Ischaemia-induced retinal neovascularisation and diabetic retinopathy in mice with conditional knockout of hypoxia-inducible factor-1 in retinal Müller cells

Diabetologia. 2011 Jun;54(6):1554-66. doi: 10.1007/s00125-011-2081-0. Epub 2011 Mar 1.

Abstract

Aims/hypothesis: Retinal Müller cells are known to produce inflammatory and angiogenic cytokines, which play important roles in diabetic retinopathy. Hypoxia-inducible factor (HIF)-1 has been shown to play a crucial role in retinal inflammation and neovascularisation. We sought to determine the role of Müller cell-derived HIF-1 in oxygen-induced retinopathy (OIR) and diabetic retinopathy using conditional Hif-1α (also known as Hif1a) knockout (KO) mice.

Methods: Conditional Hif-1α KO mice were generated by crossing mice expressing cyclisation recombinase (cre, also known as P1_gp003) in Müller cells with floxed Hif-1α mice and used for OIR and streptozotocin-induced diabetes to induce retinal neovascularisation and inflammation, respectively. Abundance of HIF-1α and pro-angiogenic and pro-inflammatory factors was measured by immunoblotting and immunohistochemistry. Retinal neovascularisation was visualised by angiography and quantified by counting pre-retinal nuclei. Retinal inflammation was evaluated by leucostasis and vascular leakage.

Results: While the Hif-1α KO mice showed significantly decreased HIF-1α levels in the retina, they exhibited no apparent histological or visual functional abnormalities under normal conditions. Compared with wild-type counterparts, Hif-1α KO mice with OIR demonstrated attenuated overproduction of vascular endothelial growth factor (VEGF) and intercellular adhesion molecule (ICAM)-1, reduced vascular leakage and alleviated neovascularisation in the retina. Under diabetes conditions, disruption of Hif-1α in Müller cells attenuated the increases of retinal vascular leakage and adherent leucocytes, as well as the overproduction of VEGF and ICAM-1.

Conclusions/interpretation: Müller cell-derived HIF-1α is a key mediator of retinal neovascularisation, vascular leakage and inflammation, the major pathological changes in diabetic retinopathy. Müller cell-derived HIF-1α is therefore a promising therapeutic target for diabetic retinopathy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiography
  • Animals
  • Diabetes Mellitus, Experimental / chemically induced
  • Diabetes Mellitus, Experimental / complications
  • Diabetes Mellitus, Experimental / metabolism*
  • Diabetic Retinopathy / etiology*
  • Diabetic Retinopathy / metabolism
  • Diabetic Retinopathy / physiopathology
  • Disease Models, Animal
  • Hypoxia-Inducible Factor 1, alpha Subunit / deficiency*
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Integrases / metabolism
  • Intercellular Adhesion Molecule-1 / metabolism
  • Ischemia / complications*
  • Ischemia / metabolism
  • Ischemia / physiopathology
  • Leukostasis / metabolism
  • Leukostasis / physiopathology
  • Male
  • Mice
  • Mice, Knockout
  • Retina / metabolism*
  • Retina / pathology
  • Retinal Neovascularization / etiology*
  • Retinal Neovascularization / metabolism
  • Retinal Neovascularization / physiopathology
  • Retinal Vessels / diagnostic imaging
  • Retinal Vessels / metabolism
  • Retinal Vessels / physiopathology*
  • Streptozocin / adverse effects
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Hif1a protein, mouse
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Vascular Endothelial Growth Factor A
  • Intercellular Adhesion Molecule-1
  • Streptozocin
  • Cre recombinase
  • Integrases