The use of solid scaffolds that provide cells with mechanical and chemical cues is a promising approach for guiding tissue repair and promoting tissue-scaffold integration. It is becoming increasingly clear that tuning scaffold rigidity is a powerful way to control cell function, but how scaffold rigidity regulates gene expression is not well-understood. Previously, we tested the hypothesis that substrate rigidity controls gene expression by tuning nuclear tension. We took advantage of the fact that the LINC (linker of nucleoskeleton-to-cytoskeleton) complex is a known molecular linker of the nucleus to the cytoskeleton, and asked how it regulates the sensitivity of genome-wide transcription to substrate rigidity. Our results were the first to show that the LINC complex facilitates mechano-regulation of expression across the genome. Combined with myosin inhibition studies, we were able to identify genes that depend on nuclear tension for their mechanosensitivity. In this continuation, we propose to identify molecular mechanisms for these highly novel findings.
Two specific aims are proposed:
Aim 1 : To identify the nuclear molecular linkers necessary for rigidity-mediated control of gene expression.
Aim 2 : To determine the mechanisms by which nuclear-cytoskeletal linkage regulates gene mechanosensitivity. Scientifically, this work addresses important and longstanding questions about the mechanisms by which the cell microenvironment controls gene expression. Clinically, the long-term impact of this work is to promote the rational development of new biomaterials with mechanical properties tuned for tissue engineering and repair. An additional benefit is the development of an integrated approach using both technologies from engineering and techniques from molecular cell biology for addressing a fundamental question in rigidity sensing. This work is of fundamental interest to diverse fields including cell-biomaterial interactions, nuclear and cell mechanics and molecular and cell biology of gene regulation. The project builds collaboration between the groups of Lele (University of Florida), Nickerson (University of Massachusetts Medical School) and Roux (Sanford Research). Each laboratory brings unique resources to this research including access and expertise in using sophisticated optical and electron microscopes, strong expertise with wet-bench cell and molecular biology experiments specifically related to the nucleus, and expertise in cell and nuclear mechanosensing and biomaterial development and characterization. The team will also benefit from the support of well-known molecular and cell biologists and bioengineers who have pioneered experimental techniques in a broad number of areas in LINC complex biology, nuclear/chromatin structure and function and tissue biomechanics.

Public Health Relevance

Many applications in tissue engineering involve cell culture on solid scaffolds with defined properties. We seek to improve scientific understanding of how scaffold properties regulate gene expression in cells. This will help improve our ability to control cells and hence engineer tissues with superior performance.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
2R01EB014869-05
Application #
9238291
Study Section
Biomaterials and Biointerfaces Study Section (BMBI)
Program Officer
Hunziker, Rosemarie
Project Start
2012-08-01
Project End
2020-06-30
Budget Start
2016-09-30
Budget End
2017-06-30
Support Year
5
Fiscal Year
2016
Total Cost
$464,931
Indirect Cost
$101,198
Name
University of Florida
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
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Tocco, Vincent J; Li, Yuan; Christopher, Keith G et al. (2018) The nucleus is irreversibly shaped by motion of cell boundaries in cancer and non-cancer cells. J Cell Physiol 233:1446-1454
Zhang, Qiao; Tamashunas, Andrew C; Lele, Tanmay P (2018) A Direct Force Probe for Measuring Mechanical Integration Between the Nucleus and the Cytoskeleton. J Vis Exp :
Lele, Tanmay P; Dickinson, Richard B; Gundersen, Gregg G (2018) Mechanical principles of nuclear shaping and positioning. J Cell Biol 217:3330-3342
Kent, Ian A; Lele, Tanmay P (2017) Microtubule-based force generation. Wiley Interdiscip Rev Nanomed Nanobiotechnol 9:
Nickerson, Jeffrey A; Wu, Qiong; Imbalzano, Anthony N (2017) Mammalian SWI/SNF Enzymes and the Epigenetics of Tumor Cell Metabolic Reprogramming. Front Oncol 7:49
Birendra Kc; May, Danielle G; Benson, Benjamin V et al. (2017) VRK2A is an A-type lamin-dependent nuclear envelope kinase that phosphorylates BAF. Mol Biol Cell 28:2241-2250
Kim, Dae In; Jensen, Samuel C; Noble, Kyle A et al. (2016) An improved smaller biotin ligase for BioID proximity labeling. Mol Biol Cell 27:1188-96
Torbati, Mehdi; Lele, Tanmay P; Agrawal, Ashutosh (2016) Ultradonut topology of the nuclear envelope. Proc Natl Acad Sci U S A 113:11094-11099
Neelam, Srujana; Hayes, Peter Robert; Zhang, Qiao et al. (2016) Vertical uniformity of cells and nuclei in epithelial monolayers. Sci Rep 6:19689

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