Diseases of the skeleton have a complex genetic mechanism that reflects the summated effect of multiple genes that are further modified by hormones and the environment of the individual. Murine models that reflect the interaction of genetic and environmental factors will play a major role in interpreting human genetic studies because the genetic background of the mouse can be tightly controlled. One major example is the gene knock out phenotyping program (KOMP). It is designed to perform a systemic examination of KO mice but the proposed skeletal assessment will not be helpful to the bone community because it is limited to a full body digital X-ray and DEXA. This grant will show that it is financially and operationally feasible to append a robust skeletal evaluation program to the ongoing KOMP program. A three-site multi-investigator workflow has been established. Dr. Ackert-Bicknell at The Jackson Laboratory in Maine will receive breeder mice from the KO lines that have been animated, breed, genotyped and examined at that site. She will inject mineralization dyes and harvest the spine, limbs and skull for shipment to UCONN Farmington. At UCONN, Dr. Adams will perform a highly automated microCT of the distal femur, vertebral body and skull to identify KO lines with abnormal skeletal architecture. The selected KO lines will be assessed by Dr. Rowe's staff for dynamic and cellular histomorphometry of trabecular, cortical bone, and cartilage growth plate utilizing a computer automated cryohistological approach that has been adapted for mineralized tissues. Once the digital file set for the histological examination is completed, it is ported the Dr. Shin's group at UCONN Storrs where a custom image analysis program measures the fluorescent signals to compute the histomorphometry in terms that are familiar to the bone biologist. When the analysis is complete, the results, underlying images and relevant background phenotyping will be uploaded to a web-enabled database so that the result is available to the skeletal biology community. A mechanism for external peer review of information to be presented to the public has been established. As the database grows, it will become an invaluable resource by allowing an investigator to query for a physiological phenotype and retrieve all the KO genes that have been mapped to query process at the level of dynamic and cellular histology. The assembled teams have a track record for multidisciplinary and multisite interaction to coordinate daily activities and interpretation of KO data sets. Because of the prior investment in developing the highly automated microCT and histological/image analysis procedures, and the ability to use KO mice directly from a KOMP production line, the cost to perform the screen is probably 1/5 of the cost if performed on an ad hoc basis. This is a one-time opportunity to leverage the existing investment of NIH in the KOMP program to produce information that will be essential for personalized skeletal medicine to have a solid phenotypic foundation.
The promise of genomic medicine is dependent on knowing the function of every human gene. A systematic approach for obtaining this information is underway by the international mouse genetics community, including the NIH. However, the current design does not include a meaningful skeletal examination. This grant will append a skeletal evaluation program alongside the ongoing international effort. It is important to participate in this once in a lifetime research effort to advance the understanding and treatment of osteoporosis and other genetically complex skeletal disease.