Na-young Seo. (2023). Ultrastructural investigation of neuronal connectivity in synaptopathic mouse models. doi: 10.22677/THESIS.200000686005
Type
Thesis
Description
Synapse; Plasticity; Neural circuit; Synaptopathy; Electron microscopy
Table Of Contents
I. GENERAL INTRODUCTION 1 1.1 Synapse: the fundamental unit of the brain 1 1.2 Synaptopathy: alterations of synapses in neuropathologic conditions 5 1.3 Purposes of the study 7 II. PART 1 LRRTM3-mediated topographic specificity of hippocampal synaptic connections 12 2.1 Introduction 13 2.1.1 Hippocampal circuitry 13 2.1.2 Role of synaptic cell adhesion molecules in synaptic specificity 15 2.1.3 Leucine-rich repeat transmembrane proteins 16 2.1.4 LRRTM-relevant clinical diseases 17 2.1.5 Main questions 18 2.2 Material and Method 19 2.2.1 Animals 19 2.2.2 Preparation and transfection of cultured hippocampal neurons 19 2.2.3 Immunocytochemistry and imaging 20 2.2.4 Stereotaxic surgery 21 2.2.5 Tissue preparation using heavy metal staining 21 2.2.6 Three-dimensional reconstruction or stereology using SB-SEM 22 2.2.7 Two-dimensional analysis using TEM 23 2.2.8 Three-dimensional investigation using serial-section TEM (ssTEM) 24 2.2.9 Statistical analysis 24 2.3 Results 25 2.3.1 LRRTM3 knockdown induces decrease in dendritic PSD-95 puncta and enlargement of axonal bouton in cultured DG granule neurons 25 2.3.2 LRRTM3 selectively mediates excitatory synapse formation with the MEC in the MML of the DG 25 2.3.3 LRRTM3 loss disrupts ultrastructural organization at the DG–CA3 synapse in vivo 26 2.3.4 MF filopodial synapse with inhibitory neurons is not affected by LRRTM3 deletion 28 2.3.5 LRRTM4 in the DG does not act in the same way as LRRTM3 28 2.4 Discussion 30 III. PART 2 Selective loss of cortical synapses lacking presynaptic mitochondria in 5xFAD mouse models 53 3.1 Introduction 54 3.1.1 Alzheimer’s disease 54 3.1.2 Synaptic impairment in AD 55 3.1.3 Mitochondrial dysfunction in AD 55 3.1.4 Main question 56 3.2 Material and Method 58 3.2.1 Animals 58 3.2.2 Immunohistochemistry and analysis 58 3.2.3 Tissue preparation for heavy metal staining 59 3.2.4 Electron microscopy and analysis 59 3.2.5 Statistical analysis 61 3.3 Results 62 3.3.1 Amyloid accumulation has regional differences in the 5xFAD mouse model 62 3.3.2 Synaptic loss in the 5xFAD cortex has region-specific susceptibility 63 3.3.3 Synapses lacking presynaptic mitochondria are significantly reduced in the 5xFAD mPFC 63 3.3.4 Mitochondrial number per bouton is decreased in the 5xFAD mPFC 64 3.4 Discussion 66 IV. CONCLUSION 81 V. REFERENCES 83 Abstract in Korean 102
