Age-dependent effects of metformin on human oligodendrocyte lineage cell ensheathment capacity.

Metformin restores myelination potential of aged rat A2B5+ oligodendroglia (OL) progenitor cells and may enhance recovery in children with post-radiation brain injury. Human late progenitor cells (O4+A2B5+) have superior capacity to ensheath nanofibers compared to mature OLs, with cells from pediatric sources exceeding adults. In this study we assessed effects of metformin on ensheathment capacity of human adult and pediatric progenitors and mature OLs and relate differences to transcriptional changes. A2B5+ progenitors and mature OLs, derived from surgical tissues by immune-magnetic separation, were assessed for ensheathment capacity in nanofiber plates over 2 weeks. Metformin (10µM every other day) was added to selected cultures. RNA was extracted from treated and control cultures after 2 days. For all ages, ensheathment by progenitors exceeded mature OLs. Metformin enhanced ensheathment by adult donor cells but reduced ensheathment by pediatric cells. Metformin marginally increased cell death in pediatric progenitors. Metformin induced changes in gene expression distinct for each cell type. Adult progenitors showed up-regulation of pathways involved in process outgrowth and promoting lipid biosynthesis. Pediatric progenitors showed a relatively greater proportion of down- versus up-regulated pathways, these involved cell morphology, development, and synaptic transmission. Metformin induced AMPK activation in all cell types; AMPK inhibitor BML-275 reduced functional metformin effects only with adult cells. Our results indicate age and differentiation stage related differences of human OL lineage cells in response to metformin. Clinical trials for demyelinating conditions will indicate how these differences translate in vivo. RNA was extracted from dissociated cultures of A2B5+ or A2B5- cells after two days in culture under control conditions or with addition of metformin. Bulk sequencing studies were conducted on 3 or 4 samples from each of the age groups

二甲双胍可恢复衰老大鼠A2B5阳性少突胶质细胞（oligodendroglia, OL）前体细胞的髓鞘形成潜能，并可能改善放射性脑损伤患儿的康复。人类晚期前体细胞（O4+A2B5+）与成熟少突胶质细胞相比，具备更优异的纳米纤维包裹能力，且儿科来源的细胞功能优于成人来源细胞。本研究评估了二甲双胍对成人及儿科来源的人类前体细胞与成熟少突胶质细胞的包裹能力的影响，并将功能差异与转录组变化进行关联分析。通过免疫磁分离法从手术组织中分离获取的A2B5阳性前体细胞与成熟少突胶质细胞，在纳米纤维培养板中开展为期2周的包裹能力检测。向部分培养体系中加入二甲双胍（浓度为10μM，隔日给药一次）。培养2天后，从给药组与对照组的培养体系中提取核糖核酸（ribonucleic acid, RNA）。所有年龄组的前体细胞包裹能力均优于成熟少突胶质细胞。二甲双胍可增强成人供体细胞的包裹能力，但会降低儿科来源细胞的包裹能力。二甲双胍会轻度增加儿科前体细胞的细胞死亡水平。二甲双胍诱导的基因表达变化因细胞类型而异。成人前体细胞中，与突起生长及脂质生物合成相关的信号通路呈现上调表达。儿科前体细胞中，下调通路的占比相对高于上调通路，这些通路涉及细胞形态、发育及突触传递。二甲双胍可在所有细胞类型中诱导腺苷酸活化蛋白激酶（AMP-activated protein kinase, AMPK）激活；AMPK抑制剂BML-275仅能削弱成人细胞中二甲双胍的功能效应。本研究结果表明，人类少突胶质系细胞对二甲双胍的响应存在年龄与分化阶段相关的差异。脱髓鞘疾病相关临床试验将阐明这些差异在体内的转化效应。在对照组或添加二甲双胍的培养条件下培养2天后，从A2B5阳性或A2B5阴性的解离培养物中提取核糖核酸（ribonucleic acid, RNA）。对每个年龄组的3至4份样本开展了批量测序研究。