
Ph.D. Mechanical Engineering, 1998
The City University of New York, New
York, NY
Associate Professor of Bioengineering
228 Hallowell Building
University Park, PA 16802-6804
Tel: (814) 865-8086
Fax: (814) 863-0490
Email: pjbbio@engr.psu.edu
Research and Teaching Interests
The
research in Dr. Butler’s Cellular Mechanobiology Laboratory focuses on the fundamental
molecular mechanisms by which vascular endothelial cells sense
the forces from flowing blood and transduce this mechanical
information into adjustments of cell and tissue biology. For
example, Dr.
Butler has found that the frictional force of blood flow, shear
stress, results in a dilation of small arterioles and that
the magnitude of this dilation depends on the rate of change
of the
shear stress. It is believed that arterioles use this rate-sensitivity
to continually adjust blood flow to organs such as skeletal
muscles during exercise. Shear stress is also important in
the development
of pathologies such as atherosclerosis and hypertension. Depending
on spatial and temporal characteristics of the shear stress,
endothelial cells adjust the expression of genes to adapt to
their flow environment.
A
major focus of Dr. Butler’s research is to elucidate the
fundamental molecular mechanisms of mechanotransduction. To accomplish
this goal, Dr. Butler, along with his students, have designed
and built a confocal molecular dynamics microscope (CMDM) which
allows
nanosecond, and nanometer scale investigations of molecular dynamics
in 3-dimensions in intact cells. This system uses time-resolved
fluorescence microscopy to investigate the fluorescence lifetimes,
rotations, diffusions, and transport of molecules at the cell
surface, in the membrane, and in the cell cytoplasm.
Dr. Butler also co-Directs the Biomaterials
and Bionanotechnology Summer
Institute which
provides summer research and educational opportunities for undergraduate and
first year graduate students.
Representative Publications
Li,S., Butler, P., Wang,Y., Hu,Y., Han, D.C., Usami,S., Guan,J.L., and Chien,S. (2002). The
role of the dynamics of focal adhesion kinase in the mechanotaxis of
endothelial cells. Proc. Natl. Acad. Sci.
U. S. A 99, 3546-3551. Abstract Full
Text.
Butler,
P.J., Tsou,T.C., Li,J.Y., Usami,S.,
and Chien,S. (2001). Rate
sensitivity of shear-induced changes in the lateral diffusion
of endothelial cell membrane lipids: a role for membrane
perturbation in shear-induced MAPK activation. FASEB
J. 16(2), 216-8. Abstract Full Text
Butler ,P.J., Norwich ,G., Weinbaum,S., and Chien,S.
(2001). Shear stress induces a time- and position-dependent
increase in endothelial cell membrane fluidity. Am.
J. Physiol Cell Physiol 280, C962-C969. Abstract Full Text
Butler ,P.J., Weinbaum,S., Chien,S., and Lemons,D.E.
(2000). Endothelium-dependent, shear-induced vasodilation
is rate-sensitive. Microcirculation. 7, 53-65. Abstract Full text
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