Assessment of the integrin alpha5beta1 antagonist JSM6427 in proliferative vitreoretinopathy using in vitro assays and a rabbit model of retinal detachment.
OBJECTIVE
To explore the role of integrin alpha5beta1 in proliferative vitreoretinopathy (PVR) pathogenesis by evaluating the expression alpha5beta1 on ARPE-19 cells and patient proliferative membranes, quantifying the inhibitory effects of JSM6427 (a small molecule alpha5beta1 inhibitor) on ARPE-19 cell adhesion and migration, and assessing the therapeutic potential of JSM6427 in a rabbit retinal detachment model.


METHODS
Expression of alpha5beta1 was evaluated on activated ARPE-19 cells by flow cytometry and on PVR membranes by immunohistochemistry. ARPE-19 cells were used in fibronectin-dependent adhesion and migration assays with various concentrations of JSM6427; IC(50) was calculated. In the rabbit model, eyes were intravitreally injected with vehicle or JSM6427 on day 0 or 1 after retinal detachment; BrdU was administered intravitreally on day 3, and retinal tissues were harvested on day 3 (4 hours later) or 7. Retinal scarring, cellular proliferation, and inflammatory responses were quantified, and retinal morphology was analyzed in retinal sections.


RESULTS
Activated ARPE-19 cells and PVR membranes expressed high levels of alpha5beta1; expression was low in control eyes. JSM6427 provided a dose-dependent blockade of ARPE-19 cell adhesion to fibronectin (IC(50), 7.1 +/- 2.5 microM) and inhibition of migration (IC(50), 6.0 +/- 4.5 microM). In the rabbit model, intravitreal injection of JSM6427 provided significant inhibition of proliferation of retinal cells (Müller cells, microglia, and macrophages) on days 3 and 7 after detachment and inhibition of inflammatory response and retinal scarring on day 7 after detachment.


CONCLUSIONS
JSM6427 is a promising treatment for PVR, with data suggesting that inhibition of alpha5beta1-fibronectin interactions addresses multiple pathways involving retinal pigment epithelial, glial, and inflammatory cells.
Zahn
Grit
G
Jerini AG, Berlin, Germany. grit.zahn@gmx.net
Volk
Kristine
K
Lewis
Geoffrey P
GP
Vossmeyer
Dörte
D
Stragies
Roland
R
Heier
Jeffrey S
JS
Daniel
Paul E
PE
Adamis
Anthony P
AP
Chapin
Ethan A
EA
Fisher
Steven K
SK
Holz
Frank G
FG
Löffler
Karin U
KU
Knolle
Jochen
J
D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D019773:Epiretinal Membrane / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D039081:Integrin alpha5beta1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008297:Male; D011422:Propionates / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D011759:Pyrrolidines / Q000494:pharmacology*; D011817:Rabbits; D012163:Retinal Detachment / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000378:metabolism; D018630:Vitreoretinopathy, Proliferative / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*
D005353:Fibronectins; D039081:Integrin alpha5beta1; C545763:JSM6427; D011422:Propionates; D011725:Pyridines; D011759:Pyrrolidines