# Establishing the Molecular Mechanisms of Reduced Ethanol Drinking in Calcineurin-Mediated Immunosuppression Treated Rodents

> **NIH VA I01** · VA EASTERN COLORADO HEALTH CARE SYSTEM · 2022 · —

## Abstract

Veteran populations present alcoholism rates that are far higher than general population frequencies.
Despite this, the treatment options for alcoholism are very few and much in need of new approaches for
medical interventions. This project grows from the observation that alcoholic persons receiving liver transplant
evidence very high rates of sustained abstinence after the liver grafting procedure that we could not explain by
psychosocial or selection factors. We asked whether this might be due to a common factor shared by all of
these patients: immunosuppressant medicines given for very long periods after transplant to keep the grafted
organ in a state of health. In two separate rodent experiments we found that 1) cyclosporine (CSA) had an
antidipsic effect in an open choice model of ethanol (alternatively alcohol, or ethyl alcohol) drinking, and 2) that
CSA and tacrolimus (TRL, alternately FK506) had similar effects in a drinking-in-the-dark (DID) ethanol
drinking model while sirolimus (SRL, alternately rapamycin) had no effect but had lower concentrations in the
brain. These findings implicate the immunosuppressants blocking brain calcineurin (CLN) activity that may
enhance the rodent's choice against drinking ethanol through 1) direct CLN modulation in the brain or 2)
through the systemic immunosuppressive and neuroimmune pathways. This study asks whether further
evidence supports one or the other of these possible mechanisms of action.
 Following the overall goal of this project--to elucidate the mechanism(s) of reduction of alcohol
preference by CLN directly or by CLN-mediated immunosuppression, the study's primary hypothesis asserts
that inhibition limiting CLN activity in the brain itself will decrease rodent ethanol choice. An alternative
hypothesis states that the peripheral effects of CLN inhibition in the immune system will result in a decrease in
ethanol preference. The overall aim of the project is therefore to establish which of these two possible
mechanisms mediates the effect of immunosuppressant agents on rodent's choice not to drink ethanol.
 Our experimental approaches address the primary hypothesis using a genetic knockout approach. In
Specific Aim 1, we will compare immunosuppressants in brain-specific CLN knock-out mice that include a)
pan-brain knockout (CamKIIα Cre x floxed CLN) rodents, b) CRF neuron specific calcineurin knockout
(CRHCrex floxed CLN), and c) focal CLN knockouts in extended reward regions (VTA, NAc, CeA) utilizing
AAV-Cre microinjections in floxed CLN mice. In Specific Aim 2, we will characterize the possible mechanisms
of central effects of CLN inhibition on alcohol consumption by assessing 1) the brain's metabolic protection by
CLN inhibitors, and 2) addiction related downstream signal molecules in extended brain reward networks. In
Specific Aim 3, we test whether drinking causes neuroinflammation that drives subsequent drinking. We will
use a combination of approaches (flow cytometry, immunohistochemi...

## Key facts

- **NIH application ID:** 10477241
- **Project number:** 5I01BX004712-04
- **Recipient organization:** VA EASTERN COLORADO HEALTH CARE SYSTEM
- **Principal Investigator:** THOMAS P BERESFORD
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2022
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2019-07-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10477241

## Citation

> US National Institutes of Health, RePORTER application 10477241, Establishing the Molecular Mechanisms of Reduced Ethanol Drinking in Calcineurin-Mediated Immunosuppression Treated Rodents (5I01BX004712-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10477241. Licensed CC0.

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