Corpuscle Of Stannius Research Articles

Cadherin 16 promotes sensory gating via the endocrine corpuscles of Stannius.

Sensory thresholds enable animals to regulate their behavioral responses to environmental threats. Despite the importance of sensory thresholds for animal behavior and human health, we do not yet have a full appreciation of the underlying molecular-genetic and circuit mechanisms. The larval zebrafish acoustic startle response provides a powerful system to identify molecular mechanisms underlying establishment of sensory thresholds and plasticity of thresholds through mechanisms like habituation. Using this system, we identify Cadherin 16 as a previously undescribed regulator of sensory gating. We demonstrate that Cadherin 16 regulates sensory thresholds via an endocrine organ, the corpuscle of Stannius (CS), which is essential in zebrafish for regulating Ca2+ homeostasis. We further show that Cadherin 16 regulates whole-body calcium and ultimately behavior through the hormone Stanniocalcin 1L, and the IGF-regulatory metalloprotease, Papp-aa. Finally, we demonstrate the importance of the CS through ablation experiments that reveal its role in promoting normal acoustic sensory gating. Together, our results uncover a previously undescribed brain non-autonomous pathway for the regulation of behavior and establish Ca2+ homeostasis as a critical process underlying sensory gating in vivo.

EF-hand domain containing 2 (Efhc2) is crucial for distal segmentation of pronephros in zebrafish

BackgroundThe blood filtering organ in zebrafish embryos is the pronephros, which consists of two functional nephrons. Segmentation of a nephron into different domains is essential for its function and is well conserved among vertebrates. Zebrafish has been extensively used as a model to understand nephron segmentation during development. Here, we have identified EF-hand domain containing 2 (Efhc2) as a novel component of genetic programme regulating nephron segmentation in zebrafish. Human EFHC2 is a protein with one predicted calcium-binding EF-hand motif and three DM10 domains, whose function is unknown. EFHC2 has been implicated in several brain-related genetic diseases like Turner syndrome and juvenile myoclonic epilepsy. However, there is limited information on its normal physiological function.Resultsefhc2 mRNA is primarily expressed in the pronephros of zebrafish embryos. Other sites of expression include olfactory placode, notochord, otic vesicle, epiphysis and neuromast cells. Morpholino antisense oligonucleotide-mediated knock-down of Efhc2 resulted in defects in pronephros development and function in zebrafish embryos. Efhc2 knock-down leads to expansion of distal early segment of pronephros, whereas, the corpuscle of stannius and distal late segments were reduced. The number of multi-ciliated cells (MCC) that are present in a salt-and-pepper fashion throughout the middle of each nephron and vital for fluid flow were also reduced. It is known that retinoic acid (RA) signaling regulates pronephros segmentation in vertebrates and we show that Efhc2 function is crucial for nephron segmentation in zebrafish. Our data suggests that RA and Efhc2 function independent of each other in pronephros segmentation. However, Efhc2 and RA synergistically regulate MCC development.ConclusionIn this study, we have identified Efhc2 as a regulator of segmentation of the distal part of nephron and pronephros function during zebrafish development.

The expression of natriuretic peptide receptors in developing zebrafish embryos

There are three isoforms of natriuretic peptide (NP) specific cell surface receptor: NP receptor-A (NPRA), receptor-B (NPRB), and receptor-C (NPRC). They are also known as NPR1, NPR2 and NPR3, respectively. NPs and their receptors were revealed to involve in diverse cellular and physiological processes including renal, cardiovascular, neuronal, and immunological aspects. However, the systematic analysis of the expression of these receptors in non-mammalian vertebrates is thus far lacking. In this study, two versions of the npr1 gene (npr1a and npr1b) in zebrafish was identified. Multiple sequences alignment analysis showed that zebrafish NPRs shared high homologies with NPRs of other species and possessed a typical signature domain of NPRs. The results of whole mount in situ hybridization and reverse transcription polymerase chain reaction analysis revealed that at embryonic stages, npr1a was mainly expressed in tectal ventricle, brian, heart and retina, whereas npr1b was broadly present in anterior pronephric duct. Unlike npr1, npr2 mainly expressed in branchial arches and neural tube during embryonic development. However, npr3 was expressed in pronephric ducts and corpuscle of stannius in zebrafish embryos at 72 hpf. In adults, we demonstrated that all the three NP receptors were highly existed in brain and kidney. Overall, these findings will provide an important basis for the functional analysis of NPs and its receptor during embryonic development.

Activation of gill Ca2+-sensing receptor as a protective pathway to reduce Ca2+-induced cytotoxicity.

The expression of the Ca(2) (+)-sensing receptor (Casr) in the endocrine gland known as the corpuscle of Stannius (CS) regulates the secretion of the hypocalcemic hormone stanniocalcin-1 (STC1) to inhibit gill Ca(2) (+) uptake. Although numerous studies have reported the branchial expression of Casr and Stc1, the functions of these proteins in gills have not been elucidated yet. On the basis of recent findings regarding the autocrine/paracrine functions of STC1 in mammalian models, we proposed the hypothesis that branchial CaSR has an in situ 'sensing' function to regulate STC1 that maintains local Ca(2) (+) homeostasis. In this study, we investigated Casr-mediated signaling and its regulation of Stc1 and cyclooxygenase-2 (Cox2) expression/function using a primary gill-cell culture model. The biochemical responses of gill cells isolated from Japanese eels to an increasing concentration of extracellular Ca(2) (+) (0.1-1 mM) were tested. This stimulation led to a transient increase in phosphatidylcholine-phospholipase C (PC-PLC) activity, followed by activation of ERK and inositol 1,4,5-trisphosphate-Ca(2) (+)/calmodulin-dependent protein kinase 2 (CaMK2) signaling pathways. Cotreatment with the calcimimetic R467 caused synergistic effects on Ca(2) (+)-stimulated PC-PLC activity, ERK signaling, and CaMK2 signaling. The activation of the CaSR-PLC-ERK pathway was associated with increased expression levels of Stc1 and Cox2 as confirmed by the inhibition of Erk using a chemical inhibitor, PD98059. Functionally, Ca(2) (+)/R-467 pretreatment was found to protect cells from thapsigargin-induced cell death. Inhibition of COX2 activity using NS398 abolished this protection, while transduction of STC1 lentiviral particles in the gill cells increased the protective effects. Collectively, our data revealed the expression of functional CaSR in gill tissues. The identification of the CaSR-STC1/COX2-mediated protective pathway in gill cells sheds light on a possible cellular protective mechanism against an increase in intracellular Ca(2) (+) levels associated with transepithelial Ca(2) (+) transport.

The Pathological Effects of Melamine and Cyanuric Acid in the Diet of Walking Catfish (Clarius batrachus)

The toxicity of melamine and its analogue in man and animals has been reported widely. The aim of the present study was to examine the pathological effects of feeding melamine and cyanuric acid, separately or in combination, to walking catfish (Clarius batrachus). The catfish developed darkening of the skin as early as 3 days post feeding. Melamine-related crystals were distributed multifocally throughout the liver, kidney, heart, spleen and corpuscle of Stannius of fish fed melamine and cyanuric acid in combination. Oil red O staining and electron microscopy revealed that the melamine-related crystals had structure resembling that of plastic polymer crystals. Elevations in the serum concentrations of alanine transaminase, aspartate transaminase, creatinine and uric acid were related to the crystal-associated granulomatous inflammation in the liver and kidney of affected fish. None of the catfish died during the 2-week experiment. Melamine and cyanuric acid are therefore systemically toxic to fish in addition to causing renal crystal formation and renal damage as seen in man and animals. The finding of extrarenal crystals implies that the metabolism and biotransformation of these toxic compounds should be further investigated in aquatic animals.

Mammalian stanniocalcins and cancer.

Stanniocalcin (STC) is a glycoprotein hormone that is secreted by the corpuscle of Stannius, an endocrine gland of bony fish, and is involved in calcium and phosphate homeostasis. The related mammalian proteins, STC1 and STC2, are expressed in a wide variety of tissues. The ovaries have the highest level of STC1, and this increases during pregnancy and lactation. STC1 is present in breast ductal epithelium, and its expression is induced by BRCA1, a tumor suppressor gene that has an important role in breast and ovarian cancer. The expression of STC2 is induced by estrogen, and there is a positive correlation between the level of expression of estrogen receptor and expression of both STC1 and STC2 in breast cancer. This article reviews the data currently available regarding the mammalian STCs, and discusses the roles they may play in normal physiology and in breast and other cancers.

Human Stanniocalcin (STC): Genomic Structure, Chromosomal Localization, and the Presence of CAG Trinucleotide Repeats

Stanniocalcin (STC) is a glycoprotein hormone that is secreted by the corpuscle of Stannius, an endocrine gland of bony fish. It prevents hypercalcemia via mechanisms including inhibition of calcium uptake across the gills. Mammalian homologues have recently been reported but their function is unknown. Here we report the genomic organization and the transcription start site of the human STC gene and the existence of a polymorphic CAG trinucleotide repeat complex within the 5′ untranslated region (UTR) of the mRNA and a smaller [CAG]6repeat in the 3′ UTR. As CAG repeats are associated with various human diseases, we used dual-color fluorescencein situhybridization to localize the STC gene near markers D8S131 and D8S339 on chromosome 8p11.2–p21. STC should be considered a candidate gene for hereditary diseases mapped to this region.

A histological study on the endocrine and exocrine glands of fish by Bowie's stain.

Using Bowie's and other staining methods, histological examinations were made on seven kinds of endocrine and three kinds of exocrine glands of fish, and the fbllowing results were obtained. Bowie's method is recommended for demonstration of the cellular secretorty granules in BROCKMANN body, corpuscle of STANNIUS, renal juxtaglomerular cells, pancreatic acinar cells, and gastric zymogenie cells. Use of this method for differentiation gave excellent results in the secretory granules of A-and B-cells of Brockmann body. Furthermore, Bowie's method is suitable for staining the neuro-secretory inclusion in the preoptic neurosecretory cells, STH-and ACTH-cells of pituitary gland, and also colloid in the lumen of thyroid follicle. However, this method is not applicable for staining the chromaffin and interrenal cells of the adrenal gland, cells of uitimobranchial gland, and also the epidermal mucous cells of fish skin.

Changes in the corpuscle of Stannius during the spawning journey of Atlantic salmon ( Salmo salar)

In an effort to clarify the function of the corpuscle of Stannius in Atlantic salmon ( Salmo salar), histological studies were made of specimens from Canadian fish taken at various stages in the spawning journey. The general architecture and cell types of the corpuscle changed in several ways; these were more closely related to time in fresh water than to gonadal development. An anatomical unit composed of ganglion cells, nerves, and thick-walled blood vessels was consistently noted between the corpuscle and adjacent renal tissue. The relation of these observations to the overall function of the teleostean kidney with its several mechanisms for homeostatic control of electrolytes and steroid activity is briefly discussed.

Structure of the Corpuscle of Stannius in Normal and Radiothyroidectomized Chinook Fingerlings and Spawning Pacific Salmon

Structure of the Corpuscle of Stannius in Normal and Radiothyroidectomized Chinook Fingerlings and Spawning Pacific Salmon

The development and phylogeny of the corpuscle of stannius in ganoid and teleostean fishes

The development and phylogeny of the corpuscle of stannius in ganoid and teleostean fishes