1
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Farias-Jofre M, Romero R, Galaz J, Xu Y, Tao L, Demery-Poulos C, Arenas-Hernandez M, Bhatti G, Liu Z, Kawahara N, Kanninen T, Shaffer Z, Chaiworapongsa T, Theis KR, Tarca AL, Gomez-Lopez N. Pregnancy tailors endotoxin-induced monocyte and neutrophil responses in the maternal circulation. Inflamm Res 2022; 71:653-668. [PMID: 35445873 PMCID: PMC9021564 DOI: 10.1007/s00011-022-01569-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 01/29/2023] Open
Abstract
Objective To comprehensively characterize monocyte and neutrophil responses to E. coli and its product [lipopolysaccharide (LPS) or endotoxin] in vitro during pregnancy. Material or subjects Peripheral blood was collected from pregnant women during the third trimester (n = 20) and from non-pregnant women (n = 20). Methods The number, phagocytic activity, and reactive oxygen species (ROS) production of peripheral monocytes and neutrophils were investigated using flow cytometry. The phenotypes of peripheral monocytes and neutrophils after acute or chronic LPS stimulation were also determined using flow cytometry. Cytokine profiles were quantified for LPS-stimulated peripheral blood mononuclear cells (PBMCs) and a whole blood TruCulture® system using a multiplex immunoassay. Results Increased number, phagocytic activity, and ROS production capacity of monocytes and neutrophils were found in pregnant compared to non-pregnant women. Additionally, specific subsets of pro-inflammatory monocytes (IL-6+CD14+ or MIP-1α+CD14+ cells) and neutrophils (IL-1β+CD15+ or MIP-1β+CD15+ cells) were increased in pregnant women in response to acute LPS stimulation. Moreover, distinct subsets of intermediate-activated monocytes expressing CD142, IL-6, and IL-1RA were increased in pregnant women upon chronic LPS stimulation. Last, pregnant women displayed a different cytokine profile than non-pregnant women in LPS-stimulated PBMCs and in whole blood. Conclusions Pregnancy tailors the immune responses of circulating monocytes and neutrophils to endotoxin, a Gram-negative bacterial product. Supplementary Information The online version contains supplementary material available at 10.1007/s00011-022-01569-z.
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Affiliation(s)
- Marcelo Farias-Jofre
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA.,Division of Obstetrics and Gynecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Catolica de Chile, 8330024, Santiago, Chile
| | - Roberto Romero
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA. .,Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, Michigan, 48824, USA. .,Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, 48201, USA. .,Detroit Medical Center, Detroit, MI, 48201, USA.
| | - Jose Galaz
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA.,Division of Obstetrics and Gynecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Catolica de Chile, 8330024, Santiago, Chile
| | - Yi Xu
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Li Tao
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Catherine Demery-Poulos
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Marcia Arenas-Hernandez
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Gaurav Bhatti
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Zhenjie Liu
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Naoki Kawahara
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Tomi Kanninen
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Zachary Shaffer
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Tinnakorn Chaiworapongsa
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA
| | - Kevin R Theis
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA.,Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Adi L Tarca
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA.,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA.,Department of Computer Science, Wayne State University College of Engineering, Detroit, MI, 48201, USA
| | - Nardhy Gomez-Lopez
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS), Detroit, MI, 48201, USA. .,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, 275 E. Hancock, Detroit, MI, 48201, USA. .,Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI, 48201, USA.
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2
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Petty HR. Enzyme Trafficking and Co-Clustering Precede and Accurately Predict Human Breast Cancer Recurrences: An Interdisciplinary Review. Am J Physiol Cell Physiol 2022; 322:C991-C1010. [PMID: 35385324 DOI: 10.1152/ajpcell.00042.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Although great effort has been expended to understand cancer's origins, less attention has been given to the primary cause of cancer deaths - cancer recurrences and their sequelae. This interdisciplinary review addresses mechanistic features of aggressive cancer by studying metabolic enzyme patterns within ductal carcinoma in situ (DCIS) of the breast lesions. DCIS lesions from patients who did or did not experience a breast cancer recurrence were compared. Several proteins, including phospho-Ser226-glucose transporter type 1, phosphofructokinase type L and phosphofructokinase/fructose 2,6-bisphosphatase type 4 are found in nucleoli of ductal epithelial cells in samples from patients who will not subsequently recur, but traffic to the cell periphery in samples from patients who will experience a cancer recurrence. Large co-clusters of enzymes near plasmalemmata will enhance product formation because enzyme concentrations in clusters are very high while solvent molecules and solutes diffuse through small channels. These structural changes will accelerate aerobic glycolysis. Agglomerations of pentose phosphate pathway and glutathione synthesis enzymes enhance GSH formation. As aggressive cancer lesions are incomplete at early stages, they may be unrecognizable. We have found that machine learning provides superior analyses of tissue images and may be used to identify biomarker patterns associated with recurrent and non-recurrent patients with high accuracy. This suggests a new prognostic test to predict DCIS patients who are likely to recur and those who are at low risk for recurrence. Mechanistic interpretations provide a deeper understanding of anti-cancer drug action and suggest that aggressive metastatic cancer cells are sensitive to reductive chemotherapy.
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Affiliation(s)
- Howard R Petty
- Dept. of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI, United States
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3
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Briones-Claudett KH, Briones-Claudett MH, Murillo Vasconez RA, Alfonzo Pacheco MF, Martinez Armijo EA, Briones Zamora KH, Briones Marquez DC, Franco Chávez D, Grunauer M. Invasive Subacute Pulmonary Aspergillosis After Puerperal Sepsis: Case Report. J Investig Med High Impact Case Rep 2020; 8:2324709620977707. [PMID: 33307837 PMCID: PMC7739074 DOI: 10.1177/2324709620977707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Subacute invasive aspergillosis is an infection that locally destroys lung parenchyma, and it affects patients with mild immunocompromise. The diagnosis is made by clinical symptoms, imaging, and laboratory results related to the infection. Early diagnosis and treatment is imperative for a favorable patient outcome. In this article, we present the case of a 19-year-old woman who was admitted to the intensive care unit for puerperal sepsis where a hysterectomy was performed. During her hospitalization, she presented atelectasis of the left lung and hemodynamic instability. Chest X-ray and chest computed tomography scan were performed and showed round opacities. It was decided to perform flexible bronchoscopy with bronchoalveolar lavage. An unusual subacute form of implementation of aspergillosis was confirmed by a bronchoalveolar lavage culture that showed the presence of Aspergillus. Images taken during bronchoscopy revealed Aspergillus implantation in the lung and serum galactomannan antigen test was positive. Voriconazole was introduced, 200 mg daily. The patient showed clinical improvement and was discharged from our hospital. We conclude that subacute invasive aspergillosis is a serious infection that can lead to high mortality. Bronchoscopy with bronchoalveolar lavage allows access and effective visualization of the airway as well as sampling for Aspergillus identification.
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Affiliation(s)
- Killen H Briones-Claudett
- Universidad de Guayaquil, Guayaquil, Ecuador.,Physiology and Respiratory-Center Briones-Claudett, Guayaquil, Ecuador.,Ecuadorian Institute of Social Security, Babahoyo, Ecuador
| | - Mónica H Briones-Claudett
- Physiology and Respiratory-Center Briones-Claudett, Guayaquil, Ecuador.,Ecuadorian Institute of Social Security, Babahoyo, Ecuador
| | | | | | | | - Killen H Briones Zamora
- Physiology and Respiratory-Center Briones-Claudett, Guayaquil, Ecuador.,Universidad Espíritu Santo, Samborondón, Ecuador
| | - Diana C Briones Marquez
- Universidad de Guayaquil, Guayaquil, Ecuador.,Physiology and Respiratory-Center Briones-Claudett, Guayaquil, Ecuador
| | | | - Michelle Grunauer
- Universidad San Francisco de Quito, Quito, Ecuador.,Hospital de los Valles, Quito, Ecuador
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4
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Abu-Raya B, Michalski C, Sadarangani M, Lavoie PM. Maternal Immunological Adaptation During Normal Pregnancy. Front Immunol 2020; 11:575197. [PMID: 33133091 PMCID: PMC7579415 DOI: 10.3389/fimmu.2020.575197] [Citation(s) in RCA: 242] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/18/2020] [Indexed: 12/25/2022] Open
Abstract
The risk and severity of specific infections are increased during pregnancy due to a combination of physiological and immunological changes. Characterizing the maternal immune system during pregnancy is important to understand how the maternal immune system maintains tolerance towards the allogeneic fetus. This may also inform strategies to prevent maternal fatalities due to infections and optimize maternal vaccination to best protect the mother-fetus dyad and the infant after birth. In this review, we describe what is known about the immunological changes that occur during a normal pregnancy.
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Affiliation(s)
- Bahaa Abu-Raya
- Vaccine Evaluation Center, BC Children's Hospital Research Institute, Vancouver, BC, Canada.,BC Children's Hospital Research Institute, Vancouver, BC, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada.,Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Christina Michalski
- BC Children's Hospital Research Institute, Vancouver, BC, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada.,Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Manish Sadarangani
- Vaccine Evaluation Center, BC Children's Hospital Research Institute, Vancouver, BC, Canada.,BC Children's Hospital Research Institute, Vancouver, BC, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada.,Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Pascal M Lavoie
- BC Children's Hospital Research Institute, Vancouver, BC, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada.,Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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5
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Youssef SR, Hendawy SF, Boshnak NH, Sedhom MS. Effect of intra-cellular trafficking on flow cytometric measurement of neutrophil's oxidative status in iron deficient pregnant females. J Clin Lab Anal 2017; 32. [PMID: 28345771 DOI: 10.1002/jcla.22210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/22/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Iron deficiency and iron deficiency anemia are prevalent among pregnant women particularly in developing countries. This study aimed to evaluate the iron status among Egyptian pregnant women and its impact on their neutrophil's count and antimicrobial functions. METHOD Ninety pregnant females underwent complete blood count, iron profile, flow cytometric studies for neutrophil myeloperoxidase expression & oxidative burst using dihydrorhodamine 123 (DHR) after phorbol-12-myristate-13-acetate (PMA) stimulation as well as neutrophil phagocytic and lytic indices. RESULTS According to percent saturation 54/90 women (60%) were iron deficient (<15% saturation) (cases) and 36/90 (40%) were iron sufficient (controls). A higher proportion of iron deficient pregnant women were in their third trimester compared to controls. No significant difference was found between the iron deficient & sufficient groups as regards anemia despite a positive correlation between haemoglobin level and percent saturation (P=.02). Both the phagocytic and lytic indices were significantly lower among the cases compared to controls (P=.014 & .002 respectively). Cases and controls were comparable as regards flow cytometric studies of neutrophils' myeloperoxidase and oxidative burst (P>.05). No significant correlation was found between any of the iron profile parameters and the oxidative burst by flow cytometry. CONCLUSION Functional microphage assay (phagocytic and lytic indices) may be more relevant and cost effective than flow cytometry assays of myeloperoxidase and oxidative burst in reflecting either iron status or cellular immunity in pregnancy.
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Affiliation(s)
- Soha R Youssef
- Department of Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Sherif F Hendawy
- Department of Gynecology and Obstetrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Noha H Boshnak
- Department of Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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6
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Giaglis S, Stoikou M, Sur Chowdhury C, Schaefer G, Grimolizzi F, Rossi SW, Hoesli IM, Lapaire O, Hasler P, Hahn S. Multimodal Regulation of NET Formation in Pregnancy: Progesterone Antagonizes the Pro-NETotic Effect of Estrogen and G-CSF. Front Immunol 2016; 7:565. [PMID: 27994595 PMCID: PMC5136684 DOI: 10.3389/fimmu.2016.00565] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/22/2016] [Indexed: 12/21/2022] Open
Abstract
Human pregnancy is associated with a mild pro-inflammatory state, characterized by circulatory neutrophil activation. In order to explore the mechanism underlying this alteration, we examined NETosis during normal gestation. Our data indicate that neutrophils exhibit a pro-NETotic state, modulated in a multimodal manner during pregnancy. In general, circulatory granulocyte colony-stimulating factor, the levels of which increase during gestation, promotes neutrophil extracellular trap (NET) formation. Early in pregnancy, NETosis is enhanced by chorionic gonadotropin, whereas toward term is stimulated by estrogen. A complex interaction between estrogen and progesterone arises, wherein progesterone restrains the NETotic process. In this state, extensive histone citrullination is evident, yet full NETosis is inhibited. This coincides with the inability of neutrophil elastase to translocate from the cytoplasm to the nucleus and is regulated by progesterone. Our findings provide new insight concerning gestational and hormone-driven pathologies, since neutrophil recruitment, activation, and NET release could be associated with excessive endothelial and placental injury.
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Affiliation(s)
- Stavros Giaglis
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Rheumatology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Maria Stoikou
- Department of Biomedicine, University Hospital Basel , Basel , Switzerland
| | | | - Guenther Schaefer
- Department of Biomedicine, University Hospital Basel , Basel , Switzerland
| | - Franco Grimolizzi
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department Clinical Sciences, Polytechnic University Marche, Ancona, Italy
| | - Simona W Rossi
- Department of Biomedicine, University Hospital Basel , Basel , Switzerland
| | | | - Olav Lapaire
- University Women's Hospital, University Hospital Basel , Basel , Switzerland
| | - Paul Hasler
- Department of Rheumatology, Cantonal Hospital Aarau , Aarau , Switzerland
| | - Sinuhe Hahn
- Department of Biomedicine, University Hospital Basel , Basel , Switzerland
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7
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Nagy C, Haschemi A. Time and Demand are Two Critical Dimensions of Immunometabolism: The Process of Macrophage Activation and the Pentose Phosphate Pathway. Front Immunol 2015; 6:164. [PMID: 25904920 PMCID: PMC4389563 DOI: 10.3389/fimmu.2015.00164] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/26/2015] [Indexed: 01/08/2023] Open
Abstract
A process is a function of time; in immunometabolism, this is reflected by the stepwise adaptation of metabolism to sustain the bio-energetic demand of an immune-response in its various states and shades. This perspective article starts by presenting an early attempt to investigate the physiology of inflammation, in order to illustrate one of the basic concepts of immunometabolism, wherein an adapted metabolism of infiltrating immune cells affects tissue function and inflammation. We then focus on the process of macrophage activation and aim to delineate the factor time within the current molecular context of metabolic-rewiring important for adapting primary carbohydrate metabolism. In the last section, we will provide information on how the pentose phosphate pathway may be of importance to provide both nucleotide precursors and redox-equivalents, and speculate how carbon-scrambling events in the non-oxidative pentose phosphate pathway might be regulated within cells by demand. We conclude that the adapted metabolism of inflammation is specific in respect to the effector-function and appears as a well-orchestrated event, dynamic by nature, and based on a functional interplay of signaling- and metabolic-pathways.
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Affiliation(s)
- Csörsz Nagy
- Department of Laboratory Medicine (KILM), Medical University of Vienna , Vienna , Austria
| | - Arvand Haschemi
- Department of Laboratory Medicine (KILM), Medical University of Vienna , Vienna , Austria
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8
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Kwong C, Gilman-Sachs A, Beaman K. An independent endocytic pathway stimulates different monocyte subsets by the a2 N-terminus domain of vacuolar-ATPase. Oncoimmunology 2014; 2:e22978. [PMID: 23483532 PMCID: PMC3583941 DOI: 10.4161/onci.22978] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The vacuolar ATPase (V-ATPase) plays an important role in tumor progression and metastases. A novel peptide from the a2 isoform of V-ATPase called a2NTD has been shown to exert an immunoregulatory role in the tumor microenvironment by controlling the maturation of monocytes toward a tumor-associated macrophage phenotype. Our data indicate that a2NTD binds to the surface of monocytes. a2NTD was preferentially endocytosed by pro-inflammatory monocytes bearing a CD14++CD16+ phenotype, which is associated with the monocyte-to-macrophage maturation process. Both a2NTD binding and internalization led to production of the pro-inflammatory cytokines interleukin (IL)-1α and IL-1β by CD14++CD16- (classical) and CD14++CD16+ (intermediate) monocytes. a2NTD was internalized via a macropinocytosis mechanism utilizing scavenger receptors. However, the inhibition of a2NTD endocytosis did not reduce cytokine production by monocytes. This points to the existence of two receptors that respond to a2NTD: scavengers receptors that mediate cellular uptake and an hitherto unidentified receptor stimulating the production of inflammatory cytokines. Both of these monocyte receptors may be important in generating the localized inflammation that is often required to promote tumor growth and hence may constitute novel targets for the development of anticancer drugs.
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Affiliation(s)
- Christina Kwong
- Department of Microbiology and Immunology; Chicago Medical School; Rosalind Franklin University of Medicine and Science; Chicago, IL USA
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9
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Ssemaganda A, Kindinger L, Bergin P, Nielsen L, Mpendo J, Ssetaala A, Kiwanuka N, Munder M, Teoh TG, Kropf P, Müller I. Characterization of neutrophil subsets in healthy human pregnancies. PLoS One 2014; 9:e85696. [PMID: 24551035 PMCID: PMC3923728 DOI: 10.1371/journal.pone.0085696] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 12/06/2013] [Indexed: 12/21/2022] Open
Abstract
We have previously shown that in successful pregnancies increased arginase activity is a mechanism that contributes to the suppression of the maternal immune system. We identified the main type of arginase-expressing cells as a population of activated low-density granulocytes (LDGs) in peripheral blood mononuclear cells and in term placentae. In the present study, we analyzed the phenotype of LDGs and compared it to the phenotype of normal density granulocytes (NDGs) in maternal peripheral blood, placental biopsies and cord blood. Our data reveal that only LDGs but no NDGs could be detected in placental biopsies. Phenotypically, NDGs and LDGs from both maternal and cord blood expressed different levels of maturation, activation and degranulation markers. NDGs from the maternal and cord blood were phenotypically similar, while maternal, cord and placental LDGs showed different expression levels of CD66b. LDGs present in cord blood expressed higher levels of arginase compared to maternal and placental LDGs. In summary, our results show that in maternal and cord blood, two phenotypically different populations of neutrophils can be identified, whereas in term placentae, only activated neutrophils are present.
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Affiliation(s)
- Aloysius Ssemaganda
- Uganda Virus Research Institute - International AIDS Vaccine Initiative, Entebbe, Uganda
| | - Lindsay Kindinger
- Department of Obstetrics and Gynecology, St. Mary's Hospital, London, United Kingdom
| | - Philip Bergin
- International AIDS Vaccine Initiative Human Immunology Laboratory, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Leslie Nielsen
- Uganda Virus Research Institute - International AIDS Vaccine Initiative, Entebbe, Uganda
| | - Juliet Mpendo
- Uganda Virus Research Institute - International AIDS Vaccine Initiative, Entebbe, Uganda
| | - Ali Ssetaala
- Uganda Virus Research Institute - International AIDS Vaccine Initiative, Entebbe, Uganda
| | - Noah Kiwanuka
- Uganda Virus Research Institute - International AIDS Vaccine Initiative, Entebbe, Uganda ; School of Public Health, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Markus Munder
- Third Department of Medicine, Hematology, Oncology and Pneumology, University Medical Center, Mainz, Germany
| | - Tiong Ghee Teoh
- Department of Obstetrics and Gynecology, St. Mary's Hospital, London, United Kingdom
| | - Pascale Kropf
- Section of Immunology, Department of Medicine, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Ingrid Müller
- Section of Immunology, Department of Medicine, Faculty of Medicine, Imperial College London, London, United Kingdom
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10
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Xu Y, Madsen-Bouterse SA, Romero R, Hassan S, Mittal P, Elfline M, Zhu A, Petty HR. Leukocyte pyruvate kinase expression is reduced in normal human pregnancy but not in pre-eclampsia. Am J Reprod Immunol 2010; 64:137-51. [PMID: 20560913 PMCID: PMC3045787 DOI: 10.1111/j.1600-0897.2010.00881.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
PROBLEM Emerging evidence suggests that metabolism influences immune cell signaling and immunoregulation. To examine the immunoregulatory role of glycolysis in pregnancy, we evaluated the properties of pyruvate kinase in leukocytes from non-pregnant women and those with normal pregnancy and pre-eclampsia. METHOD OF STUDY We evaluated pyruvate kinase expression in lymphocytes and neutrophils from non-pregnant, pregnant, and pre-eclampsia patients using fluorescence microscopy and flow cytometry. Leukocyte pyruvate kinase activity and pyruvate concentrations were also evaluated. To study pyruvate's effect on signaling, we labeled Jurkat T cells with Ca(2+) dyes and measured cell responses in the presence of agents influencing intracellular pyruvate. RESULTS The expression of pyruvate kinase is reduced in lymphocytes and neutrophils from normal pregnant women in comparison with those of non-pregnant women and pre-eclampsia patients. Similarly, the activity of pyruvate kinase and the intracellular pyruvate concentration are reduced in leukocytes of normal pregnant women in comparison with non-pregnant women and women with pre-eclampsia. Using Jurkat cells as a model of leukocyte signaling, we have shown that perturbations of intracellular pyruvate influence Ca(2+) signals. CONCLUSION Normal pregnancy is characterized by reduced pyruvate kinase expression within lymphocytes and neutrophils. We speculate that reduced pyruvate kinase expression modifies immune cell responses due to reduced pyruvate concentrations.
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Affiliation(s)
- Yi Xu
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201
| | - Sally A. Madsen-Bouterse
- Perinatology Research Branch, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of NIH, Bethesda, Maryland and Detroit, Michigan 48201
| | - Roberto Romero
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201
- Perinatology Research Branch, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of NIH, Bethesda, Maryland and Detroit, Michigan 48201
- Center of Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan; Hutzel Women's Hospital at the Detroit Medical Center, Detroit, Michigan, 3990 John R. Rd., 4 Brush South, Detroit, MI 48201
| | - Sonia Hassan
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201
| | - Pooja Mittal
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201
| | - Megan Elfline
- Department of Ophthalmology and Visual Sciences, The University of Michigan Medical School, Ann Arbor, MI 48105
| | - Aiping Zhu
- Department of Ophthalmology and Visual Sciences, The University of Michigan Medical School, Ann Arbor, MI 48105
| | - Howard R. Petty
- Department of Ophthalmology and Visual Sciences, The University of Michigan Medical School, Ann Arbor, MI 48105
- Department of Microbiology and Immunology, The University of Michigan Medical School, Ann Arbor, MI 48105
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11
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Yuan M, Jordan F, McInnes IB, Harnett MM, Norman JE. Leukocytes are primed in peripheral blood for activation during term and preterm labour. Mol Hum Reprod 2009; 15:713-24. [PMID: 19628509 PMCID: PMC2762373 DOI: 10.1093/molehr/gap054] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
We hypothesized that the priming and activation of maternal leukocytes in peripheral blood is a key component of parturition, and that inappropriate preterm priming of leukocytes might initiate preterm labour and delivery. The purpose of this study was to characterize peripheral blood leukocyte activation during human term and preterm labour. We obtained blood samples from pregnant women at term and preterm, both in labour and not in labour. Leukocytes were characterized according to cell subtype and cell surface marker expression. Additionally, we quantified leukocyte cytokine mRNA production, migratory ability and reactive oxygen species production of neutrophils and macrophages. We found that both term and preterm labour were associated with an increase in monocyte and neutrophil proportion or number—neutrophil migratory ability and cell surface marker expression indicating activation. Messenger RNA expression of IL-1β and IL-8, MCP-1 and TLR-2 was also increased. We conclude that leukocytes in peripheral blood are primed in preparation for activation during term and preterm labour, and that this may contribute to the pathophysiological events of parturition. These data may lead to novel therapies and diagnostic tools for the prevention and/or diagnosis of preterm birth.
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Affiliation(s)
- M Yuan
- Centre for Reproductive Biology, The Queen's Medical Research Centre, University of Edinburgh, Edinburgh EH16 4TY, UK
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12
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Slaby O, Lebiedz D. Oscillatory NAD(P)H waves and calcium oscillations in neutrophils? A modeling study of feasibility. Biophys J 2009; 96:417-28. [PMID: 19167293 DOI: 10.1016/j.bpj.2008.09.044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 09/29/2008] [Indexed: 11/17/2022] Open
Abstract
The group of Howard Petty has claimed exotic metabolic wave phenomena together with mutually phase-coupled NAD(P)H- and calcium-oscillations in human neutrophils. At least parts of these phenomena are highly doubtful due to extensive failure of reproducibility by several other groups and hints that unreliable data from the Petty lab are involved in publications concerning circular calcium waves. The aim of our theoretical spatiotemporal modeling approach is to propose a possible and plausible biochemical mechanism which would, in principle, be able to explain metabolic oscillations and wave phenomena in neutrophils. Our modeling suggests the possibility of a calcium-controlled glucose influx as a driving force of metabolic oscillations and a potential role of polarized cell geometry and differential enzyme distribution for various NAD(P)H wave phenomena. The modeling results are supposed to stimulate further controversial discussions of such phenomena and potential mechanisms and experimental efforts to finally clarify the existence and biochemical basis of any kind of temporal and spatiotemporal patterns of calcium signals and metabolic dynamics in human neutrophils. Independent of Petty's observations, they present a general feasibility study of such phenomena in cells.
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13
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Kropf P, Baud D, Marshall SE, Munder M, Mosley A, Fuentes JM, Bangham CRM, Taylor GP, Herath S, Choi BS, Soler G, Teoh T, Modolell M, Müller I. Arginase activity mediates reversible T cell hyporesponsiveness in human pregnancy. Eur J Immunol 2007; 37:935-45. [PMID: 17330821 PMCID: PMC2699382 DOI: 10.1002/eji.200636542] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 11/15/2006] [Accepted: 02/01/2007] [Indexed: 11/24/2022]
Abstract
Complex regulation of T cell functions during pregnancy is required to ensure materno-fetal tolerance. Here we reveal a novel pathway for the temporary suppression of maternal T cell responses in uncomplicated human pregnancies. Our results show that arginase activity is significantly increased in the peripheral blood of pregnant women and remarkably high arginase activities are expressed in term placentae. High enzymatic activity results in high turnover of its substrate L-arginine and concomitant reduction of this amino acid in the microenvironment. Amino acid deprivation is emerging as a regulatory pathway of lymphocyte responses and we assessed the consequences of this enhanced arginase activity on T cell responses. Arginase-mediated L-arginine depletion induces down-regulation of CD3 zeta, the main signalling chain of the TCR, and functional T cell hyporesponsiveness. Importantly, this arginase-mediated T cell suppression was reversible, as inhibition of arginase activity or addition of exogenous L-arginine restored CD3 zeta chain expression and T cell proliferation. Thus, L-arginine metabolism constitutes a novel physiological mechanism contributing to the temporary suppression of the maternal immune response during human pregnancy.
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Affiliation(s)
- Pascale Kropf
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - David Baud
- Department of Obstetrics and Gynaecology, St. Mary's HospitalLondon, UK
| | - Sara E Marshall
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - Markus Munder
- Department of Hematology, Oncology, and Rheumatology, University Hospital HeidelbergHeidelberg, Germany
| | - Angelina Mosley
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - José M Fuentes
- Departamento de Bioquímica y Biología Molecular, E.U. Enfermería y T.O., Universidad de ExtremaduraCáceres, Spain
| | - Charles R M Bangham
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - Graham P Taylor
- Department of Genito-Urinary Medicine and Communicable Diseases, Imperial CollegeLondon, UK
| | - Shanti Herath
- Department of Veterinary Clinical Sciences, Royal Veterinary CollegeLondon, UK
| | - Beak-San Choi
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - Germán Soler
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de ExtremaduraCáceres, Spain
| | - Tg Teoh
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de ExtremaduraCáceres, Spain
| | - Manuel Modolell
- Department of Cellular Immunology, Max-Planck-Institute for ImmunobiologyFreiburg, Germany
| | - Ingrid Müller
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
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14
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Kummer U, Zobeley J, Brasen JC, Fahmy R, Kindzelskii AL, Petty AR, Clark AJ, Petty HR. Elevated glucose concentrations promote receptor-independent activation of adherent human neutrophils: an experimental and computational approach. Biophys J 2007; 92:2597-607. [PMID: 17237194 PMCID: PMC1864816 DOI: 10.1529/biophysj.106.086769] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neutrophil activation plays integral roles in host tissue damage and resistance to infectious diseases. As glucose uptake and NADPH availability are required for reactive oxygen metabolite production by neutrophils, we tested the hypothesis that pathological glucose levels (>or=12 mM) are sufficient to activate metabolism and reactive oxygen metabolite production in normal adherent neutrophils. We demonstrate that elevated glucose concentrations increase the neutrophil's metabolic oscillation frequency and hexose monophosphate shunt activity. In parallel, substantially increased rates of NO and superoxide formation were observed. However, these changes were not observed for sorbitol, a nonmetabolizable carbohydrate. Glucose transport appears to be important in this process as phloretin interferes with the glucose-specific receptor-independent activation of neutrophils. However, LY83583, an activator of glucose flux, promoted these changes at 1 mM glucose. The data suggest that at pathophysiologic concentrations, glucose uptake by mass action is sufficient to activate neutrophils, thus circumventing the normal receptor transduction mechanism. To enable us to mechanistically understand these dynamic metabolic changes, mathematical simulations were performed. A model for glycolysis in neutrophils was created. The results indicated that the frequency change in NAD(P)H oscillations can result from the activation of the hexose monophosphate shunt, which competes with glycolysis for glucose-6-phosphate. Experimental confirmation of these simulations was performed by measuring the effect of glucose concentrations on flavoprotein autofluorescence, an indicator of the rate of mitochondrial electron transport. Moreover, after prolonged exposure to elevated glucose levels, neutrophils return to a "nonactivated" phenotype and are refractile to immunologic stimulation. Our findings suggest that pathologic glucose levels promote the transient activation of neutrophils followed by the suppression of cell activity, which may contribute to nonspecific tissue damage and increased susceptibility to infections, respectively.
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Affiliation(s)
- Ursula Kummer
- Bioinformatics and Computational Biochemistry, EML Research, Heidelberg, Germany
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15
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Huang JB, Clark AJ, Petty HR. The hexosamine biosynthesis pathway negatively regulates IL-2 production by Jurkat T cells. Cell Immunol 2007; 245:1-6. [PMID: 17481598 PMCID: PMC3178408 DOI: 10.1016/j.cellimm.2007.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 03/21/2007] [Accepted: 03/26/2007] [Indexed: 10/23/2022]
Abstract
To test the hypothesis that the hexosamine biosynthesis pathway (HBP) affects cytokine production, we studied IL-2 production by Jurkat cells in response to PHA. We found that the HBP activator glucosamine (GlcN), but not glucose (Glc), dose-dependently reduced IL-2 production. Importantly, GlcN blocked trafficking of a GFP-NFAT chimeric protein to the nucleus of stimulated transfectants. Not surprisingly, changes in O-GlcNAc protein modifications were noted during cell activation with and without GlcN addition. These findings could not be explained by some non-specific change in cell metabolism because ATP concentrations did not significantly change. We speculate that HBP-active compounds may contribute to patient care in certain inflammatory and autoimmune diseases.
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Affiliation(s)
- Ji-Biao Huang
- Department of Ophthalmology and Visual Sciences, The University of Michigan Medical School, 1000 Wall Street, Ann Arbor, MI 48105, USA
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16
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Kindzelskii AL, Elner VM, Elner SG, Yang D, Hughes BA, Petty HR. Toll-like receptor 4 (TLR4) of retinal pigment epithelial cells participates in transmembrane signaling in response to photoreceptor outer segments. J Gen Physiol 2004; 124:139-49. [PMID: 15277575 PMCID: PMC2229626 DOI: 10.1085/jgp.200409062] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Accepted: 06/17/2004] [Indexed: 11/23/2022] Open
Abstract
Retinal pigment epithelial (RPE) cells mediate the recognition and clearance of effete photoreceptor outer segments (POS), a process central to the maintenance of normal vision. Given the emerging importance of Toll-like receptors (TLRs) in transmembrane signaling in response to invading pathogens as well as endogenous substances, we hypothesized that TLRs are associated with RPE cell management of POS. TLR4 clusters on human RPE cells in response to human, but not bovine, POS. However, TLR4 clustering could be inhibited by saturating concentrations of an inhibitory anti-TLR4 mAb. Furthermore, human POS binding to human RPE cells elicited transmembrane metabolic and calcium signals within RPE cells, which could be blocked by saturating doses of an inhibitory anti-TLR4 mAb. However, the heterologous combination of bovine POS and human RPE did not trigger these signals. The pattern recognition receptor CD36 collected at the POS-RPE cell interface for both homologous and heterologous samples, but human TLR4 only collected at the human POS-human RPE cell interface. Kinetic experiments of human POS binding to human RPE cells revealed that CD36 arrives at the POS-RPE interface followed by TLR4 accumulation within 2 min. Metabolic and calcium signals immediately follow. Similarly, the production of reactive oxygen metabolites (ROMs) was observed for the homologous human system, but not the heterologous bovine POS-human RPE cell system. As (a) the bovine POS/human RPE combination did not elicit TLR4 accumulation, RPE signaling, or ROM release, (b) TLR4 arrives at the POS-RPE cell interface just before signaling, (c) TLR4 blockade with an inhibitory anti-TLR4 mAb inhibited TLR4 clustering, signaling, and ROM release in the human POS-human RPE system, and (d) TLR4 demonstrates similar clustering and signaling responses to POS in confluent RPE monolayers, we suggest that TLR4 of RPE cells participates in transmembrane signaling events that contribute to the management of human POS.
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Affiliation(s)
- Andrei L Kindzelskii
- Department of Ophthalmology and Visual Sciences, The University of Michigan Medical School, Ann Arbor, MI 48105, USA
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17
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Kindzelskii A, Petty HR. Fluorescence spectroscopic detection of mitochondrial flavoprotein redox oscillations and transient reduction of the NADPH oxidase-associated flavoprotein in leukocytes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2003; 33:291-9. [PMID: 14574524 DOI: 10.1007/s00249-003-0361-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Accepted: 09/27/2003] [Indexed: 10/26/2022]
Abstract
Steady-state and time-resolved fluorescence spectroscopy and fluorescence microscopy of leukocyte flavoproteins have been performed. Both living human peripheral blood monocytes and neutrophils have been utilized as experimental models, as the former relies much more heavily on mitochondrial metabolism for energy production than the latter. We confirm previous studies indicating that cellular flavoproteins absorb at 460 nm and emit at 530 nm, very similar to that of the FAD moiety. Furthermore, the emission properties of intracellular flavoproteins were altered by the metabolic inhibitors rotenone, antimycin A, azide, cyanide, DNP (2,4-dinitrophenol), and FCCP [carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone]. Kinetic studies revealed flavoprotein emission oscillations in both monocytes and neutrophils. The flavoprotein intensity oscillations correlated with the physiological status of the cell and the nature of membrane receptor ligation. Microscopy revealed the presence of flavoprotein fluorescence in association with the plasma membrane, intracellular granules and distributed throughout the cytoplasm, presumably within mitochondria. Metabolic inhibitors such as cyanide suggest that the plasma membrane and granular components are cyanide-insensitive and therefore are likely associated with the flavoprotein component of the NADPH oxidase, which is located in these two compartments. This interpretation was found to be consistent with structural localization of the NADPH oxidase using an antibody molecule specific for this protein. Using peripheral blood neutrophils, which display less active mitochondria, and time-resolved emission spectroscopy, we show that the NADPH oxidase-associated flavoprotein undergoes a periodic transient reduction of about 54+/-2 ms in living cells. This finding is consistent with prior studies indicating that propagating substrate (NADPH) waves periodically promote electron transport across the NADPH oxidase.
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Affiliation(s)
- Andrei Kindzelskii
- Department of Ophthalmology and Visual Science, The University of Michigan School of Medicine, 1000 Wall Street, Ann Arbor, MI 48105, USA
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