In a mouse model of pneumococcal meningitis, skull channels provide extravascular signaling to the skull marrow capable of initiating local marrow hematopoiesis.
View Article and Find Full Text PDFThe intestine is the home to the largest number of immune cells in the body. The small and large intestinal immune systems police exposure to exogenous antigens and modulate responses to potent microbially derived immune stimuli. For this reason, the intestine is a major target site of immune dysregulation and inflammation in many diseases including but, not limited to inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, graft-versus-host disease (GVHD) after bone marrow transplantation (BMT), and many allergic and infectious conditions.
View Article and Find Full Text PDFAm J Physiol Endocrinol Metab
November 2018
Estrogens regulate normal sexual and reproductive development in females. Their actions are mediated mainly by estrogen receptor (ER)α and ERβ. Understanding the function of ERs necessitates knowing their cellular location and protein partners, which, in turn, requires reliable and specific antibodies.
View Article and Find Full Text PDFEarly in the pathogenesis of type 2 diabetes mellitus (T2DM), dysregulated glucagon secretion from pancreatic α cells occurs prior to impaired glucose-stimulated insulin secretion (GSIS) from β cells. However, whether hyperglucagonemia is causally linked to β cell dysfunction remains unclear. Here we show that glucagon stimulates via cAMP-PKA-CREB signaling hepatic production of the neuropeptide kisspeptin1, which acts on β cells to suppress GSIS.
View Article and Find Full Text PDFLandmark studies have shown that mutations in kisspeptin and the kisspeptin receptor (Kiss1r) result in reproductive dysfunction in humans and genetically altered mouse models. However, because kisspeptin and its receptor are present in target cells of the central and peripheral reproductive axis, the precise location(s) for the pathogenic signal is unknown. The study described herein shows that the kisspeptin-Kiss1r signaling pathway in the GnRH neuron is singularly critical for both the onset of puberty as well as the attainment of normal reproductive function.
View Article and Find Full Text PDFAlthough sex steroids have been implicated in the control of mammalian growth, their direct effect on GH synthesis is less clear. The aim of this study was to establish whether estradiol (E2) directly affects GH synthesis in somatotrophs. Somatotroph GH3 and MtT/S cells were used as in vitro models.
View Article and Find Full Text PDFKisspeptins (Kiss) have been shown to be key components in the regulation of gonadotropin-releasing hormone (GnRH) secretion. In vitro studies have demonstrated an increase in GnRH gene expression by Kiss suggesting regulation of GnRH at both the secretory and pretranslational levels. Here, we define genetic mechanisms that mediate Kiss action on target gene expression.
View Article and Find Full Text PDFAppropriate tissue-specific gene expression of gonadotropin-releasing hormone (GnRH) is critical for pubertal development and maintenance of reproductive competence. In these studies, a common element in the mouse GnRH (mGnRH) promoter, between -2806 and -2078 bp, is shown to mediate differential regulation of hypothalamic and ovarian mGnRH expression. To further characterize this region, we generated a knock-out mouse (GREKO(-/-)) with a deletion of the mGnRH promoter fragment between -2806 and -2078 bp.
View Article and Find Full Text PDFBackground/aims: Mutations in the thyroid hormone receptor beta (TR-beta) gene result in resistance to thyroid hormone (RTH). Mutation Delta337T in the TR-beta gene has been shown to have the characteristics of RTH syndrome in mice. The aim of this work was to study the possible involvement of TR-beta receptor in thyroid modulation of ClC-2 in mouse kidney.
View Article and Find Full Text PDFMol Cell Endocrinol
November 2009
Kisspeptins, and their G-protein coupled receptor 54 (GPR54), are key components in the regulation of gonadotropin-releasing hormone (GnRH) secretion in humans and other mammals. Several studies demonstrate that the central or systemic administration of kisspeptin increases GnRH and gonadotropin secretion in both prepubertal and adult animals; however, the cellular targets and intracellular mechanisms of action in the central reproductive axis are unclear. In this study, we documented the presence of GPR54 in two GnRH secreting neuronal cell lines (GT1-7 and GN11).
View Article and Find Full Text PDFEstrogen plays an essential role in the regulation of the female reproductive hormone axis, and specifically is a major regulator of GnRH neuronal function in the female brain. GnRH neuronal cell lines were used to explore the direct effects of estradiol on gene expression in GnRH neurons. The presence of estrogen receptor (ER) binding sites was established by a receptor-binding assay, and estrogen receptor alpha and beta mRNA were identified in GN11 cells and ERbeta in GT1-7 cells using RT-PCR analysis of mRNA.
View Article and Find Full Text PDFTNR-CFTR, discovered as a splice variant of CFTR (Cystic Fibrosis Transmembrane conductance Regulator), is distributed in different tissues such as human and rat kidney, trachea, lungs etc and is a functional chloride channel. In Kidneys, our findings show TNR-CFTR to have an unique distribution pattern with low levels of expression in renal cortex and high levels of expression in renal medulla. As shown by us previously, TNR-CFTR mRNA lacks 145 bp corresponding to segments of exons 13 and 14.
View Article and Find Full Text PDFCFTR is a multifunctional protein of the ATP binding cassette family that may contribute to overall electrolyte homeostasis by acting as a chloride channel in the kidney. In renal tissues CFTR does not exists only in its full-length form, but also as a kidney-specific, truncated splice variant, TNR-CFTR. In this study we show that both forms of CFTR are regulated by thyroid hormones in rat renal tissue.
View Article and Find Full Text PDFIn this work, we studied the mRNA distribution of CNG-A3, an amiloride-sensitive sodium channel that belongs to the cyclic nucleotide-gated (CNG) family of channels, along the rat nephron. The possible involvement of aldosterone in this process was also studied. We also evaluated its expression in rats subjected to diets with different concentrations of sodium or to alterations in aldosterone plasma levels.
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