TY - JOUR
T1 - Involvement of gap junctions between smooth muscle cells in sustained hypoxic pulmonary vasoconstriction development
T2 - A potential role for 15-HETE and 20-HETE
AU - Kizub, Igor V.
AU - Lakhkar, Anand
AU - Dhagia, Vidhi
AU - Joshi, Sachindra R.
AU - Jiang, Houli
AU - Wolin, Michael S.
AU - Falck, J R
AU - Koduru, Sreenivasulu Reddy
AU - Errabelli, Ramu
AU - Jacobs, Elizabeth R.
AU - Schwartzman, Michal L.
AU - Gupte, Sachin A.
N1 - Funding Information:
This study was supported by The Fulbright Program and the US Department of State?s Bureau of Education and Cultural Affairs (to I. V. Kizub and S. A. Gupte; 2013?2014); National Heart, Lung, and Blood InstituteNHLBI Grants HL- 115124 (to M. S. Wolin), HL-034300 (to M. L. Schwartzman), HL-116530 (to E. R. Jacobs), and HL-111392 (to J. R. Falck); Veterans Administration Merit Review (BX001681 to E. R. Jacobs); and the Robert A. Welch Foundation (I-0011 to J. R. Falck).
Publisher Copyright:
© 2016 the American Physiological Society.
PY - 2016/4/15
Y1 - 2016/4/15
N2 - In response to hypoxia, the pulmonary artery normally constricts to maintain optimal ventilation-perfusion matching in the lung, but chronic hypoxia leads to the development of pulmonary hypertension. The mechanisms of sustained hypoxic pulmonary vasoconstriction (HPV) remain unclear. The aim of this study was to determine the role of gap junctions (GJs) between smooth muscle cells (SMCs) in the sustained HPV development and involvement of arachidonic acid (AA) metabolites in GJ-mediated signaling. Vascular tone was measured in bovine intrapulmonary arteries (BIPAs) using isometric force measurement technique. Expression of contractile proteins was determined by Western blot. AA metabolites in the bath fluid were analyzed by mass spectrometry. Prolonged hypoxia elicited endothelium-independent sustained HPV in BIPAs. Inhibition of GJs by 18β-glycyrrhetinic acid (18β-GA) and heptanol, nonspecific blockers, and Gap-27, a specific blocker, decreased HPV in deendothelized BIPAs. The sustained HPV was not dependent on Ca2+ entry but decreased by removal of Ca2+ and by Rho-kinase inhibition with Y-27632. Furthermore, inhibition of GJs decreased smooth muscle myosin heavy chain (SM-MHC) expression and myosin light chain phosphorylation in BIPAs. Interestingly, inhibition of 15-and 20-hydroxyeicosatetraenoic acid (HETE) synthesis decreased HPV in deendothelized BIPAs. 15-HETE-and 20-HETE-stimulated constriction of BIPAs was inhibited by 18β-GA and Gap-27. Application of 15-HETE and 20-HETE to BIPAs increased SM-MHC expression, which was also suppressed by 18β-GA and by inhibitors of lipoxygenase and cytochrome P450 monooxygenases. More interestingly, 15,20-dihydroxyeicosatetraenoic acid and 20-OH-prostaglandin E2, novel derivatives of 20-HETE, were detected in tissue bath fluid and synthesis of these derivatives was almost completely abolished by 18β-GA. Taken together, our novel findings show that GJs between SMCs are involved in the sustained HPV in BIPAs, and 15-HETE and 20-HETE, through GJs, appear to mediate SM-MHC expression and contribute to the sustained HPV development.
AB - In response to hypoxia, the pulmonary artery normally constricts to maintain optimal ventilation-perfusion matching in the lung, but chronic hypoxia leads to the development of pulmonary hypertension. The mechanisms of sustained hypoxic pulmonary vasoconstriction (HPV) remain unclear. The aim of this study was to determine the role of gap junctions (GJs) between smooth muscle cells (SMCs) in the sustained HPV development and involvement of arachidonic acid (AA) metabolites in GJ-mediated signaling. Vascular tone was measured in bovine intrapulmonary arteries (BIPAs) using isometric force measurement technique. Expression of contractile proteins was determined by Western blot. AA metabolites in the bath fluid were analyzed by mass spectrometry. Prolonged hypoxia elicited endothelium-independent sustained HPV in BIPAs. Inhibition of GJs by 18β-glycyrrhetinic acid (18β-GA) and heptanol, nonspecific blockers, and Gap-27, a specific blocker, decreased HPV in deendothelized BIPAs. The sustained HPV was not dependent on Ca2+ entry but decreased by removal of Ca2+ and by Rho-kinase inhibition with Y-27632. Furthermore, inhibition of GJs decreased smooth muscle myosin heavy chain (SM-MHC) expression and myosin light chain phosphorylation in BIPAs. Interestingly, inhibition of 15-and 20-hydroxyeicosatetraenoic acid (HETE) synthesis decreased HPV in deendothelized BIPAs. 15-HETE-and 20-HETE-stimulated constriction of BIPAs was inhibited by 18β-GA and Gap-27. Application of 15-HETE and 20-HETE to BIPAs increased SM-MHC expression, which was also suppressed by 18β-GA and by inhibitors of lipoxygenase and cytochrome P450 monooxygenases. More interestingly, 15,20-dihydroxyeicosatetraenoic acid and 20-OH-prostaglandin E2, novel derivatives of 20-HETE, were detected in tissue bath fluid and synthesis of these derivatives was almost completely abolished by 18β-GA. Taken together, our novel findings show that GJs between SMCs are involved in the sustained HPV in BIPAs, and 15-HETE and 20-HETE, through GJs, appear to mediate SM-MHC expression and contribute to the sustained HPV development.
KW - 15-hydroxyeicosatetraenoic
KW - Arachidonic acid metabolites
KW - Bovine pulmonary artery
KW - Gap junctions
KW - Hypoxic pulmonary vasoconstriction
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U2 - 10.1152/ajplung.00377.2015
DO - 10.1152/ajplung.00377.2015
M3 - Article
C2 - 26895643
AN - SCOPUS:84984605076
SN - 0363-6135
VL - 310
SP - L772-L783
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 8
ER -