Inflammatory Pathways in Sepsis: TLRs and Innate …...Inflammatory Pathways in Sepsis: TLRs and Innate Immunity Keith R. Walley, MD St. Paul’s Hospital University of British Columbia

Inflammatory Pathways in Sepsis:

TLRs and Innate Immunity

Keith R. Walley, MD

St. Paul’s Hospital

University of British Columbia

Vancouver, Canada

Early

Goal-Directed

Therapy

Rivers E et al. NEJM

345:1368-77, 2001

Early Resuscitation Limits the

Innate Immune Response

• Why does early resuscitation work in any

form of shock?

• Why does delayed resuscitation (any

shock) result in distributive shock?

• Why does sterile severe pancreatitis look

like septic shock?

• INJURY AND INFECTION SHARE THE

SAME EARLY INFLAMMATORY

PATHWAYS – TLRs and Innate Immunity

PAMPs Pathogen-Associated

Molecular Patterns

Wang et al. Microbes

Infect (2009)

Toll-Like

Receptors

(TLRs)

on WBCs

DNA

DNA viruses

RNA

RNA viruses

PGN

Gram+, yeast

LPS

Gram-

DNA

(hepatocytes,

cardiomyocytes)

RNA

(trophoblast)

HSP60,

HSP70

HSPs,

S100A8 / A9

HMGB1

Endogenous

TLR Ligands

on many cells

DAMPs Damage-Associated

Molecular Patterns

Wang et al. Microbes

Infect (2009)

Cardiomyocytes

express Toll-like

receptors

Boyd et al. Cardiovascular

Research. 72: 384-393, 2006

TLR ligands decrease contractility

TLR2 TLR4 TLR5

Boyd et al. Cardiovascular Research. 72: 384-393, 2006

DAMPs that increase NF-B

in heart cells

Mathur S, Walley KR, Wang Y, Indrambarya T, Boyd JH. Circ J. 75:2445-52, 2011

NF

-B

Activity

HSP70 increases inflammation and

decreases contractility

Mathur S, Walley KR, Wang Y, Indrambarya T, Boyd JH. Circ J. 75:2445-52, 2011

HSP70 decreases contractility

via TLR2

Mathur S, Walley KR, Wang Y, Indrambarya T, Boyd JH. Circ J. 75:2445-52, 2011

HSP70 10g/mL HSP70 10g/mL

S100A8 and S100A9 are expressed

during myocardial inflammation

Boyd et al. Circ Res. 102:1239-1246, 2008

Induced by TLRs

S100A8 and S100A9 contractility C

ontr

actilit

y

Boyd et al. Circ Res. 102:1239-1246, 2008

Any evidence that TLRs make a

difference in human sepsis?

Innate immune genetic variants alter

susceptibility to the corresponding infection

Sutherland AM, Walley KR, Russell JA. Critical Care Medicine. 33(3):638-44, 2005

Gram + Gram -

Mannose Binding Lectin (MBL)

binds all pathogen carbohydrate

Gram + and Gram - Gram-

LPS / CD14

TLR1 genetic variant alters

culture positivity and survival

Wurfel MM et al. Am J Respir Crit Care Med. 178:710-20, 2008

Gram+

IRAK-4 genetic

variant alters culture

positivity

Sutherland AM et al. J Innate Immun, 3(5):447-58, 2011.

Is there anything we can do?

• Early treatment of infection (PAMPs)

– reduce pathogen load

– clear endotoxins faster

• Why does early resuscitation work in any

form of shock?

– reduce DAMP release (e.g. HSP70)

Co-investigator

John Boyd

Funding

Heart & Stroke Foundation

CIHR

Michael Smith Foundation

People

Yingjin Wang

Ryon Bateman

Chiho Tokunaga

Edmond Chau

Ehsan Davani

Haley Roberts

Thoma Kareco

Sumeet Mathur

Sorel Bosan

EXTRA SLIDES

S100A8 / S100A9 Bind TLR4

Ehrchen JM et al. J. Leukoc. Biol. 86: 557–566; 2009

DNA

(hepatocytes,

cardiomyocytes)

RNA

(trophoblast)

HSP60,

HSP70

HSPs,

S100A8 / A9

Endogenous

TLR Ligands

on many cells

DAMPs Damage-Associated

Molecular Patterns

Wang et al. Microbes

Infect (2009)

CpG binds TLR9 and induces

counter-regulatory A20 (TNFAIP3)

Mathur S, Walley KR, Boyd JH. Shock. 36(5):478-483, 2011.

Murine Myocardial

Ischemia-Reperfusion

Early Resuscitation Limits the

Innate Immune Response

• Why does early resuscitation work in any

form of shock?

• Why does delayed resuscitation (any

shock) result in distributive shock?

• Why does sterile severe pancreatitis look

like septic shock?

• INJURY AND INFECTION SHARE THE

SAME EARLY INFLAMMATORY

PATHWAYS – TLRs and Innate Immunity

ICAM-1 expression on activated

cardiomyocytes

A B

*

ICAM-1 binding signals through the

cytoskeleton (FAK)

Control ICAM-1 Cross-linked

Davani et al. Am J Physiol Heart Circ Physiol. 287(3):H1013-22, 2004.

Decreased contractility is due to

heterogeneous Ca2+ release

Davani et al. Am J Physiol Heart Circ Physiol. 287(3):H1013-22, 2004.

What binds ICAM-1?

Fibrinogen (brown) extravasates into

myocardium during inflammation

Control Endotoxin

Decreased Contractility:

Fibrinogen binding ICAM-1

Untreated Albumin Fibrinogen Denatured

Fibrinogen

S100A8 and S100A9 contractility by

binding RAGE (maybe SERCA2)

Boyd et al. Circ Res. 102:1239-1246, 2008

RAGE: Receptor for Advanced Glycation End products

- Also binds TLR4

TLR ligands signal via NF-B to induce

cytokine production by cardiomyocytes

Boyd et al. Cardiovascular Research. 72: 384-393, 2006.

Con 2 4 5

TLR Ligand

TLR-mediated ICAM-1 expression is

NFB-dependent (PDTC inhibits)

TLR2 TLR4 TLR5

Boyd et al. Cardiovascular Research. 72: 384-393, 2006.

NIK