1.Negative feedback regulation of Wnt signaling by Gbetagamma-mediated reduction of Dishevelled.
Hwajin JUNG ; Hyun Joon KIM ; Suk Kyung LEE ; Rokki KIM ; Will KOPACHIK ; Jin Kwan HAN ; Eek hoon JHO
Experimental & Molecular Medicine 2009;41(10):695-706
Wnt signaling is known to be important for diverse embryonic and post-natal cellular events and be regulated by the proteins Dishevelled and Axin. Although Dishevelled is activated by Wnt and involved in signal transduction, it is not clear how Dishevelled-mediated signaling is turned off. We report that guanine nucleotide binding protein beta 2 (Gnb2; Gbeta2) bound to Axin and Gbeta2 inhibited Wnt mediated reporter activity. The inhibition involved reduction of the level of Dishevelled, and the Gbeta2gamma2 mediated reduction of Dishevelled was countered by increased expression of Axin. Consistent with these effects in HEK293T cells, injection of Gbeta2gamma2 into Xenopus embryos inhibited the formation of secondary axes induced either by XWnt8 or Dishevelled, but not by beta-catenin. The DEP domain of Dishevelled is necessary for both interaction with Gbeta2gamma2 and subsequent degradation of Dishevelled via the lysosomal pathway. Signaling induced by Gbeta2gamma2 is required because a mutant of Gbeta2, Gbeta2 (W332A) with lower signaling activity, had reduced ability to downregulate the level of Dishevelled. Activation of Wnt signaling by either of two methods, increased Frizzled signaling or transient transfection of Wnt, also led to increased degradation of Dishevelled and the induced Dishevelled loss is dependent on Gbeta1 and Gbeta2. Other studies with agents that interfere with PLC action and calcium signaling suggested that loss of Dishevelled is mediated through the following pathway: Wnt/Frizzled-->Gbetagamma-->PLC-->Ca+2/PKC signaling. Together the evidence suggests a novel negative feedback mechanism in which Gbeta2gamma2 inhibits Wnt signaling by degradation of Dishevelled.
Adaptor Proteins, Signal Transducing/genetics/*metabolism
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Animals
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Blastomeres/cytology/*metabolism
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Cell Line
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Embryonic Development/genetics
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*Feedback, Physiological
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Frizzled Receptors/genetics/metabolism
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GTP-Binding Proteins/genetics/*metabolism
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Gene Expression Regulation, Developmental
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Humans
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Mutation
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Phosphoproteins/genetics/*metabolism
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Protein Binding
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RNA, Small Interfering/genetics
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Repressor Proteins/genetics/metabolism
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Transfection
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Wnt Proteins/*genetics/metabolism
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Xenopus
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Xenopus Proteins/*genetics/metabolism
2.Epidemiological characteristics of a COVID-19 outbreak caused by religious activities in Daegu, Korea
Jong-Yeon KIM ; Yu-Mi LEE ; Hwajin LEE ; Jung-Whan KIM ; Shin-Woo KIM
Epidemiology and Health 2021;43(1):e2021024-
OBJECTIVES:
A coronavirus disease 2019 (COVID-19) outbreak triggered by religious activities occurred in Daegu, Korea in February 2020. This outbreak spread rapidly to the community through high-risk groups. This study describes the characteristics of COVID-19 cases based on S religious group membership and summarizes the Daegu municipal government’s processes and responses to control the outbreak.
METHODS:
The epidemiological characteristics of confirmed cases were obtained through basic and in-depth epidemiological surveys. General characteristics, the proportion of asymptomatic cases, the case-fatality rate, and the time-to-event within each group were presented after stratifying confirmed cases according to S religious group membership.
RESULTS:
Overall, 7,008 COVID-19 cases were confirmed in Daegu from February 18, 2020 to June 30, 2020, and 61.5% (n= 4,309) were S religious group members. Compared with non-members, members had a higher proportion of female (p< 0.001) and younger age (p< 0.001), as well as lower disease prevalence. At the time of the investigation, 38.4% of cases in members were asymptomatic versus 23.7% of cases in non-members (p< 0.001). The case-fatality rate of non-members aged ≥ 60 years was significantly higher than that of members (p< 0.001). Compared with non-members, members had longer intervals from symptom onset to diagnosis (p< 0.001) and from diagnosis to admission (p< 0.001), and a shorter interval from admission to discharge (p< 0.001).
CONCLUSIONS
The epidemiological features of S religious group members, including the proportion of asymptomatic cases, case-fatality rate, and time-to-event, differed from non-members. The Daegu authorities prevented further COVID-19 spread through immediate isolation and active screening tests of all S religious group members.
3.Epidemiological characteristics of a COVID-19 outbreak caused by religious activities in Daegu, Korea
Jong-Yeon KIM ; Yu-Mi LEE ; Hwajin LEE ; Jung-Whan KIM ; Shin-Woo KIM
Epidemiology and Health 2021;43(1):e2021024-
OBJECTIVES:
A coronavirus disease 2019 (COVID-19) outbreak triggered by religious activities occurred in Daegu, Korea in February 2020. This outbreak spread rapidly to the community through high-risk groups. This study describes the characteristics of COVID-19 cases based on S religious group membership and summarizes the Daegu municipal government’s processes and responses to control the outbreak.
METHODS:
The epidemiological characteristics of confirmed cases were obtained through basic and in-depth epidemiological surveys. General characteristics, the proportion of asymptomatic cases, the case-fatality rate, and the time-to-event within each group were presented after stratifying confirmed cases according to S religious group membership.
RESULTS:
Overall, 7,008 COVID-19 cases were confirmed in Daegu from February 18, 2020 to June 30, 2020, and 61.5% (n= 4,309) were S religious group members. Compared with non-members, members had a higher proportion of female (p< 0.001) and younger age (p< 0.001), as well as lower disease prevalence. At the time of the investigation, 38.4% of cases in members were asymptomatic versus 23.7% of cases in non-members (p< 0.001). The case-fatality rate of non-members aged ≥ 60 years was significantly higher than that of members (p< 0.001). Compared with non-members, members had longer intervals from symptom onset to diagnosis (p< 0.001) and from diagnosis to admission (p< 0.001), and a shorter interval from admission to discharge (p< 0.001).
CONCLUSIONS
The epidemiological features of S religious group members, including the proportion of asymptomatic cases, case-fatality rate, and time-to-event, differed from non-members. The Daegu authorities prevented further COVID-19 spread through immediate isolation and active screening tests of all S religious group members.
4.Venous Sinus Thrombosis and Dural Arteriovenous Fistula after Herpes Simplex Encephalitis in a Patient with Protein S, Protein C Deficiency
Yujin SONG ; Hwajin CHOI ; Yunyoung CHOI ; Hyunkyum CHO ; Dongyu KIM ; Yo Han JUNG
Journal of the Korean Neurological Association 2024;42(2):162-165
Herpes simplex encephalitis is known to cause intracranial hypertension and cerebral edema. When cerebral edema occurs, venous sinuses are compressed, resulting in congestion and thrombosis. An arteriovenous fistula may form as a result, particularly in conjunction with superior sagittal sinus thrombosis. In this report, the authors describe a patient with protein S and C deficiency who developed venous sinus thrombosis and dural arteriovenous fistula after experiencing herpes simplex encephalitis.
5.Ultrasonographic features of pure ductal carcinoma in situ of the breast: correlations with pathologic features and biological markers.
Hwajin CHA ; Yun Woo CHANG ; Eun Ji LEE ; Ji Young HWANG ; Hyun Joo KIM ; Eun Hye LEE ; Jung Kyu RYU
Ultrasonography 2018;37(4):307-314
PURPOSE: The purpose of this study was to evaluate the ultrasonographic features of pure ductal carcinoma in situ (DCIS) of the breast and to evaluate the correlations of ultrasonographic features with pathologic and biological features. METHODS: A total of 141 lesions in 138 women with pure DCIS who underwent preoperative breast ultrasonography were retrospectively reviewed. Ultrasonographic features were analyzed using the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) ultrasonography lexicon and the diagnostic criteria of the Japan Society of Ultrasonics in Medicine. Pathologic features including the nuclear grade and presence of comedonecrosis were evaluated. Biological markers including estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) status, as well as the Ki-67 index, were recorded. Ultrasonographic features were compared with pathologic findings and biological markers using the chi-square test. P-values of < 0.05 were considered to indicate statistical significance. RESULTS: Of the 141 lesions, 75 (53.2%) were mass lesions, 56 (39.7%) were non-mass lesions, and 10 (7.1%) were not visible. The most common feature of the mass pattern was a mass with irregular shape (32.6%), an indistinct margin (27.7%), and hypoechogenicity (37.6%). Microcalcifications were observed in 48 cases (36.6%) as an associated feature. Calcifications outside of a mass were more common than calcifications within a mass. Ultrasonographic microcalcifications and ductal changes were frequently observed in non-mass lesions. Ultrasonographic non-mass lesions were associated with high-grade DCIS (P=0.004) and the presence of comedonecrosis (P=0.006). Microcalcifications were significantly associated with high-grade DCIS (P < 0.001), the presence of comedonecrosis (P < 0.001), an elevated Ki-67 (P < 0.001), and HER2 positivity (P=0.003). CONCLUSION: The most common ultrasonographic feature of pure DCIS was an irregular, hypoechoic mass with an indistinct margin. Ultrasonographic microcalcifications and ductal changes were more frequent in non-mass lesions, which were correlated with poor prognostic factors, such as a high nuclear grade, comedonecrosis, HER2 positivity, and an elevated Ki-67 index.
Biomarkers*
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Breast*
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Carcinoma, Ductal*
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Carcinoma, Intraductal, Noninfiltrating*
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Estrogens
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Female
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Humans
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Information Systems
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Japan
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Pathology
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Receptor, Epidermal Growth Factor
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Receptors, Progesterone
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Retrospective Studies
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Ultrasonics
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Ultrasonography
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Ultrasonography, Mammary
6.Evaluation of the Public Health Emergency Response to the COVID-19 Pandemic in Daegu, Korea During the First Half of 2020
Hwajin LEE ; Keon-Yeop KIM ; Jong-Yeon KIM ; Sin KAM ; Kyeong Soo LEE ; Jung Jeung LEE ; Nam Soo HONG ; Tae-Yoon HWANG
Journal of Preventive Medicine and Public Health 2022;55(4):360-370
Objectives:
This study evaluated the response in Daegu, Korea to the first wave of the coronavirus disease 2019 (COVID-19) pandemic according to a public health emergency response model.
Methods:
After an examination of the official data reported by the city of Daegu and the Korea Centers for Disease Control and Prevention, as well as a literature review and advisory meetings, we chose a response model. Daegu’s responses were organized into 4 phases and evaluated by applying the response model.
Results:
In phase 1, efforts were made to block further transmission of the virus through preemptive testing of a religious group. In phase 2, efforts were concentrated on responding to mass infections in high-risk facilities. Phase 3 involved a transition from a high-intensity social distancing campaign to a citizen participation–based quarantine system. The evaluation using the response model revealed insufficient systematic preparation for a medical surge. In addition, an incorporated health-related management system and protection measures for responders were absent. Nevertheless, the city encouraged the participation of private hospitals and developed a severity classification system. Citizens also played active roles in the pandemic response by practicing social distancing.
Conclusions
This study employed the response model to evaluate the early response in Daegu to the COVID-19 pandemic and revealed areas in need of improvement or maintenance. Based on the study results, creation of a systematic model is necessary to prepare for and respond to future public health emergencies like the COVID-19 pandemic.
7.Exendin-4 Improves Nonalcoholic Fatty Liver Disease by Regulating Glucose Transporter 4 Expression in ob/ob Mice.
Seok KIM ; Jaehoon JUNG ; Hwajin KIM ; Rok Won HEO ; Chin Ok YI ; Jung Eun LEE ; Byeong Tak JEON ; Won Ho KIM ; Jong Ryeal HAHM ; Gu Seob ROH
The Korean Journal of Physiology and Pharmacology 2014;18(4):333-339
Exendin-4 (Ex-4), a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been known to reverse hepatic steatosis in ob/ob mice. Although many studies have evaluated molecular targets of Ex-4, its mechanism of action on hepatic steatosis and fibrosis has not fully been determined. In the liver, glucose transporter 4 (GLUT4) is mainly expressed in hepatocytes, endothelial cells and hepatic stellate cells (HSCs). In the present study, the effects of Ex-4 on GLUT4 expression were determined in the liver of ob/ob mice. Ob/ob mice were treated with Ex-4 for 10 weeks. Serum metabolic parameters, hepatic triglyceride levels, and liver tissues were evaluated for hepatic steatosis. The weights of the whole body and liver in ob/ob mice were reduced by long-term Ex-4 treatment. Serum metabolic parameters, hepatic steatosis, and hepatic fibrosis in ob/ob mice were reduced by Ex-4. Particularly, Ex-4 improved hepatic steatosis by enhancing GLUT4 via GLP-1R activation in ob/ob mice. Ex-4 treatment also inhibited hepatic fibrosis by decreasing expression of connective tissue growth factor in HSCs of ob/ob mice. Our data suggest that GLP-1 agonists exert a protective effect on hepatic steatosis and fibrosis in obesity and type 2 diabetes.
Animals
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Connective Tissue Growth Factor
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Endothelial Cells
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Fatty Liver*
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Fibrosis
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Glucagon-Like Peptide 1
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Glucagon-Like Peptide-1 Receptor
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Glucose Transport Proteins, Facilitative*
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Hepatic Stellate Cells
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Hepatocytes
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Liver
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Mice*
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Obesity
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Triglycerides
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Weights and Measures