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1 Have We Missed A Role For Neutrophils In Asthma? In Steroid-Refractory Asthma? Erwin W. Gelfand, MD Chairman, Department of Pediatrics National Jewish Health Professor of Pediatrics and Immunology University of Colorado Denver, Colorado

2 Disclosures Dr. Gelfand discloses that he is on the advisory board for Boehringer Ingelheim

3 Neutrophils May Play a Role in Asthma A Steroid-Insensitive Cell Type

4 Development of Airway Allergic Responses Hawrylowicz and O Garra 2005

5 16 Number of Subjects % Change in FEV Martin RJ, et al., J Allergy Clin Immunol 119:73-80, 2007

6 Reasons for Failure to Achieve Control Compliance Asthma heterogeneity Wrong diagnosis Wrong target Failure to deliver drug to the target site Insensitivity of the pathway or target cell to corticosteroids

7 Membrane Phospholipids LTA 4 Hydrolase cpla 2 Arachidonic Acid Leukotriene B 4 BLT 1 receptor Neutrophil chemoattraction Monocyte migration Trafficking of T-cells 5-Lipoxygenase FLAP 5-HPETE 5-HETE 5-oxo-ETE Leukotriene A 4 5-Lipoxygenase LTC 4 Synthase Leukotriene C 4 Leukotriene D 4 Leukotriene E 4 CysLT 1 receptor OXE receptor Bronchoconstriction Mucus secretion Eosinophil chemoattractant Neutrophil monocyte migration Neutrophil activation Vascular permeability Airway smooth muscle contraction Eosinophil infiltration

8 Asthma Neutrophils LTB4 BLT1 Many Factors Neutrophils Asthma Mast Cells LTB4 BLT1 Many Factors

9 Increased recruitment Receptors BLT1 LTB4 Airway Neutrophilia CXCR2 Chemokines Epithelial cell-derived potent chemoattractants IL-8 MIP-2 KC

10 Increased survival Airway Neutrophilia Inhibit neutrophil apoptosis IL-13 TNF GM-CSF G-CSF IFN

11 Corticosteroids Increased release of neutrophils from bone marrow Enhance neutrophil survival

12 Bronchoconstriction Neutrophil adhesion TXA 2 MPO Cytotoxicity Mast cells Histamine Platelets Serotonin EARLY RESPONSE Transmigration of neutrophils Adhesion molecules ROS Cytotoxicity IL-8 Mucus hypersecretion Elastase Cytotoxicity Vascular permeability Mucus hypersecretion Bronchial hyperreactivity Release of ECP Monteseirin J, J Invest Allergolog Clin Immunol 19: , 2009

13 Neutrophil-Derived Serine Proteinases/Defensins Affect epithelial integrity Mucin secretagogues Goblet cells Submucosal gland cells Vascular permeability Airway hyperresponsiveness

14 Inflammatory Cell Composition in Eosinophils Neutrophils Mixed Pauci-cellular Asthmatic Airways

15 Are there distinct asthma phenotypes?

16 Asthma can be divided into at least two distinct molecular phenotypes defined by the degree of Th2 inflammation! Woodruff PG et al., AJRCCM 180: , 2009

17 Eosinophilic and Neutrophilic Eosinophilic Asthma Inflammation in Asthma Thickening of basement membrane zone Corticosteroid responsive Neutrophilic Asthma More severe airflow (low post BD FEV1 obstruction) Severe disease Relatively corticosteroid unresponsive Fahy JV, Proc Am Thorac Soc 6: , 2009

18 Woodruff PG et al., AJRCCM 180: , 2009

19 Analysis of Sputum Eosinophils in Mild-To-Moderate Asthma No ICS ICS McGrath et al., AJRCCM 185:612, 2012

20 Conclusions A sizeable subgroup of mild-to-moderate asthma has a disease phenotype that is not the usual eosinophilic, steroid-responsive subtype, but a different subtype whose mechanisms are poorly understood and for which new controller treatments are needed McGrath et al., AJRCCM 185:612, 2012

21 Shaw et al, Chest 132: , 2007

22 Steroid Insensitivity Neutrophils CD8 T cells Th17 cells Mast cell / basophil degranulation Antibody production

23 Steroid Insensitivity Neutrophils Steroid Insensitive Pathways Initiated by Certain Triggers

24 pg/ml Mediators in Wheezing Children (WC) Compared to Normal Controls (NC) p=0.04 WC NC WC NC LTE4 LTB4 p=0.05 Krawiec ME; AJRCCM 163:1338, 2001

25 LTE4 and Smoking in Asthma Conclusion: Urine LTE4 increases with smoking Gaki Resp. Med 2006

26 Asthma Pathogenesis Trigger Predominant Pathway Predominant Cell Type Allergen Exposure Virus Infection Diesel Exhaust/ Ozone Smoking Th2, IgE Th1, LT LT LT Eosinophils CD4 T cells Neutrophils CD8 T cells Neutrophils CD8 T cells Neutrophils CD8 T cells

27 My Patients Asthma Does Not Appear to Respond to Corticosteroids: Why? It s all about the the Trigger! Allergen Virus Air quality ASTHMA Tobacco smoke Triggers activate pathways and pathways define corticosteroid sensitivity!

28 Steroid Insensitivity Neutrophils CD8 T cells Th17 cells Mast cell / basophil degranulation Antibody production

29 Lloyd and Hessel, Nature Rev. Immunol. 10: , 2010

30 Th1 T-bet Th2 GATA3 Th17 RORC IFN- LT- IL-4 IL-5 IL-9 IL-13 IL-17A IL-17F IL-22 Activity on: Protection from: Involved in: Macrophages NK cells B cells Eosinophils Mast cells Basophils B cells Neutrophils Macrophages B cells Intra cellular bacteria, fungi, protozoa Extracellular parasites Chronic inflammatory disorders Autoimmune disorders? Asthma Atopic disorders Chronic inflammatory Extracellular disorders bacteria, fungi Autoimmune disorders Cosmi L, et al, Allergy? Asthma 66: , 2011 Cosmi L, et al, Allergy 66: , 2011

31 Asthma Pathogenesis Trigger Predominant Pathway Predominant Cell Type Allergen Exposure Virus Infection Diesel Exhaust/ Ozone Smoking Th2, IgE Th1, LT LT LT Eosinophils CD4 T cells Neutrophils CD8 T cells Th17 Neutrophils CD8 T cells Th17 Neutrophils CD8 T cells Th17

32 Adaptive Immunity (Allergic) Asthma Innate Immunity (Non-Allergic)

33 Adaptive Immunity (Allergic) T cells (Th2, Tc2) Eosinophils Asthma ILC1 Innate Immunity (Non-Allergic) ILC2 IL-17 ILC3 Neutrophils

34 Pathways Leading to Airway Pathology GENES IL-25 IL-33 TSLP Th2 IL-5 IL-13 DC IL-8 Neutrophils IL-25 IL-33 TSLP Innate Cells (ILC2) IL-5 IL-13 ILC3 IL-17 ENVIRONMENTAL TRIGGERS AHR AIRWAY INFLAMMATION Neutrophils

35 Chesne J, et al, Amer Resp Crit Care Med 190: , 2014

36 Busse W, et al, Amer J Resp Crit Care Med 188: , 2013

37 Papp KA, et al, J. Invest. Derm. 132: , 2012

38 Airway Neutrophilia Friend or Foe?

39 Neutrophils Release Foe! Reactive oxygen species Cytokines Lipid mediators Enzymes Elastic Cathepsin G Myeloperoxidase Non-enzymatic defensins

40 Neutrophils - Friend Key immune defense cell BUT, even in death have important immunomodulatory activities

41 Resolution of Inflammation in Asthma Inflammation resolution involves subsets of inflammatory cells, such as alternatively activated or M2 macrophages, that possess specific functional characteristics related to suppressing inflammation and cleaning up cellular debris.

42 Resolution of Inflammation in Asthma Processes are mediated by: Anti-inflammatory cytokines Lipoxygenase-derived bioactive lipids Transcription factors

43 Resolution of Inflammation in Asthma Successful resolution of inflammatory disease processes, often referred to as catabasis, requires a distinct series of processes: Inhibition of inflammatory cell recruitment Promotion of inflammatory cell egress Clearance of apoptotic cells (efferocytosis)

44 Anti-Inflammatory Potential of Apoptotic Neutrophils Apoptotic neutrophils are quiescent Secretory processes shut down Provides important anti-inflammatory stimulus to other cells Resolution of inflammation Eat me signals other phagocytic cells M2 macrophages IL-10

45 Ortega-Gomez A, et al, EMBO Mol Med 5: , 2013

46 FOE FRIEND Toxic Mediators Enhance Asthma Pathobiology Neutrophils Neutrophil Necrosis Neutrophil Apoptosis

47 FOE Toxic Mediators Enhance Asthma Pathobiology Neutrophils Neutrophil Necrosis Neutrophil Apoptosis Resolution of Inflammation FRIEND Phagocytosis of Pathogens Protect Host

48 Driving Neutrophil Apoptosis to CDK inhibitors ERK1/2 inhibitors Bax inhibition PI3K inhibition Resolve Inflammation

49 Do Neutrophils Play a Role in Severe Asthma in Severe Asthma? A large percentage of patients with severe asthma demonstrate airway neutrophilia Neutrophils are not only steroid-insensitive but corticosteroids may prolong their survival and increase bone marrow release. Their role in contributing to a severe asthma endotype is unclear. Their role in defending against pathogens is clear. Neutrophils and neutrophil apoptosis may be an essential component for resolution of inflammation.