September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Loss of thioredoxin reductase-1 in the hyperglycemic milieu stimulates retinal vessel senescence and senescence-associated pro-inflammatory phenotype
Author Affiliations & Notes
  • Menaka Thounaojam
    Opthalmology, Georgia Regents University, Augusta, Georgia, United States
  • Folami Lamoke
    Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
  • Diana Gutsaeva
    Opthalmology, Georgia Regents University, Augusta, Georgia, United States
  • Wan Jin Jahng
    Organic Chemistry, Biochemistry, American University of Nigeria, Yola, Nigeria
  • Pamela M Martin
    Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
  • Manuela Bartoli
    Opthalmology, Georgia Regents University, Augusta, Georgia, United States
  • Footnotes
    Commercial Relationships   Menaka Thounaojam, None; Folami Lamoke, None; Diana Gutsaeva, None; Wan Jin Jahng, None; Pamela Martin, None; Manuela Bartoli, None
  • Footnotes
    Support  EY022416
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 3225. doi:
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      Menaka Thounaojam, Folami Lamoke, Diana Gutsaeva, Wan Jin Jahng, Pamela M Martin, Manuela Bartoli; Loss of thioredoxin reductase-1 in the hyperglycemic milieu stimulates retinal vessel senescence and senescence-associated pro-inflammatory phenotype. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3225.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Evidence is provided that capillary loss and pro-inflammatory events in the diabetic retinas are linked to hyperglycemia-induced vascular senescence, through the acquisition of senescence-associated secretory phenotype (SASP). Loss of endogenous antioxidant capacity has been linked to both SASP and progression of diabetic retinopathy (DR). In the present study, we have investigated the specific role of thioredoxin-reductase 1 (TrxR1) in this process in retinal vascular endothelium.

Methods : Experiments were conducted using human post-mortem retinas obtained from Georgia Eye Bank and human retinal endothelial cells (HuREC). HuREC were transfected with siRNA for TrxR-1, non-targeted control siRNA, miR-34a, antagomiR-34a and (human) TrxR-1 plasmid, using liposome-mediated transfection. Activity of TrxR-1 and SIRT-1 were measured using commercially available kits. Western analysis was used to measure protein levels of TrxR-1, SIRT-1 and levels of acetylated p65 NF-kB subunit. Quantitative PCR was used to assess expression of mir-34a and SIRT-1. Senescence-associated-beta-galactosidase (S-A-Beta-Gal) activity was used as marker of senescence-like changes in HuREC.

Results : We have found a marked reduction of TrxR-1 activity in retinas of donors with DR versus control non diabetic donors, but no changes in protein levels. In the same samples loss of TrxR-1 was associated with decreased SIRT-1 expression and activity paralleled by increased acetylation of NF-kB p65 subunit. In HuREC, TrxR-1 silencing resulted in induction of SA-Beta-Gal activity, increased expression of miR-34a and consequent loss of its molecular target SIRT-1and persistent acetylation/activation of the NF-kB p65 subunit. Same effects were also observed in HuREC exposed to high glucose levels (35mM for 72 hours) in comparison to cells exposed to normal glucose (5mM) or osmotic control, however overexpression of (human)TrxR-1 in huREC or transfection with antagomiR-34a rescued SIRT-1 expression and halted high glucose-induced- acetylation of NF-kB p65 subunit and increased S-A-Beta-Gal activity.

Conclusions : Our results disclose a key molecular mechanism underlying retinal vessels dysfunction and inflammation in human DR and proposes maintenance and enhancement of TrxR-1 activity in the diabetic retina as a potential therapeutic goal for the treatment of DR.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

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