scholarly journals Mammalian target of rapamycin regulates neutrophil extracellular trap formation via induction of hypoxia-inducible factor 1 α

Blood ◽  
2012 ◽  
Vol 120 (15) ◽  
pp. 3118-3125 ◽  
Author(s):  
Alison M. McInturff ◽  
Mark J. Cody ◽  
Elizabeth A. Elliott ◽  
Jared W. Glenn ◽  
Jesse W. Rowley ◽  
...  
Keyword(s):  
Cell Function ◽  
Immune Cell ◽  
Mammalian Target Of Rapamycin ◽  
Hypoxia Inducible Factor ◽  
Severe Infection ◽  
Neutrophil Extracellular Trap ◽  
Target Of Rapamycin ◽  
Human Neutrophils ◽  
Bacterial Killing ◽  
Hypoxia Inducible Factor 1

Abstract Neutrophils are highly specialized innate immune effector cells that evolved for antimicrobial host defense. In response to inflammatory stimuli and pathogens, they form neutrophil extracellular traps (NETs), which capture and kill extracellular microbes. Deficient NET formation predisposes humans to severe infection, but, paradoxically, dysregulated NET formation contributes to inflammatory vascular injury and tissue damage. The molecular pathways and signaling mechanisms that control NET formation remain largely uncharacterized. Using primary human neutrophils and genetically manipulated myeloid leukocytes differentiated to surrogate neutrophils, we found that mammalian target of rapamycin (mTOR) regulates NET formation by posttranscriptional control of expression of hypoxia-inducible factor 1 α (HIF-1α), a critical modulator of antimicrobial defenses. Next-generation RNA sequencing, assays of mRNA and protein expression, and analysis of NET deployment by live cell imaging and quantitative histone release showed that mTOR controls NET formation and translation of HIF-1α mRNA in response to lipopolysaccharide. Pharmacologic and genetic knockdown of HIF-1α expression and activity inhibited NET deployment, and inhibition of mTOR and HIF-1α inhibited NET-mediated extracellular bacterial killing. Our studies define a pathway to NET formation involving 2 master regulators of immune cell function and identify potential points of molecular intervention in strategies to modify NETs in disease.

scholarly journals Isoflurane Preconditioning Decreases Myocardial Infarction in Rabbits via  Up-regulation of Hypoxia Inducible Factor 1 That Is Mediated by Mammalian Target of Rapamycin

2008 ◽  
Vol 108 (3) ◽  
pp. 415-425 ◽  
Author(s):  
Jacob Raphael ◽  
Zhiyi Zuo ◽  
Suzan Abedat ◽  
Ronen Beeri ◽  
Yaacov Gozal
Keyword(s):  
Myocardial Infarction ◽  
Creatine Kinase ◽  
Dna Binding ◽  
Infarct Size ◽  
Mammalian Target Of Rapamycin ◽  
Hypoxia Inducible Factor ◽  
Target Of Rapamycin ◽  
Tetrazolium Chloride ◽  
Hypoxia Inducible Factor 1 ◽  
Creatine Kinase Mb

Background Volatile anesthetics are known to protect the heart against ischemia-reperfusion injury. The authors tested whether anesthetic preconditioning with isoflurane is mediated via activation of the transcription factor hypoxia inducible factor 1 (HIF-1) and evaluated the role of mammalian target of rapamycin signaling in this process. Methods New Zealand White rabbits subjected to 40 min of regional myocardial ischemia, followed by 180 min of reperfusion, were assigned to the following groups: ischemia and reperfusion (I/R) only, isoflurane (1 minimal alveolar concentration) preconditioning, and isoflurane preconditioning in the presence of the mammalian target of rapamycin inhibitor rapamycin (0.25 mg/kg). Sham-operated, isoflurane + sham, rapamycin + sham, rapamycin + I/R, and dimethyl sulfoxide + I/R groups were also included. Creatine kinase-MB levels were assessed as an indicator of myocardial damage, and infarct size was evaluated by triphenyl tetrazolium chloride staining. HIF-1alpha expression and DNA binding were assessed by Western blotting and electrophoretic mobility shift analysis, respectively. Results Isoflurane preconditioning reduced infarct size compared with the I/R group: 26 +/- 4% versus 44 +/- 6% (P < 0.05). Creatine kinase-MB concentrations in the preconditioned animals (103 +/- 8% above baseline) were lower than in the I/R group (243 +/- 12% above baseline; P < 0.05). Rapamycin inhibited the cardioprotective effect of isoflurane: myocardial infarction increased to 44 +/- 4% and creatine kinase-MB level increased to 254 +/- 9% above baseline. HIF-1alpha protein expression and DNA binding activity increased after isoflurane preconditioning compared with the ischemia group. These effects were also inhibited by rapamycin. Conclusions The current results indicate that isoflurane-induced myocardial protection involves activation of the HIF-1 pathway that is mediated by the mammalian target of rapamycin.

scholarly journals The Thyroid Hormone Inactivating Enzyme Type 3 Deiodinase is Present in Bactericidal Granules and the Cytoplasm of Human Neutrophils

Endocrinology ◽  
2016 ◽  
Vol 157 (8) ◽  
pp. 3293-3305 ◽  
Author(s):  
Anne H. van der Spek ◽  
Flavia F. Bloise ◽  
Wikky Tigchelaar ◽  
Monica Dentice ◽  
Domenico Salvatore ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Subcellular Localization ◽  
Subcellular Location ◽  
Essential Elements ◽  
Neutrophil Extracellular Trap ◽  
Human Neutrophils ◽  
Transcriptional Level ◽  
Bacterial Killing ◽  
Effector Cells ◽  
Type 3

Neutrophils are important effector cells of the innate immune system. Thyroid hormone (TH) is thought to play an important role in their function. Intracellular TH levels are regulated by the deiodinating enzymes. The TH-inactivating type 3 deiodinase (D3) is expressed in infiltrating murine neutrophils, and D3 knockout mice show impaired bacterial killing upon infection. This suggests that D3 plays an important role in the bacterial killing capacity of neutrophils. The mechanism behind this effect is unknown. We aimed to assess the presence of D3 in human neutrophils, and determine its subcellular localization using confocal and electron microscopy, because this could give important clues about its function in these cells. D3 appeared to be present in the cytoplasm and in myeloperoxidase containing azurophilic granules and as well as lactoferrin containing specific granules within human neutrophils. This subcellular localization did not change upon activation of the cells. D3 is observed intracellularly during neutrophil extracellular trap formation, followed by a reduction of D3 staining after release of the neutrophil extracellular traps into the extracellular space. At the transcriptional level, human neutrophils expressed additional essential elements of TH metabolism, including TH transporters and TH receptors. Here, we demonstrate the presence and subcellular location of D3 in human neutrophils for the first time and propose a model, in which D3 plays a role in the bacterial killing capacity of neutrophils either through generation of iodide for the myeloperoxidase system or through modulation of intracellular TH bioavailability.

Mammalian target of rapamycin complex 1 activation in podocytes promotes cellular crescent formation

2014 ◽  
Vol 307 (9) ◽  
pp. F1023-F1032 ◽  
Author(s):  
Junhua Mao ◽  
Zhifeng Zeng ◽  
Zhuo Xu ◽  
Jiangzhong Li ◽  
Lei Jiang ◽  
...  
Keyword(s):  
Mammalian Target Of Rapamycin ◽  
Hypoxia Inducible Factor ◽  
Target Of Rapamycin ◽  
Crescent Formation ◽  
Glomerular Diseases ◽  
Mtorc1 Signaling ◽  
Cellular Crescent ◽  
Underlying Mechanisms ◽  
Mtorc1 Activation ◽  
Glomerular Tuft

Podocytes play a key role in the formation of cellular crescents in experimental and human diseases. However, the underlying mechanisms for podocytes in promoting crescent formation need further investigation. Here, we demonstrated that mammalian target of rapamycin complex 1 (mTORC1) signaling was remarkably activated and hypoxia-inducible factor (HIF) 1α expression was largely induced in cellular crescents from patients with crescentic glomerular diseases. Specific deletion of Tsc1 in podocytes led to mTORC1 activation in podocytes and kidney dysfunction in mice. Interestingly, 33 of 36 knockouts developed cellular or mixed cellular and fibrous crescents at 7 wk of age (14.19 ± 3.86% of total glomeruli in knockouts vs. 0% in control littermates, n = 12–36, P = 0.04). All of the seven knockouts developed crescents at 12 wk of age (30.92 ± 11.961% of total glomeruli in knockouts vs. 0% in control littermates, n = 4–7, P = 0.002). Most notably, bridging cells between the glomerular tuft and the parietal basement membrane as well as the cellular crescents were immunostaining positive for WT1, p-S6, HIF1α, and Cxcr4. Furthermore, continuously administrating rapamycin starting at 7 wk of age for 5 wk abolished crescents as well as the induction of p-S6, HIF1α, and Cxcr4 in the glomeruli from the knockouts. Together, it is concluded that mTORC1 activation in podocytes promotes cellular crescent formation, and targeting this signaling may shed new light on the treatment of patients with crescentic glomerular diseases.

scholarly journals Flavored e-cigarette liquids and cinnamaldehyde impair respiratory innate immune cell function

2017 ◽  
Vol 313 (2) ◽  
pp. L278-L292 ◽  
Author(s):  
Phillip W. Clapp ◽  
Erica A. Pawlak ◽  
Justin T. Lackey ◽  
James E. Keating ◽  
Steven L. Reeber ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nk Cells ◽  
Cell Function ◽  
Immune Cell ◽  
Innate Immune ◽  
Neutrophil Extracellular Trap ◽  
Immune Functions ◽  
Immune Cell Function ◽  
Functional Responses ◽  
Macrophage Phagocytosis

Innate immune cells of the respiratory tract are the first line of defense against pathogenic and environmental insults. Failure of these cells to perform their immune functions leaves the host susceptible to infection and may contribute to impaired resolution of inflammation. While combustible tobacco cigarettes have been shown to suppress respiratory immune cell function, the effects of flavored electronic cigarette liquids (e-liquids) and individual flavoring agents on respiratory immune cell responses are unknown. We investigated the effects of seven flavored nicotine-free e-liquids on primary human alveolar macrophages, neutrophils, and natural killer (NK) cells. Cells were challenged with a range of e-liquid dilutions and assayed for their functional responses to pathogenic stimuli. End points included phagocytic capacity (neutrophils and macrophages), neutrophil extracellular trap formation, proinflammatory cytokine production, and cell-mediated cytotoxic response (NK cells). E-liquids were then analyzed via mass spectrometry to identify individual flavoring components. Three cinnamaldehyde-containing e-liquids exhibited dose-dependent broadly immunosuppressive effects. Quantitative mass spectrometry was used to determine concentrations of cinnamaldehyde in each of the three e-liquids, and cells were subsequently challenged with a range of cinnamaldehyde concentrations. Cinnamaldehyde alone recapitulated the impaired function observed with e-liquid exposures, and cinnamaldehyde-induced suppression of macrophage phagocytosis was reversed by addition of the small-molecule reducing agent 1,4-dithiothreitol. We conclude that cinnamaldehyde has the potential to impair respiratory immune cell function, illustrating an immediate need for further toxicological evaluation of chemical flavoring agents to inform regulation governing their use in e-liquid formulations.

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