Nitrite potently inhibits hypoxic and inflammatory pulmonary arterial hypertension and smooth muscle proliferation via xanthine oxidoreductase-dependent nitric oxide generation.

Background: Pulmonary arterial hypertension is a progressive proliferative vasculopathy of the small pulmonary arteries that is characterized by a primary failure of the endothelial nitric oxide and prostacyclin vasodilator pathways, coupled with dysregulated cellular proliferation. We have recently discovered that the endogenous anion salt nitrite is converted to nitric oxide in the setting of physiological and pathological hypoxia. Considering the fact that nitric oxide exhibits vasoprotective properties, we examined the effects of nitrite on experimental pulmonary arterial hypertension.

Integration of genomic and genetic approaches implicates IREB2 as a COPD susceptibility gene.

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide and is influenced by both genetic determinants and smoking. We identified genomic regions from 56 lung-tissue gene-expression microarrays and used them to select 889 SNPs to be tested for association with COPD. We genotyped SNPs in 389 severe COPD cases from the National Emphysema Treatment Trial and 424 cigarette-smoking controls from the Normative Aging Study.

NHLBI workshop: respiratory medicine-related research training for adult and pediatric fellows.

The pulmonary physician-scientist has a special niche to generate basic research findings and apply them to a clinical disease and perhaps impact its medical care. The availability of new high throughput-based scientific technologies in the "omics era" has made this an opportune time for physician scientists to prepare and embark on an academic career in respiratory disease research. However, maintaining an adequate flow through the research pipeline of physician-scientist investigators studying respiratory system diseases is currently a challenge.

The influence of radiographic phenotype and smoking status on peripheral blood biomarker patterns in chronic obstructive pulmonary disease.

Background: Chronic obstructive pulmonary disease (COPD) is characterized by both airway remodeling and parenchymal destruction. The identification of unique biomarker patterns associated with airway dominant versus parenchymal dominant patterns would support the existence of unique phenotypes representing independent biologic processes. A cross-sectional study was performed to examine the association of serum biomarkers with radiographic airway and parenchymal phenotypes of COPD.

Fatty acids modulate Toll-like receptor 4 activation through regulation of receptor dimerization and recruitment into lipid rafts in a reactive oxygen species-dependent manner.

The saturated fatty acids acylated on Lipid A of lipopolysaccharide (LPS) or bacterial lipoproteins play critical roles in ligand recognition and receptor activation for Toll-like Receptor 4 (TLR4) and TLR2. The results from our previous studies demonstrated that saturated and polyunsaturated fatty acids reciprocally modulate the activation of TLR4. However, the underlying mechanism has not been understood.

The fibrotic phenotype induced by IGFBP-5 is regulated by MAPK activation and egr-1-dependent and -independent mechanisms.

We have previously shown that insulin-like growth factor (IGF) binding protein- 5 (IGFBP-5) is overexpressed in lung fibrosis and induces the production of extracellular matrix components, such as collagen and fibronectin, both in vitro and in vivo. The exact mechanism by which IGFBP-5 exerts these novel fibrotic effects is unknown. We thus examined the signaling cascades that mediate IGFBP-5-induced fibrosis.

Heme oxygenase-1/carbon monoxide: from metabolism to molecular therapy.

Heme oxygenase-1 (HO-1), a ubiquitous inducible stress-response protein, serves a major metabolic function in heme turnover. HO activity cleaves heme to form biliverdin-IXalpha, carbon monoxide (CO), and iron. Genetic experiments have revealed a central role for HO-1 in tissue homeostasis, protection against oxidative stress, and in the pathogenesis of disease.

Lipid-soluble components in cigarette smoke induce mitochondrial production of reactive oxygen species in lung epithelial cells.

Reactive oxygen species (ROS) present in cigarette smoke (CS) are thought to contribute to the development of COPD. Although CS-ROS can hardly enter airway epithelial cells, and certainly not the circulation, systemic levels of ROS have been found to be elevated in COPD patients. We hypothesize that lipophilic components present in CS can enter airway epithelial cells and increase intracellular ROS production by disturbing mitochondrial function.

Heme oxygenase-1, a critical arbitrator of cell death pathways in lung injury and disease.

Increases in cell death by programmed (i.e., apoptosis, autophagy) or nonprogrammed mechanisms (i.

Carbon monoxide prevents ventilator-induced lung injury via caveolin-1.

Objectives: Carbon monoxide (CO) can confer anti-inflammatory protection in rodent models of ventilator-induced lung injury (VILI). Caveolin-1 exerts a critical role in cellular responses to mechanical stress and has been shown to mediate cytoprotective effects of CO in vitro. We sought to determine the role of caveolin-1 in lung susceptibility to VILI in mice.

The heme oxygenase-1/carbon monoxide pathway suppresses TLR4 signaling by regulating the interaction of TLR4 with caveolin-1.

Caveolin-1 (cav-1), the principle structural protein of plasmalemmal caveolae, regulates inflammatory signaling processes originating at the membrane. We show that cav-1 bound to TLR4 and inhibited LPS-induced proinflammatory cytokine (TNF-alpha and IL-6) production in murine macrophages. Mutation analysis revealed a cav-1 binding motif in TLR4, essential for this interaction and for attenuation of proinflammatory signaling.

Analyzing autophagy in clinical tissues of lung and vascular diseases.

Autophagy, a process by which organelles and cellular proteins are encapsulated in double-membrane vesicles and subsequently degraded by lysosomes, plays a central role in cellular and tissue homeostasis. In various model systems, autophagy may be triggered by nutrient deprivation, oxidative stress, and other insults such as endoplasmic reticulum stress, hypoxia, and pathogen infection. The role of autophagy in lung physiology and homeostasis, however, has not been well studied.

Discovery of the gene signature for acute lung injury in patients with sepsis.

The acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) was described 30 yr ago, yet making a definitive diagnosis remains difficult. The identification of biomarkers obtained from peripheral blood could provide additional noninvasive means for diagnosis. To identify gene expression profiles that may be used to classify patients with ALI, 13 patients with ALI + sepsis and 20 patients with sepsis alone were recruited from the Medical Intensive Care Unit of the University of Pittsburgh Medical Center, and microarrays were performed on peripheral blood samples.

Carbon monoxide modulates alpha-smooth muscle actin and small proline rich-1a expression in fibrosis.

Carbon monoxide (CO) is a biologically active molecule produced in the body by the stress-inducible enzyme, heme oxygenase. We have previously shown that CO suppresses fibrosis in a murine bleomycin model. To investigate the mechanisms by which CO opposes fibrogenesis, we performed gene expression profiling of fibroblasts treated with transforming growth factor-beta(1) and CO.

Autophagy in chronic obstructive pulmonary disease: homeostatic or pathogenic mechanism?

Autophagy serves a critical function in cellular homeostasis by prolonging survival during nutrient deprivation. Although primarily characterized as a cell survival mechanism, the relationship between autophagy and cell death pathways remains incompletely understood. Autophagy heretofore has not been studied in the context of human pulmonary disease.

Loss of red cell chemokine scavenging promotes transfusion-related lung inflammation.

Red cell transfusions are associated with the development of acute lung injury in the critically ill. Recent evidence suggests that storage induced alterations of the red blood cell (RBC) collectively termed the "storage lesion" may be linked with adverse biologic consequences. Using a 2-event model of systemic endotoxemia followed by a secondary challenge of RBC transfusion, we investigated whether purified RBC concentrates from syngeneic C57BL/6 mice altered inflammatory responses in murine lungs.

Sphingosine 1-phosphate rescues canine LPS-induced acute lung injury and alters systemic inflammatory cytokine production in vivo.

S1P has been demonstrated to protect against the formation of lipopolysaccharide (LPS)-induced lung edema when administered concomitantly with LPS. In the current study, we sought to determine the effectiveness of S1P to attenuate lung injury in a translationally relevant canine model of ALI when administered as rescue therapy. Secondarily, we examined whether the attenuation of LPS-induced physiologic lung injury after administration of S1P was, at least in part, caused by an alteration in local and/or systemic inflammatory cytokine expression.

Identifying targets for COPD treatment through gene expression analyses.

Despite the status of chronic obstructive pulmonary disease (COPD) as a major global health problem, no currently available therapies can limit COPD progression. Therefore, an urgent need exists for the development of new and effective treatments for COPD. An improved understanding in the molecular pathogenesis of COPD can potentially identify molecular targets to facilitate the development of new therapeutic modalities.

Egr-1 regulates autophagy in cigarette smoke-induced chronic obstructive pulmonary disease.

Background: Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by abnormal cellular responses to cigarette smoke, resulting in tissue destruction and airflow limitation. Autophagy is a degradative process involving lysosomal turnover of cellular components, though its role in human diseases remains unclear.

Methodology And Principal Findings: Increased autophagy was observed in lung tissue from COPD patients, as indicated by electron microscopic analysis, as well as by increased activation of autophagic proteins (microtubule-associated protein-1 light chain-3B, LC3B, Atg4, Atg5/12, Atg7).

Network analysis of temporal effects of intermittent and sustained hypoxia on rat lungs.

Unlabelled: The molecular networks underlying the lung response to hypoxia are not fully understood. We employed systems biology approaches to study temporal effects of intermittent or sustained hypoxia on gene expression in rat lungs. We obtained gene expression profiles from rats exposed to intermittent or sustained hypoxia lasting 0-30 days and identified differentially expressed genes, their patterns, biological processes, and regulatory networks critical for lung response to intermittent or sustained hypoxia.

Caveolin-1 regulates the secretion and cytoprotection of Cyr61 in hyperoxic cell death.

Cysteine-rich 61 (Cyr61) belongs to the CCN family and mediates cell proliferation, survival, and apoptosis. Our previous studies showed that Cyr61 protected against hyperoxia-induced lung cell death via Akt phosphorylation. Caveolin-1 (cav-1), a 22-kDa transmembrane scaffolding protein, is the principal structural component of caveolae.

CX3CL1 up-regulation is associated with recruitment of CX3CR1+ mononuclear phagocytes and T lymphocytes in the lungs during cigarette smoke-induced emphysema.

CX3CR1 is expressed on monocytes, dendritic cells, macrophages, subsets of T lymphocytes, and natural killer cells and functions in diverse capacities such as leukocyte adhesion, migration, and cell survival on ligand binding. Expression of the CX3CL1 gene, whose expression product is the sole ligand for CX3CR1, is up-regulated in human lungs with chronic cigarette smoke-induced obstructive lung disease. At present, it is unknown whether CX3CL1 up-regulation is associated with the recruitment and accumulation of immune cells that express CX3CR1.

Autophagic proteins regulate cigarette smoke-induced apoptosis: protective role of heme oxygenase-1.

Cigarette smoke-induced cell death contributes to the pathogenesis of chronic obstructive pulmonary disease, though the relative roles of apoptosis and autophagy remain unclear. The inducible stress protein heme oxygenase-1 (HO-1) confers cytoprotection against oxidative stress. We examined the relationships between these processes in human bronchial epithelial cells (Beas-2b) exposed to cigarette smoke extract (CSE).

Ex vivo carbon monoxide prevents cytochrome P450 degradation and ischemia/reperfusion injury of kidney grafts.

Renal ischemia/reperfusion injury is a major complication of kidney transplantation. We tested if ex vivo delivery of carbon monoxide (CO) to the kidney would ameliorate the renal injury of cold storage that can complicate renal transplantation. Orthotopic syngeneic kidney transplantation was performed in Lewis rats following 24 h of cold preservation in University of Wisconsin solution equilibrated without or with CO (soluble CO levels about 40 microM).