Manifestation of Novel Social Challenges of the European Union in the Teaching Material of Medical Biotechnology Master’s Programmes at the University of Pécs and at the University of Debrecen Identification number: TÁMOP /1/A

SIGNALING IN THE INNATE IMMUNE SYSTEM PRR SIGNALING Tímea Berki and Ferenc Boldizsár Signal transduction Manifestation of Novel Social Challenges of the European Union in the Teaching Material of Medical Biotechnology Master’s Programmes at the University of Pécs and at the University of Debrecen Identification number: TÁMOP /1/A

TÁMOP /1/A PAMPs The microbe-specific molecules that are recognized by a given Pattern Recognition Receptor (PRR) are called Pathogen-Associated Molecular Patterns (PAMPs): Bacterial carbohydrates (e.g. lipopolysaccharide or LPS mannose) Nucleic acids (e.g. bacterial or viral DNA or RNA), Bacterial peptides (flagellin, ax21) Peptidoglycans Lipotechoic acids (from Gram positive bacteria) N-formylmethionine, lipoproteins and fungal glucans Endogenous stress signals are called DAMPs (danger-associated molecular patterns) and include uric acid

TÁMOP /1/A Endocytic Pattern- Recognition Receptors Mannose receptors of phagocytes are C-type lectins bind mannose-rich glycans with mannose or fructose as the terminal sugar that are commonly found in microbial glycoproteins and glycolipids. Scavenger receptors bind to bacterial cell wall components such as LPS, peptidoglyan and teichoic acids and stressed, infected, or injured cells. Scavenger receptors include CD36, CD68, and SRB-1. Opsonin receptors bind microbes to phagocytes. N-formyl Met receptors bind N-formyl methionine, the first amino acid produced in bacterial proteins.

TÁMOP /1/A Signaling Pattern- Recognition Receptors Cell surface /Extracellular TLRs: TLR1, TLR2, TLR4, TLR5, and TLR6 Signaling PRRs found in the membranes of the endosomes /phagolysosomes: TLR3, TLR7, TLR8, and TLR9 Signaling PRRs found in the cytoplasm: NOD1, and 2 (CARD-containing proteins)

TÁMOP /1/A Signaling PRRs found in the membranes of the endosomes/phagolysosomes TLR-3, 7 and 8 bind single- or double- stranded viral RNA TLR-9 binds unmethylated cytosine-guanine dinucleotide sequences (CpG DNA) Most of the TLRs that bind to viral components trigger the synthesis of interferons that block viral replication within infected host cells

TÁMOP /1/A Toll-like receptors (TLRs) They are single, membrane-spanning, non- catalytic receptors that recognize structurally conserved molecules derived from microbes They receive their name from their similarity to the protein coded by the Toll gene identified in Drosophila in 1985 by Christiane Nüsslein-Volhard. The gene in question, when mutated, makes the Drosophila flies look unusual, or 'weird'. The researchers were so surprised that they spontaneously shouted out in German "Das ist ja toll!" which translates as "That´s wild!"

TÁMOP /1/A Toll-like receptors-pattern recognition Peptidoglycan (G+) Lipoprotein Lipoarabinomannan (Mycobacteria) LPS (Leptospira) LPS (Porphyromonas) GPI (Trypanosoma cruzi) Yymosan (Yeast) dsRNAFlagellin Unmethylated CpG DNA TLR2TLR1TLR5TLR3TLR9TLR6TLR2 Lipoteichoic acids (G+) RVS F protein LPS (G-) TLR4CD14 MD-2

TÁMOP /1/A The horseshoe structure of TLR3 TLR3 structure showing attached sugars (spheres) and internal structures (wires, arrows, and helixes) GNU Free Documentation License

TÁMOP /1/A MyD88 TRIF TLR3TLR7TLR2 PKA TAK1 PKR MKKs lBlB lBlB p50 p65 MyD88 LPS TLR4 MD2 LBP dsRNA TBK1 IKK  MDA-5 RIG-1 IPS1 TLR9 JAK2 mTOR PI3K CD14 TLR types

TÁMOP /1/A TLR signaling adaptor molecules: Induces potent innate immune responses that signal through adaptor molecules: Myeloid differentiation factor 88 (MyD88) Toll/interleukin (IL)-1 receptor (TIR) domain containing adaptor protein (TIRAP) TIR domain containing adaptor inducing interferon (IFN) (TRIF) TRIF-related adaptor molecule (TRAM) to activate

TÁMOP /1/A TLR signaling TAB2 TLR4 MD2 LBP TRAF6 TRIF TBK1 IRAK1 IRAK4 RIP PI3K Akt ERK1/2 MEK1/2 p38 MKK3/6 MAP3Ks JNK MKK4/7 AP-1 TAK1 TRAP TRAM IRF3 IKKs IkB NFkB MyD88 IKKe CD14 Nucleus Cytoplasm Plasma membrane

TÁMOP /1/A TLR related transcription factors Nuclear factor (NF  B) Activator protein 1 (AP-1) Interferon regulatory factors (IRFs) antibacterial and antiviral responses to induce antibacterial and antiviral responses

TÁMOP /1/A Toll-like receptor inhibitors MyD88 TRIF TLR3TLR7 TLR2 PKA SP SB U0126 PD98059 H-89 Celastrol Bay Aminopurine PepinhTRIFPepinhMYD TAK1 PKR p38 JNK MKKs lkB p50 p65 MyD88 Polymixin B CLI095 LPS TLR4 MyD88 MD2 LBP dsRNA BX795 MDA-5 RIG-1 IPS1 TLR9 Chloroquine JAK2 Wortmannin Rapamycin LY AG490 mTOR PI3K CD14 OxPAPC

TÁMOP /1/A Inflammatory cytokines Interleukin-1 (IL-1) Tumor necrosis factor-alpha (TNF-alpha) Interleukin-12 (IL-12) Chemokines such as interleukin-8 (IL-8), MCP-1, and RANTES

TÁMOP /1/A Opsonins Acute phase proteins like mannose-binding lectin (MBL), C-reactive protein (CRP) C3b C4b complement factors Surfactant proteins in the alveoli SP-A and SP-D The antibody molecule IgG can function as an opsonin

TÁMOP /1/A Secreted PRRs Complement receptors Collectins Pentraxin proteins such as serum amyloid and C- reactive protein Lipid transferases Peptidoglycan recognition proteins (PGRs) LRR, XA21D One very important collectin is mannan-binding lectin (MBL), a major PRR of the innate immune system that binds to a wide range of bacteria, viruses, fungi and protozoa. MBL predominantly recognizes certain sugar groups on the surface of microorganisms but also binds phospholipids, nucleic acids and non-glycosylated proteins.

TÁMOP /1/A Complement receptors CR1 CR2 CR3 CR4 CR2 CR3 CR4 CRIg SIGNR1 C3aR C5aR C1qR CD46 CD55 CD59 C3aR C5aR C1qRP Antigen recognition and uptake Pathogen recognition and/or clearance Modulation of T H 1/T H 2 commitment Antigen recognition and uptake Cytokine modulation and APC maturation CR1 Inhibits cell proliferation Expressed on <15% Unknown Expressed on <5% Cytokine modulation Expressed on activation T-cell trafficking Upregulated by activation Cytokine modulation CD46 CD55 CD59 Activation/proliferation, cytokine modulation and lineage commitmentAPC T cell

TÁMOP /1/A Overview of complement receptor (CR) and Toll-like receptor signalingTLRCR3C5aR C3b gC1qR C1q CD46 iC3b C5 BacteriaViruses Erk1/2 PI3K TLR4-induced IL-12 inhibited by posttranscriptional mechanism TLR4-induced IL-12 inhibited by posttranscriptional mechanism Nucleus IL-12p35 IL-12/IL-23p40 IL-23p19 IL-27p28 IRF-1, IRF-8 IRF-1, IRF-8 C5a