Biology subjects

Yim, Y. S.

Publications and source records attributed to Yim, Y. S..

3 recordsLinked to original sources

bioRxiv2026

Brain-Resident CD8+ T Cells Regulate Neuronal Activity and Behavior via Interferon-Gamma

Maintaining brain homeostasis is crucial for proper function of the central nervous system and has traditionally been attributed to neuronal and glial interactions. However, recent research highlights the essential role of brain-resident immune cells in this process. Our study characterizes brain-specific CD8+ T cells and elucidates their significant contribution to brain homeostasis and behavior. We identified a distinct population of CD8+ T cells that infiltrates the brain during early development, undergoes clonal expansion, and acquires effector memory-like characteristics through interactions with microglia. Notably, the absence of these cells results in hyperactivation of neuronal activity and abnormal behaviors, due to loss of regulation of interferon-gamma (IFN-{gamma}) secreted by CD8+ T cells. Our findings demonstrate that IFN-{gamma} secreting brain-specific CD8+ T cells are crucial for maintaining the physiological level of neuronal excitability and normal behavioral patterns. This study provides novel insights into neuroimmune interactions, emphasizing the critical role of CD8+ T cells in sustaining brain function and behavior.

immunology↗

bioRxiv2025

AAV-mediated neuronal expression of FOXG1 restores oligodendrocyte maturation, myelination, and hippocampal structure in mouse models of FOXG1 Syndrome

FOXG1 syndrome is a devastating neurodevelopmental disorder caused by haploinsufficiency of the transcription factor FOXG1, leading to intellectual disability, epilepsy, and white-matter deficits. Although FOXG1 is well known for its neuronal functions, its role in glial pathology remains poorly understood. Here, we show that reducing FOXG1 selectively in neurons impairs oligodendrocyte lineage progression and myelination, establishing a critical non-cell-autonomous role for neuronal FOXG1 in glial maturation. To restore FOXG1 in neurons, we developed AAV vectors expressing human FOXG1 under neuron-specific promoters. Neonatal administration of these vectors normalized oligodendrocyte precursor cell (OPC) accumulation, enhanced myelination, and corrected hippocampal structural abnormalities in Foxg1 conditional heterozygous mice. To test therapeutic robustness under stringent conditions, we used the patient-specific W300X heterozygous model, which combines FOXG1 loss-of-function with a toxic truncated protein and represents one of the most severe FOXG1 syndrome genotypes. Remarkably, neuron-restricted AAV-FOXG1 delivery produced substantial rescue even in this high-bar model, suppressing OPC overaccumulation, restoring myelination, and progressively improving dentate gyrus morphology, with benefits persisting into adulthood. Moreover, adolescent administration remained highly effective, rescuing myelination, axonal bundle thickness, and microglial activation. These findings identify neuronal FOXG1 as a master regulator of neuron-glia interactions and establish neuron-targeted AAV-FOXG1 as a potent and clinically translatable therapeutic strategy across diverse severities of FOXG1 syndrome.

developmental biology↗

bioRxiv2023

Unveiling the enigma of Brain-resident immune cells

The immune system has been extensively studied in traditional immune hubs like the spleen and lymph nodes. However, recent advances in immunology highlight unique immune cell characteristics across anatomical compartments. In this study, we challenged conventional thinking by uncovering distinct immune cell populations within the brain parenchyma, separate from those in the blood, meninges, and choroid plexus, with unique transcriptional profiles. Brain-resident immune cells are not derived from maternal immune cells, and age-related changes, with an increase in CD8+ T cells in aged mice, are noted. Alzheimers disease (AD) alters microglias interaction with brain-resident immune cells, emphasizing immune-brain dynamics. Furthermore, we reveal dynamic immune cell interactions and essential cytokine roles in brain homeostasis, with stable cytokine expression but emerging signaling pathways in AD. In summary, this study advances our understanding of brain-resident immune cells in both normal and pathological conditions.

immunology↗