title: Role of the cell cycle in the pathobiology of central nervous system trauma.
abstract: Upregulation of cell cycle proteins occurs in both mitotic and post-mitotic neural cells after central nervous system (CNS) injury in adult animals. In mitotic cells, such as astroglia and microglia, they induce proliferation, whereas in post-mitotic cells such as neurons they initiate caspase-related apoptosis. We recently reported that early central administration of the cell cycle inhibitor flavopiridol after experimental traumatic brain injury (TBI) significantly reduced lesion volume, scar formation and neuronal cell death, while promoting near complete behavioral recovery. Here we show that in primary neuronal or astrocyte cultures structurally different cell cycle inhibitors (flavopiridol, roscovitine, and olomoucine) significantly reduce upregulation of cell cycle proteins, attenuate neuronal cell death induced by etoposide, and decrease astrocyte proliferation. Flavopiridol, in a concentration dependent manner, also attenuates proliferation/activation of microglia. In addition, we demonstrate that central administration of flavopiridol improves functional outcome in dose-dependent manner after fluid percussion induced brain injury in rats. Moreover, delayed systemic administration of flavopiridol significantly reduces brain lesion volume and edema development after TBI. These data provide further support for the therapeutic potential of cell cycle inhibitors for the treatment of clinical CNS injury and that protective mechanisms likely include reduction of neuronal cell death, inhibition of glial proliferation and attenuation of microglial activation.
authors.affiliation: Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA.
authors.forename: Ibolja
authors.initials: I
authors.lastname: Cernak
authors.forename: Bogdan
authors.initials: B
authors.lastname: Stoica
authors.forename: Kimberly R
authors.initials: KR
authors.lastname: Byrnes
authors.forename: Simone
authors.initials: S
authors.lastname: Di Giovanni
authors.forename: Alan I
authors.initials: AI
authors.lastname: Faden
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001253:Astrocytes / Q000378:metabolism; D001921:Brain / Q000196:embryology; D002453:Cell Cycle; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D002490:Central Nervous System / Q000293:injuries* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004487:Edema; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007701:Kinetin / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D017628:Microglia / Q000378:metabolism; D008938:Mitosis; D009474:Neurons / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology; D011687:Purines / Q000494:pharmacology; D051381:Rats; D000077546:Roscovitine; D015854:Up-Regulation
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010880:Piperidines; D011687:Purines; D000077546:Roscovitine; C077990:alvocidib; C090046:olomoucine; D005047:Etoposide; D007701:Kinetin