Cytokines, Cytokine Receptors and Chemokines · •Role of cytokines in inflammation (Chapt. 4 and...
Transcript of Cytokines, Cytokine Receptors and Chemokines · •Role of cytokines in inflammation (Chapt. 4 and...
Chapter 4 Part 1
Sept. 15 & 20, 2016
Sharon S. Evans, Ph.D. Department of Immunology
845-3421 [email protected]
Cytokines, Cytokine Receptors and Chemokines
Membrane-bound IL-6 receptor The Role of IL-6 in Inflammatory Diseases Dr. Bernard Rubin
Macrophage Cytokine Release During Immune Response
Macrophage Cytokine Release During Immune Response
What triggers cytokine release? What is the downstream action of cytokine?
Objectives • Be able to read and understand cytokine
field .
• Have general understanding of current status of cytokine-driven Th cell subset differentiation.
• Understand molecular basis of positive and negative regulation by cytokines.
Outline Cytokines – Part 1 • Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors Cytokines – Part 2 • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Outline
• Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Cytokine – General Characteristics
(Greek) Cyto = cell Kinein = to move
> 200 cytokines
• Contribute to cell-to-cell communication; rarely act alone
• Inducible by discrete stimuli • Produced by many cells; bind to many cells • Low molecular weight (20 – 30 kDa) regulatory
proteins; some direct effector activity • Typically soluble but can be membrane bound • Secreted by lymphocytes, monocytes, other cells
Hormones Growth Factors Cytokines
• Systemic
• Inducible
• Produced by specialized glands
• Act on unique cell type
• Local
• Constitutive
• Produced by multiple cell types
• Act on multiple cells
• Local (although can act systemically)-act short distances; short T1/2 in blood
• Inducible
• Produced by multiple cell types
• Act on multiple cells
Cytokines:
• Interleukins, IL (~35) • Known by common/functional
names (tumor necrosis factor,TNF; interferon, IFN)
• Chemokines (~50); smaller
MW (8-10 kDa)
• Bind high affinity receptors (Kd = 10 -8 – 10 -12M)
• Sensitivity in pM range
• Local reactivity
Hallmarks:
Cytokine release
T lymphocyte Immunological synapse
Dendritic cell
T lymphocyte
High cytokine concentration at site of cell-cell contact
Susceptibility determined by receptor expression
Increase cytokine receptors Increase cytokine production Act on multiple cell types Mobilize network of interacting cells
General Characteristics
• Mediate and regulate the immune system
• Secretion is brief and self-limited • Individual cytokines are produced by
multiple cell types • Act on multiple cell types-pleiotrophic
Pleiotrophy – Different biological effects on different cell targets
General Characteristics
• Mediate and regulate the immune system
• Secretion is brief and self-limited • Individual cytokines are produced by
multiple cell types • Act of multiple cell types-pleiotrophic • Actions are redundant
Redundancy – > 2 cytokines with similar function
General Characteristics • Mediate and regulate the immune
system • Secretion is brief and self-limited • Individual cytokines are produced by
multiple cell types • Act of multiple cell types-pleiotrophic • Actions are redundant • Synergistic and antagonistic actions of
cytokines
Synergy – combined effects of 2 cytokines > the effect of individual cytokines
Antagonism – effect of one cytokine blocked by another
Cytokine cascade – activation of one cytokine produced by one cell type induces cytokine production by other cell types
Outline
• Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Cytokines discovered in 1960s
Antigen stimulation Mitogens
Leukocytes
Supernatant (conditioned medium)
Immune cells
Proliferation Differentiation
Maturation Effector function
Cytokines discovered in 1960s
Antigen stimulation Mitogens
Leukocytes
Supernatant (conditioned medium)
Immune cells
Proliferation Differentiation
Maturation Effector function
Initially analysis difficult: Low amounts (high activity) Difficult to purify Lack assays systems (mainly depend
on bioassays)
Growth Study of IFN Activity Addition of growth factors
(fetal calf serum / nutrients)
IFN-sensitive Daudi B cells
IFN-resistant Daudi B cells
Assay growth
+ IFN
Growth Inhibition of Daudi B cells by IFN-α (Measure Day 3)
Cell
Num
ber
0
50
100
150
200
250
0 1 10 100
IFN- resistant
IFN- sensitive
IFN-α Concentration (U/ml)
Scarozza et al., J Interferon Res, 1992 Appenheimer et al, Am J Health Syst Pharm, 1998
Progress in Cytokine Studies • 1970-1980s – gene cloning
– Produce large amounts of recombinant cytokines
• 1980s – Monoclonal antibody technology – Develop enzyme-linked immunosorbant assays
(ELISA); highly sensitive measurement of cytokine concentration
Principle of ELISA Assay
Adapted from R&D Systems Inc., Minneapolis, Minnesota See also Fig. 20-7 in Kuby 7th edition Chapter 20
Plate pre-coated with antibody
specific for cytokine
Standards or samples added
Enzyme-linked antibody specific for cytokine added
Substrate solution added to generate color
Cytokine (IL-12)
Wash Wash
Intensity of substrate color depends on cytokine concentration
ELISA Assay
Progress in Cytokine Studies • 1970-1980s – gene cloning
– Produce large amounts of recombinant cytokines
• 1980s – Monoclonal antibody technology – Develop enzyme-linked immunosorbant assays
(ELISA); highly sensitive measurement of cytokine concentration
• 1990s – present – other cytokine assays developed – Luminex – Elispot – Intracellular cytokine assays
SA/Biotin Kd~10-14 M
Image from eBioscience See also Fig. 20-9 in Kuby 7th edition Chapter 20
Human IL-17A ELISPOT: Human PBMCs No mitogen
Human PBMCs PMA/Ionomycin
24 hours
Quantify spots
Progress in Cytokine Studies • 1970-1980s – gene cloning
– Produce large amounts of recombinant cytokines
• 1980s – Monoclonal antibody technology – Develop enzyme-linked immunosorbant assays
(ELISA); highly sensitive measurement of cytokine concentration
• 1990s – present – other cytokine assays developed – Luminex – Elispot – Intracellular cytokine assays
Leukocyte
Flow Cytometric Approach to Evaluate Intracellular Cytokine (IL-6)
IL-6
IL-6
IL-6
IL-6
IL-6
Leukocyte
Brefeldin A
IL-6
Blocks protein transport from ER to golgi → cytokines accumulate in ER
IL-6 IL-6
Flow Cytometric Approach to Evaluate Intracellular Cytokine (IL-6)
Leukocyte PE-IL-6 mAb
FITC-CD14 mAb
Fix Permeabilize
Stain
Chen, Immunity 2004
IL-6 IL-6
IL-6
Cell
numbe
r Intracellular IL-6
Control Ab IL-6 Ab
Flow Cytometric Approach to Evaluate Intracellular Cytokine (IL-6)
Outline
• Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Cytokine Groups (6) • IL-1 family
• Hematopoietin family
• Interferon family
• Tumor necrosis family
• IL-17 family
• Chemokine family
α helix β sheets
Derived from x-ray crystallographic analysis
• Amino acid sequences vary
• Similar polypeptide fold, four α-helical regions (A-D) roughly parallel to each other, connected by loops-unique to cytokines
Common Structure Shared by Cytokines
General Functions • Promote proinflammatory responses
– IL-1ß, IL-18, IL-33 – IL-17
• Mediators of natural/innate immunity – Type I IFN – TNF-α – IL-17
General Function
• Regulators of lymphocytic growth, activation and differentiation – IL-2, IL-4, IL-5, IL-12, IL-15
• Activators of inflammatory cells – Type II IFN
• IFN-γ
• Stimulators of hematopoiesis – IL-3, IL-5, IL-7, GM-CSF
Outline
• Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Analysis of Cytokine Receptors
IFN-γRβ / Glial cell nucleus
• Biochemical analysis of receptors hampered by
– low amount of receptors
on cell surface – multiple receptor
subunits
Ab detection of cell surface receptors
IL-2 receptor (CD25)- expressing cell
Fluorescently-labeled anti-CD25 antibody
Control
Activated
Cell N
umbe
r
IL-2Rα (CD25)
Autofluorescence
CD25 Ab
eBioscience CD25 = α chain of IL-2 receptor
IL-6 B
IL-6 B
IL-6 B
IL-6 B
IL-6 B IL-6
B
SA
IL-6 B
SA
SA
SA
IL-6 B
IL-6 B
IL-6 B
SA
IL-6 B
Biotinylated ligand
SA Fluorescently-labeled
streptavidin
Receptor-expressing cell
Fluorokine Analysis of Cytokine Cell Surface Receptor
IL-6
Unlabeled ligand (competitor)
or IL-6R blocking Ab
Cel
l Num
ber
Fluorescence Intensity
IL-6-Biotin
Irrelevant Protein-Biotin
10%
IL-6 Blocking Ab
44%
5%
Appenheimer et al., Eur J Immunol, 2007
Fluorokine Analysis of IL-6 Cell Surface Receptor
Outline
• Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Families of Cytokine Receptors • Six classes of receptors
– IL-1 family of cytokine receptors; part of the immunoglobulin superfamily receptors
– Hematopoietin receptor family (Class I cytokine receptor family); multiple receptor subunits
– Interferon receptor family (Class II cytokine receptor); multiple receptor subunits
– TNF receptor family – IL-17 receptor family – Chemokine receptor family
Receptor Family Ligands IL-1 IL-18 IL-33 M-CSF C-Kit
Immunoglobulin superfamily receptors
IL-1 Family of Cytokine Receptors
Receptor Family Ligands Hematopoietin receptor Family (Class I)
W - tryptophan S - serine P Y-
IL-2 IL-3 IL-4 IL-5 IL-6 IL-7 IL-9 IL-11 IL-12 IL-13 IL-15
IL-21 IL-23 IL-27 GM-CSF G-CSF OSM LIF CNTF GH Prolactin TGF-ß
Subfamilies of hematopoietin receptors have identical signaling subunits
• GM-CSF receptor subfamily (common beta chain)
• IL-6 receptor subfamily (common gp130 subunit)
• IL-2 receptor subfamily (common γ subunit)
Cytokines bind α chain with low affinity; αβ dimer has high affinity for cytokine → transduce signal
Multiple subunits – noncovalent association α chain binds cytokine β chain – signal transducing chain
• IL-6 family cytokines compete for limited # of β chains
• Overlapping biological activities
(CD25)
& Treg cells
5x103 R/cell
CD25 Not normally expressed alone
• β γ chains form pocket • α chain completes pocket, forms lid-accounts for high
affinity binding of trimeric receptor • Signal transduction mediated by β and γ chains but all 3
chains required for high affinity binding of IL-2
Lack WSXWS P Y-
Receptor Family Ligands Interferon receptor Family (Class II)
IFN-α IFN-ß IFN-γ IL-10 IL-19 IL-20 IL-22 IL-24 IL-26 IL-28 IL-29
Receptor Family Ligands TNF receptor superfamily
TNF-α TNF-ß CD27L CD30L CD40L FasL APRIL BAFF Lymphotoxin-ß TRAIL
Receptor Family Ligands IL-17 Receptor Family
IL-17A (CTL-8) IL-17B IL-17C IL-17D IL-17E (IL-25) IL-17F vIL-17 (ORF13)
IL-17 Receptor Family
• Composed of 5 protein chains: IL-17RA, IL-17RB, IL-17RC, IL-17RD and IL-17RE
• Contain SEF/IL-17R (similar expression to fibroblast growth factor/IL-17 receptor) domains
Receptor Family Ligands Chemokine receptors CCL21 (SLC)
IL-8 RANTES MIP-1 PF4 MCAF NAP-2
Summary PART 1 • Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors
PART 2 (Tuesday/September 22, 2015) • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
End Part 1
Chapter 4 Part 2
Sept. 15 & 20, 2016
Sharon S. Evans, Ph.D. Department of Immunology
845-3421 [email protected]
Cytokines, Cytokine Receptors and Chemokines
Membrane-bound IL-6 receptor The Role of IL-6 in Inflammatory Diseases Dr. Bernard Rubin
Macrophage Cytokine Release During Immune Response
Outline PART 1 • Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors
PART 2 (Thursday/September 22, 2015) • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Keys to Cytokine Specificity • Cytokine • Cytokine receptor • Type of pathway activated
– NFκB (e.g., IL-1, IL-17, and TNF) – JAK/STAT (e.g., hematopoietin and interferon) – G protein (e.g., chemokines)
• Sequences activated in promoter of target genes
• Particular cell type – e.g., IL-4 induces different gene expression in T cells vs B cells
Common features of IL-1, IL-17 and TNF family signaling: NFκB pathway
Specificity dictated by: • receptor • signaling mediators • promoter sequence of
target gene • cell type
But the receptors, signaling mediators, and response are different.
Common features of IL-1, IL-17 and TNF family signaling: NFκB pathway
Specificity dictated by: • receptor • signaling mediators • promoter sequence of
target gene • cell type
But the receptors, signaling mediators, and response are different.
Common features of IL-1, IL-17 and TNF family signaling: NFκB pathway
Specificity dictated by: • receptor • signaling mediators • promoter sequence of
target gene • cell type
But the receptors, signaling mediators, and response are different.
Unifying cytokine signaling model – Class I & Class II cytokine receptors
Specificity dictated by: • receptor • signaling mediators • promoter sequence of
target gene • cell type
*STAT, signal transducer and activator of transcription
*
α subunit
JAK2 TYK2 JAK1
IFN-α or IFN-γ
STAT1
STAT1
STAT1 STAT1
STAT1 STAT1
Untx
IFN-α
IFN Activation of JAK/STAT Signaling Pathway
Dunn et al, Cancer Res 65:3447, 2005
STAT1
β subunit
Outline
• Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors • Signal transduction by cytokine receptors (II) • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
TH subsets • TH1 subset
– Viral infection, intracellular pathogen – Bacterial cell infection – Cell-mediated response – IgG2a-Complement fixation, phagocytosis
• TH2 subset – Soluble bacterial products, heminthic (roundworm) infection – Ab/humoral response – IgM→IgE – Allergic responses – IgG1 –does not activate C’
Signal 2 Costimulation (LFA-1/ICAM-1)
Signal 3 Cytokines
IL-12, IFN-γ
Cytokines Program T Cell Activation and Differentiation
IFNγR
IL-12R
Th1
NK NK/T
Th1 cells IL-12
IFNγ
IFN-γ also produced by NK cells, DC IFN-γ stimulates IL-12 secretion and upregulates IL12R on T cells
Cytokine-mediated generation and cross-regulation of TH subsets
α
Eosinophils, T cells, mast cells, basophils, produce IL-4
OX40L +
*Need to know example of cytokines produced by TH subsets
α
Tuberculoid type of leprosy – involves cell- mediated destruction of mycobacteria Lepromatous leprosy – primarily Ab response
Leprosy - chronic infection caused by bacteria Mycobacterium leprae
Figure 11-12 Kuby Immunology, Seventh Edition © 2013 W.H. Freeman and Company
Stat4
IL-12
Cross-regulation at the intracellular level
Similar figure found in Fig 11-10 but lacks IFN-γ
IL-10
IL-10 Acts Indirectly via Control of Monocytes/Macrophage/DC to
Inhibit TH1 Response
• Downregulate MHC class II on APC • Block IL-12 secretion • Inhibit nitric oxide (NO)
production • Inhibit production of inflammatory
cytokines (IL-1, IL-6, IL-8, GM-CSF, G-CSF, TNF-α)
Th2
Th17 and Treg Cells • Th17 (CD4+, FoxP3-)
– IL-17 is a pro-inflammatory cytokine
– Promotes secretion of pro-inflammatory cytokines (IL-6) from fibroblasts, epithelial and endothelial cells.
– Th17 cells are critical to anti-bacterial immunity.
– Overexpression of IL-17 is associated with rheumatoid arthritis, SLE, MS and asthma
• Treg (CD4+, Foxp3+) – Natural (develop in
the thymus) • Prevent effector T
cell development in LN • Produce IL-4, IL-10,
TGFβ
– Induced (develop in the periphery)
• Develop under the influence of TGF-ß
• Inhibit effector T cell function in periphery.
Revised Th Differentiation
Dong, C., Nature Rev. Immunol. 6: 329, 2006
IL-6 TGFβ
STAT3
(STAT3) (Smad3)
Alveolar MΦ = source IL-23 RORγt
Development of Th17 vs Treg Cells
Weaver, C.T. et al, Immunity 24:677, 2006
STAT3/IL-17
IL-23
Smad3
Smad3
Foxp3/IL-10
(RORγt) Th17 IL-17A/F, IL-
21, IL-22
(GATA-3)
Th2 IL-4, IL-5, IL-13
(T-bet)
Th1 IFN-γ
(Bcl6) Tfh
IL-21
CD4
Thp MHC II
α-CD3 α-CD28
IL-12, IFN-γ
IL-4
IL-21, IL-6
APC
(Stat4, STAT1)
(Stat6)
(Stat3)
IL-9 Th9 (PU.1)
Adapted from Mark Kaplan, Indiana U.
TGF-β, IL-2
TGF-β+IL-6, IL-23 (SMAD3, Stat3)
TGF-β+IL-4 (SMAD3, Stat6)
Foxp3 iTreg TGFβ
IL-10
Current model of Th differentiation
(SMAD3, Stat5)
(T-bet)
Th1
Protective Pathogenic Cell-mediated immunity to intracellular pathogens; immunity to protozoa (Leishmania); immunity to fungi (Candida); immunity to bacteria (Mycobacteria)
Autoimmunity – Multiple sclerosis, arthritis, colitis
(GATA-3)
Th2 Humoral immunity; immunity to helminthic parasites (Nippostrongylus, Schistosoma, Trichuris); Immunity to viruses (measles); Immunity to bacteria (Borrelia)
Allergy and atopic responses, cancer
(RORγt) Th17
Immunity to extracellular infectious disease; Immunity to bacteria (Klebsiella), Bacteroides (Citrobacter); Immunity to fungi (candida)
Autoimmunity- Multiple sclerosis, arthritis, colitis, psoriasis
(Bcl6) Tfh
Provide B cell help leading to antibody production GC formation; class switching
Autoimmunity- systemic lupus erythematosus
Immunity to extracellular parasites Immunity to helminthic parasites - Trichuris
Allergy and atopic responses Th9 (PU.1)
Foxp3 iTreg
Immunoregulation, suppress immunity (Th1, Th17)
Cancer
Regulation of Cytokines
• Chromatin Structure – Regulation of expression
Alterations in Chromatin Structure
Ifng
TH1 conditions: Ifng activation 1. Transcription factors direct chromatin
remodeling activity (recruit histone acetyl transferase (HAT), etc)
2. Chromatin remodeling changes the accessibility of cis-regulatory regions (e.g., histone acetylation (Ac) and DNA demethylation generally associated with transcriptional activation at cytokine gene locus).
• T-bet induces hyperacetylation of histones in Ifng locus
• GATA3 induces hyperacetylation of histones in Il4 locus; STAT6 necessary for histone acetylation and DNA demethylation
3. Gene silencing achieved by negative regulatory factors (e.g., GATA-3 antagonizes T-bet activity)
T-bet- histone acetylation STAT4-necessary for histone acetylation
Regulation of Cytokines
• Chromatin Structure – Regulation of expression
• Post-translational processing – Inflammasome (processing of pro-IL-1β)
– Shedding by ectoenzymes (TNF, TNFR)
IL-1β Processing in Inflammasome
Nature Reviews/ Molecular Cell Biology 4, 95, 2003 Nature Reviews/Immunology 7,33, 2007 Nature Clinical Practice/Rheumatology 4,34, 2008
Procaspase-1 Caspase-1
IL-18
IL-18 also processed in inflammasome
NFκB
Regulation of Cytokines
• Chromatin Structure – Regulation of expression
• Post-translational processing – Inflammasome – Shedding by ectoenzymes
• SOCS/CIS Family – Regulation of activity
Activity of Suppressor of Cytokine Signaling (SOCS/CIS)
• SOCS compete with STATs for cytokine receptor binding
• SOCS inhibit JAK activity and target JAKs for proteosome-mediated degradation
Role of SOCS in Th1/2 Development
Outline
• Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors • Signal transduction by cytokine receptors (II) • T cell differentiation • Cytokines and disease pathogenesis • Role of cytokines in inflammation (Chapt. 4 and 14)
Cytokine-Related Diseases • Septic shock – systemic
bacterial infections, trauma, injury, ischemia
• Cytokine activity implicated in lymphoid, myeloid, and epithelial cancers
• Cytokines drive autoimmunity
Septic shock (TNF, IL-1β)
Cytokines Drive Epithelial Cancers (Colon, Liver cancer)
Michael Karin & Florian R. Greten Nature Reviews/ Immunology 5, 749-759, 2005
Cytokine Therapies
Target CD25 (IL-2Rα) - Kidney, heart transplant (Host vs graft) – also proposed to target Treg in cancer
Cytokine Targets in Rheumatoid Arthritis
The Scientist Tocilizumab
IL-6 Targeting in Rheumatoid Arthritis
Inflammation
Humanized Ab to IL-6R
Concept of blocking IL-6 signaling by Tocilizumab
STAT3 JAK1/2
Summary Cytokines - PART 1 • Biological activity of cytokines • Methods to analyze cytokines • Structure of cytokines • Detection/structure of cytokine receptors Cytokines - PART 2 • Signal transduction by cytokine receptors • T cell differentiation • Cytokines and disease pathogenesis CHAPTER 4 and 14 (Sept. 24 & 29, 2015) • Role of cytokines/chemokines in lymphocyte
trafficking and inflammation