Peripheral Blood Mononuclear Cell Expression of Cation-Chloride Cotransporter (CCC) Genes in Premenstrual Dysphoric Disorder (PMDD) across the Menstrual Cycle-A Preliminary Study.

Premenstrual Dysphoric Disorder (PMDD) is a psychiatric condition characterized by debilitating affective symptomatology in the luteal phase of the menstrual cycle. Based on the previous reports that PMDD may be related to GABAergic cellular dysfunction(s), we assessed whether cation-chloride cotransporter (CCC) gene expression across the menstrual cycle is altered in PMDD. As there are limitations in accessing the human CNS to study CCC-encoding genes, we utilized peripheral blood mononuclear cells (PBMCs) as an alternative model. We first sought to replicate previous reports characterizing CCC gene expression patterns in PBMCs of reproductive age women. We subsequently investigated potential distinct CCC mRNA expression patterns in women with PMDD. We collected blood samples across 8 menstrual cycle visits for PBMC separation/RNA extraction to study mRNA expression of four KCCs (KCC1, KCC2, KCC3, KCC4) and two NKCCs (NKCC1, NKCC2) cotransporters. We mostly replicated the earlier gene expression pattern findings, and found that the expression levels of KCC1 were significantly downregulated during the mid-follicular and periovulatory subphases of the menstrual cycle in women with PMDD. The present study shows that PBMCs is a valid model for studying GABAergic mechanisms underlying PMDD.