Peake Kyle, Manning John, Lewis Coral-Ann, Tran Kevin, Rossi Fabio, Krieger Charles
Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, BC , Canada.
The Biomedical Research Centre, University of British Columbia , Vancouver, BC , Canada.
Front Neurol. 2017 Mar 8;8:75. doi: 10.3389/fneur.2017.00075. eCollection 2017.
Bone marrow-derived cells (BMDCs) are capable of migrating across the blood-brain barrier (BBB) and accumulating in the central nervous system (CNS) when transplanted into recipients conditioned with whole-body irradiation or chemotherapy. We used the chemotherapeutic agents busulfan and treosulfan to condition recipient mice for transplantation with bone marrow (BM) cells isolated from donor mice ubiquitously expressing green fluorescent protein. We attempted to increase the accumulation of BMDCs in the CNS by mobilization of BMDCs using either, or both, granulocyte colony-stimulating factor (GCSF) or plerixafor (AMD3100). We also used several concentrations of busulfan. We hypothesized that higher concentrations of busulfan and BMDC mobilization would increase numbers of GFP cells in the CNS. The doses of busulfan employed (60-125 mg/kg) all resulted in high levels of sustained chimerism (>85% 1 year post-transplant) in both the blood and BM of wild-type (WT) mice and an amyotrophic lateral sclerosis (ALS) mouse model. Moreover, cells accumulated within the CNS in a dose-, time-, and disease-dependent manner. Conditioning with the hydrophilic busulfan analog treosulfan, which is unable to cross the BBB efficiently, also resulted in a high degree of BM chimerism. However, few GFP BMDCs were found within the CNS of WT or ALS mice of treosulfan-conditioned mice. Mobilization of BMDCs into the circulation using GCSF and/or AMD3100 did not lead to increased accumulation of GFP BMDCs within the CNS of WT or ALS mice. Weekly analysis of BMDC accumulation revealed that BMDCs accumulated more rapidly and to a greater extent in the CNS of ALS mice conditioned with a high dose (125 mg/kg) of busulfan compared to a lower dose (80 mg/kg). The number of GFP BMDCs in the CNS labeling with the proliferation marker Ki67 increased in parallel with BMDC accumulation within the CNS. Our results indicate that establishment of high levels of blood and BM chimerism alone is not sufficient to induce BMDC accumulation within the CNS and that CNS conditioning is a crucial requirement for BMDC accumulation to occur. Moreover, it appears that proliferation of BMDCs that infiltrate the CNS is partly responsible for cell accumulation in busulfan-conditioned ALS mice.
骨髓来源的细胞（BMDCs）能够穿越血脑屏障（BBB），并且当被移植到经全身照射或化疗预处理的受体中时，会在中枢神经系统（CNS）中积累。我们使用化疗药物白消安和苏消安对受体小鼠进行预处理，以便移植从广泛表达绿色荧光蛋白的供体小鼠中分离出的骨髓（BM）细胞。我们试图通过使用粒细胞集落刺激因子（GCSF）或普乐沙福（AMD3100）中的一种或两种来动员BMDCs，从而增加BMDCs在CNS中的积累。我们还使用了几种浓度的白消安。我们假设更高浓度的白消安和BMDCs动员将增加CNS中绿色荧光蛋白细胞的数量。所使用的白消安剂量（60 - 125mg/kg）在野生型（WT）小鼠和肌萎缩侧索硬化症（ALS）小鼠模型的血液和骨髓中均导致高水平的持续嵌合现象（移植后1年>85%）。此外，细胞以剂量、时间和疾病依赖的方式在CNS中积累。用亲水性白消安类似物苏消安进行预处理，其不能有效穿过血脑屏障，也导致了高度的骨髓嵌合现象。然而，在苏消安预处理的WT或ALS小鼠的CNS中几乎没有发现绿色荧光蛋白BMDCs。使用GCSF和/或AMD3100将BMDCs动员到循环中并没有导致WT或ALS小鼠的CNS中绿色荧光蛋白BMDCs积累增加。对BMDCs积累的每周分析表明，与低剂量（80mg/kg）相比，用高剂量（125mg/kg）白消安预处理的ALS小鼠的CNS中BMDCs积累更快且程度更大。用增殖标记物Ki67标记的CNS中绿色荧光蛋白BMDCs的数量与CNS内BMDCs的积累平行增加。我们的结果表明，仅建立高水平的血液和骨髓嵌合不足以诱导BMDCs在CNS中积累，并且CNS预处理是BMDCs积累发生的关键要求。此外，似乎浸润CNS的BMDCs的增殖部分负责白消安预处理的ALS小鼠中的细胞积累。
