Project description:Three cell types, intermediolateral column motoneurons, medial motoneurons, and lateral motoneurons were isolated from a single adult spinal cord using laser capture microscopy. Four hundred captures were collected for each cell type. For a given cell type, RNA was extracted from the 400 captures using an Arcturus picopure kit. RNA was split in half and two targets were produced using a double amplification protocol. Each target was hybridized to Affymetrix chips and signals were normalized with R-pack. Inverse logs are provided. Five animals were used in these experiments, and all three cell types were collected from each animal. Thus, for each cell type, there are five biological replicates, and for each biological replicate there are two technical replicates. In all thirty chips were analyzed. Techinical replicates are indicated as Set 1 and Set 2. Animal numbers are indicated by Pair1 through Pair 5. Keywords: other
Project description:Studies in the developing spinal cord suggest that different motoneuron (MN) cell types express very different genetic programs, but the degree to which adult programs differ is unknown. To compare genetic programs between adult MN columnar cell types, we used laser capture microdissection (LCM) and Affymetrix microarrays to create expression profiles for three columnar cell types: lateral and medial MNs from lumbar segments and sympathetic preganglionic motoneurons located in the thoracic intermediolateral nucleus. A comparison of the three expression profiles indicated that 7% (813/11,552) of the genes showed significant differences in their expression levels. The largest differences were observed between sympathetic preganglionic MNs and the lateral motor column, with 6% (706/11,552) of the genes being differentially expressed. Significant differences in expression were observed for 1.8% (207/11,552) of the genes when comparing sympathetic preganglionic MNs with the medial motor column. Lateral and medial MNs showed the least divergence, with 1.3% (150/11,552) of the genes being differentially expressed. These data indicate that the amount of divergence in expression profiles between identified columnar MNs does not strictly correlate with divergence of function as defined by innervation patterns (somatic/muscle vs. autonomic/viscera). Classification of the differentially expressed genes with regard to function showed that they underpin all fundamental cell systems and processes, although most differentially expressed genes encode proteins involved in signal transduction. Mining the expression profiles to examine transcription factors essential for MN development suggested that many of the same transcription factors participate in combinatorial codes in embryonic and adult neurons, but patterns of expression change significantly
Project description:This study describes a cDNA microarray analysis that compared developing mouse MyoD-/- limb musculature (MyoD-dependent, innervated by Lateral Motor Column motor neurons) and Myf5-/- back (epaxial) musculature (Myf5-dependent, innervated by Medial Motor Column motor neurons) to the control and to each other, at embryonic day 13.5 which coincides with the robust programmed cell death of motor neurons and the inability of myogenesis to undergo its normal progression in the absence of Myf5 and MyoD that at this embryonic day cannot substitute for each other. We wanted to see if/how the myogenic program couples with the neurotrophic one, and also to separate Lateral from Medial column trophic requirements, potentially relevant to Motor Neuron Diseases with the predilection for the Lateral column. Several follow-up steps revealed that Kif5c, Stxbp1 and Polb, differentially expressed in the MyoD-/- limb muscle, and Ppargc1a, Glrb and Hoxd10, differentially expressed in the Myf5-/- back muscle, are actually regulators of motor neuron numbers. We propose a series of follow-up experiments and various ways to consider our current data.
Project description:To determine spinal cord injury (SCI) induced changes in gene expression, laser capture microscopy (LCM) and Affymetrix microarrays were used to profiles three distinct populations of motor neurons (MNs) in five sets of littermates. In each set, one littermate received a lamenectomy (sham operated), and the other received a complete spinal cord transection. Each MN population was caudal to the transection and not axotomized. Thus, MNs in transected animals were responding to two major insults: deafferentation and changing microenvironments due to spreading immune and inflammatory responses. A total of 30 expression profiles from sham operated control animals have been uploaded to GEO database with accession number GSE2595. The current series contains 32 motoneuron expression profiles from spinalized mice. All chips (30 sham + 32 transection) were generated together using RMA in 2004. Experiment Overall Design: In this study we determine SCI induced changes in gene expression in lateral motoneurons (LMN), medial motoneurons (MMN) and intermediolateral column motoneurons (IML). Five sets of male littermates were used in these experiments (sets a-e). In each set, one littermate received a lamenectomy (sham operated), and the other received a complete spinal cord transection. Four of the sets (a-d) consisted of one transect and one littermate sham operated control. The fifth set (e) had an additional transect. All surgeries were performed on postnatal day (P) 24. Three weeks later (P45), the animals were sacrificed and their spinal cords were removed and sectioned for LCM. Each of the three cell types was captured from every animal. The expression profiles of the three classes of MNs were obtained using Affymetrix microarrays.