MR. WISITSAK PHOKSAWAT

Ph.D. candidated in Biomedical Sciences Program,

Graduate School, Khon Kaen University, Thailand.

Evidence of NKG2D/ ligands interaction promote Atherosclerosis

Advisor : Assoc. Prof. Dr. Chanvit Leelayuwat

Multi-risk factor of Atherosclerosis

Dyslipidemias

- high of low-density lipoprotein cholesterol (LDL-C)

- low of high-density lipoprotein (HDL)

Diabetes Mellitus and Impaired glucose tolerance (IGT)

Hypertension

Obesity and overweight

Cigarette smoking

Increased age, Gender, Family history and race

Involvement of abnormal metabolic conditions in atherosclerosis

abnormal metabolic conditions( Dyslipidemias)

Stress to artherial endothelial cells(up-regulated chemokine and adhesion molecules, recruit atherogenic

immune cells)

Vascular inflammation

Atherosclerosis(chronic inflamation and auto-immune

disease)

Initiation of atherosclerosis

Picture from Obesity, inflamation, and altherosclerosis. Nat Rav. Cardiol. (2009)

LDL oxidation

Nonenzymatic mechanisms

- the catalysis by transition metal ions, copper(Cu2+), iron(Fe2+),

and hemin (Fe3+)

- hemoglobin (Hb)

Enzymatic mechanisms

- myeloperoxidase

- 15 or 12/15-lipoxygenase (LO)

- NADPH oxidases

Classification of scarvenger receptors base on structural motifs(Krieger and colleagues, 1997)

• SR-AI/SR-AII, CD36, SRB1, MARCO, LOX1, SREC-1/SREC-II, SR-PSOX, Stabilin-1

recognize modified low-density lipoproteins.

Picture from Role of macrophage scavenger receptors in atherosclerosis, immunobiology (2012).

Schematic mechanisms of scavenger receptor mediated interaction with modified lipoproteins

I. Recognition of the ligand

II. Invagination of the membrane

forming vesicles

III. The degradation of modified

lipoprotein ligands in

lysosomes

Three steps are ;

Picture from Role of macrophage scavenger receptors in atherosclerosis, immunobiology (2012).

Picture from Obesity, inflamation, and altherosclerosis. Nat Rav. Cardiol. (2009)

T cells in altherosclerosis

• Macrophage can take up, process, and present neo-antigens such as oxLDL to CD4+ T cells.

• About 10 % of CD4+ T cells cloned from human lesion recognize oxLDL on MHC classII (DR).

Cytokines involvement in atherosclerosis

Pro-athergenic cytokines Anti-athergenic cytokines

TNF-αIL-1IL-1 βIL-2IL-12IL-18IFN-α

IFN-ɣ

TGF-βMCP-1RANTESCD40LIL-4 ?IL-6 ?

TGF-βIL-5IL-9IL-10IL-13IL-33

IL-1raIL-4 ?IL-6 ?

• Induce Pro-athergenic chemokine release• Activated adhesion molecules expression• Effects SMC migration and proliferation• Regulated immune responses promoting Th1 response• Stimulates MMP expression• Induces apoptosis• Modulates extracellular matrix expression

• Induce anti-athergenic chemokine release• Regulated immune responses promoting Th2 response• Stimulates profibrotic state promoting wound healing and angiogenesis

NKG2D receptor

• KLRK1 (killer cell lectin-like receptor subfamily K, member 1)

• encode on human chromosome 12 within NK gene complex and

chromosome 6 in mice

• Type II C-type lectin-like family of transmembrane proteins

• express as homodimer on NK cell, NKT cell, + T cell and some

CD8+ T cells

• function both an activating and co-stimulatory receptor

• bind to variety of ligands;

- Human : ULBP, RAET1, MICA,MICB

- Mouse : RAE1, H60, MULT1

Inhibitory and activating receptors of NK cells

• inhibitory receptors KIRs CD94/NKG2A ILTs • activating receptors CD16 NCRs KIR2DS CD94/NKG2C NKG2D

Upregulation of NKG2D Ligands in Sera and Atherosclerotic Plaques of patients with

Metabolic Dysfunction.

NKG2D ligands were up-regulated in atherosclerotic plaques

Both macrophage and endothelial cells of atherosclerotic plaques expressed MICA/B

* p<0.05 , ** p< 0.01 , *** p< 0.001

Preferential Upregulation of NKG2D Ligands in Tissue and Organs of

ApoE -/- Mice Where Abnormal Metabolites Accumulate

The ligands are up-regulated (10-30 fold)

in the atherosclerotic aortas.

NKG2D plays a critical role in plaque formation in Western diet (WD)–fed and streptozotocin(STZ) -diabetic apolipoprotein E–deficient (ApoE ¯/¯) mice.

Preventing NKG2D/Ligand Interactions Suppresses Plaque Formation in ApoE -/-Mice

(reduced 5-6 fold)

* p<0.05 , ** p< 0.01 , *** p< 0.001

Oil red O staining of cross sections of aortic roots also revealed significantly reduced plaque formation in Klrk1-/-ApoE-/- mice compared with the ApoE-/- controls

* p<0.05 , ** p< 0.01 , *** p< 0.001

Preventing NKG2D/Ligand Interactions Reduces the Systemic Production of Multiple Cytokine Markers Associated With Immune Activation

The NKG2D/ligand-mediated immune cell activation associated with atherosclerotic

progression might function at least partly through the increased production of these cytokines.

* p<0.05 , ** p< 0.01 , *** p< 0.001

Acknowledgement

Associate Professor. Dr. Chanvit Leelayuwat for my advisor.

Associate Professor. Dr. Nantarat Komanasin and Dr. Amornrat Jumniansong

Cardiovascular Research Group (CVRG), Khon Kaen University, Thailand.

The Higher Education Research Promotion and National Research

University Project of Thailand, Office of the Higher Education Commission, through

the Center of Exellence in Specific Health Problems in Greater Mekong Sub-region

Cluster (SHeP-GMS), Khon Kaen University (KKU).

All members of LAB3 and CVRG groups

Thank you for your attention