This document summarizes various inflammatory mediators including cytokines, chemokines, lipid mediators, and neuropeptides. It describes the sources and functions of different cytokines such as IL-1, TNF-α, IFN-γ, and chemokines such as IL-8 and RANTES. It also discusses the roles of lipid mediators like leukotrienes and prostaglandins in inflammation.

1. Inflammatory mediators Dr Chris Corrigan Reader/Consultant GKT School of Medicine

3. Cytokines

10. Cytokine receptor superfamilies Superfamily Receptors for Common structure Cytokine receptor IL-2 (  ), IL-4, Single spanning membrane IL-3/5 (  ), IL-6, glycoporteins with CK, IL-9, IL-12, etc. FNIII and C2 Ig domains Interferon receptor IFN-  , IL-10 SSMG, FNIII domains Immunoglobulin IL-1, IL-6, FGF, Domains containing the M-CSF, SCF “Ig fold” Protein tyrosine EGF, PDGF, M-CSF Intracellular PTK domains kinase receptor SCF, FGF NGF receptor NGF, TNF-I/II 3-4 cysteine-rich repeats in extracellular molecule G-protein coupled C5a, PAF, 7 transmembrane domains 7 transmembrane IL-8 and chemokines with 3 extra- and 4 intra- spanning receptor cellular loops Complement protein IL-2(  ), complement Multiple repeats short domains

15. TNF-  and IL-6 TNF-  IL-6 Source Many Many Structure Pro-peptide; trimerises Single peptide Tumour suppression +++ + Acute phase response +++ ++ Receptor TNFRI/II (CD120a/b) Heterodimer  -chain CD126  -chain CD130 Receptor distribution Widspread Widespread Endothelium T cells, B cells, T cells, APC plasma cells

16. IL-2 and IL-15 IL-2 IL-15 Source Activated T cells Multiple (T cell, (B cells) placenta, muscle, epithelium, monocytes) Actions T cell autocrine/paracrine growth factor B cell differentiation and Ig secretion Monocytes: IL-1 secretion, cytotoxicity, phagocytosis NK cells, LAK cells Receptor  subunits  chains of IL-2R Receptor subunits  other names CD25, Tac, p55 CD122, p75 Kd (nM) 10 1000 none signal transduction no yes yes

17. IL-4 and IL-13 IL-4 IL-13 Source “Th2-type” CD4 T cells “Th1/0/2”-type T cells Some CD8 T cells Some CD8 T cells Thymocytes, eosinophils, mast cells, basophils Actions B cells: class II MHC, CD40, CD23, Ig synthesis IgE class switching (not in the mouse!) Growth and proliferation No effect on T cells of T cells “ Th2-type” T cells Monocytes: complex effects: MHC class II, antigen presentation, cytokine release

22. Th1 Th2 IL-2 IFN-  IL-4 IL-5 TNF-  IL-6 IL-3 IL-10 GM-CSF IL-13 IL-9? Cytolysis Help for IgE synthesis Help for IgG/A/M synthesis Th0 TNF-  Cytokines

23. IFN-  IL-4 IL-13 Th1 Th2 Th0 IL-12 IFN-  IFN-  NK IL-4 IL-13 Mast IL-4 - - M  + - + +

26. Cytokines and Th1/2 T cell development Pro-Th1 cytokines Pro-Th2 cytokines IFN-  IL-4 IL-12 IL-18 IFN- 

28. Interleukin-16 (2) 20 kDa 30 kDa pro-IL-16 caspase 3 121 HIV-1 tetramers CD4 ligand

29. IL-16 and allergic inflammation mast cell IL-5, GM-CSF Rantes, MIP-1  eotaxin IL-16 histamine IL-5 LTB 4 + eosinophil CD4 T cell CD4 CD4

34. Chemokines

36. Chemokine families CXCL 1-15 Two cysteines separated by one amino acid Chromosome 4q12-q21, 10 24-84% homology N-terminal Glu-Leu-Arg (ELR) (neutrophil active) or non-ELR (not neutrophil active) CCL 1-28 Two adjacent cysteines Chromosome 17 25-71% homology CL 1/2 One cysteine Chromosome 1 CX3CL 1

40. Some CXCL chemokines CXCR 3 IP-10 CXCL 10 CXCR 3 MIG CXCL 9 CXCR 1/2 IL-8 CXCL 8 CXCR 2 NAP-2 CXCL 7 CXCR 2 ENA-78 CXCL 5 PF 4 CXCL 4 CXCR 2 GRO  CXCL 1-3

42. Some CCL chemokines CCR 3 Eotaxin 2/3 CCL 24/26 CCR 4 TARC CCL 17 CCR 2/3 MCP-4 CCL 13 CCR 3/5 Eotaxin CCL 11 CCR 1/2/3 MCP-3 CCL 7 CCR 1/3/5 RANTES CCL 5 CCR 1/5 MIP-1  CCL 3/4 CCR 2 MCP-1 CCL 2 CCR 8 I-309 CCL 1

44. Cooperation between eotaxin and IL-5 in eosinophil accumulation eotaxin IL-5 eosinophils & precursors eosinophils Eotaxin mediated but IL-5 dependent Bone marrow Tissues

45. Eotaxin, eosinophils and “Th2-type” T cells Th2 T cell Eosinophil CCR3 CCR3 eotaxin eotaxin IL-5 GM-CSF

47. Lipid mediators (leukotrienes, prostaglandins)

49. 5(S)-HETE Prostaglandins Thromboxanes LTB 4 Nuclear membrane phospholipids 5(S)-HPETE LTA 4 LTC 4 LTD 4 Arachidonic acid LTE 4 Phospholipase A 2 5-lipoxygenase 5-lipoxygenase LTA 4 hydrolase  -glutamyl transpeptidase LTC 4 synthase Dipeptidases Cyclooxygenase

50. Cellular sources of leukotrienes Predominantly LTB 4 Predominantly LTC 4 /D 4 /E 4 Monocytes Monocytes Eosinophils Macrophages Macrophages Mast cells Neutrophils Basophils (B cells) Reflects restricted expression of 5-lipoxygenase LTC 4 synthase and LTA 4 hydrolase are widely expressed

51. Biological activities of leukotrienes LTB 4 LTC 4 /D 4 /E 4 Increase leucocyte adhesion to endothelium Increase microvascular permeability Neutrophil (eosinophil) chemotaxis Vasoconstriction Neutrophil lysosomal release Smooth muscle contraction and superoxide generation Increase mucus secretion Bronchoconstriction (via TXA 2 ) CD8 T cell cytotoxicity IgG production Augment IL-2, IFN-  production

56. Prostanoids Arachidonic acid 15-keto-PGE 2 PGG 2 PGH 2 PGE 2 PGH synthase (cyclooxygenase) 15-keto-PGF 2  PGF 2  6-keto-PGF 1  PGI 2 (prostacyclin) TXB 2 TXA 2 (thromboxane) 9  ,11  PGF 2  PGD 2

57. Biosynthesis and cellular sources PGH synthase 2 (COX) isoforms: COX-1 (ubiquitous, constitutive) COX-2 (inducible in inflammation) Major products characteristic of different cells: Mast cells PGD 2 Platelets TXA 2 Endothelium PGI 2 Smooth muscle PGI 2 Epithelium PGE 2 Macrophages PGF 2  , PGE 2 , TXA 2

58. Prostanoid receptors PGD 2 DP PGE 2 EP-1(smooth muscle contraction)/2(relaxation)/3/4 PGF 2  FP PGI 2 IP TXA 2 TP-1/2 (more?) G-protein linked 7 transmembrane domain proteins Considerable cross-reactivity between receptors

60. Neuropeptides

62. Tachykinins: receptors and metabolism Receptors NK 1 NK 2 NK 3 Affinity SP>NKA=NKB NKA>NKB>>SP NKB>NKA>>SP Distribution Wide Wide Brain & spinal cord Metabolism Angiotensin converting enzyme (ACE): endothelium Neutral endopeptidase (NEP): epithelium

68. Endothelin (ET) and nitrous oxide (NO) ET (vasoconstriction) NO (vasodilatation) Vascular endothelium and endocardium Epithelial cells Peripheral NANC nerves CNS Placenta Inflammatory leucocytes

69. Endothelin (ET) and nitrous oxide (NO): synthesis ET NO pro-ET ET 1-3 L-arginine L-citrulline + NO N G -hydroxy-L-arginine big ET NADPH NADP O 2 H 2 O NADPH NADP O 2 H 2 O

70. NO synthase: isoforms Isoform Expression Distribution nNOS constitutive CNS, peripheral NANC nerves, epithelium eNOS constitutive endothelium, placenta (membrane anchored) iNOS inducible many cells IL-1, TNF-  , IFN-  , LPS stimulatory TGF-  , corticosteroids inhibitory

71. ET and NO: signalling ET 7 transmembrane domain receptor coupled to G-protein Activates PLC and PKC, AP-1, gene expression NO Acts by local diffusion Binds to haem moiety of guanylyl cyclase, elevating cGMP Non-specific cytotoxic/cytostatic effects: forms peroxynitrate which binds to Fe 2+