Figure 1. The role of HSC Cx43 in ROS scavenging by the hematopoietic microenvironment. (A) Following 5-FU administration, normal HSC are able to eliminate a significant part of the excess of ROS through Cx43-mediated channels between HSC and BM stromal cells. (B) ROS levels accumulate in Cx43-deficient HSC and activate the p38 MAPK-p16ink4a pathway, resulting in HSC apoptosis and senescence.