• 생명과학회지
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• 제21권12호
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• pp.1795-1803
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• 2011

현대인의 고지방 식습관과 당뇨와 비만인구 증가로 인한 비 알코올성 지방간(nonalcoholic fatty liver)의 유병률(prevalence rate)은 나날이 증가하고 있는 추세이며, 특히 남성과 폐경기 여성에게서 두드러진다. 이런 성 특이적(sex-specific) 간질환의 차이는 여성 호르몬인 에스트로겐(estrogen)의 보호 역할 때문일 것으로 추정되고 있으나, 에스트로겐의 보호 기작을 포함한 지방간의 만성 간질환으로의 진행 메커니즘이 규명되어 있지 않기 때문에 간질환의 효과적인 예방 및 치료책이 없는 실정이다. 그런데 최근에 간 섬유화(fibrosis)를 포함한 만성 간질환의 진행에서 헤지호그(hedgehog) 신호전달계가 주요한 역할을 함이 보고되면서 손상된 간의 회복과 간질환 진행메커니즘 조절을 위한 연구대상으로서 주목 받고 있다. 헤지호그는 발생 및 분화를 조절하는 모포젠(morphogen)으로 성인의 건강한 간에서는 발현되지 않으나, 손상된 간에서 손상 정도에 비례하게 재 발현되며, 섬유화 유발세포인 근섬유아세포(myofibroblasts) 및 간 줄기세포(hepatic progenitor cells)의 활성 및 증식인자로 작용하여 지나친 간 섬유화를 일으킨다. 이에 반해, 에스트로겐은 간 성상세포(hepatic stellate cells)가 근섬유아세포로 활성화되는 것을 억제함으로써 간 섬유화를 막는 것으로 보고되고 있다. 간 섬유화에 대한 헤지호그와 에스트로겐의 상반된 역할 사이의 관련성은 아직 밝혀지지 않고 있으나, 간 섬유화 유발 물질인 오스테오폰틴(osteopontin) 발현에 대한 에스트로겐의 억제효과와 헤지호그에 의한 오스테오폰틴 발현 유도는 오스테오폰틴에 의해 매개되는 에스트로겐과 헤지호그 신호전달계 사이의 연관성을 시사한다. 따라서, 에스트로겐에 의한 헤지호그 신호전달계 조절 메커니즘을 규명하는 것은 간질환 환자에서의 간 섬유화 및 만성 질환으로의 진행을 억제할 수 있는 치료제 개발에 대한 기초 지식을 제공할 수 있다. 이를 위해 간 섬유화에 대한 헤지호그와 에스트로겐의 역할을 확실하게 이해하고, 상호 관련성 및 조절 기작을 밝히는 연구가 선행되어야 할 것이다.

• BMB Reports
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• 제32권2호
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• pp.103-111
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• 1999

Hh proteins represent a new signaling paradigm in metazoan development. In species ranging from fruit flies to humans, Hh proteins mediate multiple processes vital to appropriate pattern formation in the developing embryo. Hh proteins undergo an autoprocessing event in which the full-length protein is cleaved into N-terminal and C-terminal domains (Hh-N and Hh-C, respectively), and a cholesterol moiety becomes covalently attached to Hh-N. All known signaling activities of Hh proteins are mediated by Hh-N while both the cleavage and cholesterol transfer reactions are mediated by Hh-C. The cholesterol attached to Hh-N is required to retrict the range of Hh signaling and may be involved in ensuring appropriate reception of the Hh signal in target tissues. Disruptions of Hh signaling pathways lead to severe developmental defects in newborns and cancers in adults. While studies of Hh proteins have yielded a wealth of new insight into the molecular mechanisms of metazoan development, many outstanding questions concerning Hh signaling mechanisms ensure that unraveling the secrets of this molecule will keep scientists well entertained for the foreseeable future.

• 생명과학회지
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• 제30권11호
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• pp.973-982
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• 2020

본 연구는 지방구세포 감소를 위한 소재개발로 감국 추출물의 대표물질인 camphor가 갖는 지방구세포 분화억제효과를 관찰하였다. camphor의 세포독성을 확인하기 위해 3T3-L1 세포주를 이용하여 세포독성 측정을 1 day에서 10 day까지 확인하였고, 세포독성은 모두 없었다. PTCH siRNA를 처리 시 PTCH가 비활성되어 분화가 억제되었고, SMO siRNA 처리시 SMO가 비활성화되어 분화가 유도되었다. PTCH 억제는 SMO를 활성화시키는 기전으로HH 신호의 활성화가 지방구세포 분화를 억제시키는 것을 보여준다. FACS를 이용한 Gli1 발현은 KCTC 3237은 62.7±1.5%, camphor는 60.4±2.2% 로 분화된 세포 24.9±3.1% 보다 높은 것을 확인하였다. GC-MS에서 발효된 camphor의 구조변화는 없는 것으로 확인되었으나, KCTC 3237에서 15.41% 양적 증가를 확인했다. 또한camphor가 SMO를 과발현시키고, Gli1의 변화를 조절하였다. 따라서 감국 발효물의 생리활성 물질 중 향후 매커니즘 분석을 위한 활성물질인 camphor를 이용해 동물모델에서 비만억제 효과에 대한 자료가 더 필요할 것으로 여겨지며, 감국 추출물 및 발효물의 HH신호조절이 새로운 비만치료제로 개발될 수 있는 가능성을 제시하고자 한다.

• 한국발생생물학회지:발생과생식
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• 제23권4호
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• pp.305-311
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• 2019

Small intestine has a structure called villi that increases the mucosal surface area for nutrient absorption. Intricate and tight epithelial-mesenchymal interactions are required for villi development. These interactions are regulated by signaling molecules, physical forces, and epithelial deformation. Signaling molecules include hedgehog (Hh), bone morphogenetic protein (BMP) and Wnt ligands. The Hh ligand is expressed from the epithelium and binds to the underlying mesenchymal cells, resulting in aggregation into mesenchymal clusters. The clusters express BMP and Wnt ligands to control its size and spacing between clusters. The clusters then form villi. Despite the fact that the villi formation is studied extensively, we do not have a complete understanding. In addition, the recent study shows there is a great relationship between the overexpression of the Hh signal and development of cancer in the gastrointestinal tract. Therefore, signaling between epithelial and mesenchymal cells and their physical interactions will be discussed on this review.

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6201-6206
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• 2015

The epithelial-mesenchymal transition (EMT) is a cellular process though which an epithelial phenotype can be converted into a phenotype of mesenchymal cells. Under physiological conditions EMT is important for embryogenesis, organ development, wound repair and tissue remodeling. However, EMT may also be activated under pathologic conditions, especially in carcinogenesis and metastatic progression. Major signaling pathways involved in EMT include transforming growth factor ${\beta}(TGF-{\beta})$, Wnt, Notch, Hedgehog and other signaling pathways. These pathways are related to several transcription factors, including Twist, Smads and zinc finger proteins snail and slug. These interact with each other to provide crosstalk between the relevant signaling pathways. This review lays emphasis on studying the relationship between EMT and signaling pathways in carcinogenesis and metastatic progression.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.437-442
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• 2015

Aim: To establish a pancreatic cancer stem cell model using human pancreatic cancer cells in nude mice to provide a platform for pancreatic cancer stem cell research. Materials and Methods: To establish pancreatic cancer xenografts using human pancreatic cancer cell line SW1990, nude mice were randomly divided into control and gemcitabine groups. When the tumor grew to a volume of $125mm^3$, they treated with gemcitabine at a dose of 50mg/kg by intraperitoneal injection of 0.2ml in the gemcitabine group, while the mice in control group were treated with the same volume of normal saline. Gemcitabine was given 2 times a week for 3 times. When the model was established, the proliferation of pancreatic cancer stem cells was observed by clone formation assay, and the protein and/or mRNA expression of pancreatic stem cell surface markers including CD24, CD44, CD133, ALDH, transcription factors containing Oct-4, Sox-2, Nanog and Gli, the key nuclear transcription factor in Sonic Hedgehog signaling pathway was detected by Western blot and/or RT-PCR to verify the reliability of this model. Results: This model is feasible and safe. During the establishment, no mice died and the weight of nude mice maintained above 16.5g. The clone forming ability in gemcitabine group was stronger than that of the control group (p<0.01). In gemcitabine group, the protein expression of pancreatic cancer stem cell surface markers including CD44, and ALDH was up-regulated, the protein and mRNA expression of nuclear transcription factor including Oct-4, Sox-2 and Nanog was also significantly increased (P<0.01). In addition, the protein expression of key nuclear transcription factor in Sonic Hedgehog signaling pathway, Gli-1, was significantly enhanced (p<0.01). Conclusions: The pancreatic cancer stem cell model was successfully established using human pancreatic cancer cell line SW1990 in nude mice. Gemcitabine could enrich pancreatic cancer stem cells, simultaneously accompanied by the activation of Sonic Hedgehog signaling pathway.

• Molecules and Cells
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• 제41권3호
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• pp.224-233
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• 2018

Primary cilia are solitary, non-motile, axonemal microtubule-based antenna-like organelles that project from the plasma membrane of most mammalian cells and are implicated in transducing hedgehog signals during development. It was recently proposed that aberrant SHH signaling may be implicated in the progression of idiopathic pulmonary fibrosis (IPF). However, the distribution and role of primary cilia in IPF remains unclear. Here, we clearly observed the primary cilia in alveolar epithelial cells, fibroblasts, and endothelial cells of human normal lung tissue. Then, we investigated the distribution of primary cilia in human IPF tissue samples using immunofluorescence. Tissues from six IPF cases showed an increase in the number of primary cilia in alveolar cells and fibroblasts. In addition, we observed an increase in ciliogenesis related genes such as IFT20 and IFT88 in IPF. Since major components of the SHH signaling pathway are known to be localized in primary cilia, we quantified the mRNA expression of the SHH signaling components using qRT-PCR in both IPF and control lung. mRNA levels of SHH, the coreceptor SMO, and the transcription factors GLI1 and GLI2 were upregulated in IPF compared with control. Furthermore, the nuclear localization of GLI1 was observed mainly in alveolar epithelia and fibroblasts. In addition, we showed that defective KIF3A-mediated ciliary loss in human type II alveolar epithelial cell lines leads to disruption of SHH signaling. These results indicate that a significant increase in the number of primary cilia in IPF contributes to the upregulation of SHH signals.

• BMB Reports
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• 제45권8호
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• pp.427-432
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• 2012

Primary cilia, single hair-like appendage on the surface of the most mammalian cells, were once considered to be vestigial cellular organelles for a past century because of their tiny structure and unknown function. Although they lack ancestral motility function of cilia or flagella, they share common ground with multiciliated motile cilia and flagella on internal structure such as microtubule based nine outer doublets nucleated from the base of mother centrioles called basal body. Making cilia, ciliogenesis, in cells depends on the cell cycle stage due to reuse of centrioles for cell division forming mitotic spindle pole (M phase) and assembling cilia from basal body (starting G1 phase and maintaining most of interphase). Ciliary assembly required two conflicting processes such as assembly and disassembly and balance between these two processes determines the length of cilia. Both process required highly conserved transport system to supply needed substance to grow tip of cilia and bring ciliary turnover product back to the base of cilia using motor protein, kinesin and dynein, and transport protein complex, IFT particles. Disruption of ciliary structure or function causes multiple human disorder called ciliopathies affecting disease of diverse ciliated tissues ranging from eye, kidney, respiratory tract and brain. Recent explosion of research on the primary cilia and their involvement on animal development and disease attracts scientific interest on how extensively the function of cilia related to specific cell physiology and signaling pathway. In this review, I introduce general features of primary cilia and recent progress in understanding of the ciliary length control and signaling pathways transduced through primary cilia in vertebrates.

• 대한화장품학회지
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• 제44권1호
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• pp.73-79
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• 2018

일차 섬모(primary cilia)는 세포에서 안테나처럼 돌출되어 나온 기관인데, 외부 자극에 반응할 수 있는 각종 수용체와 채널, 신호 전달 인자들을 가지고 있다. 피부는 자외선, 온도, 습도, 중력, 장력 등 외부 환경에 반응하여 멜라닌이나 콜라겐을 만들고 피부 장벽을 형성한다. 피부에서는 일차 섬모가 없으면 헤어의 생성이나 각질의 분화가 억제된다는 보고가 있다. 또한 피부 색소 생성과 관련하여서는 일차 섬모가 sonic hedgehog-smoothened-GLI2 신호 전달에 의해 활성화되면 멜라닌 생성이 억제된다는 것이 알려져 있다. 피부가 자외선을 받으면 멜라닌 생성 호르몬의 양이 증가하고 멜라닌 생성 호르몬은 멜라닌 생성 세포 내 cAMP의 양을 증가시켜 멜라닌 생성 효소의 발현을 높인다. 이에 멜라닌 생성 호르몬과 세포 내 cAMP의 양을 증가시키는 물질을 처리하여 멜라닌 생성을 높였을 때 일차 섬모의 변화를 확인한 결과 일차 섬모가 감소하는 것을 확인하였다. 또한 기존 미백 원료인 유용성 감초 추출물(an ethanol extract of Glycyrrhiza glabra (EGG) root)과 Melasolv (3,4,5-trimethoxy cinnamate thymol ester (TCTE))가 일차 섬모의 발현을 증가시키고 멜라닌 생성 효소인 tyrosinase의 발현을 억제함을 확인할 수 있었다. 따라서 일차 섬모를 조절할 수 있다면 피부 색소 침착을 효과적으로 조절할 수 있을 것이다.

• BMB Reports
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• 제51권3호
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• pp.126-133
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• 2018

Hippo signaling plays critical roles in regulation of tissue homeostasis, organ size, and tumorigenesis by inhibiting YES-associated protein (YAP) and PDZ-binding protein TAZ through MST1/2 and LATS1/2 pathway. It is also engaged in cross-talk with various other signaling pathways, including WNT, BMPs, Notch, GPCRs, and Hedgehog to further modulate activities of YAP/TAZ. Because YAP and TAZ are transcriptional coactivators that lack DNA-binding activity, both proteins must interact with DNA-binding transcription factors to regulate target gene's expression. To activate target genes involved in cell proliferation, TEAD family members are major DNA-binding partners of YAP/TAZ. Accordingly, YAP/TAZ were originally classified as oncogenes. However, YAP might also play tumor-suppressing role. For example, YAP can bind to DNA-binding tumor suppressors including RUNXs and p73. Thus, YAP might act either as an oncogene or tumor suppressor depending on its binding partners. Here, we summarize roles of YAP depending on its DNA-binding partners and discuss context-dependent functions of YAP/TAZ.