Microtubules in lung endothelial cell barrier regulation

Project: Research project

Project Details

Description

DESCRIPTION (Applicant's Abstract): Disturbances in endothelial cell (EC)
barrier regulation is a hallmark of lung inflammation, angiogenesis and cancer,
and is critically dependent upon rearrangements in the cytoskeleton
(microfilaments and microtubules). We have previously shown the involvement of
microfilaments in actomyosin-driven contraction in specific models of lung EC
permeability. For example, edemagenic agents such as thrombin increase the
level of phosphorylation of myosin "regulatory" light chain (MLC20), which is
tightly linked to stress fiber formation, gap formation and barrier
dysfunction. In contrast, cAMP elevation has a barrier protective effect and
significantly attenuates thrombin-induced MLC phosphorylation and barrier
dysfunction. Although information is limited as how to changes in microtubule
network regulate EC contractility, careful temporal analysis of the MLC
phosphorylation status in cultured EC reveals that disruption of the cellular
microtubule structure with the clinically relevant agents such as vinblastine
significantly increases MLC phosphorylation, decreases electrical resistance of
EC monolayer and increases transendothelial neutrophil migration reflecting EC
barrier dysfunction. Stabilization of microtubule structure by paclitaxel
completely abolishes these effects and significantly attenuates
thrombin-induced EC stress fiber formation. In addition, microtubule disruption
activates MAP kinase (p38 and ERKs) pathway in endothelium, which also
potentially can be involved in MLC-independent EC contractility via
phosphorylation of key cytoskeletal proteins, like caldesmon and HSP-27. In
this proposal, we will explore the role of MLC-dependent and MLC-independent
mechanisms in the regulation of EC contraction and barrier dysfunction, induced
by microtubule disruption in both macro- and microvascular endothelium. In SA 1
we will identify mechanisms leading of microtubule-mediated increases in EC MLC
phosphorylation by examining how MLC-specific kinase and phosphatase activities
are affected by microtubule alterations. In SA 2 we will identify
MLC-independent pathways involved in microtubule-mediated EC contractility and
barrier dysfunction and examine the effect of MAPK activities on cytoskeletal
protein phosphorylation, cytoskeletal rearrangement and barrier function. In SA
3 we will examine the ole of cAMP-mediated barrier protection on EC barrier
failure, induced by microtubule disruption. These studies will provide an
understanding of novel signaling pathways involved in lung EC barrier
regulation and promise new directions and targets for treatment of lung
disorders.
StatusFinished
Effective start/end date4/1/016/30/11

Funding

  • National Heart, Lung, and Blood Institute: $356,843.00
  • National Heart, Lung, and Blood Institute: $383,750.00
  • National Heart, Lung, and Blood Institute: $327,000.00
  • National Heart, Lung, and Blood Institute: $356,843.00
  • National Heart, Lung, and Blood Institute: $356,843.00
  • National Heart, Lung, and Blood Institute: $163,500.00
  • National Heart, Lung, and Blood Institute: $352,250.00
  • National Heart, Lung, and Blood Institute: $163,500.00

ASJC

  • Medicine(all)

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