title: Apoptosis of hippocampal neurons in organotypic slice culture models: direct effect of bacteria revisited.
abstract: Neurons of the hippocampal dentate gyrus selectively undergo programmed cell death in patients suffering from bacterial meningitis and in experimental models of pneumococcal meningitis in infant rats. In the present study, a membrane-based organotypic slice culture system of rat hippocampus was used to test whether this selective vulnerability of neurons of the dentate gyrus could be reproduced in vitro. Apoptosis was assessed by nuclear morphology (condensed and fragmented nuclei), by immunochemistry for active caspase-3 and deltaC-APP, and by proteolytic caspase-3 activity. Co-incubation of the cultures with live pneumococci did not induce neuronal apoptosis unless cultures were kept in partially nutrient-deprived medium. Complete nutrient deprivation alone and staurosporine independently induced significant apoptosis, the latter in a dose-response way. In all experimental settings, apoptosis occurred preferentially in the dentate gyrus. Our data demonstrate that factors released by pneumococci per se failed to induce significant apoptosis in vitro. Thus, these factors appear to contribute to a multifactorial pathway, which ultimately leads to neuronal apoptosis in bacterial meningitis.
authors.affiliation: Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Gianinazzi
authors.forename: Denis
authors.initials: D
authors.lastname: Grandgirard
authors.forename: Franziska
authors.initials: F
authors.lastname: Simon
authors.forename: Hans
authors.initials: H
authors.lastname: Imboden
authors.forename: Philipp
authors.initials: P
authors.lastname: Joss
authors.forename: Martin G
authors.initials: MG
authors.lastname: Täuber
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Leib
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003470:Culture Media / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000382:microbiology; D007150:Immunohistochemistry; D016920:Meningitis, Bacterial / Q000382:microbiology / Q000473:pathology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000382:microbiology; D009924:Organ Culture Techniques; D051381:Rats; D017208:Rats, Wistar; D019311:Staurosporine / Q000494:pharmacology; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000254:growth & development
chemical_list: D003470:Culture Media; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D019311:Staurosporine