INVESTIGATING THE ROLE OF DYNAMIC SIGNALING OF NRG3-ERBB4 IN THE PREFRONTAL CORTEX IN MEDIATING NICOTINE WITHDRAWAL PHENOTYPES

Author

Emily Prantzalos, University of KentuckyFollow

Author ORCID Identifier

https://orcid.org/0000-0001-8098-5601

Date Available

10-22-2025

Year of Publication

2025

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy (PhD)

College

Pharmacy

Department/School/Program

Pharmaceutical Sciences

Faculty

Jill Turner

Abstract

While several pharmacotherapies are currently available for nicotine use disorder (NUD), smoking cessation success rates remain below 10% each year. The molecular mechanisms underlying failed quit attempts continue to represent a critical gap in our knowledge. However, recent advances in understanding the genetic contributions to nicotine dependence offer a promising avenue for developing more effective cessation therapies. Prior research has identified genetic variation in Neuregulin 3 (Nrg3) and its cognate receptor ErbB4 as potential contributors to affective nicotine withdrawal (WD) phenotypes and cessation outcomes. Therefore, this dissertation aims to systematically investigate the region-specific, functional role of the Neuregulin Signaling Pathway (NSP) during nicotine exposure and WD.

The prefrontal cortex (PFC), a critical brain region for emotional regulation, cognitive function, and decision-making, is particularly vulnerable to the effects of nicotine exposure and WD. Given its relevance to NUD and comorbid psychiatric conditions such as schizophrenia, this work focuses on PFC-specific ErbB4 function. Additional exploratory studies evaluated the potential of repurposing aripiprazole, an atypical antipsychotic shown to modulate the NSP and reduce smoking in patients with schizophrenia, as a candidate treatment for WD symptoms. Experiments in Chapters 2 and 3 assess the effects of NSP manipulation by using an ErbB4-flox mouse model or aripiprazole administration in mice exposed to chronic nicotine followed by 24-hour spontaneous WD. Behavioral assays for anxiety-like phenotypes were paired with transcriptomic analyses of medial PFC (mPFC) and orbitofrontal cortex (OFC) tissue, using RT-qPCR, RNAscope, and bulk RNA sequencing to characterize the expression of NSP components and related synaptic signaling pathways.

Chapter 2 demonstrates that mPFC-specific knockdown (KD) of ErbB4 alters nicotine WD-related behaviors in a sex-specific manner. In the acoustic startle response (ASR) task, ErbB4 KD resulted in a prominent reduction of startle response in WD males, while in the open field (OF) test, only females showed reduced thigmotaxis during WD. OF fecal output mirrored ASR patterns, suggesting distinct effects of ErbB4 on emotional reactivity and anxiety-like behavior across sexes. Molecular analyses revealed that ErbB4 KD attenuated WD-induced Nrg3 upregulation. This finding is complemented by reductions in glutamatergic N-methyl-D-aspartate receptor (NMDAR) subunits 2A and 2B, as well as reciprocal subregion-specific transcriptional changes. Chapter 3 explores aripiprazole as a potential WD therapeutic, as administration reduces anxiety-like behaviors during WD, with corresponding sex-, subregion- and treatment-specific changes in prefrontal expression of genes related to the NSP, glutamatergic signaling, and serotonin receptors.

In summary, chronic nicotine exposure dysregulates region-specific NSP and glutamatergic gene expression in the PFC, exacerbating anxiety-like symptoms during WD. ErbB4 signaling in the mPFC is necessary for the presentation of these behavioral deficits. Aripiprazole alleviates WD-related anxiety-like behavior in mice through sex-dependent transcriptional modulation of neuroplasticity-related pathways. Overall, these findings employ a multidisciplinary approach to highlight the role of Nrg3-ErbB4 signaling in the molecular and behavioral effects of nicotine WD and provide a mechanistic framework for developing personalized treatments that target affective disruption to improve smoking cessation outcomes.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2025.465

Funding Information

This study was supported by the National Institute of Health National Institute on Drug Abuse [Grants R01-DA-044311 (2020-2025) and F31-DA-057812 (2023-2025)]. It was also supported by an American Foundation for Pharmaceutical Education (AFPE) regional award (2023-2024), as well as by pilot funds from the University of Kentucky’s Substance Use Priority Research Area (SUPRA) (2023-2024), supported by the Vice President for Research.

Recommended Citation

Prantzalos, Emily, "INVESTIGATING THE ROLE OF DYNAMIC SIGNALING OF NRG3-ERBB4 IN THE PREFRONTAL CORTEX IN MEDIATING NICOTINE WITHDRAWAL PHENOTYPES" (2025). Theses and Dissertations--Pharmacy. 172.
https://uknowledge.uky.edu/pharmacy_etds/172