Abstract 11749: Cell-Specific Expression of Voltage-Sensitive Protein Confirms Cardiac Myocyte to Non-Myocyte Electrotonic Coupling in Healed Murine Infarct Border Tissue
Bibliographic record
Abstract
Introduction: Heterocellular electrotonic coupling of cardiac myocytes and non-myocytes is common in vitro , yet its presence, extent and role in vivo are debated. Optogenetic tools provide a unique means for cell-specific assessment of electrophysiology. Here, we utilise the genetically-encoded voltage-sensitive fluorescent protein 2.3 (VSFP2.3) to monitor transmembrane potential (Vm) in myocytes or fibroblasts of isolated murine hearts. Methods: Transgenic mice expressing VSFP2.3 under the control of either alpha-myosin heavy chain promoter (αMHC; myocytes) or Wilm’s tumor promoter (WT1; fibroblasts) were generated by Cre-LoxP recombination. Infarcts (left ventricular freewall) were caused by cryoablation, followed by 8 weeks recovery. Vm was measured in mechanically-uncoupled (10μM blebbistatin) Langendorff-perfused hearts by simultaneous collection of VSFP2.3 donor (mCerulean; CFP) and acceptor (citrine; YFP), or of VSFP2.3 YFP and voltage-sensitive dye (di-4-ANBDQPQ) signals, using an EMCCD camera (128х128 pixels, 511Hz) on an upright microscope (10х water-immersion lens). Cell-specificity of transgene expression was confirmed post hoc by immunohistochemistry (myomesin for myocytes, vimentin for fibroblasts) using confocal microscopy. Results: Cardiomyocyte action potentials (AP) were successfully measured in αMHC-VSFP2.3 mice by CFP/YFP ratiometry. After adding di-4-ANBDQPQ to these hearts, signal comparison reconfirmed slower AP upstroke and repolarisation kinetics of VSFP2.3 (Fig.A). Strikingly, myocyte-like AP were also recorded, in (dye-free) WT1-VSFP2.3 hearts, from fibroblasts at the infarct border zone (Fig.B). Conclusions: Results demonstrate the utility of VSFP2.3 for cell-specific cardiac electrophysiology research. In addition, observation of AP-like potentials in non-excitable cells confirms in vivo electrotonic coupling of cardiac myocytes and non-myocytes in healed murine infarct border tissue. ![][1] [1]: /embed/graphic-1.gif
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".