# Inactivation Mechanisms of Microvascular Hyperpermeability

> **NIH NIH R01** · RBHS-NEW JERSEY MEDICAL SCHOOL · 2022 · $637,363

## Abstract

PROJECT SUMMARY/ABSTRACT
Vascular hyperpermeability is a hallmark of inflammation. Current therapy interferes with mechanisms involved
in onset of hyperpermeability. We will focus on mechanisms that terminate hyperpermeability because
negative effects of hyperpermeability are due to its persistence beyond the time required for preserving organ
function. We will elucidate mechanisms that actively terminate hyperpermeability. This work is based on a)
current knowledge of protein traffic mechanisms, b) the fundamental role of VASP (vasodilator stimulated
phosphoprotein) in cell adhesion and endothelial barrier properties, c) our demonstration that eNOS
translocation to cytosol is necessary for onset of hyperpermeability, d) our preliminary data demonstrating that
selective stimulation of Epac1 (exchange protein activated by cAMP) returns eNOS to the cell membrane, and
e) our preliminary data showing that VASP is required for returning eNOS to the plasma membrane. We will
test the central hypothesis that the agonist signaling that leads to hyperpermeability initiates a delayed
increase in [cAMP], which causes VASP-assisted translocation of eNOS and Epac1 to the cell
membrane and triggers inactivation of hyperpermeability. This novel hypothesis, in which barrier
restoration is an active process operating via signaling mechanisms distinct from those that cause
hyperpermeability, will be tested through two Specific Aims (SA). In each Specific Aim, we will stimulate eNOS
translocation to the cell membrane with 8-cPT-2-O-Me-cAMP, a selective activator of Epac1, and will measure
permeability as an end-point. SA1: To test whether the activity of cytoplasmic eNOS during hyperpermeability
causes an increase in cAMP that leads to inactivation of hyperpermeability. We will assess inactivation of
hyperpermeability and measure [cAMP] as a function of NO and time under conditions that anchor eNOS to
cytosol or plasma membrane and protocols that stimulate or inhibit [cAMP] in vivo and in vitro. SA2: To
determine the role of phosphorylated VASP as a molecular partner in eNOS and Epac1 translocation to cell
membrane. In wild-type endothelial cells (EC) and in EC VASP-KO cells, we will explore the relationships
among [NO], VASP phosphorylation, eNOS translocation and inactivation of hyperpermeability. We will
stimulate eNOS translocation to cell membrane with 8-cPT-2-O-Me-cAMP in vivo and in vitro. We will assess
the relationship between VASP phosphorylation and co-localization of eNOS and Epac1 using proximity
ligation assay (PLA). The elucidation of the processes that inactivate and terminate hyperpermeability will be
novel advances in knowledge of regulatory mechanisms of microvascular permeability and will provide the
basis for developing new therapies for treating vascular inflammation.

## Key facts

- **NIH application ID:** 10335153
- **Project number:** 5R01HL146539-03
- **Recipient organization:** RBHS-NEW JERSEY MEDICAL SCHOOL
- **Principal Investigator:** Walter N. Duran
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $637,363
- **Award type:** 5
- **Project period:** 2020-02-04 → 2024-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10335153

## Citation

> US National Institutes of Health, RePORTER application 10335153, Inactivation Mechanisms of Microvascular Hyperpermeability (5R01HL146539-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10335153. Licensed CC0.

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