• Title/Summary/Keyword: Knockout

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Cathelicidin-related Antimicrobial Peptide Contributes to Host Immune Responses Against Pulmonary Infection with Acinetobacter baumannii in Mice

  • Min-Jung Kang;Ah-Ra Jang;Ji-Yeon Park;Jae-Hun Ahn;Tae-Sung Lee;Dong-Yeon Kim;Do-Hyeon Jung;Eun-Jung Song;Jung Joo Hong;Jong-Hwan Park
    • IMMUNE NETWORK
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    • v.20 no.3
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    • pp.25.1-25.13
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    • 2020
  • Acinetobacter baumannii is known for its multidrug antibiotic resistance. New approaches to treating drug-resistant bacterial infections are urgently required. Cathelicidin-related antimicrobial peptide (CRAMP) is a murine antimicrobial peptide that exerts diverse immune functions, including both direct bacterial cell killing and immunomodulatory effects. In this study, we sought to identify the role of CRAMP in the host immune response to multidrug-resistant Acinetobacter baumannii. Wild-type (WT) and CRAMP knockout mice were infected intranasally with the bacteria. CRAMP-/- mice exhibited increased bacterial colony-forming units (CFUs) in bronchoalveolar lavage (BAL) fluid after A. baumannii infection compared to WT mice. The loss of CRAMP expression resulted in a significant decrease in the recruitment of immune cells, primarily neutrophils. The levels of IL-6 and CXCL1 were lower, whereas the levels of IL-10 were significantly higher in the BAL fluid of CRAMP-/- mice compared to WT mice 1 day after infection. In an in vitro assay using thioglycollate-induced peritoneal neutrophils, the ability of bacterial phagocytosis and killing was impaired in CRAMP-/- neutrophils compared to the WT cells. CRAMP was also essential for the production of cytokines and chemokines in response to A. baumannii in neutrophils. In addition, the A. baumannii-induced inhibitor of κB-α degradation and phosphorylation of p38 MAPK were impaired in CRAMP-/- neutrophils, whereas ERK and JNK phosphorylation was upregulated. Our results indicate that CRAMP plays an important role in the host defense against pulmonary infection with A. baumannii by promoting the antibacterial activity of neutrophils and regulating the innate immune responses.

Natural Killer and CD8 T Cells Contribute to Protection by Formalin Inactivated Respiratory Syncytial Virus Vaccination under a CD4-Deficient Condition

  • Eun-Ju Ko;Youri Lee;Young-Tae Lee;Hye Suk Hwang;Yoonsuh Park;Ki-Hye Kim;Sang-Moo Kang
    • IMMUNE NETWORK
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    • v.20 no.6
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    • pp.51.1-51.17
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    • 2020
  • Respiratory syncytial virus (RSV) causes severe pulmonary disease in infants, young children, and the elderly. Formalin inactivated RSV (FI-RSV) vaccine trials failed due to vaccine enhanced respiratory disease, but the underlying immune mechanisms remain not fully understood. In this study, we have used wild type C57BL/6 and CD4 knockout (CD4KO) mouse models to better understand the roles of the CD4 T cells and cellular mechanisms responsible for enhanced respiratory disease after FI-RSV vaccination and RSV infection. Less eosinophil infiltration and lower pro-inflammatory cytokine production were observed in FI-RSV vaccinated CD4KO mice after RSV infection compared to FI-RSV vaccinated C57BL/6 mice. NK cells and cytokine-producing CD8 T cells were recruited at high levels in the airways of CD4KO mice, correlating with reduced respiratory disease. Depletion studies provided evidence that virus control was primarily mediated by NK cells whereas CD8 T cells contributed to IFN-γ production and less eosinophilic lung inflammation. This study demonstrated the differential roles of effector CD4 and CD8 T cells as well as NK cells, in networking with other inflammatory infiltrates in RSV disease in immune competent and CD4-deficient condition.

Ginsenoside Rg1 alleviates vascular remodeling in hypoxia-induced pulmonary hypertension mice through the calpain-1/STAT3 signaling pathway

  • Chenyang Ran;Meili Lu;Fang Zhao;Yi Hao;Xinyu Guo;Yunhan Li;Yuhong Su;Hongxin Wang
    • Journal of Ginseng Research
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    • v.48 no.4
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    • pp.405-416
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    • 2024
  • Background: Hypoxic pulmonary hypertension (HPH) is the main pathological change in vascular remodeling, a complex cardiopulmonary disease caused by hypoxia. Some research results have shown that ginsenoside Rg1 (Rg1) can improve vascular remodeling, but the effect and mechanism of Rg1 on hypoxia-induced pulmonary hypertension are not clear. The purpose of this study was to discuss the potential mechanism of action of Rg1 on HPH. Methods: C57BL/6 mice, calpain-1 knockout mice and Pulmonary artery smooth muscle cells (PASMCs) were exposed to a low oxygen environment with or without different treatments. The effect of Rg1 and calpain-1 silencing on inflammation, fibrosis, proliferation and the protein expression levels of calpain-1, STAT3 and p-STAT3 were determined at the animal and cellular levels. Results: At the mouse and cellular levels, hypoxia promotes inflammation, fibrosis, and cell proliferation, and the expression of calpain-1 and p-STAT3 is also increased. Ginsenoside Rg1 administration and calpain-1 knockdown, MDL-28170, and HY-13818 treatment showed protective effects on hypoxia-induced inflammation, fibrosis, and cell proliferation, which may be associated with the downregulation of calpain-1 and p-STAT3 expression in mice and cells. In addition, overexpression of calpain 1 increased p-STAT3 expression, accelerating the onset of inflammation, fibrosis and cell proliferation in hypoxic PASMCs. Conclusion: Ginsenoside Rg1 may ameliorate hypoxia-induced pulmonary vascular remodeling by suppressing the calpain-1/STAT3 signaling pathway.

The Essential Function of miR-5739 in Embryonic Muscle Development

  • Ji-Heon Lee;Min Sup Kim;Jin-seop Lee;Dong Hyun Lee;Chansol Park;Dong Hyuk Lee;Eun-Young Kim;Hyung Min Chung
    • International Journal of Stem Cells
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    • v.16 no.2
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    • pp.145-155
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    • 2023
  • Background and Objectives: Embryologically, mesodermal development is closely related to the development of various organs such as muscles, blood vessels, and hearts, which are the main organs that make up the body. However, treatment for mesoderm developmental disorders caused by congenital or acquired factors has so far relied on surgery and drug treatment for symptom relief, and more fundamentally, treatment for mesoderm developmental disorders is needed. Methods and Results: In our study, microRNA (miRNA), which plays an important role in the mesoderm development process, was identified and the developmental function was evaluated. miRNAs consist of small nucleotides, which act as transcription factors that bind to the 3' untranslated region and suppressed target gene expression. We constructed the human embryonic stem cell (hESC) knockout cell line and analyzed the function and characteristics of miR-5739, which plays an important role in mesoderm lineage. miR-5739 acts as a transcription factor targeting SMA, Brachyury T, Hand1, which controls muscle proliferation and differentiation, and KDR gene, which regulates vessel formation in vitro. In vivo results suggest a role in regulating muscle proliferation and differentiation. Gene ontology analysis confirmed that the miR-5739 is closely related to genes that regulate muscle and vessel proliferation and differentiation. Importantly, abnormal expression of miR-5739 was detected in somatic cells derived from patients with congenital muscle disease. Conclusions: Our study demonstrate that miR-5739 gene function significantly affects transcriptional circuits that regulate muscle and vascular differentiation during embryonic development.

Embryonic Stem Cells Lacking DNA Methyltransferases Differentiate into Neural Stem Cells that Are Defective in Self-Renewal

  • Bong Jong Seo;Tae Kyung Hong;Sang Hoon Yoon;Jae Hoon Song;Sang Jun Uhm;Hyuk Song;Kwonho Hong;Hans Robert Scholer;Jeong Tae Do
    • International Journal of Stem Cells
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    • v.16 no.1
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    • pp.44-51
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    • 2023
  • Background and Objectives: DNA methyltransferases (Dnmts) play an important role in regulating DNA methylation during early developmental processes and cellular differentiation. In this study, we aimed to investigate the role of Dnmts in neural differentiation of embryonic stem cells (ESCs) and in maintenance of the resulting neural stem cells (NSCs). Methods and Results: We used three types of Dnmt knockout (KO) ESCs, including Dnmt1 KO, Dnmt3a/3b double KO (Dnmt3 DKO), and Dnmt1/3a/3b triple KO (Dnmt TKO), to investigate the role of Dnmts in neural differentiation of ESCs. All three types of Dnmt KO ESCs could form neural rosette and differentiate into NSCs in vitro. Interestingly, however, after passage three, Dnmt KO ESC-derived NSCs could not maintain their self-renewal and differentiated into neurons and glial cells. Conclusions: Taken together, the data suggested that, although deficiency of Dnmts had no effect on the differentiation of ESCs into NSCs, the latter had defective maintenance, thereby indicating that Dnmts are crucial for self-renewal of NSCs.

Ellagic acid, a functional food component, ameliorates functionality of reverse cholesterol transport in murine model of atherosclerosis

  • Sin-Hye Park;Min-Kyung Kang;Dong Yeon Kim;Soon Sung Lim;Il-Jun Kang;Young-Hee Kang
    • Nutrition Research and Practice
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    • v.18 no.2
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    • pp.194-209
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    • 2024
  • BACKGROUND/OBJECTIVES: High levels of plasma low-density lipoprotein (LDL) cholesterol are an important determinant of atherosclerotic lesion formation. The disruption of cholesterol efflux or reverse cholesterol transport (RCT) in peripheral tissues and macrophages may promote atherogenesis. The aim of the current study was to examine whether bioactive ellagic acid, a functional food component, improved RCT functionality and high-density lipoprotein (HDL) function in diet-induced atherogenesis of apolipoproteins E (apoE) knockout (KO) mice. MATERIALS/METHODS: Wild type mice and apoE KO mice were fed a high-cholesterol Paigen diet for 10 weeks to induce hypercholesterolemia and atherosclerosis, and concomitantly received 10 mg/kg ellagic acid via gavage. RESULTS: Supplying ellagic acid enhanced induction of apoE and ATP-binding cassette (ABC) transporter G1 in oxidized LDL-exposed macrophages, facilitating cholesterol efflux associated with RCT. Oral administration of ellagic acid to apoE KO mice fed on Paigen diet improved hypercholesterolemia with reduced atherogenic index. This compound enhanced the expression of ABC transporters in peritoneal macrophages isolated from apoE KO mice fed on Paigen diet, indicating increased cholesterol efflux. Plasma levels of cholesterol ester transport protein and phospholipid transport protein involved in RCT were elevated in mice lack of apoE gene, which was substantially reduced by supplementing ellagic acid to Paigen diet-fed mice. In addition, ellagic acid attenuated hepatic lipid accumulation in apoE KO mice, evidenced by staining of hematoxylin and eosin and oil red O. Furthermore, the supplementation of 10 mg/kg ellagic acid favorably influenced the transcriptional levels of hepatic LDL receptor and scavenger receptor-B1 in Paigen diet-fed apoE KO mice. CONCLUSION: Ellagic acid may be an athero-protective dietary compound encumbering diet-induced atherogenesis though improving the RCT functionality.

Generation of ints14 Knockout Zebrafish using CRISPR/Cas9 for the Study of Development and Disease Mechanisms

  • Ji Hye Jung;Sanghoon Jeon;Heabin Kim;Seung-Hyun Jung
    • Development and Reproduction
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    • v.27 no.4
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    • pp.205-211
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    • 2023
  • INTS14/VWA9, a component of the integrator complex subunits, plays a pivotal role in regulating the fate of numerous nascent RNAs transcribed by RNA polymerase II, particularly in the biogenesis of small nuclear RNAs and enhancer RNAs. Despite its significance, a comprehensive mutation model for developmental research has been lacking. To address this gap, we aimed to investigate the expression patterns of INTS14 during zebrafish embryonic development. We generated ints14 mutant strains using the CRISPR/Cas9 system. We validated the gRNA activity by co-injecting Cas9 protein and a single guide RNA into fertilized zebrafish eggs, subsequently confirming the presence of a 6- or 9-bp deletion in the ints14 gene. In addition, we examined the two mutant alleles through PCR analysis, T7E1 assay, TA-cloning, and sequencing. For the first time, we used the CRISPR/Cas9 system to create a model in which some sequences of the ints14 gene were removed. This breakthrough opens new avenues for in-depth exploration of the role of ints14 in animal diseases. The mutant strains generated in this study can provide a valuable resource for further investigations into the specific consequences of ints14 gene deletion during zebrafish development. This research establishes a foundation for future studies exploring the molecular mechanisms underlying the functions of ints14, its interactions with other genes or proteins, and its broader implications for biological processes.

Microarray profile of hypothalamic gene expression with acupuncture at acupoint ST36 in carrageenan induced inflammation in Stat 6 knockout mice (Carrageenan으로 염증을 유도한 Stat 6 유전자제거 생쥐의 족삼리 침치료에 대한 시상하부 유전자의 마이크로어레이 프로파일)

  • Park, Hi-Joon;Um, Yoon-Kyung;Jung, Kyung-Hee;Kim, Soo-Cheol;Han, Mi-Young;Hong, Mee-Suk
    • Korean Journal of Acupuncture
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    • v.24 no.2
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    • pp.129-139
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    • 2007
  • 목적 : Signal transducers and activators of transcription 6 (Stat 6) 유전자는 면역세포의 발달에 있어서 중요한 유전인자이며, IL-4와 같은 사이토카인에 의해 유전자 발현이 조절된다. 본 연구에서는 Stat 6 유전자 제거 생쥐와 정상 (wild type, W/T) 생쥐에 carrageenan으로 염증을 유도한 후 족삼리에 침치료를 시행하여 시상하부에서의 유전자 발현 양상을 분석하고자 하였다. 방 법 : BALB/c (W/T, n=12) and BALB/c-Stat 6 유전자 제거 생쥐 (n=12)의 발뒤꿈치 표피에 1% carrageenan을 30 ul 주사하여 염증을 유도하였다. 침은 염증 유도 30분 후에 족삼리(ST36)에 시침하였으며, 염증유도에 의한 부종 증가율을 매 시간마다 측정하여 총 5시간동안 측정하였다. 마이크로에러이는 Stat 6 유전자 제거 생쥐를 염증 유발 군과 염증유발 후 침을 처치한 군으로 나누고, 시상하부를 적출하여 RNA를 분리한뒤 마이크로어레이 프로파일을 분석하였다. 결 과 : 염증에 의한 부종증가율을 비교한 결과, Stat 6 유전자 제거 생쥐 그룹의 부종증가율이 W/T 생쥐의 부종 증가율보다 약 50 % 정도 감소하였으며, 각 3, 4, 5시간째에 유의한 차이를 나타내었다. (각 p<0.05). W.T생쥐군과 Stat 6 유전자 제거 생쥐군 모두에서, 침 처치군이 염증 유발 군에 비해, 염증 유발 2시간 후부터 유의한 감소를 나타내었다. 시상하부의 유전자 발현을 관찰한 결과, 39개의 유전자가 3배 이상 감소하였으며, 19개의 유전자는 3배 이상 증가하였다. 결 론 : W/T 생쥐군과 Stat 6 유전자 제거 생쥐 모두에서 침의 진통효과는 나타나며, 이의 기전에는 시상하부에서의 침 치료에 의한 염증관련 유전자들의 감소와, 항염증과 관련된 유전자들이 증가가 관여하는 것으로 보인다., 10, 11), 내측전완피신경(TE5, 6, 7, 8, 9, 10, 11), 후상완피신경(TE12, 13), 상외측상완피신경(TE13), 외측쇄골상신경(TE14, 15),대이개신경(TE16, 17, 18, 19), 소후두신경(TE19, 20), 이개측두신경(TE20, 21, 22), 안면신경측두지(TE22, 23), 관골측두신경(TE23), 중층에 견갑상신경(TE15), 견갑배신경(TE15), 경상설골근신경(TE17), 후이개신경(TE18, 19, 20), 안면신경측두지(TE20, 21, 22), 심층에 후골간신경(TE5, 6, 7), 요골신경심지(TE8, 9, 12, 13), 견갑상신경(TE14), 액와신경가지(TE14), 부신경(TE16), 안면신경과 부신경가지(TE17), 설인신경(TE17), 설하신경(TE17), 경신경고리(TE17), 미주신경(TE17), 안면신경 (TE18). 3) 혈(血) 관(管) : 천층에 척측정맥배측지(TE1, 2), 고유수장지동맥배측지(TE1), 배측중수골동맥배측지(TE2), 배측중수골정맥(TE3), 척측피정맥(TE4, 5, 6, 7, 8, 9, 10, 11), 배측정맥궁(TE4), 부요측피정맥(TE6, 8, 9),요측피정맥(TE10, 11), 후견봉정맥가지(TE13, 14), 후이개동 ${\cdot}$ 정맥(TE16, 17, 18, 19, 20), 전이개동 ${\cdot}$ 정맥(TE20), 천측두동 ${\cdot}$ 정맥(TE22, 23), 중층에 후상완회선동맥(TE14), 견갑배동맥(TE15), 견갑상동맥(TE15),천측두동 ${\cdot}$ 정맥(TE21), 관골측두동 ${\cdot}$ 정맥(TE23), 심층에 배측중수골동맥(TE3), 배측수근동맥궁(TE4), 후골간동맥(TE4, 5, 6, 7, 8, 9), 전골간동맥(TE6, 7, 9)

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Ultrastructural analysis and quantification of autophagic vacuoles in wild-type and atg5 knockout mouse embryonic fibroblast cells (정상 및 atg5 유전자 제거 섬유아세포에서 자가포식체의 미세구조 및 이들의 정량적 분석)

  • Choi, Suin;Jeon, Pureum;Huh, Yang Hoon;Lee, Jin-A
    • Analytical Science and Technology
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    • v.31 no.5
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    • pp.208-218
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    • 2018
  • Autophagy is a cellular process whereby cytosolic materials or organelles are taken up in a double-membrane vesicle structure known as an autophagosome and transported into a lysosome for degradation. Although autophagy has been studied at the genetic, cellular, or biochemical level, systematic ultrastructural quantitative analysis of autophagosomes during the autophagy process by using transmission electron microscopy (TEM) has not yet been reported. In this study, we performed ultrastructural analysis of autophagosomes in wild-type (WT) mouse embryonic fibroblasts (MEFs) and autophagy essential gene (atg5) knockout (KO) MEFs. First, we performed ultrastructural analysis of autophagosomes in WT MEFs compared to atg5 KO MEFs in basal autophagy or starvation-induced autophagy. Although we observed phagopore, early, late autophagosomes, or autolysosomes in WT MEFs, atg5 KO MEFs had immature autophagosomes that showed incomplete closure. Upon starvation, late autophagosomes accumulated in WT MEFs while the number of immature autophagosomes significantly increased in atg5 KO MEF indicating that atg5 plays an important role in the maturation of autophagosomes. Next, we examined autophagosomes in the cell model expressing polyQ-expanded N-terminal fragment of huntingtin. Our TEM analysis indicates that the number of late autophagosomes was significantly increased in the cells expressing the mutant huntingtin, indicating that improving the fusion of autophagosome with lysosome may be effective to enhance autophagy for the treatment of Huntington's disease. Taken together, the results of our study indicate that ultrastructural and quantitative analysis of autophagosomes using TEM can be applied to various human cellular disease models, and that they will provide an important insight for cellular pathogenesis of human diseases associated with autophagy.

Activation Mechanism of Protein Kinase B by DNA-dependent Protein Kinase Involved in the DNA Repair System

  • Li, Yuwen;Piao, Longzhen;Yang, Keum-Jin;Shin, Sang-Hee;Shin, Eul-Soon;Park, Kyung-Ah;Byun, Hee-Sun;Won, Min-Ho;Choi, Byung-Lyul;Lee, Hyun-Ji;Kim, Young-Rae;Hong, Jang-Hee;Hur, Gang-Min;Kim, Jeong-Lan;Cho, Jae-Youl;Seok, Jeong-Ho;Park, Jong-Sun
    • Toxicological Research
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    • v.24 no.3
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    • pp.175-182
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    • 2008
  • DNA-dependent protein kinase(DNA-PK) is involved in joining DNA double-strand breaks induced by ionizing radiation or V(D)J recombination and is activated by DNA ends and composed of a DNA binding subunit, Ku, and a catalytic subunit, DNA-PKcs. It has been suggested that DNA-PK might be $2^{nd}$ upstream kinase for protein kinase B(PKB). In this report, we showed that Ser473 phosphorylation in the hydrophobic-motif of PKB is blocked in DNA-PK knockout mouse embryonic fibroblast cells(MEFs) following insulin stimulation, while there is no effect on Ser473 phosphorylation in DNA-PK wild type MEF cells. The observation is further confirmed in human glioblastoma cells expressing a mutant form of DNA-PK(M059J) and a wild-type of DNA-PK(M059K), indicating that DNA-PK is indeed important for PKB activation. Furthermore, the treatment of cells with doxorubicin, DNA-damage inducing agent, leads to PKB phosphorylation on Ser473 in control MEF cells while there is no response in DNA-PK knockout MEF cells. Together, these results proposed that DNA-PK has a potential role in insulin signaling as well as DNA-repair signaling pathway.