Endocrine Abstracts

Introduction: CLOCK system is a highly conserved, ubiquitous molecular ‘clock’ which creates internal circadian rhythmicity under the influence of light/dark information. CLOCK system is regulated by the coordinated activation/inactivation of several transcription factors, including the CLOCK, the BMAL1 and other essential regulators, such as the Pers, Crys and RORs. The present study aimed to evaluate the circadian rhythm of clock-related genes expressed in patients with polyglandular autoimmune syndrome type III (PASIII). Methods Sixteen patients diagnosed with PASIII and nine healthy controls were enrolled. Patients and controls were age and gender-matched. All patients had normal adrenal function. We analysed mRNA and protein expression by real-time PCR and western blot analysis of CLOCK-related and glucocorticoid receptor (GR) genes isolated from the peripheral blood mononuclear cells (PBMCs) from blood samples drawn at 0800 and 2000 h. At the same time, plasma cortisol and ACTH were also measured by chemiluminescence. Statistical analysis were performed with spss,vs 20.

Results: Our data showed a significant increase in the evening to morning CLOCK, GR, BMAL1, ROR and PER3 mRNA expression ratio (R_pm/am) in patients compared to controls (P=0.006, P=0.04, P=0.004, P=0.02 and P=0.004 respectively). In patients the amplitude of cortisol circadian variation (ΔF_{0800–2000 h}) demonstrated a significant positive correlation with the R_pm/am of CLOCK, BMAL1 and Per 3 expression (P=0.033, P=0.02 and P=0.03 respectively) whereas in controls ΔF_{800–2000 h} presented a significant negative correlation with the R_pm/am of CLOCK and BMAL1 (P=0.07 and P=0.007). No significant correlation was found between ΔF_{800–2000 h} and GR or ROR expression, neither in patients nor in controls.

Conclusions: These findings suggest that there is an abberant expression of clock-related genes in patients with PASIII compared to healthy controls. Daily pattern expression of five circadian clock genes was disrupted in patients with PAS III indicating a possible association with the pathogenesis of the disease.