Thromboxane-induced actin polymerization in hypoxic pulmonary artery is independent of Rho
| Autor: | Shyamala Dakshinamurti, Nora Nolette, Jena Fediuk, Alexey Gutsol |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Pulmonary and Respiratory Medicine
Swine Physiology Thromboxane G protein Receptors Thromboxane Cell Culture Techniques Aorta Thoracic Pulmonary Artery Biology Persistent Fetal Circulation Syndrome Renal Artery Physiology (medical) medicine.artery medicine Animals Humans Vasoconstrictor Agents Myocyte Phosphorylation Hypoxia Actin Muscle Cells Aorta Infant Newborn Lim Kinases Thromboxanes Cell Biology Anatomy Hypoxia (medical) Actin cytoskeleton Actins Cell Hypoxia Laser Scanning Cytometry Cell biology Actin Cytoskeleton Disease Models Animal Hypertension Renovascular Animals Newborn Vasoconstriction 15-Hydroxy-11 alpha 9 alpha-(epoxymethano)prosta-5 13-dienoic Acid Pulmonary artery medicine.symptom rhoA GTP-Binding Protein |
| Zdroj: | American Journal of Physiology-Lung Cellular and Molecular Physiology. 302:L13-L26 |
| ISSN: | 1522-1504 1040-0605 |
| Popis: | Actin polymerization (APM), regulated by Rho GTPases, promotes myocyte force generation. Hypoxia is known to impede postnatal disassembly of the actin cytoskeleton in pulmonary arterial (PA) myocytes. We compared basal and agonist-induced APM in myocytes from PA and descending aorta (Ao), under hypoxic and normoxic conditions. We also examined effects of thromboxane challenge on force generation and cytoskeletal assembly in resistance PA and renal arteries from neonatal swine with persistent pulmonary hypertension (PPHN) induced by 72-h normobaric hypoxia, compared with age-matched controls. Synthetic and contractile phenotype myocytes from neonatal porcine PA or Ao were grown in hypoxia (10% O2) or normoxia (21% O2) for 7 days, then challenged with 10−6 M thromboxane mimetic U46619. F/G actin ratio was quantified by laser-scanning cytometry and by cytoskeletal fractionation. Thromboxane receptor (TP) G protein coupling was measured by immunoprecipitation and probing for Gαq, G12, or G13, RhoA activation by Rhotekin-RBD affinity precipitation, and LIM kinase (LIMK) and cofilin phosphorylation by Western blot. Isometric force to serial concentrations of U46619 was measured in muscular pulmonary and renal arteries from PPHN and control swine; APM was quantified in fixed contracted vessels. Contractile PA myocytes exhibit marked Rho-dependent APM in hypoxia, with increased active RhoA and LIMK phosphorylation. Their additional APM response to U46619 challenge is independent of RhoA, reflecting decreased TP association with G12/13 in favor of Gαq. In contrast, hypoxic contractile Ao myocytes polymerize actin modestly and depolymerize to U46619. Both basal APM and the APM response to U46619 are increased in PPHN PA. APM corresponds with increased force generation to U46619 challenge in PPHN PA but not renal arteries. |
| Databáze: | OpenAIRE |
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