1.β-PIX-d, a Member of the ARHGEF7 Guanine Nucleotide Exchange Factor Family, Activates Rac1 and Induces Neuritogenesis in Primary Cortical Neurons
Seunghyuk KIM ; Heeyoung PARK ; Jieun KANG ; Seunghyuk CHOI ; Ali SADRA ; Sung-Oh HUH
Experimental Neurobiology 2024;33(5):215-224
β-PIX, a Rac1/Cdc42-specific guanine nucleotide exchange factor, is known to regulate actin cytoskeleton remodeling during cell migration. In this study, we investigated the effects of β-PIX-d, an isoform of β-PIX, on neocortical development and neuritogenesis. Overexpression of β-PIX-d in the embryonic neocortex induced increased cell clusters and enhanced neurite outgrowth in cortical neurons. Following in utero electroporation of β-PIX-d expression vectors into neuronal progenitor cells at embryonic day 13.5 (E13.5), histological analysis at postnatal day 0 (P0) revealed the presence of clustered neurons and neurites outside of the marginal zone (MZ). Immunofluorescence staining with the neuronal marker TuJ1 confirmed that the clustered structures were predominantly composed of neurons. Layer-specific marker analysis further demonstrated the misplacement of layer V-VI neurons into layer I and the subarachnoid space. In primary neocortical cultures, β-PIX-d overexpression promoted neuritogenesis and increased Rac1 activity, as detected by pull-down assays. These findings suggest that β-PIX-d and Rac1 interactions play a critical role in the formation of neocortical clustering and the regulation of neuritogenesis.
2.β-PIX-d, a Member of the ARHGEF7 Guanine Nucleotide Exchange Factor Family, Activates Rac1 and Induces Neuritogenesis in Primary Cortical Neurons
Seunghyuk KIM ; Heeyoung PARK ; Jieun KANG ; Seunghyuk CHOI ; Ali SADRA ; Sung-Oh HUH
Experimental Neurobiology 2024;33(5):215-224
β-PIX, a Rac1/Cdc42-specific guanine nucleotide exchange factor, is known to regulate actin cytoskeleton remodeling during cell migration. In this study, we investigated the effects of β-PIX-d, an isoform of β-PIX, on neocortical development and neuritogenesis. Overexpression of β-PIX-d in the embryonic neocortex induced increased cell clusters and enhanced neurite outgrowth in cortical neurons. Following in utero electroporation of β-PIX-d expression vectors into neuronal progenitor cells at embryonic day 13.5 (E13.5), histological analysis at postnatal day 0 (P0) revealed the presence of clustered neurons and neurites outside of the marginal zone (MZ). Immunofluorescence staining with the neuronal marker TuJ1 confirmed that the clustered structures were predominantly composed of neurons. Layer-specific marker analysis further demonstrated the misplacement of layer V-VI neurons into layer I and the subarachnoid space. In primary neocortical cultures, β-PIX-d overexpression promoted neuritogenesis and increased Rac1 activity, as detected by pull-down assays. These findings suggest that β-PIX-d and Rac1 interactions play a critical role in the formation of neocortical clustering and the regulation of neuritogenesis.
3.β-PIX-d, a Member of the ARHGEF7 Guanine Nucleotide Exchange Factor Family, Activates Rac1 and Induces Neuritogenesis in Primary Cortical Neurons
Seunghyuk KIM ; Heeyoung PARK ; Jieun KANG ; Seunghyuk CHOI ; Ali SADRA ; Sung-Oh HUH
Experimental Neurobiology 2024;33(5):215-224
β-PIX, a Rac1/Cdc42-specific guanine nucleotide exchange factor, is known to regulate actin cytoskeleton remodeling during cell migration. In this study, we investigated the effects of β-PIX-d, an isoform of β-PIX, on neocortical development and neuritogenesis. Overexpression of β-PIX-d in the embryonic neocortex induced increased cell clusters and enhanced neurite outgrowth in cortical neurons. Following in utero electroporation of β-PIX-d expression vectors into neuronal progenitor cells at embryonic day 13.5 (E13.5), histological analysis at postnatal day 0 (P0) revealed the presence of clustered neurons and neurites outside of the marginal zone (MZ). Immunofluorescence staining with the neuronal marker TuJ1 confirmed that the clustered structures were predominantly composed of neurons. Layer-specific marker analysis further demonstrated the misplacement of layer V-VI neurons into layer I and the subarachnoid space. In primary neocortical cultures, β-PIX-d overexpression promoted neuritogenesis and increased Rac1 activity, as detected by pull-down assays. These findings suggest that β-PIX-d and Rac1 interactions play a critical role in the formation of neocortical clustering and the regulation of neuritogenesis.
4.β-PIX-d, a Member of the ARHGEF7 Guanine Nucleotide Exchange Factor Family, Activates Rac1 and Induces Neuritogenesis in Primary Cortical Neurons
Seunghyuk KIM ; Heeyoung PARK ; Jieun KANG ; Seunghyuk CHOI ; Ali SADRA ; Sung-Oh HUH
Experimental Neurobiology 2024;33(5):215-224
β-PIX, a Rac1/Cdc42-specific guanine nucleotide exchange factor, is known to regulate actin cytoskeleton remodeling during cell migration. In this study, we investigated the effects of β-PIX-d, an isoform of β-PIX, on neocortical development and neuritogenesis. Overexpression of β-PIX-d in the embryonic neocortex induced increased cell clusters and enhanced neurite outgrowth in cortical neurons. Following in utero electroporation of β-PIX-d expression vectors into neuronal progenitor cells at embryonic day 13.5 (E13.5), histological analysis at postnatal day 0 (P0) revealed the presence of clustered neurons and neurites outside of the marginal zone (MZ). Immunofluorescence staining with the neuronal marker TuJ1 confirmed that the clustered structures were predominantly composed of neurons. Layer-specific marker analysis further demonstrated the misplacement of layer V-VI neurons into layer I and the subarachnoid space. In primary neocortical cultures, β-PIX-d overexpression promoted neuritogenesis and increased Rac1 activity, as detected by pull-down assays. These findings suggest that β-PIX-d and Rac1 interactions play a critical role in the formation of neocortical clustering and the regulation of neuritogenesis.
5.Superior mediastinal enlargement after trauma.
Seunghyuk MOON ; Hyeontae KIM ; Sootaek UH ; Yeontae CHUNG ; Yonghun KIM ; Choonsik PARK
Tuberculosis and Respiratory Diseases 1991;38(3):324-326
No abstract available.
6.Metastasizing Pleomorphic Adenoma in Right Lung: A case report.
Won Sang CHUNG ; Hyuck KIM ; Seunghyuk NAM ; Jeong Ho KANG ; Young Hak KIM ; Eung Soo KIM
The Korean Journal of Thoracic and Cardiovascular Surgery 2007;40(2):143-146
A metastasizing pleomorphic adenoma originating from the parotid gland is a rare form of neoplasm. The neoplasm is a histologically benign, but clinically controversial entity. Herein, a case report of a pleuro-pneumonectomy of a metastasizing pleomorphic adenoma in the right lung is described. A 57-year-old man, who underwent resection of parotid gland due to a pleomorphic adenoma, presented with multiple metastases on the right lung, mediastinum, pericardium and intercostal muscle. The metastatic lesions were composed of a benign pleomorphic structure.
Adenoma, Pleomorphic*
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Humans
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Intercostal Muscles
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Lung*
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Mediastinum
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Metastasectomy
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Middle Aged
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Neoplasm Metastasis
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Parotid Gland
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Pericardium
7.Right Pulmonary Artery Agenesis: A case report.
Hyuck KIM ; Jeong Ho KANG ; Jang Seop WEE ; Young Hak KIM ; Won Sang CHUNG ; Seunghyuk NAM
The Korean Journal of Thoracic and Cardiovascular Surgery 2007;40(1):52-55
Unilateral pulmonary artery agenesis is a rare congenital malformation usually associated with other cardiovascular anomaly such as Tetralogy of Fallot. Isolated pulmonary artery agenesis is very rare, and usually asymptomatic. It is usually highly suspected by routine chest X-ray, and associated symptoms are hemoptysis, blood tinged sputum, repeated pulmonary infection, and dyspnea on exertion. We have recently experienced the right pulmonary artery agenesis in 27 year-old male patient, complaining of minimal hemoptysis and sustained blood tinged sputum. He was successfully treated by right pneumonectomy, so we report this case with the review of associated literature.
Adult
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Dyspnea
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Hemoptysis
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Humans
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Male
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Pneumonectomy
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Pulmonary Artery*
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Sputum
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Tetralogy of Fallot
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Thorax
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Tolnaftate
8.Analysis of Postoperative Coronary Angiography in Symptomatic Patients.
Young Hak KIM ; San Woong HAN ; Jeong Ho KANG ; Won Sang CHUNG ; Hyuck KIM ; Chul Burm LEE ; Soon Ho CHON ; Seunghyuk NAM
The Korean Journal of Thoracic and Cardiovascular Surgery 2006;39(10):759-764
BACKGROUND: We analyzed post-operative angiography performed in symptomatic patients to evaluate the patency rates and the roles of grafts. MATERIAL AND METHOD: We reviewed 52 (15%) coronary angiograms performed for recurrent angina after prior coronary artery bypass surgery from January 1995 to June 2005. A total of 345 patients underwent coronary artery bypass surgery during this period. There were 41 men and 11 women and the mean age was 64.07+/-15.58 years. The median period from operation to re-angiogram was 68.5 months (range, 1 to 126 months). The numbers of grafts and peripheral anastomoses were 42 and 43 for internal thoracic artery (ITA), 14 and 20 for radial artery (RA), and 49 and 89 for saphenous vein. The mean number of anastomosis was 2.9 per patient. RESULT: The patency rates of ITA, RA and saphenous vein graft (SVG) were 37/43 (86%), 17/20 (85%) and 34/89 (38.2%). The patency rate of arterial grafts was significantly higher than that of SVG (p<0.001) and the patency rate of the RA was comparable to that of ITA (p=0.912). The patency rate of sequential SVGs was higher than that of single SVG (40.3% vs 31.8%, p=0.478) and the patency rate of proximal segments in sequential anastomosis was higher than that in single anastomsis (55.6% vs 31.8%, p=0.097), but statistically not significant. CONCLUSION: Arterial grafts have markedly superior patency rates than SVGs, so consideration should be given to the vigorous use of arterial grafts. The patency rate of the RA was comparable to that of ITA.
Angiography
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Coronary Angiography*
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Coronary Artery Bypass
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Female
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Humans
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Male
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Mammary Arteries
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Radial Artery
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Saphenous Vein
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Transplants
9.Farnesylation-defective Rheb Increases Axonal Length Independently of mTORC1 Activity in Embryonic Primary Neurons
Seunghyuk CHOI ; Ali SADRA ; Jieun KANG ; Jae Ryun RYU ; June Hoan KIM ; Woong SUN ; Sung Oh HUH
Experimental Neurobiology 2019;28(2):172-182
Rheb (Ras homolog enriched in the brain) is a small GTPase protein that plays an important role in cell signaling for development of the neocortex through modulation of mTORC1 (mammalian-target-of-rapamycin-complex-1) activity. mTORC1 is known to control various biological processes including axonal growth in forming complexes at the lysosomal membrane compartment. As such, anchoring of Rheb on the lysosomal membrane via the farnesylation of Rheb at its cysteine residue (C180) is required for its promotion of mTOR activity. To test the significance of Rheb farnesylation, we overexpressed a farnesylation mutant form of Rheb, Rheb C180S, in primary rat hippocampal neurons and also in mouse embryonic neurons using in utero electroporation. Interestingly, we found that Rheb C180S maintained promotional effect of axonal elongation similar to the wild-type Rheb in both test systems. On the other hand, Rheb C180S failed to exhibit the multiple axon-promoting effect which is found in wild-type Rheb. The levels of phospho-4EBP1, a downstream target of mTORC1, were surprisingly increased in Rheb C180S transfected neurons, despite the levels of phosphorylated mTOR being significantly decreased compared to control vector transfectants. A specific mTORC1 inhibitor, rapamycin, also could not completely abolish axon elongation characteristics of Rheb C180S in transfected cells. Our data suggests that Rheb in a non-membrane compartment can promote the axonal elongation via phosphorylation of 4EBP1 and through an mTORC1-independent pathway.
Animals
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Axons
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Biological Processes
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Cysteine
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Electroporation
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GTP Phosphohydrolases
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Hand
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Membranes
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Mice
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Neocortex
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Neurons
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Phosphorylation
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Prenylation
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Protein Prenylation
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Rats
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Sirolimus
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TOR Serine-Threonine Kinases