Bcl-2 Interacting Death Suppressor Research Articles

Expression of Bis in the mouse gastrointestinal system

The Bcl-2 interacting death suppressor (Bis) protein is known to be involved in a variety of pathophysiological conditions. We recently generated bis-deficient mice, which exhibited early lethality with typical nutritional deprivation status. To further investigate the molecular basis for the malnutrition phenotype of bis deficient mice, we explored Bis expression in the digestive system of normal mice. Western blot analysis and quantitative real time reverse transcription polymerase chain reaction analysis indicated that Bis expression is highest in the esophagus, followed by the stomach, colon, jejunum and ileum. Immunohistochemical data indicated that Bis expression is restricted to the stratified squamous epitheliums in the esophagus and forestomach, and was not notable in the columnar epitheliums in the stomach, small intestine and colon. In addition, strong Bis immunoreactivity was detected in the striated muscles surrounding the esophagus and smooth muscles at a lesser intensity throughout the gastrointestinal (GI) tract. Ganglionated plexuses, located in submucous layers, as well as intermuscular layers, were specifically immunoreactive for Bis. Immunofluorescence studies revealed that Bis is co-localized in glial fibrillary acidic protein-expressing enteric glial cells. Immunostaining with neuron specific esterase antibodies indicate that Bis is also present in the cell bodies of ganglions in the enteric nervous system (ENS). Our findings indicate that Bis plays a role in regulating GI functions, such as motility and absorption, through modulating signal transmission between the ENS and smooth muscles or the intestinal epitheliums.

Transient expression of Bis protein in midline radial glia in developing rat brainstem and spinal cord

Bis (Bcl-2 interacting death suppressor) has been reported to contribute to the differentiation and maturation of specific neuronal populations in the developing rat forebrain, in addition to its well-established functions as a stress or survival-related protein. In the present study, we have analyzed the expression of Bis in the rat brainstem and cervical spinal cord during development by using immunohistochemistry. Bis immunoreactivity was detected in radial glial cells flanking the midline from embryonic day 14. During embryonic and early postnatal development, Bis expression persisted in differentiating radial glia at the midline but disappeared first in the spinal cord by postnatal day 7 (P7) and later also in the brainstem by P14. Bis expression was restricted to a subpopulation of the midline radial glia, i.e., the dorsal midline of the midbrain and spinal cord and the ventral midline of the hindbrain, which were double- or triple-labeled with vimentin and nestin, markers for radial glia, and S100B. However, these markers also labeled all radial glia including the ventral midline glia in the midbrain and spinal cord, with Bis being absent from these structures. In addition, the dorsal midline glia in the midbrain and spinal cord expressed Bis prior to the timing of expression for radial glial markers. Therefore, our results demonstrate the early and transient expression of Bis in the subpopulation of midline glia in the developing brainstem and spinal cord, suggesting that Bis has a unique role in association with the radial glial cells in the developing central nervous system.

Developmental expression of Bis protein in the cerebral cortex and hippocampus of rats

Bis (Bcl-2 interacting death suppressor), identified as a Bcl-2-binding protein, has been suggested to have diverse functions in addition to binding to Bcl-2, thereby regulating cell death. To investigate the potential role of Bis in the developing brain, the spatiotemporal expression of Bis protein was studied in the rat forebrain during prenatal and early postnatal development using immunohistochemistry. Initial expression of Bis was detected in the medial telencephalic wall of the lateral ventricle, the area most likely corresponded to the cortical hem from the earliest age examined (E13). There was an abrupt increase of immunoreactive neurons in the cortex and hippocampus during the first postnatal week, which declined thereafter. Two populations of Bis-immunoreactive neurons can be clearly distinguished in the developing forebrain: a population of differentiating and postmitotic neurons coexpressing Bis and microtubule-associated protein-2 (MAP-2), and a population of neurons with the characteristic morphology of Cajal-Retzius cells located exclusively in the marginal zone/layer I of the cortex and in the hippocampal equivalents of the marginal zone. The latter neurons were colabeled with reelin, a marker for Cajal-Retzius cells. While Bis expression in the cerebral cortex and hippocampus exists only transiently by P14, considerable expression was found to be maintained in the rostral migratory stream and the subventricular zone of the lateral ventricle, where Bis-immunoreactive cells were glutamine synthetase-positive glial cells. Our results suggest that Bis may contribute to the developmental processes, including the differentiation and maturation of specific neuronal populations in relation to Bcl-2 in the developing rat forebrain.

Immunohistochemical localization of Bis protein in the rat central nervous system.

We studied the distribution of Bis (Bcl-2 interacting death suppressor) protein in the adult rat brain and spinal cord using immunohistochemistry. Immunoreactivity was observed in specific neuronal populations in distinct nuclei. The most intensely labeled cells were associated with the motor system, including most cranial nerve motor nuclei, Purkinje cells of the cerebellum, the red nucleus, and the ventral motor neurons of the spinal cord. Bis protein was also expressed in several structures associated with the ventricular system, including the subventricular zone of the lateral ventricle and its rostral extension, in the subcommissural organ, and in tanycytes, radial glial cells in the hypothalamus. Using double-labeling techniques, Bis-immunoreactive cells in the rostral migratory stream, coexpressing Bcl-2, were confirmed as glial fibrillary acidic protein-positive astrocytes comprising the glial tubes. The widespread distribution of Bis suggests that this protein has broader functions in the adult rat central nervous system than previously thought, and that it could be associated with a particular role in the rostral migratory system.

Identification of differentially expressed genes induced by transient ischemic stroke

We have used a rat model of focal cerebral ischemia to investigate changes in gene expression that occur during stroke. To monitor these changes, we employed representational difference analysis–polymerase chain reaction (PCR). A total of 128 unique gene fragments were isolated, and we selected 13 of these for quantitative reverse transcriptase-PCR analysis. Of these 13 genes, we found seven that were differentially expressed. Four of these genes have not previously been implicated in stroke, and include neuronal activity regulated pentraxin (Narp), cystein rich protein 61 (Cyr61), Bcl-2 binding protein BIS (Bcl-2-interacting death suppressor), and lectin-like ox-LDL receptor (LOX-1). We demonstrated differential expression of each gene by quantitative PCR analysis, and in the case of LOX-1, we further confirmed differential expression by in situ hybridization. LOX-1 expression is induced greater than ten fold at the core lesion site, and is essentially localized to the ipsilateral half of the brain. LOX-1 appears to be expressed in a non-neuronal cell type, and it does not appear to be expressed in vascular endothelial cells within the brain. This suggests that LOX-1 may serve a novel function in the brain.