title: Aging alters vascular mechanotransduction: pressure-induced regulation of p70S6k in the rat aorta.
abstract: Physical forces are important regulators of vascular structure and function though it is unknown how aging may affect the ability of the vasculature to respond to mechanical stimuli. We investigated the pressure-induced activation of ribosomal S6-kinase (p70S6k) and its pathway-related proteins (Akt, GSK-3beta, SHP-2, PTEN) in aortae from young adult (6 month), aged (30 month), and very aged (36 month) Fischer 344 x Brown Norway F1 hybrid rats. With aging, the aortic tissue content of Akt. SHP-2, and PTEN was significantly increased while total p70S6k and GSK-3beta were unchanged. By comparison, the basal phosphorylation of p70S6k at Thr 389 and Thr 421/Ser 424 was increased ( approximately 40%) and unchanged, respectively, while Akt decreased (approximately 37%), GSK-3beta was unchanged, SHP-2 increased (approximately 73.5%), and PTEN increased (approximately 120%) in the aortae of very aged rats. Acute pressurization of aortae resulted in similar increases in phosphorylation of Akt among the different age groups. By comparison, pressure-induced phosphorylation of p70S6k at Thr 389, GSK-3beta and SHP-2 decreased; whereas, PTEN dephosphorylation was increased in 36-month versus 6-month aortae. The results indicate marked alterations in the p70S6k signaling pathway with aging. The implications of these findings on age-associated vessel remodeling are discussed.
authors.affiliation: Department of Biological Sciences, Laboratory of Molecular Physiology, Suite 311, Science Building, 1 John Marshall Drive, Marshall University, Huntington, WV 25755-1090, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Rice
authors.forename: R S
authors.initials: RS
authors.lastname: Kinnard
authors.forename: G L
authors.initials: GL
authors.lastname: Wright
authors.forename: E R
authors.initials: ER
authors.lastname: Blough
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D000818:Animals; D001011:Aorta / Q000033:anatomy & histology / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D051057:Proto-Oncogene Proteins c-akt; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D038362:Glycogen Synthase Kinase 3; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat; D051059:PTEN Phosphohydrolase; C487216:Pten protein, rat