Aims: Our overall objective is to understand the regulation of pro-inflammatory responses that develop in a spatially distributed, segment specific manner in the intact lung capillaries. Here, we will determine the role of mitochondrial mechanisms in regulation of leukocyte margination in arteriolar, septal and venular capillaries.
The specific aims are to quantify for the first time capillary segment specific, regulation of endothelial (EC) mitochondrial (Ca2+mit) and cytosolic Ca2+cyt) (Specific Aim 1), generation of EC mitochondrial reactive oxygen species (ROS) (Specific Aim 2), and mitochondria-mediated leukocyte margination (Specific Aim 3). The new hypotheses to be tested are that mitochondrial distribution and the induction of mitochondrial mechanisms are vascular segment specific, and that differences in the extent to which mitochondrial mechanisms are invoked determine differences in pro-inflammatory responses in the various vascular segment of the lung. Procedures: 1) Morphometric measurements. Intravital imaging of mitochondrial and endosomal stores (ER) will be conducted in capillaries of the isolated, blood-perfused rat lung, using both conventional and confocal microscopy. 2) Ca2+ quantification, Ca2+mit, Ca2+cyt, and ER Ca2+ changes will be determined using flurophores that target the appropriate compartment. 3) ROS quantification. EC ROS production will be determined using fluorometric imaging of the ROS indicator dichloro fluorescin using our reported protocols. In one set of experiments we will test the hypotheses in a mouse lacking components of NADPH-oxidase to determine the role on non-mitochondiral ROS production. 4) Immunofluorescence imaging. Expression of P-selectin in capillaries will be determined using indirect in situ immunofluorescence imaging. 5) Leukocyte margination. Leukocyte margination will be determined using confocal and conventional microscopy using leukocytes labeled with, rhodamine 6G. 6) Ca2+ increase. EC Ca2+ will be increased by a) infusion of agonists and b) in situ photo-excited intracellular uncaging. Responses will be determined in terms of mitochondrial mechanisms that increase ROS production and leukocyte margination. Significance: This proposal addresses a new understanding of pro-inflammatory responses in different capillary segments. These segment-specific responses, which determine the preferential pathway for leukocyte margination during inflammation, are not adequately understood. It is important to understand the role of mitochondria, as mitochondrial mechanisms and mitochondrial ROS may critically regulate leukocyte margination and hence, lung injury. Mitochondrial ROS may also be involved in signaling gene transcription and consequently, lung remodeling. If the preliminary data hold, then this research will prove for the first time that mitochondrial mechanisms regulate vascular segment specific pro-inflammatory responses.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL075503-02
Application #
6803068
Study Section
Special Emphasis Panel (ZHL1-CSR-N (S1))
Program Officer
Denholm, Elizabeth M
Project Start
2003-09-22
Project End
2007-07-31
Budget Start
2004-08-01
Budget End
2005-07-31
Support Year
2
Fiscal Year
2004
Total Cost
$403,500
Indirect Cost
Name
St. Luke's-Roosevelt Institute for Health Sciences
Department
Type
DUNS #
623216371
City
New York
State
NY
Country
United States
Zip Code
10019
Escue, Rachel; Kandasamy, Kathirvel; Parthasarathi, Kaushik (2017) Thrombin Induces Inositol Trisphosphate-Mediated Spatially Extensive Responses in Lung Microvessels. Am J Pathol 187:921-935
Kandasamy, Kathirvel; Escue, Rachel; Manna, Jayeeta et al. (2015) Changes in endothelial connexin 43 expression inversely correlate with microvessel permeability and VE-cadherin expression in endotoxin-challenged lungs. Am J Physiol Lung Cell Mol Physiol 309:L584-92
Kandasamy, Kathirvel; Parthasarathi, Kaushik (2014) Quantifying single microvessel permeability in isolated blood-perfused rat lung preparation. J Vis Exp :e51552
Kandasamy, Kathirvel; Bezavada, Lavanya; Escue, Rachel B et al. (2013) Lipopolysaccharide induces endoplasmic store Ca2+-dependent inflammatory responses in lung microvessels. PLoS One 8:e63465
Makena, Patrudu S; Gorantla, Vijay K; Ghosh, Manik C et al. (2012) Deletion of apoptosis signal-regulating kinase-1 prevents ventilator-induced lung injury in mice. Am J Respir Cell Mol Biol 46:461-9
Parthasarathi, Kaushik (2012) Endothelial connexin43 mediates acid-induced increases in pulmonary microvascular permeability. Am J Physiol Lung Cell Mol Physiol 303:L33-42
Kandasamy, Kathirvel; Sahu, Geetaram; Parthasarathi, Kaushik (2012) Real-time imaging reveals endothelium-mediated leukocyte retention in LPS-treated lung microvessels. Microvasc Res 83:323-31
Makena, Patrudu S; Gorantla, Vijay K; Ghosh, Manik C et al. (2011) Lung injury caused by high tidal volume mechanical ventilation and hyperoxia is dependent on oxidant-mediated c-Jun NH2-terminal kinase activation. J Appl Physiol (1985) 111:1467-76
Parthasarathi, Kaushik; Bhattacharya, Jahar (2011) Localized acid instillation by a wedged-catheter method reveals a role for vascular gap junctions in spatial expansion of acid injury. Anat Rec (Hoboken) 294:1585-91
Makena, Patrudu S; Luellen, Charlean L; Balazs, Louisa et al. (2010) Preexposure to hyperoxia causes increased lung injury and epithelial apoptosis in mice ventilated with high tidal volumes. Am J Physiol Lung Cell Mol Physiol 299:L711-9

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