Plant stress hormone phaseic acid (PA), a major catabolite of abscisic acid (ABA), plays important roles in higher plants against a variety of environmental stresses, such as cold, drought, heat exposure, salinity. However, whether animals use this type of molecules for stress response remains an interesting question.  In particular, the presence and function of PA and its derivatives in animal brains are not known. The research led by Professor Shengtao Hou in the Department of Biology and Brain Research Center discovered the presence of plant naturally occurring (-)-PA in the brains mouse and rat. These studies are published in the recent issue of Journal of Biological Chemistry, a premier life science journal and one of the 68 Nature Index journals.

The work was in collaboration with Professor Suzanne Abrams’s team who is a world expert on ABA-related phytohormones in the Plant Biotechnology Institute in the National Research Council of Canada,  Together their experimental data showed that (-)-PA is expressed in the cerebral blood vessels and choroid plexus and functions to reversibly and transiently inhibit a major brain neuron receptor called NMDA receptors which are responsible for neuronal injury during hypoxia caused by stroke. Importantly, their studies demonstrated that naturally occurring PA in the brain may serve as an endogenous protector for neurons.

This is the first report of (-)-PA presence in rodent brains and revealed a previously unknown role of PA serving as an endogenous mechanism of neuroprotection in ischemic brain, and suggest that (-)-PA or its analogous can be developed as a powerful agent for neuroprotection against stroke.

Prof. Hou’s research is supported by grants from the National Natural Science Foundation, National Key Laboratory of Neuroscience and Shenzhen Municipal Government Science and Innovation Committee.