PRL-R ISOFORMS LONG / SHORT RATIO IS INCREASED IN SYSTEMIC LUPUS ERYTHEMATOSUS BLOOD MONONUCLEAR CELLS

Prolactin (PRL) displays several functions in the whole body by binding its receptor (PRL-R). Two main PRL-R isoforms are reported that differ in their capacity to trigger signaling pathways, PRL-R long isoform is the activation receptor, and the short isoform is the inhibitory oner. Although many autoimmune diseases display hyperprolactinemia, the role of each PRL-R isoform expression in autoimmunity remains unknown. This work aimed to correlate PRL-R isoforms expression in human peripheral blood mononuclear cells (PBMCs) of female Systemic Lupus Erythematosus patients and healthy controls. To this end, PBMCs from lupus patients (n=9) and healthy controls (n=5) were enriched by the ficoll-hypaque method. Then, RNA extraction, cDNA synthesis, and real-time PCR were performed to determine mRNA expression. We found that PRL-R long and short isoforms expression from lupus patients display similar expression to healthy controls. However, the PRL-RL/PRL-RS ratio is higher than healthy controls (P-value two-tailed <0,05). Additionally, PRL-RL isoform expression correlates with the short isoform in lupus patients (Spearman r 0,8945; 95% confidence interval 0,6834 to 0,9676; P-value two-tailed <0,0001). However, the expression of neither long and short isoforms correlates with active disease nor disease duration. Similarly, lupus patients display similar PRL-R isoforms expression than healthy controls. Although much work must be done, our data indicate that similar mechanisms may regulate the expression of both PRL-R isoforms in immune cells, and “their expression goes hand by hand”. , ,