Sirtuin 1 regulates pulmonary artery smooth muscle cell proliferation: role in pulmonary arterial hypertension
JOURNAL OF HYPERTENSION
Authors: Zurlo, Giada; Piquereau, Jerome; Moulin, Maryline; Da Silva, Julie Pires; Gressette, Melanie; Ranchoux, Benoit; Garnier, Anne; Ventura-Clapier, Renee; Fadel, Elie; Humbert, Marc; Lemaire, Christophe; Perros, Frederic; Veksler, Vladimir
Abstract
Objective:Energy metabolism shift from oxidative phosphorylation toward glycolysis in pulmonary artery smooth muscle cells (PASMCs) is suggested to be involved in their hyperproliferation in pulmonary arterial hypertension (PAH). Here, we studied the role of the deacetylase sirtuin1 (SIRT1) in energy metabolism regulation in PASMCs via various pathways including activation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1), master regulator of mitochondrial biogenesis.Approach and results:Contents of PGC-1 and its downstream targets as well as markers of mitochondrial mass (voltage-dependent anion channel and citrate synthase) were diminished in human PAH PASMCs. These cells and platelet-derived growth factor-stimulated rat PASMCs demonstrated a shift in cellular acetylated/deacetylated state, as evidenced by the increase of the acetylated forms of SIRT1 targets: histone H1 and Forkhead box protein O1. Rat and human PASMC proliferation was potentiated by SIRT1 pharmacological inhibition or specific downregulation via short-interfering RNA. Moreover, after chronic hypoxia exposure, SIRT1 inducible knock out mice displayed a more intense vascular remodeling compared with their control littermates, which was associated with an increase in right ventricle pressure and hypertrophy. SIRT1 activator Stac-3 decreased the acetylation of histone H1 and Forkhead box protein O1 and strongly inhibited rat and human PASMC proliferation without affecting cell mortality. This effect was associated with the activation of mitochondrial biogenesis evidenced by higher expression of mitochondrial markers and downstream targets of PGC-1.Conclusion:Altered acetylation/deacetylation balance as the result of SIRT1 inactivation is involved in the pathogenesis of PAH, and this enzyme could be a promising therapeutic target for PAH treatment.
Passive microwave remote sensing for estimation of rice water content in Vietnam
IGARSS 2003: IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, VOLS I - VII, PROCEEDINGS: LEARNING FROM EARTH'S SHAPES AND SIZES
Authors: Chung, DM; Trong, BD; Anh, VTL
Abstract
Rice is one of the world's, major staple foods that accounts for 15% of the world's total cultivated area In Asia where 94% of the world's rice is produced, rice is the main source of food and a significant source of income. In Vietnam, rice cultivated area occupies 47% of agricultural land of the country. Rice growing conditions are-essential for crop monitoring, yield prediction while rice water content decides the evolutional process and yield per year of the crop. A model for passive microwave emission from water-rice fields, i.e. rice planted on a water layer, is presented in the paper. Field experiments carried out by scientists. of Space Technology Application Centre (STAC), Institute of Physics. National Centre for Natural Science and Technology of Vietnam (NCST) using L- & C-band radiometers on water-rice fields are described. An estimation of the rice water content was made that well agreed to ones received by direct measurements. The results are interesting and useful for crop monitoring of agricultural services.