Severe sepsis is a common, expensive, and frequently fatal condition which is the leading cause of death in the ICU in the United States. It s especially common in the elderly and is likely to increase substantially as the U.S. population ages. Sepsis develops as a result of the host response to infection, and often presents as systemic inflammatory response syndrome (SIRS), but may also develop into multiple organ failure (MOF) with vascular endothelial inflammation and lung dysfunction among major fatal complications in critically ill patients. Typically, 50% of all sepsis cases start as an infection n the lungs. In the last decade, gram-positive bacteria, most commonly staphylococci, are thought to cause more than 50% of cases of sepsis. Activated vascular endothelium plays a key role in propagation of inflammation by increasing the extravasation of inflammatory cells, cytokines and chemokines. Endothelial inflammation and barrier compromise in septic conditions may lead to multiple organ dysfunction and disseminated intravascular coagulation. Although the essential role of endothelium in these events is well recognized, precise mechanisms modulating inflammatory activation of vascular endothelium in septic conditions are poorly understood. Our previous studies defined the role of microtubule dynamics in the disruption of lung endothelial barrier and vascular leak caused by vasoactive growth factors and agonists. However, the involvement of microtubule-dependent mechanisms in endothelial inflammatory processes awaits further investigation. The central hypothesis supported by our novel preliminary data which will be tested in this application is that activation of microtubule-specific histone deacetylase HDAC6 in endothelial cells challenged with Staphylococcus aureus causes microtubule destabilization and reduction in anti-inflammatory activity of microtubule-associated Suppressor Of Cytokine Signaling, SOCS3. As a result of SOCS3 inactivation, augmented Jak2/STAT3 signaling will unleash cytokine release and exacerbate ongoing inflammatory reaction to bacterial pathogen causing collateral damage of the host organism. We speculate that stabilization of the microtubules via inhibition of HDAC6 leading to preservation of SOCS3 activity may protect against excessive septic inflammation.
Aim -1 will characterize the changes in endothelial microtubule dynamics and their regulation by HDAC6 in the models of lung septic inflammation;
AIm -2 will examine how altered microtubule dynamics modulate SOCS3-dependent inflammatory signaling induced by bacterial pathogens;
and Aim -3 will study the role of microtubule-associated signaling in the modulation of inflammatory response in vivo. We believe that this study will identify new targets for therapies designed to blunt sepsis-activated pathologic signaling circuits and may result in a breakthrough in current practices of sepsis treatment.

Public Health Relevance

Sepsis remains a major cause of morbidity and mortality, however development of effective therapies for sepsis treatment represents a major challenge. This study will focus on the investigation of microtubule- associated molecular mechanisms promoting reduction of inflammatory signaling caused by Gram-positive infection. The results of this project will uncover a novel mechanisms involved in the regulation of inflammatory response and may lead to discovery of a new group of pharmacological molecules for the treatment of sepsis and other diseases associated with increased vascular leakage and inflammation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM114171-04
Application #
9275864
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Dunsmore, Sarah
Project Start
2015-08-15
Project End
2019-05-31
Budget Start
2017-06-01
Budget End
2018-05-31
Support Year
4
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Maryland Baltimore
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Oskolkova, Olga; Sarich, Nicolene; Tian, Yufeng et al. (2018) Incorporation of iloprost in phospholipase-resistant phospholipid scaffold enhances its barrier protective effects on pulmonary endothelium. Sci Rep 8:879
Oskolkova, Olga; Gawlak, Grzegorz; Tian, Yufeng et al. (2017) Prostaglandin E receptor-4 receptor mediates endothelial barrier-enhancing and anti-inflammatory effects of oxidized phospholipids. FASEB J 31:4187-4202
Ke, Yunbo; Zebda, Noureddine; Oskolkova, Olga et al. (2017) Anti-Inflammatory Effects of OxPAPC Involve Endothelial Cell-Mediated Generation of LXA4. Circ Res 121:244-257
Ohmura, Tomomi; Tian, Yufeng; Sarich, Nicolene et al. (2017) Regulation of lung endothelial permeability and inflammatory responses by prostaglandin A2: role of EP4 receptor. Mol Biol Cell 28:1622-1635
Tian, Xinyong; Ohmura, Tomomi; Shah, Alok S et al. (2017) Role of End Binding Protein-1 in endothelial permeability response to barrier-disruptive and barrier-enhancing agonists. Cell Signal 29:1-11
Ke, Yunbo; Oskolkova, Olga V; Sarich, Nicolene et al. (2017) Effects of prostaglandin lipid mediators on agonist-induced lung endothelial permeability and inflammation. Am J Physiol Lung Cell Mol Physiol 313:L710-L721
Huang, Ru-Ting; Wu, David; Meliton, Angelo et al. (2017) Experimental Lung Injury Reduces Krüppel-like Factor 2 to Increase Endothelial Permeability via Regulation of RAPGEF3-Rac1 Signaling. Am J Respir Crit Care Med 195:639-651
Birukova, Anna A; Shah, Alok S; Tian, Yufeng et al. (2016) Selective Role of Vinculin in Contractile Mechanisms of Endothelial Permeability. Am J Respir Cell Mol Biol 55:476-486
Tian, Yufeng; Gawlak, Grzegorz; O'Donnell 3rd, James J et al. (2016) Modulation of Endothelial Inflammation by Low and High Magnitude Cyclic Stretch. PLoS One 11:e0153387
Gawlak, Grzegorz; Son, Sophia; Tian, Yufeng et al. (2016) Chronic high-magnitude cyclic stretch stimulates EC inflammatory response via VEGF receptor 2-dependent mechanism. Am J Physiol Lung Cell Mol Physiol 310:L1062-70

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