به نام خدا

Molecular markers of innate

immunity and inflammation in

therapeutic intervention by : Mahdi zareiM.Sc. Student ,clinical

biochemistry

Ferdowsi university of mashhad

innate immune system& Inflammation response

The innate immune system utilizes a variety of transmembrane or secreted pattern-recognition receptors (PRRs), which are vital for activation of complement and coagulation cascades,opsonization, phagocytosis, apoptosis and induction of proinflammatory mediators. (Sylvia Adams,2009)

A typical inflammatory response consists of four components: inflammatory inducers, the sensors that detect them, the inflammatory mediators induced by the sensors, and the target tissues that are affected by the inflammatory mediators.( ruslan,2010)

Symptoms of inflammation:

redness and swelling with heat and pain

ruslan,2010

PAMPs , DAMPs(inducers) and PRRs(sensors)

Germline-encoded pattern recognition receptors (PRRs) are

responsible for sensing the presence of PAMPs & DAMPs.

PAMPs : structures conserved among microbial species, which

are called pathogen-associated molecular patterns.

DAMPs : endogenous molecules released from damaged cells,

termed damage-associated molecular patterns.(osamu ,2010)

Classes of PRRs

four different classes of PRR families have been

identified :

Toll-like receptors(TLRs) C-type lectin receptors (CLRs) RIG-I-like receptors (RLRs) NOD-like receptors (NLRs).

Toll like receptor In the late 90’s a protein was discovered in Drosophila named

as Toll. Toll is a transmembrane receptor that is required for the establishment of proper dorso-ventral polarity during embryo formation in Drosophila.(Hashimoto et al., 1988)

Toll is responsible for the production of Drosomycin, antifungal peptide .(Lemaitre et al., 1996).

Toll homologues in mammals as well were revealed known as Toll like receptors (TLRs).

TLRs recognise PAMPs of diverse origin from bacteria, virus, fungi, protozoa and others. TLRs can also sense the molecules that are generated within the host cells alarming a sort of danger signal like heat shock proteins (Hsp60, Hsp70, Hsp90), fibrinogen, surfactant protein A, heparin sulphate and others.

TLR signaling pathway

1) MYD88-dependent pathway:MyD88 dependent

signalling pathway is found to be central to all TLRs except TLR3.

2) TRIF-dependent pathway(MYD88-

independent):TLR3 and TLR4 activate TRIF-dependent

signaling, which activates NF-kB and IRF3 resulting in the induction

of proinflammatory cytokine genes and type I IFNs. (osamu ,2010)

Osamu&shizuo , 2010

Sylvia ,2009

TLRs in cancer and anti-cancer immunotherapy

The TLR3 has been shown to be receptor for viral dsRNA, and also seems to be potentially promising in anti-cancer therapy. Reports have shown that cancer cells themselves express TLR3 in vivo and agonist ploy (I:C) is activating the signalling pathway leading to the anticancer effects (O'Neill et al., 2011)

TLR agonists can induce differentiation, proliferation or activation of Treg cells. Several TLR agonists such as Streptococcal agent OK-432, double stranded RNA and CpG DNA have anti-tumour activity (Chen & Oppenheim, 2009).

Treg cells express TLR4, 5, 7 and 8 in mice. It has been reported that transfer of Treg cells enhanced tumour growth in mice but it was reversed upon stimulation of Treg cells with a TLR8 ligand. Administration of LPS also abrogates Treg activity reveals latent anti-tumour immunity (Chen & Oppenheim, 2009)

Sylvia,2009

TLRs in neurodegeneration

TLR signaling pathways are a potential therapeutic target in AD(Alzheimer’s disease) ; however more work remains to delineate the complex interaction of TLRs in Aβ deposition and clearance and its precise role in AD development. (Okun et al., 2009)

Although TLRs often recognize pathogen associated molecular patterns and protect the body from invasion of microbial pathogens, the expression of TLRs within multiple sclerosis suggests novel roles for these receptors in mediating neurological disease and hence can be used as a biomarker of the neurodegenerative disorders (Okun et al., 2009).

Moreover, it is important to determine the precise role of distinct TLRs in Aβ recognition and clearance, and the activation of glial cells. This may open a window of hope (Arroyo et al, 2011).

nuclear factor kB (NF-kB)

NF-ĸB is a transcription factor that controls the expression of genes involved in inflammation, immunity and apoptosis.

About 100 genes are under the transcriptional control of NF-ĸB.

NF-ĸB is an evolutionary conserved protein having five members in mammals- p50,p52, RelA/p65, RelB and RelC.

All these function either as homodimer or heterodimer for e.g. p50 homodimer and p50/p65 heterodimer.

Canonical and alternative pathways of NF-kB activation

Xavier, 2005

NF-κB and cancer therapy NF-kB regulates the expression of genes involved in many

processes that play a key role in the development and progression of cancer such as proliferation, migration and apoptosis.

constitutive NF-kB activation has been detected in many human malignancies.

some anti-inflammatory drugs may inhibit NF-kB by interfering with IKK activity.

Other substances such as curcumin, trans-resveratrol or parthenolide are natural compounds that have been demonstrated to inhibit IKK activity

Another way to approach NF-kB inhibition is to target the process of proteasome degradation. Proteasome inhibitors prevent NF-kB activation by blocking the degradation of IkBs, NF-kB1/p105 or NF-kB2/p100.(Xavier, 2005)

Drug Molecular targets (NF-kB-linked)

Clinical activity

Aspirin(NSAIDs)Sulfasalazin

IKKβ inhibition colon, lung, prostate cancer, Hodgkin’s disease,

Glucocorticoids IⱪBα transcription Lymphoid leukemias, Hodgkin’s disease, multiple myeloma

Thalidomide/lenalidomideMacrolidesArsenic trioxide

IKKβ inhibition multiple myeloma,chronic lymphocytic leukaemia, various solid tumor

Gene therapy(siRNA)

Decreased p65 expression

not available Sabine,2006

Proinflammatory cytokines

Tumor necrosis factor(TNF)

Interleukin-1

Interleukin-6

Tumor necrosis factor(TNF) as therapeutic target

In patients with meningococcal meningitis serum levels of TNF-α have been shown to correlate with mortality(Arditi,1990) , but other authors have failed to show significant increases in TNF-α in septic patients(Casey,1993).

In a rodent model, mortality after an injection of endotoxin was signifantly decreased by pre-treatment with TNF-a antibodies.(Beutler,1987)

the antibody approach has produced little evidence of benefit in man although improvements in the haemodynamics of patients have been observed.(Exley,1990)

The use of recombinant soluble TNF-a receptors has been shown to improve survival in mice, (Bertini,1993) but at present there have been no similar results in man.

So far the use of TNF-a or its soluble receptors has not proved to be useful as a diagnostic marker.(Giannoudis,2004)

NLRP3 Inflammaso

me Activation

Kate Schroder,2010

Interleukin-1 as terapiotic target Elevated local or systemic IL-1β has been linked to a number of human

hereditary or acquired diseases, and antagonists of IL-1β or its receptor are proving successful treatments for a number of these diseases.(Kate,2010)

Clinical trials are currently assessing efficacy of Anakinra and next-generation IL-1β inhibitors for a wider range of diseases, including cryopyrin-associated periodic syndromes (CAPS), gout, and type II diabetes (T2D). (Hoffman,2009,…)

Gout is an autoinflammatory disease characterized by severe joint inflammation, resulting in arthropathy and considerable pain. Gout is strongly associated with metabolic disturbances leading to elevated blood uric acid levels (hyperuricemia) and the deposition of MSU crystals in joints. (Talbott, 1940)

MSU is a potent activator of the NLRP3 inflammasome in vitro, and MSU-dependent neutrophil recruitment is dependent on the ASC adaptor, caspase-1, and IL-1R in vivo. (Martinon et al., 2006)

A pathogenic role for inflammasome-regulated IL-1β in gout and the closely related disease pseudogout in humans is supported by the success of IL-1β antagonists in clinical trials. (Terkeltaub et al.,2009)

refrences1. Arroyo, S.D., Soria, A.J., Gaviglio, A.E., Rodriguez-Galan, C.M., Iribarren,P. (2011) Toll-like

receptors are key players in neurodegeneration. Inter. Immunopharmacology, Vol.11, pp. 1415–1421.

2. Chen, X. & Oppenheim, J.J. (2009). Regulatory T cells, Th17 cells, and TLRs: Crucial role in Inflammation, Autoimmunity, and Cancer. Pathways, 888.503.3187, Issue 10.

3. Hashimoto, C.; Hudson, K. L. & Anderson, K. V. (1988). The Tollgene of Drosophila, required for dorsal–ventral embryonic polarity, appears to encode a transmembrane protein. Cell, Vol.52, pp. 269–279.

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8. O'Neill, L. A., Sheedy, F. J., & Claire E. McCoy, C. E. (2011). MicroRNAs: the fine-tuners of Toll-like receptor signalling.Nature Rev. Immunol. Vol.11, pp. 163-175.

refrences9. Osamu Takeuchi, Shizuo Akira. (2010). Pattern Recognition Receptors and Inflammation. DOI 10.1016/j.cell. 01.022

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15. Talbott, J.H. (1940). Serum urate in relatives of gouty patients. J. Clin. Invest.19, 645–648.

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Thank you