Cells speed up wound repair by fusing together

Researchers studied wound healing in fruit fly pupae using live microscopy. They found that nearly half of the epithelial cells, the cells that line the tissue surface, surrounding a wound fuse into large cells with multiple nuclei. These merged cells are called syncytia.

When the gene Atg1, involved in cellular recycling (autophagy), was switched off, fewer syncytia formed and wound closure slowed. The study, published in eLife, also shows that a computational model of tissue fluidity predicts cell fusion can reduce wound closure time by roughly one third.

Three mechanisms in one

Syncytia help in multiple ways simultaneously. They move faster toward wound edges than ordinary cells and take the lead in the initial sealing. They reduce the need for cell rearrangement as the tissue closes. And they pool the resources of their component cells toward where they are most needed. Three advantages in a single cell.

For longevity science, this is interesting because tissue repair declines with aging. Older organisms heal wounds more slowly, and the reason is not fully understood. If cell fusion plays a central role in rapid repair, it becomes relevant to know whether that fusion capacity diminishes with age. This study did not investigate that directly, but it opens the question.

From fly to human?

The leap from fruit fly to human is large. But syncytia are not fly-specific: muscle cells, bone cells, and placental cells in mammals are also multi-nucleated. The principle of cell fusion as a repair mechanism is therefore evolutionarily conserved. Whether it is equally active in human wound healing, and whether it can be influenced, are questions for future research.

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