A rare arterial branch distributing to the thymus, ectopic intrathymic parathyroid, and thyroid glands which passed ventral to the right common carotid artery: a case report.

The intrathymic parathyroid has been reported that this variation might be related with the hyperthyroidism. In this study, the arterial pattern supplying the intrathymic parathyroid was examined in detail in the human cadaver (67-year-old, female, right side). The ectopic parathyroid was only detected on the right side, but not on the left side. This ectopic intrathymic parathyroid was supplied by the supernumerary arterial branch that originated from the inferior thyroid artery and passed ventral to the common carotid artery. This supernumerary branch further divided into two thin branches: (1) the one distributing the intrathymic parathyroid and the right lobe of the thyroid gland and (2) the other descending toward the thoracic cavity to supply the mediastinum organs. Other arteries supplying the thyroid gland and thymus of both sides were normal. In the surgical resection of the ectopic intrathymic parathyroid, physicians should pay attention to arteries ventral to the common carotid artery. This supernumerary branch distributing to the intrathymic parathyroid may be caused by incomplete division into the primordium for the inferior parathyroid and the primordium for the thymus on the developmental process.

Promotion of colorectal cancer invasion and metastasis through activation of NOTCH-DAB1-ABL-RHOGEF protein TRIO.

UNLABELLED: We have recently identified a metastasis suppressor gene for colorectal cancer: AES/Aes, which encodes an endogenous inhibitor of NOTCH signaling. When Aes is knocked out in the adenomatous epithelium of intestinal polyposis mice, their tumors become malignant, showing marked submucosal invasion and intravasation. Here, we show that one of the genes induced by NOTCH signaling in colorectal cancer is DAB1/Dab1. Genetic depletion of DAB1 suppresses cancer invasion and metastasis in the NOTCH signaling-activated mice. DAB1 is phosphorylated by ABL tyrosine kinase, which activates ABL reciprocally. Consistently, inhibition of ABL suppresses cancer invasion in mice. Furthermore, we show that one of the targets of ABL is the RAC/RHOGEF protein TRIO, and that phosphorylation at its Tyr residue 2681 (pY2681) causes RHO activation in colorectal cancer cells. Its unphosphorylatable mutation TRIO Y2681F reduces RHOGEF activity and inhibits invasion of colorectal cancer cells. Importantly, TRIO pY2681 correlates with significantly poorer prognosis of patients with colorectal cancer after surgery. SIGNIFICANCE: These results indicate that TRIO pY2681 is one of the downstream effectors of NOTCH signaling activation in colorectal cancer, and can be a prognostic marker, helping to determine the therapeutic modality of patients with colorectal cancer.

Function of strawberry notch family genes in the zebrafish brain development.

We previously reported embryonic expression pattern of strawberry notch (sbno) family genes, suggesting involvement in brain development. However function of sbno genes in the vertebrate development has not been known yet. Utilizing zebrafish embryos, we experimentally examined function of sbno genes during brain development in this report. Knockdown experiments of sbno1 and sbno2a disrupted brain morphology, and delayed developmental alteration of gene expression. The earliest effect of loss of function of sbno genes on the zebrafish embryogenesis that we found here was downregulation of otx2 expression. Knockdown of sbno1 specifically affects regionalization along the anterior-posterior axis of the brain. These results suggest essential roles of sbno genes in vertebrate brain development.

The transcriptional repressor RP58 is crucial for cell-division patterning and neuronal survival in the developing cortex.

The neocortex and the hippocampus comprise several specific layers containing distinct neurons that originate from progenitors at specific development times, under the control of an adequate cell-division patterning mechanism. Although many molecules are known to regulate this cell-division patterning process, its details are not well understood. Here, we show that, in the developing cerebral cortex, the RP58 transcription repressor protein was expressed both in postmitotic glutamatergic projection neurons and in their progenitor cells, but not in GABAergic interneurons. Targeted deletion of the RP58 gene led to dysplasia of the neocortex and of the hippocampus, reduction of the number of mature cortical neurons, and defects of laminar organization, which reflect abnormal neuronal migration within the cortical plate. We demonstrate an impairment of the cell-division patterning during the late embryonic stage and an enhancement of apoptosis of the postmitotic neurons in the RP58-deficient cortex. These results suggest that RP58 controls cell division of progenitor cells and regulates the survival of postmitotic cortical neurons.

Retrograde infection of precerebellar nuclei neurons by injection of a recombinant adenovirus into the cerebellar cortex of normal and reeler mice.

The reeler mouse is an autosomal recessive mutant mouse caused by mutation of the reelin gene and characterized by cerebellar ataxia. To determine whether the distribution pattern of precerebellar nuclei neurons in the brainstem of the reeler mouse changes, we injected a small volume of a replication-defective recombinant adenovirus carrying E. coli beta-galactosidase (lacZ) into the cerebellar cortex of normal and reeler mice. Five days later, the mice were transcardially perfused by a fixative solution. X-gal staining of coronal or sagittal sections of the brainstem revealed that many origins for reticulocerebellar, cuneocerebellar, trigeminocerebellar, and pontocerebellar projections were retrogradely labeled, but only a few olivocerebellar neurons were labeled. Retrogradely labeled neurons in the lateral reticular nucleus tended to locate more laterally and be more condensed into a small compartment in the reeler compared with their normal counterparts. Retrogradely labeled neurons in the external cuneate nucleus were more dorsally shifted in the reeler mice compared with their normal counterparts. We could not find any differences between the normal and reeler mice in the distribution patterns of their trigeminocerebellar projection neurons. Retrogradely labeled pontocerebellar neurons in the basilar pons of the reeler mouse were reduced in number compared with their normal counterparts in addition to being more ventrally and laterally shifted. These findings strongly suggest that the migration of some precerebellar nuclei neurons from the rhombic lip to their final loci may be obstructed in the reeler mice.

Bcl-2 expression mediated by Cre/loxP system in olfactory epithelium.

To study the Bcl-2 expression mediated by the Cre/loxP recombination system and its effect on prevention of apoptosis in olfactory epithelium. Adenoviral vectors with cassette for Bcl-2 (AxCALNLBcl-2) and Cre recombinase (AxCANCre) were applied to mouse olfactory epithelium by intranasal instillation. The effect of exogenous Bcl-2 expression on prevention of apoptosis of olfactory receptor neurons was investigated using an apoptosis model induced by bulbectomy. The Bcl-2 product was expressed not only in the olfactory receptor neurons but also in the supporting cells. Although statistical analysis did not show significant difference, the number of apoptotic cells in the infected olfactory epithelium on post-bulbectomy day 2 was lower than that of control and the number of survived mature olfactory receptor neurons in the infected olfactory epithelium on post-bulbectomy day 5 was higher than that of control. Although further studies are required for clinical application, the results of our study suggest that this strategy may be able to deliver exogenous Bcl-2 for the treatment of degeneration of olfactory receptor neurons.

Adenovirus-mediated gene transfer in olfactory epithelium and olfactory bulb: a long-term study.

OBJECTIVES: We sought to study the spatiotemporal gene expression mediated by adenoviral vector in the olfactory pathways. METHODS: The replication-defective adenoviral vector AxCALacZ, which encodes the enzyme Escherichia coli beta-galactosidase, was applied to mouse olfactory epithelium by intranasal instillation. RESULTS: The LacZ gene product, beta-galactosidase, was expressed not only in the olfactory receptor neurons and their axons, but also in the olfactory bulbs. The first evidence of anterograde labeling was observed at postinfection day (PID) 2. At PID 3, beta-galactosidase was strongly expressed in olfactory nerve axons, as well as their terminal glomeruli, in the olfactory bulbs. beta-Galactosidase expression persisted up to PID 90, and there was a significant decrease in the number of labeled neurons at PID 30. CONCLUSIONS: These results suggest possible long-term effects of adenovirus-mediated gene transfer on the olfactory neurons, as well as the olfactory bulbs.

Congenital semilunar valvulogenesis defect in mice deficient in phospholipase C epsilon.

Phospholipase Cepsilon is a novel class of phosphoinositide-specific phospholipase C, identified as a downstream effector of Ras and Rap small GTPases. We report here the first genetic analysis of its physiological function with mice whose phospholipase Cepsilon is catalytically inactivated by gene targeting. The hearts of mice homozygous for the targeted allele develop congenital malformations of both the aortic and pulmonary valves, which cause a moderate to severe degree of regurgitation with mild stenosis and result in ventricular dilation. The malformation involves marked thickening of the valve leaflets, which seems to be caused by a defect in valve remodeling at the late stages of semilunar valvulogenesis. This phenotype has a remarkable resemblance to that of mice carrying an attenuated epidermal growth factor receptor or deficient in heparin-binding epidermal growth factor-like growth factor. Smad1/5/8, which is implicated in proliferation of the valve cells downstream of bone morphogenetic protein, shows aberrant activation at the margin of the developing semilunar valve tissues in embryos deficient in phospholipase Cepsilon. These results suggest a crucial role of phospholipase Cepsilon downstream of the epidermal growth factor receptor in controlling semilunar valvulogenesis through inhibition of bone morphogenetic protein signaling.

Retrograde labeling of mouse spinal descending tracts by a recombinant adenovirus.

The present study tested whether a gene-transfer based upon the retrograde axonal transport of the lacZ adenovirus is effective in the spinal descending tracts of the adult mouse. A small volume of a replication-defective recombinant adenovirus encoding E. coli beta-galactosidase was injected into the upper lumbar cord, and, seven days later, the mice were transcardially perfused by a fixative solution. X-gal staining of coronal or sagittal sections of the spinal cord and the brain revealed that many sites of origin for rubrospinal, vestibulospinal, and reticulospinal tracts were retrogradely labeled, whereas few of the corticospinal tract neurons were retrogradely labeled. Ependymal cells surrounding the central canal of the spinal cord, which were located far from the injection site, showed a high expression of beta-galactosidase activity. Motoneurons around the injection site were strongly stained by X-gal staining, and their axons in the ventral root were anterogradely labeled. Afferent fibers in the dorsal root were labeled by the transganglionic transport of beta-galactosidase. To examine the efficacy of the uptake and retrograde transport of HRP and adenovirus, we injected a mixed solution of 10% HRP and recombinant adenovirus. The number of HRP-labeled corticospinal neurons overwhelmed the number of X-gal stained ones, while the numbers of HRP-labeled rubrospinal and subcoeruleus-spinal neurons were smaller in comparison with the numbers of beta-galactosidase-positive counterparts. The present study revealed that the origins for the spinal descending tracts except for corticospinal neurons could be efficiently gene-transferred by the retrograde infection of a recombinant adenovirus. Such a difference in efficacy of retrograde infection among the spinal descending tracts is practically important when an adenovirus-mediated gene transfer is designed to treat certain neurological diseases affecting the spinal descending tracts.

Neuronal lineage-specific induction of phospholipase Cepsilon expression in the developing mouse brain.

Phospholipase C is a key enzyme of intracellular signal transduction in the central nervous system. We and others recently discovered a novel class of phospholipase C, phospholipase Cepsilon, which is regulated by Ras and Rap small GTPases. As a first step toward analysis of its function, we have examined the spatial and temporal expression patterns of phospholipase Cepsilon during mouse development by in situ hybridization and immunohistochemistry. Around embryonic day 10.5, abundant expression of phospholipase Cepsilon is observed specifically in the outermost layer of the neural tube. On embryonic day 12 and later, it is observed mainly in the marginal zone of developing brain and spinal cord as well as in other regions undergoing neuronal differentiation, such as the retina and olfactory epithelium. The phospholipase Cepsilon-expressing cells almost invariably express microtubule-associated protein 2, but hardly express nestin or glial fibrillary acidic protein, indicating that the expression of phospholipase Cepsilon is induced specifically in cells committed to the neuronal lineage. The expression of phospholipase Cepsilon persists in the terminally differentiated neurons and exhibits no regional specificity. Further, an in vitro culture system of neuroepithelial stem cells is employed to show that abundant expression of phospholipase Cepsilon occurs in parallel with the loss of nestin expression as well as with the induction of microtubule-associated protein 2 expression and neuronal morphology. Also, glial fibrillary acidic protein-positive glial lineage cells do not exhibit the high phospholipase Cepsilon expression. These results suggest that the induction of phospholipase Cepsilon expression may be a specific event associated with the commitment of the neural precursor cells to the neuronal lineage.