PT  - JOURNAL ARTICLE
AU  - Sandra S. Hammer
AU  - Cristiano P. Vieira
AU  - Delaney McFarland
AU  - Maximilian Sandler
AU  - Yan Levitsky
AU  - Tim F. Dorweiler
AU  - Todd Lydic
AU  - Bright Asare-Bediako
AU  - Yvonne Adu-Agyeiwaah
AU  - Micheli Severo Sielski
AU  - Mariana Dupont
AU  - Ana Leda Longhini
AU  - Sergio Li Calzi
AU  - Dibyendu Chakraborty
AU  - Gail M. Seigel
AU  - Denis A. Proshlyakov
AU  - Maria B. Grant
AU  - Julia V. Busik
TI  - Pharmacological and fasting-induced activation of SIRT1/LXRα signaling alleviates diabetes-induced retinopathy
AID  - 10.1101/871822
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 871822
4099  - http://biorxiv.org/content/early/2019/12/10/871822.short
4100  - http://biorxiv.org/content/early/2019/12/10/871822.full
AB  - In diabetes, the retina, a tissue with unique metabolic needs, demonstrates dysregulation of the intricate balance between nutrient availability and utilization. This results in cholesterol accumulation, pro-inflammatory and pro-apoptotic changes, and consequently neurovascular damage. Sirtuin 1 (SIRT1), a nutrient sensing deacetylase, is downregulated in the diabetic retina. In this study, the effect of SIRT1 stimulation by fasting or by pharmacological activation using SRT1720, was evaluated on retinal cholesterol metabolism, inflammation and neurovascular damage. SIRT1 activation, in retinal endothelial cells (REC) and neuronal retinal progenitor cells (R28), led to Liver X Receptor alpha (LXRα) deacetylation and subsequent increased activity, as measured by increased ATP-binding cassette transporter (ABC) A1 and G1 mRNA expression. In turn, increased cholesterol export resulted in decreased REC cholesterol levels. SIRT1 activation also led to decreased inflammation. SIRT1 activation, in vivo, prevented diabetes-induced inflammation and vascular and neural degeneration. Diabetes-induced visual function impairment, as measured by electroretinogram and optokinetic response, was significantly improved as a result of SIRT1 activation. Taken together, activation of SIRT1 signaling is an effective therapeutic strategy that provides a mechanistic link between the advantageous effects associated with fasting regimes and prevention of diabetic retinopathy (DR).