Inflammatory Mediator Serotonin Receptor Gene (5-HTR3A) Expression Changes on Human Peripheral Blood Lymphocytes in Rheumatoid Arthritis

The 5-HT3 receptor is a pentameric ligand-gated cation channel located in the central and peripheral nervous system and on extraneuronal locations like lymphocytes, monocytes and fetal tissue. Serotonin receptor gene expressions and their alterations in RA diseases have not been reported. The aim of this study is to show whether the serotonin receptor gene expresses on peripheral blood lymphocytes and also to characterise the lymphocyte serotonin receptor expression profiles in patients suffering from rheumatoid arthritis (RA). In the present study, using RT-PCR technique, the research team investigated 5-HT3A receptor gene expression in peripheral blood lymphocyte cells (PBMC) of forty healthy individuals compared to forty RA patients. The PBMC was separated from whole blood by Ficoll-hypaque. Total cellular RNA was extracted and then cDNA was synthesized. The research team analyzed quantititavely gene expression profile by Real time-PCR using primer pairs specific for 5-HT3A receptor and for β-actin as internal control. Each PCR product of 5-HT3A receptor was confirmed by DNA sequencer ABI 3700 capillary system (Applied Biosystem, USA). The results showed that the 5-HT3A receptor gene is detected on the lymphocytes of both normal control and RA patients. There was a significant difference between 5-HT3A receptor expression profile in RA and that of healthy individuals. Moreover, no SNP-based change on sequenced fragments was observed. In conclusion, the present study indicated that not only human lymphocytes in normal individuals and patients express 5HT3A receptor, but the expression pattern of 5HT3A receptor gene is different between normal controls and RA patients. Moreover, after sequencing no changes in either controls or patients were observed. The above-mentioned changes can contribute to new information related to the pathogenesis of RA disease.