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Burgener SS, Baumann M, Basilico P, Remold-O'Donnell E, Touw IP, Benarafa C. Myeloid conditional deletion and transgenic models reveal a threshold for the neutrophil survival factor Serpinb1. Biol Chem 2017; 397:897-905. [PMID: 27107834 DOI: 10.1515/hsz-2016-0132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/20/2016] [Indexed: 11/15/2022]
Abstract
Serpinb1 is an inhibitor of neutrophil granule serine proteases cathepsin G, proteinase-3 and elastase. One of its core physiological functions is to protect neutrophils from granule protease-mediated cell death. Mice lacking Serpinb1a (Sb1a-/-), its mouse ortholog, have reduced bone marrow neutrophil numbers due to cell death mediated by cathepsin G and the mice show increased susceptibility to lung infections. Here, we show that conditional deletion of Serpinb1a using the Lyz2-cre and Cebpa-cre knock-in mice effectively leads to recombination-mediated deletion in neutrophils but protein-null neutrophils were only obtained using the latter recombinase-expressing strain. Absence of Serpinb1a protein in neutrophils caused neutropenia and increased granule permeabilization-induced cell death. We then generated transgenic mice expressing human Serpinb1 in neutrophils under the human MRP8 (S100A8) promoter. Serpinb1a expression levels in founder lines correlated positively with increased neutrophil survival when crossed with Sb1a-/- mice, which had their defective neutrophil phenotype rescued in the higher expressing transgenic line. Using new conditional and transgenic mouse models, our study demonstrates the presence of a relatively low Serpinb1a protein threshold in neutrophils that is required for sustained survival. These models will also be helpful in delineating recently described functions of Serpinb1 in metabolism and cancer.
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El Ouaamari A, Dirice E, Gedeon N, Hu J, Zhou JY, Shirakawa J, Hou L, Goodman J, Karampelias C, Qiang G, Boucher J, Martinez R, Gritsenko MA, De Jesus DF, Kahraman S, Bhatt S, Smith RD, Beer HD, Jungtrakoon P, Gong Y, Goldfine AB, Liew CW, Doria A, Andersson O, Qian WJ, Remold-O'Donnell E, Kulkarni RN. SerpinB1 Promotes Pancreatic β Cell Proliferation. Cell Metab 2016; 23:194-205. [PMID: 26701651 PMCID: PMC4715773 DOI: 10.1016/j.cmet.2015.12.001] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 10/20/2015] [Accepted: 11/30/2015] [Indexed: 01/09/2023]
Abstract
Although compensatory islet hyperplasia in response to insulin resistance is a recognized feature in diabetes, the factor(s) that promote β cell proliferation have been elusive. We previously reported that the liver is a source for such factors in the liver insulin receptor knockout (LIRKO) mouse, an insulin resistance model that manifests islet hyperplasia. Using proteomics we show that serpinB1, a protease inhibitor, which is abundant in the hepatocyte secretome and sera derived from LIRKO mice, is the liver-derived secretory protein that regulates β cell proliferation in humans, mice, and zebrafish. Small-molecule compounds, that partially mimic serpinB1 effects of inhibiting elastase activity, enhanced proliferation of β cells, and mice lacking serpinB1 exhibit attenuated β cell compensation in response to insulin resistance. Finally, SerpinB1 treatment of islets modulated proteins in growth/survival pathways. Together, these data implicate serpinB1 as an endogenous protein that can potentially be harnessed to enhance functional β cell mass in patients with diabetes.
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Affiliation(s)
- Abdelfattah El Ouaamari
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Ercument Dirice
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Nicholas Gedeon
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Jiang Hu
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Jian-Ying Zhou
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Jun Shirakawa
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Lifei Hou
- Program in Cellular and Molecular Medicine at Boston Children's Hospital, 3 Blackfan Circle, Boston, MA 02215, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02215, USA
| | - Jessica Goodman
- Program in Cellular and Molecular Medicine at Boston Children's Hospital, 3 Blackfan Circle, Boston, MA 02215, USA
| | - Christos Karampelias
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 17177 Stockholm, Sweden
| | - Guifeng Qiang
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Jeremie Boucher
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA; Cardiovascular and Metabolic Diseases iMed, AstraZeneca R&D, 431 83 Mölndal, Sweden
| | - Rachael Martinez
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Marina A Gritsenko
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Dario F De Jesus
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Sevim Kahraman
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Shweta Bhatt
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA
| | - Richard D Smith
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Hans-Dietmar Beer
- University Hospital Zurich, Department of Dermatology, 8006 Zurich, Switzerland
| | - Prapaporn Jungtrakoon
- Section on Genetics and Epidemiology, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Yanping Gong
- Program in Cellular and Molecular Medicine at Boston Children's Hospital, 3 Blackfan Circle, Boston, MA 02215, USA
| | - Allison B Goldfine
- Section on Clinical Research, Joslin Diabetes Center and Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - Chong Wee Liew
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Alessandro Doria
- Section on Genetics and Epidemiology, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Olov Andersson
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, 17177 Stockholm, Sweden
| | - Wei-Jun Qian
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Eileen Remold-O'Donnell
- Program in Cellular and Molecular Medicine at Boston Children's Hospital, 3 Blackfan Circle, Boston, MA 02215, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02215, USA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02215, USA
| | - Rohit N Kulkarni
- Islet Cell and Regenerative Medicine, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02215, USA.
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Hou L, Cooley J, Swanson R, Ong PC, Pike RN, Bogyo M, Olson ST, Remold-O'Donnell E. The protease cathepsin L regulates Th17 cell differentiation. J Autoimmun 2015; 65:56-63. [PMID: 26343333 DOI: 10.1016/j.jaut.2015.08.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 08/11/2015] [Accepted: 08/14/2015] [Indexed: 01/14/2023]
Abstract
Previously we reported that IL-17(+) T cells, primarily IL-17(+) γδ cells, are increased in mice lacking the protease inhibitor serpinB1 (serpinb1(-/-) mice). Here we show that serpinB1-deficient CD4 cells exhibit a cell-autonomous and selective deficiency in suppressing T helper 17 (Th17) cell differentiation. This suggested an opposing role for one or more protease in promoting Th17 differentiation. We found that several SerpinB1-inhibitable cysteine cathepsins are induced in Th17 cells, most prominently cathepsin L (catL); this was verified by peptidase assays, active site labeling and Western blots. Moreover, Th17 differentiation was suppressed by both broad cathepsin inhibitors and catL selective inhibitors. CatL is present in Th17 cells as single chain (SC)- and two-chain (TC)-forms. Inhibiting asparagine endopeptidase (AEP) blocked conversion of SC-catL to TC-catL and increased generation of serpinb1(-/-) Th17 cells, but not wild-type Th17 cells. These findings suggest that SC-catL is biologically active in promoting Th17 generation and is counter-regulated by serpinB1 and secondarily by AEP. Thus, in addition to regulation by cytokines and transcription factors, differentiation of CD4 cells to Th17 cells is actively regulated by a catL-serpinB1-AEP module. Targeting this protease regulatory module could be an approach to treating Th17 cell-driven autoimmune disorders.
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Affiliation(s)
- Lifei Hou
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
| | - Jessica Cooley
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Richard Swanson
- Department of Periodontics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Poh Chee Ong
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Robert N Pike
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA 94305, USA
| | - Steven T Olson
- Department of Periodontics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Eileen Remold-O'Donnell
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
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Loison F, Zhu H, Karatepe K, Kasorn A, Liu P, Ye K, Zhou J, Cao S, Gong H, Jenne DE, Remold-O'Donnell E, Xu Y, Luo HR. Proteinase 3-dependent caspase-3 cleavage modulates neutrophil death and inflammation. J Clin Invest 2014; 124:4445-58. [PMID: 25180606 DOI: 10.1172/jci76246] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 07/24/2014] [Indexed: 12/11/2022] Open
Abstract
Caspase-3-mediated spontaneous death in neutrophils is a prototype of programmed cell death and is critical for modulating physiopathological inflammatory responses; however, the underlying regulatory pathways remain ill defined. Here we determined that in aging neutrophils, the cleavage and activation of caspase-3 is independent of the canonical caspase-8- or caspase-9-mediated pathway. Instead, caspase-3 activation was mediated by serine protease proteinase 3 (PR3), which is present in the cytosol of aging neutrophils. Specifically, PR3 cleaved procaspase-3 at a site upstream of the canonical caspase-9 cleavage site. In mature neutrophils, PR3 was sequestered in granules and released during aging via lysosomal membrane permeabilization (LMP), leading to procaspase-3 cleavage and apoptosis. Pharmacological inhibition or knockdown of PR3 delayed neutrophil death in vitro and consistently delayed neutrophil death and augmented neutrophil accumulation at sites of inflammation in a murine model of peritonitis. Adoptive transfer of both WT and PR3-deficient neutrophils revealed that the delayed death of neutrophils lacking PR3 is due to an altered intrinsic apoptosis/survival pathway, rather than the inflammatory microenvironment. The presence of the suicide protease inhibitor SERPINB1 counterbalanced the protease activity of PR3 in aging neutrophils, and deletion of Serpinb1 accelerated neutrophil death. Taken together, our results reveal that PR3-mediated caspase-3 activation controls neutrophil spontaneous death.
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Abstract
SerpinB1 is an endogenous inhibitor of serine proteases recognized for its anti-inflammatory and host-protective properties. Although loss of serpinB1 in mice does not result in gross immune deregulation, serpinb1a(-/-) mice display increased mortality and inflammation-associated morbidity upon challenge with influenza virus. Here, we show that IL-17A(+) γδ and CD4(+) Th17 cells are already expanded in the lungs of serpinb1a(-/-) mice at steady-state. Both γδ and αβ(+) CD4(+) CCR6(+) T cells isolated from the lungs of naive serpinb1a(-/-) mice displayed a skewed transcriptional profile relative to WT cells, including increased Th17 signature transcripts [Il17a, l17f, and Rorc (RORγt)] and decreased Th1 signature transcripts [Ifng, Cxcr3, and Tbx21 (T-bet)] in γδ T cells. In addition to the lung, IL-17A(+) γδ and CD4(+) Th17 cells were increased in the spleen of naive serpinb1a(-/-) mice, despite normal αβ and γδ T cell development in the thymus. Within the γδ T cell compartment, loss of serpinb1a prompted selective expansion of Vγ4(+) and Vγ6/Vδ1(+) cells, which also displayed elevated expression of the proliferating cell nuclear antigen, Ki-67, and IL-17A. Given that serpinb1a is preferentially expressed in WT IL-17A(+) γδ and CD4(+) Th17 cell subsets vis-à-vis other T cell lineages, our findings reveal a novel function of serpinB1 in limiting untoward expansion of lymphocytes with a Th17 phenotype.
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Stolley JM, Gong D, Farley K, Zhao P, Cooley J, Crouch EC, Benarafa C, Remold-O'Donnell E. Increased surfactant protein D fails to improve bacterial clearance and inflammation in serpinB1-/- mice. Am J Respir Cell Mol Biol 2012; 47:792-9. [PMID: 23024061 DOI: 10.1165/rcmb.2012-0145oc] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Previously, we described the protective role of the neutrophil serine protease inhibitor serpinB1 in preventing early mortality of Pseudomonas aeruginosa lung infection by fostering bacterial clearance and limiting inflammatory cytokines and proteolytic damage. Surfactant protein D (SP-D), which maintains the antiinflammatory pulmonary environment and mediates bacterial removal, was degraded in infected serpinB1-deficient mice. Based on the hypothesis that increased SP-D would rescue or mitigate the pathological effects of serpinB1 deletion, we generated two serpinB1(-/-) lines overexpressing lung-specific rat SP-D and inoculated the mice with P. aeruginosa. Contrary to predictions, bacterial counts in the lungs of SP-D(low)serpinB1(-/-) and SP-D(high) serpinB1(-/-) mice were 4 logs higher than wild-type and not different from serpinB1(-/-) mice. SP-D overexpression also failed to mitigate inflammation (TNF-α), lung injury (free protein, albumin), or excess neutrophil death (free myeloperoxidase, elastase). These pathological markers were higher for infected SP-D(high)serpinB1(-/-) mice than for serpinB1(-/-) mice, although the differences were not significant after controlling for multiple comparisons. The failure of transgenic SP-D to rescue antibacterial defense of serpinB1-deficient mice occurred despite 5-fold or 20-fold increased expression levels, largely normal structure, and dose-dependent bacteria-aggregating activity. SP-D of infected wild-type mice was intact in 43-kD monomers by reducing SDS-PAGE. By contrast, proteolytic fragments of 35, 17, and 8 kD were found in infected SP-D(low)serpinB1(-/-), SP-D(high) serpinB1(-/-) mice, and serpinB1(-/-) mice. Thus, although therapies to increase lung concentration of SP-D may have beneficial applications, the findings suggest that therapy with SP-D may not be beneficial for lung inflammation or infection if the underlying clinical condition includes excess proteolysis.
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Affiliation(s)
- J Michael Stolley
- Immune Disease Institute, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115, USA
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Farley K, Stolley JM, Zhao P, Cooley J, Remold-O'Donnell E. A serpinB1 regulatory mechanism is essential for restricting neutrophil extracellular trap generation. J Immunol 2012; 189:4574-81. [PMID: 23002442 DOI: 10.4049/jimmunol.1201167] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
NETosis (neutrophil extracellular trap [NET] generation), a programmed death pathway initiated in mature neutrophils by pathogens and inflammatory mediators, can be a protective process that sequesters microbes and prevents spread of infection, but it can also be a pathological process that causes inflammation and serious tissue injury. Little is known about the regulatory mechanism. Previously, we demonstrated that serpinb1-deficient mice are highly susceptible to pulmonary bacterial and viral infections due to inflammation and tissue injury associated with increased neutrophilic death. In this study, we used in vitro and in vivo approaches to investigate whether SerpinB1 regulates NETosis. We found that serpinb1-deficient bone marrow and lung neutrophils are hypersusceptible to NETosis induced by multiple mediators in both an NADPH-dependent and -independent manner, indicating a deeply rooted regulatory role in NETosis. This role is further supported by increased nuclear expansion (representing chromatin decondensation) of PMA-treated serpinb1-deficient neutrophils compared with wild-type, by migration of SerpinB1 from the cytoplasm to the nucleus of human neutrophils that is coincident with or preceding early conversion of lobulated (segmented) nuclei to delobulated (spherical) morphology, as well as by the finding that exogenous human recombinant SerpinB1 abrogates NET production. NETosis of serpinb1-deficient neutrophils is also increased in vivo during Pseudomonas aeruginosa lung infection. The findings identify a previously unrecognized regulatory mechanism involving SerpinB1 that restricts the production of NETs.
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Affiliation(s)
- Kalamo Farley
- Immune Disease Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
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Farley K, Stolley J, Zhao P, Cooley J, Remold-O'Donnell E. SerpinB1 is essential for regulation of neutrophil extracellular trap (NET) generation (118.3). The Journal of Immunology 2012. [DOI: 10.4049/jimmunol.188.supp.118.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
NETosis, a programmed death pathway induced in mature neutrophils by pathogens and inflammatory mediators, can be either a protective process that prevents spread of microbial infection or a pathological process that causes severe tissue damage and inflammation. Little is known about the mechanisms that regulate such a diverse functional spectrum. Previously we demonstrated serpinB1 null mice are highly susceptible to pulmonary Pseudomonas aeruginosa infection due to increased pathology mediated neutrophilic death. Using in vitro and in vivo approaches we examine the regulatory role of SerpinB1 in NETosis. We found bone marrow or LPS-derived serpinB1 null neutrophils are remarkably prone to NETosis in both NADPH-dependent and independent manner. A regulatory role for SerpinB1 in NETosis is also supported by the increased number of neutrophils with expanded nuclei, likely representing chromatin decondensation, and by finding that exogenous rSERPINB1 abrogates NET production. Importantly, during P. aeruginosa lung infection 4 times more NETs were harvested from serpinb1-/- mice than WT mice. The total number of in vitro activated serpinB1-/- neutrophils that died was not different from wild-type, indicating that the primary protective role of SerpinB1 is determining whether activated neutrophils die by the highly injurious NETs mechanism or by a less phlogistic mode, generating apoptotic-like cells with shrunken appearance and small nuclei.
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Affiliation(s)
- Kalamo Farley
- 1Immune Disease Institute, Harvard Medical School, Boston, MA
- 2Program in Cellular and Molecular Medicine, Children's Hosp. Boston, Boston, MA
- 3Pediatrics, Harvard Med. Sch., Boston, MA
| | - James Stolley
- 1Immune Disease Institute, Harvard Medical School, Boston, MA
- 2Program in Cellular and Molecular Medicine, Children's Hosp. Boston, Boston, MA
| | - Picheng Zhao
- 1Immune Disease Institute, Harvard Medical School, Boston, MA
- 2Program in Cellular and Molecular Medicine, Children's Hosp. Boston, Boston, MA
- 3Pediatrics, Harvard Med. Sch., Boston, MA
| | - Jessica Cooley
- 1Immune Disease Institute, Harvard Medical School, Boston, MA
- 2Program in Cellular and Molecular Medicine, Children's Hosp. Boston, Boston, MA
| | - Eileen Remold-O'Donnell
- 1Immune Disease Institute, Harvard Medical School, Boston, MA
- 2Program in Cellular and Molecular Medicine, Children's Hosp. Boston, Boston, MA
- 3Pediatrics, Harvard Med. Sch., Boston, MA
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Gong D, Farley K, White M, Hartshorn KL, Benarafa C, Remold-O'Donnell E. Critical role of serpinB1 in regulating inflammatory responses in pulmonary influenza infection. J Infect Dis 2011; 204:592-600. [PMID: 21791661 DOI: 10.1093/infdis/jir352] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Excessive inflammatory host response increases morbidity and mortality associated with seasonal respiratory influenza, and highly pathogenic virus strains are characterized by massive infiltration of monocytes and/or macrophages that produce a storm of injurious cytokines. METHODS Here, we examined the role in respiratory influenza of serpinB1, an endogenous inhibitor of the serine proteases elastase, cathepsin G, and proteinase-3, increasingly recognized as regulators of inflammation. RESULTS After challenge with high-dose surfactant protein-D (SP-D)-sensitive influenza A/Philadelphia/82 (H3N2), serpinB1(-/-) mice died earlier and in greater numbers than did wild-type mice. Sublethally infected animals suffered increased morbidity, delayed resolution of epithelial injury, and increased immune cell death. Viral clearance and SP-D/SP-A upregulation were unimpaired and so were early virus-induced cytokine and chemokine burst and influx of large numbers of neutrophils and monocytes. Whereas initial cytokines and chemokines rapidly cleared in wild-type mice, TNF-α, IL-6, KC/CXCL1, G-CSF, IL-17A, and MCP-1/CCL2 remained elevated in serpinB1(-/-) mice. Monocyte-derived cells were the dominant immune cells in influenza-infected lungs, and those from serpinB1(-/-) mice produced excessive IL-6 and TNF-α when tested ex vivo. Pulmonary γδ T-cells that produced IL-17A were also increased. CONCLUSIONS Because viral clearance was unimpaired, the study highlights the critical role of serpinB1 in mitigating inflammation and restricting pro-inflammatory cytokine production in influenza infection.
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Affiliation(s)
- Dapeng Gong
- Immune Disease Institute and Program in Cellular and Molecular Medicine at Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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Farley K, Stolley J, Cooley J, Remold-O'Donnell E. SerpinB1 functions in generating neutrophil extracellular traps (111.11). The Journal of Immunology 2011. [DOI: 10.4049/jimmunol.186.supp.111.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
SerpinB1 is a potent inhibitor of neutrophil serine proteases (NSPs), and mice deficient for serpinB1 showed reduced capacity to clear Pseudomonas aeruginosa lung infection, increase of proinflammatory cytokines and neutrophil death compared with wild type (WT) mice. Here we questioned whether this deficient anti-microbial protection might be caused by altered production of neutrophil extracellular traps (NETs). NETs, extruded chromatin associated with granule proteins including NSPs, capture and kill microbes, but excess NETs can cause tissue injury, e.g., impairment of lung function in patients with cystic fibrosis. On stimulation with phorbol myristate actetate (PMA) or platelet-activating factor (PAF), isolated bone marrow neutrophils of serpinB1-/- mice produced increased NETs compared with WT. Isolated lung neutrophils of LPS-treated serpinB1-/- mice also produced increased NETs compared with WT in response to PMA, and increased numbers of neutrophils with expanded nuclei. NET production was NADPH oxidase-dependent, and NADPH oxidase activity did not differ between the genotypes. Fluorescent microscopy showed that SerpinB1 translocated in PMA treated human neutrophils from the cytoplasm to the nucleus prior to nuclear membrane disintegration. SerpinB1 was also found as an extracellular component of NETs. These findings indicate that SerpinB1 contributes to regulation of NET formation and, by its presence in NETs, may protect against protease-induced tissue injury.
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Affiliation(s)
- Kalamo Farley
- 1Immune Disease Institute, Program in Cellular and Molecular Medicine at Children's Hospital, Harvard Medical School, Boston, MA
| | - James Stolley
- 1Immune Disease Institute, Program in Cellular and Molecular Medicine at Children's Hospital, Harvard Medical School, Boston, MA
| | - Jessica Cooley
- 1Immune Disease Institute, Program in Cellular and Molecular Medicine at Children's Hospital, Harvard Medical School, Boston, MA
| | - Eileen Remold-O'Donnell
- 1Immune Disease Institute, Program in Cellular and Molecular Medicine at Children's Hospital, Harvard Medical School, Boston, MA
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Benarafa C, LeCuyer TE, Baumann M, Stolley JM, Cremona TP, Remold-O'Donnell E. SerpinB1 protects the mature neutrophil reserve in the bone marrow. J Leukoc Biol 2011; 90:21-9. [PMID: 21248149 DOI: 10.1189/jlb.0810461] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SerpinB1 is among the most efficient inhibitors of neutrophil serine proteases--NE, CG, and PR-3--and we investigated here its role in neutrophil development and homeostasis. We found that serpinB1 is expressed in all human bone marrow leukocytes, including stem and progenitor cells. Expression levels were highest in the neutrophil lineage and peaked at the promyelocyte stage, coincident with the production and packaging of the target proteases. Neutrophil numbers were decreased substantially in the bone marrow of serpinB1(-/-) mice. This cellular deficit was associated with an increase in serum G-CSF levels. On induction of acute pulmonary injury, neutrophils were recruited to the lungs, causing the bone marrow reserve pool to be completely exhausted in serpinB1(-/-) mice. Numbers of myeloid progenitors were normal in serpinB1(-/-) bone marrow, coincident with the absence of target protease expression at these developmental stages. Maturation arrest of serpinB1(-/-) neutrophils was excluded by the normal CFU-G growth in vitro and the normal expression in mature neutrophils of early and late differentiation markers. Normal absolute numbers of proliferating neutrophils and pulse-chase kinetic studies in vivo showed that the bone marrow deficit in serpinB1(-/-) mice was largely restricted to mature, postmitotic neutrophils. Finally, upon overnight culture, apoptosis and necrosis were greater in purified bone marrow neutrophils from serpinB1(-/-) compared with WT mice. Collectively, these findings demonstrate that serpinB1 sustains a healthy neutrophil reserve that is required in acute immune responses.
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Affiliation(s)
- Charaf Benarafa
- Theodor Kocher Institute, Freiestrasse 1, 3006 Bern, Switzerland.
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Cooley J, Sontag MK, Accurso FJ, Remold-O'Donnell E. SerpinB1 in cystic fibrosis airway fluids: quantity, molecular form and mechanism of elastase inhibition. Eur Respir J 2010; 37:1083-90. [PMID: 20817705 DOI: 10.1183/09031936.00073710] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Neutrophil serine proteases (NSPs), especially elastase, are major agents of lung destruction in cystic fibrosis (CF) patients. This study investigated SerpinB1, a highly efficient inhibitor of NSPs, in CF lung disease. Bronchoalveolar lavage fluid (BALF) from 31 children with CF and 24 control children was examined for amount and molecular species of SerpinB1, and its mechanism of action was studied. CF BALF had more SerpinB1 than control BALF (geometric mean 3.9 (95% CI 2.60-5.62) versus 1.37 (1.20-1.55) μg·mL⁻¹; p<0.001). BALF levels of SerpinB1 were higher for infected versus uninfected CF subjects (5.5 versus 2.7 μg·mL⁻¹; p<0.04) and substantially higher for elastase-positive versus -negative CF subjects (8.41 versus 1.89 μg·mL⁻¹; p<0.001). Most SerpinB1 in CF BALF had been cleaved. Adding recombinant SerpinB1 to CF BALF stoichiometrically inhibited endogenous elastase, indicating that the inhibitor functions in the CF microenvironment. In vitro simulations comparing SerpinB1 and α₁-antitrypsin (SerpinA1) showed that both rapidly form irreversible inhibitory covalent complexes with elastase and that these differed in survival time. The SerpinB1-elastase complex survived only briefly due to fragmentation of bound elastase, releasing cleaved SerpinB1, the molecular form in CF BALF. The findings define an innate role for SerpinB1 in CF airways.
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Affiliation(s)
- J Cooley
- Immune Disease Institute, Boston, MA 02115, USA
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13
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Davies PL, Spiller OB, Beeton ML, Maxwell NC, Remold-O'Donnell E, Kotecha S. Relationship of proteinases and proteinase inhibitors with microbial presence in chronic lung disease of prematurity. Thorax 2010; 65:246-51. [PMID: 20335295 PMCID: PMC2921268 DOI: 10.1136/thx.2009.116061] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 12/01/2009] [Indexed: 11/18/2022]
Abstract
BACKGROUND A proteolytic imbalance has been implicated in the development of "classical" chronic lung disease of prematurity (CLD). However, in "new" CLD this pattern has changed. This study examines the longitudinal relationship between neutrophil proteinases and their inhibitors in ventilated preterm infants and their relationship to microbial colonisation. METHODS Serial bronchoalveolar lavage fluid was obtained from ventilated newborn preterm infants. Neutrophil elastase (NE) activity, cell counts, metalloproteinase (MMP)-9, MMP-9/TIMP-1 complex, SerpinB1 concentration and percentage of SerpinB1 and alpha(1)-antitrypsin (AAT) in complex with elastase were measured. The presence of microbial genes was examined using PCR for 16S rRNA genes. RESULTS Statistically more infants who developed CLD had NE activity in at least one sample (10/20) compared with infants with resolved respiratory distress syndrome (RDS) (2/17). However, NE activity was present in a minority of samples, occurring as episodic peaks. Peak levels of MMP-9, MMP-9/TIMP-1 complex, percentage of AAT and SerpinB1 in complex and cell counts were all statistically greater in infants developing CLD than in infants with resolved RDS. Peak values frequently occurred as episodic spikes and strong temporal relationships were noted between all markers. The peak values for all variables were significantly correlated to each other. The presence of bacterial 16S rRNA genes was associated with the development of CLD and with elevated elastase and MMP-9. CONCLUSION NE activity and MMP-9 appear to be important in the development of "new" CLD with both proteinase and inhibitor concentrations increasing episodically, possibly in response to postnatal infection.
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Affiliation(s)
- Philip L Davies
- Department of Child Health, Cardiff University, 5th Floor, University Hospital, Heath Park, Cardiff CF14 4XN, UK
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14
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Boilard E, Nigrovic PA, Larabee K, Watts GFM, Coblyn JS, Weinblatt ME, Massarotti EM, Remold-O'Donnell E, Farndale RW, Ware J, Lee DM. Platelets amplify inflammation in arthritis via collagen-dependent microparticle production. Science 2010; 327:580-3. [PMID: 20110505 DOI: 10.1126/science.1181928] [Citation(s) in RCA: 797] [Impact Index Per Article: 56.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In addition to their pivotal role in thrombosis and wound repair, platelets participate in inflammatory responses. We investigated the role of platelets in the autoimmune disease rheumatoid arthritis. We identified platelet microparticles--submicrometer vesicles elaborated by activated platelets--in joint fluid from patients with rheumatoid arthritis and other forms of inflammatory arthritis, but not in joint fluid from patients with osteoarthritis. Platelet microparticles were proinflammatory, eliciting cytokine responses from synovial fibroblasts via interleukin-1. Consistent with these findings, depletion of platelets attenuated murine inflammatory arthritis. Using both pharmacologic and genetic approaches, we identified the collagen receptor glycoprotein VI as a key trigger for platelet microparticle generation in arthritis pathophysiology. Thus, these findings demonstrate a previously unappreciated role for platelets and their activation-induced microparticles in inflammatory joint diseases.
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Affiliation(s)
- Eric Boilard
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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15
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Shcherbina A, Cooley J, Lutskiy MI, Benarafa C, Gilbert GE, Remold-O'Donnell E. WASP plays a novel role in regulating platelet responses dependent on alphaIIbbeta3 integrin outside-in signalling. Br J Haematol 2009; 148:416-27. [PMID: 19863535 DOI: 10.1111/j.1365-2141.2009.07959.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The most consistent feature of Wiskott Aldrich syndrome (WAS) is profound thrombocytopenia with small platelets. The responsible gene encodes WAS protein (WASP), which functions in leucocytes as an actin filament nucleating agent -yet- actin filament nucleation proceeds normally in patient platelets regarding shape change, filopodia and lamellipodia generation. Because WASP localizes in the platelet membrane skeleton and is mobilized by alphaIIbbeta3 integrin outside-in signalling, we questioned whether its function might be linked to integrin. Agonist-induced alphaIIbbeta3 activation (PAC-1 binding) was normal for patient platelets, indicating normal integrin inside-out signalling. Inside-out signalling (fibrinogen, JON/A binding) was also normal for wasp-deficient murine platelets. However, adherence/spreading on immobilized fibrinogen was decreased for patient platelets and wasp-deficient murine platelets, indicating decreased integrin outside-in responses. Another integrin outside-in dependent response, fibrin clot retraction, involving contraction of the post-aggregation actin cytoskeleton, was also decreased for patient platelets and wasp-deficient murine platelets. Rebleeding from tail cuts was more frequent for wasp-deficient mice, suggesting decreased stabilisation of the primary platelet plug. In contrast, phosphatidylserine exposure, a pro-coagulant response, was enhanced for WASP-deficient patient and murine platelets. The collective results reveal a novel function for WASP in regulating pro-aggregatory and pro-coagulant responses downstream of integrin outside-in signalling.
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Affiliation(s)
- Anna Shcherbina
- Immune Disease Institute, Harvard Medical School, Boston, MA, USA
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16
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Gong D, Benarafa C, Hartshorn KL, Remold-O'Donnell E. The neutrophil serine protease inhibitor SerpinB1 protects against inflammatory lung injury and morbidity in influenza virus infection (43.10). The Journal of Immunology 2009. [DOI: 10.4049/jimmunol.182.supp.43.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
SerpinB1 is an efficient inhibitor of neutrophil serine proteases. SerpinB1-/- mice fail to clear bacterial lung infection with increased inflammation and neutrophil death. Here, we investigated the role of serpinB1 in influenza virus infection, where infiltrating neutrophils and monocytes facilitate virus clearance but can also cause tissue injury. Influenza virus (H3N2 A/Phil/82) infection caused greater and more protracted body weight loss in serpinB1-/- vs. WT mice (20% vs. 15%; nadir on day 4 vs. day 3). Increased morbidity was not associated with defective virus clearance. Cytokines (IFNγ, TNFα, IL-17, IFNα, G-CSF) and chemokines (MIP-1α, KC, MIP-2) were increased in serpinB1-/- mice vs. WT on days 2-7 post-infection but not on day 1. In WT mice, histology indicated large infiltration of neutrophils peaking on day 1 and maximal airway injury on day 2 that resolved on day 3 coincident with the influx of monocytes/macrophages. In serpinB1-/- mice, neutrophils also peaked on day 1; epithelial injury was severe and sustained with accumulation of dead cells on day 2 and 3. Immunophenotyping of lung digests on day 2 and 3 showed delayed recruitment of monocytes, macrophages and DC in serpinB1-/- mice, but increase of activated CD4 (day 2-3) and CD8 (day 3) T cells. Our findings demonstrate that serpinB1 protects against morbidity and inflammatory lung injury associated with influenza infection. Funded by NIH AI072552.
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Affiliation(s)
- Dapeng Gong
- 1Immune Disease Institute, Boston, MA
- 2Department of Pediatrics, Harvard Medical School, Boston, MA
| | - Charaf Benarafa
- 1Immune Disease Institute, Boston, MA
- 2Department of Pediatrics, Harvard Medical School, Boston, MA
| | - Kevan L Hartshorn
- 3Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Eileen Remold-O'Donnell
- 1Immune Disease Institute, Boston, MA
- 2Department of Pediatrics, Harvard Medical School, Boston, MA
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17
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Lutskiy MI, Park JY, Remold SK, Remold-O'Donnell E. Evolution of highly polymorphic T cell populations in siblings with the Wiskott-Aldrich Syndrome. PLoS One 2008; 3:e3444. [PMID: 18941616 PMCID: PMC2567846 DOI: 10.1371/journal.pone.0003444] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Accepted: 09/10/2008] [Indexed: 12/12/2022] Open
Abstract
Population level evolutionary processes can occur within a single organism when the germ line contains a mutation that confers a cost at the level of the cell. Here we describe how multiple compensatory mutations arose through a within-individual evolutionary process in two brothers with the immune deficiency Wiskott-Aldrich Syndrome (WAS). As a result, both brothers have T lymphocyte populations that are highly polymorphic at the locus of the germ line defect, and no single allele achieves fixation. WASP, the gene product affected in this disease, is specific to white blood cells where it is responsible for regulating actin cytoskeleton dynamics in a wide range of cellular responses. The brothers inherited a rare allele predicted to result in truncated WASP lacking the carboxy-terminal VCA domains, the region that directly catalyzes actin filament generation. Although the brothers' T cell populations are highly polymorphic, all share a corrective effect relative to the inherited allele in that they restore the VCA domain. This indicates massive selection against the truncated germ line allele. No single somatic allele becomes fixed in the circulating T cell population of either brother, indicating that a regulated step in maturation of the affected cell lineage is severely compromised by the germ line allele. Based on the finding of multiple somatic mutations, the known maturation pathway for T-lineage cells and the known defects of T cells and precursor thymocytes in mice with truncated WASP, we hypothesize that the presence of truncated WASP (WASPΔVCA) confers an extreme disadvantage in early developing thymocytes, above and beyond the known cost of absence of full-length WASP, and that the disadvantage likely occurs through dominant negative competition of WASPΔVCA with N-WASP, a protein that otherwise partially compensates for WASP absence in developing thymocytes.
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Affiliation(s)
- Maxim I. Lutskiy
- Immune Disease Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jun Y. Park
- Immune Disease Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Susanna K. Remold
- Program on Disease Evolution, Department of Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Eileen Remold-O'Donnell
- Immune Disease Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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18
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Cooley J, McDonald B, Accurso FJ, Crouch EC, Remold-O'Donnell E. Patterns of neutrophil serine protease-dependent cleavage of surfactant protein D in inflammatory lung disease. J Leukoc Biol 2008; 83:946-55. [PMID: 18211966 DOI: 10.1189/jlb.1007684] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The manuscript presents definitive studies of surfactant protein D (SP-D) in the context of inflammatory lung fluids. The extent of SP-D depletion in bronchoalveolar lavage fluid (BALF) of children affected with cystic fibrosis (CF) is demonstrated to correlate best with the presence of the active neutrophil serine protease (NSP) elastase. Novel C-terminal SP-D fragments of 27 kDa and 11 kDa were identified in patient lavage fluid in addition to the previously described N-terminal, 35-kDa fragment by the use of isoelectrofocusing, modified blotting conditions, and region-specific antibodies. SP-D cleavage sites were identified. In vitro treatment of recombinant human SP-D dodecamers with NSPs replicated the fragmentation, but unexpectedly, the pattern of SP-D fragments generated by NSPs was dependent on calcium concentration. Whereas the 35- and 11-kDa fragments were generated when incubations were performed in low calcium (200 microM CaCl(2)), incubations in physiological calcium (2 mM) with higher amounts of elastase or proteinase-3 generated C-terminal 27, 21, and 14 kDa fragments, representing cleavage within the collagen and neck regions. Studies in which recombinant SP-D cleavage by individual NSPs was quantitatively evaluated under low and high calcium conditions showed that the most potent NSP for cleaving SP-D is elastase, followed by proteinase-3, followed by cathepsin G. These relative potency findings were considered in the context of other studies that showed that active NSPs in CF BALF are in the order: elastase, followed by cathepsin G, followed by proteinase-3. The findings support a pre-eminent role for neutrophil elastase as the critical protease responsible for SP-D depletion in inflammatory lung disease.
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Affiliation(s)
- Jessica Cooley
- Immune Disease Institute, Harvard Medical School, Boston, MA 02115, USA
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19
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Abstract
Patients with Wiskott-Aldrich syndrome (WAS), an X-linked blood cell disease, suffer from severe thrombocytopenia due to accelerated loss of defective platelets. The affected gene encodes WASP, an actin regulatory protein thought to reside in the cytoplasm of resting leucocytes. In contrast, this study showed that, for platelets, one-quarter of WASP molecules fractionate in the detergent-insoluble high speed pellet characterized as the membrane skeleton, the scaffold structure that underlies the lipid bilayer and stabilizes the surface membrane. Following treatment of platelets with thrombin and stirring, which induces cytoarchitectural remodelling, WASP and other membrane skeletal components sedimented at lower g force and partitioned in the low-speed pellet. Thrombin and stirring also induced WASP tyrosine phosphorylation, a rapid activating reaction, and proteolytic inactivation by cysteine protease calpain. Both the alteration of the sedimentation profile and the proteolytic inactivation were specific for the membrane skeletal pool of WASP and were abrogated in alphaIIb beta3 integrin-deficient platelets and in normal platelets treated with an integrin antagonist. The findings demonstrate that WASP is a component of the resting platelet membrane skeleton and participates in membrane skeletal rearrangements downstream of integrin outside-in signalling. The possible implications for the platelet defect in WAS are discussed.
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Affiliation(s)
- Maxim I Lutskiy
- The CBR Institute for Biomedical Research and the Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
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20
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Benarafa C, Priebe GP, Remold-O'Donnell E. The neutrophil serine protease inhibitor serpinb1 preserves lung defense functions in Pseudomonas aeruginosa infection. ACTA ACUST UNITED AC 2007; 204:1901-9. [PMID: 17664292 PMCID: PMC2118684 DOI: 10.1084/jem.20070494] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Neutrophil serine proteases (NSPs; elastase, cathepsin G, and proteinase-3) directly kill invading microbes. However, excess NSPs in the lungs play a central role in the pathology of inflammatory pulmonary disease. We show that serpinb1, an efficient inhibitor of the three NSPs, preserves cell and molecular components responsible for host defense against Pseudomonas aeruginosa. On infection, wild-type (WT) and serpinb1-deficient mice mount similar early responses, including robust production of cytokines and chemokines, recruitment of neutrophils, and initial containment of bacteria. However, serpinb1−/− mice have considerably increased mortality relative to WT mice in association with late-onset failed bacterial clearance. We found that serpinb1-deficient neutrophils recruited to the lungs have an intrinsic defect in survival accompanied by release of neutrophil protease activity, sustained inflammatory cytokine production, and proteolysis of the collectin surfactant protein–D (SP-D). Coadministration of recombinant SERPINB1 with the P. aeruginosa inoculum normalized bacterial clearance in serpinb1−/− mice. Thus, regulation of pulmonary innate immunity by serpinb1 is nonredundant and is required to protect two key components, the neutrophil and SP-D, from NSP damage during the host response to infection.
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Affiliation(s)
- Charaf Benarafa
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, MA 02115, USA.
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21
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Yasumatsu R, Altiok O, Benarafa C, Yasumatsu C, Bingol-Karakoc G, Remold-O'Donnell E, Cataltepe S. SERPINB1 upregulation is associated with in vivo complex formation with neutrophil elastase and cathepsin G in a baboon model of bronchopulmonary dysplasia. Am J Physiol Lung Cell Mol Physiol 2006; 291:L619-27. [PMID: 16617093 DOI: 10.1152/ajplung.00507.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bronchopulmonary dysplasia (BPD) continues to be a major cause of morbidity in premature infants. An imbalance between neutrophil elastase and its inhibitors has been implicated in BPD. Serine protease inhibitor (SERPIN)B1 is an inhibitor of neutrophil proteases, including neutrophil elastase (NE) and cathepsin G (cat G). Recent studies suggest that SERPINB1 could provide protection in the airways by regulating excess protease activity associated with inflammatory lung disorders. In this study, we determined the distribution and ontogeny of SERPINB1 in the baboon lung and characterized the expression of SERPINB1 in baboon models of BPD. SERPINB1 expression was detected in the conducting airway and glandular epithelial cells in addition to neutrophils, macrophages, and mast cells. SERPINB1 mRNA and protein expression increased with advancing gestational age and in the new BPD model. In contrast, SERPINB1 expression levels were decreased in the old BPD model. Furthermore, SERPINB1 was detected as a high-molecular-mass (HMM) complex in lung tissue and bronchoalveolar lavage fluid samples from the BPD group. Analysis of the HMM complex by coimmunoprecipitation showed that these complexes were formed between SERPINB1 and NE or cat G. High-performance liquid chromatography (HPLC) ion trap mass spectrometry verified the presence of SERPINB1 in HMM complexes. Finally, NE activity level was compared between new and old baboon models of BPD and was found to be significantly lower in new BPD. Thus SERPINB1 upregulation in new BPD may be protective by contributing to the regulation of neutrophil proteases NE and cat G.
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Affiliation(s)
- Ryuji Yasumatsu
- Division of Newborn Medicine, Children's Hospital, and Harvard Medical School, Boston, MA 02115, USA
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22
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Benarafa C, Remold-O'Donnell E. The ovalbumin serpins revisited: perspective from the chicken genome of clade B serpin evolution in vertebrates. Proc Natl Acad Sci U S A 2005; 102:11367-72. [PMID: 16055559 PMCID: PMC1183561 DOI: 10.1073/pnas.0502934102] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Serpin superfamily proteins, most of which are serine protease inhibitors, share an unusual mechanism rooted in their conserved metastable tertiary structure. Although serpins have been identified in isolated members of archea, bacteria, and plants, a remarkable expansion is found in vertebrates. The chicken protein ovalbumin, a storage protein from egg white, lacking protease inhibitory activity, is an historical member of the superfamily and the founding member of the subgroup known as ov-serpins (ovalbumin-related serpins) or clade B serpins. In the human, ov-serpins include 13 proteins involved in the regulation of inflammation, apoptosis, angiogenesis, and embryogenesis. Here, a detailed analysis of the chicken (Gallus gallus) genome identified 10 clade B serpin genes that map to a single approximately 150-kb locus and contain the signature protein sequence of serpins and the gene structure of ov-serpins, with either seven or eight exons. Orthologues of PAI-2 (SERPINB2), MNEI (SERPINB1), PI-6 (SERPINB6), and maspin (SERPINB5) are highly conserved. Comparison with human ov-serpins identified avian-specific and mammal-specific genes. Importantly, a unique model of mammalian ov-serpin evolution is revealed from the comparative analysis of the chicken and human loci. The presence of a subset of ov-serpin genes in zebrafish (Danio rerio) gives insight into the ancestral locus. This comparative genomic study provides a valuable perspective on the evolutionary pathway for the clade B serpins, allowing the identification of genes with functions that may have been conserved since the origin of vertebrates. In addition, it suggests that "newer" serpins, such as ovalbumin, have contributed to vertebrate adaptation.
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Affiliation(s)
- Charaf Benarafa
- CBR Institute for Biomedical Research and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
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23
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Abstract
Wiskott-Aldrich syndrome (WAS) is a platelet/immunodeficiency disease arising from mutations of WAS protein (WASP), a hemopoietic cytoskeletal protein. Clinical symptoms vary widely from mild (X-linked thrombocytopenia) to life threatening. In this study, we examined the molecular effects of individual mutations by quantifying WASP in peripheral lymphocytes of 44 patients and identifying the molecular variant (collectively called proteotype). Nonpredicted proteotypes were found for 14 genotypes. These include WASP-negative lymphocytes found for five missense genotypes and WASP-positive lymphocytes for two nonsense, five frameshift, and two splice site genotypes. Missense mutations in the Ena/VASP homology 1 (EVH1) domain lead to decreased/absent WASP but normal mRNA levels, indicating that proteolysis causes the protein deficit. Because several of the EVH1 missense mutations alter WIP binding sites, the findings suggest that abrogation of WIP binding induces proteolysis. Whereas platelets of most patients were previously shown to lack WASP, WASP-positive platelets were found for two atypical patients, both of whom have mutations outside the EVH1 domain. WASP variants with alternative splicing and intact C-terminal domains were characterized for eight nonsense and frameshift genotypes. One of these, a nonsense genotype in a mild patient, supports expression of WASP lacking half of the proline-rich region. With one notable exception, genotype and proteotype were linked, indicating that a genotype-proteotype registry could be assembled to aid in predicting disease course and planning therapy for newly diagnosed infants. Knowledge of the molecular effect of mutations would aid also in identifying disease-modifying genes.
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Affiliation(s)
- Maxim I Lutskiy
- CBR Institute for Biomedical Research, and Department of Pediatrics, Harvard Medical School, 800 Huntington Avenue, Boston, MA 02115, USA
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24
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Abstract
Rare cases of somatic mosaicism resulting from reversion of inherited mutations can lead to the attenuation of blood-cell disorders, including Wiskott-Aldrich syndrome (WAS). The impact of the revertant hematopoietic stem or progenitor cells, particularly their representation in blood-cell populations, is of interest because it predicts the outcome of gene therapy. Here we report an 8-year-old patient with WAS caused by a single nucleotide insertion in the WASP gene that abrogates protein expression. The patient nonetheless had mild disease. We found reversion of the mutation in a fraction of patient lymphocytes. Forty percent of natural killer (NK) cells expressed Wiskott-Aldrich syndrome protein (WASP), and NK cells contained both mutated and revertant (normal) sequences. WASP was not expressed in patient T or B cells; T cells contained only the mutated sequence. The selective advantage of WASP+ NK cells was also demonstrated for carrier females. The enrichment of WASP+-revertant NK cells indicates that WASP provides a selective advantage in this lineage and predicts the success of gene therapy for reconstituting the NK-cell compartment. The importance of reconstituting the NK-cell lineage is discussed.
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Affiliation(s)
- Maxim I Lutskiy
- The CBR Institute for Biomedical Research, Inc., Boston, MA 02115, USA
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25
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Abstract
Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency/platelet disease due to mutations of WASP, a cytoskeletal regulatory protein of blood cells. Patients exhibit a range of immune defects generally attributed to defective T-cell function, including poor response to immunization, skewed immunoglobulin isotypes, eczema, recurrent infections, autoimmune disease and increased frequency of malignancies. Here we show a deficit of total B-cells in WAS patients of various ages and identify phenotypic perturbations involving complement receptors and CD27. Whereas B-cells of normal healthy donors are overwhelmingly CD21/CD35-positive, B-cells expressing these receptors are significantly reduced in number in WAS patients, and their paucity may cause suboptimal antigen capture and presentation. The frequencies of IgD(-) and IgG(+) patient B-cells were not different from healthy donors (although absolute numbers were decreased), indicating that isotype switching is occurring. In contrast, the frequency of cells positive for CD27, the marker of post germinal centre B-cells, was significantly decreased even among isotype-switched cells, and B-cells resembling germinal centre progenitors (CD10(+)CD27(-)CD38(bright)) were more frequent in adult patients, suggesting impaired germinal centre maturation/differentiation. The documentation of these phenotypic perturbations and deficit of total cells suggest that defects intrinsic to B-cells contribute to the impaired humoral immunity that characterizes this disease.
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Affiliation(s)
- J Y Park
- The CBR Institute for Biomedical Research, Harvard Medical School, Boston, MA 02115, USA
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26
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Woods DE, Cantin A, Cooley J, Kenney DM, Remold-O'Donnell E. Aerosol treatment with MNEI suppresses bacterial proliferation in a model of chronic Pseudomonas aeruginosa lung infection. Pediatr Pulmonol 2005; 39:141-9. [PMID: 15633200 DOI: 10.1002/ppul.20167] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neutrophil elastase is present at high levels in airway fluid of patients with cystic fibrosis (CF), and is responsible for considerable inflammatory damage. Human monocyte/neutrophil elastase inhibitor (MNEI), a 42-kDa serpin protein, is an effective inhibitor of neutrophil elastase, cathepsin G, and proteinase-3, related proteases released from inflammatory neutrophils. We hypothesized that recombinant MNEI would reduce inflammatory damage and enhance bacterial clearance from the lung in an animal model of chronic Pseudomonas aeruginosa infection. In vitro studies showed that MNEI causes dose-dependent inhibition of the activity of rat neutrophil elastase. Recombinant MNEI was administered daily by aerosolization to rats previously inoculated with agar beads containing P. aeruginosa to initiate chronic infection. Administered MNEI was partially recovered in lavage fluid of treated rats as a 66-kDa complex with protease indicative of in vivo inhibition of elastase or a related protease. Aerosol treatment with MNEI significantly decreased the extent of inflammatory injury, quantified as the histopathology score. MNEI, which had no bactericidal effect on P. aeruginosa in vitro, significantly enhanced clearance of bacteria from infected rat lungs. The reduction of histopathology scores and enhancement of bacterial killing were evident 6 hr after a single aerosol treatment with MNEI. These findings indicate an important function of MNEI in protecting innate antimicrobial defense. Similar results were previously obtained for aerosolized prolastin (alpha1-antitrypsin), indicating that enhanced bacterial clearance by MNEI is due to inhibition of neutrophil protease. These findings demonstrate the value of this nonantibiotic protease inhibitor as an adjunct for the treatment and prevention of the infection component of CF lung disease.
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Affiliation(s)
- Donald E Woods
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
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Thongboonkerd V, Barati MT, McLeish KR, Benarafa C, Remold-O'Donnell E, Zheng S, Rovin BH, Pierce WM, Epstein PN, Klein JB. Alterations in the renal elastin-elastase system in type 1 diabetic nephropathy identified by proteomic analysis. J Am Soc Nephrol 2004; 15:650-62. [PMID: 14978167 DOI: 10.1097/01.asn.0000115334.65095.9b] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Diabetes now accounts for >40% of patients with ESRD. Despite significant progress in understanding diabetic nephropathy, the cellular mechanisms that lead to diabetes-induced renal damage are incompletely defined. For defining changes in protein expression that accompany diabetic nephropathy, the renal proteome of 120-d-old OVE26 transgenic mice with hypoinsulinemia, hyperglycemia, hyperlipidemia, and proteinuria were compared with those of background FVB nondiabetic mice (n = 5). Proteins derived from whole-kidney lysate were separated by two-dimensional PAGE and identified by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. Forty-one proteins from 300 visualized protein spots were differentially expressed in diabetic kidneys. Among these altered proteins, expression of monocyte/neutrophil elastase inhibitor was increased, whereas elastase IIIB was decreased, leading to the hypothesis that elastin expression would be increased in diabetic kidneys. Renal immunohistochemistry for elastin of 325-d-old FVB and OVE26 mice demonstrated marked accumulation of elastin in the macula densa, collecting ducts, and pelvicalyceal epithelia of diabetic kidneys. Elastin immunohistochemistry of human renal biopsies from patients with type 1 diabetes (n = 3) showed increased elastin expression in renal tubular cells and the interstitium but not glomeruli. These results suggest that coordinated changes in elastase inhibitor and elastase expression result in increased tubulointerstitial deposition of elastin in diabetic nephropathy. The identification of these coordinated changes in protein expression in diabetic nephropathy indicates the potential value of proteomic analysis in defining pathophysiology.
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Affiliation(s)
- Visith Thongboonkerd
- Kidney Disease Program, Department of Medicine, University of Louisville, Louisville, Kentucky, USA.
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Hirche TO, Crouch EC, Espinola M, Brokelman TJ, Mecham RP, DeSilva N, Cooley J, Remold-O'Donnell E, Belaaouaj A. Neutrophil Serine Proteinases Inactivate Surfactant Protein D by Cleaving within a Conserved Subregion of the Carbohydrate Recognition Domain. J Biol Chem 2004; 279:27688-98. [PMID: 15078883 DOI: 10.1074/jbc.m402936200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Surfactant protein D (SP-D) plays important roles in innate immunity including the defense against bacteria, fungi, and respiratory viruses. Because SP-D specifically interacts with neutrophils that infiltrate the lung in response to acute inflammation and infection, we examined the hypothesis that the neutrophil-derived serine proteinases (NSPs): neutrophil elastase, proteinase-3, and cathepsin G degrade SP-D. All three human NSPs specifically cleaved recombinant rat and natural human SP-D dodecamers in a time- and dose-dependent manner, which was reciprocally dependent on calcium concentration. The NSPs generated similar, relatively stable, disulfide cross-linked immunoreactive fragments of approximately 35 kDa (reduced), and sequencing of a major catheptic fragment definitively localized the major sites of cleavage to a highly conserved subregion of the carbohydrate recognition domain. Cleavage markedly reduced the ability of SP-D to promote bacterial aggregation and to bind to yeast mannan in vitro. Incubation of SP-D with isolated murine neutrophils led to the generation of similar fragments, and cleavage was inhibited with synthetic and natural serine proteinase inhibitors. In addition, neutrophils genetically deficient in neutrophil elastase and/or cathepsin G were impaired in their ability to degrade SP-D. Using a mouse model of acute bacterial pneumonia, we observed the accumulation of SP-D at sites of neutrophil infiltration coinciding with the appearance of approximately 35-kDa SP-D fragments in bronchoalveolar lavage fluids. Together, our data suggest that neutrophil-derived serine proteinases cleave SP-D at sites of inflammation with potential deleterious effects on its biological functions.
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Affiliation(s)
- Tim O Hirche
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110, USA
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Rubio F, Cooley J, Accurso FJ, Remold-O'Donnell E. Linkage of neutrophil serine proteases and decreased surfactant protein-A (SP-A) levels in inflammatory lung disease. Thorax 2004; 59:318-23. [PMID: 15047952 PMCID: PMC1763800 DOI: 10.1136/thx.2003.014902] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND In patients with cystic fibrosis (CF) neutrophils are recruited in excess to the airways yet pathogens are not cleared and the patients suffer from chronic infections. Recent studies have shown a deficiency in airway fluids from patients with CF and other inflammatory pulmonary conditions of surfactant protein A (SP-A), a pattern recognition molecule that facilitates uptake of microbes by macrophages and neutrophils. METHODS In vitro simulations were used to test the hypothesis that decreased SP-A levels in CF might be the result of degradation by neutrophil serine proteases. RESULTS Very low levels of the neutrophil granule serine proteases cathepsin G, elastase, and proteinase-3 rapidly degraded pure SP-A when tested in buffered saline. The order of potency was cathepsin G>elastase>proteinase-3. The addition of cathepsin G or elastase to normal bronchoalveolar lavage (BAL) fluid caused a dose dependent degradation of endogenous native SP-A. Cathepsin G and elastase were present in the BAL fluid from many patients with CF. Simple incubation of protease positive BAL fluid from patients with CF caused a time dependent degradation of added SP-A or, where present, endogenous SP-A. The degradation of SP-A by protease(s) in BAL fluid of patients with CF was abrogated by diisopropylfluorophosphate and monocyte/neutrophil elastase inhibitor. CONCLUSIONS The findings strongly suggest that the neutrophil serine proteases cathepsin G and/or elastase and/or proteinase-3 contribute to degradation of SP-A and thereby diminish innate pulmonary antimicrobial defence.
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Affiliation(s)
- F Rubio
- CBR Institute for Biomedical Research Inc, Harvard Medical School, Boston, Massachusetts, USA
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31
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Park JY, Kob M, Prodeus AP, Rosen FS, Shcherbina A, Remold-O'Donnell E. Early deficit of lymphocytes in Wiskott-Aldrich syndrome: possible role of WASP in human lymphocyte maturation. Clin Exp Immunol 2004; 136:104-10. [PMID: 15030520 PMCID: PMC1809006 DOI: 10.1111/j.1365-2249.2004.02409.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2004] [Indexed: 11/28/2022] Open
Abstract
Wiskott-Aldrich syndrome (WAS) is an X-linked platelet/immunodeficiency disease. The affected gene encodes WASP, a multidomain protein that regulates cytoskeletal assembly in blood cells. Patients have recurring infections, and their lymphocytes exhibit deficient proliferative responses in vitro. We report an evaluation of peripheral blood lymphocytes of 27 WAS patients, aged one month to 55 years. Whereas NK cells were normal, a significant deficit of T and B lymphocytes was observed. The number of lymphocytes was already decreased in infant patients, suggesting deficient output. Both CD4 and CD8 T lymphocytes were affected; the decrease was most pronounced for naïve T cells. Naïve CD4 lymphocytes of patients showed normal expression of Bcl-2, and Ki-67, and normal survival in vitro, suggesting that their in vivo survival and proliferation are normal. The collective data suggest that the patients' lymphocyte deficit results from deficient output, likely due to abnormal lymphocyte maturation in the thymus and bone marrow. We propose that WASP plays an important role not only in the function of mature T lymphocytes, but also in the maturation of human T and B lymphocytes and that impaired lymphocyte maturation is central to the aetiology of WAS immunodeficiency.
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Affiliation(s)
- J Y Park
- The CBR Institute for Biomedical Research, Harvard Medical School, Boston 02115, USA
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Benarafa C, Cooley J, Zeng W, Bird PI, Remold-O'Donnell E. Characterization of four murine homologs of the human ov-serpin monocyte neutrophil elastase inhibitor MNEI (SERPINB1). J Biol Chem 2002; 277:42028-33. [PMID: 12189154 DOI: 10.1074/jbc.m207080200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human ov-serpin monocyte neutrophil elastase inhibitor (MNEI) is encoded by a single gene SERPINB1. It is a highly efficient inhibitor of neutrophil granule proteases. Four murine genes with high sequence identity with MNEI were identified and fully sequenced, and these were named EIA, EIB, EIC, and EID. EIA, EIB and EIC showed the same seven-exon gene structure as SERPINB1. However, EIC included an additional, alternatively spliced, exon due to the insertion of an endogenous retrovirus-like sequence. EID lacked several exons and is a pseudogene. Reverse transcriptase-PCR showed that EIA, like MNEI, is expressed at high levels in many tissues. EIB is mainly expressed in brain, and EIC was only expressed as splicing variants unlikely to encode a functional serpin. Upon incubation with serine proteases, EIA formed inhibitory covalent complexes with pancreatic and neutrophil elastases, cathepsin G, proteinase-3, and chymotrypsin, as previously shown for MNEI, whereas EIB was only able to do so with cathepsin G. According to the new serpin nomenclature, the genes encoding EIA, EIB, EIC, and EID will be called Serpinb1, Serpinb1b, Serpinb1c, and Serpinb1-ps1. These data demonstrate that the four murine homologs of MNEI have met different evolutionary fates, and that EIA is the mouse ortholog of MNEI.
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Affiliation(s)
- Charaf Benarafa
- Center for Blood Research, Boston, Massachusetts 02115, USA.
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34
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Abstract
Wiskott-Aldrich syndrome (WAS) is an X-linked disease characterized by thrombocytopenia, eczema, and various degrees of immune deficiency. Carriers of mutated WASP have nonrandom X chromosome inactivation in their blood cells and are disease-free. We report data on a 14-month-old girl with a history of WAS in her family who presented with thrombocytopenia, small platelets, and immunologic dysfunction. Sequencing of the WASP gene showed that the patient was heterozygous for the splice site mutation previously found in one of her relatives with WAS. Sequencing of all WASP exons revealed no other mutation. Levels of WASP in blood mononuclear cells were 60% of normal. Flow cytometry after intracellular staining of peripheral blood mononuclear cells with WASP monoclonal antibody revealed both WASP(bright) and WASP(dim) populations. X chromosome inactivation in the patient's blood cells was found to be random, demonstrating that both maternal and paternal active X chromosomes are present. These findings indicate that the female patient has a defect in the mechanisms that lead in disease-free WAS carriers to preferential survival/proliferation of cells bearing the active wild-type X chromosome. Whereas the patient's lymphocytes are skewed toward WASP(bright) cells, about 65% of her monocytes and the majority of her B cells (CD19(+)) are WASP(dim). Her naive T cells (CD3(+)CD45RA(+)) include WASP(bright) and WASP(dim) populations, but her memory T cells (CD3(+)CD45RA(-)) are all WASP(bright). After activation in vitro of T cells, all cells exhibited CD3(+)CD45RA(-) phenotype and most were WASP(bright) with active paternal (wild-type) X chromosome, suggesting selection against the mutated WASP allele during terminal T-cell maturation/differentiation.
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Affiliation(s)
- Maxim I Lutskiy
- Center for Blood Research, and the Division of Immunology, Children's Hospital, and the Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
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35
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Orange JS, Ramesh N, Remold-O'Donnell E, Sasahara Y, Koopman L, Byrne M, Bonilla FA, Rosen FS, Geha RS, Strominger JL. Wiskott-Aldrich syndrome protein is required for NK cell cytotoxicity and colocalizes with actin to NK cell-activating immunologic synapses. Proc Natl Acad Sci U S A 2002; 99:11351-6. [PMID: 12177428 PMCID: PMC123260 DOI: 10.1073/pnas.162376099] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Wiskott-Aldrich syndrome (WAS) is a primary immunodeficiency disorder caused by a mutation in WAS protein (WASp) that results in defective actin polymerization. Although the function of many hematopoietic cells requires WASp, the specific expression and function of this molecule in natural killer (NK) cells is unknown. Here, we report that WAS patients have increased percentages of peripheral blood NK cells and that fresh enriched NK cells from two patients with a WASp mutation have defective cytolytic function. In normal NK cells, WASp was expressed and localized to the activating immunologic synapse (IS) with filamentous actin (F-actin). Perforin also localized to the NK cell-activating IS but at a lesser frequency than F-actin and WASp. The accumulation of F-actin and WASp at the activating IS was decreased significantly in NK cells that had been treated with the inhibitor of actin polymerization, cytochalasin D. NK cells from WAS patients lacked expression of WASp and accumulated F-actin at the activating IS infrequently. Thus, WASp has an important function in NK cells. In patients with WASp mutations, the resulting NK cell defects are likely to contribute to their disease.
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Affiliation(s)
- Jordan S Orange
- Department of Molecular and Cellular Biology, 7 Divinity Avenue, Harvard University, Cambridge, MA 02138, USA.
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Jones LN, Lutskiy MI, Cooley J, Kenney DM, Rosen FS, Remold-O'Donnell E. A novel protocol to identify mutations in patients with wiskott-Aldrich syndrome. Blood Cells Mol Dis 2002; 28:392-8. [PMID: 12367583 DOI: 10.1006/bcmd.2002.0523] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mutations of WASP (Wiskott-Aldrich syndrome protein) underlie the severe immunodeficiency/platelet disorder Wiskott-Aldrich syndrome (WAS) and its milder variant X-linked thrombocytopenia (XLT). The affected gene, a 12-exon structure on the X-chromosome, is expressed exclusively in blood cells. The encoded product WASP is a 502-amino-acid scaffolding protein that functions in stimulus-induced nucleation of actin filaments to form dynamic cell surface projections. To date, more than 150 mutations have been identified in 300 WAS/XLT kindred worldwide, generally through methodologies that include sophisticated exon screening steps such as single-strand conformation analysis. We report here a simpler protocol, which was designed for use in clinical settings to identify the mutations of newly diagnosed patients. The approach relies on directly sequencing amplified exons according to a staggered schedule based on statistical evaluation of previous cases. In a 2 1/2-year trial, samples from 28 consecutive patients were analyzed; these included 3 "blindly labeled" previously studied cases. The mutations that were identified include a broad spectrum (8 missense, 3 nonsense, 5 splice site mutations, 11 small insertion/deletions, 1 large deletion) and were broadly distributed (in 10 of the 12 exons). All mutations were verified and no discrepancies were encountered. Per patient, a mean of six DNA sequencing reactions and 6-7 h of staff effort sufficed for mutation identification and verification, indicating that the protocol is cost-effective. This cumulative experience demonstrates the suitability, reliability, and versatility of the new protocol.
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Affiliation(s)
- L N Jones
- Center for Blood Research, Boston, Massachusetts 02115, USA
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37
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Lutskiy MI, Jones LN, Rosen FS, Remold-O'Donnell E. An Alu-mediated deletion at Xp11.23 leading to Wiskott-Aldrich syndrome. Hum Genet 2002; 110:515-9. [PMID: 12073025 DOI: 10.1007/s00439-002-0716-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2002] [Accepted: 02/25/2002] [Indexed: 10/27/2022]
Abstract
Wiskott-Aldrich syndrome (WAS) is an X-linked disease characterized by thrombocytopenia, eczema and immunodeficiency of varying severity. The WASP gene, mutations of which are responsible for the phenotype, maps to Xp11.23. We describe here a patient with a large deletion in the Xp11.23 region. The deletion, which totals 15.8 kb, begins downstream of DXS1696 and encompasses 13 kb upstream of WASP and includes the distal and proximal promoters and exons 1-6. Analysis of the 5'-boundary region identified sequences missing in the Human Genome database and, as a result, the normal DNA sequence was revised to include 743 bp of novel sequence (AF466616). The patient's upstream breakpoint was localized to an AluSg element within a highly repetitive DNA region containing other Alu elements. A 26-bp recombinogenic element is located downstream of the 5' breakpoint. A 16-bp sequence just upstream of the 5' breakpoint shares close homology with the sequence that spans the 3' breakpoint in intron 6. A heptanucleotide of unknown origin, CAGGGGG, links the 5' and 3' breakpoints. To our knowledge this is the largest deletion in a WAS patient.
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Affiliation(s)
- Maxim I Lutskiy
- The Center for Blood Research, Harvard Medical School, Huntington Avenue, Boston, MA 02115, USA
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38
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Kaiserman D, Knaggs S, Scarff KL, Gillard A, Mirza G, Cadman M, McKeone R, Denny P, Cooley J, Benarafa C, Remold-O'Donnell E, Ragoussis J, Bird PI. Comparison of human chromosome 6p25 with mouse chromosome 13 reveals a greatly expanded ov-serpin gene repertoire in the mouse. Genomics 2002; 79:349-62. [PMID: 11863365 DOI: 10.1006/geno.2002.6716] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ov-serpins are intracellular proteinase inhibitors implicated in the regulation of tumor progression, inflammation, and cell death. The 13 human ov-serpin genes are clustered at 6p25 (3 genes) and 18q21 (10 genes), and share common structures. We show here that a 1-Mb region on mouse chromosome 13 contains at least 15 ov-serpin genes compared with the three ov-serpin genes within 0.35 Mb at human 6p25 (SERPINB1 (MNEI), SERPINB6 (PI-6), SER-PINB9 (PI-9)). The mouse serpins have characteristics of functional inhibitors and fall into three groups on the basis of similarity to MNEI, PI-6, or PI-9. The genes map between the mouse orthologs of the Werner helicase interacting protein and NAD(P)H menadioine oxidoreductase 2 genes, in a region that contains the markers D13Mit136 and D13Mit116. They have the seven-exon structure typical of human 6p25 ov-serpin genes, with identical intron phasing. Most show restricted patterns of expression, with common sites of synthesis being the placenta and immune tissue. Compared with human, this larger mouse serpin repertoire probably reflects the need to regulate a larger proteinase repertoire arising from differing evolutionary pressures on the reproductive and immune systems.
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Affiliation(s)
- Dion Kaiserman
- Department of Biochemistry and Molecular Biology, Monash University, 3800, Australia
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Cooley J, Takayama TK, Shapiro SD, Schechter NM, Remold-O'Donnell E. The serpin MNEI inhibits elastase-like and chymotrypsin-like serine proteases through efficient reactions at two active sites. Biochemistry 2001; 40:15762-70. [PMID: 11747453 DOI: 10.1021/bi0113925] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
MNEI (monocyte/neutrophil elastase inhibitor) is a 42 kDa serpin superfamily protein characterized initially as a fast-acting inhibitor of neutrophil elastase. Here we show that MNEI has a broader specificity, efficiently inhibiting proteases with elastase- and chymotrypsin-like specificities. Reaction of MNEI with neutrophil proteinase-3, an elastase-like protease, and porcine pancreatic elastase demonstrated rapid inhibition rate constants >10(7) M(-1) s(-1), similar to that observed for neutrophil elastase. Reactions of MNEI with chymotrypsin-like proteases were also rapid: cathepsin G from neutrophils (>10(6) M(-1) s(-1)), mast cell chymase (>10(5) M(-1) s(-1)), chymotrypsin (>10(6) M(-1) s(-1)), and prostate-specific antigen (PSA), which had the slowest rate constant at approximately 10(4) M(-1) s(-1). Inhibition of trypsin-like (plasmin, granzyme A, and thrombin) and caspase-like (granzyme B) serine proteases was not observed or highly inefficient (trypsin), nor was inhibition of proteases from the cysteine (caspase-1 and caspase-3) and metalloprotease (macrophage elastase, MMP-12) families. The stoichiometry of inhibition for all inhibitory reactions was near 1, and inhibitory complexes were resistant to dissociation by SDS, further indicating the specificity of MNEI for elastase- and chymotrypsin-like proteases. Determination of the reactive site of MNEI by N-terminal sequencing and mass analysis of reaction products identified two reactive sites, each with a different specificity. Cys(344), which corresponds to Met(358), the P(1) site of alpha1-antitrypsin, was the inhibitory site for elastase-like proteases and PSA, while the preceding residue, Phe(343), was the inhibitory site for chymotrypsin-like proteases. This study demonstrates that MNEI has two functional reactive sites corresponding to the predicted P(1) and P(2) positions of the reactive center loop. The data suggest that MNEI plays a regulatory role at extravascular sites to limit inflammatory damage due to proteases of cellular origin.
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Affiliation(s)
- J Cooley
- Center for Blood Research, Harvard Medical School, 800 Huntington Avenue, Boston, Massachusetts 02115, USA
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Abstract
Mutations of Wiskott-Aldrich syndrome protein (WASP) underlie the severe thrombocytopenia and immunodeficiency of the Wiskott-Aldrich syndrome. WASP, a specific blood cell protein, and its close homologue, the broadly distributed N-WASP, function in dynamic actin polymerization processes. Here it is demonstrated that N-WASP is expressed along with WASP, albeit at low levels, in human blood cells. The presence of approximately 160 nmol/L rapidly acting N-WASP molecules may explain the normal capacity of WASP-negative patient platelets for early agonist-induced aggregation and filopodia formation. Ex vivo experiments revealed a significant difference between WASP and N-WASP in sensitivity to calpain, the Ca++-dependent protease activated in agonist-stimulated platelets. Through the use of a series of calpain-containing broken cell systems, it is shown that WASP is cleaved in a Ca++-dependent reaction inhibitable by calpeptin and E64d and that N-WASP is not cleaved, suggesting that the cleavage of WASP by calpain functions in normal platelets as part of a Ca++-dependent switch mechanism that terminates the surface projection phase of blood cell activation processes.
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Affiliation(s)
- A Shcherbina
- Center for Blood Research and the Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
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Loutski M, Remold-O'Donnell E, Roumiantsev AG, Shcherbina A. Regulation of Anti-Tumor Activity Using Monoclonal Antibodies to Alpha-Fetoprotein Receptor and after Immunization with This Protein. Russ J Immunol 2001; 6:257-264. [PMID: 12687225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Wiskott-Aldrich syndrome (WAS), an inherited blood cell disorder due to mutations of the X-chromosome gene WASP (Wiskott-Aldrich Syndrome Protein), was characterized originally by thrombocytopenia, immunodeficiency and eczema. Whereas platelet dysfunction is severe and consistent, immune defects are clinically variable, ranging from negligible to life-threatening. To understand this heterogeneity, WASP was quantified in peripheral blood mononuclear cells of patients with diverse mutations. In this study we assessed the relationship between the mutation, protein expression and phenotype in WAS patients. The majority of the patients with missense mutations exhibited mild phenotype, whereas patients with premature stop codon were in most cases severe. We designed a one-step approach intended for use in identifying mutations in samples from newly diagnosed patients. The approach relies on direct sequencing of amplified exon regions in a staggered schedule that was based on the mutation distribution frequency in previous cases. The method proved to be fast and reliable. Definitive mutation information was generated for each patient studied.
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Affiliation(s)
- Maxim Loutski
- Research Institute for Pediatric Hematology, Moscow, Russia
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Silverman GA, Bird PI, Carrell RW, Church FC, Coughlin PB, Gettins PG, Irving JA, Lomas DA, Luke CJ, Moyer RW, Pemberton PA, Remold-O'Donnell E, Salvesen GS, Travis J, Whisstock JC. The serpins are an expanding superfamily of structurally similar but functionally diverse proteins. Evolution, mechanism of inhibition, novel functions, and a revised nomenclature. J Biol Chem 2001; 276:33293-6. [PMID: 11435447 DOI: 10.1074/jbc.r100016200] [Citation(s) in RCA: 894] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- G A Silverman
- Department of Pediatrics, Division of Newborn Medicine, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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43
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Fratazzi C, Manjunath N, Arbeit RD, Carini C, Gerken TA, Ardman B, Remold-O'Donnell E, Remold HG. A macrophage invasion mechanism for mycobacteria implicating the extracellular domain of CD43. J Exp Med 2000; 192:183-92. [PMID: 10899905 PMCID: PMC2193255 DOI: 10.1084/jem.192.2.183] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We studied the role of CD43 (leukosialin/sialophorin), the negatively charged sialoglycoprotein of leukocytes, in the binding of mycobacteria to host cells. CD43-transfected HeLa cells bound Mycobacterium avium, but not Salmonella typhimurium or Shigella flexneri. Quantitative bacteriology showed that macrophages (M(phi)) from wild-type mice (CD43(+/+)) bound M. avium, Mycobacterium bovis (bacillus Calmette-Guérin), and Mycobacterium tuberculosis (strain H37Rv), whereas M(phi) from CD43 knockout mice (CD43(-/)-) did not. Fluorescence microscopy demonstrated that the associated M. avium had been ingested by the CD43(+/+) M(phi). The inability of CD43(-/)- M(phi) to bind M. avium could be restored by addition of galactoglycoprotein (Galgp), the extracellular mucin portion of CD43. The effect of Galgp is not due to opsonization of the bacteria, but required its interaction with the M(phi) other mucins had no effect. CD43 expression by the M(phi) was also required for optimal induction by M. avium of tumor necrosis factor (TNF)-alpha production, which likewise could be reconstituted by Galgp. In contrast, interleukin (IL)-10 production by M. avium-infected M(phi) was CD43 independent, demonstrating discordant regulation of TNF-alpha and IL-10. These findings describe a novel role of CD43 in promoting stable interaction of mycobacteria with receptors on the M(phi) enabling the cells to respond specifically with TNF-alpha production.
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Affiliation(s)
| | - N. Manjunath
- The Center for Blood Research, Harvard Medical School, Boston, Massachusetts 02115
| | - Robert D. Arbeit
- Department of Medicine, Veterans Administration Medical Center and Boston University School of Medicine, Boston, Massachusetts 02118
| | - Claudio Carini
- Department of Tropical Public Health, Harvard School of Public Health, Boston, Massachusetts 02115
| | - Thomas A. Gerken
- W.A. Bernbaum Center for Cystic Fibrosis Research, Department of Pediatrics, and the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Blair Ardman
- Department of Pathology, Tufts University, and the Department of Medicine, Tupper Research Institute, New England Medical Center Hospitals, Boston, Massachusetts 02111
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Abstract
Human monocyte/neutrophil elastase inhibitor (MNEI) is a specific inhibitor of the neutrophil azurophil granule proteases including elastase. To understand the physiological mechanisms that regulate expression of MNEI, we dissected a 1.0 kb region upstream of exon 1. On transient transfection, promoter activity of MNEI-luciferase constructs was highest in U937 myeloid cells, followed by K562 hematopoietic cells, followed by HeLa cervical carcinoma cells, indicating that the MNEI promoter is most active in myeloid cells and is also active in non-myeloid cells. Three transcription factor binding elements, which confer the majority of activity, are located within the first 180 base pairs of the promoter, one of which, located at -128, was active in U937 and K562 cells but inactive in non-myeloid HeLa cells. The three proximal elements were identified by transient transfection, mutation, gel shift and competition assays as Sp1 at -170, PU.1/Spi-1 at -128, and Sp1 at -66. The trans-acting factors that bind and control these elements were detected, and their identity confirmed by antibody supershift assays. Further upstream at -821, an additional regulatory element was identified controlled by NF-kappaB, which supports the highest levels of MNEI transcriptional activity. In U937 cells, reporter gene expression by the MNEI-luciferase construct that included the NF-kappaB element was two- to three-fold greater than the construct without the element. In addition, treatment of myeloid cells with lipopolysaccharide, a complex glycolipid of gram-negative bacteria, activated NF-kappaB to bind the -821 element, together suggesting that enhancement of expression of the anti-inflammatory MNEI gene is linked to innate immune responses to bacterial infection.
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Affiliation(s)
- W Zeng
- The Center for Blood Research and the Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
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45
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Shcherbina A, Rosen FS, Remold-O'Donnell E. Reply To matzdorff, kemkes-matthes and pralle. Br J Haematol 2000; 109:674. [PMID: 10886227 DOI: 10.1046/j.1365-2141.2000.01997.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- A Shcherbina
- Children's Hospital No. 9, Research Institute for Paediatric Haematology, Moscow, Russia, and Center for Blood Research and Department of Pediatrics, Harvard Medical School, 800 Huntington Avenue, Boston, MA 02115, USA
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Shcherbina A, Rosen FS, Remold-O'Donnell E. WASP levels in platelets and lymphocytes of wiskott-aldrich syndrome patients correlate with cell dysfunction. J Immunol 1999; 163:6314-20. [PMID: 10570326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Wiskott-Aldrich syndrome, an inherited blood cell disorder due to mutations of the X-chromosome gene WASP (Wiskott-Aldrich syndrome protein), was characterized originally by thrombocytopenia, immunodeficiency, and eczema. Whereas platelet dysfunction is severe and consistent, immune defects are clinically variable, ranging from negligible to life threatening. To understand this heterogeneity, we quantified WASP in PBMC and platelets, and also in neutrophils, of patients with diverse mutations. A surprisingly complex pattern of WASP expression found for lymphoid cells formed the basis for dividing the patient mutations into four groups. Group A have low WASP levels in PBMC and higher levels in EBV cell lines, as well as near normal WASP RNA levels (7 patients, most with mild disease), suggesting that group A WASP molecules are hypersusceptible to proteolysis. Group B have low WASP levels in PBMC and EBV cells and similar low RNA levels (2 patients, moderate disease). Group C have discordant expression: WASP-positive peripheral T cells and WASP-negative peripheral B cells and EBV cell lines (9 patients, variable disease severity). Noteworthy among group C kindred are several instances of B cell lymphomas. In group D, PBMC and EBV cell lines are WASP negative (7 patients, severe disease). In contrast to the complex lymphoid cell expression patterns, all patient platelets examined were WASP negative (18 diverse patients). WASP absence in platelets provides an apparent molecular explanation for the universally severe platelet dysfunction in this disease, and the cumulative lymphoid cell findings suggest that WASP levels play a substantial role in determining immune outcome.
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Affiliation(s)
- A Shcherbina
- The Center for Blood Research and the Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
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47
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Fabbi M, Geginat J, Tiso M, Ramarli D, Parent D, Bargellesi A, Remold-O'Donnell E. 8B4/20, a private CD43 epitope on developing human thymocytes, is involved in thymocyte maturation. J Immunol 1999; 163:5964-70. [PMID: 10570283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The 8B4/20 Ag is a 120-kDa molecule whose expression on human thymocytes varies according to the differentiation stage: high density on immature CD3-/low thymocytes, reduced density on CD3medium and double-positive thymocytes, and absent on CD3high and single-positive thymocytes and on circulating T cells. In this paper we present immunological and biochemical evidence demonstrating that 8B4/20 Ag is a variant of CD43. We show that 8B4/20-expressing molecules, which are a subset of the CD43 molecules on thymocytes, are heterogeneous in charge, suggesting varying sialylation levels. The 8B4/20 epitope was mapped to the peripherally exposed N-terminal region of CD43, and the 8B4/20 antigenic determinant was characterized by requirement for the sialic acid exocyclic polyhydroxyl side chain, a feature shared with ligands of CD22. Altogether, 8B4/20-CD43 expression pattern and biochemical characteristics suggest its participation in carbohydrate-based interactions in the thymus. We therefore used specific Ab to mimic putative 8B4/20 interactions with natural ligand and examined the effect on isolated thymocytes. Treatment with 8B4/20 had no effect on in vitro apoptosis of isolated thymocytes. In contrast, 8B4/20 ligation enhanced the conversion of isolated thymocytes to differentiated phenotypes. Increased numbers were found in 8B4/20-treated cultures of CD3high and single-positive thymocytes and decreased numbers of CD3-/low and double-positive thymocytes, strongly suggesting that engagement of 8B4/20 delivers a positive signal that favors completion of the thymocyte maturation program. The ability of 8B4/20 mAb to drive thymocyte maturation in vitro suggests that CD43 molecules bearing the 8B4/20 epitope participate in early events of thymic selection.
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Affiliation(s)
- M Fabbi
- Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
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48
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Abstract
The Wiskott-Aldrich syndrome (WAS) is a severe X-linked platelet/immunological disorder arising from mutations of the gene WASP. At the clinical level, the major platelet abnormalities are small size and low number, both partially correctable by splenectomy. To identify underlying pathological events, we examined WAS platelets at various stages of their lifetime. In spleen sections from WAS patients, fluorescence microscopy showed dramatic co-localization of markers of platelets (CD41) and macrophages (CD68) compared to non-thrombocytopenic controls, suggesting that WAS splenic macrophages are involved in platelet removal. Study of isolated WAS blood platelets by flow cytometry showed substantial enhancement of surface exposure of phosphatidylserine (PS), a signal for engulfment by macrophages. Isolated resting WAS platelets were also aberrantly susceptible to microparticle release, and plasma samples of WAS patients contained > 5 times normal numbers of platelet-derived microparticles which may explain the small size of circulating platelets. Measurements with the Ca2+ sensitive dye fluo-3 revealed significantly increased Ca2+ levels, 310 +/- 13 nmol/l for WAS platelets versus 106 +/- 12 nmol/l for normal platelets, and also prolongation of agonist-induced Ca2+ flux. Cumulatively, these studies identify abnormal events occurring in WAS platelets: increased Ca2+ levels and enhancement of two Ca2+ dependent processes, PS exposure and microparticle release; these abnormal events may contribute to the in vivo decrease of platelet number and reduction of platelet size in this disease.
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Affiliation(s)
- A Shcherbina
- Center for Blood Research, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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Shcherbina A, Bretscher A, Rosen FS, Kenney DM, Remold-O'Donnell E. The cytoskeletal linker protein moesin: decreased levels in Wiskott-Aldrich syndrome platelets and identification of a cleavage pathway in normal platelets. Br J Haematol 1999; 106:216-23. [PMID: 10444190 DOI: 10.1046/j.1365-2141.1999.01508.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The Wiskott-Aldrich syndrome (WAS) is a severe disease of platelets (small size, thrombocytopenia) and lymphocytes (immunodeficiency) arising from mutations of the X-chromosome gene WASP. Because of the prominent role of cytoskeletal abnormalities, particularly the paucity of surface microvilli, in the cellular pathology of this disease, blood cells from WAS patients were examined for moesin, a cytoskeletal linker protein that stabilizes cell surface microvilli, filopodia and lamellipodia. Comparison of patient and normal lymphocytes by immunofluorescence microscopy and immunoblotting showed normal levels and distribution of moesin in lymphocytes of WAS patients. In contrast, platelets from WAS patients stained only dimly for moesin relative to normal platelets. Quantitation by immunoblot revealed significantly decreased moesin levels in WAS patient platelets relative to normal platelets (63.5 +/- 4.9% of normal levels, n = 8, P < 0.0001). A novel reaction of normal platelets was discovered that may play a role in the depletion of moesin in patient platelets, namely the cleavage of moesin as a late event in platelet activation in response to certain platelet agonists.
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Affiliation(s)
- A Shcherbina
- The Center for Blood Research and the Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
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50
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Shcherbina A, Remold-O'Donnell E. Role of caspase in a subset of human platelet activation responses. Blood 1999; 93:4222-31. [PMID: 10361119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
Platelets function to protect the integrity of the vascular wall. A subset of platelet activation responses that are especially important for thrombus formation include exposure of phosphatidylserine and release of microparticles, which generate procoagulant surfaces. The resemblance of these platelet activation processes to events occurring in nucleated cells undergoing apoptosis suggests a possible role for caspases, which are major effector enzymes of nucleated cell apoptosis. We demonstrate here the presence of caspase-3 in human platelets and its activation by physiological platelet agonists. Using cell-permeable specific inhibitors, we demonstrate a role for a caspase-3-like protease in the agonist-induced (collagen plus thrombin or Ca2+ ionophore) platelet activation events of phosphatidylserine exposure, microparticle release, and cleavage of moesin, a cytoskeletal-membrane linker protein. The role of caspase-3 in platelet activation is restricted rather than global, because other activation responses, alpha granule secretion, shape change, and aggregation were unaffected by caspase-3 inhibitors. Experiments with two classes of protease inhibitors show that caspase-3 function is distinct from that of calpain, which is also involved in late platelet activation events. These findings show novel functions of caspase and provide new insights for understanding of platelet activation.
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Affiliation(s)
- A Shcherbina
- The Center for Blood Research and the Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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