• International Journal of Stem Cells
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• 제16권1호
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• pp.27-35
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• 2023

Background and Objectives: Spermatogonial stem cells (SSCs) are the most primitive cells in spermatogenesis and are the only adult stem cells capable of passing on the genome of a given species to the next generation. SSCs are the only adult stem cells known to exhibit high Oct4 expression and can be induced to self-reprogram into pluripotent cells depending on culture conditions. Epigenetic modulation is well known to be involved in the induction of pluripotency of somatic cells. However, epigenetic modulation in self-reprogramming of SSCs into pluripotent cells has not been studied. Methods and Results: In this study, we examined the involvement of epigenetic modulation by assessing whether selfreprogramming of SSCs is enhanced by treatment with epigenetic modulators. We found that second-generation selective class I HDAC inhibitors increased SSC reprogramming efficiency, whereas non-selective HDAC inhibitors had no effect. Conclusions: We showed that pluripotent stem cells derived from adult SSCs by treatment with small molecules with epigenetic modulator functions exhibit pluripotency in vitro and in vivo. Our results suggest that the mechanism of SSC reprogramming by epigenetic modulator can be used for important applications in epigenetic reprogramming research.

• Molecules and Cells
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• 제39권8호
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• pp.631-638
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• 2016

Glutathione peroxidase 3 (GPx3), an antioxidant enzyme, acts as a modulator of redox signaling, has immunomodulatory function, and catalyzes the detoxification of reactive oxygen species (ROS). GPx3 has been identified as a tumor suppressor in many cancers. Although hyper-methylation of the GPx3 promoter has been shown to down-regulate its expression, other mechanisms by which GPx3 expression is regulated have not been reported. The aim of this study was to further elucidate the mechanisms of GPx3 regulation. GPx3 gene analysis predicted the presence of ten glucocorticoid response elements (GREs) on the GPx3 gene. This result prompted us to investigate whether GPx3 expression is regulated by the glucocorticoid receptor (GR), which is implicated in tumor response to chemotherapy. The corticosteroid dexamethasone (Dex) was used to examine the possible relationship between GR and GPx3 expression. Dex significantly induced GPx3 expression in H1299, H1650, and H1975 cell lines, which exhibit low levels of GPx3 expression under normal conditions. The results of EMSA and ChIP-PCR suggest that GR binds directly to GRE 6 and 7, both of which are located near the GPx3 promoter. Assessment of GPx3 transcription efficiency using a luciferase reporter system showed that blocking formation of the GR-GRE complexes reduced luciferase activity by 7-8-fold. Suppression of GR expression by siRNA transfection also induced down-regulation of GPx3. These data indicate that GPx3 expression can be regulated independently via epigenetic or GR-mediated mechanisms in lung cancer cells, and suggest that GPx3 could potentiate glucocorticoid (GC)-mediated anti-infla-mmatory signaling in lung cancer cells.

• Molecules and Cells
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• 제44권3호
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• pp.146-159
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• 2021

DNA methylation, and consequent down-regulation, of tumour suppressor genes occurs in response to epigenetic stimuli during cancer development. Similarly, human oncoviruses, including human papillomavirus (HPV), up-regulate and augment DNA methyltransferase (DNMT) and histone deacetylase (HDAC) activities, thereby decreasing tumour suppressor genes (TSGs) expression. Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1), an epigenetic regulator of DNA methylation, is overexpressed in HPV-induced cervical cancers. Here, we investigated the role of UHRF1 in cervical cancer by knocking down its expression in HeLa cells using lentiviral-encoded short hairpin (sh)RNA and performing cDNA microarrays. We detected significantly elevated expression of thioredoxin-interacting protein (TXNIP), a known TSG, in UHRF1-knockdown cells, and this gene is hypermethylated in cervical cancer tissue and cell lines, as indicated by whole-genome methylation analysis. Up-regulation of UHRF1 and decreased TXNIP were further detected in cervical cancer by western blot and immunohistochemistry and confirmed by Oncomine database analysis. Using chromatin immunoprecipitation, we identified the inverted CCAAT domain-containing UHRF1-binding site in the TXNIP promoter and demonstrated UHRF1 knockdown decreases UHRF1 promoter binding and enhances TXNIP expression through demethylation of this region. TXNIP promoter CpG methylation was further confirmed in cervical cancer tissue by pyrosequencing and methylation-specific polymerase chain reaction. Critically, down-regulation of UHRF1 by siRNA or UHRF1 antagonist (thymoquinone) induces cell cycle arrest and apoptosis, and ubiquitin-specific protease 7 (USP7), which stabilises and promotes UHRF1 function, is increased by HPV viral protein E6/E7 overexpression. These results indicate HPV might induce carcinogenesis through UHRF1-mediated TXNIP promoter methylation, thus suggesting a possible link between CpG methylation and cervical cancer.

• 대한화장품학회지
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• 제47권2호
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• pp.107-121
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• 2021

백색증이나 백반증에서 관찰되는 피부 저색소침착은 유전적 요인, 후성유전적 요인 및 기타 요인에 의해 멜라닌 합성이 감소할 때 발생한다. 세포에서 멜라닌 합성을 촉진 할 수 있는 약물 후보를 확인하기 위해 141개의 세포 투과성 저분자 약물로 구성된 후성유전적 조절제 라이브러리를 스크리닝했다. B16/F10 쥐 흑색종 세포를 0.1 𝜇M에서 각 약물로 처리하고 멜라닌 합성 및 세포 생존력을 모니터링했다. 그 결과, (-)-네플라노신 A, 3-디아자네플라노신 A (DZNep) 및 DZNep 염산염이 세포 독성을 일으키지 않고 멜라닌 합성을 증가시키는 것으로 나타났다. 이 세 가지 구조적으로 관련된 약물은 세포 멜라닌 합성 및 세포 생존력에 유사한 용량 의존적 효과를 나타내었기 때문에 DZNep을 추가 실험을 위한 대표 약물로 선택하였다. DZNep는 세포내 멜라닌 함량과 티로시나제(TYR) 활성을 증가 시켰다. DZNep은 또한 mRNA와 단백질 수준에서 TYR, 티로시나제 관련 단백질 1 (TYRP1) 및 도파크롬 토토머라제 (DCT)의 발현을 유도했다. DZNep는 또한 멜라닌 합성의 주요 조절자인 소안구증 관련 전사 인자(MITF)의 mRNA와 단백질 발현을 유도했다. DZNep은 S-아데노실 호모시스테인 가수분해효소의 선택적 억제제이며 히스톤 메틸화효소를 저해하는 S-아데노실 호모시스테인의 세포내 축적을 유발하였다. 이 연구는 특정 세포 상황에서 S-아데노실 호모시스테인 가수분해효소를 표적함으로써 멜라닌 생성이 조절될 수 있음을 시사한다.