국립해양박물관 소장자료 소개

제아름 한국해양대학교 국제해양문제연구소 2017 해항도시문화교섭학 Vol.0 No.17

LRRK2 Kinase Activity Induces Mitochondrial Fission in Microglia via Drp1 and Modulates Neuroinflammation

호동환,제아름,손일홍,이해진,권희석,김형건,설원기 한국뇌신경과학회 2018 Experimental Neurobiology Vol.27 No.3

Leucine-rich repeat kinase 2 (LRRK2) mutations are the most common genetic cause of Parkinson’s disease (PD). LRRK2 contains a functional kinase domain and G2019S, the most prevalent LRRK2 pathogenic mutation, increases its kinase activity. LRRK2 regulates mitochondria morphology and autophagy in neurons. LPS treatment increases LRRK2 protein level and mitochondrial fission in microglia, and down-regulation of LRRK2 expression or inhibition of its kinase activity attenuates microglia activation. Here, we evaluated the direct role of LRRK2 G2019S in mitochondrial dynamics in microglia. Initial observation of microglia in G2019S transgenic mice revealed a decrease in mitochondrial area and shortage of microglial processes compared with their littermates. Next, we elucidated the molecular mechanisms of these phenotypes. Treatment of BV2 cells and primary microglia with LPS enhanced mitochondrial fission and increased Drp1, a mitochondrial fission marker, as previously reported. Importantly, both phenotypes were rescued by treatment with GSK2578215A, a LRRK2 kinase inhibitor. Finally, the protein levels of CD68, an active microglia marker, Drp1 and TNF-α were significantly higher in brain lysates of G2019S transgenic mice compared with the levels in their littermates. Taken together, our data suggest that LRRK2 could promote microglial mitochondrial alteration via Drp1 in a kinase-dependent manner, resulting in stimulation of pro-inflammatory responses. This mechanism in microglia might be a potential target to develop PD therapy since neuroinflammation by active microglia is a major symptom of PD.

Coat protein I depletion-associated Golgi fragmentation in an Alzheimer’s disease model

김미정,제아름,김효정,허양훈,권희석 한국통합생물학회 2015 Animal cells and systems Vol.19 No.1

The onset and progression of Alzheimer’s disease (AD) is closely associated with amyloid β (Aβ) peptide-inducedcytotoxicity and abnormal protein transportation caused by breakdown of endoplasmic reticulum (ER)–Golgi apparatustrafficking network. Although the fragmentation of Golgi apparatus has been reported in AD human patients and variousAD model animals, the molecular mechanisms causing the morpho-functional impairments of Golgi apparatus during ADprogression remain poorly understood. Thus, we investigated the ultrastructure of Golgi apparatus and coat protein I (COPI)expression in β-amyloid precursor protein/presenilin-1 double transgenic mouse and Aβ-stimulated BV-2 cell as an ADmodel using cryo-immunogold electron microscopy. In the neurons of the hippocampus of transgenic mouse and BV-2 cell,the cisternae of Golgi stacks were fragmented in difference with that of wild type mouse and cells. In addition, we furthershowed the COPI depletion in Golgi apparatus, which demonstrated the impairment of molecular integrities of Golgiapparatus. Taken together, our results provide insights into the Golgi apparatus-involved morphopathology of AD and wesuggest that the Golgi fragmentation is caused by the depletion of COPI affecting the intra-Golgi transport throughstimulation and accumulation of Aβ during AD development.

고압동결고정을 이용한 애기장대 줄기의 cryo-SEM 분석법

최윤정,이경환,제아름,채희수,장지훈,이은지,권희석,Choi, Yun-Joung,Lee, Kyung-Hwan,Je, A-Reum,Chae, Hee-Su,Jang, Ji-Hoon,Lee, Eun-Ji,Kweon, Hee-Seok 한국현미경학회 2012 Applied microscopy Vol.42 No.2

The scanning electron microscopy is an ideal technique for examining plant surface at high resolution. Most hydrate samples, however, must be fix and dehydrate for observation in the scanning electron microscope. Because the microscopes operate under high vacuum, most specimens, especially biological samples, cannot withstand water removal by the vacuum system without morphological distortion. Cryo-techniques can observe in their original morphology and structure without various artifacts from conventional sample preparation. Rapid cooling is the method of choice for preparing plant samples for scanning electron microscopy in a defined physiological state. As one of cryo-technique, high-pressure freezing allows for fixation of native non-pretreated samples up to $200{\mu}M$ thick and 2 mm wide with minimal or no ice crystal damage for the freezing procedure. In this study, we could design to optimize structural preservation and imaging by comparing cryo-SEM and convention SEM preparation, and observe a fine, well preserved Arabidopsis stem's inner ultrastructure using HPF and cryo-SEM. These results would suggest a useful method of cryo-preparation and cryo-SEM for plant tissues, especially intratubule and vacuole rich structure.

연성 이종 재료 시료의 상온 절편 제작법

채희수,권희석,제아름,이석훈,김진규,Chae, Hee-Su,Kweon, Hee-Seok,Je, A-Reum,Lee, Seok-Hoon,Kim, Jin-Gyu 한국현미경학회 2012 Applied microscopy Vol.42 No.1

For TEM study of biological samples or polymers that are contained in organic structure, it is often required that the sample is prepared by using ultramicrotome and stained with proper agents to increase the contrast of organic structure. In this study, we investigated an efficient TEM sample preparation method for ductile heterogeneity material by using ultramicrotomy. Cryo-ultramicrotomy is a suitable method that is capable of rendering sample hardness for various ductile materials. However, it has several factors to consider, such as experimental cost, working time and finding the optimal staining conditions. To satisfy these considerations, we prepared TEM sample by using ultramicrotome without cryofunction, and secured the sample hardness by applying the staining process prior to ultrathin sectioning. The cross-linked polyethylene structure in the sample was stained with the 2% $RuO_4$ solution in a sealed test tube for 24 hours at $4^{\circ}C$. After the sample staining, ultrathin sections of sample were prepared using ultramicrotome. As a result, it was revealed that the difficulties associated with staining of ultrathin sections prepared by low-temperature conditions were improved. In addition, appropriate staining depth of sample could be selected for sectioning process. The quality of TEM sample obtained by using this method was better than that of cryo-ultramicroscopy. Finally, it is expected that our method could be effectively applied in TEM sample preparation for a variety of nano-bio convergence materials.

생물시료의 3D Tomogram 정밀도 개선을 위한 Band-pass Filtering 활용

류근용,김미정,최기주,제아름,김수진,이철현,정현석,박종원,권희석,Ryu, Keun-Yong,Kim, Mi-Jeong,Choi, Ki-Joo,Je, A-Reum,Kim, Soo-Jin,Lee, Chul-hyun,Jung, Hyun-Suk,Park, Jong-Won,Kweon, Hee-Seok 한국현미경학회 2012 Applied microscopy Vol.42 No.2

Electron tomography (ET) of biological specimens is performed from a series of images obtained over a range of tilt angles in a transmission electron microscope. When using the high voltage electron microscope (HVEM), various noises appear in EM images acquired from thick sections by high voltage electron beam. In order to obtain an adequate result in electron tomograms that allow visualization of rather complex and mega-cellular structure such as brain tissue, it is necessary to remove the noise in each original tilt images of thick section. Using band-pass filtering of original tilt images, the filtered images are obtained and used to assemble a reconstructed tomogram. The qualified 3D tomogram from filtered images results in a considerable reduction of the noises compared to conventional tomogram. In conclusion, this study suggests that band-pass filtering is effective to improve the brightness and intensity of HVEM produced tomograms acquired from micron-thick sections of biological specimens.

3D Tomogram 향상을 위한 필터링 기술의 활용

류근용 ( Keun Yong Ryu ),조혜진 ( Hye-jin Cho ),채희수 ( Hee-su Chae ),제아름 ( A-reum Je ),정현석 ( Hyun Suk Jung ),권희석 ( Hee-seok Kweon ) 한국정보처리학회 2010 한국정보처리학회 학술대회논문집 Vol.17 No.2

본 연구는 이미지 필터링 효과를 적용한 이미지들을 3D tomogram으로 만들었을 때 어느 정도의 효과적인 복원이 가능하고 또 어떤 해상도의 필터를 사용했을 때 더 나은 결과를 얻어 낼 수 있는 지 확인하기 위해 진행하였다. 전자현미경으로 2D tilted image들을 찍는 과정에는 고전압의 사용으로 인한 다소의 오류들이 발생한다. 따라서 이러한 오류를 상쇄시키고 3D tomogram의 질적 향상을 위하여Gaussian low-pass filtering을 사용하였다. 또한 Gaussian low-pass filtering 내에서도 어떤 해상도 값의 필터링을 사용해야 더 나은 결과를 얻을 수 있는 지 확인하였다.

선택적 Filtering을 이용한 효율적 전자현미경 Electron Tomography 시스템

정원구 ( Won-goo Jung ),조혜진 ( Hye-jin Cho ),박성옥 ( Seong Oak Park ),채희수 ( Hee-su Chae ),제아름 ( A-reum Je ),이경환 ( Kyoung Hwan Lee ),정현석 ( Hyun Suk Jung ),권희석 ( Hee-seok Kweon ) 한국정보처리학회 2009 한국정보처리학회 학술대회논문집 Vol.16 No.2

Electron tomography를 이용한 3차원적 영상 시각화는 electron microscopy를 통해 하나의 실험 대상으로부터 연속된 이미지를 생산함으로써 이루어진다. 이미지 데이터 내부에는 대용량의 정보값을 포함하고 있어 3차원 구조물로의 변환이 가능하다. electron tomography 작업 과정 중 고해상도 원본 이미지에 pattern recognition 알고리즘이 적용된 필터링을 적용하면 실험에 필요한 데이터의 정보 손실을 최소화한 상태에서 electron tomography 시스템의 효율성을 높일 수 있다. 또한 tomographic reconstruction이 진행되는 각 단계에 hanning windowing을 적용하면 불필요한 정보 값이나 노이즈 등을 효과적으로 거할 수 있다. 윤곽선 데이터의 효과적 활용을 위하여 sobel 필터 처리를 할 경우 관찰하고자 하는 상의 윤곽선 특징을 뚜렷하게 시각화 할 수 있었다. 본 연구를 통하여 데이터의 시각화 과정에서 실험의 신뢰성 확보를 위해 원본 이미지를 기반으로 하는 tomogram과 필터링을 적용한 tomogram을 비교하여 최종 결과물의 정확도를 높이고, electron tomography를 통한 결과물의 질적 향상을 유도할 수 있음을 확인하였다.