• Title/Summary/Keyword: Cell and their function

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VLSI-Implementation of the Virtual Scheduling Algorithm (Virtual Scheduling Algorithm의 VLSI 구현)

  • 전만영;박홍식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.1
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    • pp.144-154
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    • 1996
  • Proposed numerous algorithms for the policing function have mainly focused on their performances. Besides their performance evaluation, however, the VLSI-implementation of these algorithms is worth consideration as well. Although, no algorithms for the policing function have been standardized up to now, ITU-T I.371 suggests two examples of algorithms, the Virtual Scheduling Algorithm (VSA) and the Continuous State Leaky Bucket algorithm. In this paper, we suggest the architecture of a policing device implementing the VSA among various algorithms for the peak cell rate policing and discuss some issues on the implementation. We also present how to select the policing modes of the two devices used to realize various policing schemes and show the experimental results obtained under four different peak cell rate values to confirm that the device performs the policing function satisfactorily. We exploit the priority encoder to run the algorithm in parallel instead of sequentially, which reduces the operation time to a great extent.

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Nano-Precision Tweezers for Mechanosensitive Proteins and Beyond

  • Yang, Taehyun;Park, Celine;Rah, Sang-Hyun;Shon, Min Ju
    • Molecules and Cells
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    • v.45 no.1
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    • pp.16-25
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    • 2022
  • Mechanical forces play pivotal roles in regulating cell shape, function, and fate. Key players that govern the mechanobiological interplay are the mechanosensitive proteins found on cell membranes and in cytoskeleton. Their unique nanomechanics can be interrogated using single-molecule tweezers, which can apply controlled forces to the proteins and simultaneously measure the ensuing structural changes. Breakthroughs in high-resolution tweezers have enabled the routine monitoring of nanometer-scale, millisecond dynamics as a function of force. Undoubtedly, the advancement of structural biology will be further fueled by integrating static atomic-resolution structures and their dynamic changes and interactions observed with the force application techniques. In this minireview, we will introduce the general principles of single-molecule tweezers and their recent applications to the studies of force-bearing proteins, including the synaptic proteins that need to be categorized as mechanosensitive in a broad sense. We anticipate that the impact of nano-precision approaches in mechanobiology research will continue to grow in the future.

Exploration of Molecular Mechanisms of Diffuse Large B-cell Lymphoma Development Using a Microarray

  • Zhang, Zong-Xin;Shen, Cui-Fen;Zou, Wei-Hua;Shou, Li-Hong;Zhang, Hui-Ying;Jin, Wen-Jun
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.3
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    • pp.1731-1735
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    • 2013
  • Objective: We aimed to identify key genes, pathways and function modules in the development of diffuse large B-cell lymphoma (DLBCL) with microarray data and interaction network analysis. Methods: Microarray data sets for 7 DLBCL samples and 7 normal controls was downloaded from the Gene Expression Omnibus (GEO) database and differentially expressed genes (DEGs) were identified with Student's t-test. KEGG functional enrichment analysis was performed to uncover their biological functions. Three global networks were established for immune system, signaling molecules and interactions and cancer genes. The DEGs were compared with the networks to observe their distributions and determine important key genes, pathways and modules. Results: A total of 945 DEGs were obtained, 272 up-regulated and 673 down-regulated. KEGG analysis revealed that two groups of pathways were significantly enriched: immune function and signaling molecules and interactions. Following interaction network analysis further confirmed the association of DEGs in immune system, signaling molecules and interactions and cancer genes. Conclusions: Our study could systemically characterize gene expression changes in DLBCL with microarray technology. A range of key genes, pathways and function modules were revealed. Utility in diagnosis and treatment may be expected with further focused research.

Structure and Function of HtrA Family Proteins, the Key Players in Protein Quality Control

  • Kim, Dong-Young;Kim, Kyeong-Kyu
    • BMB Reports
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    • v.38 no.3
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    • pp.266-274
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    • 2005
  • High temperature requirement A (HtrA) and its homologues constitute the HtrA familiy proteins, a group of heat shock-induced serine proteases. Bacterial HtrA proteins perform crucial functions with regard to protein quality control in the periplasmic space, functioning as both molecular chaperones and proteases. In contrast to other bacterial quality control proteins, including ClpXP, ClpAP, and HslUV, HtrA proteins contain no regulatory components or ATP binding domains. Thus, they are commonly referred to as ATP-independent chaperone proteases. Whereas the function of ATP-dependent chaperone-proteases is regulated by ATP hydrolysis, HtrA exhibits a PDZ domain and a temperature-dependent switch mechanism, which effects the change in its function from molecular chaperone to protease. This mechanism is also related to substrate recognition and the fine control of its function. Structural and biochemical analyses of the three HtrA proteins, DegP, DegQ, and DegS, have provided us with clues as to the functional regulation of HtrA proteins, as well as their roles in protein quality control at atomic scales. The objective of this brief review is to discuss some of the recent studies which have been conducted regarding the structure and function of these HtrA proteins, and to compare their roles in the context of protein quality control.

The Aurora Kinase Inhibitor CYC116 Promotes the Maturation of Cardiomyocytes Derived from Human Pluripotent Stem Cells

  • Sijia, Ji;Wanzhi, Tu;Chenwen, Huang;Ziyang, Chen;Xinyue, Ren;Bingqing, He;Xiaoyan, Ding;Yuelei, Chen;Xin, Xie
    • Molecules and Cells
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    • v.45 no.12
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    • pp.923-934
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    • 2022
  • Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great potential in applications such as regenerative medicine, cardiac disease modeling, and in vitro drug evaluation. However, hPSC-CMs are immature, which limits their applications. During development, the maturation of CMs is accompanied by a decline in their proliferative capacity. This phenomenon suggests that regulating the cell cycle may facilitate the maturation of hPSC-CMs. Aurora kinases are essential kinases that regulate the cell cycle, the role of which is not well studied in hPSC-CM maturation. Here, we demonstrate that CYC116, an inhibitor of Aurora kinases, significantly promotes the maturation of CMs derived from both human embryonic stem cells (H1 and H9) and iPSCs (induced PSCs) (UC013), resulting in increased expression of genes related to cardiomyocyte function, better organization of the sarcomere, increased sarcomere length, increased number of mitochondria, and enhanced physiological function of the cells. In addition, a number of other Aurora kinase inhibitors have also been found to promote the maturation of hPSC-CMs. Our data suggest that blocking aurora kinase activity and regulating cell cycle progression may promote the maturation of hPSC-CMs.

Integrin 𝛼4 Positive Subpopulation in Adipose Derived Stem Cells Effectively Reduces Infarct Size through Enhanced Engraftment into Myocardial Infarction

  • Zihui Yuan;Juan Tan;Jian Wang
    • International Journal of Stem Cells
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    • v.17 no.1
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    • pp.70-79
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    • 2024
  • The efficacy of adipose-derived stem cells (ASCs) on myocardial infarction is limited due to poor survival and engraftment. Integrin-mediated cell adhesion is a prerequisite for its survival and homing. ASCs expressed insufficient integrin 𝛼4, limiting their homing capacity. This study aims to characterize integrin 𝛼4+ ASC subpopulation and investigate their therapeutic efficacy in myocardial infarction. We used fluorescence-activated cell sorting to harvest integrin 𝛼4+ ASCs subpopulation, which were characterized in vitro and transplanted into myocardial infarction model. Positron emission tomography imaging were performed to measure infarction size. Cardiac cine magnetic resonance imaging was used to evaluate heart contractile function. Compared with the unfractionated ASCs, integrin 𝛼4+ ASCs subpopulation secreted a higher level of angiogenic growth factors, migrated more rapidly, and exhibited a stronger anti-apoptotic capacity. Vascular cell adhesion molecule-1 was obviously up-regulated at 3 days after myocardial infarction, which interacted with integrin α4 receptor on the surface of ASCs to enhance the survival and adhesion. Thus, we implanted unfractionated ASCs or integrin α4+ ASCs subpopulation into the 3-day infarcted myocardium. Integrin α4+ ASCs subpopulation exhibited more robust engraftment into the infarcted myocardium. Integrin α4+ ASCs subpopulation more effectively decreased infarct size and strengthen cardiac function recovery than did the unfractionated ASCs. Integrin α4+ ASCs subpopulation is superior to unfractionated ASCs in ameliorating ischemic myocardial damage in animal model. Mechanistically, their more robust engraftment into the infarct area, higher migratory capacity and their increased release of paracrine factors contribute to enhanced tissue repair.

Adipogenic function of tetranectin mediated by enhancing mitotic clonal expansion via ERK signaling

  • Go, Seulgi;Park, Jihyun;Rahman, Safikur;Jin, Juno;Choi, Inho;Kim, Jihoe
    • BMB Reports
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    • v.54 no.7
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    • pp.374-379
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    • 2021
  • Tetranectin (TN), an adipogenic serum protein, enhances adipocyte differentiation, however, its functional mechanism has yet to be elucidated. In the present study, we investigated the adipogenic function of TN by using medium containing TN-depleted fetal bovine serum (TN-del-FBS) and recombinant mouse TN (mTN). The adipocyte differentiation of 3T3-L1 cells was significantly enhanced by mTN supplementation essentially at differentiation induction, which indicated a potential role of the protein in the early differentiation phase. The adipogenic effect of mTN was more significant with insulin in the differentiation induction cocktail, implicating their close functional relationship. mTN enhanced not only the proliferation of growing cells, but also mitotic clonal expansion (MCE) that is a prerequisite for adipocyte differentiation in the early phase. Consistently, mTN increased the phosphorylation of ERK in the early phase of adipocyte differentiation. Results of this study demonstrate that the adipogenic function of mTN is mediated by enhancing MCE via ERK signaling.

Microbial Components and Effector Molecules in T Helper Cell Differentiation and Function

  • Changhon Lee;Haena Lee;John Chulhoon Park;Sin-Hyeog Im
    • IMMUNE NETWORK
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    • v.23 no.1
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    • pp.7.1-7.27
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    • 2023
  • The mammalian intestines harbor trillions of commensal microorganisms composed of thousands of species that are collectively called gut microbiota. Among the microbiota, bacteria are the predominant microorganism, with viruses, protozoa, and fungi (mycobiota) making up a relatively smaller population. The microbial communities play fundamental roles in the maturation and orchestration of the immune landscape in health and disease. Primarily, the gut microbiota modulates the immune system to maintain homeostasis and plays a crucial role in regulating the pathogenesis and pathophysiology of inflammatory, neuronal, and metabolic disorders. The microbiota modulates the host immune system through direct interactions with immune cells or indirect mechanisms such as producing short-chain acids and diverse metabolites. Numerous researchers have put extensive efforts into investigating the role of microbes in immune regulation, discovering novel immunomodulatory microbial species, identifying key effector molecules, and demonstrating how microbes and their key effector molecules mechanistically impact the host immune system. Consequently, recent studies suggest that several microbial species and their immunomodulatory molecules have therapeutic applicability in preclinical settings of multiple disorders. Nonetheless, it is still unclear why and how a handful of microorganisms and their key molecules affect the host immunity in diverse diseases. This review mainly discusses the role of microbes and their metabolites in T helper cell differentiation, immunomodulatory function, and their modes of action.

A Study on the Morphogenesis of Human Fetal Hepatic Tissue (사람태아 간조직의 형태형성에 관한 연구)

  • Deung, Young-Kun;Kim, Dong-Heui
    • Applied Microscopy
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    • v.28 no.3
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    • pp.283-297
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    • 1998
  • Hemopoiesis and morphogenesis of the human fetal liver through from 10 to 32 weeks of gestation were investigated by light and electron microscopy. The results obtained were as follows. Hemopoiesis of fetal liver tissue was found from 10 to 32 weeks of gestation, but the hemopoiesis was decreased at 32 weeks of gestation. At the 32 weeks of gestation, matured erythrocytes were observed in the sinusoid, and formation of liver cell cord and portal triad were established. Differentiation of hepatic cell was characterized by the increase of amount of cell organelles within cytoplasm, decrease of hemopoietic cell, morphological change of nuclear envelope from folding form to round form during the developmental period. These results suggest that human fetal liver plays a hematopoietic function until bone marrow and spleen play their function, but morphology of liver at 32 weeks of gestation was differed with structure observed in liver of adult.

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Immune Regulatory Function of Cancer-Associated Fibroblasts in Non-small Cell Lung Cancer

  • Hyewon Lee;Mina Hwang;Seonae Jang;Sang-Won Um
    • Tuberculosis and Respiratory Diseases
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    • v.86 no.4
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    • pp.304-318
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    • 2023
  • Background: Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment and significantly contribute to immune evasion. We investigated the effects of CAFs on the immune function of CD4+ and CD8+ T cells in non-small cell lung cancer (NSCLC). Methods: We isolated CAFs and normal fibroblasts (NFs) from tumors and normal lung tissues of NSCLC patients, respectively. CAFs were co-cultured with activated T cells to evaluate their immune regulatory function. We investigated the effect of CAF conditioned medium (CAF-CM) on the cytotoxicity of T cells. CAFs were also co-cultured with activated peripheral blood mononuclear cells and further incubated with cyclooxygenase-2 (COX2) inhibitors to investigate the potential role of COX2 in immune evasion. Results: CAFs and NFs were isolated from the lung tissues (n=8) and lymph nodes (n=3) of NSCLC patients. Immune suppressive markers, such as COX2 and programmed death-ligand 1 (PD-L1), were increased in CAFs after co-culture with activated T cells. Interestingly, CAFs promoted the expression of programmed death-1 in CD4+ and CD8+ T cells, and strongly inhibited T cell proliferation in allogenic and autologous pairs of CAFs and T cells. CAF-CM decreased the cytotoxicity of T cells. COX2 inhibitors partially restored the proliferation of CD4+ and CD8+ T cells, and downregulated the expression of COX2, prostaglandin E synthase, prostaglandin E2, and PD-L1 in CAFs. Conclusion: CAFs promote immune evasion by suppressing the function of CD4+ and CD8+ T cells via their effects on COX2 and PD-L1 in NSCLC. The immunosuppressive function of CAFs could be alleviated by COX2 inhibitors.