Research PaperA peptide disrupting the D2R-DAT interaction protects against dopamine neurotoxicity

- DAT-S1 peptide inhibits dopamine-induced cell death.
- DAT-S1 peptide disrupts the D2R-DAT interaction during dopamine treatment.
- DAT-S1 peptide decreases DAT expression on cell surface membrane during dopamine treatments.
- DAT-S1 peptide inhibits caspase-3 and PARP-1 cleavage.

Dopamine reuptake from extracellular space to cytosol leads to accumulation of dopamine, which triggers neurotoxicity in dopaminergic neurons. Previous studies have shown that both dopamine D2 receptor (D2R) and dopamine transporter (DAT) are involved in dopamine neurotoxicity. However, blockade of either D2R or DAT causes side effects due to antagonism of other physiological functions of these two proteins. We previously found that DAT can form a protein complex with D2R and its cell surface expression is facilitated via D2R-DAT interaction, which regulates dopamine reuptake and intracellular dopamine levels. Here we found that an interfering peptide (DAT-S1) disrupting the D2R-DAT interaction protects neurons against dopamine neurotoxicity, and this effect is mediated by inhibiting DAT cell surface expression and inhibiting both caspase-3 and PARP-1 cleavage. This study demonstrates the role of the D2R-DAT complex in dopamine neurotoxicity and investigated the potential mechanisms, which might help better understand the mechanisms of dopamine neurotoxicity. The peptide may provide some insights to improve treatments for dopamine neurotoxicity and related diseases, such as Parkinson's disease, as well as methamphetamine- and 3,4-methsylenedioxy methamphetamine-induced neurotoxicity.

DAT-S1 peptide protects against dopamine neurotoxicity by disrupting the interaction between dopamine D2 receptor and dopamine transporter, reducing dopamine transporter expression on cell surface membrane, and inhibiting the cleavage of caspase-3 and Poly [ADP-ribose] polymerase 1, indicating that the peptide may be helpful to improve treatments of dopamine neurotoxicity and related diseases.105