Mechanisms of compartmentalized ROS sensing in the brain

The National Institute of Neurological Disorders and Stroke awarded The General Hospital Corporation (doing business as Massachusetts General Hospital) $1.854 million on September 1, 2026, under the Extramural Research Programs in the Neurosciences and Neurological Disorders program (CFDA 93.853).

The award funds research into compartmentalized reactive oxygen species (ROS) sensing in the brain, specifically investigating how neurons balance mitochondrial energy production with ROS control. The project uses chemical proteomics, genome-wide CRISPR screens, and untargeted metabolomics to characterize how neurotransmission regulates VPS35—a component of the retromer trafficking complex that senses cytosolic ROS—and how mitochondrial translation is controlled across the soma, axon, and bouton of highly compartmentalized neurons. The research explores mitochondrial translation as a critical mechanism for reducing mitochondrial ROS generation in neurons.

Performance runs from September 1, 2026, through August 31, 2029, at Massachusetts General Hospital's Research Management Division in Boston, Massachusetts. The assistance type is a Project Grant.

Abstract

High ATP production through oxidative phosphorylation (OXPHOS) in the mitochondria is required to meet the energy demands of neuronal activity. Reactive oxygen species (ROS) are a group of reactive metabolites and a byproduct of normal OXPHOS function. At high concentrations, they can destroy nucleic acids and inactivate proteins. Thus, neurons must balance mitochondrial energy production with ROS control, but how they do so remains incompletely understood. To answer these questions, we undertook a cysteine-focused base editing screen to identify cysteines that are required for the cellular response to ROS. This approach identified two cysteines within VPS35, a component of the retromer trafficking complex, that sense cytosolic ROS. When reduced, VPS35 can shuttle plasma membrane proteins to support mitochondrial translation. Oxidation of these cysteines shuts down mitochondrial translation and decreases ROS. Thus, mitochondrial translation is a central lever within the cell to control ROS generation. With this discovery, many questions remain. IT is not known how a neuron balances ATP generation with an anti-ROS response that targets mitochondrial translation, nor how the regulation of mitochondrial translation varies across diverse mitochondrial pools with different metabolic needs. We hypothesize that inhibition of mitochondrial translation is a critical mechanism for reducing mitochondrial ROS generation in neurons. We will characterize how neurotransmission regulates VPS35 and how mitochondrial translation is controlled across the soma, axon, and bouton of highly compartmentalized neurons. The research proposed herein takes full advantage of a series of recently conceived methods: chemical proteomics, genome-wide crispr screens and untargeted metabolomics. We will use these in an integrated manner to effectively dissect how mitochondrial translation underlies cellular ROS in neuronal biology.