title: Expression of prosalusin in human neuroblastoma cells.
abstract: Salusins, which are derived from the prosalusin precursor molecule, regulate hemodynamics, mitogenesis and atherogenesis. The preprosalusin gene is ubiquitously expressed, while the salusin-beta peptide is present in systemic endocrine cells and the neuroendocrine system. However, the regulatory mechanisms for the preprosalusin gene and prosalusin expression remain to be investigated. Real-time quantitative RT-PCR and salusin-alpha radioimmunoassay revealed that the neuroblastoma cell line, SK-N-SH, exhibited marked upregulation of preprosalusin mRNA and salusin-alpha-like immunoreactivity (LI) when incubated under 2% serum condition. However, SK-N-SH cells released a limited amount of salusin-alpha-LI into the culture supernatant. Reverse-phase high performance liquid chromatography coupled with radioimmunoassay after extraction of proteins from the conditioned media using an octyl-silica column did not reveal a component that co-eluted with authentic salusin-alpha. Western blotting of the nuclear extracts from SK-N-SH showed the expression of prosalusin and its cleaved fragments, but not authentic salusin-alpha. Addition of Jak-2 inhibitors to growing SK-N-SH cells cultured under 10% serum condition resulted in increased salusin-alpha-LI expression. Suppression of Jak-2 mRNA using siRNAs upregulated intracellular salusin-alpha-LI, as detected by immunofluorescence. In summary, the preprosalusin gene and prosalusin protein are expressed in a neuroblastoma cell line and upregulated by reduced serum. The Jak-2 pathway may be involved in the regulation of salusin expression.
authors.affiliation: Department of Clinical and Molecular Endocrinology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Chisato
authors.initials: C
authors.lastname: Nakayama
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Shichiri
authors.forename: Kengo
authors.initials: K
authors.lastname: Sato
authors.forename: Yukio
authors.initials: Y
authors.lastname: Hirata
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D005786:Gene Expression Regulation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D011863:Radioimmunoassay
chemical_list: D003470:Culture Media; D036341:Intercellular Signaling Peptides and Proteins; D011498:Protein Precursors; C478739:TOR2A protein, human