Our research interests focus on
1) quantifying spatial and temporal dynamics of proteins during cell migration,
2) characterizing metabolic alterations in cells and tissues and
3) developing novel imaging technologies.
Cell migration is vital for embryonic development, wound healing, and cancer metastasis. We are using the cutting edge biophysical tools to monitor molecular interactions in live cells and how their activity in spatial locations mediates cell migration. Using the raster image correlation spectroscopy (RICS) method and the Number and Molecular Brightness (N&B) analysis we have revealed the dynamic assembly and disassembly of focal adhesions as well as determined the aggregation and stoichiometry of protein interaction. In particular we are investigating tumor invasion and executing a strategy to monitor signaling for cells migrating in 3D matrices and in tissues.
RICS along a line from the nano-scale precise imaging by rapid beam oscillation (nSPIRO) method. The orbit in this example is not smooth and only along one position along the cell protrusion. The intensity is plotted as a function of time and the time segments are cut into short time intervals or frames. The fluorescence intensities are correlated along the x and y axis as a function of time and space.
Current Project in the lab: We are addressing specific questions in each of these areas to quantitatively access: protein interactions, changes in energy metabolism or map molecular mobility and paths that proteins follow in the nucleus and cytosol in quest finding binding and enzymatic action sites.
- Develop imaging platforms for 3D orbital tracking: mitochondria in tumor cells plated in collagen and in vivo
- Analyzing the “Metabolic Index” using the Phasor/FLIM method for:
a) Huntington disease: Alterations of energy metabolism
b) Switch in energy metabolism in cancer cells dependent on mechanosensing
Sameni, S., Syed, A., Marsh, J. L. & Digman, M. A. The phasor-FLIM fingerprints reveal shifts from OXPHOS to enhanced glycolysis in Huntington Disease. Sci Rep 6, 34755, doi:10.1038/srep34755 (2016).
Sameni, S., Malacrida, L., Tan, Z. & Digman, M. A. Alteration in Fluidity of Cell Plasma Membrane in Huntington Disease Revealed by Spectral Phasor Analysis. Scientific Reports 8, 734, doi:10.1038/s41598-018-19160-0 (2018).
What’s going on with the development of the Phasor/FLIM method? Calculating the ABSOLUTE concentration of NADH: