Our new review article to mark 10 years since the first super-resolution imaging experiments on cardiac muscle:
Abstract: Remodelling of the membranes and protein clustering patterns during the pathogenesis of cardiomyopathies has renewed the interest in spatial visualisation of these structures in cardiomyocytes. Coincidental emergence of single molecule (super-resolution) imaging and tomographic electron microscopy tools in the last decade have led to a number of new observations on the structural features of the couplons, the primary sites of excitation-contraction coupling in the heart. In particular, super-resolution and tomographic electron micrographs have revised and refined the classical views of the nanoscale geometries of couplons, t-tubules and the organisation of the principal calcium handling proteins in both healthy and failing hearts. These methods have also allowed the visualisation of some features which were too small to be detected with conventional microscopy tools. With new analytical capabilities such as single-protein mapping, in situ protein quantification, correlative and live cell imaging we are now observing an unprecedented interest in adapting these research tools across the cardiac biophysical research discipline. In this article, we review the depth of the new insights that have been enabled by these tools toward understanding the structure and function of the cardiac couplon. We outline the major challenges that remain in these experiments and emerging avenues of research which will be enabled by these technologies.
Read the full text using this link
Nanodomains are naturally assembled signaling stations, which facilitate fast and highly regulated signaling within and between cells. Calcium (Ca2+) nanodomains known as junctional membrane complexes (JMCs) transduce fast and highly synchronized intracellular signals, which are required by a variety of cell types. Common to most such nanodomains are clustered assemblies of the principal intracellular Ca2+ release channels, ryanodine eceptors (RyRs). JMCs found in cardiac muscle cells have been studied extensively as self-assembled clusters of RyR. While known to form crystalline arrays in vitro, the organization of RyRs in situ within the JMCs has been less clear. The development of single-molecule localization microscopy (SMLM or super-resolution) optical methods have transformed our ability to visualize and accurately quantify the spatial geometries and sizes of RyR clusters. The recent application of the novel DNA-PAINT super-resolution technology has exploited an unprecedented optical resolution of 10–15 nm to visualize the natural arrays of RyRs within JMCs. In this chapter, we review the key insights into the in situ RyR assembly within cardiac nanodomains that have been gained over the last decade with the utility of super-resolution microscopy and the major considerations in interpreting and validating such image data.
To request a preprint version of the chapter, please contact the authors via Researchgate.
Full text of the chapter can be accessed via this direct link.
Miriam recently entered the ‘Three Minute Thesis’ competition held at The University of Leeds. A video of the presentation has since been uploaded to the conference YouTube channel which you can access here. A particular highlight of this competition for Miriam was hearing fellow researchers from a variety of disciplines communicate the wide-ranging impact of their research. The other presentations on the channel are a wonderful demonstration of this.
Isuru attended the second annual Edinburgh Super Resolution Imaging Consortium (ESRIC) symposium, held this year at the Institute of Genetics and Molecular Medicine (IGMM) of the University of Edinburgh (UoE). His talk on the Molecular-scale imaging of ryanodine receptors at both the cell surfaces and interiors with the adaptation of DNA-PAINT was well-received by a range of researchers based in Edinburgh and regionally in Europe.
Highlights from this meeting included a number of world class investigations led by research fellows and academics in UoE and Heriot Watt University. Of note, were Dr Colin Rickman’s talk on using naturally occurring enzymes as super-resolution imaging probes, Dr Lynn Paterson’s adaptation of optofluidic devices and optical tweezers for developing novel optical tools for cell biology. The plenary speaker was Prof Christophe Zimmer (from Institut Pasteur) who spoke about the adaptation of artificial neuronal networks (a tool called ANNA-PALM) to speed up super-resolution microscopy and demonstrate high throughput imaging of structures such as microtubules, nuclear pore complexes and mitochondria. We now eagerly anticipate his paper on ANNA-PALM out in press very soon.
The conference was organised by Dr Ann Wheeler and colleagues of the ESRIC and showcased their world class line up of microscopy platforms including a state-of-the-art Nikon STORM and SIM instrument and a Leica STED system.
On the back of our recent publication in Cell Reports, our research has enjoyed a wide ranging body of TV coverage. This included 20+ online newspapers and science & technology websites. Among this coverage, was a brief recording for the local television station Made in Leeds which was featured on the 6:30pm news on 11/1/2018.
Here is the link to a clip where Isuru is explaining the context and the value of the super-resolution microscopy technology in studying both healthy and disease physiology of the heart. Featured in the video, was Miriam during one of her imaging experiments.