Epac/Rap1 pathway regulates microvascular hyperpermeability induced by PAF in rat mesentery

R. H. Adamson, J. C. Ly, R. K. Sarai, J. F. Lenz, A. Altangerel, D. Drenckhahn, F. E. Curry

Research output: Contribution to journalArticle

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Abstract

Experiments in cultured endothelial cell monolayers demonstrate that increased intracellular cAMP strongly inhibits the acute permeability responses by both protein kinase A (PKA)-dependent and -independent pathways. The contribution of the PKA-independent pathways to the anti-inflammatory mechanisms of cAMP in intact mammalian microvessels has not been systematically investigated. We evaluated the role of the cAMP-dependent activation of the exchange protein activated by cAMP (Epac), a guanine nucleotide exchange factor for the small GTPase Rap1, in rat venular microvessels exposed to the platelet-activating factor (PAF). The cAMP analog 8-pCPT-2′-O-methyl-cAMP (O-Me-cAMP), which stimulates the Epac/Rap1 pathway but has no effect on PKA, significantly attenuated the PAF increase in microvessel permeability as measured by hydraulic conductivity (Lp). We also demonstrated that PAF induced a rearrangement of vascular endothelial (VE)-cadherin seen as numerous lateral spikes and frequent short breaks in the otherwise continuous peripheral immunofluorescent label. Pretreatment with O-Me-cAMP completely prevented the PAF-induced rearrangement of VE-cadherin. We conclude that the action of the Epac/Rap1 pathway to stabilize cell-cell adhesion is a significant component of the activity of cAMP to attenuate an acute increase in vascular permeability. Our results indicate that increased permeability in intact microvessels by acute inflammatory agents such as PAF is the result of the decreased effectiveness of the Epac/Rap1 pathway modulation of cell-cell adhesion.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume294
Issue number3
DOIs
StatePublished - Mar 2008

Fingerprint

Mesentery
Platelet Activating Factor
Microvessels
Cyclic AMP-Dependent Protein Kinases
Permeability
Proteins
Cell Adhesion
Guanine Nucleotide Exchange Factors
Monomeric GTP-Binding Proteins
Capillary Permeability
Cultured Cells
Anti-Inflammatory Agents
Endothelial Cells

Keywords

  • Adenosine 3′,5′-cyclic monophosphate
  • Capillaries
  • Edema
  • Inflammation
  • Vascular permeability

ASJC Scopus subject areas

  • Physiology

Cite this

Epac/Rap1 pathway regulates microvascular hyperpermeability induced by PAF in rat mesentery. / Adamson, R. H.; Ly, J. C.; Sarai, R. K.; Lenz, J. F.; Altangerel, A.; Drenckhahn, D.; Curry, F. E.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 294, No. 3, 03.2008.

Research output: Contribution to journalArticle

Adamson, R. H. ; Ly, J. C. ; Sarai, R. K. ; Lenz, J. F. ; Altangerel, A. ; Drenckhahn, D. ; Curry, F. E. / Epac/Rap1 pathway regulates microvascular hyperpermeability induced by PAF in rat mesentery. In: American Journal of Physiology - Heart and Circulatory Physiology. 2008 ; Vol. 294, No. 3.
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