title: Upregulation of FLJ10540, a PI3K-association protein, in rostral ventrolateral medulla impairs brain stem cardiovascular regulation during mevinphos intoxication.
abstract: FLJ10540, originally identified as a microtubule-associated protein, induces cell proliferation and migration during tumorigenesis via the formation of FLJ10540-PI3K complex and enhancement of PI3K kinase activity. Interestingly, activation of PI3K/Akt cascade, leading to upregulation of nitric oxide synthase II (NOS II)/peroxynitrite signaling in the rostral ventrolateral medulla (RVLM), the brain stem site that maintains blood pressure and sympathetic vasomotor tone, mediates the impairment of brain stem cardiovascular regulation induced by the pesticide mevinphos. We evaluated the hypothesis that upregulation of FLJ10540 in the RVLM is upstream to this repertoire of signaling cascade that underpins mevinphos-induced circulatory depression. Microinjection bilaterally of mevinphos (10nmol) into the RVLM of anesthetized Sprague-Dawley rats induced a progressive hypotension that was accompanied by an increase (Phase I), followed by a decrease (Phase II) of an experimental index for baroreflex-mediated sympathetic vasomotor tone. There was augmentation in FLJ10540 mRNA in the RVLM or FLJ10540 protein in RVLM neurons, both of which were causally and temporally related to an augmentation of binding between the catalytic subunit (p110) and regulatory subunit (p85) of PI3K, phosphorylation of Akt at Thr308 site, and NOS II, superoxide or peroxynitrite level in the RVLM. Immunoneutralization of FJL10540 in the RVLM significantly antagonized those biochemical changes, and blunted the progressive hypotension and the reduced baroreflex-mediated sympathetic vasomotor tone during mevinphos intoxication. We conclude that upregulation of FLJ10540 in the RVLM elicits impairment of brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication via activation of PI3K/Akt/NOS II/peroxynitrite signaling cascade in the RVLM.
authors.affiliation: Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China.
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Tsai
authors.affiliation: Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China.
authors.forename: Chang-Han
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Institute of Physiology, National Cheng Kung University, Tainan, Taiwan, Republic of China.
authors.forename: Alice Y W
authors.initials: AY
authors.lastname: Chang
authors.affiliation: Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China.
authors.forename: Julie Y H
authors.initials: JY
authors.lastname: Chan
authors.affiliation: Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China. Electronic address: shhchan@cgmh.org.tw.
authors.forename: Samuel H H
authors.initials: SH
authors.lastname: Chan
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000378:metabolism; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism*; D008799:Mevinphos / Q000633:toxicity*; D009687:Nuclear Proteins / Q000096:biosynthesis*; D019869:Phosphatidylinositol 3-Kinases / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; C505378:Cep55 protein, human; D009687:Nuclear Proteins; D008799:Mevinphos; D019869:Phosphatidylinositol 3-Kinases
keywords: Brain stem cardiovascular regulation; FLJ10540; Organophosphate intoxication; PI3K/Akt signaling; Rostral ventrolateral medulla