皮膚は傷を記憶する

Inflammatory memory sensitizes skin epithelial stem cells to tissue damage.  Nature 550: 475–480.
The skin barrier is the body’s first line of defence against environmental assaults, and is maintained by epithelial stem cells (EpSCs).  Despite the vulnerability of EpSCs to inflammatory pressures, neither the primary response to inflammation nor its enduring consequences are well understood.  Here we report a prolonged memory to acute inflammation that enables mouse EpSCs to hasten barrier restoration after subsequent tissue damage.  This functional adaptation does not require skin-resident macrophages or T cells.  Instead, EpSCs maintain chromosomal accessibility at key stress response genes that are activated by the primary stimulus.  Upon a secondary challenge, genes governed by these domains are transcribed rapidly.  Fuelling this memory is Aim2, which encodes an activator of the inflammasome.  The absence of AIM2 or its downstream effectors, caspase-1 and interleukin-1β, erases the ability of EpSCs to recollect inflammation.  Although EpSCs benefit from inflammatory tuning by heightening their responsiveness to subsequent stressors, this enhanced sensitivity probably increases their susceptibility to autoimmune and hyperproliferative disorders, including cancer.

損傷等によって一度急性の炎症に晒された上皮組織では、epithelial stem cellsにこれが記憶されていて、またもう一度損傷が生じた場合には修復に対してより早いレスポンスをすることができる。で、このメカニズムはこちらのハイライト記事にある図の通り。ATAC-seqっていうchromatin accessibilityをマッピングする方法を使ってるけど、これなかなかスゴイね。
まぁでもやはり、こういう風にstem cellのセンシティビティを上げておくということは、同時に危険性も孕むということになるか。