Changes in L-arginine metabolism by Sema4D deficiency induce promotion of microglial proliferation in ischemic cortex. (15th May 2019)

• Record Type: Journal Article
• Authors: Sawano, Toshinori; Tsuchihashi, Ryo; Watanabe, Fumiya; Niimi, Kenta; Yamaguchi, Wataru; Yamaguchi, Natsumi; Furuyama, Tatsuo; Tanaka, Hidekazu; Matsuyama, Tomohiro; Inagaki, Shinobu
• Is Part Of: Neuroscience. Volume 406(2019)
• Page Start: 420
• Page End: 431
• Publication Date: 2019-05-15
• Subjects: Arg arginase -- BrdU 5-bromo-2-deoxyuridine -- Cad cadaverine -- CNS central nervous system -- DMEM Dulbecco's modified Eagle's medium -- DW distilled water -- EDTA ethylenediaminetetraacetic acid -- Iba1 ionized calcium-binding adaptor molecule 1 -- IHC immunohistochemistry -- iNOS inducible nitric oxide synthase -- LPS lipopolysaccharide -- MCA middle cerebral artery -- MCAO middle cerebral artery occlusion -- MTT 3-(4, 5-dimethylthiazol-2-yl)-2, 2-diphenyltetrazolium bromide -- NO nitric oxide -- Nonope non-operated -- OAZ ornithine decarboxylase antienzyme -- ODC ornithine decarboxylase -- POD postoperative day -- Put putrescine -- Sema4D−/− Sema4D-deficient -- Spd spermidine -- SPDS spermidine synthase -- Spm spermine -- SPMS spermine synthase -- TCA trichloroacetic acid -- TLC thin-layer chromatographic -- WT wild-type; microglia -- proliferation -- polyamines -- iNOS -- Arg1 -- MCAO; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2019.03.037
• Languages: English
• ISSNs: 0306-4522

Abstract

Abstract: Cerebral ischemia induces neuroinflammation and microglial activation, in which activated microglia upregulate their proliferative activity and change their metabolic states. In activated microglia, l-arginine is metabolized competitively by inducible nitric oxide synthase (iNOS) and arginase (Arg), which then synthesize NO or polyamines, respectively. Our previous study demonstrated that Sema4D deficiency inhibits iNOS expression and promotes proliferation of ionized calcium-binding adaptor molecule 1 (Iba1)-positive (Iba1 +) microglia in the ischemic cortex, although the underlying mechanisms were unclear. Using middle cerebral artery occlusion, we tested the hypothesis that Sema4D deficiency alters the balance of l-arginine metabolism between iNOS and Arg, leading to an increase in the production of polyamines, which are an essential factor for cell proliferation. In the peri-ischemic cortex, almost all iNOS + and/or Arg1 + cells were Iba1 + microglia. In the peri-ischemic cortex of Sema4D-deficient (Sema4D −/− ) mice, the number of iNOS + Arg1 − Iba1 + microglia was smaller and that of iNOS − Arg1 + Iba1 + microglia was greater than those of wild-type (WT) mice. In addition, urea and polyamine levels in the ischemic cortex of Sema4D −/− mice were higher than those of WT mice; furthermore, the presence of Sema4D inhibited polyamine production in primary microglia obtained from Sema4D −/− mice. Finally, microglia cultured under polyamine putrescine-supplemented conditions demonstrated increased proliferation rates over non-supplemented controls. These findings indicate that Sema4D regulates microglial proliferation at least in part by regulating the competitive balance of l-arginine metabolism. Highlights: Sema4D deficiency promotes microglial proliferation after cerebral ischemia. Sema4D deficiency shifts the l-arginine metabolism of microglia to polyamine production in the ischemic cortex. The polyamine putrescine promotes microglial proliferation in vitro .