title: The functional genome of CA1 and CA3 neurons under native conditions and in response to ischemia.
abstract: BACKGROUND
  The different physiological repertoire of CA3 and CA1 neurons in the hippocampus, as well as their differing behaviour after noxious stimuli are ultimately based upon differences in the expressed genome. We have compared CA3 and CA1 gene expression in the uninjured brain, and after cerebral ischemia using laser microdissection (LMD), RNA amplification, and array hybridization.
  
  
  RESULTS
  Profiling in CA1 vs. CA3 under normoxic conditions detected more than 1000 differentially expressed genes that belong to different, physiologically relevant gene ontology groups in both cell types. The comparison of each region under normoxic and ischemic conditions revealed more than 5000 ischemia-regulated genes for each individual cell type. Surprisingly, there was a high co-regulation in both regions. In the ischemic state, only about 100 genes were found to be differentially expressed in CA3 and CA1. The majority of these genes were also different in the native state. A minority of interesting genes (e.g. inhibinbetaA) displayed divergent expression preference under native and ischemic conditions with partially opposing directions of regulation in both cell types.
  
  
  CONCLUSIONS
  The differences found in two morphologically very similar cell types situated next to each other in the CNS are large providing a rational basis for physiological differences. Unexpectedly, the genomic response to ischemia is highly similar in these two neuron types, leading to a substantial attenuation of functional genomic differences in these two cell types. Also, the majority of changes that exist in the ischemic state are not generated de novo by the ischemic stimulus, but are preexistant from the genomic repertoire in the native situation. This unexpected influence of a strong noxious stimulus on cell-specific gene expression differences can be explained by the activation of a cell-type independent conserved gene-expression program. Our data generate both novel insights into the relation of the quiescent and stimulus-induced transcriptome in different cells, and provide a large dataset to the research community, both for mapping purposes, as well as for physiological and pathophysiological research.
authors.affiliation: Sygnis Bioscience, Im Neuenheimer Feld 515, 69120 Heidelberg, Germany. Newrzella@Sygnis.de
authors.forename: Dieter
authors.initials: D
authors.lastname: Newrzella
authors.forename: Payam S
authors.initials: PS
authors.lastname: Pahlavan
authors.forename: Carola
authors.initials: C
authors.lastname: Krüger
authors.forename: Christine
authors.initials: C
authors.lastname: Boehm
authors.forename: Oliver
authors.initials: O
authors.lastname: Sorgenfrei
authors.forename: Helmut
authors.initials: H
authors.lastname: Schröck
authors.forename: Gisela
authors.initials: G
authors.lastname: Eisenhardt
authors.forename: Nadine
authors.initials: N
authors.lastname: Bischoff
authors.forename: Gerhard
authors.initials: G
authors.lastname: Vogt
authors.forename: Oliver
authors.initials: O
authors.lastname: Wafzig
authors.forename: Moritz
authors.initials: M
authors.lastname: Rossner
authors.forename: Martin H
authors.initials: MH
authors.lastname: Maurer
authors.forename: Holger
authors.initials: H
authors.lastname: Hiemisch
authors.forename: Alfred
authors.initials: A
authors.lastname: Bach
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kuschinsky
authors.forename: Armin
authors.initials: A
authors.lastname: Schneider
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000235:genetics*; D020869:Gene Expression Profiling; D016678:Genome; D007150:Immunohistochemistry; D009474:Neurons / Q000378:metabolism*; D051381:Rats