Gye-Yeop Kim

Detection and molecular characterization of porcine group C rotaviruses in South Korea.

Abstract Group C rotaviruses (GCRVs) cause acute diarrhea in humans and animals worldwide and the evidence for a possible zoonotic role of GCRVs has been recently provided. However, there is little evidence of porcine GCRV infections or of their genetic diversity in South Korea. We examined 137 diarrheic fecal specimens from 55 farms collected from six provinces. RT-PCR utilizing primer pairs specific for the GCRV VP6 gene detected GCRV-positive reactions in 36 (26.2%) diarrheic fecal samples. Of these, 17 samples (12.4%) tested positive for porcine GCRVs alone and 19 samples (13.8%) were also positive for other pathogens. Other enteric pathogens except for GCRV were detected in 64 feces samples (46.7%) and no enteric pathogens were evident in 37 feces samples (27.0%). Phylogenetic and sequence homology analyses of GCRV partial VP6 gene between 23 Korean and other known porcine GCRVs demonstrated that Korean strains belonged to the porcine lineage. Furthermore, one Korean porcine strain shared the highest nucleotide (89.7–89.0%) and deduced amino acid sequence (92.9–93.9%) identities with bovine GCRV strains and was placed in the bovine GCRV lineage indicative of bovine origin. In conclusion, porcine GCRV infections are widespread in piglets with diarrhea in South Korea. The infecting porcine GCRVs mostly belong to the porcine lineage with the exception of one bovine-like GCRV, which possibly originated from bovine GCRV due to interspecies transmission.

Dual enteric and respiratory tropisms of winter dysentery bovine coronavirus in calves

SummaryAlthough winter dysentery (WD), which is caused by the bovine coronavirus (BCoV) is characterized by the sudden onset of diarrhea in many adult cattle in a herd, the pathogenesis of the WD-BCoV is not completely understood. In this study, colostrum-deprived calves were experimentally infected with a Korean WD-BCoV strain and examined for viremia, enteric and nasal virus shedding as well as for viral antigen expression and virus-associated lesions in the small and large intestines and the upper and lower respiratory tract from 1 to 8 days after an oral infection. The WD-BCoV-inoculated calves showed gradual villous atrophy in the small intestine and a gradual increase in the crypt depth of the large intestine. The WD-BCoV-infected animals showed epithelial damage in nasal turbinates, trachea and lungs, and interstitial pneumonia. The WD-BCoV antigen was detected in the epithelium of the small and large intestines, nasal turbinates, trachea and lungs. WD-BCoV RNA was detected in the serum from post-inoculation day 3. These results show that the WD-BCoV has dual tropism and induces pathological changes in both the digestive and respiratory tracts of calves. To our knowledge, this is the first detailed report of dual enteric and respiratory tropisms of WD-BCoV in calves. Comprehensive studies of the dual tissue pathogenesis of the BCoV might contribute to an increased understanding of similar pneumoenteric CoV infections in humans.

Molecular analysis of S gene of spike glycoprotein of winter dysentery bovine coronavirus circulated in Korea during 2002-2003.

Abstract Since the molecular analysis of spike (S) glycoprotein gene of bovine coronavirus (BCoV) has been conducted and compared mainly among American and Canadian isolates and/or strains, it is unclear whether BCoV circulated in the other countries are distinctive in genetic characteristics. In the present study, we analyzed the S glycoprotein gene to characterize 10 winter dysentery (WD) coronavirus strains circulated in Korea during 2002–2003 and compared the nucleotide (nt) and deduced amino acid (aa) sequences with the other known BCoV. The phylogenetic analysis of the entire S glycoprotein gene revealed that the aa sequences of all Korean WD strains were more homologous to each other and were very closely related to respiratory bovine coronavirus (RBCV) strain OK and enteric bovine coronavirus (EBCV) strain LY-138, but were distinct from the other known BCoVs. Based on the phylogenetic analysis of the hypervariable region of the S1 subunit, all Korean WD strains clustered with the respiratory strain OK, BCQ3994 and the enteric strain LY-138, while the Canadian BCQ calf diarrhea and WD strains, and the American RBCV LSU, French EBCV F15 and avirulent VACC, L9, and Mebus strains clustered on a separate major branch. These data suggest that the WD strains circulated in Korea had a genetic property of both RBCV and EBCV and were significantly distinct from the ancestral enteric strain.

Hyperglycemia induces apoptosis via CB1 activation through the decrease of FAAH 1 in retianl pigment epithelial cells

Fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of the main endocannabinoid, anandamide, and related fatty acid amides, has emerged as a regulator of endocannabinoid signaling. Retinal pigment epithelial (RPE) cells are believed to be important cells in the pathogenesis of diabetic retinopathy. However, the pathophysiology of FAAH in diabetic retinopathy has not been determined. Thus, we examined the effect of high glucose (HG) on the expression of FAAH and CB1R in the ARPE‐19 human RPE cells. We found that HG downregulated the expression of FAAH 1 mRNA and protein in ARPE‐19 cells. In contrast, it upregulated the expression of CB1R mRNA and protein. HG‐induced internalization of CB1R in HEK 293 cells and ARPE‐19 cells was blocked by overexpression of FAAH 1 and treatment with the CB1R blocker, AM 251. HG‐induced generation of reactive oxygen species and lipid peroxide formation were blocked by the overexpression of FAAH 1. FAAH 1 overexpression also blocked HG‐induced expression of CB1R in the cytosolic fraction. We also investigated whether the overexpression of FAAH 1 protected against HG‐induced apoptosis. High glucose increased the Bax/Bcl‐2 ratio and levels of cleaved PARP, cleaved caspase‐9 and caspase‐3, and reduced cell viability. HG‐induced apoptotic effects were reduced by the overexpression of FAAH 1, treatment with the CB1R‐specific antagonist AM 251 and CB1R siRNA transfection. In conclusion, HG‐induced apoptosis in ARPE‐19 cells by inducing CB1R expression through the downregulation of FAAH 1 expression. Our results provide evidence that CB1R blockade through the recovery of FAAH 1 expression may be a potential anti‐diabetic therapy for the treatment of diabetic retinopathy. J. Cell. Physiol. 227: 569–577, 2012.

The Effects of Antecedent Exercise on Motor Function Recovery and Brain-derived Neurotrophic Factor Expression after Focal Cerebral Ischemia in Rats.

[Purpose] In the present study, we investigated the effect of antecedent exercise on functional recovery and brain-derived neurotrophic factor (BDNF) expression following focal cerebral ischemia injury. [Subjects] The rat middle cerebral artery occlusion (MCAO) model was employed. Adult male Sprague-Dawley rats were randomly divided into 4 groups. Group I included untreated normal rats (n=10); Group II included untreated rats with focal cerebral ischemia (n=10); Group III included rats that performed treadmill exercise (20 m/min) training after focal cerebral ischemia (n=10); and Group IV included rats that performed antecedent treadmill exercise (20 m/min) training before focal cerebral ischemia (n=10) as well as treadmill exercise after ischemia. At different time points (1, 7, 14, and 21 days) Garcia’s score, and the hippocampal expressions level of BDNF were examined. [Results] In the antecedent exercise group, improvements in the motor behavior index (Garcia’s score) were observed and hippocampal BDNF protein expression levels increased. [Conclusion] These results indicate that antecedent treadmill exercise, before permanent brain ischemia exerts a neuroprotective effect against ischemia brain injury by improving motor performance and increasing the level of BDNF expression. Furthermore, the antecedent treadmill exercise of appropriate intensity is critical for post-stroke rehabilitation.

Effects of treadmill training on limb motor function and acetylcholinesterase activity in rats with stroke.

[Purpose] In the present study, we investigated the effects of treadmill training on limb motor function and acetylcholinesterase activity following focal cerebral ischemia injury. [Methods] Focal cerebral ischemia was examined in adult male Sprague-Dawley rats by using a middle cerebral artery occlusion model. Rats were randomly divided into 3 groups. Group I included untreated normal rats (n=12), Group II included untreated rats with focal cerebral ischemia (n=12), and Group III included rats that performed treadmill exercise (20 m/min) training after focal cerebral ischemia (n=12). We determined the limb placement test score for each rat on days 1,7, 14, and 21; acetylcholinesterase activity in the hippocampus was examined at the end of the experiment. [Results] We observed that the motor behavior index improved in the treadmill group, and hippocampal acetylcholinesterase activity was decreased. [Conclusion] These results indicated that treadmill training after focal cerebral ischemia exerts a neuroprotective effects against ischemic brain injury by improving motor performance and decreasing the levels of acetylcholinesterase activity. Furthermore, these results suggest that treadmill training at an appropriate intensity is critical for post-stroke rehabilitation.

Changes in Salmon (Oncorhynchus keta) Flesh Quality Following Ultra-High Pressure Treatment and 30 d of Chilled Storage

The approximately 1.5 million tons of salmon traded in 31 countries in 2008 provides clear evidence that salmon is a popular food source throughout the world. There are many methods for the preservation of salmon flesh, such as vacuum-packaging, smoking, and freezing. Ultra-high pressure (UHP) does not require heat, preserves the quality of salmon flesh, and allows for an increase in the chilled storage period. In this study, the quality of salmon flesh was assessed after exposure to UHP (200, 400, or 600 MPa compared with no UHP) and 30 d of storage at 4 °C. Salmon flesh quality analyses included the degree of changes in the interspacing of muscle bundles, color, texture profiles (hardness, chewiness, cohesiveness, and elasticity), and microbial growth. The use of UHP (>400 MPa) improved the color, hardness, and chewiness of the flesh. Study results suggested that the application of UHP (≥400 MPa) may be useful in preserving salmon flesh, and could be used by the salmon aquaculture and distribution industries.

Molecular characterization of HE, M, and E genes of winter dysentery bovine coronavirus circulated in Korea during 2002-2003.

The different bovine coronavirus (BCoV) strains or isolates exhibited various degrees of substitutions, resulting in altered antigenicity and pathogenicity of the virus. In the previous our study, we demonstrated that the spike glycoprotein gene of Korean winter dysentery (WD) BCoV had a genetic property of both enteric (EBCV) and respiratory BCoV (RBCV) and were significantly distinct from the ancestral enteric strains. In the present study, therefore, we analyzed the other structure genes, the hemagglutinin/esterase (HE) protein, the transmembrane (M) protein and the small membrane (E) protein to characterize 10 WD BCoV circulated in Korea during 2002–2003 and compared the nucleotide and deduced amino acid sequences with the other known BCoV. Phylogenetic analysis indicated that the HE gene among BCoV could be divided into three groups. The first group included only RBCV, while the second group contained calf diarrhea BCoV, RBCV, WD and EBCV, respectively. The third group possessed only all Korean WD strains which were more homologous to each other and were sharply distinct from the other known BCoV, suggesting Korean WD strains had evolutionary distinct pathway. In contrast, the relative conservation of the M and E proteins of BCoV including Korean WD strains and the other coronaviruses suggested that structural constraints on these proteins are rigid, resulting in more limited evolution of these proteins. In addition, BCoV and human coronavirus HCV-OC43 contained four potential O-glycosylation sites in the M gene. However, the M gene sequence of both BCoV and HCV-OC43 might not contain a signal peptide, suggesting the M protein might be unlikely to be exposed to the O-glycosylation machinery in vivo.

Asymmetric dimethylarginine (ADMA) treatment induces apoptosis in cultured rat mesangial cells via endoplasmic reticulum stress activation

Asymmetric dimethylarginine (ADMA), a high risk factor for endothelial dysfunction and cardiovascular disease (CVD), has been reported to promote cellular dysfunction via endoplasmic reticulum (ER) stress activation in various cells. Additionally, increased serum ADMA levels have been observed in incipient kidney diseases. Previously, we reported that activated ER stress is associated with mesangial cell apoptosis, observed mainly in overt nephropathy or chronic kidney disease (CKD). However, the effect of ADMA on mesangial cell apoptosis is unknown. Thus, we investigated the effects of ADMA on mesangial cell apoptosis and ER stress signaling. ADMA treatment increased caspase‐3 activity and activated three branches of ER stress signaling (PERK, IRE1, and ATF6) that induce mesangial cell apoptosis. Pharmacological inhibitors of ER stress (inhibitors of PERK, IRE1, and S1P) attenuated ADMA‐induced cleavage of caspase‐3 and induced a decrease in the mitochondrial membrane potential. Furthermore, these inhibitors diminished the number of apoptotic cells induced by ADMA treatment. Taken together, our results indicated that ADMA treatment induces mesangial cell apoptosis via ER stress signaling. These results suggest that ADMA‐induced mesangial cell apoptosis could contribute to the progression of overt nephropathy and CKD.

Effect of Lithospermi Radix on Contact Dermatitis Induced by Dinitrofluorobenzene in Mice

Objective: The root of Lithospermum erythrorhizon Sieb. et Zucc. (Lithospermi Radix, LR) is a kind of heat clearing and blood cooling medicinal herbs. It can clear away heat and cool the blood, reduce toxins and disperse maculae. LR has long been used as efficacious therapy for inflammation, burns, frostbite and skin diseases such as eczema and psoriasis. Methods: In the present study, we investigate anti-allergic and anti-inflammatory effects of LR by using the 1-fluoro-2, 4- dinitrofluorobenzene (DNFB)-induced contact dermatitis mouse model. Results: Topical application of 10 mg/mL of LR effectively inhibited skin lesions induced by repeated paintings with DNFB. Topical application of LR also inhibited hyperplasia, edema, spongiosis and infiltrations of mononuclear cells. In addition, production levels of total immunoglobulin and IgG1 in serum were decreased by using LR in vivo. Conclusion: These data suggest that LR acts as an antiinflammatory agent, improving skin lesions in CD mice.