Rapid heartbeat mystery uncovered

What is a gene found in the cells of the heart doing in our lungs and why does it trigger a dangerously rapid heart-beat in some patients?

Rhonda Taylor
Dr Rhonda Taylor

Those were the questions going through the mind of PhD student Jordan Boutilier who was working in the laboratories at the Harry Perkins Institute of Medical Research investigating a severe rare muscle disease.

He was hunting for the genes that control muscle movement when he noticed a gene called cardiac actin was present in the lung.

He started researching more widely and found that as early as the 1870s there were publications that showed that there are small populations of contractile muscle in the lung.

These heart-like cells surround the pulmonary veins and its thought their contracting pulse squeezes the vessels that take oxygenated blood to the heart. They contract to a rhythm, but not to the same beat as the heart.

Research Associate Dr Rhonda Taylor subsequently discovered a 1999 publication that showed this independent beating of cells in the lung could trigger atrial fibrillation in some patients. It seemed these cells were interfering with the electrical rhythm of the heartbeat.

She then led a team from the Perkins, the Lions Eye Institute and UWA to find out what was causing these cells, in some patients, to do more than just contract.

Why were they acquiring an electrical capacity that was interfering with the electrical signals in the heart?

“We thought it might have something to do with the genes of these cells,” she said.

The team started investigating to see if they could identify which genes are turned on or off in the heart-like cells in the lung.

“This was challenging because they are a very small population of cells deeply embedded in the lung, they are hard to reach and hard to isolate to look at them.

“So we took publicly available data and mined it”, said Dr Taylor.

As a result the team was able to identify the group of genes likely to be found in this particular heart cell in the lung.

This was new information.

They also found a very big lead gene, called Titan, which appears to regulate a number of other genes that could cause the cells to have an electrical function.

The team’s work has now been published.

“We don’t have funding to continue the research, so we are hoping that by publishing the work other researchers will pick it up.”

Rhonda hopes the discovery of the genes causing atrial fibrillation will lead to new treatments.

More than 33 million patients are affected globally by atrial fibrillation. It is a significant factor in stroke, heart failure and increased rates of death. 

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