Oncotarget

Research Papers:

STAT3-mediated activation of miR-21 is involved in downregulation of TIMP3 and neovascularization in the ischemic retina

Diana R. Gutsaeva, Menaka Thounaojam, Shubhra Rajpurohit, Folami L. Powell, Pamela M. Martin, Stephanie Goei, Michael Duncan and Manuela Bartoli _

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Oncotarget. 2017; 8:103568-103580. https://doi.org/10.18632/oncotarget.21592

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Abstract

Diana R. Gutsaeva1, Menaka Thounaojam1, Shubhra Rajpurohit1, Folami L. Powell2, Pamela M. Martin2, Stephanie Goei1, Michael Duncan3 and Manuela Bartoli1

1Department of Ophthalmology, Augusta University, Augusta, GA 30912, USA

2Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912, USA

3Department of Internal Medicine, Section of Gastroenterology, Augusta University, Augusta, GA 30912, USA

Correspondence to:

Manuela Bartoli, email: [email protected]

Diana R. Gutsaeva, email: [email protected]

Keywords: ischemic retinopathies, retinal neovascularization, STAT3, miR-21, TIMP3

Received: August 01, 2017     Accepted: September 15, 2017     Published: October 06, 2017

ABSTRACT

Retinal neovascularization (RNV) is a sight threatening complication of ischemic retinopathies with limited therapeutic options. The transcription factor signal transducer and activator of transcription 3 (STAT3) has been shown to play a crucial role in promoting RNV. However, manipulating of STAT3 activity can cause significant adverse side effects due to its neurotrophic properties. In this study, we identified microRNA-21 (miR-21) as a downstream effector of STAT3 activity in the ischemic retinas and determined its role in promoting RNV through inhibition of its molecular target, the tissue inhibitor of matrix metalloproteinases 3 (TIMP3). Using human retinal endothelial cells (HREC) exposed to hypoxia and a mouse model of oxygen-induced retinopathy (OIR), we found that TIMP3 expression was significantly decreased at both mRNA and protein levels and this paralleled the activation of STAT3 and up-regulation of miR-21. Moreover, TIMP3 expression was restored by knockdown of STAT3 or blocking of miR-21 in HREC, thus, confirming TIMP3 as a downstream target of STAT3/miR-21 pathway. Finally, in a mouse model of OIR, blockade of miR-21 by a specific antisense (a.miR-21), halted RNV and this effect was associated with rescuing of TIMP3 expression. Our data show that miR-21 mediates STAT3 pro-angiogenic effects in the ischemic retina, thus suggesting its blockade as a potential therapy to prevent/halt RNV.


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