Mitochondrial pyruvate transport regulates presynaptic metabolism and neurotransmission
Abstract
Glucose has long been considered the primary fuel source for the brain. However, glucose levels fluctuate in the brain during sleep or circuit activity, posing significant metabolic stress. Here, we demonstrate that the mammalian brain utilizes pyruvate as a fuel source, and pyruvate can support neuronal viability in the absence of glucose. Nerve terminals are sites of metabolic vulnerability, and we show that mitochondrial pyruvate uptake is a critical step in oxidative ATP production in hippocampal terminals. We find that the mitochondrial pyruvate carrier is post-translationally modified by lysine acetylation which in turn modulates mitochondrial pyruvate uptake. Our data reveal that the mitochondrial pyruvate carrier regulates distinct steps in neurotransmission, namely, the spatiotemporal pattern of synaptic vesicle release and the efficiency of vesicle retrieval, functions that have profound implications for synaptic plasticity. In summary, we identify pyruvate as a potent neuronal fuel and mitochondrial pyruvate uptake as a critical node for the metabolic control of neurotransmission in hippocampal terminals.
Anupama Tiwari, Jongyun Myeong, Arsalan Hashemiaghdam, Marion I. Stunault, Hao Zhang, Xianfeng Niu, Marissa A. Laramie, Jasmin Sponagel, Leah Shriver, Gary J. Patti, Vitaly A. Klyachko and Ghazaleh Ashrafi
Correspondence: ghazaleh@wustl.edu
https://doi.org/10.5061/dryad.z8w9ghxnq
Description of method
All the recorded movies from synapses expressing pHluroin.
- Tyrode_Lactate_Pyruvate
36 files: each file include multi synapse movies (37x37xtimeframe)
- Tyrode_Lactate_Pyruvate_UK5099
9 files: each file include multi synapse movies (37x37xtimeframe)
Preprocessing:
VGlut1-pHluorin- release event detection and localization at subpixel resolution were performed using MATLAB and the uTrack software package, which was kindly made available by Dr Gaudenz Danuser’s lab. Localization precision was determined directly from least-squares Gaussian fits of individual events.
Event detection using ROI thresholding:
To determine synapse locations, the stack of all 4,000 frames in each movie was summed to create a combined image, and localizations of individual synapses were defined as local peaks in the combined image using ImageJ. Whole-synapse VGlut1-pHluorin intensity was measured over a 0.95 mm diameter circle (11 pixels) region of interest (ROI) centered on each bouton. A threshold on the ROI intensity was set at 0.15 dF/F. Only ROIs with a peak amplitude greater than 2 standard deviations for the previous 1 s were accepted. Finally, instantaneous slopes of ROI fluorescence changes were calculated frame-by-frame, and detection threshold was set at 0.1 a.u./frame. An event was accepted only when all three criteria were met: the ROI intensity, slope, and 2 standard deviations criteria.
Description of data and file structure
Each experimental condition corresponds to a different folder. Inside each folder, one file (.m extension) corresponds to a different coverslip named after the recording date and Data number. Inside each .m file, there is a MATLAB cell array where each item corresponds to a movie (uint16) recorded from an individual synapse while the stimulation protocol is applied.
Sharing/Access information
please visit the following github repository, pHluorin directory:
https://github.com/JongyunMyeong85/mitochondrial-pyruvate-carrier-MPC-.git