Profiling of serum-derived exosomal microRNAs in alzheimer’s disease and MOG antibody-associated disease

다국어 초록 (Multilingual Abstract)

Exosomes are nano-sized extracellular vesicles with excellent biocompatibility and the ability to cross the blood-brain barrier, making them promising biomarkers for central nervous system (CNS) disorders. Here, this study investigated exosomal miRNA expression patterns in relation to cognitive function across different APOE genotypes in Alzheimer’s disease (AD) and disease status in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Using small RNA sequencing and NanoString analysis, distinct miRNA signatures were identified that distinguished cognitively impaired (CI) from cognitively unimpaired (CU) individuals in the E2(+), E3E3, and E4(+) AD groups, as well as relapsing from monophasic MOGAD patients. In the E2(+) group, hsa-miR-485-3p and hsa-miR-148a-3p were significantly correlated with AD biomarkers and demonstrated good diagnostic performance. In the E3E3 group, hsa-miR-151a-3p showed correlations with p-Tau isoforms, amyloid centiloids, and neurofilament light chain (NfL), a marker of axonal damage marker, and glial fibrillary acidic protein (GFAP), a marker of astrogliosis, while also exhibiting the highest diagnostic accuracy. In the E4(+) group, hsa-miR-6515-5p correlated with several AD-related biomarkers including MMSE scores, while hsa-miR-301a-3p exhibited the best performance in distinguishing cognitive function. In MOGAD, hsa-miR-548a-5p and hsa-miR-518e-3p demonstrated strong potential for distinguishing disease status. Correlation analyses revealed that hsa-miR-644a and hsa-miR-641 were associated with disease activity in MOGAD. GO and KEGG pathway analyses in both diseases highlighted neurodevelopmental and synaptic function-related pathways. This study thoroughly examined the exosomal miRNA profiles across APOE genotypes in AD and disease status of MOGAD, emphasizing the potential of exosomal miRNAs as biomarkers for cognitive function in AD as well as disease progression in MOGAD. Although I observed several miRNA signatures across these diseases, additional validation cohorts are needed to confirm these observations. Further studies are also essential to determine whether miRNA alterations are causally involved in disease progression or represent downstream consequences of pathology.

국문 초록 (Abstract)

엑소좀은 우수한 생체 적합성과 혈뇌장벽을 통과할 수 있는 나노 크기의 세포외 소포체로, 이러한 특징들로 인해 중추신경계 질환에서의 유망한 바이오 마커로 주목받고 있다. 본 연구에서는 RNA 시퀀싱과 NanoString 분석을 통해 알츠하이머병 (AD) 환자에서 APOE 유전자형별 인지기능 상태와 MOG 항체 관련 질환 (MOGAD)에서 질병의 상태 (단발성과 재발성)에 따른 엑소좀 내 miRNA 발현 양상을 조사했다. E2(+) 군에서는 인지기능이 저하된 군 (CI)에서 감소된 hsa-miR-485-3p, hsa-miR-148a-3p가 AD 바이오 마커와 유의한 상관관계를 보였으며 진단 성능이 우수했다. E3E3 군에서는 hsa-miR-151a-3p가 인산화된 타우, 아밀로이드 센틸로이드, 신경미세섬유 경연쇄 (NfL), 신경교세포 섬유성 산성 단백질 (GFAP)과 유의한 상관관계를 보일 뿐 아니라 높은 진단 성능을 보였다. E4(+) 군에서는 hsa-miR-6515-5p가 AD 바이오 마커 및 MMSE 점수와 유의한 상관관계를 보였으며, hsa-miR-301a-3p가 우수한 진단 성능을 보였다. MOGAD 분석에서는 총 26개의 유의하게 변화한 miRNA가 발굴되었으며 hsa-miR-548a-5p와 hsa-miR-518e-3p가 우수한 진단 성능을 보였다. 상관관계 분석 결과, hsa-miR-644a-와 hsa-miR-641은 MOGAD 관련 임상 지표와 유의한 상관 관계를 보였다. 기능적 풍부도 분석 (Functional enrichment analysis) 결과 두 질환에서 변화한 miRNA들이 신경계발달 및 시냅스 기능 관련 경로와 유의하게 연관되어 있다. 본 연구는 AD에서 APOE 유전자형별로, MOGAD에서 질병의 상태에 따른 엑소좀 내 miRNA 발현 양상을 밝혀내며, AD 연구에서의 유전자형 기반 분석의 중요성과 MOGAD에서의 엑소좀 miRNA의 바이오 마커로서의 가능성을 부각시켰다. 그럼에도 불구하고 더 큰 규모의 검증 코호트에서 이러한 결과가 재현되는지 확인이 필요하며, 이렇게 변화한 miRNA들이 질병의 진행을 유도하는 원인인지 혹은 질병의 진행상황에 따른 결과물인지에 대한 후속 연구가 필요하다.

목차 (Table of Contents)

• Chapter 1. INTRODUCTION 1
• 1.1. Exosome 1
• 1.2. Alzheimer’s disease 5
• 1.3. MOG Antibody-Associated disease 12
• Chapter 2. MATERIALS & METHODS 18
• 2.1. Isolation of RNA from serum-derived small extracellular vesicles (sEVs) 18
• 2.2. Nanoparticle tracking analysis 19
• 2.3. Cryogenic Transmission Electron Microscopy (Cryo-TEM) 19
• 2.4. Western blot analysis 20
• 2.5. Small RNA Sequencing and Data Processing (Alzheimer’s Disease Samples) 21
• 2.6. NanoString Profiling of miRNAs (MOGAD Samples) 22
• 2.7. Differential Expression Analysis of miRNAs 23
• 2.8. Spearman’s rank correlation analysis 24
• 2.9. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis 24
• 2.10. Receiver Operating Characteristic (ROC) analysis 25
• Chapter 3. RESULTS 27
• 3.1. Profiling of serum-derived exosomal microRNAs in Alzheimer’s disease 27
• 3.1.1. Characterization of sEVs isolated from the serum of cognitively unimpaired and impaired individuals 27
• 3.1.2. Differential expression of miRNAs between E2(+) CI and E2(+) CU 29
• 3.1.3. Correlation between DEmiRNAs and clinical traits in the E2(+) group 36
• 3.1.4. Diagnostic potential of DEmiRNAs in the E2(+) group 42
• 3.1.5. Differential expression of miRNAs between E3E3 CI and E3E3 CU 45
• 3.1.6. Correlation between DEmiRNAs and clinical traits in the E3E3 group 55
• 3.1.7. Diagnostic potential of DEmiRNAs in the E3E3 group 63
• 3.1.8. Differential expression of miRNAs between E4(+) CI and E4(+) CU 66
• 3.1.9. Correlation between DEmiRNAs and clinical traits in the E4(+) group 76
• 3.1.10. Diagnostic potential of DEmiRNAs in the E4(+) group 85
• 3.2. Profiling of serum-derived exosomal microRNAs in MOG antibody-associated disease 88
• 3.2.1. Differential expression of miRNAs between relapsing and monophasic MOGAD patients 88
• 3.2.2. Correlation between DEmiRNAs and clinical traits in the disease status of MOGAD 98
• 3.2.3. Diagnostic potential of DEmiRNAs in the MOGAD 107
• Chapter 4. DISCUSSION 112
• Chapter 5. CONCLUSIONS 116
• REFERENCES 118
• 논문요약 131