title: A spatiotemporal characterization method for the dynamic cytoskeleton.
abstract: The significant gap between quantitative and qualitative understanding of cytoskeletal function is a pressing problem; microscopy and labeling techniques have improved qualitative investigations of localized cytoskeleton behavior, whereas quantitative analyses of whole cell cytoskeleton networks remain challenging. Here we present a method that accurately quantifies cytoskeleton dynamics. Our approach digitally subdivides cytoskeleton images using interrogation windows, within which box-counting is used to infer a fractal dimension (Df ) to characterize spatial arrangement, and gray value intensity (GVI) to determine actin density. A partitioning algorithm further obtains cytoskeleton characteristics from the perinuclear, cytosolic, and periphery cellular regions. We validated our measurement approach on Cytochalasin-treated cells using transgenically modified dermal fibroblast cells expressing fluorescent actin cytoskeletons. This method differentiates between normal and chemically disrupted actin networks, and quantifies rates of cytoskeletal degradation. Furthermore, GVI distributions were found to be inversely proportional to Df , having several biophysical implications for cytoskeleton formation/degradation. We additionally demonstrated detection sensitivity of differences in Df and GVI for cells seeded on substrates with varying degrees of stiffness, and coated with different attachment proteins. This general approach can be further implemented to gain insights on dynamic growth, disruption, and structure of the cytoskeleton (and other complex biological morphology) due to biological, chemical, or physical stimuli. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Biomedical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Ghada
authors.initials: G
authors.lastname: Alhussein
authors.affiliation: Department of Biomedical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Aya
authors.initials: A
authors.lastname: Shanti
authors.affiliation: Department of Applied Mathematics and Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Ilyas A H
authors.initials: IA
authors.lastname: Farhat
authors.affiliation: Department of Biomedical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Sara B H
authors.initials: SB
authors.lastname: Timraz
authors.affiliation: School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors.forename: Noaf S A
authors.initials: NS
authors.lastname: Alwahab
authors.affiliation: Department of Applied Mathematics and Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Yanthe E
authors.initials: YE
authors.lastname: Pearson
authors.affiliation: Department of Applied Mathematics and Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Martin
authors.affiliation: Department of Biomedical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Christoforou
authors.affiliation: Department of Biomedical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
authors.forename: Jeremy C M
authors.initials: JC
authors.lastname: Teo
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism*; D020405:Dermis / Q000166:cytology / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008856:Microscopy, Fluorescence
chemical_list: D000199:Actins
keywords: cytoskeleton rearrangement; high-throughput analysis; live-imaging; mechanobiology; temporal analysis