• BMB Reports
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• 제53권5호
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• pp.284-289
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• 2020

Tamoxifen, a nonsteroidal estrogen receptor (ER) antagonist, is used routinely as a chemotherapeutic agent for ER-positive breast cancer. However, it is also causes side effects, including retinotoxicity. The retinal pigment epithelium (RPE) has been recognized as the primary target of tamoxifen-induced retinotoxicity. The RPE plays an essential physiological role in the normal functioning of the retina. Nonetheless, potential therapeutic agents to prevent tamoxifen-induced retinotoxicity in breast cancer patients have not been investigated. Here, we evaluated the action mechanisms of sulfasalazine against tamoxifen-induced RPE cell death. Tamoxifen induced reactive oxygen species (ROS)-mediated autophagic cell death and caspase-1-mediated pyroptosis in RPE cells. However, sulfasalazine reduced tamoxifen-induced total ROS and ROS-mediated autophagic RPE cell death. Also, mRNA levels of tamoxifen-induced pyroptosis-related genes, IL-1β, NLRP3, and procaspase-1, also decreased in the presence of sulfasalazine in RPE cells. Additionally, the mRNA levels of tamoxifen-induced AMD-related genes, such as complement factor I (CFI), complement factor H (CFH), apolipoprotein E (APOE), apolipoprotein J (APOJ), toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4), were downregulated in RPE cells. Together, these data provide novel insight into the therapeutic effects of sulfasalazine against tamoxifen-induced RPE cell death.

• 생명과학회지
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• 제21권1호
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• pp.9-14
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• 2011

심박수(heart rate) 및 산소 소비량(oxygen consumption) 등의 생리학적 변수는 운동자각도(RPE)와 밀접한 관련이 있으며, RPE의 남녀차이에 의한 예측 운동강도의 정확성은 아직 밝혀지지 않고 있고, 본 연구는 남녀 대학생의 심장 혈관 및 신진대사의 반응을 평가하고 남녀의 차이를 밝히는 데 있다. 남자대학생($25.1{\pm}1.56$ yr)과 여자대학생($25.0{\pm}4.12$ yr) 각각 10명이 본 연구에 자발적으로 참여를 하였고, 본 연구를 위하여 설정된RPE는 Borg의 15 범주에서 결정을 하였으며, 점증적 운동부하(graded exercise testing)는 Bruce Treadmill Protocol을 이용하였다. 남녀의 평균 slope (p=0.501)와 RPE의 plotting rates와 최대산소섭취율(% $VO_2$max)은 유의한 차이가 나타나지 않았다. 각자의 상대적 최대산소섭취량은 남학생의 경우52.36${\pm}$7.35 ml/kg/min, 여학생은 41.44${\pm}$6.71 ml/kg/min로 나타나 두 그룹간에 유의하게 큰 차이가 있었으며, 절대적 최대산소섭취량은 남학생은 4.05${\pm}$0.36 l/min, 여학생은 2.53${\pm}$0.39 l/min로 나타나 두 그룹간에 큰 차이가 나타냈다. 남학생과 여학생간의 slope, y-intercept, SEE는 통계적으로 유의한 차이는 없었다. 본 연구에서 운동강도에 따른 남학생과 여학생의 RPE 의 차이는 유의하게 나타나지 않았다. 이상의 결과로 보아 RPE는 운동중 산소섭취량에 대한 운동강도의 예측에 남녀별 차이가 없어 유효한 예측인자라고 사료된다.

• Clinical and Experimental Reproductive Medicine
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• 제38권4호
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• pp.216-221
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• 2011

Objective: To differentiate the human embryonic stem cells (hESCs) into the retinal pigment epithelium (RPE) in the defined culture condition and determine its therapeutic potential for the treatment of retinal degenerative diseases. Methods: The embryoid bodies were formed from hESCs and attached on the matrigel coated culture dishes. The neural structures consisting neural precursors were selected and expanded to form rosette structures. The mechanically isolated neural rosettes were differentiated into pigmented cells in the media comprised of N2 and B27. Expression profiles of markers related to RPE development were analyzed by reverse transcription-polymerase chain reaction and immunostaining. Dissociated putative RPE cells ($10^5$ cells/5 ${\mu}L$) were transplanted into the subretinal space of rat retinal degeneration model induced by intravenous sodium iodate injection. Animals were sacrificed at 1, 2, and 4 weeks after transplantation, and immnohistochemistry study was performed to verify the survival of the transplanted cells. Results: The putative RPE cells derived from hESC showed characteristics of the human RPE cells morphologically and expressed molecular markers and associated with RPE fate. Grafted RPE cells were found to survive in the subretinal space up to 4 weeks after transplantation, and the expression of RPE markers was confirmed with immunohistochemistry. Conclusion: Transplanted RPE cells derived from hESC in the defined culture condition successfully survived and migrated within subretinal space of rat retinal degeneration model. These results support the feasibility of the hESC derived RPE cells for cell-based therapies for retinal degenerative disease.

• 폴리머
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• 제38권3호
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• pp.364-370
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• 2014

망막색소상피(RPE)는 건강한 망막을 유지하는데 중요한 역할을 하고 RPE의 퇴화는 많은 망막질병을 유발한다. RPE 이식은 최근 망막 퇴화에 대한 가능성 있는 치료법으로 제시되고 있다. RPE 세포를 안전하게 이식하기 위해서는 지지체가 필요하므로 독특한 기계적 성질과 생체적합성을 갖는 실크를 사용하여 필름을 제조하였다. 실크필름의 FTIR, 접촉각 및 생분해성을 측정한 후, RPE 세포를 실크필름에 파종하여 그 영향을 확인하였다. MTT 분석, SEM, 면역형광염색, RT-PCR을 통해 세포의 부착, 생존도, 형태유지, 특이적 mRNA의 발현을 분석하였다. 본 연구에서는, 실크필름에 배양한 RPE 세포의 부착, 증식 및 표현형 유지가 뛰어남을 확인함으로써 실크필름의 망막 재생을 위한 조직 공학적 지지체로의 응용 가능성을 제시했다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1995년도 제12회 음성통신 및 신호처리 워크샵 논문집 (SCAS 12권 1호)
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• pp.164-167
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• 1995

RPE 음성부호화기에서 합성 필터로 인한 구동벡터 양자화잡음의 증폭효과를 분석하고 regular pulse 시퀀스의 양자화로 인한 성능감쇄를 줄이기 위해 pyramid vector 양자화방식을 도입하였다. 제안된 방식의 성능평가는 구동시퀀스 양자화를 위해 adaptive PCM을 이용하는 GSM 표준 RPE 방식과의 객관적 및 주관적 성능비교를 통해 수행하였다.T JDSMDQLRY 결과 제안된 방식은 대략 1dB의 SNR 및 segmental SNR 값 증가를 가져왔고, 또한 비공식 청취시험결과 명료도의 증가를 느낄 수 있었다.

• 한국통신학회논문지
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• 제19권9호
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• pp.1838-1847
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• 1994

현재 북미, 유럽, 일본 등에서는 디지털 이동 통신용 음성부호화 방식의 표준을 확정하여 세부기술을 경쟁적으로 개발하고 있으나, 아직까지 우리나라는 이를 확정하지 못하고 있는 실정이다. 본 논문에서는 유럽 표준인 RPE-LTP와 북미 표준인 VSELP 알고리즘을 소스 코팅에 중점을 두어 연구, 비교 및 검토하였다. 각 음성부호화기에 대해 종합적으로 분석 및 비교한 후, 성능 개선 방안에 대하여 논의하였다. 또한, 실시간 처리에 가장 큰 영향을 미치는 연산 횟수를 계산, 비교하였다. 아울러 각 부호화기의 알고리즘을 구체화하여 한국인 음성데이타에 대하여 모의 실험을 수행하였으며, 모의 실험 평가결과로서 구간 신호대 잡음비와 5-포인트 MOS를 비교하였다. 연산횟수는 VSELP 부호기의 곱센연산횟수가 가장 많은 것으로 나타났다. 26가지 음성 데이타에 대하여 구간 신호대 잡음비는 VSELP가 RPE-LTP에 비해 큰 것으로 계산되었고, 5-포인트 MOS 실험을 실시한 결과 VSELP가 RPE-LTP에 비해 음질이 동등하거나 보다 우수한 것으로 평가되었다.

• Molecules and Cells
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• 제44권3호
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• pp.168-178
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• 2021

The retinal pigment epithelium (RPE) forms a monolayer sheet separating the retina and choroid in vertebrate eyes. The polarized nature of RPE is maintained by distributing membrane proteins differentially along apico-basal axis. We found the distributions of these proteins differ in embryonic, post-natal, and mature mouse RPE, suggesting developmental regulation of protein trafficking. Thus, we deleted tumor susceptibility gene 101 (Tsg101), a key component of endosomal sorting complexes required for transport (ESCRT), in embryonic and mature RPE to determine whether ESCRT-mediated endocytic protein trafficking correlated with the establishment and maintenance of RPE polarity. Loss of Tsg101 severely disturbed the polarity of RPE, which forms irregular aggregates exhibiting non-polarized distribution of cell adhesion proteins and activation of epidermal growth factor receptor signaling. These findings suggest that ESCRT-mediated protein trafficking is essential for the development and maintenance of RPE cell polarity.

• Journal of Chest Surgery
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• 제26권9호
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• pp.718-721
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• 1993

Reexpansion pulmonary edema[ RPE ] with hypoxemia and hypotension is a very rare complication of the treatment of lung collapse secondary to pneumothorax and pleural effusion. We experienced two cases of RPE. One is a 29 year old male with complete right pneumothorax and the other is a 20 year old female with massive right pleural effusion. Life threatening pulmonary edema was developed soon after insertion of chest tube in both. Fortunately, RPE was detected early and intensive treatment was performed. They were discharged without complication. Although RPE with hypoxemia and hypotension is rare , it is very serious and occasionally life-threatening. So, chest surgeon treating lung collapse must be aware of the possibility of RPE and make an effort to prevent the occurence of this condition.

• BMB Reports
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• 제56권2호
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• pp.84-89
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• 2023

The implications of nutrient starvation due to aging on the degeneration of the retinal pigment epithelium (RPE) is yet to be fully explored. We examined the involvement of AMPK activation in mitochondrial homeostasis and its relationship with the maintenance of a healthy mitochondrial population and epithelial characteristics of RPE cells under nutrient starvation. Nutrient starvation induced mitochondrial senescence, which led to the accumulation of reactive oxygen species (ROS) in RPE cells. As nutrient starvation persisted, RPE cells underwent pathological epithelial-mesenchymal transition (EMT) via the upregulation of TWIST1, a transcription regulator which is activated by ROS-induced NF-κB signaling. Enhanced activation of AMPK with metformin decelerated mitochondrial senescence and EMT progression through mitochondrial biogenesis, primed by activation of PGC1-α. Thus, by facilitating mitochondrial biogenesis, AMPK protects RPE cells from the loss of epithelial integrity due to the accumulation of ROS in senescent mitochondria under nutrient starvation.

• Molecules and Cells
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• 제44권8호
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• pp.613-622
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• 2021

In vertebrate eyes, the retinal pigment epithelium (RPE) provides structural and functional homeostasis to the retina. The RPE takes up retinol (ROL) to be dehydrogenated and isomerized to 11-cis-retinaldehyde (11-cis-RAL), which is a functional photopigment in mammalian photoreceptors. As excessive ROL is toxic, the RPE must also establish mechanisms to protect against ROL toxicity. Here, we found that the levels of retinol dehydrogenases (RDHs) are commonly decreased in phosphatase tensin homolog (Pten)-deficient mouse RPE, which degenerates due to elevated ROL and that can be rescued by feeding a ROL-free diet. We also identified that RDH gene expression is regulated by forkhead box O (FOXO) transcription factors, which are inactivated by hyperactive Akt in the Pten-deficient mouse RPE. Together, our findings suggest that a homeostatic pathway comprising PTEN, FOXO, and RDH can protect the RPE from ROL toxicity.