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  1. Article: A dual neutrophil-T cell purification procedure and methodological considerations in studying the effects of estrogen on human Th17 cell differentiation

    Xiu, Fangming / Zubair Sabz Ali / Nades Palaniyar / Neil Sweezey

    Journal of immunological methods. 2019 Jan. 02,

    2019  

    Abstract: New procedures are required to optimize the use of blood samples to study different cell types. The purification of neutrophils and T cells from the same blood sample is not commonly described. We have previously used PolymorphPrep™ (P) or LymphoPrep™ (L) ...

    Abstract New procedures are required to optimize the use of blood samples to study different cell types. The purification of neutrophils and T cells from the same blood sample is not commonly described. We have previously used PolymorphPrep™ (P) or LymphoPrep™ (L) for purifying neutrophils or T cells, respectively. In this study, we describe a new method for purifying both of these cells using P and L from the same sample, and methodological considerations required to obtain consistent Th17 differentiation results. For T cell studies, we first isolated mononuclear cells from peripheral blood of healthy humans using either P alone, L alone or sequential isolation with P and then L (P + L). CD3+ lymphocytes comprise up to 73% of peripheral blood mononuclear cells (PBMCs) obtained by sequential isolation, with 29% and 36% for P and L, respectively. T lymphocyte subsets, Th1, Th17 or double-positive (Th17/1), were then amplified. Four days of amplification culture after isolation by P alone led to over-expression of Th17/1 cells and of Th17 cells in comparison to cells isolated by L or by sequential P + L. Th17/1 cells comprised 11.0 ± 6.8% (P alone) vs 1.2 ± 0.28% (L alone) vs 0.45 ± 0.11% (P + L) and Th17 cells comprised 2.8 ± 0.4% (P alone) 0.88 ± 0.15% (L alone) vs 0.86 ± 0.14% (P + L). As the second step, we examined T cell purification and differentiation. A higher purity of 97.1 ± 0.44% naïve CD4+ T cell was reached after P + L followed by immunomagnetic bead sorting in comparison to 70 ± 9.3% (L) vs 21.0 ± 8.5% (P). These cells grew well in the density range of 25, 000 to 100, 000 cells per well in 96-well plates during Th17 cell differentiation; higher or lower cell density did not support Th17 cell differentiation. Lastly, to investigate the effect of estrogen on Th17 cell differentiation, serum-free AIM V medium without phenol red was chosen to minimize the hormonal effects of the medium. We found that exogenous estrogen (1 nM) inhibited Th17 cell differentiation in this medium. Taken together, we devised a method to isolate both neutrophils and T cells from the same blood sample and show that high PBMC purity, selected culture medium and an optimal cell density of the initial cell culture produced the most robust and consistent results for Th17 differentiation.
    Keywords CD4-positive T-lymphocytes ; blood sampling ; cell culture ; cell differentiation ; culture media ; estrogens ; humans ; neutrophils ; phenolsulfonphthalein
    Language English
    Dates of publication 2019-0102
    Size p. .
    Publishing place Elsevier B.V.
    Document type Article
    Note Pre-press version
    ZDB-ID 120142-6
    ISSN 1872-7905 ; 0022-1759
    ISSN (online) 1872-7905
    ISSN 0022-1759
    DOI 10.1016/j.jim.2019.01.002
    Database NAL-Catalogue (AGRICOLA)

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  2. Article: Surfactant Protein D Regulates Caspase-8-mediated Cascade of the Intrinsic Pathway of Apoptosis While Promoting Bleb Formation

    Djiadeu, Pascal / Nicole Farmakovski / Dhia Azzouz / Lakshmi P. Kotra / Neil Sweezey / Nades Palaniyar

    Molecular Immunology. 2017,

    2017  

    Abstract: Surfactant-associated protein D (SP-D) is a soluble innate immune collectin present on many mucosal surfaces. We recently showed that SP-D suppresses the extrinsic pathway of apoptosis by downregulating caspase-8 activation. However, the effects of SP-D ... ...

    Abstract Surfactant-associated protein D (SP-D) is a soluble innate immune collectin present on many mucosal surfaces. We recently showed that SP-D suppresses the extrinsic pathway of apoptosis by downregulating caspase-8 activation. However, the effects of SP-D on the intrinsic pathway of apoptosis are not clearly understood. In the intrinsic pathway, cytochrome c is released by mitochondria into the cytoplasm. Oxidation of cytochrome c by cytochrome c oxidase activates the apoptosome and caspase-9 cascade. Both caspase-8- and caspase-9-mediated branches are activated in the intrinsic pathway of apoptosis; however, little is known about the relevance of the caspase-8 pathway in this context. Here we studied the effects of SP-D on different branches of the intrinsic pathway of apoptosis using UV-irradiated Jurkat T-cells. We found that SP-D does not inhibit the caspase-9 branch of apoptosis and the relevance of the caspase-8-related branch became apparent when the caspase-9 pathway was inhibited by blocking cytochrome c oxidase. Under these conditions, SP-D reduces the activation of caspase-8, executioner caspase-3 and exposure of phosphatidylserine (PS) on the membranes of dying cells. By contrast, SP-D increases the formation of nuclear and membrane blebs. Inhibition of caspase-8 confirms the effect of SP-D is unique to the caspase-8 pathway. Overall, SP-D suppresses certain aspects of the intrinsic pathway of apoptosis via reduction of caspase-8 activation and PS flipping while at the same time increasing membrane and nuclear bleb formation. This novel regulatory aspect of SP-D could help to regulate intrinsic pathway of apoptosis to promote effective blebbing and breakdown of dying cells.
    Keywords T-lymphocytes ; apoptosis ; caspase-3 ; caspase-8 ; caspase-9 ; cytochrome c ; cytochrome-c oxidase ; mitochondria ; mucosa ; oxidation ; phosphatidylserines ; surfactants ; ultraviolet radiation
    Language English
    Size p. .
    Publishing place Elsevier Ltd
    Document type Article
    Note Pre-press version
    ZDB-ID 424427-8
    ISSN 1872-9142 ; 0161-5890
    ISSN (online) 1872-9142
    ISSN 0161-5890
    DOI 10.1016/j.molimm.2017.10.016
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: Regulating NETosis

    Meraj A. Khan / Lijy M. Philip / Guillaume Cheung / Shawn Vadakepeedika / Hartmut Grasemann / Neil Sweezey / Nades Palaniyar

    Frontiers in Medicine, Vol

    Increasing pH Promotes NADPH Oxidase-Dependent NETosis

    2018  Volume 5

    Abstract: Neutrophils migrating from the blood (pH 7.35–7.45) into the surrounding tissues encounter changes in extracellular pH (pHe) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H+ ions reducing the intracellular pH ...

    Abstract Neutrophils migrating from the blood (pH 7.35–7.45) into the surrounding tissues encounter changes in extracellular pH (pHe) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units) increased pHi of both activated and resting neutrophils within 10–20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3− ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar bicarbonate solution. For that reason, regulating NETosis by pH with specific buffers such as THAM could be more effective than bicarbonate in managing NET-related diseases.
    Keywords neutrophil extracellular trap formation ; pH ; spontaneous NETosis ; NADPH-dependent NETosis ; lipopolysaccharide-induced NETosis ; Gram-negative bacteria-induced NETosis ; Medicine (General) ; R5-920
    Subject code 572
    Language English
    Publishing date 2018-02-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: JNK Activation Turns on LPS- and Gram-Negative Bacteria-Induced NADPH Oxidase-Dependent Suicidal NETosis

    Meraj A. Khan / Armin Farahvash / David N. Douda / Johann-Christoph Licht / Hartmut Grasemann / Neil Sweezey / Nades Palaniyar

    Scientific Reports, Vol 7, Iss 1, Pp 1-

    2017  Volume 16

    Abstract: Abstract Neutrophils cast neutrophil extracellular traps (NETs) to ensnare microbial pathogens. Nevertheless, the molecular rheostats that regulate NETosis in response to bacteria are not clearly established. We hypothesized that stress-activated protein ...

    Abstract Abstract Neutrophils cast neutrophil extracellular traps (NETs) to ensnare microbial pathogens. Nevertheless, the molecular rheostats that regulate NETosis in response to bacteria are not clearly established. We hypothesized that stress-activated protein kinase or c-Jun N-terminal Kinase (SAPK/JNK) is a molecular switch that turns on NETosis in response to increasing concentrations of lipopolysaccharide (LPS)- and Gram-negative bacteria. Here we show that Escherichia coli LPS (0111:B4; 10–25 μg/ml), but not phorbol myristate acetate (PMA), activates JNK in human neutrophils in a dose-dependent manner. JNK inhibitors SP600125 and TCSJNK6o, and a TLR4 inhibitor TAK242 suppress reactive oxygen species production and NETosis in LPS-, but not PMA-treated neutrophils. Diphenyleneiodonium suppresses LPS-induced NETosis, confirming that endotoxin induces NADPH oxidase-dependent NETosis. Immunoblots, Sytox Green assays, and confocal microscopy of cleaved caspase-3 and nuclear morphology show that JNK inhibition does not induce apoptosis in LPS-stimulated neutrophils. JNK inhibition also suppresses NETosis induced by two typical Gram-negative bacteria, E. coli and Pseudomonas aeruginosa. Therefore, we propose that neutrophils use a TLR4-dependent, JNK-mediated molecular sensing mechanism to initiate NADPH oxidase-dependent suicidal NETosis in response to increasing concentrations of LPS, and Gram-negative bacteria. The LPS-TLR4-JNK activation axis determines the fate of these cells: to be or not to be NETotic neutrophils.
    Keywords Medicine ; R ; Science ; Q
    Subject code 630
    Language English
    Publishing date 2017-06-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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