Pharmacologic analysis of non-synonymous coding h5-HT2A SNPs reveals alterations in atypical antipsychotic and agonist efficacies

Abstract

The 5-HT 2A -serotonin receptor is a major molecular target for most atypical antipsychotic drugs as well as most hallucinogens, which can exacerbate psychotic symptoms. In this study, we examined whether random sequence variations in the gene (single nucleotide polymorphisms, SNPs) encoding the 5-HT 2A -serotonin receptor could explain inter-individual variability in atypical antipsychotic and agonist drug response. We examined the in vitro pharmacology of four non-synonymous SNPs, which give rise to T25N, I197V, A447V, and H452Y variant 5-HT 2A -serotonin receptors. Our data indicate that these non-synonymous SNPs exert statistically significant, although modest, effects on the affinity and functional effects of several currently approved atypical antipsychotics (aripiprazole, clozapine, olanzapine, quetiapine, risperidone, and ziprasidone). Also, the 5-HT 2A receptor SNPs slightly altered the potency and relative efficacy of a small number of selected agonists (2,5-dimethoxy-4-iodoamphetamine, tryptamine, 5-hydroxytryptamine, m-chlorophenylpiperazine, and 5-methoxy-N, N-dimethyltryptamine). In all, our results show that the in vitro pharmacological effects of the SNPs are drug specific.

Identifying Nonselective Hits from a Homogeneous Calcium Assay Screen

“…Culture media containing 10% fetal bovine serum (FBS) plus metabolic byproducts from cells grown overnight may well influence assay performance. Although advertised as a "no-wash" product, 6 cell washing 1,4,[7][8][9] or media aspiration 2,10 steps are often part of the manufacturer's suggested protocols. However, using homogeneous calcium dye assay kits with washing or aspiration steps decreases their value by (1) including potential cell perturbation-causing calcium mobilization artifacts through washing (a similar mechanism demonstrated using centrifugation and resuspension 11 ), (2) not increasing screening throughput due to plate washing or media aspiration time and labor, and (3) in some kits, adding a proprietary quencher, a potential assay variable.…”

“…The selected primary hits are subsequently rescreened against the parental cell line to identify and eliminate compounds having off-receptor, endogenous activity (nonselective hits). Although homogeneous calcium dye kits for high-throughput screening (HTS) historically work well for both agonists [1][2][3] and antagonists, 4 we observed a high false-positive rate in a modest agonist campaign (50,000 compounds). We rescreened hundreds of primary hits against the parental cell line (same homogeneous calcium dye kit) and confirmed only 1 selective active hit.…”

Mechanisms of development of antipsychotic-induced metabolic disorders: pharmacogenetic aspect

“…Исследование несинонемичных по-лиморфизмов T25N, l197V, A447V, H452Y гена HTR2A дало статистически значимое изменение аффиности рецептора с атипичными антипсихо-тиками по сравнению с диким типом. Двукрат-ное увеличение аффинности зарегистрировано у носителей варианта l197V при приеме арипипра-зола, десятикратное увеличение -при полимор-физме l197V на фоне приема клозапина, четырех-кратное увеличение -у носителей полиморфизма T25N при приеме кветиапина и трехкратное уве-личение -при полиморфизме H452Y у прини-мавших рисперидон; тридцатикратное снижение аффинности выявлено при приеме ариприпазола у носителей полиморфизма T25N [72].…”

“…Исследование несинонемичных по-лиморфизмов T25N, l197V, A447V, H452Y гена HTR2A дало статистически значимое изменение аффиности рецептора с атипичными антипсихо-тиками по сравнению с диким типом. Двукрат-ное увеличение аффинности зарегистрировано у носителей варианта l197V при приеме арипипра-зола, десятикратное увеличение -при полимор-физме l197V на фоне приема клозапина, четырех-кратное увеличение -у носителей полиморфизма T25N при приеме кветиапина и трехкратное уве-личение -при полиморфизме H452Y у прини-мавших рисперидон; тридцатикратное снижение аффинности выявлено при приеме ариприпазола у носителей полиморфизма T25N [72].Поскольку атипичные антипсихотики взаимо-действуют с адренорецепторами, ОНП послед-них также может играть важную роль в фар-макодинамике препарата. Однонуклеотидный полиморфизм 1291C/G гена ADRA2A с аллель-ным вариантом G/G ассоциирован с высоким риском развития антипсихотик-индуцированно-го набора веса [73].…”

High-Dose Olanzapine for Treatment-Resistant Schizophrenia

“…Indeed, we have demonstrated recently that some SNPs in the 5-HT 2A serotonin receptor-a major target for clozapine and olanzapine-modulate olanzapine's activity. 13 Further study will be required to fully explore this possibility.…”