The screening model for dopamine receptor agonists by a dopamine sensor / 药学学报

ABSTRACT

Parkinson's disease (PD) is a degenerative disease of the central nervous system due to the loss or death of dopaminergic neurons in the substantia nigra. Clinically, levodopa is the most effective and commonly used drug for PD treatment. However, long-term levodopa therapy is prone to motor complications and other side effects caused by excessive peripheral dopamine production, which has become an urgent problem to be solved in PD treatment. Dopamine receptor (DR) agonists are similar to dopamine. They can directly stimulate postsynaptic dopamine receptors, produce the same effect as dopamine, delay the application of levodopa as much as possible, and reduce complications caused by long-term use of levodopa. Therefore, screening effective dopamine receptor agonists has become a key issue in the study and treatment of PD. In order to establish a rapid, stable and reliable method for dopamine receptor agonist screening, this study used the human dopamine receptor 2 (DRD2) gene fused with a circular permuted EGFP (cpEGFP) to construct a recombinant gene, packaged with lentiviral vector, and the vector replaced the parted inner transmembrane domain of the third intracellular loop (ICL3) of genetically-encoded GPCR-activation based (GRAB) sensors. The fluorescence of GPCR-fused cpEGFP is regulated by conformational changes mediated by the interaction of dopamine receptor agonists with GPCRs without altering GPCR activity. The HEK293T cells were infected with viral vector, screened by puromycin to select highly expressed cells. Dopamine receptor agonists (including dopamine, bromocriptine mesylate, cabergoline, pramipexole) were used as positive drugs to explore the best screening and detection conditions, establishing a stable model to evaluate the dopamine receptor agonist. The results showed that the optimal filter for the dopamine receptor agonist in this study was the cell seeding count of 7×104, and the effective concentration of the positive drug was 1-100 µmol·L-1. In addition, pretreated with 10 µmol·L-1 dopamine receptor antagonists (including chlorprothixol hydrochloride, domperidone, and sulpiride), the positive fluorescence signal of overexpressed DRD2-cpEGFP HEK293T cells could not be detected when exposed to 10 µmol·L-1 dopamine receptor agonists, which proved that dopamine receptor antagonists could block the activity of dopamine receptor agonists, so they cannot activate dopamine receptor allosteric, indicating that the model has good specificity and can also be used for the screening and detection of new dopamine receptor antagonists. In summary, the study constructs a stable dopamine sensor detection system, which can effectively screen potential dopamine receptor agonists. The operation procedures are simple and rapid. And it can be used for a large-scale screening providing a fundamental methodology for drug development and PD treatment targeted on DRD2.