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Authors & Affiliations
Moshe Willner, Briana K. Chen, Rebecca L. Noel, Alec J. Batts, Alessia Mastrodonato, Michelle Jin, Robin Ji, Louise C. Matthews, Fotis Tsitsos, Daniella Jimenez, Samantha L. Gorman, Clay O. Lacefield, Elisa E. Konofagou, Christine A. Denny
Abstract
Major depressive disorder (MDD) is a leading cause of disability worldwide, but its pathogenesis is unclear. Mounting evidence implicates the loss of blood-brain barrier (BBB) integrity as it exposes the brain to harmful inflammatory mediators, antibodies, and serum proteins, but to date no pharmacotherapies specifically target the BBB. Focused ultrasound (FUS) is a non-invasive, neuromodulatory strategy that transiently opens the BBB (FUS-BBBO) when coupled with microbubbles. Here, we examine FUS-BBBO as an independent therapy in a mouse model of stress-induced depression. Briefly, adult male and female mice were administered a 3-shock contextual fear conditioning (CFC) paradigm. Twenty-four hours later, mice were given a sham or FUS-BBBO procedure targeted to the hippocampus. T1-weighted MRI validated targeting. Four days later, mice were re-exposed to the CFC context to assay freezing behavior. Depressive-like, anxiety-like, locomotor, perseverative, and hyponeophagia were measured on subsequent days. Brain tissue was immunostained for Claudin-5 (CLDN5), the most highly expressed tight junction protein in the BBB. We report that a single administration of FUS-BBBO reduces behavioral despair in male, but not female, mice. Staining results show that CLDN5 is significantly decreased following CFC, and this effect is rescued by FUS-BBBO administration. In addition, baseline CLDN5 expression is less in female mice when compared to male mice. These data indicate that FUS-BBBO can act as a novel antidepressant through CLDN5 remodeling.