비타민 D가 SH-SY5Y 세포와 Ldlr⁻/⁻ 마우스에서 신경퇴행성 질환 관련 위험요인에 미치는 영향 = Effects of Vitamin D on Neurodegeneration-Related Risk Factors in SH-SY5Y Cells and an Atherosclerosis Mouse Model

다국어 초록 (Multilingual Abstract)

Neurodegenerative diseases are characterized by progressive neuronal dysfunction driven by dysregulated cellular stress responses, chronic inflammation, and impaired metabolic homeostasis. Increasing evidence suggests that vitamin D plays an important role in the central nervous system by regulating calcium balance, inflammatory signaling, and mitochondrial function; however, its specific effects on neuronal stress responses under pathological conditions remain incompletely understood. Therefore, this study aimed to investigate whether vitamin D modulates endoplasmic reticulum (ER) stress, inflammatory signaling, amyloid-related pathways, and mitochondrial bioenergetics in SH-SY5Y neuroblastoma cells and in an atherosclerosis-induced metabolic stress mouse model.
To evaluate the effects of vitamin D on ER stress and inflammation, SH-SY5Y cells were treated with thapsigargin (Tg) or lipopolysaccharide (LPS), respectively. Cells were pretreated with vitamin D prior to Tg or LPS stimulation, and the expression of ER stress markers, inflammatory mediators, amyloid-related genes, antioxidant factors, and mitochondrial metabolism–related genes was analyzed by RT-qPCR. Mitochondrial respiration was assessed using a Seahorse XF analyzer. For in vivo experiments, LDLr⁻/⁻ mice were fed a Western diet supplemented with either normal or high levels of vitamin D, and gene expression profiles in the hippocampus and prefrontal cortex, along with histological changes in neuronal and glial morphology, were examined.
Tg treatment markedly increased ER stress markers, consistent with activation of the IRE1–XBP1 pathway. Vitamin D pretreatment selectively reduced Tg-induced sXBP1 expression, whereas ATF4, ATF6, GRP78, and EDEM1 levels remained unchanged, indicating partial modulation of the unfolded protein response. Tg stimulation also elevated NRF2 expression as a compensatory antioxidant response, and vitamin D further enhanced NRF2 levels. Importantly, Tg substantially reduced basal, ATP-linked, and maximal mitochondrial respiration, all of which were significantly restored by vitamin D pretreatment, indicating preservation of mitochondrial respiratory function under ER stress conditions.
In the LPS-induced inflammatory model, MCP-1 and IκBα expression levels were significantly increased, while vitamin D pretreatment effectively suppressed both markers, demonstrating anti-inflammatory effects through modulation of NF-κB signaling. Although LPS did not alter amyloid-related gene expression, vitamin D markedly increased basal, ATP-linked, and maximal respiration both in the presence and absence of inflammatory stimulation, suggesting enhanced neuronal bioenergetic capacity regardless of inflammatory status. Among mitochondrial biogenesis–related genes, PGC1β expression was significantly reduced under LPS-induced inflammatory conditions following vitamin D treatment, whereas other genes exhibited minimal changes, indicating that improved mitochondrial respiration occurred without transcriptional upregulation of biogenesis-related pathways.
In LDLr⁻/⁻ mice, Western diet feeding increased body weight, caloric intake, and serum lipid levels, confirming successful induction of atherosclerosis-related metabolic stress, while vitamin D supplementation did not significantly affect circulating lipid parameters. In the hippocampus, Atf4 expression was increased by metabolic stress, whereas App expression was reduced in the vitamin D–supplemented atherosclerosis group, while inflammatory and ER stress markers showed limited alterations. In the prefrontal cortex, Bace1 expression was reduced in the vitamin D–supplemented atherosclerosis group, suggesting region-specific modulation of amyloid-related pathways. Furthermore, histological analysis revealed reduced glia-like cell counts in the hippocampal CA3 region following vitamin D supplementation, implying attenuation of glial reactivity under chronic metabolic stress.
Collectively, these findings indicate that vitamin D partially modulates ER stress and inflammatory signaling while consistently enhancing mitochondrial respiratory function in neuronal cells. Although its effects on amyloid-related gene expression were limited, vitamin D supplementation reduced glial activation and exerted subtle, region-dependent molecular effects in an atherosclerosis mouse model. These results suggest that vitamin D may support neuronal resilience under cellular stress conditions, and further studies using models that more robustly induce neuroinflammation or ER stress are warranted to further elucidate the role of vitamin D in neurodegeneration-related pathologies.

목차 (Table of Contents)

• Ⅰ. 서론 1
• Ⅱ. 문헌고찰 5
• 2. 1. 신경퇴행성 질환의 병태생리 5
• 2. 1. 1. 신경퇴행성 질환 별 병태생리 5
• 2. 2. 신경세포 손상과 소포체 스트레스 (Endoplasmic Reticulum Stress, ER stress) 7
• 2. 2. 1. 신경퇴행성 질환에서의 소포체 스트레스 역할 8
• 2. 3. 신경염증 반응과 관련 기전 (NF-κB 신호 경로와 산화적 스트레스) 10
• 2. 4. 대사성 스트레스와 신경퇴행성 질환 13
• 2. 4. 1. 고콜레스테롤혈증과 신경염증의 임상적 연관성 13
• 2. 4. 2. 대사성 스트레스와 소포체 스트레스 및 염증 반응의 연계성 14
• 2. 5. 비타민 D의 생리적 기능과 신경계 작용 15
• 2. 5. 1. 비타민 D의 대사 경로 15
• 2. 5. 2. 비타민 D의 항염 및 소포체 스트레스 완화 효과 16
• 2. 5. 3. 신경세포에서의 비타민 D 작용 16
• 2. 6. 비타민 D와 신경퇴행성 질환의 연관성 17
• 2 .6. 1. 비타민 D 결핍과 인지기능 저하 17
• 2. 6. 2. 비타민 D 보충의 신경보호 효과 18
• Ⅲ. 연구 재료 및 방법 20
• 3. 1. 실험 재료 및 방법 20
• 3. 2. SH-SY5Y 세포 배양 및 실험 물질 처리 21
• 3. 3. 실시간 세포 대사 분석 24
• 3. 4. 실험동물 및 실험식이 27
• 3. 5. 희생 및 시료 수집 29
• 3. 6. 혈청 지질 농도 측정 29
• 3. 7. H&E 및 Nissl 염색 30
• 3. 8. RNA 추출, cDNA 합성 및 RT-qPCR 32
• 3. 9. 통계 분석 33
• Ⅳ. 결과 및 고찰 37
• 4. 1. 소포체 스트레스 유도 환경에서 비타민 D가 UPR 신호기전 및 아밀로이드 관련 유전자 발현에 미치는 영향 37
• 4. 2. 소포체 스트레스 유도 환경에서 비타민 D가 신경영양·항산화 인자 및 VDR 발현에 미치는 영향 42
• 4. 3. 소포체 스트레스 유도 환경에서 비타민 D가 미토콘드리아 호흡 및 생합성·대사 관련 유전자 발현에 미치는 영향 46
• 4. 4. 염증유도 환경에서 비타민 D가 UPR 신호기전 ·염증 및 아밀로이드 관련 유전자 발현에 미치는 영향 49
• 4. 5. 염증 유도 및 비염증 환경에서 비타민 D가 실시간 세포 에너지 대사 및 미토콘드리아 호흡 관련 지표의 발현에 미치는 영향 54
• 4. 6. 죽상동맥경화 마우스 모델에서 비타민 D 보충섭취가 체중 및 혈청지질에 미치는 영향 58
• 4. 7. 죽상동맥경화 마우스 모델에서 비타민 D 보충 섭취가 해마 및 전두엽피질의 알츠하이머 관련 유전자 및 BBB 관련 인자 발현에 미치는 영향 62
• 4. 8. 죽상동맥경화 마우스 모델에서 비타민 D 보충 섭취가 해마 및 전두엽피질의 알츠하이머 관련 유전자 및 BBB 관련 인자 발현에 미치는 영향 66
• 4. 9. 죽상동맥경화 마우스 모델에서 비타민 D 보충 섭취가 마우스 해마 CA1/CA3 영역의 조직학적 변화와 신경아교세포 수에 미치는 영향 69
• Ⅴ. 요약 및 결론 72
• Ⅵ. 참고문헌 75
• ABSTRACT 93