Polarized Light Observations on Striated Muscle Contraction in a Mite

Aronson, John F.

doi:10.1083/jcb.32.1.169

Cited by 7 publications

(3 citation statements)

References 10 publications

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“…This observation suggests that our bright-field analysis tool can be improved in future studies, perhaps by segmenting cell features before analysis to eliminate potential image artifacts 44 or by using polarized light to better capture sarcomeres. 45 However, segmentation of cell area requires a clear intensity difference between the cell ROI and its exterior. A decrease in maximal sarcomere length and values of sarcomere shortening similar to baseline (no ISO) was observed for 1 μM, suggesting a decrease in intracellular tension at this concentration.…”

Section: Discussionmentioning

confidence: 99%

Multi-Imaging Method to Assay the Contractile Mechanical Output of Micropatterned Human iPSC-Derived Cardiac Myocytes

Ribeiro

Schwab

Mandegar

et al. 2017

Circulation Research

105

117

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Rationale During each beat, cardiac myocytes generate the mechanical output necessary for heart function through contractile mechanisms that involve shortening of sarcomeres along myofibrils. Human induced pluripotent stem cells can be differentiated into cardiac myocytes that model cardiac contractile mechanical output more robustly when micropatterned into physiological shapes. Quantifying the mechanical output of these cells enables us to assay cardiac activity in a dish. Objective We sought to develop a computational platform that integrates analytical approaches to quantify the mechanical output of single micropatterned cardiac myocytes from microscopy videos. Methods and Results We micropatterned single cardiac myocytes differentiated from human induced pluripotent stem cells on deformable polyacrylamide substrates containing fluorescent microbeads. We acquired videos of single beating cells, of microbead displacement during contractions, and of fluorescently labeled myofibrils. These videos were independently analyzed to obtain parameters that capture the mechanical output of the imaged single cells. We also developed novel methods to quantify sarcomere length from videos of moving myofibrils and to analyze loss of synchronicity of beating in cells with contractile defects. We tested this computational platform by detecting variations in mechanical output induced by drugs and in cells expressing low levels of myosin binding protein C. Conclusions Our method can measure cardiac function in cardiac myocytes differentiated from induced pluripotent stem cells and determine contractile parameters that can be used to elucidate the mechanisms that underlie variations in cardiac myocyte function. This platform will be amenable to future studies of the effects of mutations and drugs on cardiac function.

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Section: Discussionmentioning

confidence: 99%

Multi-Imaging Method to Assay the Contractile Mechanical Output of Micropatterned Human iPSC-Derived Cardiac Myocytes

Ribeiro

Schwab

Mandegar

et al. 2017

Circulation Research

105

117

View full text Add to dashboard Cite

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“…Figure 5A and the corresponding through-focus video Video 7 show images of fixed iPSC-derived CMs with the labelfree channels (phase and principal retardance) and the fluorescence channels. Polarized light imaging has played an important role in understanding architecture and activity of sarcomeres (65) (fig. 5B).…”

Section: E: Multiplexing Of Upti and Fluorescence For Imaging Cardiommentioning

confidence: 99%

uPTI: uniaxial permittivity tensor imaging of intrinsic density and anisotropy

Yeh

Ivanov

Guo

et al. 2020

Preprint

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Architecture of biological systems is important for their homeostatic functions and is predictive of pathology. Volumetric imaging of intrinsic density, anisotropy, and 3D orientation of cell and tissue components is informative, but still challenging. These physical properties can be described succinctly by the volumetric distribution of the specimen’s permittivity tensor (PT). We report uniaxial permittivity tensor imaging (uPTI), a novel approach for label-free volumetric imaging with diffraction-limited resolution. uPTI combines the oblique illumination and the polarization imaging with high numerical apertures to encode the specimen’s permittivity tensor into intensity modulations, which are decoded with a novel vector diffraction model and a multi-channel convex optimization. The uPTI volumes of polystyrene beads and laser-fabricated anisotropic glass targets show that 3D uPT measurements are quantitative, with diffraction-limited spatial resolution of 0.23 × 0.23 × 0.8 μm3. Automated 2D and 3D imaging of a mouse brain section reveals anatomy at multiple scales (cm – 250 nm) and demonstrates that uPTI enables analysis of the density, anisotropy, and orientation of axon bundles and single axons. We multiplex uPTI with fluorescence de-convolution microscopy to enable correlative analysis of physical and molecular architecture of iPSC-derived cardiomyocytes. uPTI can be added to an existing widefield microscope as a low cost module. We share our implementation of the forward model and optimization algorithms via open source repository. Collectively, the reported advances in optical design, image formation, reconstruction algorithms, and biological interpretation open multiple avenues to study architecture of organelles, cells and tissue sections, including human cells and tissues that are challenging to label.

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“…The A-band does not appear to have been decreased to one-half its resting length as deVillafranca (196I) and deVillafranca and Marschhaus (1963) have observed with glycerinated horseshoe crab muscle. Instead, the length appears to remain rather constant (Aronson, 1967). X 1080.…”

Section: Glycogenmentioning

confidence: 99%

Fine structure and physiology of cardiac muscle in the spider, Dugesiella hentzi

Johnson

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Polarized Light Observations on Striated Muscle Contraction in a Mite

Cited by 7 publications

References 10 publications

Multi-Imaging Method to Assay the Contractile Mechanical Output of Micropatterned Human iPSC-Derived Cardiac Myocytes

Multi-Imaging Method to Assay the Contractile Mechanical Output of Micropatterned Human iPSC-Derived Cardiac Myocytes

uPTI: uniaxial permittivity tensor imaging of intrinsic density and anisotropy

Fine structure and physiology of cardiac muscle in the spider, Dugesiella hentzi

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