Quantifying microenvironmental changes in the developing brain in response to acute and chronic metabolic disrupters

Abstract

Neurologic diseases are responsible for nearly one-third of all deaths and disability life-adjusted years, many with no effective treatments or cures. Treating the diseased brain is challenging physically, biologically, and clinically: the brain has multiple unique barriers to therapeutics, neurologic disease processes are highly multiplexed and variable, and the presence of pre-existing co-morbidities or prior neurologic conditions changes the disease landscape, complicating or impeding treatment efforts. In this work, we touch on all three challenges. We focus on metabolic disruptions in the form of mitochondrial dysfunction, which is implicated in nearly every neurologic disease and is shown to be a mediator of risk and susceptibility. We use organotypic whole-hemisphere (OWH) brain slice cultures to quantify how mitochondrial dysfunction alters the physical and biological microenvironments of the brain. First, we develop an OWH slice model of mitochondrial dysfunction using the canonical inhibitor rotenone (ROT). We observe region-, dose-, and time-dependent microenvironmental changes that mirror in vivo models. We also show how the extracellular microenvironment, a critical therapeutic barrier, is altered by mitochondrial dysfunction. Next, we characterize how mitochondrial dysfunction from ROT exposure modulates susceptibility to stroke-like injury using an oxygen-glucose deprivation (OGD) model, an effect which has not been previously investigated in vitro. Here, we demonstrate that timing of metabolic disruption relative to the OGD insult worsens tissue recovery. Gene expression analysis and imaging reveal a connection between mitochondrial state and inflammatory responses as one driver for metabolic-related effects on OGD recovery. Our findings highlight a role of pre-existing metabolic deficits in neurological injury and recovery, capture changes in microenvironment features that can impact therapeutic delivery and enable pre-clinical screening platforms that better represent the clinical scenario for patients seeking treatment for neurologic disease.