MST1/2 inhibitor XMU-MP-1 alleviates the injury induced by ionizing radiation in haematopoietic and intestinal system.

The Hippo signalling pathway has been considered as potential therapeutic target in self-renewal and differentiation of stem and progenitor cells. Thus, mammalian Ste20-like kinase 1/2 (MST1/2) as the core serine-threonine kinases in the Hippo signalling pathway has been investigated for its role in immunological disease. However, little information of MST1/2 function in bone marrow suppression induced by ionizing radiation was fully investigated. Here, we reported that MST1/2 inhibitor XMU-MP-1 could rescue the impaired haematopoietic stem cells (HSCs) and progenitor cells (HPCs) function under oxidative stress condition. Also, XMU-MP-1 pretreatment markedly alleviated the small intestinal system injury caused by the total body irradiation 9 Gy and extended the average survival days of the mice exposed to the lethal dose radiation. Therefore, irradiation exposure causes the serious pathological changes of haematopoietic and intestinal system, and XMU-MP-1 could prevent the ROS production, the haematopoietic cells impairment and the intestinal injury. These detrimental effects may be associated with regulating NOX/ROS/P38MARK pathway by MST1/2.