Epigenetic Regulation and Tumor-Suppressive Role of a Liver-Specific Long Non-Coding RNA via Notch Pathway Inhibition in Hepatocellular Carcinoma
- 주제(키워드) hepatocellular carcinoma , long non-coding RNA , MASLD , fatty acid oxidation , AMPK pathway hepatic steatosis
- 주제(DDC) 570
- 발행기관 아주대학교 일반대학원
- 지도교수 정재연
- 발행년도 2026
- 학위수여년월 2026. 2
- 학위명 석사
- 학과 및 전공 일반대학원 의생명과학과
- 실제URI http://www.dcollection.net/handler/ajou/000000035776
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
In chapter 1, Long non-coding RNAs (lncRNAs) have emerged as critical regulators in the pathogenesis of hepatocellular carcinoma (HCC), yet the mechanisms governing liver-specific lncRNAs remain largely unexplored. In this study, we identified and characterized a novel liver-specific lncRNA, designated as Liver-specific Upregulated Non-coding RNA regulator (LUNAR), which plays a key tumor-suppressive role in HCC progression. Through a comprehensive analysis of stage-specific transcriptomic datasets, LUNAR was discovered to be a liver-enriched transcript whose expression is progressively diminished during hepatocarcinogenesis. Integrative validation using multiple patient cohorts, in vitro migration and invasion assays, and in vivo orthotopic xenograft models demonstrated that restoring LUNAR expression markedly inhibits metastatic behaviors without affecting proliferation. Mechanistically, this anti-metastatic function is mediated through selective suppression of the NOTCH signaling pathway, while its downregulation in tumors is driven by promoter hypermethylation leading to epigenetic silencing. Collectively, these findings define LUNAR as a liver-specific, epigenetically regulated tumor suppressor lncRNA with strong diagnostic and prognostic potential, providing new insights into HCC metastasis and offering a promising target for future therapeutic intervention. In chapter 2, this study first demonstrated that Odoribacter splanchnicus (O. splanchnicus)–conditioned media dose-dependently reduced free fatty acid– induced lipid accumulation in HepG2 and Hepa1-6 cells, indicating a direct anti-steatotic effect in vitro. Consistent with these findings, supplementation with O. splanchnicus markedly alleviated Western diet–induced hepatic steatosis, inflammation, and fibrosis in mice. Mechanistically, O. splanchnicus restored the expression of key fatty acid oxidation regulators, including PPAR- α, ACOX1, and CPT1A, supporting its role in enhancing lipid metabolic homeostasis. Together with our observation that O. splanchnicus abundance was significantly reduced in MASLD patients compared with healthy controls, these results suggest that O. splanchnicus exerts hepatoprotective and anti-steatotic effects and may represent a promising microbial therapeutic candidate for MASLD management.
more목차
Chapter 1. Epigenetic Regulation and Tumor-Suppressive Role of a Liver-Specific Long Non-Coding RNA via Notch Pathway Inhibition in Hepatocellular Carcinoma 1
Ⅰ. INTRODUCTION 2
Ⅱ. MATERIALS AND METHODS 5
1. Public Dataset Resources 5
2. Sample Collection and Clinical Definitions 6
3. RNA Isolation from Paired HCC Tissues and Cell Lines. 7
4. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) 7
5. Cell Culture and Transfection 8
6. Cell Growth and Viability 10
7. Wound-Healing Assay 10
8. Transwell Assay 11
9. Western Blotting 12
10. Mouse Orthotopic Model 13
11. Immunohistochemistry (IHC) 14
12. Quantitative Methylation-Specific Polymerase Chain Reaction (qMSP) 15
13. 5-Aza-2′-Deoxycytidine (5-Aza) Treatment 16
14. Statistical Analysis 16
Ⅲ. RESULTS 18
1. Identification of LUNAR as a liver-specific lncRNA biomarker for HCC 18
2. Functional analysis of LUNAR reveals its inhibitory role in HCC cell motility 26
3. Anti-metastatic function of LUNAR in vivo 32
4. LUNAR is epigenetically repressed by DNA hypermethylation 37
5. LUNAR selectively suppresses NOTCH signaling in HCC 43
Ⅳ. DISCUSSION 47
Chapter 2. Investigation of Gut Microbiota-Derived Beneficial Strains for the Prevention and Treatment of Metabolic Dysfunction-Associated Steatotic Liver Disease 50
Ⅰ. INTRODUCTION 51
Ⅱ. MATERIALS AND METHODS 55
1. Patients 55
2. Stool analysis for the metagenomics 55
3. 16s rRNA ribosomal analysis 57
4. Identification of differentially abundant taxa between healthy controls and MASLD in 16S rRNA microbiome data 57
5. Multivariable association analysis using MaAsLin2 58
6. Shotgun metagenomic processing and microbiome profiling 59
7. Strain preparation 60
8. Animal experiments 61
9. Pathology analysis 62
10. Serum Biochemistry Analysis 63
11. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) 64
12. Western blot 65
13. Immunohistochemistry (IHC) 66
14. Cell culture 67
15. Anti-steatosis assay 67
16. ORO staining 68
17. MTT assay 69
18. Strain-specific PCR 69
Ⅲ. RESULTS 71
1. Identification of O. splanchnicus as a MASLD-associated strain 71
2. Microbial signatures associated with MASLD identified in the 16S training cohort 78
3. Multivariable association analysis identifies clinically relevant MASLD-associated taxa in the training cohort 81
4. Independent Shotgun Validation Identifies O. splanchnicus as the Only Cross-Cohort Species Consistently Depleted in MASLD 85
5. Cross-Platform Clinical Association Reinforce O. splanchnicus as a Reproducibly MASLD-Depleted Species 89
6. In vitro validation demonstrates that O. splanchnicus–derived conditioned medium suppresses fatty-acid–induced lipid accumulation in hepatocytes 91
7. Oral administration of O.splanchnicus mitigates Western-diet– induced hepatic steatosis in vivo 95
8.O.splanchnicus Mitigates Western Diet–Induced Hepatocyte Proliferation and Inflammatory Signaling 99
9. O. splanchnicus extract attenuates Western diet–induced hepatic inflammation and fibrosis while restores bile acid and fatty acid metabolic signaling 101
10. O. splanchnicus supplementation reactivates hepatic AMPK–PPAR α signaling and restores fatty acid β-oxidation in Western diet–fed mice 105
Ⅳ. DISCUSSION 108
Ⅴ. REFERENCES 112
국문 요약 120
