title: Exogenous spermine inhibits the proliferation of human pulmonary artery smooth muscle cells caused by chemically-induced hypoxia via the suppression of the ERK1/2- and PI3K/AKT-associated pathways.
abstract: Pulmonary vascular remodeling is a significant pathological feature of hypoxia-induced pulmonary hypertension (HPH), while pulmonary artery smooth muscle cell (PASMC) proliferation plays a leading role in pulmonary vascular remodeling. Spermine (Sp), a polyamine, plays a critical role in periodic cell proliferation and apoptosis. The present study was conducted to observe the association between hypoxia-induced PASMC proliferation and polyamine metabolism, and to explore the effects of exogenous Sp on PASMC poliferation and the related mechanisms. In the present study, PASMCs were cultured with cobalt chloride (CoCl2) to establish a hypoxia model, and Sp at various final concentrations (0.1, 1, 10 and 100 µM) was added to the medium of PASMCs 40 min prior to the induction of hypoxia. Cell proliferation was measured by 3-(4,5-dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide (MTT) assay, cell counting kit-8 assay and 5-bromo‑2'‑deoxyuridine (BrdU) incorporation assay. Cell cycle progression was determined by flow cytometry, and the protein expression levels of spermidine/spermine N1-acetyltransferase (SSAT; the key enzyme in the terminal degradation of polyamine), ornithine decarboxylase (ODC; the key enzyme of polyamine biosynthesis), cyclin D1 and p27 were measured by western blot analysis. The results revealed that the proliferation of the PASMCs cultured with CoCl2 at 50 µM for 24 h markedly increased. The expression of ODC was decreased and the expression of SSAT was increased in the cells under hypoxic conditions. Exogenous Sp at concentrations of 1 and 10 µM significantly inhibited hypoxia-induced PASMC proliferation, leading to cell cycle arrest at the G1/G0 phase. In addition, Sp decreased cyclin D1 expression, increased p27 expression, and suppressed the phosphorylation of extracellular signal‑regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT); however, the above-metioned parameters were not markedly affected by Sp at concentrations of 0.1 or 100 µM. These results suggest that hypoxia disrupts polyamine metabolism, and Sp at concentrations of 1 and 10 µM inhibits the increase in human PASMC proliferation caused by chemically-induced hypoxia via the suppression of the ERK1/2- and PI3K/AKT-associated pathways. This study thus offer new insight into the prevention and treatment of HPH.
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Can
authors.initials: C
authors.lastname: Wei
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Hong-Zhu
authors.initials: HZ
authors.lastname: Li
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yue-Hong
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Xue
authors.initials: X
authors.lastname: Peng
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Hong-Jiang
authors.initials: HJ
authors.lastname: Shao
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Li
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Shu-Zhi
authors.initials: SZ
authors.lastname: Bai
authors.affiliation: Department of Ultrasound, The First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang 154007, P.R. China.
authors.forename: Xiao-Xiao
authors.initials: XX
authors.lastname: Lu
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Wu
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Xu
mesh_terms: D059447:Cell Cycle Checkpoints; D002460:Cell Line; D049109:Cell Proliferation; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000378:metabolism; D000860:Hypoxia / Q000139:chemically induced / Q000150:complications / Q000378:metabolism; D020935:MAP Kinase Signaling System; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000378:metabolism; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011651:Pulmonary Artery / Q000166:cytology* / Q000378:metabolism; D015398:Signal Transduction; D013096:Spermine / Q000378:metabolism*
chemical_list: D013096:Spermine; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt