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Role of serpinB1 in cellular homeostasis in the bone marrow and the lung

English title Role of serpinB1 in cellular homeostasis in the bone marrow and the lung
Applicant Benarafa Charaf
Number 127464
Funding scheme Project funding (Div. I-III)
Research institution Theodor Kocher Institut Universität Bern
Institution of higher education University of Berne - BE
Main discipline Immunology, Immunopathology
Start/End 01.10.2009 - 31.12.2012
Approved amount 317'853.00
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All Disciplines (3)

Discipline
Immunology, Immunopathology
Biochemistry
Cellular Biology, Cytology

Keywords (6)

Neutrophils; Proteases; Serpins; Apoptosis; Inflammation; Lung

Lay Summary (English)

Lead
Lay summary
Neutrophils are blood cells that are rapidly recruited to sites of inflammation and infection. These cells carry a wide range of antimicrobial enzymes and molecules stored in granules. The activity of these proteins is required to kill invading pathogens and to mount an inflammatory response. However, in circumstances where excessive inflammation occurs, these proteins turn against the host by destroying protective molecules and by inducing an inflammatory vicious cycle that can be fatal to the host. This excessive neutrophilic response is a hallmark of pulmonary inflammation in cystic fibrosis and chronic obstructive pulmonary disease. Among the neutrophil weapons that have this dual protective/pathologic role are neutrophil serine proteases, potent enzymes that hydrolyze other proteins. While these proteases directly kill microbes that have been taken up by neutrophils, they have pathologic functions by fueling the inflammatory response and by destroying extracellular matrix proteins and immune defense proteins. The regulation of neutrophil proteases by specific inhibitors is therefore crucial in maintaining homeostasis. The proposed studies aim to increase understanding of the role of neutrophil proteases and their inhibitor SerpinB1 in inflammation, infection and homeostasis. SerpinB1 is a member of the serpin (SERine Protease INhibitor) family of proteins and is arguably one of the best inhibitors of the neutrophil serine proteases, including neutrophil elastase, cathepsin G and proteinase-3. We have previously shown that serpinB1 preserves the innate immune response to lung bacterial infection by protecting neutrophils from an early death and by inhibiting the destruction of protective molecules found in the lung. Building on these findings, we will investigate the role of serpinB1 in neutrophil and lung cell homeostasis in steady state and during inflammatory injury. Overall, these studies will provide significant advances in understanding the regulation of neutrophil serine proteases in health and disease and may lead to the identification of new targets for therapeutic intervention.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
SerpinB1 deficiency is not associated with increased susceptibility to pulmonary emphysema in mice
Cremona T.P., Tschanz S.A., von Garnier C., Benarafa C. (2013), SerpinB1 deficiency is not associated with increased susceptibility to pulmonary emphysema in mice, in American Journal of Physiology - Lung Cellular and Molecular Physiology, 305(12), L981-L989.
SerpinB1 is critical for neutrophil survival through cell-autonomous inhibition of cathepsin G
Baumann M., Pham C.T., Benarafa C. (2013), SerpinB1 is critical for neutrophil survival through cell-autonomous inhibition of cathepsin G, in Blood, 121(19), 3900-3907.
Increased surfactant protein D fails to improve bacterial clearance and inflammation in serpinB1-/- mice.
Stolley J Michael, Gong Dapeng, Farley Kalamo, Zhao Picheng, Cooley Jessica, Crouch Erika C, Benarafa Charaf, Remold-O'Donnell Eileen (2012), Increased surfactant protein D fails to improve bacterial clearance and inflammation in serpinB1-/- mice., in American journal of respiratory cell and molecular biology, 47(6), 792-9.
Critical role of serpinB1 in regulating inflammatory responses in pulmonary influenza infection.
Gong Dapeng, Farley Kalamo, White Mitchell, Hartshorn Kevan L, Benarafa Charaf, Remold-O'Donnell Eileen (2011), Critical role of serpinB1 in regulating inflammatory responses in pulmonary influenza infection., in The Journal of infectious diseases, 204(4), 592-600.
DNase 2 is the main DNA-degrading enzyme of the stratum corneum.
Fischer Heinz, Scherz Jennifer, Szabo Sandra, Mildner Michael, Benarafa Charaf, Torriglia Alicia, Tschachler Erwin, Eckhart Leopold (2011), DNase 2 is the main DNA-degrading enzyme of the stratum corneum., in PloS one, 6(3), 1-9.
SerpinB1 protects the mature neutrophil reserve in the bone marrow.
Benarafa Charaf, LeCuyer Tessa E, Baumann Mathias, Stolley James Michael, Cremona Tiziana P, Remold-O'Donnell Eileen (2011), SerpinB1 protects the mature neutrophil reserve in the bone marrow., in Journal of leukocyte biology, 90(1), 21-29.
The SerpinB1 knockout mouse a model for studying neutrophil protease regulation in homeostasis and inflammation.
Benarafa Charaf (2011), The SerpinB1 knockout mouse a model for studying neutrophil protease regulation in homeostasis and inflammation., in Methods in enzymology, 499, 135-148.

Collaboration

Group / person Country
Types of collaboration
Harvard Medical School, Boston United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Washington University, St Louis, MO United States of America (North America)
- Publication
Medical University of Vienna, Vienna Austria (Europe)
- Publication
Institute of Pharmacology, University of Bern Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Annual Congress of the European Respiratory Society Talk given at a conference Impact of cigarette smoke exposure on Pseudomonas clearance in serpinb1-/- mice 01.09.2012 Vienna, Austria Cremona Tiziana;
11th Bern Summer-School Inflammation, Immunomodulation, Inspiration Poster Maturation arrest and cell death induced by sustained expression of BCL2 in neutrophils 12.08.2012 Bönigen, Switzerland Baumann Mathias; Benarafa Charaf;
1st International Symposium, Neutrophil in immunity Poster Cathepsin G and serpinB1 regulate neutrophil survival and homeostasis 09.06.2012 Québec, Canada Benarafa Charaf; Baumann Mathias;
44th Annual Meeting of the Society for Leukocyte Biology Talk given at a conference SerpinB1 and Cathepsin G Regulate Neutrophil Homeostasis in a Cell-Autonomous and Caspase-Independent Death Pathway 22.09.2011 Kansas City, United States of America Benarafa Charaf;
10th Bern Summer-School Inflammation, Immunomodulation, Inspiration Poster Impact of cigarette smoke exposure on Pseudomonas clearance in serpinB1-/- mice 21.08.2011 Sigriswil, Switzerland Cremona Tiziana; Benarafa Charaf;
98th Annual Meeting of the American Association of Immunologists Talk given at a conference SerpinB1 inhibition of cathepsin G is critical for neutrophil survival and the maintenance of the bone marrow reserve of mature neutrophils in vivo 13.05.2011 San Francisco, United States of America Benarafa Charaf;
22nd Meeting of the Swiss Immunology PhD students Talk given at a conference SerpinB1 inhibition of Cathepsin G is critical for neutrophil survival and the maintenance of the bone marrow reserve of mature neutrophils in vivo 30.03.2011 Wolfsberg, Switzerland Baumann Mathias;
Institute for Infectious Diseases, Seminar Series Individual talk Regulation of neutrophil proteases by serpinb1 in pulmonary diseases 11.02.2011 Institute for Infectious Diseases (IFIK), Bern, Switzerland Benarafa Charaf;
6th Swiss Apoptosis Meeting Poster SerpinB1 is critical for neutrophil survival and the maintenance of the bone marrow reserve of mature neutrophils in vitro and in vivo 30.09.2010 Bern, Switzerland Benarafa Charaf; Baumann Mathias;
9th Bern Summer-School Inflammation, Immunomodulation, Inspiration Talk given at a conference Serpinb1 regulates neutrophil homeostasis in vitro and in vivo 08.08.2010 Kandersteg, Switzerland Baumann Mathias;
9th Bern Summer-School Inflammation, Immunomodulation, Inspiration Talk given at a conference The role of serpinb1 in lung macrophages and epithelial cells in models of pulmonary injury 08.08.2010 Kandersteg, Switzerland Cremona Tiziana;
Lung Research Seminar Series Individual talk Role of teh serine protease inhibitor serpinb1 in pulmonary diseases 19.03.2010 Bern, Switzerland Benarafa Charaf;
Bern Immunology Club, Seminar Series Individual talk Role of the serine protease inhibitor serpinb1 in neutrophil homeostasis and inflammation 25.11.2009 University of Bern, Bern, Switzerland Benarafa Charaf;


Associated projects

Number Title Start Funding scheme
149790 Serpin regulation of leukocyte proteases in cellular homeostasis and inflammation 01.12.2013 Project funding (Div. I-III)
173137 Serpin regulation of leukocyte proteases in cellular homeostasis and inflammation 01.06.2017 Project funding (Div. I-III)

Abstract

SerpinB1 is a member of the serpin (SERine Protease INhibitor) family of proteins, which function as irreversible inhibitors of serine proteases. SerpinB1, also known as MNEI (monocyte neutrophil elastase inhibitor), is arguably one of the best inhibitors of the three neutrophil serine proteases (NSPs), including neutrophil elastase, cathepsin G and proteinase-3. NSPs are key components of the innate defenses by directly killing invading microbes, a process that is largely occuring inside phagosomes. However, as a double edged sword, NSPs can turn against the host if released in excess of inhibitors in the extracellular milieu at infection or inflammatory sites. Indeed, excess NSPs can digest extracellular matrix, destroy innate immune defense molecules and antibodies and induce the production of inflammatory mediators.To explore a physiological role for serpinB1 in controlling excess NSPs in infectious and inflammatory disease, we have generated mice deficient for serpinB1 (serpinB1-/-) by targeted mutagenesis. These mice failed to clear, and succumbed to, Pseudomonas aeruginosa lung infection. This innate immune defect was due in part to increased proteolysis of lung surfactant protein-D and to early death of lung recruited neutrophils. These findings were highly significant because (i) it demonstrated that serpinB1, a cytoplasmic inhibitor of NSPs carried at high levels in neutrophils, provides a physiological and vital shield against extracellular pathologic actions of NSPs, and (ii) it indicated that serpinB1 has an additional function in neutrophil homeostasis at inflammatory sites. Building on these findings, neutrophil development and homeostasis in the bone marrow of serpinB1-/- mice was investigated further and preliminary evidence strongly suggests that serpinB1 is required to preserve the size of the neutrophil reservoir bone marrow. In addition, preliminary data also indicate that serpinB1 has a role in protecting lung epithelial cells against excess neutrophil serine proteases.To test the hypothesis that serpinB1 provides a cytoprotective shield in neutrophils and lung epithelial cells, we will focus on the following specific aims. In specific aim 1, we will investigate the mode, pathways and timing of cell death of bone marrow neutrophils in serpinB1-/- and wild type mice in steady state granulopoiesis using in vitro culture of neutrophils and mixed bone marrow chimera. In specific aim 2A, we will test whether the size of the bone marrow reservoir affects the kinetics of neutrophil recruitment, survival and function of neutrophils during acute lung injury. In specific aim2B, we will use a transgenic approach to test the hypothesis that intracellular levels of serpinB1 directly affect the size of the bone marrow neutrophil reservoir in steady state and the mobilization of neutrophils during inflammation. In aim 3, we will explore the regulation of serpinB1 expression in human lung epithelial cell lines and investigate a cytoprotective role for serpinB1 in primary culture of lung epithelial and mesenchymal cells of WT and serpinB1-/- mice.Overall, these studies will provide highly significant advances in understanding the regulation of neutrophil serine proteases in homeostasis of neutrophils and lung inflammation.
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