Disruption of the endothelial cell (EC) barrier is a prominent feature of acute lung injury (ALI). EC permeability is regulated by a balance between contractile and tethering forces and is dependent on the functional coordination of interrelated elements of the cytoskeleton, namely microfilaments (MF) and microtubules (MT). Our novel data indicate that MT remodeling is directly involved in thrombin-induced EC barrier compromise. Similar to thrombin, lipopolysaccharide (LPS) induces partial dissolution of the MT network, which correlates with an increase in EC permeability in vitro. Our novel preliminary data demonstrated that single intravenous dose of MT stabilizer, taxol, produced significant reductions in multiple indices of LPS-induced inflammatory lung injury suggesting the involvement of MT remodeling in sepsis-induced ALI in vivo. Thrombin-induced signaling involves activation of heterotrimeric G-proteins, G12 and G13. We have demonstrated that depletion of subunits of these proteins attenuates thrombin-induced EC permeability, whereas their overexpression led to MT disassembly and massive stress fiber formation, indicative of contraction. Inhibition of Rho and p38 MARK pathways attenuates the effect of thrombin on MT structure suggesting the involvement of these pathways in MT remodeling. Our data indicate that significant pools of Rho kinase and p38 MARK are tightly associated with MT. Thrombin induces phosphorylation of several MT- and MF-associated regulatory proteins, including caldesmon (CaD), HSP-27 and tau, which are potentially responsible for thrombin-induced changes in MT and MF structure. We hypothesize that thrombin-induced activation of G12 and G13 leads to activation of Rho and p38 MARK signaling, phosphorylation of cytoskeletal regulatory proteins, coordinated MT and MF remodeling and finally to barrier compromise.
Specific Aim 1 will define the role of G12 and G13 in thrombin-induced MT disassembly and EC permeability.
Specific Aim 2 will examine the role of MT- and MF-binding regulatory proteins, tau, CaD and HSP-27, in thrombin-induced MT remodeling and barrier failure.
Specific Aim 3 will examine the role of MT remodeling in sepsis-induced lung injury using a murine model of ALI. These studies will examine basic molecular mechanisms by which MT are involved in EC barrier regulation and promise new directions and targets for treatment of lung disorders. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL067307-05A2
Application #
7146926
Study Section
Lung Injury, Repair, and Remodeling Study Section (LIRR)
Program Officer
Denholm, Elizabeth M
Project Start
2001-04-01
Project End
2007-01-31
Budget Start
2006-07-01
Budget End
2007-01-31
Support Year
5
Fiscal Year
2006
Total Cost
$383,750
Indirect Cost
Name
University of Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Alieva, Irina B; Zemskov, Evgeny A; Smurova, Ksenija M et al. (2013) The leading role of microtubules in endothelial barrier dysfunction: disassembly of peripheral microtubules leaves behind the cytoskeletal reorganization. J Cell Biochem 114:2258-72
Kása, Anita; Czikora, István; Verin, Alexander D et al. (2013) Protein phosphatase 2A activity is required for functional adherent junctions in endothelial cells. Microvasc Res 89:86-94
Kim, Kyung-mi; Adyshev, Djanybek M; Kása, Anita et al. (2013) Putative protein partners for the human CPI-17 protein revealed by bacterial two-hybrid screening. Microvasc Res 88:19-24
Kim, Kyung-Mi; Csortos, Csilla; Czikora, Istvan et al. (2012) Molecular characterization of myosin phosphatase in endothelium. J Cell Physiol 227:1701-8
Gorshkov, Boris A; Zemskova, Marina A; Verin, Alexander D et al. (2012) Taxol alleviates 2-methoxyestradiol-induced endothelial permeability. Vascul Pharmacol 56:56-63
Lucas, Rudolf; Yang, Guang; Gorshkov, Boris A et al. (2012) Protein kinase C-? and arginase I mediate pneumolysin-induced pulmonary endothelial hyperpermeability. Am J Respir Cell Mol Biol 47:445-53
Antonov, Alexander S; Antonova, Galina N; Fujii, Makiko et al. (2012) Regulation of endothelial barrier function by TGF-ýý type I receptor ALK5: potential role of contractile mechanisms and heat shock protein 90. J Cell Physiol 227:759-71
Poirier, Christophe; Berdyshev, Evgeny V; Dimitropoulou, Christiana et al. (2012) Neutral sphingomyelinase 2 deficiency is associated with lung anomalies similar to emphysema. Mamm Genome 23:758-63
Poirier, Christophe; Gorshkov, Boris A; Zemskova, Marina A et al. (2011) TIMAP protects endothelial barrier from LPS-induced vascular leakage and is down-regulated by LPS. Respir Physiol Neurobiol 179:334-7
Bogatcheva, Natalia V; Zemskova, Marina A; Gorshkov, Boris A et al. (2011) Ezrin, radixin, and moesin are phosphorylated in response to 2-methoxyestradiol and modulate endothelial hyperpermeability. Am J Respir Cell Mol Biol 45:1185-94

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