Transcriptome analyses of ovarian stroma: tunica albuginea, interstitium and theca interna.

The ovary has specialised stromal compartments, including the tunica albuginea, interstitial stroma and theca interna, which develops concurrently with the follicular antrum. To characterise the molecular determinants of these compartments, stroma adjacent to preantral follicles (pre-theca), interstitium and tunica albuginea were laser microdissected (n = 4 per group) and theca interna was dissected from bovine antral follicles (n = 6). RNA microarray analysis showed minimal differences between interstitial stroma and pre-theca, and these were combined for some analyses and referred to as stroma. Genes significantly upregulated in theca interna compared to stroma included INSL3, LHCGR, HSD3B1, CYP17A1, ALDH1A1, OGN, POSTN and ASPN. Quantitative RT-PCR showed significantly greater expression of OGN and LGALS1 in interstitial stroma and theca interna versus tunica and greater expression of ACD in tunica compared to theca interna. PLN was significantly higher in interstitial stroma compared to tunica and theca. Ingenuity pathway, network and upstream regulator analyses were undertaken. Cell survival was also upregulated in theca interna. The tunica albuginea was associated with GPCR and cAMP signalling, suggesting tunica contractility. It was also associated with TGF-ß signalling and increased fibrous matrix. Western immunoblotting was positive for OGN, LGALS1, ALDH1A1, ACD and PLN with PLN and OGN highly expressed in tunica and interstitial stroma (each n = 6), but not in theca interna from antral follicles (n = 24). Immunohistochemistry localised LGALS1 and POSTN to extracellular matrix and PLN to smooth muscle cells. These results have identified novel differences between the ovarian stromal compartments.

Biological and dosimetric characterisation of spatially fractionated proton minibeams.

The biological effectiveness of proton beams varies with depth, spot size and lateral distance from the beam central axis. The aim of this work is to incorporate proton relative biological effectiveness (RBE) and equivalent uniform dose (EUD) considerations into comparisons of broad beam and highly modulated proton minibeams. A Monte Carlo model of a small animal proton beamline is presented. Dose and variable RBE is calculated on a per-voxel basis for a range of energies (30-109 MeV). For an open beam, the RBE values at the beam entrance ranged from 1.02-1.04, at the Bragg peak (BP) from 1.3 to 1.6, and at the distal end of the BP from 1.4 to 2.0. For a 50 MeV proton beam, a minibeam collimator designed to produce uniform dose at the depth of the BP peak, had minimal impact on the open beam RBE values at depth. RBE changes were observed near the surface when the collimator was placed flush with the irradiated object, due to a higher neutron contribution derived from proton interactions with the collimator. For proton minibeams, the relative mean RBE weighted entrance dose (RWD) was ~25% lower than the physical mean dose. A strong dependency of the EUD with fraction size was observed. For 20 Gy fractions, the EUD varied widely depending on the radiosensitivity of the cells. For radiosensitive cells, the difference was up to ~50% in mean dose and ~40% in mean RWD and the EUD trended towards the valley dose rather than the mean dose. For comparative studies of uniform dose with spatially fractionated proton minibeams, EUD derived from a per-voxel RWD distribution is recommended for biological assessments of reproductive cell survival and related endpoints.

Molecular genetics of the developing neuroendocrine hypothalamus.

Formation of the mammalian endocrine system and neuroendocrine organs involves complex regulatory networks resulting in a highly specialized cell system able to secrete a diverse array of peptide hormones. The hypothalamus is located in the mediobasal region of the brain and acts as a gateway between the endocrine and nervous systems. From an endocrinology perspective, the parvicellular neurons of the hypothalamus are of particular interest as they function as a control centre for several critical physiological processes including growth, metabolism and reproduction by regulating hormonal signaling from target cognate cell types in the anterior pituitary. Delineating the genetic program that controls hypothalamic development is essential for complete understanding of parvicellular neuronal function and the etiology of congenital disorders that result from hypothalamic-pituitary axis dysfunction. In recent years, studies have shed light on the interactions between signaling molecules and activation of transcription factors that regulate hypothalamic cell fate commitment and terminal differentiation. The aim of this review is to summarize the recent molecular and genetic findings that have advanced our understanding of the emergence of the known important hypophysiotropic signaling molecules in the hypothalamus. We have focused on reviewing the literature that provides evidence of the dependence on expression of specific genes for the normal development and function of the cells that secrete these neuroendocrine factors, as well as studies of the elaboration of the spatial or temporal patterns of changes in gene expression that drive this development.

Sexually dimorphic effects of maternal alcohol intake and adrenalectomy on left ventricular hypertrophy in rat offspring.

In humans, low birth weight and increased placental weight can be associated with cardiovascular disease in adulthood. Low birth weight and increased placental size are known to occur after fetal alcohol exposure or prenatal glucocorticoid administration. Thus the effects of removing the alcohol-induced increase in maternal corticosterone by maternal adrenalectomy on predictors of cardiovascular disease in adulthood were examined in rats. Alcohol exposure of dams during the last 2 wk of gestation resulted in significantly decreased fetal weight and increased placental weight on gestational day 21. Adult female, but not male, offspring of alcohol-consuming mothers exhibited left ventricular hypertrophy. Placental 11beta-hydroxysteroid dehydrogenase-2 (11beta-HSD-2) mRNA levels, measured by Northern blot, were decreased in females but not males. Adrenalectomy of alcohol-consuming dams reversed the increase in placental weight and the decrease in female placental 11beta-HSD-2 expression and eliminated the left ventricular hypertrophy of adult female offspring. These data suggest that alcohol-induced changes in placental 11beta-HSD-2 mRNA levels and left ventricular weight are coupled in female offspring only and depend on maternal adrenal status.

Differential effects of the early and late intrauterine environment on corticotrophic cell development.

The developing embryo and fetus respond to a range of intrauterine stressors, but the effect of chronic intrauterine stress on the programmed development of pituitary corticotrophs has not been investigated. We have used a pregnant sheep model in which the embryonic environment at conception has been surgically perturbed by uterine carunclectomy. This procedure results in the development of fetuses that either are placentally restricted and chronically hypoxemic or that demonstrate compensatory placental growth and maintain normoxemia throughout late gestation. We found that uterine carunclectomy resulted in the emergence of a population of non-corticotrophin-releasing hormone (non-CRH) target cells that secreted high amounts of adrenocorticotrophic hormone (ACTH) in the fetal pituitary. This change in corticotroph development was independent of late-gestation hypoxemia. However, chronic hypoxemia during late gestation (in either carunclectomized or non-carunclectomized uterine environments) resulted in a reduction in the proportion of ACTH stored in CRH-target. Thus, the early and late intrauterine environments differentially program the development of specific corticotrophic cell types in the fetal pituitary. These patterns of altered corticotroph development are important given the central roles of the hypothalamo-pituitary-adrenal axis in the fetal adaptive response to intrauterine stress and in the early programming of adult disease.