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Allan Tsung, MD Department of Surgery University of Pittsburgh
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Our Immune System at Work Organ Dysfunction Infection Injury
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Immune Activation Organ Dysfunction Systemic Inflammatory Response Infection Injury PAMPs+ Receptors (e.g. TLRs)
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Classes of Molecules That Initiate The Innate Immune Response Damage-associated Molecular Patterns (DAMPs): Endogenous molecules that are normally unavailable to the immune system that are released and recognized by immune cells following tissue injury. Pathogen-associated Molecular Patterns (PAMPs): Exogenous molecules expressed or released by invading microorgansims that are structurally unique to the pathogen.
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Sources of Endogenous Danger Signals (Damage Associate Molecular Pattern (DAMP) Molecules) Damaged or Dying Cells Secreted From Stressed Cells Degradation of Tissue Matrix DAMPs Pattern Recognition Receptor PMN Protease
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DAMP-TLR Interactions: DAMP Molecular Classification Piccinini & Midwood, 2010
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Extracellular Functions of HMGB1
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Hepatocyte Ischemia- Reperfusion TLR4 HDACs HATs HMGB1 Acetyl-HMGB1 Kupffer Cell or Dendritic Cell PMNs Inflammatory cell activation, differentiation, and infiltration ROS Ca + 2 CaMKs
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http://www.fastbleep.com/biology-notes/40/116/1191
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What is the role of histones in liver I/R injury? ClampClamp Ischemia time Reperfusion time Clamp removed removedClamp 1hr1hr 6hr6hr
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* P<0.05 * * *
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Sham 40× Liver I/R 40× Sham 40× Liver I/R 40× Histone-red Nuclei-blue Actin-green
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0 1 3 6 12 24 48 Hypoxia (1%) H3 H4 17kDa 11kDa Histone H3 Hypoxia Histone H3 Normoxia Histone H4 Hypoxia Histone H4 Normoxia Histone-green Nuclei-blue Actin-red
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* * * P<0.05
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Sham IgG Anti-H4 Anti-H3 18.7±4.5% 5.8±2.6% 6.7±2.1%
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* * * * * P<0.05
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* * * PBS Histone 13±7% 50±10%
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P-p38 Total-p38 Sham I/R PBS I/R Histone P-JNK Total-JNK P-ERK Total-ERK
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Which pattern recognition receptor is involved in histone signaling pathway in liver I/R?
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recognizes both bacterial DNA rich in unmethylated CpG motifs and endogenous DNA from mammalian cells Tian J et al. Nat Immunol.2007 Klinman DM. Nat Rev Immunol.2004
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* P<0.05 * * *
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Extracellular Intracellular NPC Ischemic hepatocyte Endosome TLR9 MyD88 IRAK TRAF6 P JNK/P38/ERK AP1 P IRF7 IKK complex P IκBIκBNFκB Pro-inflammatory gene expression Histones Huang H et al. Hepatology 2011
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Besides MAPK and NF-κB mediated cytokine production, do histones activate other inflammatory signaling pathway during liver I/R injury?
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Davis BK. et al. Annu Rev Immunol 2011 Inflammasome is a cytosolic multi-protein complex The sensor protein (NLRP3) The adaptor protein ASC The inflammatory protease caspase-1 Activated form senses a diverse range of microbial and non-microbial cellular stress and damages Platform of activating caspase-1, cleaves the biologically inactive precursors of IL-1β and IL-18
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* * * P<0.05
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Do histones activate the NLRP3 inflammasome in liver I/R? Do histones activate the NLRP3 inflammasome in liver I/R?
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Histones Sham Histones PBS I/R Casp-1p20 Cleaved IL-1β Cleaved IL-18 β-actin
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Anti- histone H3 Anti- histone H4 Casp-1p20 Cleaved IL-1β Cleaved IL-18 IgG Sham I/R β-actin Liver I/R Anti-histones Ab
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N.S.
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shamLiver I/R WT TLR9 KO WTTLR9 KO PBSHistones PBS Histones Casp-1 p20 Cleaved IL-1β Cleaved IL-18 β-actin Histones TLR9
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What liver cell types mediate histone activation of the Inflammasome in liver I/R? What liver cell types mediate histone activation of the Inflammasome in liver I/R? Parenchymal cells (e.g. Hepatocytes) Bone-marrow derived cells (e.g. Kupffer cell, Neutrophils, Dendritic cell)
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Steiner AA, et al. Blood 2005 Caspase-1 KO Caspase-1 WT WT/WT WT/KOKO/WT KO/KO
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WT/WT KO/WT WT/KO KO/KO Cleaved IL-1β Cleaved IL-18 β-actin * *
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Histones (μg/mL) 0 5 25 50 Casp-1 p20 β-actin Cleaved IL-1β Cleaved IL-18 PBS Histones Merge Activated caspase-1 +Actin
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Kupffer cells NLRP3 ASC TXNIP TRX TLR9 Histones MyD88 Endosome JNK P ROS NF-κB Pro-IL-1β Transcription Pro- caspase-1 Activated- caspase-1 IL-1β Ischemic Hepatocytes Pro-IL-18 IL-18 Innate immune cells recruitment Dendritic cells Inflammatory monocytes Neutrophils IL-6 TNF-α Huang H et al. Journal of Immunology 2013
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Hai Huang Doris Chen John Evankovich Gary Nace Timothy Billiar Charles Esmon Donna Stolz Xinhua Liao Nicole Hays NIHHHMI Society of University Surgeons
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