title: Histamine activates p38 MAP kinase and alters local lamellipodia dynamics, reducing endothelial barrier integrity and eliciting central movement of actin fibers.
abstract: The role of the actin cytoskeleton in endothelial barrier function has been debated for nearly four decades. Our previous investigation revealed spontaneous local lamellipodia in confluent endothelial monolayers that appear to increase overlap at intercellular junctions. We tested the hypothesis that the barrier-disrupting agent histamine would reduce local lamellipodia protrusions and investigated the potential involvement of p38 mitogen-activated protein (MAP) kinase activation and actin stress fiber formation. Confluent monolayers of human umbilical vein endothelial cells (HUVEC) expressing green fluorescent protein-actin were studied using time-lapse fluorescence microscopy. The protrusion and withdrawal characteristics of local lamellipodia were assessed before and after addition of histamine. Changes in barrier function were determined using electrical cell-substrate impedance sensing. Histamine initially decreased barrier function, lamellipodia protrusion frequency, and lamellipodia protrusion distance. A longer time for lamellipodia withdrawal and reduced withdrawal distance and velocity accompanied barrier recovery. After barrier recovery, a significant number of cortical fibers migrated centrally, eventually resembling actin stress fibers. The p38 MAP kinase inhibitor SB203580 attenuated the histamine-induced decreases in barrier function and lamellipodia protrusion frequency. SB203580 also inhibited the histamine-induced decreases in withdrawal distance and velocity, and the subsequent actin fiber migration. These data suggest that histamine can reduce local lamellipodia protrusion activity through activation of p38 MAP kinase. The findings also suggest that local lamellipodia have a role in maintaining endothelial barrier integrity. Furthermore, we provide evidence that actin stress fiber formation may be a reaction to, rather than a cause of, reduced endothelial barrier integrity.
authors.affiliation: Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and.
authors.forename: Shaquria P
authors.initials: SP
authors.lastname: Adderley
authors.affiliation: Biology Unit, Department of Natural Sciences, Southern University at New Orleans, New Orleans, Louisiana.
authors.forename: Curtis
authors.initials: C
authors.lastname: Lawrence
authors.affiliation: Biology Unit, Department of Natural Sciences, Southern University at New Orleans, New Orleans, Louisiana.
authors.forename: Eyong
authors.initials: E
authors.lastname: Madonia
authors.affiliation: Biology Unit, Department of Natural Sciences, Southern University at New Orleans, New Orleans, Louisiana.
authors.forename: Joseph O
authors.initials: JO
authors.lastname: Olubadewo
authors.affiliation: Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and jbreslin@health.usf.edu.
authors.forename: Jerome W
authors.initials: JW
authors.lastname: Breslin
mesh_terms: D002465:Cell Movement / Q000187:drug effects*; D002478:Cells, Cultured; D017097:Electric Impedance; D004789:Enzyme Activation; D006632:Histamine / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D010539:Permeability; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011554:Pseudopodia / Q000187:drug effects* / Q000201:enzymology; D015398:Signal Transduction / Q000187:drug effects; D022502:Stress Fibers / Q000187:drug effects* / Q000201:enzymology; D013997:Time Factors; D059008:Time-Lapse Imaging; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D047428:Protein Kinase Inhibitors; D006632:Histamine; D048051:p38 Mitogen-Activated Protein Kinases
keywords: actin cables; endothelial permeability; inflammation; lamellipodia; p38 MAPK