SUPPRESSION OF TENEURIN-4 IN THE NUCLEUS ACCUMBENS ALLEVIATES METHAMPHETAMINE-INDUCED DOPAMINE RELEASE AND BEHAVIORAL ALTERATIONS IN MICE
Authors: Wenbing *Chen , Takashi Asano , Notaka Izuo , Shin-Ichi Muramatsu , Atsumi Nitta 
Published: February 2025

Abstract

Background
According to the World Drug Report 2022 from United Nations, amphetamine-type stimulants take third place in worldwide drug addiction, primary methamphetamine (METH) [1]. And over 30,0000 people died from drug overdoses induced by stimulants combined with other drugs [2]. METH is recognized as a widely distributed psychostimulant with a strong addictive potential that impacts the central nervous system and body health [3]. METH predominantly exerts its influence on the limbic system through the stimulation of the release of various neurotransmitters, including dopamine, within the nucleus accumbens (NAc), a critical element of the brain's reward circuitry. Both short-term and prolonged METH use can result in lasting physical and mental health complications, some of which may endure indefinitely. Over the last decades, significant social problems associated with METH have gotten worse over the past few decades, especially after COVID-19 [1, 2].

Aim & Objectives
Our previous data revealed several genes associated with METH, including Odz4 gene. The Odz4 gene encodes teneurin-4 (TENM4) protein which belongs to one subtype of type II transmembrane teneurin proteins (TENM1-4) [4]. Genetic studies have indicated a correlation between teneurin proteins and developmental issues, neurological disorders, and drug residence [5]. Recently, some clinical research found that the Odz4 gene has an abnormal mutant in the brain of patients with bipolar disorder or schizophrenia [6, 7]. Based on the aforementioned research, it is suggested that TENM4 might play a role in the progress of drug addiction. Here we investigated the performance of TENM4 knockdown in METH-induced dopamine release of NAc shell and behavior alterations in mice.

Method
We administered METH or saline subcutaneously to mice for six consecutive days. Two hours after the final injection of METH, we sacrificed all mice and preserved them under 80°. Then we investigated the changes in Odz4 mRNA and protein levels using RT-qPCR and WB, respectively. Subsequently, we injected AAV-carrying Odz4-targeting gRNA involved CRISPR-Cas system into the NAc After four weeks of the injection, we assessed the time response of dopamine in NAc by in vivo microdialysis and alteration of conditioned place preference induced by METH.

Results
We found a significant increase in Odz4 mRNA and TENM4 protein levels in the NAc region after continued METH administration. We confirmed the knockdown effect by AAV injection of the NAc of mice. The TENM4 knockdown exhibited an attenuated response of dopamine and place preference induced by METH.

Discussion and Conclusion
These results indicate the association between TENM4 and the pharmacological effects of METH in NAc region of mice. However, addiction behaviors affected by the knockdown of TENM4 and its specific mechanisms underlying this relationship remain unclear and require further investigation.

References
1.United Nations Office on Drugs and Crime. (2022). World Drug Report 2022. Vienna. UNODC. Available from: World Drug Report 2022 (unodc.org) (Accessed: 12 October 2023)
2.National Institute on Drug Abuse 2022, 'Overdose Death Rates', [Online] Available from: Drug Overdose Death Rates | National Institute on Drug Abuse (NIDA) (nih.gov) (Accessed: 11 October 2023).
3.Cruickshank, C. C., &Dyer, K. R. (2009). A review of the clinical pharmacology of methamphetamine. Addiction, 104(7), 1085-1099. doi: 10.1111/j.1360-0443.2009.02564.x
4.Wang, L., Rotzinger, S., Al Chawaf, A., Elias, C. F., Barsyte-Lovejoy, D., Qian, X.,... &Lovejoy, D. A. (2005). Teneurin proteins possess a carboxy terminal sequence with neuromodulatory activity. Molecular brain research, 133(2), 253-265. doi: 10.1016/j.molbrainres.2004.10.019
5.Ziegler, A., Corvalan, A., Roa, I., Branes, J. A., &Wollscheid, B. (2012). Teneurin protein family: an emerging role in human tumorigenesis and drug resistance. Cancer letters, 326(1), 1-7. doi: 10.1016/j.canlet.2012.07.021
6.Sklar, P., Ripke, S., Scott, L.J. et al. (2011) Large-scale genome-wide association analysis of bipolar disorder identifies a new susceptibility locus near ODZ4. Nature Genetics, 43(10), 977-983. doi: 10.1038/ng.943
7.Yi, X., Li, M., He, G., Du, H., Li, X., Cao, D.,... &Zhou, D. (2021). Genetic and functional analysis reveals TENM4 contributes to schizophrenia. Iscience, 24(9). doi: 10.1016/j.isci.2021.103063