Functional analysis of monocyte MHC class II compartments

Bunbury, Allyson; Potolicchio, Ilaria; Maitra, Radhashree; Santambrogio, Laura

doi:10.1096/fj.08-109439

Cited by 16 publications

(11 citation statements)

References 38 publications

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“…Five reagents, namely myeloperoxidase, lysozyme, CD34, CD117 and CD163, are commonly used for diagnostic purposes. Myeloperoxidase, which is present in the primary (azurophilic) granules of neutrophils and their precursors, is present at low level in circulating monocytes 20 and may be elicited by immunohistochemistry 21 . Perhaps, then, it is not surprising that myeloperoxidase immunostaining was positive in 42% of our cases of acute monoblastic/monocytic leukemia.…”

Section: Discussionmentioning

confidence: 83%

Use of classic and novel immunohistochemical markers in the diagnosis of cutaneous myeloid sarcoma

Amador-Ortiz

Hurley

Ghahramani

et al. 2011

Journal of Cutaneous Pathology

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Cutaneous myeloid sarcoma is often challenging to diagnose based solely upon histopathological features. Although immunohistochemistry can aid in its diagnosis, specific markers have not been clearly identified. We evaluated the utility of immunohistochemical markers in 57 cutaneous myeloid sarcoma cases. In addition to classical markers (CD117, CD163, CD34, myeloperoxidase and lysozyme), we used CD33 and CD14, recently described markers in paraffin-embedded tissue samples, and Kruppel-like factor 4 (KLF-4), a novel monocytic marker. Our results show that lysozyme was expressed in 91%, CD33 in 60%, myeloperoxidase in 54%, CD34 in 39% and CD117 in 36% of cases. An antibody panel that included lysozyme, CD117 and CD33 identified all cases. The monocytic markers CD14, KLF-4 and CD163 were expressed in 60, 58 and 40% of all cases, respectively. CD14 and KLF-4 expression was significantly more common in cases with monocytic differentiation. CD14 is the single most sensitive and specific marker for monocytic differentiation (79 and 80%). Although KLF-4 in isolation is relatively insensitive (50 and 87%), it enhances sensitivity in detecting monocytic cutaneous myeloid sarcoma when combined with CD14. Our results indicate that in addition to classical immunohistochemical markers, targeted use of newer antibodies, including CD33, CD14 and KLF-4 is useful in the diagnosis of cutaneous myeloid sarcoma and in the detection of monocytic differentiation.

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Section: Discussionmentioning

confidence: 83%

Use of classic and novel immunohistochemical markers in the diagnosis of cutaneous myeloid sarcoma

Amador-Ortiz

Hurley

Ghahramani

et al. 2011

Journal of Cutaneous Pathology

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“…Critical to innate immune function is the constitutive release [22], [23] from macrophages of the lysosomal enzyme β-hexosaminidase [24]. To assess the effects of culture conditions on this macrophage function, we quantified both secreted and intracellular amounts of β-hexosaminidase in PMA-differentiated THP-1 cells cultured in 18% O 2 versus 5% O 2 in the absence or presence of 2-ME and serum.…”

Section: Resultsmentioning

confidence: 99%

Oxygen Tension Modulates Differentiation and Primary Macrophage Functions in the Human Monocytic THP-1 Cell Line

2013

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The human THP-1 cell line is widely used as an in vitro model system for studying macrophage differentiation and function. Conventional culture conditions for these cells consist of ambient oxygen pressure (∼20% v/v) and medium supplemented with the thiol 2-mercaptoethanol (2-ME) and serum. In consideration of the redox activities of O2 and 2-ME, and the extensive experimental evidence supporting a role for reactive oxygen species (ROS) in the differentiation and function of macrophages, we addressed the question of whether culturing THP-1 cells under a more physiologically relevant oxygen tension (5% O2) in the absence of 2-ME and serum would alter THP-1 cell physiology. Comparisons of cultures maintained in 18% O2 versus 5% O2 indicated that reducing oxygen tension had no effect on the proliferation of undifferentiated THP-1 cells. However, decreasing the oxygen tension to 5% O2 significantly increased the rate of phorbol ester-induced differentiation of THP-1 cells into macrophage-like cells as well as the metabolic activity of both undifferentiated and PMA-differentiated THP-1 cells. Removal of both 2-ME and serum from the medium decreased the proliferation of undifferentiated THP-1 cells but increased metabolic activity and the rate of differentiation under either oxygen tension. In differentiated THP-1 cells, lowering the oxygen tension to 5% O2 decreased phagocytic activity, the constitutive release of β-hexosaminidase and LPS-induced NF-κB activation but enhanced LPS-stimulated release of cytokines. Collectively, these data demonstrate that oxygen tension influences THP-1 cell differentiation and primary macrophage functions, and suggest that culturing these cells under tightly regulated oxygen tension in the absence of exogenous reducing agent and serum is likely to provide a physiologically relevant baseline from which to study the role of the local redox environment in regulating THP-1 cell physiology.

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“…The enrichment of LAMP-1 and actin within the exosome pool observed with longer ATP stimulation suggests that plasma membrane-associated proteins are trafficked into endosomes during the early phase of P2X7 activation, incorporated into the ILV of MVBs, and then secreted as exosomes following MVB exocytosis. Recent studies have indicated that both MHCII and LAMP-1 associated with secretory lysosomes can be rapidly incorporated into the plasma membrane of human monocytes in response to Ca 2+ ionophore treatment (46). …”

Section: Discussionmentioning

confidence: 99%

P2X7 Receptor-Stimulated Secretion of MHC Class II-Containing Exosomes Requires the ASC/NLRP3 Inflammasome but Is Independent of Caspase-1

Qu¹,

Ramachandra²,

Mohr

et al. 2009

The Journal of Immunology

141

129

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We recently reported that P2X7 receptor (P2X7R)-induced activation of caspase-1 inflammasomes is accompanied by release of MHC class II (MHC-II) protein into extracellular compartments during brief stimulation of murine macrophages with ATP. Here we demonstrate that MHC-II containing membranes released from macrophages or dendritic cells (DCs) in response to P2X7R stimulation comprise two pools of vesicles with distinct biogenesis: one pool comprises 100-to 600-nm microvesicles derived from direct budding of the plasma membrane, while the second pool is composed of 50-to 80-nm exosomes released from multivesicular bodies. ATPstimulated release of MHC-II in these membrane fractions is observed within 15 min and results in the export of ϳ15% of the total MHC-II pool within 90 min. ATP did not stimulate MHC-II release in macrophages from P2X7R knockout mice. The inflammasome regulatory proteins, ASC (apoptosis-associated speck-like protein containing a caspase-recruitment domain) and NLRP3 (NLR family, pyrin domain containing 3), which are essential for caspase-1 activation, were also required for the P2X7R-regulated release of the exosome but not the microvesicle MHC-II pool. Treatment of bone marrow-derived macrophages with YVAD-cmk, a peptide inhibitor of caspase-1, also abrogated P2X7R-dependent MHC-II secretion. Surprisingly, however, MHC-II release in response to ATP was intact in caspase-1 ؊/؊ macrophages. The inhibitory actions of YVAD-cmk were mimicked by the pan-caspase inhibitor zVAD-fmk and the serine protease inhibitor TPCK, but not the caspase-3 inhibitor DEVD-cho. These data suggest that the ASC/NLRP3 inflammasome complexes assembled in response to P2X7R activation involve protease effector(s) in addition to caspase-1, and that these proteases may play important roles in regulating the membrane trafficking pathways that control biogenesis and release of MHC-II-containing exosomes. The Journal of Immunology, 2009, 182: 5052-5062. S timulation of P2X7 purinergic receptors (P2X7R)3 triggers the rapid assembly of inflammasome signaling complexes (1), which include ASC (apoptosis-associated speck-like protein containing a caspase-recruitment domain) (2) and NLRP3 (NLR family, pyrin domain containing 3; formerly Nalp3 or cyropyrin) (3); these complexes act as signaling platforms to drive the proteolytic activation of caspase-1 and maturation of IL-1␤. In a previous study of the mechanisms underlying nonclassical IL-␤ secretion stimulated by activation of P2X7R in murine macrophages, we observed that ATP-induced caspase-1 activation and IL-1␤ release were temporally correlated with a rapid and robust secretion of MHC class II (MHC-II) protein (4). That the ATPtriggered MHC-II export was greatly increased by LPS priming and was attenuated by the YVAD caspase-1 inhibitor suggested the intriguing possibility that caspase-1 inflammasomes play additional roles in the biogenesis and trafficking of MHC-II-enriched membrane compartments. Although rapid perturbation of ion homeostasis is the best characterized cellu...

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Functional analysis of monocyte MHC class II compartments

Cited by 16 publications

References 38 publications

Use of classic and novel immunohistochemical markers in the diagnosis of cutaneous myeloid sarcoma

Use of classic and novel immunohistochemical markers in the diagnosis of cutaneous myeloid sarcoma

Oxygen Tension Modulates Differentiation and Primary Macrophage Functions in the Human Monocytic THP-1 Cell Line

P2X7 Receptor-Stimulated Secretion of MHC Class II-Containing Exosomes Requires the ASC/NLRP3 Inflammasome but Is Independent of Caspase-1

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