Traumatic injury induces differential expression of cell death genes in organotypic brain slice cultures determined by complementary DNA array hybridization

Abstract

Abstract-The expression of a large panel of selected genes hypothesized to play a central role in post-traumatic cell death was shown to be differentially altered in response to a precisely controlled, mechanical injury applied to an organotypic slice culture of the rat brain. Within 48 h of injury, the expression of nerve growth factor messenger RNA was significantly increased whereas the levels of bcl-2, a-subunit of calcium/calmodulin-dependent protein kinase II, cAMP response element binding protein, 65,000 mol. wt isoform of glutamate decarboxylase, 1b isoform of protein kinase C, and ubiquitin messenger RNA were significantly decreased. Because the expression levels of a number of other messenger RNAs such as the neuron-specific amyloid precursor protein, b 2 microglobulin, bax, bcl xl , brain-derived neurotrophic factor, cyclooxygenase-2, interleukin-1b, interleukin-6, tumor necrosis factor-a, receptor tyrosine kinase A, and receptor tyrosine kinase B were unaffected, these selective changes may represent components of an active and directed response of the brain initiated by mechanical trauma.Interpretation of these co-ordinated alterations suggests that mechanical injury to the central nervous system may lead to disruption of calcium homeostasis resulting in altered gene expression, an impairment of intracellular cascades responsible for trophic factor signaling, and initiation of apoptosis via multiple pathways. An understanding of these transcriptional changes may contribute to the development of novel therapeutic strategies to enhance beneficial and blunt detrimental, endogenous, post-injury response mechanisms. ᭧ 2000 IBRO. Published by Elsevier Science Ltd.Key words: genomic expression, in vitro model, traumatic brain injury, organotypic culture, stretch injury, cDNA array.The primary mechanical event associated with traumatic injury to the CNS initiates a cascade of molecular and cellular events which include changes in gene expression, culminating in cell dysfunction and/or death. Although the initial injury occurs in less than 1 s, the post-traumatic sequelae may take hours or days to develop, thereby providing an opportunity to therapeutically attenuate detrimental or augment beneficial endogenous responses in an attempt to limit resultant cell death. A detailed analysis of these specific molecular events may aid in the rational development of novel therapies for the brain-injured patient. Many genes which have been reported to be up-regulated following experimental models of traumatic brain injury (TBI), such as c-fos, c-jun, junB or zif/ 268, 24,54,58,69 are transcription factors that control the expression of other genes, suggesting that the expression of a large number of genes, including those involved in cell death or survival, may be affected by trauma.In this regard, expression of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), necessary for neuronal and other cell survival, has been shown to be increased after controlled cortical impact (CCI) injury in the rat. ...

The Amount of Immature Glial Cells in Organotypic Brain Slices Determines the Susceptibility to Murine Cytomegalovirus Infection

“…Recently, Jin et al (2001) reported that neurogenesis in the SVZ was induced after focal ischemia in the rat. In the brain slice culture system, it was reported that a significant amount of neuronal cell death also occurred during culture (Morrison et al, 2000;Okada et al, 1995), resulting in stimulation of neurogenesis (Biebl et al, 2000). These findings suggest that CMV-susceptible immature glial cells, including neural progenitor cells, may proliferate in damaged brains with neural regeneration, such as the brains of AIDS patients.…”

Neuron-Specific mRNA Complexity Responses during Hippocampal Apoptosis after Traumatic Brain Injury

“…Transcription of the first strand of cDNA was performed in situ to increase the yield of cDNA from the endogenous mRNA pool before microdissection (Crino et al, 1996;Morrison et al, 2000). After TUNEL and active caspase 3 immunohistochemistry, sections were incubated overnight with the oligo-dT primer coupled with a T7 RNA polymerase promoter sequence (oligo-dT-T7), as described previously (Eberwine et al, 1992b;Phillips and Eberwine, 1996).…”

“…These techniques are restricted to the use of tissue homogenates that prevent the localization of the cellular source of the differential expression. The use of amplified antisense mRNA (aRNA) bypasses these restric-tions by allowing the detection of multiple mRNA species within individual cells in culture or fixed tissues (Eberwine et al, 1992b;Crino et al, 1996;Morrison et al, 2000;O'Dell et al, 2000). Recently, this methodology was used to generate an expression profile of apoptotic cortical cells at two time points after experimental brain injury in the rat (O'Dell et al, 2000).…”

Acute Injury to Superficial Cortex Leads to a Decrease in Synaptic Inhibition and Increase in Excitation in Neocortical Layer V Pyramidal Cells

“…In these studies, the presence of acute seizures independently predicts seizure recurrence. Given the rapidity with which injury-induced alterations to physiological and biochemical processes occur in neural circuits (D'Ambrosio and Perucca 2004;Miller et al 1990;Morrison et al 2000;Topolink et al 2003a,b), the plastic changes in cortical function that support epileptogenesis could develop quickly after brain injury. However, in human epidemiologic studies, the role of early seizures is less clear.…”