ESCRT III repairs nuclear envelope ruptures during cell migration to limit DNA damage and cell death

Abstract

In eukaryotic cells, the nuclear envelope separates the genomic DNA from the cytoplasmic space and regulates protein trafficking between the two compartments. This barrier is only transiently dissolved during mitosis. Here, we found that it also opened at high frequency in migrating mammalian cells during interphase, which allowed nuclear proteins to leak out and cytoplasmic proteins to leak in. This transient opening was caused by nuclear deformation and was rapidly repaired in an ESCRT (endosomal sorting complexes required for transport)-dependent manner. DNA double-strand breaks coincided with nuclear envelope opening events. As a consequence, survival of cells migrating through confining environments depended on efficient nuclear envelope and DNA repair machineries. Nuclear envelope opening in migrating leukocytes could have potentially important consequences for normal and pathological immune responses.

A Chemomechanical Model for Nuclear Morphology and Stresses during Cell Transendothelial Migration

“…Transmigration-induced rupture of the NE exposes the genomic DNA to normally cytoplasmic factors (Fig. 3 f), including nucleases, which could result in DNA damage, as observed in recent studies (12,13). Although cells in those studies were generally able to tolerate NE rupture and DNA damage, combined inhibition of ESCRT-III-mediated NE repair and DNA-damage repair pathways substantially increased the rate of cell death during transmigration (12,13), highlighting the importance of maintaining NE integrity during migration.…”

“…Although cells in those studies were generally able to tolerate NE rupture and DNA damage, combined inhibition of ESCRT-III-mediated NE repair and DNA-damage repair pathways substantially increased the rate of cell death during transmigration (12,13), highlighting the importance of maintaining NE integrity during migration. Importantly, some cells also exhibit DNA damage during transmigration through small constrictions even without NE rupture (12). In these cases, DNA damage could result from mechanical straining of the chromatin and/or from volume changes of the nucleus.…”

“…Recently it has been shown that rupture of the NE during cell migration through rigid constrictions can potentially lead to herniation of chromatin across the NE and breaking of DNA double strands (12,13). The rupture and blebs are often found at defective sites in the NE where the nuclear lamina signal was weak or absent (13).…”

“…On the other hand, since the nucleus houses the genetic machinery of the cell, changes in the nuclear morphology and positioning within the cytoplasm during migration can influence the phenotypic profile of the cell (5,11). For instance, it has been recently shown that in addition to the ability of cells to dramatically squeeze their nuclei to pass through small constrictions, cells utilize components of the endosomal sorting complexes required for transport (ESCRT) machinery to repair the concomitant damage to their nuclear envelope (NE) and DNA that occur during confined migration (12,13).…”

Macromolecular crowding effect is critical for maintaining SIRT1's nuclear localization in cancer cells

“…Two recent studies demonstrate that cell migration through confining spaces, as often encountered during the invasion of tumor cells into tight interstitial spaces within adjacent tissue, induces NE ruptures and uncontrolled exchange of nucleocytoplasmic content and triggers DNA damage response. 53,54 It will be intriguing to investigate whether SIRT1 transiently leaks out during this process and thus contributes to downstream response and tumor progression.…”