Page 53 - ebook

Role of endothelial JAM-A in flow dependent vascular inflammation

Jenita Immanuel, Sanguk Yun *

Department of Biotechnology, Inje University, 197 inje – ro , Gimhae – Si, Gyengsangnam – do, Korea

Figure 2. Invitro analysis of the role of endothelial Jam-A in leukocyte recruitment under flow conditions

Endothelial JAM-A contributes to tight junction formation, but when released from lateral

domains, moves to other regions where it mediates leukocyte adhesion and contributes to Si JAM-A
(A) CTRL (B) **

angiogenesis and atherosclerosis. Inflammatory ligands or disturbed flow induces re- ST OS ST OS 5

4
localization of JAM-A from tight junction to the luminal surface to mediate leukocyte IB: P-P65
Endothelial JAM-A contributes to tight junction formation, but when released from lateral domains, moves to other regions where it mediates leukocyte 3

adhesion and contributes to angiogenesis and atherosclerosis. Inflammatory ligands or disturbed flow induces re-localization of JAM-A from tight
binding. Recent phospho-proteomic analysis revealed that JAM-A S285 phosphorylation
junction to the luminal surface to mediate leukocyte binding. Recent phospho-proteomic analysis revealed that JAM-A S285 phosphorylation is P ( P65 )

decreased on fibronectin compared to basement membrane protein. In addition, genetic deletion of JAM-A in bovine aortic endothelial cells plated on IB: T-P65 2
is decreased on fibronectin compared to basement membrane protein. In addition,
fibronectin led to reduced disturbed flow-induced monocyte adhesion. These results suggest that fibronectin may facilitate flow-induced vascular

inflammation by JAM-A S285 dephosphorylation. 1

genetic deletion of JAM-A in bovine aortic endothelial cells plated on fibronectin led to IB: ZO-1

0

ST
OS
reduced disturbed flow-induced monocyte adhesion. These results suggest that IB: B-ACTIN ST OS

CTRL Si JAM-A
fibronectin may facilitate flow-induced vascular inflammation by JAM-A S285

dephosphorylation. CTRL ST CTRL OS

(C)

Keywords : Atherosclerosis, Endothelium, Tight Junction, Fibronectin, JAM-A relocalization

• JAM-A is a transmembrane TJ protein, which maintains endothelial cell-cell interactions under basal

conditions and mediates leukocyte adhesion under inflammatory conditions, and contributes to

angiogenesis and atherosclerosis.
Jam-A KD ST JAM-A KD OS

• Previous studies reported that fibronectin promotes flow-dependent artery remodeling and

atherosclerosis

JAM-A relocalization

Inflammation

JAM-A accumulates at the point of transmigration

(D)

Present in apical surface for LFA-1-mediated 4.5 *

leukocyte binding
4.0

3.5

Leukocyte transmigration 3.0
Monocyte Adhesion 2.5

2.0
Atherosclerosis 1.5

1.0

0.5

0.0

ST OS ST OS

CTRL Si JAM-A

Figure 2 | A. Western blot analysis of NFKB (p65) phosphorylation of control and SiRNA mediated JAM-A KD cells under OSS.

B. Quantification of Western blot results of P(P65) . N=3 (**p=0.0077). C. Thp-1 adhesion assay of control and JAM-A KD BAEC cells under

OSS ( Florescence microscope images ) D. Quantification of adherent monocytes . N=3 (*p=0.0325).

• This study demonstrates that redistribution of JAM-A in endothelial cells plated on fibronectin after stimulation

with oscillatory shear stress results in increased leukocyte recruitment.

• The monocyte adhesion in JAM-A deficient endothelial monolayers was markedly reduced, compared with JAM-A

bearing endothelial cells on fibronectin.

• These results suggest that fibronectin may facilitate flow-induced vascular inflammation by JAM-A S285

dephosphorylation.

The role of endothelial JAM-A in arterial monocyte recruitment

(A) qpcr quantification of Bovine Jam-A
• By the use of RNA interference and genetic deletion, the role of
1.2

JAM-A in flow- dependent vascular inflammation was investigated. • Martin M.N. Schmitt, Endothelial Junctional Adhesion Molecule-A Guides Monocytes Into Flow-Dependent

1
Predilection Sites of Atherosclerosis , Circulation January 7, 2014
1

• To identify FN dependent changes on EC inflammation , JAM-A KD 0.8 • Sanguk Yun et al, Interaction between integrin α5 and PDE4D regulates endothelial inflammatory signaling,

bovine aortic endothelial cells plated on fibronectin were activated quantitative expression (Fold Increase) 0.6 Nat Cell Biol. 2016

by Oscillatory shear stress 12 hrs, which promotes expression of • Sanguk Yun et al, Integrin α5β1 regulates PP2A complex assembly through PDE4D in atherosclerosis,

leukocyte recruitment molecules. 0.4 J Clin Invest. 2019

• Sandra Iden et al, aPKC phosphorylates JAM-A at Ser285 to promote cell contact maturation and tight junction
0.18928
0.2

• For the monocyte adhesion assay, THP-1 cells were added to EC formation, J. Cell Biol. Vol. 196 No. 5, 2012

0
monolayers, incubated for 30 min, washed and bound THP-1 were Ctrl Si Jam-A

counted.