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Botcherby E.J.,University of Oxford | Corbett A.,University of Oxford | Burton R.A.B.,University of Oxford | Smith C.W.,University of Oxford | And 7 more authors.
Circulation Research | Year: 2013

RATIONALE:: Sarcomere length (SL) is a key indicator of cardiac mechanical function, but current imaging technologies are limited in their ability to unambiguously measure and characterize SL at the cell level in intact, living tissue. OBJECTIVE:: We developed a method for measuring SL and regional cell orientation using remote focusing microscopy, an emerging imaging modality that can capture light from arbitrary oblique planes within a sample. METHODS AND RESULTS:: We present a protocol that unambiguously and quickly determines cell orientation from user-selected areas in a field of view by imaging 2 oblique planes that share a common major axis with the cell. We demonstrate the effectiveness of the technique in establishing single-cell SL in Langendorff-perfused hearts loaded with the membrane dye di-4-ANEPPS. CONCLUSIONS:: Remote focusing microscopy can measure cell orientation in complex 2-photon data sets without capturing full z stacks. The technique allows rapid assessment of SL in healthy and diseased heart experimental preparations. © 2013 American Heart Association, Inc. Source


Raynaud C.M.,Qatar Cardiovascular Research Center | Rafii A.,Cornell College
Stem Cells International | Year: 2013

Cell therapy has emerged as a potential therapeutic strategy in regenerative disease. Among different cell types, mesenchymal stem/stromal cells have been wildly studied in vitro, in vivo in animal models and even used in clinical trials. However, while clinical applications continue to increase markedly, the understanding of their physiological properties and interactions raises many questions and drives the necessity of more caution and supervised strategy in their use. © 2013 Christophe Michel Raynaud and Arash Rafii. Source


Johnson-Kerner B.L.,Rproject Als Jenifer Estess Laboratory For Stem Cell Research | Johnson-Kerner B.L.,Columbia University | Johnson-Kerner B.L.,University of California at San Francisco | Ahmad F.S.,New York Stem Cell Foundation | And 14 more authors.
Human Molecular Genetics | Year: 2015

Giant axonal neuropathy (GAN) is a progressive neurodegenerative disease caused by autosomal recessive mutations in the GAN gene resulting in a loss of a ubiquitously expressed protein, gigaxonin. Gene replacement therapy is a promising strategy for treatment of the disease; however, the effectiveness and safety of gigaxonin reintroduction have not been tested in human GAN nerve cells. Herewe report the derivation of induced pluripotent stem cells (iPSCs) from three GAN patients with different GAN mutations. Motor neurons differentiated from GAN iPSCs exhibit accumulation of neurofilament (NF-L) and peripherin (PRPH) protein and formation of PRPH aggregates, the key pathological phenotypes observed in patients. Introduction of gigaxonin either using a lentiviral vector or as a stable transgene resulted in normalization of NEFL and PRPH levels in GAN neurons and disappearance of PRPH aggregates. Importantly, overexpression of gigaxonin had no adverse effect on survival of GAN neurons, supporting the feasibility of gene replacement therapy. Our findings demonstrate that GAN iPSCs provide a novel model for studying human GAN neuropathologies and for the development and testing of new therapies in relevant cell types. © The Author 2014. Source


Lohezic M.,University of Oxford | Bollensdorff C.,Imperial College London | Bollensdorff C.,Qatar Cardiovascular Research Center | Korn M.,RAPID Biomedical GmbH | And 5 more authors.
Magnetic Resonance in Medicine | Year: 2015

Purpose (i) To optimize an MR-compatible organ perfusion setup for the nondestructive investigation of isolated rat hearts by placing the radiofrequency (RF) coil inside the perfusion chamber; (ii) to characterize the benefit of this system for diffusion tensor imaging and proton (1H-) MR spectroscopy. Methods Coil quality assessment was conducted both on the bench, and in the magnet. The benefit of the new RF-coil was quantified by measuring signal-to-noise ratio (SNR), accuracy, and precision of diffusion tensor imaging/error in metabolite amplitude estimation, and compared to an RF-coil placed externally to the perfusion chamber. Results The new design provided a 59% gain in signal-to-noise ratio on a fixed rat heart compared to using an external resonator, which found reflection in an improvement of living heart data quality, compared to previous external resonator studies. This resulted in 14-29% improvement in accuracy and precision of diffusion tensor imaging. The Cramer-Rao lower bounds for metabolite amplitude estimations were up to 5-fold smaller. Conclusion Optimization of MR-compatible perfusion equipment advances the study of rat hearts with improved signal-to-noise ratio performance, and thus improved accuracy/precision. Magn Reson Med 73:2398-2405, 2015. © 2014 The Authors. Source


Gajendrarao P.,Qatar Cardiovascular Research Center | Krishnamoorthy N.,Qatar Cardiovascular Research Center | Kassem H.S.,National Programme at Aswan Heart Center | Moharem-Elgamal S.,National Programme at Aswan Heart Center | And 6 more authors.
PLoS ONE | Year: 2013

Cardiac myosin binding protein-C (cMyBP-C) is a multi-domain (C0-C10) protein that regulates heart muscle contraction through interaction with myosin, actin and other sarcomeric proteins. Several mutations of this protein cause familial hypertrophic cardiomyopathy (HCM). Domain C1 of cMyBP-C plays a central role in protein interactions with actin and myosin. Here, we studied structure-function relationship of three disease causing mutations, Arg177His, Ala216Thr and Glu258Lys of the domain C1 using computational biology techniques with its available X-ray crystal structure. The results suggest that each mutation could affect structural properties of the domain C1, and hence it's structural integrity through modifying intra-molecular arrangements in a distinct mode. The mutations also change surface charge distributions, which could impact the binding of C1 with other sarcomeric proteins thereby affecting contractile function. These structural consequences of the C1 mutants could be valuable to understand the molecular mechanisms for the disease. © 2013 Gajendrarao et al. Source

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