miR-324-5p and miR-30c-2-3p Alter Renal Mineralocorticoid Receptor Signaling under Hypertonicity.

The Mineralocorticoid Receptor (MR) mediates the sodium-retaining action of aldosterone in the distal nephron, but mechanisms regulating MR expression are still poorly understood. We previously showed that RNA Binding Proteins (RBPs) regulate MR expression at the post-transcriptional level in response to variations of extracellular tonicity. Herein, we highlight a novel regulatory mechanism involving the recruitment of microRNAs (miRNAs) under hypertonicity. RT-qPCR validated miRNAs candidates identified by high throughput screening approaches and transfection of a luciferase reporter construct together with miRNAs Mimics or Inhibitors demonstrated their functional interaction with target transcripts. Overexpression strategies using Mimics or lentivirus revealed the impact on MR expression and signaling in renal KC3AC1 cells. miR-324-5p and miR-30c-2-3p expression are increased under hypertonicity in KC3AC1 cells. These miRNAs directly affect Nr3c2 (MR) transcript stability, act with Tis11b to destabilize MR transcript but also repress Elavl1 (HuR) transcript, which enhances MR expression and signaling. Overexpression of miR-324-5p and miR-30c-2-3p alter MR expression and signaling in KC3AC1 cells with blunted responses in terms of aldosterone-regulated genes expression. We also confirm that their expression is increased by hypertonicity in vivo in the kidneys of mice treated with furosemide. These findings may have major implications for the pathogenesis of renal dysfunctions, sodium retention, and mineralocorticoid resistance.

Factors Affecting Loss to Follow-Up in Children and Adolescents with Chronic Endocrine Conditions.

OBJECTIVE: Most children with endocrine diseases require long-term continuity of care. We investigated the prevalence of loss to follow-up (LTFU) in pediatric patients with chronic endocrine diseases and the risk factors associated with LTFU. METHODS: This observational cohort study included all children with chronic endocrine diseases included in the database of a single academic pediatric care center over a period of 8 years. LTFU was defined as a lack of attendance at clinical visits for over 2 years, for unknown reasons. RESULTS: LTFU was recorded for 154 of the 1,067 patients included (14%). Median age at diagnosis was 5.8 (0.3-11.8) vs. 1.2 (0.0-6.9) years, and age at last visit was 14.1 (9.7-16.1) vs. 11.7 (6.1-15.8) years, for the LTFU and no-LTFU groups, respectively. In multivariate analysis, the risk of LTFU increased with age at diagnosis (OR 1.18; 95% CI 1.12-1.24) and was higher for patients diagnosed before 2006 (vs. after 2006; OR 4.80; 95% CI 3.00-7.66), with fewer visits in the last 3 years (OR 0.72; 95% CI 0.65-0.80; p < 0.0001) and a lower health insurance classification (OR 1.79; 95% CI 1.10-2.89; p = 0.02). The risk of LTFU was higher for patients with isolated growth hormone deficiency than for those with other endocrine conditions, such as multiple pituitary deficiencies, hypogonadotropic hypogonadism, Turner syndrome, or thyroid, adrenal, or gonadal disorders (OR 5.24; 95% CI 1.13-24.37; p = 0.03). CONCLUSION: This study provides the first epidemiological data for LTFU in children and adolescents with chronic endocrine diseases. It should facilitate the targeting of interventions to improve adherence to medical care and healthcare organization during the pediatric period.