title: Involvement of small GTPase RhoA in the regulation of superoxide production in BV2 cells in response to fibrillar Aβ peptides.
abstract: Fibrillar amyloid-beta (fAβ) peptide causes neuronal cell death, which is known as Alzheimer's disease. One of the mechanisms for neuronal cell death is the activation of microglia which releases toxic compounds like reactive oxygen species (ROS) in response to fAβ. We observed that fAβ rather than soluble form blocked BV2 cell proliferation of microglial cell line BV2, while N-acetyl-l-cysteine (NAC), a scavenger of superoxide, prevented the cells from death, suggesting that cell death is induced by ROS. Indeed, both fAβ1-42 and fAβ25-35 induced superoxide production in BV2 cells. fAβ25-35 produced superoxide, although fAβ25-35 is not phagocytosed into BV2 cells. Thus, superoxide production by fAβ does not seem to be dependent on phagocytosis of fAβ. Herein we studied how fAβ produces superoxide in BV2. Transfection of dominant negative (DN) RhoA (N19) cDNA plasmid, small hairpin (sh)-RhoA forming plasmid, and Y27632, an inhibitor of Rho-kinase, abrogated the superoxide formation in BV2 cells stimulated by fAβ. Furthermore, fAβ elevated GTP-RhoA level as well as Rac1 and Cdc42. Tat-C3 toxin, sh-RhoA, and Y27632 inhibited the phosphorylation of p47(PHOX). Moreover, peritoneal macrophages from p47(PHOX) (-/-) knockout mouse could not produce superoxide in response to fAβ. These results suggest that RhoA closely engages in the regulation of superoxide production induced by fAβ through phosphorylation of p47(PHOX) in microglial BV2 cells.
authors.affiliation: Department of Biochemistry, Hallym University, Chuncheon, Kangwon-Do 200-702, Republic of Korea.
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Moon
authors.forename: Hee-Jun
authors.initials: HJ
authors.lastname: Kim
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Jae-Gyu
authors.initials: JG
authors.lastname: Kim
authors.forename: Yee-Jin
authors.initials: YJ
authors.lastname: Jeon
authors.forename: Ha-Young
authors.initials: HY
authors.lastname: Won
authors.forename: Jun-Sub
authors.initials: JS
authors.lastname: Kim
authors.forename: Hyeok-Yil
authors.initials: HY
authors.lastname: Kwon
authors.forename: Ihn-Geun
authors.initials: IG
authors.lastname: Choi
authors.forename: Eusun
authors.initials: E
authors.lastname: Ro
authors.forename: Eun-Hye
authors.initials: EH
authors.lastname: Joe
authors.forename: Myeon
authors.initials: M
authors.lastname: Choe
authors.forename: Hyung-Joo
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Hyoung-Chun
authors.initials: HC
authors.lastname: Kim
authors.forename: Yong-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Jae-Bong
authors.initials: JB
authors.lastname: Park
mesh_terms: D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D051379:Mice; D017628:Microglia / Q000166:cytology* / Q000378:metabolism; D008969:Molecular Sequence Data; D019255:NADPH Oxidases / Q000378:metabolism; D010766:Phosphorylation; D013481:Superoxides / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D013481:Superoxides; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D020742:rhoA GTP-Binding Protein