Expression of mRNA for multiple serotonin (5-HT) receptor types/subtypes by the peripheral blood mononuclear cells of rhesus macaques

Abstract 

To find out whether rhesus macaque peripheral blood mononuclear cells (PBMCs) express mRNA for 5-HT receptors, blood samples from normal healthy rhesus monkeys were used to isolate PBMCs by Ficoll-paque density gradient centrifugation. Total RNA was extracted from MT-2 cells, Hut-78 cells, naive or phytohemagglutinin (PHA) stimulated human and monkey PBMCs. One tube RT-PCR was performed using primers specific for human 5-HT1_A, 5-HT1_B, 5-HT1_E, 5-HT2_A, 5-HT2_B, 5-HT2_C, 5-HT3, 5-HT4, 5-HT6, and 5-HT7 receptors. Amplicons of expected sizes were obtained from human cell lines as well as both human and monkey PBMCs. Both PHA stimulated human and monkey PBMCs express mRNAs for 5-HT1_A, 5-HT1_B, 5-HT1_E, 5-HT2_A, 5-HT3, 5-HT4, 5-HT6 receptor types/subtypes. However, mRNAs for 5-HT1_B, 5-HT1_E and 5-HT2_A cannot be confidently detected in some of the PBMC samples without PHA stimulation. 5-HT2_B and 5-HT7 receptor mRNA was not detected in most of the samples and 5-HT2_C receptor mNRA was not detected at all. FACS analysis revealed that CD3+ lymphocyte increased more than 20% among lymphocytes in the PHA stimulated PBMCs. These data indicate that similar to human PBMC, rhesus macaque PBMC may express multiple types of 5-HT receptors and the expression profile could change after PHA stimulation due to either the changes in cell composition or changes in gene transcription level. This provided a basis for further studies on the neuroimmunomodulatory interactions of 5-HT in rhesus macaques.

Keywords: Serotonin, 5-HT receptors, One-step RT-PCR, PBMCs, Macaca mulatta