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Expression of sphingosine‐1‐phosphate receptor subtypes in rat lung microvessels
Author(s) -
Kandasamy Kathirvel,
Bezavada Lavanya,
Parthasarathi Kaushik
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.lb877
Subject(s) - immunofluorescence , lung , receptor , sphingosine 1 phosphate receptor , pathology , confocal microscopy , receptor expression , biology , chemistry , sphingosine 1 phosphate , medicine , sphingosine , immunology , microbiology and biotechnology , antibody
Sphingosine‐1‐Phosphate (S1P) plays a major role in lung vascular pathophysiology. While S1P receptor subtypes that mediate the signaling in lung vessels are being defined, the expression of the receptors in these vessels remains unclear. Toward this, isolated blood‐perfused rat lung were pump‐perfused at 14 ml/min with autologous blood. The pulmonary artery, left atrial, and airway pressures were maintained at 10, 3, and 5 cmH 2 O, respectively. Through a microcatheter inserted via the left atrial cannula, we cleared blood cells from a small lung region and determined expression of S1P receptor 1–4 in microvessels by indirect in situ immunofluorescence. In two lungs for each receptor, we captured images of surface microvessels using a confocal microscope and quantified fluorescence intensity along the wall of the vessels. S1P4 immunofluorescence in venules and capillaries was 76.7±3.7 (n=11) and 27.7±1.8 (n=36), respectively. Immunofluorescence of S1P1, S1P2, and S1P3 in venules was 33.9±3.4 (n=15), 27.0±5.1 (n=10), and 31±2.9 (n=9), respectively, and in capillaries was 15.4±0.7 (n=50),11.8±0.8 (n=50) and 11.4±1 (n=43), respectively. These data revealed that S1P4 immunofluorescence was higher compared to other subtypes (p< 0.001). Thus, we show for the first time that in lung venules and capillaries (1) S1P receptors 1–4 are expressed, and (2) S1P4 may be the predominant receptor subtype. NIH HL75503