Traumatic Stress-Induced Vulnerability to Addiction: Critical Role of the Dynorphin/Kappa Opioid Receptor System

The ultrasonic vocalization (USV) syllable profile during neonatal opioid withdrawal and a kappa opioid receptor component to increased USV emissions in female mice

RATIONALE

Opioid use during pregnancy can lead to negative infant health outcomes, including neonatal opioid withdrawal syndrome (NOWS). NOWS comprises gastrointestinal, autonomic nervous system, and neurological dysfunction that manifest during spontaneous withdrawal. Variability in NOWS severity necessitates a more individualized treatment approach. Ultrasonic vocalizations (USVs) in neonatal mice are emitted in isolation as a stress response and are increased during opioid withdrawal, thus modeling a negative affective state that can be utilized to test new treatments.

OBJECTIVES

We sought to identify the behavioral and USV profile, brainstem transcriptomic adaptations, and role of kappa opioid receptors in USVs during neonatal opioid withdrawal.

METHODS

We employed a third trimester-approximate opioid exposure model, where neonatal inbred FVB/NJ pups were injected twice-daily with morphine (10mg/kg, s.c.) or saline (0.9%, 20 ul/g, s.c.) from postnatal day(P) 1 to P14. This protocol induces reduced weight gain, hypothermia, thermal hyperalgesia, and increased USVs during spontaneous morphine withdrawal.

RESULTS

On P14, there were increased USV emissions and altered USV syllables during withdrawal, including an increase in Complex 3 syllables in FVB/NJ females (but not males). Brainstem bulk mRNA sequencing revealed an upregulation of the kappa opioid receptor (Oprk1), which contributes to withdrawal-induced dysphoria. The kappa opioid receptor (KOR) antagonist, nor-BNI (30 mg/kg, s.c.), significantly reduced USVs in FVB/NJ females, but not males during spontaneous morphine withdrawal. Furthermore, the KOR agonist, U50,488h (0.625 mg/kg, s.c.), was sufficient to increase USVs on P10 (both sexes) and P14 (females only) in FVB/NJ mice.

CONCLUSIONS

We identified an elevated USV syllable, Complex 3, and a female-specific recruitment of the dynorphin/KOR system in increased USVs associated with neonatal opioid withdrawal severity.

The ultrasonic vocalization (USV) syllable profile during neonatal opioid withdrawal and a kappa opioid receptor component to increased USV emissions in female mice

Rationale

Opioid use during pregnancy can lead to negative infant health outcomes, including neonatal opioid withdrawal syndrome (NOWS). NOWS comprises gastrointestinal, autonomic nervous system, and neurological dysfunction that manifest during spontaneous withdrawal. Variability in NOWS severity necessitates a more individualized treatment approach. Ultrasonic vocalizations (USVs) in neonatal mice are emitted in isolation as a stress response and are increased during opioid withdrawal, thus modeling a negative affective state that can be utilized to test new treatments.

Objectives

We sought to identify the behavioral and USV profile, brainstem transcriptomic adaptations, and role of kappa opioid receptors in USVs during neonatal opioid withdrawal.

Methods

We employed a third trimester-approximate opioid exposure model, where neonatal inbred FVB/NJ pups were injected twice-daily with morphine (10mg/kg, s.c.) or saline (0.9%, 20 ul/g, s.c.) from postnatal day(P) 1 to P14. This protocol induces reduced weight gain, hypothermia, thermal hyperalgesia, and increased USVs during spontaneous morphine withdrawal.

Results

On P14, there were increased USV emissions and altered USV syllables during withdrawal, including an increase in Complex 3 syllables in FVB/NJ females (but not males). Brainstem bulk mRNA sequencing revealed an upregulation of the kappa opioid receptor (Oprk1), which contributes to withdrawal-induced dysphoria. The kappa opioid receptor (KOR) antagonist, nor-BNI (30 mg/kg, s.c.), significantly reduced USVs in FVB/NJ females, but not males during spontaneous morphine withdrawal. Furthermore, the KOR agonist, U50,488h (0.625 mg/kg, s.c.), was sufficient to increase USVs on P10 (both sexes) and P14 (females only) in FVB/NJ mice.

Conclusions

We identified an elevated USV syllable, Complex 3, and a female-specific recruitment of the dynorphin/KOR system in increased USVs associated with neonatal opioid withdrawal severity.

Teneurin C-terminal associated peptide (TCAP)-1 attenuates the development and expression of naloxone-precipitated morphine withdrawal in male Swiss Webster mice

RATIONALE

Corticotropin-releasing factor (CRF), the apical stress-inducing hormone, exacerbates stress and addictive behaviors. TCAP-1 is a peptide that directly inhibits both CRF-mediated stress and addiction-related behaviors; however, the direct action of TCAP-1 on morphine withdrawal-associated behaviors has not previously been examined.

OBJECTIVE

To determine whether TCAP-1 administration attenuates behavioral and physiological consequences of morphine withdrawal in mice.

METHODS

Mice were administered via subcutaneous route TCAP-1 either before or after initial morphine exposure, after which jumping behavior was quantified to assess the effects of TCAP-1 on naloxone-precipitated morphine withdrawal. As a comparison, mice were treated with nonpeptide CRF1 receptor antagonist CP-154,526. In one experiment, plasma corticosterone (CORT) was also measured as a physiological stress indicator.

RESULTS

Pretreatment with TCAP-1 (10-250 nmol/kg) before morphine treatment significantly inhibited the development of naloxone-precipitated withdrawal. TCAP-1 (250-500 nmol/kg) treatment administered after morphine treatment attenuated the behavioral expression of naloxone-precipitated withdrawal. TCAP-1 (250 nmol/kg) treatment during morphine treatment was more effective than the optimal dosing of CP-154,526 (20 mg/kg) at suppressing the behavioral expression of naloxone-precipitated withdrawal, despite similar reduction of withdrawal-induced plasma CORT level increases.

CONCLUSIONS

These findings establish TCAP-1 as a potential therapeutic candidate for the prevention and treatment of morphine withdrawal.

Exploring gene-drug interactions for personalized treatment of post-traumatic stress disorder

Introduction

Post-Traumatic Stress Disorder (PTSD) is a mental disorder that can develop after experiencing traumatic events. The aim of this work is to explore the role of genes and genetic variations in the development and progression of PTSD.

Methods

Through three methodological approaches, 122 genes and 184 Single Nucleotide Polymorphisms (SNPs) associated with PTSD were compiled into a single gene repository for PTSD. Using PharmGKB and DrugTargetor, 323 drug candidates were identified to target these 122 genes. The top 17 drug candidates were selected based on the statistical significance of the genetic associations, and their promiscuity (number of associated genestargets) and were further assessed for their suitability in terms of bioavailability and drug-like characteristics. Through functional analysis, insights were gained into the biological processes, cellular components, and molecular functions involved in PTSD. This formed the foundation for the next aspect of this study which was to propose an efficient treatment for PTSD by exploring drug repurposing methods.

Results

The main aim was to identify the drugs with the most favorable profile that can be used as a pharmacological approach for PTSD treatment. More in particular, according to the genetic variations present in each individual, the relevant biological pathway can be identified, and the drug candidate proposed will specifically target said pathway, accounting for the personalized aspect of this work. The results showed that the drugs used as off-label treatment for PTSD have favorable pharmacokinetic profiles and the potential drug candidates that arose from DrugTargetor were not very promising. Clozapine showed a promising pharmacokinetic profile and has been linked with decreased psychiatric symptoms. Ambrucin also showed a promising pharmacokinetic profile but has been mostly linked with cancer treatment.

The acceptability and feasibility of a virtual mantram program for patients with posttraumatic stress disorder and substance use disorders: mixed method results

BACKGROUND

There is a need for expanded options for therapeutic interventions for patients with posttraumatic stress disorder (PTSD) and substance use disorder (SUD). The study aimed to examine evidence for the feasibility, safety, and acceptability of a virtual Mantram Repetition Program for adults with PTSD and SUD.

METHODS

This project utilized mixed-method design (explanatory sequential design) to collect quantitative and qualitative data to evaluate the program in terms of its feasibility and acceptability. The program took place over Webex, an encrypted virtual platform. The group ran over 8 weeks, was 90 min in length, and facilitated by two individuals per cohort. Each group had 4-5 participants given each group cycle. The study used the Mantram Repetition Program which is a brief mindfulness based non-tramua focused group intervention.

RESULTS

Out of 43 participants enrolled, 5 people (11.6%) did not commence the program and 8 (18.6%) participants dropped out after commencing the program, resulting in 35 completers (81.4% retention rate). Treatment completion and retention were above 70%. Qualitative data explained several aspects of the program's acceptability including delivery methods, informative material provided and gaining a practical mindful tool to manage symptoms.

CONCLUSIONS

This study showed quantitative and qualitative evidence of the Mantram Repetition Program's feasibility, acceptability and safety to be used with individuals with PTSD-SUD. Although further evaluation of virtual Mantram Program to control group in longitudinal trials is needed to identify how it compares with other interventions in the field.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05058963, (28/09/2021).

Regulation of Cortico-Thalamic JNK1/2 and ERK1/2 MAPKs and Apoptosis-Related Signaling Pathways in PDYN Gene-Deficient Mice Following Acute and Chronic Mild Stress

The crosstalk between the opioidergic system and mitogen-activated protein kinases (MAPKs) has a critical role in mediating stress-induced behaviors related to the pathophysiology of anxiety. The present study evaluated the basal status and stress-induced alterations of cortico-thalamic MAPKs and other cell fate-related signaling pathways potentially underlying the anxiogenic endophenotype of PDYN gene-deficient mice. Compared to littermates, PDYN knockout (KO) mice had lower cortical and or thalamic amounts of the phospho-activated MAPKs c-Jun N-terminal kinase (JNK1/2) and extracellular signal-regulated kinase (ERK1/2). Similarly, PDYN-KO animals displayed reduced cortico-thalamic densities of total and phosphorylated (at Ser191) species of the cell fate regulator Fas-associated protein with death domain (FADD) without alterations in the Fas receptor. Exposure to acute restraint and chronic mild stress stimuli induced the robust stimulation of JNK1/2 and ERK1/2 MAPKs, FADD, and Akt-mTOR pathways, without apparent increases in apoptotic rates. Interestingly, PDYN deficiency prevented stress-induced JNK1/2 and FADD but not ERK1/2 or Akt-mTOR hyperactivations. These findings suggest that cortico-thalamic MAPK- and FADD-dependent neuroplasticity might be altered in PDYN-KO mice. In addition, the results also indicate that the PDYN gene (and hence dynorphin release) may be required to stimulate JNK1/2 and FADD (but not ERK1/2 or Akt/mTOR) pathways under environmental stress conditions.

Posttraumatic Stress Disorder, Suicidal Behavior, Substance Use, and Sexual Victimization Among Adolescent Girls Aged 10-19 Years Living Under Ethnic-Based Civil War in Ethiopia

BACKGROUND

Posttraumatic stress disorder (PTSD) is a chronic, impairing mental disorder that develops after exposure to a traumatic event. Despite many factors putting adolescent girls at risk of PTSD, little is known about the prevalence and how adolescent girls cope with the PTSD burden. So, this study aimed to investigate the prevalence of PTSD and associated factors among adolescent girls in three selected towns in Southwest Ethiopia.

METHODS

A community-based cross-sectional study was conducted among 397 adolescent girls from May 27 to July 27, 2021. The participants were selected by a systematic random sampling method. PTSD and substance use disorder were assessed by DSM V criteria for mental disorders. The data was entered into Epi Data Manager Version 4.0.2 before being exported to SPSS Version 25 for analysis. A logistic regression model was used, and variables with a p-value less than 0.05 in the final fitting model were stated as independent predictors of PTSD.

RESULTS

The prevalence of PTSD among the adolescent girls was 22%, and about three in four (72.7%) of the adolescent girls developed PTSD after exposure to sexual violence. Furthermore, PTSD was associated with Khat use disorder (AOR, 95% CI: 2.79 (1.47-5.30), alcohol use disorder (AOR, 95% CI: 5.27 (2.21-12.60), and suicidal behavior (AOR, 95% CI: 2.12 (1.20-3.74)).

CONCLUSION

The prevalence of PTSD was high among adolescent girls, and suicidal ideation or attempt, khat use disorder, and alcohol use disorder were risk factors for PTSD. Therefore, early screening for PTSD and comorbid risk factors among this particular age group and managing accordingly is warranted.