• Journal of Life Science
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• v.30 no.8
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• pp.708-712
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• 2020

Vacuolar protein sorting (VPS) 26b is a newly discovered member of the retromer complex; it is encoded by a single-copy gene located on mouse chromosome 9, and the complex has been reported as being composed of proteins VPS26, VPS29, and VPS35. We have previously shown that mice lacking VPS26b exhibited no significant body size or health issues. Although retromer components are widely expressed in mouse tissue, their roles have not yet been completely elucidated. The current study investigates whether the VPS26b-associated retromer complex can be used as a neurodegeneration model. Previously, we observed a significant reduction in VPS35 and VPS29 in the brain cells of in VPS26b-deficient mice as well as an absence of the VPS26b-VPS29-VPS35 retromer complex despite the normal presence of VPS26a-VPS29-VPS35. Recent studies have suggested that low levels of VPS35 can lead to Alzheimer's disease-like phenotypes including cognitive memory deficits. In this study, we successfully demonstrate an association between the absence of the VPS26b-VPS29-VPS35 retromer complex, reduced cell density in the CA3 region of the hippocampus, and learning disability in VPS26b knock-out mice. The results also indicate that the VPS26b-associated retromer complex affects neurodegenerative disorders and learning processes.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.248-253
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• 2007

This research investigated whether exposure of diesel exhaust particulate (DEP) and particulate matter (PM) effects on airway remodeling in asthma induced Balb/c and IL-10 knock out (KO) mouse. Mice were sensitized with intraperitoneal injection with ovalbumin, followed by challenges with intranasal ovalbumin. After that mice placed in inhalation chamber and exposed to DEP and $PM(10\;mg/m^3)$. The evidence of airway remodeling was assessed by masson's trichrome staining and PAS staining. The stainability of masson's trichrome and PAS reaction were increased in asthma-induced Baltic mice groups compared with control mice groups. More intensive stainability for masson's trichrome and PAS were appeared in the asthma-induced DEP and PM-exposed groups than asthama-induced groups. But, not significantly increased subepithelial fibrosis and the nember of goblet cell hyperplasia in asthma-induced IL-10 KO mice groups and asthma-induced+DEP and PM-exposed IL-10 KO mice than IL-10 KO mice groups. These results indirectly suggesting that exposure to DEP and PM in asthmatic patients might be aggravate clinical symptoms and IL-10 which seems to play a central role in allergic asthma. In conclusion, DEP and PM exposure might have additive effects on the ovalbumin- induced asthma in a murine model.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.295-301
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• 2011

Aquaporin is a water channel protein, which is classified as Major Intrinsic Protein (MIP), found in almost all organisms from bacteria to human. To date, more than 200 members of this family were identified. There are two major categories of MIP channels, orthodox aquaporins and aquaglyceroporins, which facilitate the diffusion across biological membranes of water or glycerol and other uncharged compounds, respectively. The full genome sequencing of various fungal species revealed 3 to 5 aquaporins in their genome. Although some functions of aquaporins found in yeast were characterized, however, no functional characteristics were studied so far in filamentous fungi, including Aspergillus sp. In this study, one orthodox aquaporin homolog gene, aqpA, and four aquaglyceroporin homologs, aqpB-E, in a model filamentous fungus Aspergillus nidulans were identified and the function of the aqpA gene was characterized. Knock-out of the aqpA gene didn't show any obvious phenotypic change under the osmotic stress, indicating that the function of the gene does not involved in the osmotic stress response or the function could be redundant. However, the mutant showed antifungal susceptibility resistance phenotype, suggesting that the function of the aqpA gene could be involved in sensing the antifungal substances rather than the osmotic stress response.

• BMB Reports
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• v.55 no.4
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• pp.198-203
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• 2022

As negative regulators of cytokine signaling pathways, suppressors of cytokine signaling (SOCS) proteins have been reported to possess both pro-tumor and anti-tumor functions. Our recent studies have demonstrated suppressive effects of SOCS1 on epithelial to mesenchymal signaling in colorectal cancer cells in response to fractionated ionizing radiation or oxidative stress. The objective of the present study was to determine the radiosensitizing action of SOCS1 as an anti-tumor mechanism in colorectal cancer cell model. In HCT116 cells exposed to ionizing radiation, SOCS1 over-expression shifted cell cycle arrest from G2/M to G1 and promoted radiation-induced apoptosis in a p53-dependent manner with down-regulation of cyclin B and up-regulation of p21. On the other hand, SOCS1 knock-down resulted in a reduced apoptosis with a decrease in G1 arrest. The regulatory action of SOCS1 on the radiation response was mediated by inhibition of radiation-induced Jak3/STAT3 and Erk activities, thereby blocking G1 to S transition. Radiation-induced early ROS signal was responsible for the activation of Jak3/Erk/STAT3 that led to cell survival response. Our data collectively indicate that SOCS1 can promote radiosensitivity of colorectal cancer cells by counteracting ROS-mediated survival signal, thereby blocking cell cycle progression from G1 to S. The resulting increase in G1 arrest with p53 activation then contributes to the promotion of apoptotic response upon radiation. Thus, induction of SOCS1 expression may increase therapeutic efficacy of radiation in tumors with low SOCS1 levels.

• Journal of Life Science
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• v.16 no.5
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• pp.780-787
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• 2006

Asthma is a chronic inflammatory disorder of the airways, which characterized by bronchial hyperresponsiveness, reversible airflow limitation and respiratory symptoms. Internationally, the prevalence of asthma has been increased over last 3 decades. Recently, several studies of asthma have been reported with gradually increasing importance. To tesify the hypothesis that interleukin (IL)-4 and IL-10 may be an important determinant of the severity of airway inflammation, their expression was studied in mouse model of asthma. BALB/c mouse, IL-4 Knockout (KO) mouse and IL-10 KO mouse were sensitized with intraperitoneal injection of ovalbumin adsorbed to aluminum potassium sulfate, followed by challenges with intranasal ovalbumin on 3 consecutive days. The severity of pulmonary inflammation was assessed by eosinophilia in BAL fluid, number of total BAL cells, histopathological changes in lung tissues, and immunohistochemical staining against IL-4 and IL-10. In BAL fluid, the number of total cells was significantly increased in asthma induced mouse compare to the control. In asthma induced mouse, eosinophil was increased to 56% and neutrophil was 0.2%. In H &E stains, eosinophilic infiltration and epithelium hyperplasia were clearly noticed in asthma induced mouse. In immunohistochemical staining for IL-4 and IL-10, there was no positive reaction in control group. However, very strong reactions were appeared in asthma induced group. In this research, IL-4 and IL-10, which seem to play a central role in allergic asthma, KO mouse was utilized to test the causative relationship between airway inflammation and role of specific cytokine. Asthma induced IL-4 and IL-10 KO mice showed much decreased inflammatory reactions in the number of total BAL cells, in eosinophilic infiltration, and in immunohistochemical stains against diverse inflammatory proteins. These results suggest that IL-4 and IL-10 increase the asthmatic reactions in vivo mice model.

• Development and Reproduction
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• v.13 no.2
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• pp.105-114
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• 2009

Ethane 1,2-dimethane sulfonate (EDS) is a well-known alkylating agent used as selective Leydig cell (LC) toxicant to create a testicular dysfunction model. Previous studies including our own clearly demonstrated the dramatic weight loss of the androgen dependent accessory sex organs such as epididymis, seminal vesicle and prostate gland in this 'LC knock-out' rats. The present study was performed to evaluate the effect of EDS administration on histological changes of the epididymis, seminal vesicle and prostate in adult rats. Adult male Sprague-Dawley rats (350$\sim$400 g B.W.) were injected with a single dose of EDS (75 mg/kg, i.p.) and sacrificed on weeks 0, 1, 2, 3, 4, 5, 6 and 7. Tissue weights (testis, epididymis, seminal vesicle and prostate gland) were measured. The histological changes of tissue were observed by a light microscopy using hematoxylin & eosin staining. Weights of the reproductive and accessory organs progressively declined after the EDS treatments (weeks 1, 2 and 3). After this, the decrease was stopped, then gradually returned to the normal levels. There was a partial (about 60%) recovery of the epididymis weight during weeks $6{\sim}7$. The cross section of epididymis revealed an increase in thickness of the epithelium during weeks $1{\sim}3$. In contrast, considerable reduction of epithelial thickness in seminal vesicle was observed during same period. Similarly, a reduction in thickness of prostate epithelial layer was found during weeks $1{\sim}3$, then it was back to normal thickness after week 4. Taken together, the present study demonstrated that the temporally induced androgen-deficiency by EDS treatment could result the prominent alterations in histology of the accessory sex organs. Further studies on the physiological and molecular regulation of these androgen-sensitive organs using EDS model will be helpful to understand the normal and pathological development and differentiation mechanism of these organs.

• Development and Reproduction
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• v.10 no.3
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• pp.203-209
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• 2006

Ethane 1,2-Dimethane sulfonate(EDS), a toxin which specifically kills Leydig cells(LC), has been widely used to prepare the reversible testosterone(T) depletion rat model. Previous studies including our own clearly demonstrated that the dramatic weight loss of the T-dependent accessory sex organs such as epididymis and seminal vesicle in this 'LC knock-out' rats. These weight loss could be derived from massive and abrupt death of the cells via apoptotic process. The present study was performed to test the effect of EDS administration on the expression of some apoptotic genes in the rat epididymis. Adult male Sprague-Dawley rats($300{\sim}350$ g B.W.) were injected with single dose of EDS(75 mg/kg, i.p.) and sacrificed on Weeks 0, 1, 2, 3, 4, 5, 6 and 7. Tissue weights and the numbers of the epididymal sperm were measured. The transcriptional activities of the bcl-2, bax, Fas and Fas ligand(Fas-L) were evaluated by semi-quantitative RT-PCR. As expected, the weights and the sperm counts of epididymis declined progressively after the EDS treatment during Week 1 and 2. These decrements were discontinued with a gradual return towards normal during Weeks $5{\sim}7$, although the maximal recoveries of the epididymal weights(71%) and sperm count(38%) were subnormal on Week 7. The initial level of bcl-2 transcripts persisted to Week 6 then elevated significantly on Week 7. The level of bax transcripts significantly decreased on Week 6, and no remarkable change was found in the rest of the experimental period. The transcripts for the Fas in epididymis elevated during Weeks $1{\sim}2$, returned to normal on Week 3, and the level persisted to the Week 7. Similarly, the level of Fas-L transcripts elevated during Weeks $1{\sim}3$ and returned to normal after Week 4. Our results demonstrated the transient T depletion by EDS administration could induce the changes in expression of the apoptotic genes in rat epididymis. The activation of Fas and Fas-L in the epididymis of EDS-treated rats might be responsible for the initial apototic process and consequently the tissue damage and the sperm loss. Future studies will attempt to determine the precise molecular mechanism(s) of apoptosis in the rat epididymis.

• Journal of Life Science
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• v.32 no.1
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• pp.11-22
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• 2022

N-methyl-D-aspartate (NMDA) receptors have received considerable attention regarding their involvement in glutamate-induced neuronal excitotoxicity. Resveratrol has been shown to exhibit neuroprotective effects against this kind of overactivation, but the underlying cellular mechanisms are not yet clearly understood. In this study, HT-22 neuronal cells were treated with NMDA in Mg²⁺-free buffer and subsequently used as an experimental model of glutamate excitotoxicity to elucidate the mechanisms of resveratrol-induced neuroprotection. We found that NMDA treatment causes a drop in MTT reduction ability, disrupts inside-negative transmembrane potential of mitochondria, depletes cellular ATP levels, and stimulates intracellular ROS production. Double fluorescence imaging studies demonstrated an increased formation of mitochondrial permeability transition (MPT) pores accompanied by apoptotic cell death, while cobalt protoporphyrin and bilirubin showed protective effects against NMDA-induced mitochondrial injury. On the other hand, zinc protoporphyrin IX significantly attenuated the protective effects of resveratrol which was itself shown to enhance heme oxygenase-1 (HO-1) mRNA and protein expression levels. In cells transfected with HO-1 small interfering RNA, resveratrol failed to suppress the NMDA-induced effects on MTT reduction ability and MPT pore formation. The present study suggests that resveratrol may prevent mitochondrial injury in NMDA- treated HT-22 cells and that enhanced expression of HO-1 is involved in the underlying cellular mechanism.