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Pioglitazone restores phagocyte mitochondrial oxidants and bactericidal capacity in chronic granulomatous disease.

ABSTRACT: Deficient production of reactive oxygen species (ROS) by the phagocyte nicotinamide adenine dinucleotide (NADPH) oxidase in patients with chronic granulomatous disease (CGD) results in susceptibility to certain pathogens secondary to impaired oxidative killing and mobilization of other phagocyte defenses. Peroxisome proliferator-activated receptor (PPAR) ? agonists, including pioglitazone, approved for type 2 diabetes therapy alter cellular metabolism and can heighten ROS production. It was hypothesized that pioglitazone treatment of gp91(phox-/-) mice, a murine model of human CGD, would enhance phagocyte oxidant production and killing of Staphylococcus aureus, a significant pathogen in patients with this disorder.We sought to determine whether pioglitazone treatment of gp91(phox-/-) mice enhanced phagocyte oxidant production and host defense.Wild-type and gp91(phox-/-) mice were treated with the PPAR? agonist pioglitazone, and phagocyte ROS and killing of S aureus were investigated.As demonstrated by 3 different ROS-sensing probes, short-term treatment of gp91(phox-/-) mice with pioglitazone enhanced stimulated ROS production in neutrophils and monocytes from blood and neutrophils and inflammatory macrophages recruited to tissues. Mitochondria were identified as the source of ROS. Findings were replicated in human monocytes from patients with CGD after ex vivo pioglitazone treatment. Importantly, although mitochondrial (mt)ROS were deficient in gp91(phox-/-) phagocytes, their restoration with treatment significantly enabled killing of S aureus both ex vivo and in vivo.Together, the data support the hypothesis that signaling from the NADPH oxidase under normal circumstances governs phagocyte mtROS production and that such signaling is lacking in the absence of a functioning phagocyte oxidase. PPAR? agonism appears to bypass the need for the NADPH oxidase for enhanced mtROS production and partially restores host defense in CGD.

SUBMITTER: Fernandez-Boyanapalli RF

PROVIDER: S-EPMC4331116 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature

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Pioglitazone restores phagocyte mitochondrial oxidants and bactericidal capacity in chronic granulomatous disease.

Fernandez-Boyanapalli Ruby F RF Frasch S Courtney SC Thomas Stacey M SM Malcolm Kenneth C KC Nicks Michael M Harbeck Ronald J RJ Jakubzick Claudia V CV Nemenoff Raphael R Henson Peter M PM Holland Steven M SM Bratton Donna L DL

The Journal of allergy and clinical immunology 20141210 2

<h4>Background</h4>Deficient production of reactive oxygen species (ROS) by the phagocyte nicotinamide adenine dinucleotide (NADPH) oxidase in patients with chronic granulomatous disease (CGD) results in susceptibility to certain pathogens secondary to impaired oxidative killing and mobilization of other phagocyte defenses. Peroxisome proliferator-activated receptor (PPAR) γ agonists, including pioglitazone, approved for type 2 diabetes therapy alter cellular metabolism and can heighten ROS prod ...[more]

PMID: 25498313

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Project description:Human exposure to carbon nanotubes (CNT) has been associated with the development of pulmonary sarcoid-like granulomatous disease. Our previous studies demonstrated that multi-walled carbon nanotubes (MWCNT) induced chronic pulmonary granulomatous inflammation in mice. Granuloma formation was accompanied by decreased peroxisome proliferator-activated receptor gamma (PPARγ) and disrupted intracellular lipid homeostasis in alveolar macrophages. Others have shown that PPARγ activation increases mitochondrial fatty acid oxidation (FAO) to reduce free fatty acid accumulation. Hence, we hypothesized that the disrupted lipid metabolism suppresses mitochondrial FAO. To test our hypothesis, C57BL/6 J mice were instilled by an oropharyngeal route with 100 μg MWCNT freshly suspended in 35 % Infasurf. Control sham mice received vehicle alone. Sixty days following instillation, mitochondrial FAO was measured in permeabilized bronchoalveolar lavage (BAL) cells. MWCNT instillation reduced the mitochondrial oxygen consumption rate of BAL cells in the presence of palmitoyl-carnitine as mitochondrial fuel. MWCNT also reduced mRNA expression of mitochondrial genes regulating FAO, carnitine palmitoyl transferase-1 (CPT1), carnitine palmitoyl transferase-2 (CPT2), hydroxyacyl-CoA dehydrogenase subunit beta (HADHB), and PPARγ coactivator 1 alpha (PPARGC1A). Importantly, both oxidative stress and apoptosis in alveolar macrophages and lung tissues of MWCNT-instilled mice were increased. Because macrophage PPARγ expression has been reported to be controlled by miR-27b which is known to induce oxidative stress and apoptosis, we measured the expression of miR-27b. Results indicated elevated levels in alveolar macrophages from MWCNT-instilled mice compared to controls. Given that inhibition of FAO and apoptosis are linked to M1 and M2 macrophage activation, respectively, the expression of both M1 and M2 key indicator genes were measured. Interestingly, results showed that both M1 and M2 phenotypes of alveolar macrophages were activated in MWCNT-instilled mice. In conclusion, alveolar macrophages of MWCNT-instilled mice had increased miR-27b expression, which may reduce the expression of PPARγ resulting in attenuation of FAO. This reduction in FAO may lead to activation of M1 macrophages. The upregulation of miR-27b may also induce apoptosis, which in turn can cause M2 activation of alveolar macrophages. These observations indicate a possible role of miR-27b in impaired mitochondrial function in the chronic activation of alveolar macrophages by MWCNT and the development of chronic pulmonary granulomatous inflammation.

Project description:This study will determine if the drug infliximab is safe for treating inflammatory bowel disease (IBD) in patients with chronic granulomatous disease (CGD). IBD is an inflammation or irritation of the gut that leads to symptoms such as diarrhea, bloating and stomach cramps. CGD is an inherited disease affecting white blood cells called neutrophils in which patients are susceptible to repeated bacterial and fungal infections. They also have a higher incidence of some autoimmune diseases, such as IBD. Infliximab is approved to treat Crohn’s disease, an IBD similar to that seen in patients with CGD. Patients 10 years of age and older with CGD and IBD may be eligible for this study. Candidates are screened with a medical history, physical examination, blood and urine tests, electrocardiogram (EKG), tuberculosis skin test (PPD skin testing), and stool test for the presence of infections. Additional tests may be done, including colonoscopy (procedure using a flexible tube through the rectum to examine the lining of the gut) and imaging studies such as an x-ray, chest CT scan (test using a special x-ray machine), MRI (test using a magnetic field and radio waves), and barium studies (study using a drinkable solution of barium to help enhance the x-ray pictures of the gut). Participants are divided into patients with IBD symptoms (Group 1) and patients without IBD symptoms (Group 2) for the following procedures: Group 1 Patients are evaluated every 6 months with a medical history and physical examination for signs and symptoms of IBD. Patients who are taking moderate to high doses of steroid medications have their medication slowly lowered (tapered) and are evaluated every 3 months for a total of 2 years. Patients in this group who start to develop IBD symptoms are moved to Group 2 for treatment with infliximab (see below). Group 2 Patients in Group 2 receive infliximab infusions at 2-week intervals for three doses. The drug is given over a 2-hour period through a catheter placed in a vein. Patients are evaluated with a medical history, physical exam, and blood tests the day of each dose. One week after the last dose, they have another evaluation, including a colonoscopy. Patients who respond well to infliximab may continue to receive the drug every 2 months for a total of 1 year, with evaluations at every dosing visit. At the end of the first year of receiving infliximab, all patients have follow-up evaluations every 6 months for a total of 2 years. Group 3 Subjects who volunteer to undergo colonoscopy and research biopsies that serve as controls for evaluation of the patient gut samples.

Project description:BackgroundPatients with chronic granulomatous disease (CGD) experience immunodeficiency because of defects in the phagocyte NADPH oxidase and the concomitant reduction in reactive oxygen intermediates. This may result in a reduction in atherosclerotic injury.Methods and resultsWe prospectively assessed the prevalence of cardiovascular risk factors, biomarkers of inflammation and neutrophil activation, and the presence of magnetic resonance imaging and computed tomography quantified subclinical atherosclerosis in the carotid and coronary arteries of 41 patients with CGD and 25 healthy controls in the same age range. Univariable and multivariable associations among risk factors, inflammatory markers, and atherosclerosis burden were assessed. Patients with CGD had significant elevations in traditional risk factors and inflammatory markers compared with control subjects, including hypertension, high-sensitivity C-reactive protein, oxidized low-density lipoprotein, and low high-density lipoprotein. Despite this, patients with CGD had a 22% lower internal carotid artery wall volume compared with control subjects (361.3±76.4 mm(3) versus 463.5±104.7 mm(3); P<0.001). This difference was comparable in p47(phox)- and gp91(phox)-deficient subtypes of CGD and independent of risk factors in multivariate regression analysis. In contrast, the prevalence of coronary arterial calcification was similar between patients with CGD and control subjects (14.6%, CGD; 6.3%, controls; P=0.39).ConclusionsThe observation by magnetic resonance imaging and computerized tomography of reduced carotid but not coronary artery atherosclerosis in patients with CGD despite the high prevalence of traditional risk factors raises questions about the role of NADPH oxidase in the pathogenesis of clinically significant atherosclerosis. Additional high-resolution studies in multiple vascular beds are required to address the therapeutic potential of NADPH oxidase inhibition in cardiovascular diseases.Clinical trial registration urlhttp://www.clinicaltrials.gov. Unique identifier: NCT01063309.

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Pioglitazone restores phagocyte mitochondrial oxidants and bactericidal capacity in chronic granulomatous disease.

Publications

Pioglitazone restores phagocyte mitochondrial oxidants and bactericidal capacity in chronic granulomatous disease.

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