Characterization of a spontaneously immortalized murine Müller glial cell line QMMuC-1

Purpose: Müller glia are critical for the survival of retinal neurons and the integrity of retinal blood vessels. Müller glial cultures are important tools for investigating Müller glial pathophysiology. Here we report a spontaneously immortalized Müller glial cell line originally cultured and subsequently cloned from mouse pups. The cell line, QMMuC-1, has been cultured for over 60 passages, has morphological features like primary Müller cell (PMC) cultures and remains stable.

Methods: QMMuC-1 and PMC cells were processed for immunohistochemistry, quantitative RT-PCR, western blotting, whole cell voltage-clamping and bioenergetic profiling.

Results: Immunocytochemistry showed that QMMuC-1 express known Müller glial markers including Glutamine Synthetase, Gfap, alpha-smooth muscle actin, Aquaporin 4, Kir4.1, Il33 and Sox2, but not Cone arrestin, Calbindin 1, Cd68 and Iba1. Compared to primary Müller cells (PMC), QMMuC-1 express higher levels of Ccl2, Vegfa and GLAST, but lower levels of Il6, Bdnf, Igf1 and Ntf3. Whole-cell patch clamp recordings demonstrated characteristic inward currents in response to L-Glutamate and L-trans-Pyrrolidine-2,4-dicarboxylic acid (PDC) by QMMuC-1 cells. Bioenergetic profiling studies revealed similar levels of glycolysis and basal mitochondrial respiration between QMMuC-1 and PMC. However, mitochondrial spare capacity was significantly lower in QMMuC-1 as compared to PMC.

Conclusions: Our results suggest that the QMMuC-1 Müller glial cell line retains key characteristics of PMC with its unique profiles in cytokine/neurotrophic factor expression and mitochondrial respiration. QMMuC-1 has utility as an invaluable tool for understanding the role of Müller glia in physiological and pathological conditions.