CACNA1C is a risk gene for multiple psychiatric disorders and the CaV1.2 protein it encodes is a potential target for their treatment. It is known that alternative start exon usage and splicing of CACNA1C RNA results in multiple transcript isoforms. However, the identity of full-length isoforms, and their relative abundance between tissues, remains unknown. Such information is important for understanding the molecular mechanisms of illness associations and to advance the potential for CaV1.2 isoform-selective drugs. In this study we compared full-length isoforms expressed in human brain with those expressed in heart and aorta using PCR-targeted long-read nanopore amplicon sequencing. We also performed 5’-RACE to profile which CACNA1C transcription start exons are used. CACNA1C RNA splicing revealed distinct tissue-enriched isoforms in brain, heart and aorta, with the results corroborated by publicly available short-read RNA-seq data. For example, splicing of mutually exclusive exons 21 and 22 differentiated isoforms expressed in the brain from those in the heart and aorta. 5’-RACE identified a novel start exon, exon 1d, which was detected in brain and aorta but not heart, and which predicts channels with a truncated N-terminus. The full-length isoforms identified here, from both the previously known start exons and the novel start exon, are likely to impact on the function and the pharmacology of the encoded CaV1.2 channel. Identification of brain-enriched isoforms provides the possibility of designing drugs preferentially targeting CaV1.2 for psychiatric indications.
Early-childhood temperament is associated with later mental health. Temperament continues to develop throughout the first years of life, and a single assessment cannot capture its trajectory. Whether departures from an individual’s developmental trajectory carry psychiatric risk remains unknown. Using data from more than 50,000 children in the Norwegian Mother, Father and Child Cohort Study, we modeled longitudinal temperament at 1.5, 3, and 5 years of age with the FEMA-Long mixed-effects framework. We then quantified each child’s departures from their predicted trajectories. Multivariate analysis revealed two transdiagnostic dimensions linking trajectory departures to psychiatric diagnoses across childhood and adolescence. Higher scores on the first dimension were associated with an increased hazard of subsequent ADHD diagnosis (hazard ratio = 1.54), and higher scores on the second with an increased hazard of Asperger syndrome (hazard ratio = 1.64). To examine the genetic basis of these associations, we performed longitudinal GWAS of temperament and conjunctional FDR analysis to detect loci shared with the associated diagnoses. The effects of these loci changed across early childhood, with some strengthening and others attenuating with age. These findings show that departures from predicted temperament trajectories reflect transdiagnostic psychiatric risk with a shared genetic basis. Longitudinal, trajectory-based monitoring could help identify children at elevated psychiatric risk.
Stressful and emotionally salient stimuli often trigger heightened wakefulness that can predispose to sleep disorders such as insomnia. The bed nucleus of the stria terminalis (BNST), a center for emotional information processing and anxiety-related behaviors, contains diverse neuropeptide-enriched neuronal subpopulations that may respond to and drive opposing emotional states. Although recently implicated in arousal regulation, the mechanisms by which BNST neuronal subpopulations control sleep-wake states remain unclear. Here, we show that optogenetic activation of corticotropin-releasing hormone (CRH)-expressing neurons, but not cholecystokinin- or somatostatin-expressing neurons, in the BNST triggers a rapid shift from non-rapid eye movement sleep to wakefulness in male mice. BNST CRH neurons are active during both wakefulness and rapid eye movement (REM) sleep, and their optogenetic activation also triggers wakefulness from REM sleep. Chemogenetic activation of BNST CRH neurons significantly increases the amount and alpha (8-13 Hz) power of wakefulness, whereas their inhibition decreases wakefulness. Moreover, inhibition of BNST CRH neurons alleviates stress-induced heightened wakefulness. These results identify BNST CRH neurons as key regulators of wakefulness under physiological and stressful conditions and suggest them as potential targets for stress-induced heightened wakefulness and insomnia.
Psychedelics modulate emotion and cognition, yet the underlying mechanisms remain unclear. Given the ability of psychedelics to induce visual hallucinations, we employed the looming model-a visual threat assay that combines visual stimulation with innate fear-to investigate the effects of psychedelics. Unexpectedly, 4-acetoxy-N,N-dimethyltryptamine (4-AcO-DMT), a psychedelic compound that acts as a prodrug of psilocin and exhibits comparable central nervous system effects to psilocybin, significantly reduced looming-induced freezing behavior compared to R/S-MDMA, without eliciting overt hallucinogen-like effects under the current experimental conditions. This anti-fear effect was independent of β-arrestin 2 signaling and visual function, but associated with decreased innate fear emotion. We identified that 4-AcO-DMT activates CaMKIIα neurons in the prelimbic cortex (PrL) via 5-HT2A receptors, and the PrL CaMKIIα-MD CaMKIIα circuit mediates this response. Our findings reveal that despite being designed from a visual hallucination perspective, the looming model unexpectedly uncovers a robust anti-innate fear effect of psychedelics, providing new insights into their emotional modulation and therapeutic potential.
Adolescent depression is undergoing a rapid surge and has become a severe global public health challenge. However, current therapeutic approaches are limited and often accompanied by significant side effects primarily due to the elusive underlying mechanisms. The gut-brain axis has recently gained growing attention for its pivotal roles in neuropsychiatric disorders, particularly the tryptophan (Trp) metabolism by the microbiota. With the 16S rRNA gene sequencing, the abundance of Bacteroidetes, a microbiota phylum that includes several taxa involved in tryptophan metabolism and indole derivative production was significantly reduced in unmedicated adolescents with depression. The in-depth analysis showed that levels of key indole derivatives, including IAA, IPA and IAld, were markedly decreased in depressed patients; crucially, these reductions showed a significant negative correlation with depression severity scores. Consistent with the clinical findings, a similar decline in IAA, IPA, and IAld levels was observed in adolescent mice with depression induced by chronic restraint stress (CRS). Notably, depression-like behaviors in these mice were substantially ameliorated by a high-Trp diet (CRS + 1.19% Trp) and direct supplementation with indole derivatives. In a reciprocal experiment, a low-Trp diet (0.09% Trp) was found to de novo induce depressive behaviors in otherwise healthy mice. Morphological analysis of brain tissue uncovered another critical insight, the microglial cells in CRS mice exhibited hallmark features of overactivation. Remarkably, both the high-Trp diet and indole derivative supplementation exerted consistent protective effects, shown as restored microglial morphology and neurogenesis. Mechanistically, the indole derivatives were shown to activate AhR signaling, which in turn balanced the expression of anti-inflammatory factors (e.g., IL-10, TGF-β) and pro-inflammatory factors (e.g., IL-1β, CD68), thereby remodeling microglial morphology and promoting neurogenesis in hippocampus. A series of loss-of-function and gain-of-function experiments further confirmed AhR's essential role: the salutary effects of indole derivatives on anti-depression were substantially attenuated in AhR-/- mice; reciprocally, conditional microglia-specific overexpression of AhR in the hippocampus of CRS mice significantly ameliorated CRS-induced depressive-like changes, accompanied by suppression of microglial activation and upregulation of anti-inflammatory factors. Collectively, the present study revealed a previously unrecognized the microbiota-derived indole derivatives ameliorated CRS-induced adolescent depression via the AhR signaling pathway. These findings highlight that targeting the indole derivative-AhR signaling axis may represent a novel therapeutic strategy for adolescent depression, one with the potential to minimize side effects and address the unmet clinical needs of this vulnerable population.
