Hspa9 Haploinsufficiency Alters Ciliogenesis and Leads to Impaired Cerebellar Development : Hspa9 발현 저하는 섬모 형성 이상을 일으켜 소뇌 발달의 결함을 초래한다

다국어 초록 (Multilingual Abstract)

Heat shock protein family A member 9 (HSPA9) is a mitochondrial chaperone essential for protein folding and the regulation of mitochondrial membrane potential. Although its mitochondrial functions are well established, its developmental roles have remained unclear. In this study, a role of HSPA9 in regulating primary cilium architecture and cilium-dependent signaling during cerebellar development is identified. In Hspa9 heterozygous mice, Purkinje cells display abnormally elongated and persistent primary cilia, accompanied by disturbances in Sonic hedgehog and Wnt pathways. These changes disrupt oligodendrocyte lineage progression, ultimately producing hypermyelination and motor deficits. Loss of Hspa9 also causes mild mitochondrial dysfunction. Under these conditions, alterations in ciliary dynamics, mitochondrial stress, and impaired cell cycle–cilium coupling are observed. Collectively, these findings position HSPA9 as a critical regulator linking mitochondrial integrity with primary cilium homeostasis, providing mechanistic insight into the pathogenesis of cerebellar hypoplasia and myelination-related neurodevelopmental disorders.

목차 (Table of Contents)

• I. Introduction 1
• II. Materials and Methods 10
• Ⅱ-1. Animals 10
• Ⅱ-2. Measurement of Growth factor 10
• Ⅱ-3. Tissue Processing 11
• Ⅱ-4. Histological analysis 12
• Ⅱ-5. Primary cilia staining and confocal microscopy 13
• Ⅱ-6. Myelination analysis 13
• Ⅱ-7. Western blot analysis 14
• Ⅱ-8. Behavior tests 15
• Ⅱ-9. Isolation of mouse embryonic fibroblasts (MEFs) 18
• Ⅱ-10. Statistical analysis 19
• III. Results 22
• Ⅲ-1. Ciliopathy-like phenotypes in Hspa9+/− mice 22
• Ⅲ-2. Delayed embryonic abnormality does not lead to postnatal growth impairment in Hspa9+/− mice 27
• Ⅲ-3. Hspa9+/− mice exhibit cerebellar malformation and abnormal neuronal organization 32
• Ⅲ-4. Depletion of Hspa9 influences primary ciliogenesis in cerebellar PCs 41
• Ⅲ-5. Hedgehog reduction induces p27-dependent G1/S brake in Hspa9+/− mice 47
• Ⅲ-6. Elongation of primary cilia alters the OL lineage in Hspa9+/− mice 52
• Ⅲ-7. Downregulated Hspa9 causes motor incoordination and gait ataxia 58
• Ⅲ-8. Hedgehog signaling alters cell cycle control in MEFs 62
• Ⅲ-9. Altered mitochondrial dynamics in Hspa9+/− MEFs 67
• IV. Discussion 71
• V. References 79
• Korean abstract 85