Biology subjects

Danna, B. T.

Publications and source records attributed to Danna, B. T..

2 recordsLinked to original sources

bioRxiv2025

13C tracing in synaptosomes reveals that SGLT2 inhibition with dapagliflozin prevents metabolic deficits in the 5X-FAD model of Alzheimer's Disease

Metabolic dysfunction is linked to several forms of age-related neurodegeneration including Alzheimers Disease (AD), and targeting brain energy metabolism is an increasingly attractive mode of therapeutic intervention. However, commonly used in vitro methods to identify specific metabolic pathways of interest in preclinical models of neurodegenerative disease have considerable limitations. They are prone to subselection of sample material, unable to identify cell type-specific effects, or cannot identify metabolic defects upstream of mitochondria. Here we address these challenges by validating a method for stable isotope tracing with isolated synaptic nerve terminals, or synaptosomes. We further applied this approach to study glucose metabolism in synaptosomes isolated from the 5X-FAD mouse model of AD treated with the antidiabetic sodium-glucose linked transporter-2 (SGLT-2) inhibitor Dapagliflozin. Treatment with Dapagliflozin preserved steady-state levels of synaptosomal metabolites and enrichment from labeled glucose into citrate that was reduced in the 5X-FAD model. These changes correlated with trends towards improved spatial working memory but not amyloid burden. The results highlight the utility of stable isotope tracing in synaptosomes to identify precise sites of metabolic dysfunction and mechanisms of action for metabolic drug candidates in preclinical models of neurodegeneration.

biochemistry↗

bioRxiv2023

The BCKDK inhibitor BT2 is a chemical uncoupler that lowers mitochondrial ROS production and de novo lipogenesis

Elevated levels of branched chain amino acids (BCAAs) and branched-chain -ketoacids (BCKAs) are associated with cardiovascular and metabolic disease, but the molecular mechanisms underlying a putative causal relationship remain unclear. The branched-chain ketoacid dehydrogenase kinase (BCKDK) inhibitor BT2 is often used in preclinical models to increase BCAA oxidation and restore steady-state BCAA and BCKA levels. BT2 administration is protective in various rodent models of heart failure and metabolic disease, but confoundingly, targeted ablation of Bckdk in specific tissues does not reproduce the beneficial effects conferred by pharmacologic inhibition. Here we demonstrate that BT2, a lipophilic weak acid, can act as a mitochondrial uncoupler. Measurements of oxygen consumption, mitochondrial membrane potential, and patch-clamp electrophysiology show BT2 increases proton conductance across the mitochondrial inner membrane independently of its inhibitory effect on BCKDK. BT2 is roughly five-fold less potent than the prototypical uncoupler 2,4-dinitrophenol (DNP), and phenocopies DNP in lowering de novo lipogenesis and mitochondrial superoxide production. The data suggest the therapeutic efficacy of BT2 may be attributable to the well-documented effects of mitochondrial uncoupling in alleviating cardiovascular and metabolic disease.

biochemistry↗