Activation of a synapse weakening pathway by human Val66 but not Met66 pro-brain-derived neurotrophic factor (proBDNF)

作者：Kailainathan Sumangali; Piers Thomas M; Yi Jee Hyun; Choi Seongmin; Fahey Mark S; Borger Eva; Gunn Moore Frank J; O'Neill Laurie; Lever Michael; Whitcomb Daniel J; Cho Kwangwook^*; Allen Shelley J^*

来源：Pharmacological Research, 2016, 104: 97-107.

DOI：10.1016/j.phrs.2015.12.008

• Pro-brain-derived neurotrophic factor (proBDNF)
• Val66Met polymorphism
• Long-term depression (LTD)
• Binding kinetics
• Neurotrophin receptors
• Chemical compounds studied in this article

This study describes a fundamental functional difference between the two main polymorphisms of the pro-form of brain-derived neurotrophic factor (proBDNF), providing an explanation as to why these forms have such different age-related neurological outcomes. Healthy young carriers of the Met66 form (present in similar to 30% Caucasians) have reduced hippocampal volume and impaired hippocampal-dependent memory function, yet the same polymorphic population shows enhanced cognitive recovery after traumatic brain injury, delayed cognitive dysfunction during aging, and lower risk of late-onset Alzheimer's disease (AD) compared to those with the more common Val66 polymorphism. To examine the differences between the protein polymorphisms in structure, kinetics of binding to proBDNF receptors and in vitro function, we generated purified cleavage-resistant human variants. Intriguingly, we found no statistical differences in those characteristics. As anticipated, exogenous application of proBDNF Val66 to rat hippocampal slices dysregulated synaptic plasticity, inhibiting long-term potentiation (LTP) and facilitating long-term depression (LTD). We subsequently observed that this occurred via the glycogen synthase kinase 313 (GSK3 beta) activation pathway. However, surprisingly, we found that Met66 had no such effects on either LTP or LTD. These novel findings suggest that, unlike Val66, the Met66 variant does not facilitate synapse weakening signaling, perhaps accounting for its protective effects with aging.

• 出版日期2016-2