The Pelling Lab - University of Ottawa

University of Ottawa
L'Université Canadienne
Canada's University

Research

Overview: The Pelling Lab is generally interested in understanding dynamic mechanical properties of cellular systems across nanometer and micrometer length scales. Utilizing a combination of cell biology, molecular biology, physical and computational approaches we are attempting to understand the fundamental genetic and architectural control mechanisms of mechanotransduction pathways in cells and artificial tissues. A combination of biophysical tools allow us to probe the force transduction and repsonse pathways of single cells (adherent and non-adherent), multi-cellular aggregates and artifical tissues at local and global scales simultaneously controlling their mechancial, biochemical and physiological environments.

Location: The Pelling Lab is temporarily in D'Iorio Hall (DRO) while we await our new home in the Interdisciplinary Nano-Physics Centre currently under construction in the basement of MacDonald Hall.

Atomic Force Microscopy, Optical Stretcher and Optical Microscopy Lab - DRO320B
General and Molecular Biology Labs - DRO133 & DRO320A
Cell and Tissue Culture Lab - DRO228

Understanding Force Transduction Through The Cyto-Architecture

Utilizing simultaneous atomic force microscopy (AFM) and high speed resonant scanning confocal microscopy we are visualizing the deformation pathways through multiple elements of the cyto-architecture. Force transduction is controlled by multiple elements of the cytoskeleton in pathways dependent on the cell type, the physiological conditions and the properties of the mechanical microenvironment.

The AFM tip (red) above a live cell expressing GFP-Actin (green)

Personnel

Louise Guolla, Kristina Haase, Joan Macadangdang.

Publications

Silberberg, Y.R., Guolla, L. & Pelling, A.E. "Simultaneous AFM and Optical Approaches for Live Cell Nanomechanics." Dufrene, Y.F. ed. Life at the Nanoscale: Atomic Force Microscopy of Live Cells. Singapore: Pan Stanford Publishing (2010).
Pelling, A.E., Veraitch, F.S., Chu, C.P.K., Mason, C. & Horton, M.A. "Mechanical Dynamics of Single Cells During Early Apoptosis." Cell Motil. Cytoskeleton 66, 409 (2009).
Silberberg, Y.R., Pelling, A.E., Yakubov, G.E., Crum, W.R., Hawkes, D.J. & Horton, M.A. "Mitochondrial Displacements in Response to Nanomechanical Forces." J. Mol. Recognit. 21, 30 (2008).
Pelling, A.E., Nicholls, B.M., Silberberg, Y.S. & Horton, M.A. "Approaches for Investigating Mechanobiologial Dynamics in Living Cells with Combined Fluorescence and Atomic Force Microscopies." In Méndez-Vilas, A. and Díaz, J. eds. Modern Research and Educational Topics on Microscopy. Badajoz: Formatex, pp.3-10 (2007).

Mechanics of Cell Monolayers

In-vivo, cells are found within complex three dimensional environments in which the extra-cellular matrix, (ECM) cell-cell contacts/junctions and the mechanical properties of the surrounding micro-environment all play critical roles in governing and modulating the mechancial responses of cells to external forces. We are currently studying the role the ECM plays in determing the mechancial properties of cell sheets and its role in maintaining sheet integrity during cell death. We are also studying how mechanical forces are tranduced through cell sheets and the structural response of cellular monolayers to highly controlled mechancial stimulation.

Fibronectin (green), actin (red) and nuclei (blue) in a monolayer before (left) and after (right) the induction of apoptosis. The fibronectin network plays an important role in governinging and maintaining the mechanical properties of the sheet in both situations.

Actin (red) and nuclei (blue) an an MDCK cell monolayer.

Personnel

Kristina Haase, Jiashan Wang.

Publications

Wang, J. & Pelling, A.E. "Cell Sheet Integrity and Nanomechanical Breakdown During Programmed Cell Death"Medical & Biological Engineering & Computing In Press (2010).

Mechanical Microenvironments

The mechanical micro-environment (MME) is a critical factor in governing cellular responses to external forces and directing important physiological pathways such as apoptosis, differentiation and myogenesis. We have previously shown that the MME affects the mechancial breakdown of single cells during apoptosis by altering cytoskeletal remodelling possibly by modulating caspase activity. We are currently utilizing traction force microscopy (TFM) to study live cell mechanosensitivity in MME's which mimic working and resting tissues by examining cytoskeletal and focal adhesion remodelling during cellular traction force generation.

A live cell (left) expressing GFP-Actin (green, nucleus in blue) culutred on a mechanically tuneable flexible substrate embedded with 200nm red flouresecent fiduciary markers This allows us to perform TFM measurements (right) while imaging structural remodelling pathways in the cell.

Single cells undergoing apotosis display distinct mechanical signatures on plastic culture dishes (blue line). However, placing cells in MMEs which are much softer alter the mechancial dynamics and timing of distinct stages of cytoskeletal breakdown (black and red lines).

Personnel

Zeinab Al-Rekabi, Dominique Tremblay.

Publications

Al-Rekabi, Z. & Pelling, A.E. In Preparation (2010).
Al-Rekabi, Z., Harden, J.L. & Pelling, A.E. "Cellular Nanomechanics in Nanomedicine." In Bartul, Z. & Trenor, J. eds. Advances in Nanotechnology, Volume 2: Nova Science Publishers (2010).
Silberberg, Y.R., Guolla, L. & Pelling, A.E. "Investigating Mammalian Cell Nanomechanics with Simultaneous Optical and Atomic Force Microscopy." Dufrene, Y.F. ed. Life at the Nanoscale: Atomic Force Microscopy of Live Cells. Singapore: Pan Stanford Publishing, In Press (2010).
Pelling, A.E., Veraitch, F.S., Chu, C.P.K., Mason, C. & Horton, M.A. "Mechanical Dynamics of Single Cells During Early Apoptosis." Cell Motil. Cytoskeleton 66, 409 (2009).

Myotube Twitching

Cells generate a wide variety of mechancial motions at the plasma membrane due to thermal fluctuations, cytosketal remodelling and contractile motion. In the past we have employed the AFM as an ultrasensitive motion detector to measure and record these small scale motions and oscillations. Currently, we are studying spontaneous contractions in muscle myotubes and cardiomyocytes.

AFM tip resting on a spontaneously contracting muscle myotube (nuclei are blue).

AFM based measurement of cardiomyocyte contractions.

Personnel

Jiashan Wang.

Publications

Pelling, A.E., Veraitch, F.S., Chu, C.P.K., Nicholls, B.M., Hemsley, A.L., Mason, C. & Horton, M.A. "Mapping Correlated Membrane Pulsations and Fluctuations in Human Cells." J. Mol. Recognit. 20, 467 (2007).
Pelling, A.E., Sehati, S., Gralla, E.B. & Gimzewski, J.K. "Time Dependence of the Frequency and Amplitude of the Local Nanomechanical Motion of Yeast." Nanomedicine 1, 178 (2005).
Pelling, A.E., Sehati, S., Gralla, E.B., Valentine, J.S. & Gimzewski, J.K. "Local Nanomechanical Motion of the Cell Wall of Saccharomyces cerevisiae." Science 304, 1147 (2004).

Instrumentation Development - The Optical Stretcher

We are currently constructing an Optical Stretcher in collaboration with Dr. Jochen Guck (University of Cambridge). This tool will allow us to optically trap and mecancially stimulate cells within a microfluidic environment. One major goal will be to image internal force transduction pathways in non-adherent cells which are free of mechanical links tot he micro-environment.

The Optical Stretcher platform in the Pelling Lab.

Our visit to the Cavendish Labs at the University of Cambridge to see the Stretcher's in action.

A trapped cell in a microfluidic channel.

Personnel

Joan Macadangdang.

Collaborators and Partners

Jochen Guck (University of Cambridge)
Farlan Veraitch (University College London)
Buzz Baum (University College London)
Michel Godin (University of Ottawa)
James Harden (University of Ottawa)
Nikon Canada

Funding

Discovery Grant Discovery Accelerator Supplement Research Tools and Instruments	Ontario Research Fund Early Researcher Award
	Leaders Opportunity Fund Infrastructure Operating Fund