An ‘electric’ Travelling Fellowship – putting transmembrane potential to the measure.

3 March 2023

Sofia and her co-workers from the travelling fellowship.

The transmembrane potential (Vmem) is the difference in electrical potential across a cell membrane, acute changes in Vmem can result in multiple differences in cellular signalling pathways and cell processes such as differentiation, proliferation and cell:cell communication.

Sofia Masuelli, a student at The Institute of Histology and Embryology of Mendoza used a travelling fellowship from Journal of Cell Science to visit the Michael Levin Lab and the Madeleine Oudin Lab at Tufts University, Massachusetts, USA. The grant enabled her to explore the bioelectric and epigenetic differences between left- and right-sided breast cancer, inside a cancerous MMTV-PYMT mouse model.

The MMTV-PYMT cell line used in Sofia’s research is prone to the spontaneous development of mammary tumours, those that closely resemble the progression and morphology of human breast cancers.

After the successful incubation of the MMTV-PYMT cells with two fluorescent probes, the anionic DiBAC4 (Db) and the cationic MitoTracker (Mt), Sofia and her colleagues were able to use confocal microscopy techniques to calculate the Mt/Db probe ratio (relative to a control) observed in the images.

Sofia later concluded that five of the mice had right-sided tumours that were more hyperpolarised (had a greater difference in Vmem) compared to those found on the left.

Mice breast tumours with DiBAC (green) and Mitotracker (red) seen through confocal microscopy.
Mice breast tumours with DiBAC (green) and Mitotracker (red) observed through confocal microscopy.

The successful breakthrough with the confocal microscopy results were further validated, as Sofia had the opportunity to analyse the MMTV-PYMT tumours through flow cytometry. After observing an increased Mt/Db ratio in the right-sided tumours once again, Sofia and the host lab sent the extracted MMTV-PYMT tumours DNA, RNA and protein samples off to perform further analysis to study if the bioelectric differences observed between left and right tumours are related to cancer features such as proliferation.

All these interesting results have helped Sofia to progress in the writing of  her thesis which will be published soon at an international journal. The Company of Biologists Travelling Fellowship allowed Sofia to have this great academic and personal experience at Tufts University and established a collaboration with the Levin and Oudin Lab.

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