Extracellular matrix-associated gene expression in adult sensory neurons cultured on laminin substrates

Background: In our previous investigations of the role of the extracellular matrix (ECM) in promoting neurite growth we have observed that a permissive laminin (LN) substrate stimulates differential growth responses in subpopulations of mature dorsal root ganglion (DRG) neurons. DRG neurons expressing Trk and p75 receptors grow neurites on a LN substrate in the absence of neurotrophins, while isolectin B4-binding neurons (IB4+) do not display significant growth under the same conditions. We set out to determine whether there was an expression signature of the LN-induced neurite growth phenotype. Using a lectin binding protocol IB4+ neurons were isolated from dissociated DRG neurons, creating two groups - IB4+ and IB4-. A small-scale microarray approach was employed to screen the expression of a panel of ECM-associated genes following dissociation (t=0) and after 24 hr culture on LN (t=24LN). This was followed by qRT-PCR and immunocytochemistry of selected genes. Results: The microarray ..., ECM IB4+ t=0 expressed genes reps1-7Data showing genes detected on microarrays for IB4-expressing dorsal root ganglion neurons at t=0 (smapled immediately after selection protocol). See Read-me file for details. Only genes detected above background are listed; of 144 ECM genes on the arrays, only 36 genes were expressed by both neuron populations.ECM IB4+ tECM IB4neg t=0 expressed genes reps1-7Data for non-IB4 expressing DRG neurons at t=0; these were sampled immediately after the selection protocol that removes the IB4-expressing neurons, leaving the IB4-negative neurons behind. Only genes detected as being expressed are presented.Of 144 ECM genes on the arrays, 36 genes were expressed by both neuron populations.ECM IB4neg tECM IB4+ t=24LN expressed genes reps1-6Data showing genes detected on microarrays for IB4-expressing dorsal root ganglion neurons at t=24LN (sampled after 24 hr culture on laminin-coated substrate). See Read-me file for details. Only genes detected above background...,