Muller cells as a source of brain-derived neurotrophic factor in the retina: Noradrenaline upregulates brain-derived neurotrophic factor levels in cultured rat Muller cells

Muller cells, the predominant glial cells in the retina, are thought to play important roles in the survival of retinal neurons. Previous studies have demonstrated that Muller cells express brain-derived neurotrophic factor (BDNF), which has a pronounced neurotrophic effect on retinal ganglion cells. In this study, we investigated whether Muller cells express and release BDNF in culture. Reverse transcriptase-PCR, immunocytochemistry and Western blotting revealed that Muller cells produce BDNF mRNA and protein. Using the enzyme-linked immunosorbant assay, BDNF protein levels in Muller cells and their conditioned medium were quantified, demonstrating that Muller cells produce and release high levels of BDNF. Noradrenaline administration caused an upregulation of BDNF mRNA and protein expression by cultured Muller cells. These results suggest that Muller cells may act as an endogenous source of BDNF in the retina. Furthermore, induction of BDNF expression by adrenergic agonists may provide a therapeutic approach to retinal neurodegenerative disorders.