Human cord blood derived CD14 cell therapy provides neuroprotection in aquired brain injury

Abstract

Our lab is developing cord blood (CB)-derived cell therapies for neuronal damage resulting from hypoxic-ischemic [HI] insult. We are using mouse brain slice cultures subjected to oxygen-glucose deprivation [OGD] to study how CB cells mediate neuroprotection. We previously reported that CD14+ cells account for most of the neuroprotective activity of CB cells in this model. We used immunohistochemistry to further detail the mechanisms of this neuroprotection. Brain slice cultures established from C57BL/6J mice were subjected to 1h OGD on day 9 treated with cell populations or medium immediately after normal conditions were restored. CB CD14+ and CD14+ depleted cells were immunomagnetically prepared from CB mononuclear cells within 48h of collection. Human adult peripheral blood (PB) CD14+ populations were also tested. After 72h, slice cultures were fixed and stained with antibodies to detect astrocytes (GFAP), neurons (NeuN), oligodendrocytes (olig2), and microglia (Iba1). Glial and neuronal cells were enumerated in contiguous images of the periventricular regions using fluorescence confocal microscopy. We also characterized the effects of cell treatment on primary human astrocytes subjected to OGD stress in a microfluidics chamber. In both culture systems treatment with CB-CD14+ cells resulted in an increase in NeuN+ neurons and a decrease in the number of activated GFAP+ astrocytes following OGD shock. Cultures treated with CB-CD14+ had 2-fold more surviving neurons than those not treated. CD14 depleted cells did not protect cultures. We did not detect changes in microglia or oligodendrocytes following cell treatment. We conclude that CB CD14+ cells demonstrate a greater neuroprotective and anti-neuroinflammatory effect than PB CD14+ cells. CB CD14+ cells could mediate neuroprotection either directly on neurons or indirectly through modulation of astrocyte activation. We confirm the therapeutic potential of CB CD14+ cells in the setting of acquired HI.