Differentiation of microglia-like cells from mice hematopoietic stem cells in peripheral blood for therapeutic strategy against Alzheimer's disease

[Speaker] Eriko Kuroda:1
[Co-author] Kazuyuki Takata:1, Syohei Kawanishi:1, Yuki Toda:1, Eishi Ashihara:1
1:Clinical and Translational Physiology, Kyoto Pharmaceutical University, Japan

[Background] Alzheimer's disease (AD) is a progressive neurodegenerative disease. Amyloid-β (Aβ) accumulation in brains is thought to be a cause of AD, it is called "amyloid hypothesis". Microglia is the immune cells in brains and possess the ability of Aβ phagocytosis. However, it has been reported that microglial dysfunctions may be induced in aged brains and AD. We have hypothesized that the replacement of aged and dysregulated microglia to healthy one in AD brain is a promising therapeutic strategy against AD. However, preparing human primary microglia is ethically and technically difficult. In this study, we examined the differentiation potentials of hematopoietic stem cells (HSCs) in peripheral blood for the replacement of microglia in mice.
[Methods] C57BL/6 mice were intraperitoneally injected with granulocyte colony-stimulating factor (G-CSF) and subsequently CXCR4 antagonist (AMD3100) to mobilize HSCs into peripheral blood. Peripheral blood was collected and HSCs were enriched as lineage-negative/c-kit-positive population using magnetic activated cell sorting. HSCs were then treated with macrophage colony-stimulating factor (M-CSF) to terminally differentiate the microglia-like cells (differentiated cells). We further examined the phagocytic ability of the differentiated cells by immunocytochemistry.
[Results] Treatment with G-CSF and CXCR4 antagonist increased the yield of HSCs in peripheral blood. After the terminal differentiation with M-CSF, the HSC-derived differentiated cells expressed microglia markers such as ionized calcium binding adapter molecule 1 (Iba-1), CD11b, F4/80, triggering receptor expressed on myeloid cells 2 (TREM2). Compared with primary cultured microglia and the HSC-derived differentiated cells, both types of cells showed the phagocytic ability of Aβ. Importantly, differentiated cells from aged mice HSCs also acquired substantial ability of Aβ phagocytosis.
[Conclusions] Studies here showed that HSCs can be collected from peripheral blood, and G-CSF and CXCR4 antagonist treatment increases the number of HSCs in peripheral blood. The collected HSCs can be differentiated to the Aβ phagocytic microglia-like cells by the treatment with M-CSF. Thus, we propose HSCs from peripheral blood as a promising cell source for the low-invasive and safer cell therapy for AD.
Advanced Search