Host-Pathogen Interaction. Sites of microbial infection Skin Lung Conjunctiva of eye Scratch, injury...
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Transcript of Host-Pathogen Interaction. Sites of microbial infection Skin Lung Conjunctiva of eye Scratch, injury...
Host-Pathogen Interaction
Sites of microbial infectionSites of microbial infection
Skin
Lung
Conjunctiva of eye
Scratch, injury
Insect bite
Mouth
Digestivetract
Urogenitaltract
Anus
Pores, hair Follicles,Sweat glands
Pathogenic microbes
Normal non-pathogenic microflora
Pathogens can be successful Pathogens can be successful
in causing an infectionin causing an infection
They can They can attachattach to and to and penetratepenetrate body surfaces body surfaces
Ex: Ex: Schistosoma mansoniSchistosoma mansoni
Pathogens can be Pathogens can be introducedintroduced by a by a biting insectbiting insect
Ex: Ex: Malaria, Malaria, LeishmaniaLeishmania, virus, bacteria, virus, bacteria
Pathogens can Pathogens can take advantagetake advantage of of preliminarypreliminary damagedamage (wound, respiratory tract (wound, respiratory tract damage)damage)
Ex: Ex: Trypanosoma cruziTrypanosoma cruzi
Vector: Reduviid bugs (Vector: Reduviid bugs (TriatomaTriatoma & & RhodniusRhodnius))
a.k.a. Kissing buga.k.a. Kissing bug
However, the Immune SystemHowever, the Immune Systemhas has NaturalNatural, , ConstitutiveConstitutive Microbial SensorsMicrobial Sensors Utilized to RaUtilized to Rapidly React to Invasive Pathogens.pidly React to Invasive Pathogens.
They are part of the Innate Immune Response and They are part of the Innate Immune Response and Play Pivotal Role in the Development of the Play Pivotal Role in the Development of the
Adaptive Immune Response.Adaptive Immune Response.
TLR RolesTLR Roles
O’Neill, Luke A.J. “Immunity’s Early-Warning System”. Scientific American, Jan (2005), 38-45.
O’Neill, Luke A.J. “Immunity’s Early-Warning System”. Scientific American, Jan (2005), 38-45.
TLR1TLR1
TLR2TLR2
TLR4TLR4 TLR3TLR3TLR5TLR5 TLR9TLR9
PGNPGNUnmethylateUnmethylate
ddCpG DNACpG DNA
LPSLPSdsRNAdsRNA
FlagellFlagellinin
Phagocytic
receptor
MicroorganiMicroorganismssms Antigen Presenting CellAntigen Presenting Cell
Naive Naive T T
CellCell
CD28B.7
TCRMHC
NF-NF-BB
Cytokines (IL-1, IL-6, IL-12, TNF)Chemokines (MIP-2, MIP-1/)
PeptidePeptide
LipopeptidesLipopeptides
Phagosome
TLR2TLR2
Activation of adaptive Activation of adaptive immunity by innate immunity by innate
immunityimmunity
Co-stimulatorymolecules
Rapid crystalline (0.7-0.9 m)Size and Shape similar to PfHZ(see Inset). Bar size is 200 nm.
PfHZ sPLHZ
Hemozoin: A Malarial Metabolic WasteHemozoin: A Malarial Metabolic Waste
Intracellular Microbial SensorsIntracellular Microbial Sensors
Toll-like receptors:Toll-like receptors: Membrane Receptor that Sense Membrane Receptor that Sense ExtracellularExtracellular Microbes Microbesand within and within phagosome/endosome.phagosome/endosome.
NOD-Like Receptors, RIG and MDA:NOD-Like Receptors, RIG and MDA:IntracellularIntracellular Microbial Sensors Microbial Sensors Are Are CytoplasmicCytoplasmic surveillance proteins with surveillance proteins with CARD domainCARD domain
NOD proteinsNOD proteins (Nucleotide-binding oligomerisation domain)(Nucleotide-binding oligomerisation domain) Two membersTwo members: NOD-1 and NOD-2: NOD-1 and NOD-2
RIG-1RIG-1 (Retinoid-induced gene 1)(Retinoid-induced gene 1)
MDAMDA (Melanoma differentiation-associated gene)(Melanoma differentiation-associated gene)
CARD domainCARD domain
CARDCARD ((CCaspase-aspase-AActivating and ctivating and RRecruitment ecruitment DDomain)omain)
Found in some caspase proteinsFound in some caspase proteins
Mediates Mediates protein-proteinprotein-protein interaction interaction
Bouchier-Hayes L and Martin S.J., EMBO (2002)
Helicase domain
Helicase domain
CARD CARD
RIG-I
MDA-5/HelicardCARDCARD
1
1
925
1025
CARD1 540IPS-1/Cardif/VISA/MAVS
************
************
NOD protein structureNOD protein structure
NOD-1
NOD-2
CARD NBD LRRs
N-term
N-term C-term
C-term
CARD CARD NBD LRRs
CARD (Caspase-activating and recruitment domain)Caspase-activating and recruitment domain)
NBD (Nucleotide binding Domain)Nucleotide binding Domain)
LRRs (Leucine-Rich Repeats)Leucine-Rich Repeats)
NOD ligands: PeptidoglycanNOD ligands: Peptidoglycan
Peptidoglycan (PGN)Peptidoglycan (PGN)
Major component of Major component of gram+ cell wallgram+ cell wall
Found in thin layer in Found in thin layer in periplasmic space of gram–periplasmic space of gram–
Glycan chainsGlycan chains alternating alternating GlcNAcGlcNAc and and MurNAcMurNAc
linked by peptide bridgelinked by peptide bridge
Philpott D.J. and Girardin S.E., Mol Imm (2004)
Meso-DAP
MDP
NOD signallingNOD signalling
IKK complex
IkB
NFkB
NFkB
IkB
Proteasome
PGNNOD2
NOD2
NOD1
NOD1
Transcription
RIP2
RIP2
RIP2
NOD-Like Receptors (NLRs)NOD-Like Receptors (NLRs)
NOD1/2NOD1/2 IPAF/NAIPIPAF/NAIP NALP3/ASCNALP3/ASC
BacteriaBacteria
PGNPGN PGN PGN DAP DAP (meso-diaminopimelic)(meso-diaminopimelic)
MDP MDP (muramyl dipeptide)(muramyl dipeptide) MDPMDPSalmonellaSalmonella FrancisellaFrancisellaLegionellaLegionella RNA RNA (PAMP)(PAMP)
FlagellinFlagellin ToxinsToxins
Danger-Associated Host ComponentsDanger-Associated Host Components
Uric Acid CrystalsUric Acid CrystalsHemozoin ???Hemozoin ???(metabolic waste)(metabolic waste)
NOD-1
NOD-2
Meylan et al. Nature July 2006Meylan et al. Nature July 2006
NOD-2 and Crohn’s diseaseNOD-2 and Crohn’s disease
Abnormal NOD-2 expression correlates Abnormal NOD-2 expression correlates with defective epithelial defensewith defective epithelial defense
NOD-2NOD-2 expressed in expressed in Paneth cellsPaneth cells of intestine of intestine
Enteric bacteriaEnteric bacteria induce induce -defensin-defensin through NOD-2 to through NOD-2 to kill luminal microbes.kill luminal microbes.
Clinical evidence:Clinical evidence: CD patients have decreased CD patients have decreased -defensin expression in Paneth cells-defensin expression in Paneth cells
NOD-Like Receptors, RIG and MDANOD-Like Receptors, RIG and MDA
IntracellularIntracellular Microbial Sensors Microbial Sensors
That can detect bacterial and viral ligandsThat can detect bacterial and viral ligands
NODNOD detects PGN of several detects PGN of several bacteriabacteria
Inflammatory responseInflammatory response & & Cell DeathCell Death (IPAF/NAIP)(IPAF/NAIP)
RIG-1/MDA-5RIG-1/MDA-5 detects dsRNA of detects dsRNA of virusvirus
Modulation of Modulation of IFN signallingIFN signalling to control virus to control virus
SummarySummary
Anti-microbial Functions Anti-microbial Functions of Phagocytic Cells of Phagocytic Cells
Upon Receptor-Mediated recognitionUpon Receptor-Mediated recognition
Phagocytosis and InternalizationPhagocytosis and Internalization
Phagosome BiogenesisPhagosome Biogenesis
Anti-Microbial ProductsAnti-Microbial Products
Pro-Inflammatory Response (last lecture)Pro-Inflammatory Response (last lecture)
Major Players Major Players
Polymorphonuclear leukocytes (Polymorphonuclear leukocytes (PMNsPMNs) / neutrophils) / neutrophils
Abundant, short livedAbundant, short lived Elevated number indicate infectionElevated number indicate infection
Professional antigen presenting cellsProfessional antigen presenting cells
Dendritic cells / Langerhan cells (skin) Dendritic cells / Langerhan cells (skin) Monocytes (blood) Monocytes (blood) macrophagesmacrophages (motile or (motile or
stationary), which can be tissue specific stationary), which can be tissue specific Longer lived, lower frequencyLonger lived, lower frequency
Underhill and Ozinsky. Annu. Rev. Immunol. 2002
Formation of the phagolysosomeFormation of the phagolysosomeupon ingestion of a microbeupon ingestion of a microbe
Cellular Microbiology, 1999, 1(3):195-203
Phagosome maturationPhagosome maturation
Degradation in the phagolysosomeDegradation in the phagolysosome
Phagolysosome
Lysosome
Endosome
Bacteria degradation
Acid hydrolases
Phagocytosis and Anti-Microbial ProductsPhagocytosis and Anti-Microbial Products
LysosomesBacteria
Phagolysosome
NAPDHoxidase O2-
H2O2
Proteases
Ionic strength pH
Plasma membrane
Phagosome
Nitric Oxide
AP-1
AP-1
p38
MAPKs
LPS+TLR 4IL-1 + IL-1R1
SAPs/JNKs
TNF- + TNF-R1
GAS
IFN- + JAK1/2
IRF-1
ΚB
NF-ΚB
NF-ΚB
IKB
IFN- + JAK1/2
TNF- + TNF-R1
ISRE
STAT1
STAT2
IRF-9
IFN-/ + JAK/TYKInduction of iNOS
Expression
IL-6 + JAK1/2
NF-IL6
NF-IL6
ArginineCitruline
Heme
FAD
NADPH
gp91phoxp22phox
p47phox
p40phox
O2-O2
P67phox
Rac
RestingActive
PKC
PI3K
PKA
P
P
P P
MAPK
Reactions Between ROS and RNSReactions Between ROS and RNS
NO + ONO + O22-- NONO2 2 + ONOO+ ONOO--
NONOates
S-nitrothiols
Nitrite
Nitrous Acid
Chakravortty and Hensel. Microbes Infect. 2003.
Mechanisms of Microbicidal ActivityMechanisms of Microbicidal Activity
Polyunsaturated LipidsPolyunsaturated Lipids
DNADNA
Enzyme Function Enzyme Function Formation of Oxylipins disrupts membraneFormation of Oxylipins disrupts membrane
Deamination of nucleosidesDeamination of nucleosides
Abasic sitesAbasic sites
Strand breaksStrand breaks
Oxidization and Nitrosylation of SH groupsOxidization and Nitrosylation of SH groups
Nitrosylation of Tyrosine residuesNitrosylation of Tyrosine residues
Inactivation of metal ions at active siteInactivation of metal ions at active site
Depletion of antioxidantsDepletion of antioxidants
Evasion:Evasion:
““the act of physically escaping from something (an the act of physically escaping from something (an opponent or a pursuer or an unpleasant situation) by opponent or a pursuer or an unpleasant situation) by some adroit maneuver”some adroit maneuver”
““the act of physically escaping from something (an the act of physically escaping from something (an opponent or a pursuer or an unpleasant situation) by opponent or a pursuer or an unpleasant situation) by some adroit maneuver”some adroit maneuver”
Nature 3:11, 2002 editorial
•Passive
•Active
Bacterial defense against phagocytesBacterial defense against phagocytes
√ Down-regulate
√ Escape X Endosomal trafficking/
Phagosome maturation
X Defense factors
√ Induction of apoptosis X Uptake
Green: hostOrange: bacterial
EVASION MECHANISMS
MS150502 3
Phagocytosisresistance
Phagocytosissensitive
Wild type S735 Mutant 2A
Streptococcus suis type 2
Adapted from Charland et al.,1998
M. Olivier 0295 2
Protein phosphorylations
PKC
EXTINT
PTKJAK2
FMLP
PIP2
DAG
IP2
•H2O2,O2-
• IL-1•phagocytosis
Ca2+Influx
PLCG
Ca2+stores
Ca2+
IFN
STAT
(SHP-1)
Tyrosinephosphatase
[Ca2+]i
Ser⁄Thr phosphatasePMA
LPG
R
Ca2+
Channel
Cellular functions
Acidphosphatase
JAK1
•MHC Class II•c-fos expression
Host Signalling AlterationHost Signalling Alteration