IMMUNOMETABOLISM - Tomáš Doležal

transcript

Cell regulation and signaling – 12.11.2015 České Budějovice

Pathogen-associated molecular pattern

Bacteria

nucleus

cytoplasm

Pattern recognitionreceptor

TLRsin mammals

Drosophila PGRPPeptidoglycan-recognition protein

Pattern recognition receptors of immune system recognize pathogen-associated molecular patterns

Mammalian TLRs are direct pattern-recognition receptors involved in the recognition of infectious agents

Drosophila Toll does not directly recognize microbial patterns!

INFLAMMATION

clonal expansion

Pathogen-associated molecular pattern

Bacteria

nucleus

cytoplasm

Pattern recognitionreceptor

Immune cell activation - differentiation - proliferation and differentiationTurning ON immune effector genesRelease of cytokines

Inflammatory response

RECOGNITION

PATHOGEN ELIMINATION

IMMUNOLOGY

METABOLIC SWITCHessentialimmunomodulatory

IMMUNOMETABOLISM

What is going on inside the cell?

How does it affect systemic metabolism?

Vander Heiden Science 2009

Warburg effect – increased glycolysis even under aerobic conditions

Metabolic switch in carbon source for lipid synthesis

Bioessays 35: 965–973

Hypoxia inducible factor HIF – master regulator of Warburg effect

Warburg used by immune cells

Tripmacher Eur. J. Immunol. 2008

CD4+ T cells: in glucose-containing medium, both cytokine production and proliferation were unaffected, even under complete OXPHOS suppression.

Verbist Seminars in Immunology 2012

Krawczyk BLOOD 2010

Dendritic cell

No proliferation, important for survival while travelling to lymph node and presenting to T cells.β-oxidation/OXPHOS

in resting DC

Front. Immunol., 30 January 2014 | http://dx.doi.org/10.3389/fimmu.2014.00024

Pathogen recognition receptor (e.g. TLR) activation stimulates PI3K/Akt and HIF

Warburg effect

Two types of macrophages – pro-inflammatory M1 (Warburg) and healing M2

IMMUNOMETABOLISM

What is going on inside the cell?

How does it affect systemic metabolism?

Energy expenditure of systems and organs under various conditionsSystem/organ Energy expenditure per day (kJ/day)

Total body basal metabolic rate 7,000

Total body metabolic rate with usual activity 10,000Total body metabolic rate during minor surgery 11,000

Total body metabolic rate with multiple bone fractures Up to 13,000

Total body metabolic rate with sepsis 15,000Total body metabolic rate with extensive burns 20,000

Total body daily uptake (absorptive capacity in the gut) 20,000

Immune system metabolic rate under normal conditions 1,600

Immune system metabolic rate moderately activated 2,100Central nervous system metabolic rate 2,000

Muscle metabolic rate at rest 2,500Muscle metabolic rate activated 2,500 to 10,000 and more

Spies Arthritis research & therapy 2012

Activated immune response is energetically costly

glucose

nutrientsfor pathogen

loss of energy reserves (wasting)

ENERGYRELEASE

Negative feedbackREGULATION

Insulin signaling Insulin

PI3K/Akt

growth

glucose

trans-location

glycolysis

glucose

growth

Insulin resistance

growth

Inflammation – pro-inflammatory cytokines released by immune cells

activation of immune response

TNF-αIL-6

IFN-γ

TNF-α

Insulin signaling Insulin

PI3K/Akt

growth

glucose

trans-location

glycolysis

glucose

growth

Insulin resistance

growth

TNF-αYTNFR

glucose

e.g. muscle cell

glucose

Front. Endocrinol., 10 May 2013 | http://dx.doi.org/10.3389/fendo.2013.00052

Cross-talk between insulin and inflammatory signaling pathways

WARBURG

Selfish signal(TNF-α, IFN-γ, IL-6)

Insulin resistance

Systemic metabolic switchSelfish immune systemacute chronic

Insulin resistance is a way of immune cells to usurp energy/nutrients from the rest of the organism

Selfish immune systemimmune system (and brain) hierarchically above the rest of the organism in allocating energy/nutrition (they do not become insulin resistant)

Effective immune response requires energy

During acute stress, it is good to be selfish

Straub Arthritis Research & Therapy 2014

Insulin resistance is a way of immune cells to usurp energy/nutrients from the rest of the organism

Selfish immune systemimmune system (and brain) hierarchically above the rest of the organism in allocating energy/nutrition (they do not become insulin resistant)

Chronic activation is a pathological state

Chronic insulin resistance –> various diseases

Straub Arthritis Research & Therapy 2014

Systemic metabolic regulations during immune response in Drosophila

Parasitoid waspLeptopilina boulardi

…infecting larva of Drosophila melanogaster

MODEL:

Hml>GFP

MSN>GFP

Lamellocytedifferentiation

encapsulation and melanization

within 24 hours

within 48 hours

our white!

L2/L3 (~72 h) = 0 hpi

24 hpi

14C MACROMOLECULE DISTRIBUTION 14C TISSUE DISTRIBUTION

SYSTEMIC METABOLIC SWITCH

IMMUNE CELLS

D[U-14C]-glucose in diet

Immune cells increaseglycolysis (Warburg)

(Strasser and Dolezal, unpublished)

SYSTEMIC METABOLIC SWITCH

Infection slows down development

parasitoid egg

GLUCOSE

↑ aerobicglycolysis

pro-hemocyte

lamellocyte

proliferation

differentiation

encapsulationegg recognition

developing larval tissue

activation

systemic metabolic switch

nucleoside transporter

adgf-a mutant

wild type

Extracellular adenosine • suppression of energy-consuming

processes• suppression of energy storage• energy release … hyperglycemia

(Dolezal, PLoS Biology 2005)

nucleoside transporter

Extracellular adenosine • suppression of energy-consuming

processes• suppression of energy storage• energy release … hyperglycemia

adoR mutant

Blocking adenosine signaling by adoR mutation suppresses metabolic switch

Lack of adenosine signaling-mediated systemic metabolic switch has consequences…

adoR mutant = low number of lamellocytes

(no problem with pathogen recognition, activation and lamellocyte differentiation, it is just less effective)

Adenosine signaling required for effective immune response

Trade-off between development and immunity

parasitoid egg

GLUCOSE

↑ aerobicglycolysis

pro-hemocyte

lamellocyte

proliferation

differentiation

activation

TRADE-OFF

Adenosine mediates systemic metabolic switch … where does it come from?

Srp expressed in all hematopoietic cellsand fat body

Equilibrative nucleoside transporters … ENT1, ENT2 and ENT3

Knockdown in various tissues by Gal4>UAS-RNAi:

No effect in fat body or circulating hemocytes

Knocking down ENT2 in prohemocytessuppresses immune response

Blocking adenosine transport from immune cells lowers number of lamellocytes

parasitoid egg

e-Ado ↑ aerobicglycolysis

pro-hemocyte

lamellocyte

proliferation

differentiation

SELFISH IMMUNE SYSTEM

activation

GLUCOSE

↓ ATP

↑ AMP

5’NT

AMPK anabolicprocesses

↓ ATP

↑ AMP

5’NT

OXPHOS

anabolicprocesses

GLUCOSE

↑ ATP

AdoRHow?

Selfish signal

Immune cellselfish

Developing cellunselfish

Why Ado?

Adjusting systemic metabolism according to actual energy state of immune cells?

Pro-inflammatory cytokines (TNF-α, IFN-γ, IL-6) act as selfish signals too … … measuring the extent of immune activation?

INFLAMMATION

damage ATP

↑Ado

local higher increase

systemic lower increase

↑Ado

ectoenzymes↓ATP↑AMP

FATIGUEdecreased overall

activity and metabolism

Glucose

Immunecell

WARBURG

Immune activation

5’NT

? Blood vessel

Adenosine – a selfish immunity signal even in mammalian system?

Dolezal – Oncotarget 2015

IMMUNOMETABOLISM - Tomáš Doležal

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