NEAT1_2 and DAZAP1, Paraspeckle Components, Interact with PXR to Negatively Regulate CYP3A4 Induction

Human pregnane X receptor (PXR) is a major nuclear receptor that upregulates the expression of drug-metabolizing enzymes such as CYP3A4. In our recent study, it was revealed that PXR interacts with DAZ-associated protein 1 (DAZAP1), which is an essential component of the paraspeckle, a membraneless nuclear body, and the interaction was disassociated by rifampicin, a ligand of PXR. The purpose of this study was to clarify the roles of paraspeckles in PXR-mediated transcriptional regulation. Immunoprecipitation assays using PXR-overexpressing HepG2 (ShP51) cells revealed that PXR interacts with not only DAZAP1 but also NEAT1_2, a long noncoding RNA included in the paraspeckle, and that the interaction between PXR and NEAT1_2 was disassociated by rifampicin. These results suggest that PXR is trapped in paraspeckles and that the activation of PXR by its ligands facilitates its disassociation from paraspeckles. Induction of CYP3A4 by rifampicin was significantly enhanced by the knockdown of NEAT1_2 or DAZAP1 in ShP51 cells and their parental HepG2 cells. A luciferase assay using a plasmid containing the PXR response elements of CYP3A4 revealed that the increased CYP3A4 induction by siNEAT1_2 or siDAZAP1 was due to the increased transactivation by PXR. These results suggest that paraspeckles play a role in trapping nuclear PXR in the absence of the ligand to negatively regulate transactivation of its downstream gene. Collectively, this is the first study to demonstrate that the paraspeckle components NEAT1_2 and DAZAP1 negatively regulate CYP3A4 induction by PXR. SIGNIFICANCE STATEMENT: This study revealed that PXR interacts with paraspeckle components NEAT1_2 and DAZAP1 to suppress CYP3A4 induction by PXR, and the interaction is dissociated by PXR ligands. This finding provides a novel concept that paraspeckles formed by liquid-liquid phase separation potentially affect drug metabolism via negative regulation of PXR function.

Developmentally delimited emergence of more orderly luteinizing hormone and testosterone secretion during late prepuberty in boys

To quantitate changing feedback control in the GnRH-LH/FSH-testosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early prepuberty (genital stage I-A: mean bone age, 4.6 +/- 1.6 yr; testis volume, <3 mL for at least 3 succeeding yr) and late prepuberty (genital stage I-C: bone age, 8.7 +/- 1.8 yr; testis volume, <3 mL for up to 1 yr thereafter; P: = 0.00019), which indicates the acquisition of more regular LH release patterns in late prepuberty. Maximal LH orderliness occurred in puberty stage II (bone age, 10.7 +/- 1.0 yr; testis volume, 2.8 +/- 0.4 mL). The LH secretory process was more disorderly in mid- and later puberty (Tanner stages III and IV). Transpubertal variations in testosterone ApEn manifested a similar tempo, i.e. the greatest regularity of testosterone secretion (lowest ApEn) emerged in Tanner genital stage II (P: < 10(-)(7)), with less orderly patterns evident both earlier and later in sexual development. In contrast, FSH ApEn values remained invariant of pubertal status. Analysis of bihormonal coupling using the theoretically related bivariate cross-ApEn statistic disclosed maximal 2-hormone synchrony for LH and testosterone secretion in genital stage II (P: = 0.031), with relative deterioration of coordinate LH and testosterone release patterns both before and after. LH and FSH release became maximally synchronous at the end of prepuberty (genital stage I-C; P: = 0.029), and FSH and testosterone synchrony peaked in pubertal stage III (P: = 0.037). As mean 24-h serum concentrations of LH, FSH, and testosterone rose transpubertally by 35-fold (LH), 68-fold (FSH), and 70-fold (testosterone), respectively, we infer that pubertal developmental stage per se rather than level of hormone output dictates coordinate GnRH-LH/FSH-testosterone secretion. In summary, in eugonadal boys, the regularity of 24-h LH and testosterone secretory patterns undergoes well defined pubertal stage-specific control. No sexually developmentally delimited regulation is inferable for FSH. The concept of temporally biphasic puberty-dependent variations in neurohormone secretory regularity contrasts with the unidirectional rise in daily hormone output. Accordingly, we infer that late prepuberty and early puberty (Tanner genital stages IC and II) embody a physiologically unique sexual developmental window, marked by transiently enhanced LH and testosterone feedback stability in boys. Whether analogous plasticity of hypothalamo-pituitary-gonadal interactions unfolds during female adolescence is not known.

Diurnal rhythms of luteinizing hormone, follicle-stimulating hormone, testosterone, and estradiol secretion before the onset of female puberty in short children

To investigate hormonal changes before the onset of female puberty, we measured LH and FSH in serum samples drawn every 20 min for 24 h and measured testosterone and estradiol hourly for 24 h. Seventeen girls (13 prepubertal and 4 early pubertal) of short stature, from 5.1-11.4 yr of age, participated in this study. LH and FSH were measured using a time-resolved immunofluorometric assay, and testosterone and estradiol were measured using a sensitivity RIA capable of detecting testosterone and estradiol concentrations of 10 and 2 pg/mL, respectively. Diurnal rhythms of LH, FSH, and testosterone were apparent in all subjects, including those aged 5-6 yr. Serum LH and FSH concentrations showed night-day variation in a pulsatile fashion. The serum testosterone concentration was elevated in the early morning in all subjects. The serum estradiol concentration was elevated in the early morning in 4 of 13 prepubertal subjects and all 4 early pubertal subjects. The diurnal pattern of the serum estradiol concentration was similar to that of the serum testosterone concentration. Mean 24-h LH and testosterone concentrations in prepubertal subjects who did not attain puberty for at least 1 yr were 0.07 U/L and 65 pg/mL, respectively, whereas those in prepubertal subjects who attained puberty within 1 yr (0.14 U/L and 106 pg/mL, respectively) were significantly higher. Furthermore, mean 24-h LH, FSH, testosterone, and estradiol concentrations increased with the onset of puberty. In conclusion, the diurnal rhythms of LH, FSH, and testosterone already exist at 5-6 yr of age, and serum LH and testosterone levels increase before the onset of puberty. These results suggest that preparation for the onset of female puberty may begin in 5- to 6-yr-old girls.

Diurnal rhythms of luteinizing hormone, follicle-stimulating hormone, and testosterone secretion before the onset of male puberty

To investigate hormonal change before the onset of male puberty, we measured LH and FSH in serum samples drawn every 20 min for 24 h and measured testosterone hourly for 24 h. Forty-six boys (32 prepubertal and 14 pubertal) of short stature, between 4.4-19.3 yr of age, participated in this study. LH and FSH were measured using a time-resolved immunofluorometric assay, and testosterone was measured using high sensitivity RIA capable of detecting a testosterone concentration of 0.01 ng/mL. Diurnal rhythms of LH, FSH, and testosterone were apparent in all subjects, including those aged 4-5 yr. Serum LH and FSH concentrations showed night-day variation in a pulsatile fashion. The serum testosterone concentration was elevated at early morning in all subjects. Mean 24-h LH, FSH, and testosterone concentrations of prepubertal subjects who did not attain puberty for at least 3 yr were 0.10 U/L, 0.63 U/L, and 0.06 ng/mL, respectively, whereas those of prepubertal subjects who attained puberty within 1 yr (0.54 U/L, 1.68 U/L, and 0.10 ng/mL, respectively) were significantly higher. Furthermore, mean 24-h LH, FSH, and testosterone concentrations increased with developing puberty. All of the 46 subjects showed positive cross-correlation between the LH and testosterone time series. The mean lag time from the LH to the testosterone time series in the prepubertal subjects who attained puberty within 1 yr (4.7 +/- 2.4 h, mean +/- SD) was shorter than that in the prepubertal subjects who attained puberty after at least 3 yr (7.3 +/- 2.2 h). This lag time decreased with developing puberty, plateauing at 1.4 +/- 0.9 h at midpuberty. Thus, the diurnal rhythms of LH, FSH, and testosterone already exist at 4-5 yr of age; serum LH, FSH, and testosterone levels increase before the onset of puberty; and a time delay is observed between the LH and testosterone time series that decreases before the onset of puberty.

Ultralente insulin treatment of transient neonatal diabetes mellitus

In an infant with transient neonatal diabetes mellitus, control of the blood glucose concentration was attained with ultralente insulin treatment, without any episodes of hypoglycemia. We recommend subcutaneous injection of ultralente insulin, rather than lente or isophane (NPH) insulin, to avoid hypoglycemia during the treatment of transient neonatal diabetes mellitus.

Hashimoto encephalopathy: etiologic considerations

A 15-year-old girl is described with encephalopathy associated with Hashimoto thyroiditis which subsequently developed into autoimmune thyrotoxicosis (hashitoxicosis) and distal renal tubular acidosis at age 5 years, pernicious anemia at age 9, and encephalopathy at age 12. Thyroid hormone levels were within the normal ranges at the time of neurologic presentation. Serum IgG concentration and oligoclonal IgG bands in cerebrospinal fluid closely correlated with the severity of neurologic symptoms. Treatment with glucocorticoids improved the level of consciousness but her mental state continued to deteriorate. Repeated cranial computed tomographic scans revealed progressive symmetric atrophy in the gray matter without infarction. These findings suggest that encephalopathy associated with Hashimoto thyroiditis is caused by an antineuronal antibody-mediated reaction.

Hashimoto thyroiditis, distal renal tubular acidosis, pernicious anaemia and encephalopathy: a rare combination of auto-immune disorders in a 12-year-old girl

A case of a 12-year-old girl with a multiple auto-immune disorder is reported. She showed Hashimoto thyroiditis which subsequently developed to hashitoxicosis and distal renal tubular acidosis at 5 years of age, pernicious anaemia at the age of 9 and severe encephalopathy at the age of 12. Laboratory studies revealed very high titres of anti-microsomal and anti-thyroglobulin antibodies and positive gastric parietal cell antibody. As to the encephalopathy, positive oligoclonal IgG bands and high values of IgG index and IgG synthesis ratio in CSF were observed with aggravation of her neurological symptoms. High-dose steroid therapy was effective toward the encephalopathy. Paediatricians should pay careful attention to patients with Hashimoto thyroiditis for association with other autoimmune disorders.

Growth hormone secretory status in patients with Turner syndrome

The growth hormone (GH) secretory capacities in patients with Turner syndrome aged 5.1-15.9 years and those with constitutional short stature (CSS) aged 5.2-14.2 years were evaluated by pharmacological and physiological means. The GH response to hypoglycemia in the patients with Turner syndrome was lower than that in the patients with CSS. However, the GH response to arginine was not significantly different between the two patient groups. For the physiological test, the integrated concentration of GH (ICGH), the number of episodic peaks and their mean height were evaluated using blood obtained from the patients every 20 minutes for a period of 24 hours. The ICGH and the mean height of the episodic peaks in the patients with Turner syndrome were significantly lower than those in the CSS patients during the night but not during the day. Negative correlation between the bone age and the night-time values of ICGH was observed in the patients with Turner syndrome. Such correlation was not observed in the CSS patients. The patients with CSS showed a significant day-night difference in the ICGH and the mean height of the episodic peaks, but the patients with Turner syndrome did not show any significant day-night difference in either the ICGH or the mean height of episodic peaks. In conclusion, the GH secretory capacity in patients with Turner syndrome is lower than that in CSS patients.

Sonographic imaging of the thyroid gland in congenital hypothyroidism

We have attempted to facilitate differential diagnosis of etiological types of congenital hypothyroidism using real-time ultrasonography. Sonography of the thyroid gland was performed on 418 normal children, and 23 patients with congenital hypothyroidism and hyperthyrotropinemia. The thyroid gland was imaged by transverse scanning at the neck; the maximum thickness and the maximum width of the right and left lobe were measured. On the basis of the normal thyroid gland size obtained from normal children, the thyroid gland image of the patients were classified into 4 types: large image, normal image, small image, and no image of the thyroid gland at the neck: no image of the thyroid gland indicated agenesis or ectopia; large thyroid gland image indicated goitorous hypothyroidism. On the other hand, normal or small thyroid gland image probably included mild or transient forms of hypothyroidism, and transient hyperthyrotropinemia; these 2 types required further examination to complete the diagnosis. We concluded that real-time ultrasonography of the thyroid gland was a useful diagnostic imaging technic for patients who revealed elevated serum thyrotropin on neonatal mass-screening.