Herrera, I. | Search bioRxiv

bioRxiv2025

Amphetamine in Adolescence Induces a Sex-Specific Mesolimbic Dopamine Phenotype in the Adult Prefrontal Cortex

Drugs of abuse in adolescence impact brain maturation and increase psychiatric risk, with differences in sensitivity between males and females. Amphetamine in adolescent male, but not female mice, causes dopamine axons intended to innervate the nucleus accumbens and to grow ectopically to the prefrontal cortex (PFC). This is mediated by drug-induced downregulation of the Netrin-1 receptor DCC. How off-target dopamine axons function in the adult PFC remains to be determined. Here we report that males and females show place preference for amphetamine in adolescence. However, only in males, amphetamine increases PFC dopamine transporter expression in adulthood: leading to aberrant baseline dopamine transients, faster dopamine release, and exaggerated responses to acute methylphenidate. Upregulation of DCC in adolescence, using CRISPRa, prevents all these changes. Mesolimbic dopamine axons rerouted to the PFC in adolescence retain anatomical and functional phenotypes of their intended target, rendering males enduringly vulnerable to the harmful effects of drugs of abuse.

neuroscience↗

bioRxiv2021

Role of type I interferon signaling and microglia in the abnormal long term potentiation and object place recognition deficits of male mice with a mutation of the Tuberous Sclerosis 2 gene

Tuberous Sclerosis Complex (TSC) is a genetic disorder associated with high rates of intellectual disability and autism. Although previous studies focused on the role of neuronal deficits in the memory phenotypes of rodent models of TSC, the results presented here demonstrate a role for microglia in these deficits. Mice with a heterozygous null mutation of the Tsc2 gene (Tsc2+/-), show deficits in hippocampal dependent tasks, as well as abnormal long-term potentiation (LTP) in the hippocampal CA1 region. Here, we show that microglia and type I interferon signaling (IFN1) have a key role in the object place recognition (OPR; a hippocampal dependent task) deficits and abnormal LTP of Tsc2+/- male mice. Unexpectedly, we demonstrate that male, but not female, Tsc2+/- mice showed OPR deficits. Importantly, these deficits can be rescued by depletion of microglia, as well as by a genetic manipulation of a signaling pathway known to modulate microglia function (interferon-alpha/beta receptor alpha chain null mutation). In addition to rescuing the OPR deficits, depletion of microglia also reversed the abnormal LTP of the Tsc2+/- mice. Altogether, our results suggest that altered IFN1 signaling in microglia cause the abnormal LTP and OPR deficits of male Tsc2+/- mice.

neuroscience↗