single cell RNA sequencing of hematopoietic stem cells aged in old and young niches

Purpose: Compare the transcriptome of hematopoietic stem cells (HSCs) that were aged in old and young niches Methods: barcoded GFP+ HSCs were FACS-sorted from a) three recipient mice 15 months post transplantation, and b) six serial transplantation recipient mice 5 months after the 8th transplantation, then subjected to processed using the Chromium Single-cell 3' v2 Library Kit (10× Genomics, Pleasanton, CA) following the manufacturer's instructions Results: we obtained transcriptomes of about 12k HSCs aged in young niche, and about 10k HSCs aged in old niche, with the average sequencing depth at close to 50k reads per cell Conclusions: we identified striking differences in gene expression profiles 1) between HSCs aged in young niches from mice with early aging and from mice with delayed aging, and 2) between HSCs aged in old niches and young niches when mice exhibited hematopoietic aging phenotype Overall design: single cell gene expression profiles of individual HSCs were generated from different aging onsets

研究目的：比较在老年与年轻造血干细胞巢（niche）中衰老的造血干细胞（hematopoietic stem cells, HSCs）的转录组。
实验方法：通过荧光激活细胞分选（Fluorescence-Activated Cell Sorting, FACS）从两组样本中分离带条形码标记的绿色荧光蛋白（Green Fluorescent Protein, GFP）阳性造血干细胞：a）移植后15个月的3只受体小鼠；b）第8次连续移植后5个月的6只接受过连续移植的受体小鼠。随后按照制造商说明书，使用Chromium单细胞3'端v2建库试剂盒（10× Genomics，美国加利福尼亚州普莱森顿）进行建库处理。
实验结果：共获得约12000个在年轻造血干细胞巢中衰老的造血干细胞转录组，以及约10000个在老年造血干细胞巢中衰老的造血干细胞转录组，单细胞平均测序深度接近50000条测序读段（reads）。
研究结论：本研究鉴定出两类显著的基因表达谱差异：1）来自早衰老小鼠与迟衰老小鼠的年轻造血干细胞巢中衰老的造血干细胞之间的表达差异；2）当小鼠呈现造血衰老表型时，老年与年轻造血干细胞巢中衰老的造血干细胞之间的表达差异。
实验设计：从不同衰老启动时机的个体造血干细胞中获取单细胞基因表达谱。