Biomedical subjects

Sa Sun Cho

Publications and source records attributed to Sa Sun Cho.

8 recordsLinked to original sources

PubMed2003

Heat shock protein 108 mRNA expression during chicken retina development.

In a developmental study on the expression of heat shock protein 108 (HSP108) mRNA in the chicken retina, we found different spatial and temporal expressions of HSP108 mRNA in each retinal layer. While intense HSP108 signals were found in the retina neuroblast layer at embryonic day 5 (E5), the ganglion cell population (GC), inner nuclear layer (IN) and pigment epithelium (PE) showed HSP108 expression at E9. At E14, HSP108 signals were reduced versus the previous stages even though signals were still detected in the GC, the IN, the outer nuclear layer and the PE. HSP108 signals were still detectable at the E21 stage, although each retinal layer showed a much differentiated morphology and diminished signal intensity. These results suggest that HSP108 expression might be developmentally regulated throughout eye organogenesis and that it plays a role in ocular development.

Animals↗

PubMed2003

The correspondence between the labeling patterns of antibody RT97, neurofilaments, microtubule associated protein 1B and tau varies with cell types and development stages of chicken retina.

The correspondence between the labeling patterns of antibody RT97, neurofilaments (NF-M and NF-H), microtubule associated protein 1B (MAP1B) and tau, were studied in the developing chicken. At embryonic day 3 (E3), intense RT97 immunoreactivity (IR) was found to be localized in cells in the region adjacent to the intraretinal space, which separates the inner and outer layers of the optic cup, and this was sustained at E8. However, this pattern changed dramatically at E12, as the intensities of RT97 IR increased in the inner retinal layer, while the outermost layers showed only weak IR. The adult stage retina showed RT97 IR within the nerve fibers of the ganglion cells, the processes of the amacrine cells and the photoreceptors. Additional immunostainings for NF-M, -H, MAP1B and tau showed that the observed changes in RT97 IRs were due to the different expressions of these proteins at different development stages.

Animals↗

PubMed2003

Caveolin-3 expression during early chicken development.

Caveolin-3, a protein that is correlated with caveolae, is found in muscle cells, especially during their differentiation. Although the distribution of caveolin-3 has been studied in cases such as adult and late embryonic mammalians, the expression of caveolin-3 has not been clearly defined during chicken development. In this study, we detected intense caveolin-3 immunoreactivity (IR) as early as embryonic day 4 (E4), most of the signals were localized within the neural tube and myotome. While IRs in the brain occurred in radial glia at E6, these intensities were reduced to an almost undetectable level at E8. In the case of muscle cells, the exclusive localization of caveolin-3 in the cytoplasmic membrane was detected even at E11, much earlier than in mammalian muscle tissues. Although the caveolin-3 IR pattern was similar to that reported by previous studies, we found some interesting mismatches in the case of avian tissues. Although we are unable to explain caveolin-3 expression patterns in the early embryonic stages, this study could provide a basis for further study on the function of caveolin-3 in avian embryogenesis.

Animals↗

PubMed2003

Glial cells in the chicken optic tectum.

We mapped the distribution of the three neuroglial cells, oligodendrocytes, astrocytes and microglia, in the chicken optic tectum using their specific markers, transferrin binding protein (TfBP), glial fibrillary acidic protein (GFAP), and Ricinus communis agglutinin-1 (RCA-1), respectively. Neuroglial cells showed distinct distribution according to their cell types. While the astrocytes were mainly found in the stratum opticum (SO), stratum album centrale (SAC) and stratum fibrosum periventriculare (SFP), with their processes extending throughout the entire optic tectum region, the oligodendrocytes were mainly scattered in the SO, stratum griseum centrale (SGC) and SAC. In the case of the microglia, ramified cells were found in nearly all the layers, with the majority being present in the SAC. This is the first report demonstrating the distribution of glial cells in the chicken optic tectum, and these findings may present a basis for further study.

Animals↗

PubMed2002

Increased expression of phosphatase and tensin homolog in reactive astrogliosis following intracerebroventricular kainic acid injection in mouse hippocampus.

A phosphatase and tensin homolog (PTEN) has been known to play multiple biological roles. However, role of PTEN in astrocyte activation is not clear yet. In the present study, the expression pattern of PTEN in the process of reactive gliosis was immunohistochemically examined in intracerebroventricular (i.c.v.) injected kainic acid mouse hippocampus. Mice were grouped into three; 30 min, 1 day and 7 days after kainic acid i.c.v. injection. Thirty minutes after kainic acid i.c.v. injection, astrocytes were activated and PTEN was weakly expressed in immature astrocytes. Seven days after kainic acid i.c.v. injection, PTEN expression was decreased in highly activated astrocytes showing extensively spindled shape. Immunofluorescence double labeling experiment showed that PTEN was expressed in glial fibrillary acidic protein-positive astrocytes. These findings suggest that PTEN might have a role in early stage of reactive astrogliosis in vivo.

Animals↗

PubMed2002

Oxidative DNA damage and alteration of glutamate transporter expressions in the hippocampal Ca1 area immediately after ischemic insult.

Although oxidative stress and excitotoxicity may be interdependent mechanisms that are involved in delayed neuronal death, the temporal participation of these events in the early stage after ischemia-reperfusion insult is unclear. Therefore, in the present study, using the gerbil global ischemic model we investigated whether oxidative stress could be correlated with the expression of the glutamate transporters in the hippocampus, and whether these events are related and cooperate in the events that link ischemia to neuronal death in vivo. Thirty minutes after ischemia, the intensities of glutamate transporter-1 (GLT-1), glutamate/aspar-tate transporter (GLAST), and 8-hydroxy2'-deoxy-guanosine (8-OHdG) immunoreactivities were markedly increased in the hippocampal CA1 area. In contrast, excitatory amino acid carrier-1 (EAAC-1) immunoreactivity was 30% lower in the CA1 area than in the sham level. At 3 h post-reperfusion, the EAAC-1 expression began to increase in the CA1 area. Twelve hours after reperfusion, the reduction of both GLT-1 and GLAST immunoreactivity was salient, while the EAAC-1 immunoreactivity level intensified significantly. The 8-OHdG immunoreactivity peaked at this time point. These findings suggest that oxidative stress and alterations in the glutamate transporter expression in the CA1 area may simultaneously trigger neuronal damages very early after ischemia.

Amino Acid Transport System X-AG↗

PubMed2002

Fas ligand mRNA expression in the mouse central nervous system.

Fas ligand (FasL) expressing cells delete Fas bearing T cells, thereby enabling privileged immune status in the brain. Although the presence of FasL immunoreactivity has been shown in various cell types in the central nervous system, the precise in vivo distribution of FasL mRNA in mammals is not known. Accordingly, we localized intense FasL mRNA signals in neuroglial cells mainly within the white matter regions. Using a combined labeling technique of immunocytochemistry and in situ hybridization, we confirmed that FasL signals were due to neuroglial cells rather than neurons. This study shows that FasL mRNA is constitutively expressed in the normal mouse brain, and suggests that the Fas/FasL system protects the CNS from immunological damage.

Animals↗

PubMed2002

Anatomical and neuropeptidergic properties of the duodenal neurons projecting to the gallbladder in the golden hamster.

This study investigated the anatomical and neuropeptidergic properties of the duodenal neurons projecting to the gallbladder in the golden hamster. Fast blue (FB) was injected into the subserosa of the gallbladder in order to identify by retrograde tracing the duodenal neurons that project to the gallbladder. Subsequently, immunofluorescence microscopy was employed to see whether these duodenal neurons contained putative peptidergic neurotransmitters such as calcitonin gene-related peptide (CGRP), galanin (GAL) and vasoactive intestinal polypeptide (VIP). The FB-labeled cells were only found in the duodenal region adjacent to the major duodenal papilla where the biliary duct opens. On the other hand, there was no difference within this duodenal region in the numbers of FB-labeled cells between the mesenteric and antimesenteric portions, suggesting that these two portions of the duodenum equally contribute neuronal projections to the gallbladder. Double-immunofluorescence microscopy clearly demonstrated that a small population of FB-positive duodenal neurons contained putative neurotransmitters CGRP, GAL and VIP. Our data suggest that duodenal neurons around the major duodenal papilla in the golden hamster project to the gallbladder and exert their influence on the gallbladder via neuropeptides such as CGRP, GAL and VIP.

Animals↗