(P27-029-23) Alpha-Tocotrienol: A Nutritional Regulator of Bcl-xL in Neurons

Objectives: B-cell lymphoma-extra large (Bcl-xL) is a mitochondrial anti-apoptotic protein. Bcl-xL is necessary for neurite outgrowth, synapse formation, and neuronal energy metabolism. In this study, we aim to develop nutritional strategies to regulate Bcl-xL in neurons that can be expanded to translational research. Alpha-tocotrienol (α-TCT), a form of vitamin E, crosses the blood-brain barrier and exhibits neuroprotection against neurotoxic stimuli. We hypothesize that Bcl-xL is an important target of α-TCT-mediated neuroprotection and neuronal development.

Methods: Primary hippocampal neurons were grown for 3 weeks in media with or without α-TCT. We changed pre-conditioned media once per week. We quantified intracellular α-TCT levels using HPLC-MS and evaluated neuronal energy metabolism by measuring intracellular ATP and oxygen consumption levels. We quantified mRNA and protein levels of Bcl-xL using qPCR and immunoblotting, respectively. We further quantified protein levels of delta-N-Bcl-xL, the post-translational cleavage product of Bcl-xL. We examined the number of neurite branches using Sholl analysis.

Results: Treatment with α-TCT increased intracellular α-TCT and ATP levels in primary hippocampal neurons. Hippocampal neurons without α-TCT treatment grew normally; however, neurons treated with α-TCT increased the number of neurite branches, indicating advanced neurite complexity. We also found that α-TCT treatment increased the abundance of Bcl-xL.

Conclusions: Our findings suggest that α-TCT may support the normal development of the brain, or prevent neuronal injury associated with mitochondrial dysfunction.

Funding Sources: RGC Program (University of Alabama); Crenshaw Research Fund (University of Alabama)