subjects. Cases were more likely than control subjects to have abnormal spirometry (19% vs. 11%; P < 0.05), and impulse oscillometry measurements of elevated airway resistance (R5; 68% vs. 27%; P < 0.0001) and frequency dependence of resistance (R₅₋₂₀; 36% vs. 7%; P < 0.0001). When spirometry was normal, cases were more likely than control subjects to have elevated R₅ and R₅₋₂₀ (62% vs. 25% and 27% vs. 6%, respectively; both P < 0.0001). Associations between symptoms and oscillometry held when factors significant in bivariate comparisons (body mass index, spirometry, and exposures) were analyzed using logistic regression. CONCLUSIONS This study links persistent respiratory symptoms and oscillometric abnormalities in World Trade Center-exposed residents and area workers. Elevated R₅ and R₅₋₂₀ in cases despite normal spirometry suggested distal airway dysfunction as a mechanism for symptoms.

Regulation of expression of granulocyte-macrophage colony-stimulating factor in human bronchial epithelial cells: roles of protein kinase C and mitogen-activated protein kinases.

GM-CSF has a major role in the immune and inflammatory milieu of the airway. Airway epithelial cells (AEC) are among the first targets of environmental stimuli and local cytokines, in response to which they can produce GM-CSF. The regulation of GM-CSF is only minimally understood in AEC. We hypothesized that GM-CSF expression in AEC would result from activation of protein kinase C (PKC) and subsequent activation of the extracellular signal-regulated kinase (MAPKerk1/2) pathway, so we investigated signal transduction pathways in human primary culture bronchial epithelial cells (HBECs). TNF-α, IL-1β, and PMA induced the release of GM-CSF in HBECs. The robust response to PMA was not detected in SV40 adenovirus-transformed normal human bronchial epithelial cells (BEAS-2B). PMA and TNF-α stimulation of GM-CSF required activation of PKC (inhibition by staurosporine and bisindolylmaleimide I). GM-CSF expression was up-regulated by a nonphorbol PKC activator, but not by an inactive PMA analogue. PMA-induced GM-CSF production in HBECs did not require a Ca2+ ionophore and was not inhibited by cyclosporin A. Activation of MAPKerk1/2 via PKC was associated with and was required for GM-CSF production induced by PMA and TNF-α. The data demonstrate regulation of GM-CSF in HBECs by PKC pathways converging on the MAPKerk1/2 pathway and further define cell-specific regulation critical for local airway responses.