The Journal of Neuroscience, December 15, 2002, 22(24):10772-10780
4 Integrins and Vascular Cell Adhesion Molecule-1 Play a Role
in Sympathetic Innervation of the Heart
Kevin L.
Wingerd1,
Nichol L.
Goodman1,
Jason
W.
Tresser1,
Matthew M.
Smail1,
Sergiu T.
Leu1,
Steven J.
Rohan1,
Jan L.
Pring1,
David Y.
Jackson2, and
Dennis O.
Clegg1
1 Neuroscience Research Institute and Department of
Molecular, Cellular and Developmental Biology, University of
California, Santa Barbara, Santa Barbara, California 93106, and
2 Genentech Inc., Department of Bioorganic Chemistry, South
San Francisco, California 94080
Sympathetic neurons innervate the heart early in postnatal
development, an event that is crucial for proper modulation of blood
pressure and cardiac function. However, the axon guidance cues that
direct sympathetic neurons to the heart, and the neuronal receptors
that recognize those cues, are poorly understood. Here we present
evidence that interactions between the
4
1 integrin on sympathetic
neurons and vascular cell adhesion molecule-1 (VCAM-1) in the heart
plays a role in cardiac innervation.
The
4 subunit was detected on postnatal rat superior cervical
ganglion (SCG) neurons in culture and in cryosections of SCG and heart.
VCAM-1 immunoreactivity was detected on cardiac myocytes that associate
with invading sympathetic neurons. Purified recombinant soluble VCAM-1
(rsVCAM-1) stimulated SCG neurite outgrowth at levels comparable with
laminin 2/4 and fibronectin (Fn), and outgrowth on rs-VCAM-1 and
Fn was blocked by antibodies specific for the
4 and
1 integrin
subunits. Intrathoracic injection of function-blocking antibodies to
4 and VCAM-1, as well as a small molecule inhibitor of
4
integrins, significantly reduced sympathetic innervation of the heart.
These results indicate that the interaction between
4 integrin and
VCAM-1 is important for sympathetic innervation of the heart.
Key words:
integrins; vascular cell adhesion molecule-1; sympathetic
neurons; heart; neurite outgrowth; neural development
Copyright © 2002 Society for Neuroscience 0270-6474/02/222410772-09$05.00/0