Neutrophils in the Pathogenesis of Sepsis

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1 Neutrophils in the Pathogenesis of Sepsis John C. Marshall, MD FRCSC St. Michael s Hospital Critical Care Canada Forum 2012 Toronto, Canada October 29, 2012 University of Toronto

2 Thanks to Songhui Jia Maria Jimenez Yue Li Zeenat Malam Jean Parodo Ravi Taneja Jennifer Tsang Bill Watson

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5 Neutrophils are a Dynamic Population Constitutively apoptotic 6 8 Hours In vivo Hours In vitro PMN released and die by apoptosis each day

6 Neutrophils kill bacteria and phagocytose damaged tissue Activated neutrophils also damage adjacent normal tissues

7 Neutrophil Antimicrobial Defenses Antimicrobial peptides Production of reactive oxygen intermediates BPI Defensins Alkaline phosphatase Lysozyme Lactoferrin Elastase Cathepsin G

8 Neutrophil extracellular traps (NETs)

9 Log CFU/ml Blood 8 Non-specific IgG * Anti-PMN 6 4 ** Hours + 12 Hours Time Relative to CLP Time-dependent Effects of Neutrophil Depletion in CLP - Hoesel et al Shock 24:40, 2005

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11 Percent Apoptosis PMN Apoptosis is Delayed in Sepsis Control LPS Sepsis 20 * 10 ** 0 0 Hours 18 Hours 24 Hours Duration of In Vitro Culture - Taneja, Crit Care Med 32:1460,2004

12 Factors Inhibiting Neutrophil Apoptosis Microbial Products Host-derived Mediators Endotoxin Interleukin (IL)-1β Lipoteichoic acid IL-2 Mannan IL-3 Modulins from CONS IL-4 E. coli verotoxin IL-6 H. pylori surface proteins IL-8 Butyric acid Tumor Necrosis Factor Propionic acid Interferons G-CSF, GM-CSF Respiratory syncytial virus Leptin PBEF C5a Cathelicidins Physiologic Processes Transendothelial migration

13 % Apoptosis Delayed Apoptosis Requires Cellular Activation and Protein Synthesis 40 - Watson, J.Immunol. 161:957, * * Control Herb A PDTC CHX 0 Control LPS (1mg/ml) GM-CSF (100U/ml)

14 Percent Apoptosis Effects of Anti-sense to IL-1 on LPS and GM-CSF Inhibition of PMN Apoptosis Control LPS (1ug/ml) GM-CSF (100U/ml) 10 0 Control Anti-sense Sense Anti-sense + IL-1 - Watson, J.Immunol. 161:957, 1998.

15 Pre-B Cell Colony Enhancing Factor (PBEF) 52 kda secreted protein Cytokine-like TATT motifs in mrna Synergizes with IL-7 to induce pre-b cell colony formation - Samal; Mol.Cell Biol. 14:1431, 1994

16 PBEF mrna is Highly Expressed in Sepsis PMN Sepsis Patients Lps Con PBEF G3PDH - Jia et al J Clin Invest 113:1318, 2004

17 Percent Apoptosis PBEF Anti-sense Partially Restores PMN Apoptosis in Sepsis * No Oligo Sense Non-sense Anti-sense - Jia et al J Clin Invest 113:1318:2004

18 % apoptosis Anti-apoptotic effect of Nampt active PBEF on trauma PMN is inhbited by prior addition of insulin (20 µu/ml) N= no insulin add ins 2nd add ins 1st 0 Control PBEF S199A S200A

19 Hotchkiss et al Crit.Care Med. 28:3207, 2000 Trauma and Sepsis Result in Systemic Epithelial Cell Apoptosis - Imai et al, JAMA 289:2104, 2003

20 CD95/TNFR Caspase 8 Cytochrome C APAF-1 Procaspase 9 Inhibitors of Apoptosis: Survivin CIAP1,2 XIAP1, NAIP Bcl2 Mcl1 Caspase 3 DNA, Protein cleavage SMAC/Diablo

21 Caspase-8 MDFSRNLYDIGEQLDSEDLASLKFLSLDYIPQRKQEPIK DALMLFQRLQEKRMLEESNLSFLKELLFRINRLDLLITYL NTRKEEMERELQTPGRAQISAYRFHFCRMSWAEANSQ CQTQSVPFWRRVDHLLIRVMLYQISEEVSRSELRSFKF LLQEEISKCKLDDDMNLLDIFIEMEKRVILGEGKLDILKR VCAQINKSLLKIINDYEEFSKGEELCGVMTISDSPREQD SESQTLDKVYQMKSKPRGYCLIINNHNFAKAREKVPKL HSIRDRNGTHLDAGALTTTFEELHFEIKPHDDCTVEQIY EILKIYQLMDHSNMDCFICCILSHGDKGIIYGTDGQEAPI YELTSQFTGLKCPSLAGKPKVFFIQACQGDNYQKGIPV ETDSEEQPYLEMDLSSPQTRYIPDEADFLLGMATVNNC VSYRNPAEGTWYIQSLCQSLRERCPRGDDILTILTEVNY EVSNKDDKKNMGKQMPQPTFTLRKKLVFPSD

22 Trauma Neutrophils Induce Caspase-8 Dephosphorylation and Apoptosis of A549 Lung Epithelial Cells ** ** Western: ~ Caspase-8 ~py No PMN + PMN DPI Catalase GSH Percent Hypodiploid DNA * * A549 HEK293

23 The Caspase-8 Survivalsome CD95/TNFR IL-1R FADD SHP-1 Pro-caspase-8 Caspase-8 Dephosphorylation py py lyn Caspase-8 Phosphorylation p18 p10 Cleavage of caspase-3 and progression of apoptosis PI3 Kinase Activation PBEF Transcription IAP Synthesis

24 Percentage Apoptosis Phagocytosis of Candida albicans Induces Neutrophil Apoptosis In Vitro Control 1 : 1 5 : 1 10 : 1 Candida : Neutrophil Ratio * - Rotstein, Shock 2000; 14:278

25 Intratracheal E. coli Attenuates Pulmonary Neutrophilia Ischemia/reperfusion I/R + E. coli - Sookhai, Ann Surg 2002; 235:285

26 Percent Survival Intratracheal Heat-killed E. coli Attenuates Mortality Following Ischemia/Reperfusion Sham I/R + E.coli I/R + Saline Time (Hours) - Sookhai Ann Surg 2002; 235:285

27 Conclusions Functional neutrophils are critical to the early response against infection Their prolonged activity contributes to inadvertent organ injury Accelerating their involution through apoptosis may limit this delayed harm

28 Thank you!!