Anorexia nervosa (AN) is associated with low bone density in adolescents and adults. Hypercortisolemia has been reported in adults with this disorder and has been hypothesized to be a factor in bone loss. However, the secretory dynamics of cortisol in adolescents with AN and the contribution of alterations in cortisol secretion to bone metabolism in AN have not been examined. We examined the dynamics of cortisol secretion by Cluster and deconvolutional analysis in 23 girls with AN and 21 healthy adolescents of comparable age and maturity. Cortisol sampling was performed every 30 min for 12 h overnight. Twenty-four-hour urinary free cortisol (UFC) and creatinine (cr) were obtained for all subjects. The surface area (SA) of the subjects was calculated. Markers of bone turnover (type 1 procollagen, osteocalcin, and N-telopeptide) were examined. Subjects with AN were prospectively followed over 1 yr, and those who recovered weight (defined as a 10% increase in body mass index) were again studied. On Cluster analysis, girls with AN had significantly higher mean cortisol (8.6 +/- 2.0 vs. 5.9 +/- 1.1 microg/dl; P < 0.0001), nadir cortisol (5.5 +/- 2.3 vs. 3.4 +/- 1.2 microg/dl; P = 0.0008), valley mean cortisol (7.0 +/- 2.7 vs. 4.7 +/- 1.5 microg/dl; P = 0.001), peak amplitude (12.6 +/- 4.4 vs. 7.8 +/- 3.0 microg/dl; P = 0.0004), peak area (652 +/- 501 vs. 340 +/- 238 microg/dl; P = 0.02), and total area under the curve (6112 +/- 1467 vs. 4117 +/- 802 microg/dl; P < 0.0001) than healthy adolescents. On deconvolutional analysis, the frequency of nocturnal secretory bursts (7.0 +/- 1.2 vs. 5.8 +/- 1.3 /12 h; P = 0.001), total nocturnal pulsatile cortisol secretion (69.3 +/- 14.7 vs. 53.9 +/- 11.1 microg/dl; P = 0.0003), and total cortisol secretion (89.6 +/- 18.8 vs. 71.2 +/- 17.6 microg/dl; P = 0.002) were significantly higher in girls with AN than in healthy controls. Cortisol half-life trended higher in girls with AN. However, basal cortisol secretion and approximate entropy did not differ between the groups. UFC/cr and UFC/cr.SA were significantly higher in girls with AN than in controls [0.050 +/- 0.028 vs. 0.036 +/- 0.017 (P = 0.04) and 0.035 +/- 0.020 vs. 0.023 +/- 0.012 (P = 0.03)]. Six of 23 girls with AN had UFC/cr.SA values that were more than 2 sd above those in healthy controls. An inverse correlation was noted between measures of cortisol concentration as well as pulsatile secretion and measures of nutritional status (body mass index, fat mass, leptin, insulin, and IGF-I). An oral glucose load suppressed cortisol levels in healthy adolescents, but not in AN patients. Weight recovery was associated with a significant decrease in the number of secretory bursts. In girls with AN, strong inverse correlations were noted between levels of cortisol (mean, nadir, and total area under the curve) and levels of markers of bone formation (C-terminal propeptide of type 1 procollagen and osteocalcin). Conversely, in healthy controls, cortisol values did not predict levels of markers of bone turnover. Adolescent girls with...

SUMMARY Iron regulatory proteins 1 and 2 (Irps) post-transcriptionally control the expression of transcripts that contain iron responsive element (IRE) sequences, including ferritin, ferroportin, transferrin receptor and hypoxia inducible factor 2α (HIF2α). We report here that mice with targeted deletion of Irp1 developed pulmonary hypertension and polycythemia that was exacerbated by a low iron diet. Hematocrits increased to 65% in iron-starved mice, and many polycythemic mice died of abdominal hemorrhages. Irp1 deletion enhanced HIF2α protein expression in kidneys of Irp1−/− mice, which led to increased erythropoietin (EPO) expression, polycythemia and concomitant tissue iron deficiency. Increased HIF2α expression in pulmonary endothelial cells induced high expression of endothelin-1, likely contributing to the pulmonary hypertension of Irp1−/− mice. Our results reveal why anemia is an early physiological consequence of iron deficiency, highlight the physiological significance of Irp1 in regulating erythropoiesis and iron distribution, and provide important insights into the molecular pathogenesis of pulmonary hypertension.

Aberrant gene expression is a hallmark of acute leukemias. MYB-driven transcriptional coactivation with CREB-binding protein (CBP)/P300 is required for acute lymphoblastic and myeloid leukemias, including refractory MLL-rearranged leukemias. Using structure-guided molecular design, we developed a peptidomimetic inhibitor MYBMIM that interferes with the assembly of the molecular MYB:CBP/P300 complex and rapidly accumulates in the nuclei of AML cells. Treatment of AML cells with MYBMIM led to the dissociation of the MYB:CBP/P300 complex in cells, its displacement from oncogenic enhancers enriched for MYB binding sites, and downregulation of MYB-dependent gene expression, including of MYC and BCL2 oncogenes. AML cells underwent mitochondrial apoptosis in response to MYBMIM, which was partially rescued by ectopic expression of BCL2. MYBMIM impeded leukemia growth and extended survival of immunodeficient mice engrafted with primary patient-derived MLL-rearranged leukemia cells. These findings elucidate the dependence of human AML on aberrant transcriptional coactivation, and establish a pharmacologic approach for its therapeutic blockade.