Imperial College London

DrEricDubuis

Faculty of MedicineNational Heart & Lung Institute

Research Fellow
 
 
 
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Contact

 

+44 (0)20 7594 8427e.dubuis

 
 
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Location

 

102Sir Alexander Fleming BuildingSouth Kensington Campus

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Summary

 

Airways physiology

Airway innervation

 

 

asniOver the last few decades, there has been an explosion of scientific publications reporting the many and varied roles of transient receptor potential (TRP) ion channels in physiological and pathological systems throughout the body. We want to characterise the role of TRP channels present in the airways under normal and diseased conditions.

Airways innervating neuron stained with retrograde cellular tracker DiI

 

 

AWstainedAWst-comp

 

 

 

 

 

trp channels in airways

Over the last few decades, there has been an explosion of scientific publications reporting the many and varied roles of transient receptor potential (TRP) ion channels in physiological and pathological systems throughout the body. We want to characterise the role of TRP channels present in the airways under normal and diseased conditions.

A1V1coughThe current work focus mainly on the pathogenesis and symptoms of asthma and chronic cough diseases and the role of four members of the TRP family involved environmental and temperature change sensing : TRPA1, TRPV1, TRPV4 and TRPM8.

Innovation

show research

Ptychography is a new technology devellopped by Phase focus Ltd.  This label free technique allow to record live the morphological changes which happen in cultured cells while preserving the homeostasy of the cells. This technique can be used to record cell motility, nucleus division stages and mitosis and present great possibilities for measuring smooth muscle cells isotonic contraction, isotonic meaning the free contraction of the cell without any force opposing it.

When smooth muscle cells contract, unlique striated and cardiac muscle, they do so in an organised chaos. many unorganised contractile filaments connected to various parts of the membrane shorten triggering the tightening of the cell.

Organised muscle cells, such as cardiac or striated, or skeletal, muscle cells will shorten or contract following a specific axis or direction thanks to their organised contractile protein network. The smooth muscle cells however has a disorganised network of contractile proteins pseudo randomly attached to the membrane and when the cell contract it resuls in a slight shortening along their longitudinal axis but also in all other direction resulting in 3D contraction and it look like the cell is "swelling" like a ballon which is being inflated with lot of blebs appearing on its membrane. Cellular contraction

A consequence of this type of contraction is that it is difficult to measure and quantify. The best way to quantify it would be to measure the swelling of the cell and its change width and height alonside the modification of its DiI on ASMsilhouette as seen from above, aka its 2D surface area. Such measurement can be made using dyes which label the cell mmebrane and confocal microscope which recreate the 3D image of the cell however such measurements are time consuming, and are not amenable to record live the contraction of the cell in a time lapse fashion. Another point to consider is the effect of the dye which is lodge into the membrane on the bound membrane protein and ion channel function which play a crucial role on smooth muscle cell activity.

Phase focus used a system called ptychography where a low intensity near infrared laser is shown though the sample, in this case live cells in their culture medium, via different angles and an algorythm calculate the structure which induced changes in the laser coherence, intensity and  directionality. Thus the software calculate the shape of the cells live as they respond to stimuli. This allow us to assess the mechanism of drugs designed to prevent or relax the contraction of airway smooth muscle (ASM) cells staying as close as possible to physiological condition, without disturbing the cells by using foreign dyes, while isolation the ASM from the other cell types present in the airway which could influence the responses of the ASM and prevent a clear understanding of how drugs act on them.

                                     Ptychography:

ASM ptychography

The pictures above show ASM relaxed and contracted and the software represented the cells brighter as they become thicker