Arner, J. | Search bioRxiv

bioRxiv2024

The glucocorticoid response element near the sphingosine-1-phopshate receptor 3 gene mitigates inflammatory processes and maladaptive behavior in females and stressed males

It is well established that glucocorticoid receptors (GRs) bind DNA, regulate gene expression, reduce inflammatory processes, and modulate behavior. However, the precise loci bound by GRs that are necessary for these effects are not fully understood. Here, we deleted the GR binding site near the sphingosine-1-phospate receptor 3 gene using a CRISPR/Cas9 approach (S1PR3GR-/GR- rats). Defeated S1PR3GR-/GR- males displayed increased inflammatory markers and social anxiety-like behavior. Similar effects were observed in non-stressed females, indicating a greater dependence for GR-induced S1PR3 in females. Coherent neural activity between the locus coeruleus (LC) and medial prefrontal cortex (mPFC) was increased in S1PR3GR-/GR- males following 7 defeats. Chemogenetically inhibiting mPFC-projecting LC neurons during defeat increased subsequent social interaction in wild-type and S1PR3GR-/GR- males. Together, these findings demonstrate that GR-induced S1PR3 promotes resilience by mitigating stress-induced inflammatory processes and LC-mPFC coherence. One Sentence SummaryGlucocorticoid receptor-induced expression of sphingosine-1- phosphate receptor 3 reduces social anxiety-like behavior by mitigating stress-induced inflammatory processes and coherent neural activity between the locus coeruleus and medial prefrontal cortex.

neuroscience↗

bioRxiv2021

Activity-regulated cytoskeleton-associated protein (Arc/Arg3.1)-mediated plasticity in the paraventricular thalamic nucleus promotes a fundamental adaptation to stress

BACKGROUNDHabituation is defined as a progressive decline in response to repeated exposure to a familiar and predictable stimulus and is highly conserved across species. Disrupted habituation is a signature of post-traumatic stress disorder (PTSD). In rodents, habituation is observed in neural, neuroendocrine and behavioral responses to repeated exposure to the predictable and moderately intense stress or restraint. We previously demonstrated that lesions to the posterior division of the paraventricular thalamic nucleus (pPVT) impairs habituation. However, the underlying molecular mechanisms and specific neural connections among the pPVT and other brain regions that underlie habituation are unknown. METHODSBehavioral and neuroendocrine habituation was assessed in adult male Sprague-Dawley restraints using the repeated restraint paradigm. Pan neuronal and Cre-dependent Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) were used to chemogenetically inhibit the pPVT and the subpopulation of pPVT neurons that project to the medial prefrontal cortex (mPFC), respectively. Activity-regulated cytoskeleton-associated protein (Arc) expression was knocked down in the pPVT using siRNA directed towards Arc. Golgi staining was used to assess structural plasticity of pPVT neurons. Local field potential recordings were used to assess coherent neural activity between the pPVT and mPFC. The attentional set-shifting task was used to assess mPFC-dependent behavior. RESULTSHere, we show that Arc promotes habituation by increasing stress-induced spinogenesis in the pPVT, increasing coherent neural activity with the mPFC, and improving mPFC-mediated cognitive flexibility. CONCLUSIONOur results demonstrate that Arc induction in the pPVT regulates habituation to repeated restraint and mPFC function. One Sentence SummaryWe demonstrate that Arc in the posterior division of the paraventricular thalamic nucleus promotes habituation to repeated stress by increasing dendritic spines.

neuroscience↗