Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0728731 (prematurity)
 7,134 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A competent permeability barrier must be present by the end of gestation to allow for life in a terrestrial environment. Indeed, early preterm infants display serious complications of skin immaturity. Yet, regardless of their degree of prematurity, all infants quickly develop a competent barrier. To learn more about the mechanisms and regulation of barrier ontogeny, we have utilized late-gestation fetal rodents. In 19-21 d fetal rats, we showed that barrier competence is accompanied by both enhanced epidermal development and formation of extracellular lamellar membranes in the stratum corneum. The identical sequence and time-course occurs when fetal rat skin is cultured in a serum-free medium. Glucocorticoids, thyroid hormone (T3), and estrogen accelerate, while androgens delay barrier formation both in utero and in the in vitro system, explaining the poorer outcome of premature males versus females. But neither T3 nor glucocorticoids are absolutely required for barrier development. Lifting fetal skin cultures to an air-medium interface also accelerates barrier formation, explaining the rapid emergence of barrier competence in very premature infants. PPARalpha and FXR activators, which, like T3, heterodimerize with the nuclear receptor, RXR, also accelerate barrier development in vitro. Finally, not only the nuclear receptor family, but also Ca++ could regulate key events late in barrier development.
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PMID:Ontogeny of the epidermal permeability barrier. 973 18

Although the lung is a defining feature of air-breathing animals, the pathway controlling the formation of type I pneumocytes, the cells that mediate gas exchange, is poorly understood. In contrast, the glucocorticoid receptor and its cognate ligand have long been known to promote type II pneumocyte maturation; prenatal administration of glucocorticoids is commonly used to attenuate the severity of infant respiratory distress syndrome (RDS). Here we show that knock-in mutations of the nuclear co-repressor SMRT (silencing mediator of retinoid and thyroid hormone receptors) in C57BL/6 mice (SMRTmRID) produces a previously unidentified respiratory distress syndrome caused by prematurity of the type I pneumocyte. Though unresponsive to glucocorticoids, treatment with anti-thyroid hormone drugs (propylthiouracil or methimazole) completely rescues SMRT-induced RDS, suggesting an unrecognized and essential role for the thyroid hormone receptor (TR) in lung development. We show that TR and SMRT control type I pneumocyte differentiation through Klf2, which, in turn, seems to directly activate the type I pneumocyte gene program. Conversely, mice without lung Klf2 lack mature type I pneumocytes and die shortly after birth, closely recapitulating the SMRTmRID phenotype. These results identify TR as a second nuclear receptor involved in lung development, specifically type I pneumocyte differentiation, and suggest a possible new type of therapeutic option in the treatment of RDS that is unresponsive to glucocorticoids.
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PMID:Thyroid hormone receptor repression is linked to type I pneumocyte-associated respiratory distress syndrome. 2200 6

Maternal thyroid hormones (THs) are essential for normal offspring's neurodevelopment even after onset of fetal thyroid function. This is particularly relevant for preterm children who are deprived of maternal THs following birth, are at risk of suffering hypothyroxinemia, and develop attention-deficit/hyperactivity disorder. Expression of neocortical Ca(2+)/calmodulin kinase IV (Camk4), a genomic target of thyroid hormone, and nuclear receptor-related 1 protein (Nurr1), a postnatal marker of cortical subplate (SP) cells, was studied in euthyroid fetuses and in pups born to dams thyroidectomized in late gestation (LMH group, a model of prematurity), and compared with control and developmentally hypothyroid pups (C and MMI groups, respectively). In LMH pups, the extinction of heavy Camk4 expression in an SP was 1-2 days delayed postnatally compared with C pups. The heavy Camk4 and Nurr1 expression in the SP was prolonged in MMI pups, whereas heavy Camk4 and Nurr1 expression in layer VIb remains at P60. The abnormal expression of Camk4 in the cortical SP and in layer VIb might cause altered cortical connectivity affecting neocortical function.
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PMID:Late maternal hypothyroidism alters the expression of Camk4 in neocortical subplate neurons: a comparison with Nurr1 labeling. 2368 Aug 40