5-Lipoxygenase is required for proliferation of immature cerebellar granule neurons in vitro

Primary cultures of rat cerebellar granule neurons express 5-lipoxygenase, an enzyme from the inflammatory pathway of arachidonic acid. Outside the ce ntral nervous system (CNS) 5-lipoxygenase participates in cell proliferatio n We hypothesized that 5-lipoxygenase is needed for proliferation of immatu re cerebellar granule neurons. Using cultures prepared from 7-day-old rat p ups, we confirmed in vitro neurogenesis by immunocytolabeling with 2-bromo- 5-deoxyuridine and beta -tubulin isotype III and quantified the rate of cel l proliferation by assaying [H-3]thymidine incorporation. We found that imm ature cerebellar granule neurons express large amounts of 5-lipoxygenase, a nd that treatment with a 5-lipoxygenase antisense, to reduce expression of this gene, decreased significantly (by 60%) the content of 5-lipoxygenase p rotein and effectively reduced cell proliferation. [H-3]thymidine incorpora tion was significantly reduced by each of the three 5-lipoxygenase inhibito rs we tested: AA-861 [2-(12-hydroxydodeca-5, 10-diynyl)-3,5,6-trimethyl-1,4 -benzoquinone], MK-886 (C27H33ClNO2S . Na), and L-655,238 [alpha -penyl-3-( 2-quinolinylmethoxy)-benzenemethanol]. Their anti-proliferative effect was reversible. We propose that neuronal expression of 5-lipoxygenase is crucia l for neurogenesis in vitro, and possibly also in vivo. (C) 2001 Elsevier S cience B.V. All rights reserved.