MST1 mediates neuronal loss and cognitive deficits: A novel therapeutic target for Alzheimer’s disease

Alzheimer's disease (AD) is the most prevalent form of dementia in the old adult and characterized by progressive cognitive decline and neuronal damage. The mammalian Ste20-like kinase1/2 (MST1/2) is a core component in Hippo signaling, which regulates neural stem cell proliferation, neuronal death and neuroinflammation. However, whether MST1/2 is involved in the occurrence and development of AD remains unknown. In this study we reported that the activity of MST1 was increased with Aβ accumulation in the hippocampus of 5xFAD mice. Overexpression of MST1 induced AD-like phenotype in normal mice and accelerated cognitive decline, synaptic plasticity damage and neuronal apoptosis in 2-month-old 5xFAD mice, but did not significantly affect Aβ levels. Mechanistically, MST1 associated with p53 and promoted neuronal apoptosis by phosphorylation and activation of p53, while p53 knockout largely reversed MST1-induced AD-like cognitive deficits. Importantly, either genetic knockdown or chemical inactivation of MST1 could significantly improve cognitive deficits and neuronal apoptosis in 7-month-old 5xFAD mice. Our results support the idea that MST1-mediated neuronal apoptosis is an essential mechanism of cognitive deficits and neuronal loss for AD, and manipulating the MST1 activity as a potential strategy will shed light on clinical treatment for AD or other diseases caused by neuronal injury.