LRRC10 Reveals Path to Mature Heart Cells

Researchers from the group of Jeroen Bakkers at the Hubrecht Institute recently discovered a mechanism driving the maturation of heart muscle cells during regeneration processes. This mechanism, known as LRRC10, was found to have a similar effect on mouse and human heart muscle cells. The findings, published in Science, offer hope for developing novel therapies against cardiovascular diseases.

When a heart attack occurs, a blood clot blocks the flow of nutrients and oxygen to parts of the heart, resulting in the death of heart muscle cells and eventual heart failure. Although treatments exist to manage symptoms, no cure can replace lost tissue with functional, mature heart muscle cells. 

Unlike humans, zebrafish possess a remarkable ability to regenerate their hearts fully within 90 days of damage. The surviving heart muscle cells in zebrafish can divide and generate new cells, providing a natural source of tissue replacement. However, the process by which these newly formed cells mature and integrate into the existing heart tissue has remained a mystery.

To unravel this mystery, the researchers developed a technique for culturing thick slices of injured zebrafish hearts outside the body. This allowed them to observe live imaging of calcium movement within the heart muscle cells, a crucial indicator of cell maturity. They discovered that the calcium movement in newly divided cells gradually transitioned from an embryonic-like pattern to a mature pattern over time. The researchers identified LRRC10, a component of the cardiac dyad responsible for calcium handling, as a critical player in halting cell division and promoting maturation. Without LRRC10, heart muscle cells continued to divide and remained immature.

Excited by these findings, the researchers investigated whether LRRC10's effects could be translated to mammalian cells. They induced the expression of LRRC10 in mouse and lab-grown human heart muscle cells and observed similar changes in calcium handling, reduced cell division, and increased maturation, mirroring the results seen in zebrafish. This translational potential opens up new possibilities for using LRRC10 in the context of regenerative therapies for patients.

By harnessing LRRC10 to control calcium handling and drive the maturation of heart muscle cells, scientists may be able to address the limited regenerative capacity of the mammalian heart. This has potential implications for transplantation therapies, as lab-grown heart muscle cells treated with LRRC10 could mature and integrate more effectively into the damaged heart tissue. Additionally, LRRC10 could enhance the relevance of current models for studying cardiac diseases, as the immaturity of lab-grown heart muscle cells has been a contributing factor to the low success rate of drug candidates in the past.

As the quest for new therapies continues, integrating LRRC10 into the development of lab-grown heart muscle cells holds promise for improving the lives of patients affected by cardiovascular diseases.