Event
Bioengineering Seminar Series: Adam Hsieh
Friday, February 7, 2014
9:00 a.m.-10:00 a.m.
Pepco Room (1105), Jeong H. Kim Engineering Building
Professor Ian White
ianwhite@umd.edu
Adam Hsieh
Associate Professor and Associate Chair
Director of Undergraduate Studies
Fischell Department of Bioengineering
University of Maryland
Adjunct Associate Professor
Department of Orthopaedics
University of Maryland, Baltimore
Cellular Mechanobiology in 4-D – The Role of Space-Time in Intervertebral Disc and Stem Cells
The intervertebral disc (IVD) plays a central role in spinal function, serving as a unique joint that cushions loads and simultaneously enables flexibility and stabilizes motion segments. In healthy discs, the chief mechanism for fulfilling this role is through pressurization of the nucleus pulposus (NP), which consequently places the annulus fibrosus (AF) in tension. Cellular and biochemical changes that occur during aging compromise NP function and lead to greater susceptibility to degenerative disc disease (DDD). Although it is believed that spinal loading has at least a contributory, if not pivotal, influence on aging and disease, the precise role of mechanical stress is not yet clear.
Our laboratory has been focused on developing strategies toward more effective preventative and therapeutic interventions against DDD. One area of recent focus has been in investigating how the timing of daily spinal loads might influence IVD mechanobiology. Using a combination of imaging, computational, and experimental techniques, we demonstrate that the IVD exhibits profound spatial and temporal variations in micromechanical environment, at magnitudes known to be significant in regulating cell function. Based on these findings, we have been working to develop a framework that can serve as a guide toward non-invasive strategies to promote spine health.
A second area has been in elucidating the role of the developing pericellular matrix (PCM) in human mesenchymal stem cells (hMSCs) undergoing chondrogenic differentiation. The potential for stem cell-based therapies against DDD to succeed requires an understanding of how cells will respond to the in situ micromechanical environment. For cells stimulated toward a chondrocyte-like phenotype, the PCM is central to cellular mechanotransduction. Using genetic engineering approaches, we dissect the contributions of specific PCM proteins in cell mechanics and mechanobiology. Our results suggest that the biophysical regulation of hMSCs relies on both time-dependent PCM accumulation and PCM composition.
