Anxiety-Associated Behaviors Following Ablation of <i>Miro1</i> from Cortical Excitatory Neurons

Autism spectrum disorder, schizophrenia, and bipolar disorder are neuropsychiatric conditions that manifest early in life with a wide range of phenotypes, including repetitive behavior, agitation, and anxiety ( American Psychological Association, 2013). While the etiology of these disorders is incompletely understood, recent data implicate a role for mitochondrial dysfunction ( Norkett et al., 2017; Khaliulin et al., 2025). Mitochondria translocate to intracellular compartments to support energetics and free-radical buffering; failure to achieve this localization results in cellular dysfunction ( Picard et al., 2016). Mitochondrial Rho-GTPase 1 (<i>Miro1</i>) resides on the outer mitochondrial membrane and facilitates microtubule-mediated mitochondrial motility ( Fransson et al., 2003). The loss of <i>MIRO1</i> is reported to contribute to the onset/progression of neurodegenerative diseases, including amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease ( Kay et al., 2018). We have hypothesized that MIRO1 also has a role in nervous system development ( Lin-Hendel et al., 2016). To test this, we ablated <i>Miro1</i> from cortical excitatory progenitors by crossing floxed <i>Miro1</i> mice with <i>Emx1-Cre</i> mice and studied mice of both sex. We found that mitochondrial mislocalization in migrating excitatory neurons was associated with reduced brain weight, decreased cortical volume, and subtle cortical disorganization. Adult <i>Miro1</i> conditional mutants exhibit agitative-like behaviors, including decreased nesting and abnormal home cage activity. The mice exhibited anxiety-like behavior and avoided confined spaces, features that have been linked to several human behavioral disorders. Our data link MIRO1 function with mitochondrial dynamics in the pathogenesis of several neuropsychiatric disorders and implicate intracellular mitochondrial dynamics to several anxiety-like behaviors.