Cells are well known to shed contents as part of remodeling during development. Now, the lab of Jeremy Nance at New York University School of Medicine describes a new remodeling process, termed “intercellular cannibalism,” that occurs during development of the nematode worm C. elegans. Primordial germ cells (PGCs) give rise to the reproductive cells (gametes) in animals. Dr. Nance’s research shows that PGCs in the worm discard nearly half their cellular contents, including most of their mitochondria, through this process. These PGCs produce large lobes that are engulfed by the neighboring endodermal cells (ECs); ECs go on to form the gut. Once the lobes are surrounded by the ECs, the ECs actively cut them off the PGCs and then digest them. In this way, the PGCs shed themselves of many mitochondria and get much smaller, and the ECs recycle the cellular material. This may be a method for the PGCs to protect the genome from mutations for future generations. Mitochondria produce high levels of reactive oxygen species that can cause DNA mutations, and such mutations in the germ line could lead to problems in the worms’ offspring. Interestingly, the relationship between PGCs and ECs is conserved in mammals in as much as the cells migrate together during development. The mechanisms underlying intercellular cannibalism may also be relevant to remodeling of synapses in the mammalian central nervous system. This work was supported in part by NYSTEM contract C029561 to Dr. Nance.
Abdu Y, Maniscalco C, Heddleston JM, Chew TL, Nance J. Developmentally programmed germ cell remodelling by endodermal cell cannibalism. Nature Cell Biology. 2016 Dec: 18(12):1302-1310.