['Matrix stiffness is recognized increasingly as a significant factor in cell and tissue function. To understand better the mechanosensitivity of Müller cells and its association with vitreoretinal disorders, we examined morphology, propagation, and expression of genes in Müller cells that were cultured on substrates of varying elastic moduli.', "A conditionally immortalized mouse Müller cell line was cultured on laminin-coated polyacrylamide substrates with calibrated Young's moduli. Glass was used as a control. Phase contrast, fluorescence, and atomic force microscopy were used to study cell morphology and propagation. Expression of extracellular matrix (ECM) genes was analyzed using quantitative reverse-transcription PCR.", 'The adherent area, stiffness, and propagation of Müller cells all are affected by matrix stiffness, but to different extents and with different ranges of sensitivity. Of 85 ECM genes tested 11 showed a continuous >4-fold increase or decrease in mRNA expression as a function of the substrate elastic modulus. The changes were statistically significant in four genes: connective tissue growth factor (Ctgf, P = 0.04), tenascin C (Tnc, P = 0.035), Collagen Iα1 (Col1a1, P = 0.0001), and Collagen IVα3 (Col4a3, P = 0.05), with all showing increased expression on softer substrates.'] Is muller cell expression of genes implicated in proliferative vitreoretinopathy influenced by substrate elastic modulus?