Cellular 'glue' helps epithelial tissues engulf dead cells while staying sealed

Researchers at the Centre for Genomic Regulation in Barcelona have discovered that a protein known as E-cadherin, which helps cells and tissues stick together, also plays a role in helping epithelial cells engulf nearby dead cells. This finding could provide new insights into chronic inflammatory conditions, as the debris of dying cells is a major contributor to inflammation.

The study, published in Nature Communications, focuses on the E-cadherin complex, which is made up of E-cadherin and three other proteins that work together to provide structural support to tissues. Dr. Verena Ruprecht, the senior author of the study, explains that the cells responsible for engulfing the dead cells are constrained by a barrier that must remain impermeable.

To enable this process, the top surface of a cell stretches and wraps around the dead cell, while the bottom surface, which faces the outside world or an open space, stays still and maintains the sealed barrier. The study found that a specific protein within the E-cadherin complex acts as a tether, anchoring the assembly to the cell's internal skeleton to transmit force during the engulfing process.

Removing this tethering protein or its specific binding site prevents the cell from engulfing dead cells. Additionally, another protein within the complex functions as a brake for the cell's contractile motor. If this brake is removed, the cell becomes too stiff to effectively clear the dead cells. The researchers also investigated whether this mechanism exists in mammals, and found that blocking E-cadherin in early mouse embryos resulted in dying cells remaining uncleared, suggesting that the mechanism is shared across vertebrates.

This discovery could lead to further understanding of how the body removes dying cells, which is crucial for maintaining tissue integrity and preventing chronic inflammation.