Vascular signaling plasticity reprograms neurovascular coupling pathways to precisely match energy delivery to neuronal metabolic needs

Abstract

Neuronal computation is metabolically expensive and relies on the timely delivery of energy substrates via tightly controlled blood flow to prevent energetic deficits. The range of mechanisms responsible for this coupling of neural activity to blood flow are collectively termed ‘neurovascular coupling’ (NVC). These NVC mechanisms are typically assumed to be invariant and the possibility that they may be plastic, allowing reshaping of energy delivery according to ever-shifting neuronal metabolic needs, has not been considered. We present evidence that neuronal activity resculpts blood flow control mechanisms inherent to the endothelium, which forms the inner lining of all blood vessels, through a process we refer to as vascular signalling plasticity (VSP). Using an environmental enrichment paradigm, we find that housing mice in an environment that increases input to the barrel cortex drives profound synaptic plasticity within this network. This is accompanied by a remarkable resculpting of local vascular reactivity, augmenting the efficacy of mechanisms that signal for an increase in blood flow. This increase in sensitivity manifests as an increase red blood cell flux to capillary stimulation with extracellular K+, which activates strong inward rectifier K+ (Kir2.1) channel-dependent capillary-to-arteriole electrical signalling to elicit hyperemia. To support this augmentation, we find that VSP induces a ~70% increase in the density of Kir2.1 channels in endothelial cells membranes which is underlain by transcriptional and translational changes in capillary ECs. Using an ex vivo capillary-arteriole preparation, we demonstrate that this increase in membrane Kir2.1 channels translates into a profound shift in the sensitivity of capillaries to K+ stimulation to evoke upstream arteriolar dilation. Together, these results suggest that increasing neuronal energy consumption leads to a profound potentiation of the retrograde hyperpolarization generated by the endothelium during activity, enhancing upstream dilation at the penetrating arteriole and augmenting blood delivery to match enhanced local needs. Our data thus recast the capillary bed as a plastic, brain-wide, neural activity sensing network that is modulated at the molecular level by local neural input. This allows fine-tuning of existing blood delivery mechanisms to meet continually fluctuating neural energy needs. VSP represents a novel facet of brain plasticity that may be utilised by various physiological processes and may be disrupted in aging and in the broad range of brain pathologies that have a vascular component. Support for this work was provided by the NIH National Institute on Aging and National Institute of Neurological Disorders and Stroke (1R01AG066645, 5R01NS115401 [PI: S. Sakadžić], and 1DP2NS121347-01, to T.A.L), the American Heart Association (Awards 17SDG33670237 and 19IPLOI34660108 to T.A.L) and an NIH S10 grant (S10 OD026698, to University of Maryland School of Medicine CIBR Core Confocal Facility). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.