Calling out the cell undertakers

Millions of cells die naturally each day in a person. Scientists have now discovered that these dying cells send out a chemical signal to attract other cells that specialize in disposing of cellular corpses.

Over the past few years, biologists have begun to understand how macrophages and other cells recognize dying cells. For example, a cell about to die sprouts what scientists refer to as eat-me signals, which tell a macrophage to consume the cell before it falls apart and triggers inflammation (SN: 9/28/02, p. 202: Get Rid of the Bodies).

But what if there is no macrophage close at hand to a dying cell? No problem, say Sebastian Wesselborg of the University of Tübingen in Germany and his colleagues. In the June 13 Cell, they report that dying cells from monkeys, mice, and people secrete a molecule called lysophosphatidylcholine. Previous research showed that the chemical attracts macrophages and other immune cells that may be some distance away. This lure ensures that dying cells are removed efficiently, Wesselborg’s group concludes.

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