Interleukin-6 (IL-6) production by cytokine-stimulated human Muller cells

Purpose. To investigate whether or not human Muller cells synthesize interleukin (IL)-6. Methods. Using RT-PCR, we first confirmed whether cultured human Muller cells express IL-6 mRNA. Then, to determine Muller cell IL-6 production after stimulation, cultured Muller cells were exposed to various concentrations of IL-1 beta (0.2 ng/ml, 2 ng/ml, 20 ng/ml) or lipopolysaccharide (LPS) (0.001 mug/ml, 0.1 mug/ml, 10 mug/ml) in 24hr assays. In addition, to determine Muller cell time-dependent induction of IL-6 production, cultured Muller cells were exposed to IL-1 beta (0.02 ng/ml, 2 ng/ml) or LPS (10 mug/ml) for 6, 12, 24, 36hr. IL-6 production in supernatants was quantified by ELISA. Results. IL-6 mRNA was expressed in cultured human Muller cells, which produced IL-6 after stimulation with either IL-10 or LPS for 24 hours. IL-1 beta was a significantly more potent stimulator of IL-6 production than was LPS. Exposure of cultured human Muller cells to either IL-1 beta or LPS stimulated IL-6 production in a time-dependent fashion. Conclusions. Our findings indicate that human Muller cells can produce IL-6 when stimulated by IL-1 beta or LPS. Muller cell IL-6 production may have an important role in various conditions involving ocular inflammation.