Pericyte KATP channel hyperactivity redistributes cortical blood flow

Background: Cerebral hemodynamic dysfunction accelerates brain aging by impairing microcirculatory reactivity, leading to uneven perfusion and cognitive decline. Small vessel diseases (SVDs) like CADASIL, the most common genetic form driven by NOTCH3 mutations, disrupt brain circulation yet still lack effective treatments. In this context and despite high NOTCH3 expression, pericytes remain understudied. The ATP-sensitive K+ (KATP) channel couples cellular excitability to metabolic state and is highly expressed in capillary pericytes, where it supports activity-dependent cerebral blood flow (CBF). Pericytes in the arteriole-capillary transition (ACT) zone exhibit rapid contractile responses and orchestrate blood flow at capillary junctions, making them critical for microcirculatory control. We hypothesize that hyperactive KATP channels in ACT zone pericytes result in CBF redistribution driving SVD pathology. Objective: To investigate pericyte involvement in SVD, we assessed vasoreactivity, cerebral blood flow distribution, and examined how metabolic dysfunction correlates with impaired pericyte contractility and vascular regulation. Methods: We utilized a well-established SVD mouse model overexpressing the TgNotch3R169C mutation. Spatial transcriptomics were performed on isolated microvasculature and cortical brain slices to characterize gene expression patterns. We employed acute cranial window implantation combined with two photon laser scanning microscopy to investigate changes in microvascular diameter, tone, and KATP channel activity in vivo. Ex vivo assays in isolated and pressurized microvasculature include membrane potential recordings, pressure myography, and patch-clamp electrophysiology, with KATP pharmaceutical interrogation. We completed in silico vascular modeling to query impacts of KATP channel hyperactivity on perfusion throughout the cortex and used three photon imaging to measure red blood cell flux throughout different layers in the cortex. Results: In vivo and ex vivo studies demonstrated a 50% reduction in pressure-induced constriction in the SVD ACT zone. Pericytes were markedly hyperpolarized (-51 mV vs. -32 mV in controls), and spatial transcriptomics showed downregulation of ATP synthesis genes. Pressure myography and cranial window imaging demonstrated blunted dilation to the KATP channel agonist pinacidil (17% vs. 44%) and exaggerated constriction to the antagonist glibenclamide (28% vs. 10%). Patch-clamp confirmed elevated basal KATP currents sensitive to glibenclamide. Computational modeling predicted increased flow in superficial cortical layers at the expense of layer V, which was validated by three-photon imaging showing a 50% reduction in RBC flux in layer V (approximately 600 μm deep) of SVD mice. Conclusion: We identify a previously unrecognized mechanism of CBF dysregulation: basal KATP channel hyperactivation in ACT zone pericytes. Because KATP activity reflects metabolic state, metabolic dysfunction likely underlies pericyte contractile failure and perfusion heterogeneity. Targeting metabolic integrity to reduce KATP channel activity may normalize pericyte function and offer a therapeutic strategy for SVD and related dementias. This research was funded by NHLBI: DAJ F31HL170645, FD R01HL136636, NINDS: FD RF1/R01NS129022, R01/RF1NS140137, cureCADASIL and the BRENDA Leducq Network. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.