To produce useful analytical information from such small samples, the researchers employed an innovative combination of laser capture microscopy with their newly developed liquid chromatography separation methods, followed by gel electrophoresis and mass spectrometry analysis. |
A
new technique developed at Rensselaer Polytechnic Institute allows
researchers to collect large amounts of biochemical information from
nanoscale bone samples.
Along
with adding important new insights into the fight against osteoporosis,
this innovation opens up an entirely new proteomics-based approach to
analyzing bone quality. It could even aid the archeological and forensic
study of human skeletons.
“We’re
able to take very small, nanoscale-sized bone samples, and determine
the protein signatures of the bone,” said Deepak Vashishth, head of the
Department of Biomedical Engineering at Rensselaer, who led the study.
“This is a relatively quick, easy way for us to determine the history of
the bone – how and when it formed – as well as the quality of the bone,
and its likelihood to fracture.”
Results
of the study, titled “Biochemical Characterization of Major Bone-Matrix
Proteins Using Nanoscale-Size Bone Samples and Proteomics Methodology,”
were released online in late May by the journal Molecular &
Cellular Proteomics. The journal, published by the American Society for
Biochemistry and Molecular Biology, will also feature the paper in an
upcoming print edition.
The
research, funded by the U.S. National Institutes of Health, was
conducted in the laboratories of the Center for Biotechnology and
Interdisciplinary Studies at Rensselaer.
Bones
are primarily composed of mineral, with the remaining amount comprised
of organic material. The vast majority of the organic material is
collagen. The remaining non-collagenous organic material is a mixture of
other proteins, which form an interlinked matrix. The quality of this
matrix varies greatly with age, nutrition, and disease. Vashishth and
his research group investigate this bone matrix to determine how the
interaction and modification of individual proteins impact the
development, structure, and strength of the overall bone.
In
this study, they paired laser-capture microscopy with several other
techniques to create an entirely new method for analyzing bone matrix.
The analysis yields data about the concentration of different proteins
in the bone matrix, which in turn leads to key information about the
bone – such as when it was formed, how it has been modified, and if it
is more or less prone to fracture.
Vashishth
said this is an important step toward augmenting current osteoporosis
diagnosis techniques, which measure bone loss and the quantity of bone
present, with new, minimally invasive, proteomics-driven techniques for
assessing the quality of the bone.
The
young field of proteomics focuses on the structure and function of
proteins, and is ripe for innovation, Vashishth said. The term
“proteomics” echoes the word genomics, the study of genes. Proteomics
seeks to decode the human proteome by documenting the structure,
function, and interactions of proteins.
The new approach required new analytical techniques and sophisticated data analysis. |
“This
is kind of a new area, because bone fracture has always been looked at
from a bone calcium perspective, a mineral perspective, and current
osteoporosis treatment methods are all geared toward that,” he said. “In
osteoporosis, very little attention has been paid to bone proteins.
That’s why we’re very excited about our new proteomics-based method to
read a bone’s protein signature, and assess the quality of the bone. I
think it opens up a new avenue for approaching and studying
osteoporosis.”
Like
all tissues in the human body, bones regenerate themselves over time.
Bones regenerate much slower than other tissues, however, and the
skeleton takes about 10 years to gradually replace itself with new
tissue. Different parts of a bone regenerate at different rates, meaning
some areas of a bone may be older and more susceptible to fracture,
while other areas of the same bone are newer and sturdier. Older and
younger parts of a bone have different protein signatures and react
differently to medical treatments. Vashishth said his new method is an
easy way to help differentiate between different aged areas of bone,
determine their quality, and forecast their susceptibility to fracture.
Finally,
along with pushing forward the emerging field of bone proteomics and
opening up new possibilities for studying and treating osteoporosis,
Vashishth’s findings could prove useful to researchers in other areas
who deal with bone. Forensics, biology, anthropology, archaeology, and
other areas where bone samples are truly rare, small, and precious would
likely find it useful to analyze bone protein signatures with minimal
damage to the bone sample, he said. This protein signature information
could offer new insight into how bones were formed, along with the
nutrition and diet of those individuals.
Co-authors
of the study are Wilfredo Colon, professor in the Rensselaer Department
of Chemistry and Biological Chemistry; as well as postdoctoral
researcher Grazyna Sroga and doctoral student Lamya Karim, both in the
Rensselaer Department of Biomedical Engineering.
