DESCRIPTION:

To examine forebrain transcriptomic changes that might elucidate mechanisms of withdrawal, delayed development, and any long-term behavior changes, we generated transcriptomic signatures following our “3-trimester” exposure model (3-Tri). In addition, we also examined transcriptomes from animals that received opioids only during the gestational period (PND1) or only during the last trimester from PND 1–14 (PND 14). We sought to determine whether transcriptomic signatures vary based on the window of exposure, perhaps contributing to the discrepancies in the literature regarding acute and long-term outcomes. Brains were dissected from PND 1 pups 6 h after discovery. Brains were dissected from post-natal exposure only (PND 14) or 3-trimester exposure (3-tri) 6 h after the last morphine or saline injection. The number of animals per group was similar (N = 5–7 animals, male and female C57Bl/6NTac mice), and the quality controls, library construction and sequence parameters were also identical across all groups. Libraries were sequenced on a NovaSeq 6000 at a depth of 30 million total reads/sample using paired-end sequencing of 150 base pairs (PE150), to a depth of 30 million total reads/sample. Reads were then mapped to the mouse reference genome (Mus Musculus, GRCm38/mm10) using HISAT2 (version 2.2.1), and duplicated fragments were removed using Picard MarkDuplicates. Differential expression analysis between two conditions (e.g., Morphine and Saline) was performed in R (version 4.1.1) with DESeq2 (v1.32.0) package. Genes were assigned by the authors as differentially expressed if the (adjusted) (nominal) p-value < 0.05. All genes/scores are presented here.

LABEL:

DEG female mouse forebrain PND1 morphine vs saline_pvalue

SCORE TYPE:

P-Value

THRESHOLD:

<= 0.5

GENES IN THRESHOLD:

14936

DATE ADDED:

2025-01-02

DATE UPDATED:

2025-01-02

SPECIES:

AUTHORS:

Amelia D Dunn, Shivon A Robinson, Chiso Nwokafor, Molly Estill, Julia Ferrante, Li Shen, Crystal O Lemchi, Jordi Creus-Muncunill, Angie Ramirez, Juliet Mengaziol, Julia K Brynildsen, Mark Leggas, Jamie Horn, Michelle E Ehrlich, Julie A Blendy 

TITLE:

Molecular and long-term behavioral consequences of neonatal opioid exposure and withdrawal in mice

JOURNAL:

Frontiers in Behavioral Neuroscience Jun 2023, Vol 17, pp.

ABSTRACT:

Introduction: Infants exposed to opioids in utero are at high risk of exhibiting Neonatal Opioid Withdrawal Syndrome (NOWS), a combination of somatic withdrawal symptoms including high pitched crying, sleeplessness, irritability, gastrointestinal distress, and in the worst cases, seizures. The heterogeneity of in utero opioid exposure, particularly exposure to polypharmacy, makes it difficult to investigate the underlying molecular mechanisms that could inform early diagnosis and treatment of NOWS, and challenging to investigate consequences later in life. Methods: To address these issues, we developed a mouse model of NOWS that includes gestational and post-natal morphine exposure that encompasses the developmental equivalent of all three human trimesters and assessed both behavior and transcriptome alterations. Results: Opioid exposure throughout all three human equivalent trimesters delayed developmental milestones and produced acute withdrawal phenotypes in mice reminiscent of those observed in infants. We also uncovered different patterns of gene expression depending on the duration and timing of opioid exposure (3-trimesters, in utero only, or the last trimester equivalent only). Opioid exposure and subsequent withdrawal affected social behavior and sleep in adulthood in a sex-dependent manner but did not affect adult behaviors related to anxiety, depression, or opioid response. Discussion: Despite marked withdrawal and delays in development, long-term deficits in behaviors typically associated with substance use disorders were modest. Remarkably, transcriptomic analysis revealed an enrichment for genes with altered expression in published datasets for Autism Spectrum Disorders, which correlate well with the deficits in social affiliation seen in our model. The number of differentially expressed genes between the NOWS and saline groups varied markedly based on exposure protocol and sex, but common pathways included synapse development, the GABAergic and myelin systems, and mitochondrial function. PUBMED: 37424750
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