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Diabetic retinopathy and transcriptional regulation of a small molecular weight G-Protein, Rac1

Renu A Kowluru1, Manish Mishra1, Binit Kumar1

  • 1Kresge Eye Institute, Wayne State University, Detroit, MI, USA.

Experimental Eye Research
|April 26, 2016
PubMed

Insights

Diabetic retinopathy involves retinal cell damage from reactive oxygen species. This study shows NF-kB acetylation drives Rac1 gene activation, offering a potential therapeutic target for diabetic eye disease.

Area of Science:

  • Ophthalmology
  • Molecular Biology
  • Diabetology

Background:

  • Diabetic retinopathy (DR) causes retinal capillary cell apoptosis via mitochondrial damage from reactive oxygen species (ROS) produced by NADPH oxidase (Nox).
  • Rac1 GTPase activates Nox2, and its activation in the retina is implicated in diabetes-induced DR.
  • Understanding the transcriptional regulation of Rac1 in DR is crucial for developing targeted therapies.

Purpose of the Study:

  • To elucidate the molecular mechanism behind the transcriptional activation of Rac1 in the retina during diabetic retinopathy.
  • To investigate the role of nuclear transcriptional factor-kappa B (NF-kB) and its acetylation status in regulating Rac1 expression in diabetes.

Main Methods:

  • Utilized retinal microvessels from streptozotocin-induced diabetic rats to examine NF-kB binding to the Rac1 promoter.
  • Investigated the impact of Sirtuin 1 (a deacetylase) overexpression on NF-kB acetylation and Rac1 transcription in retinas of diabetic mice.
  • Assessed mitochondrial damage mediated by the Rac1-Nox2 pathway.

Main Results:

  • Diabetes significantly increased the binding of the NF-kB p65 subunit to the Rac1 promoter in retinal microvessels.
  • Overexpression of Sirtuin 1 inhibited p65 hyper-acetylation, reduced its binding to the Rac1 promoter, and ameliorated Rac1-Nox2-mediated mitochondrial damage.
  • Confirmed that Rac1 transcriptional activation in the diabetic retina is linked to NF-kB acetylation.

Conclusions:

  • Transcriptional activation of Rac1 in the retina during diabetes is mediated by the acetylation of NF-kB.
  • Modulating NF-kB acetylation presents a promising therapeutic strategy to inhibit or slow the progression of early-stage diabetic retinopathy.
Keywords:
AcetylationDiabetic retinopathyRac1Sirtuin 1Transcriptional regulation

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