Genomic and morphological changes of neuroblastoma cells in response to three-dimensional matrices.

Advances in neural tissue engineering require a comprehensive understanding of neuronal growth in 3 dimensions. This study compared the gene expression of SH-SY5Y human neuroblastoma cells cultured in 3-dimensional (3D) with those cultured in 2-dimensional (2D) environments. Microarray analysis demonstrated that, in response to varying matrix geometry, SH-SY5Y cells exhibited differential expression of 1,766 genes in collagen I, including those relevant to cytoskeleton, extracellular matrix, and neurite outgrowth. Cells extended longer neurites in 3D collagen I cultures than in 2D. Real-time reverse transcriptase polymerase chain reaction experiments and morphological analysis comparing collagen I and Matrigel tested whether the differential growth and gene expression reflected influences of culture dimension or culture material. SH-SY5Y neuroblastoma cells responded to geometry by differentially regulating cell spreading and genes associated with actin in similar patterns for both materials; however, neurite outgrowth and the expression of the gene encoding for neurofilament varied with the type of material. Electron microscopy and mechanical analysis showed that collagen I was more fibrillar than Matrigel, with larger inter-fiber distance and higher stiffness. Taken together, these results suggest complex cell-material interactions, in which the dimension of the culture material influences gene expression and cell spreading and the structural and mechanical properties of the culture material influence gene expression and neurite outgrowth.

CXCR3-dependent recruitment of antigen-specific T lymphocytes to the liver during murine cytomegalovirus infection.

Innate inflammatory events promoting antiviral defense in the liver against murine cytomegalovirus (MCMV) infection have been characterized. However, the mechanisms that regulate the selective recruitment of inflammatory T lymphocytes to the liver during MCMV infection have not been defined. The studies presented here demonstrate the expression of monokine induced by gamma interferon (IFN-gamma; Mig/CXCL9) and IFN-gamma-inducible protein 10 (IP-10/CXCL10) in liver leukocytes and correlate their production with the infiltration of MCMV-specific CD8 T cells into the liver. Antibody-mediated neutralization of CXCL9 and CXCL10 and studies using mice deficient in CXCR3, the primary known receptor for these chemokines, revealed that CXCR3-dependent mechanisms promote the infiltration of virus-specific CD8 T cells into the liver during acute infection with MCMV. Furthermore, CXCR3 functions augmented the hepatic accumulation of CD8 T-cell IFN-gamma responses to MCMV. Evaluation of protective functions demonstrated enhanced pathology that overlapped with transient increases in virus titers in CXCR3-deficient mice. However, ultimate viral clearance and survival were not compromised. Thus, CXCR3-mediated signals support the accumulation of MCMV-specific CD8 T cells that contribute to, but are not exclusively required for, protective responses in a virus-infected tissue site.