3rd Department of Internal Medicine, Klinikum Rechts der Isar der Technischen Universität München, 81675 Munich, Germany.
3rd Department of Internal Medicine, Klinikum Rechts der Isar der Technischen Universität München, 81675 Munich, Germany; Helmholtz Zentrum München, Institute of Bioinformatics and Systems Biology, 85764 Neuherberg, Germany.
Stem Cell Reports. 2015 Nov 10;5(5):702-715. doi: 10.1016/j.stemcr.2015.09.018. Epub 2015 Oct 29.
Hematopoietic stem cells (HSCs) are preserved in co-cultures with UG26-1B6 stromal cells or their conditioned medium. We performed a genome-wide study of gene expression changes of UG26-1B6 stromal cells in contact with Lineage⁻ SCA-1⁺ KIT⁺ (LSK) cells. This analysis identified connective tissue growth factor (CTGF) to be upregulated in response to LSK cells. We found that co-culture of HSCs on CTGF knockdown stroma (shCtgf) shows impaired engraftment and long-term quality. Further experiments demonstrated that CD34⁻ CD48⁻ CD150⁺ LSK (CD34⁻ SLAM) cell numbers from shCtgf co-cultures increase in G0 and senescence and show delayed time to first cell division. To understand this observation, a CTGF signaling network model was assembled, which was experimentally validated. In co-culture experiments of CD34⁻ SLAM cells with shCtgf stromal cells, we found that SMAD2/3-dependent signaling was activated, with increasing p27(Kip1) expression and downregulating cyclin D1. Our data support the view that LSK cells modulate gene expression in the niche to maintain repopulating HSC activity.
造血干细胞（HSCs）在与 UG26-1B6 基质细胞或其条件培养基共培养中得以保存。我们对与 Lineage⁻ SCA-1⁺ KIT⁺（LSK）细胞接触的 UG26-1B6 基质细胞的基因表达变化进行了全基因组研究。该分析确定结缔组织生长因子（CTGF）是对 LSK 细胞的响应而上调的。我们发现，在 CTGF 敲低基质（shCtgf）上共培养 HSCs 会导致植入和长期质量受损。进一步的实验表明，shCtgf 共培养物中的 CD34⁻ CD48⁻ CD150⁺ LSK（CD34⁻ SLAM）细胞数量在 G0 和衰老时增加，并显示出第一次细胞分裂的延迟时间。为了理解这一观察结果，我们组装了一个 CTGF 信号网络模型，并进行了实验验证。在 CD34⁻ SLAM 细胞与 shCtgf 基质细胞的共培养实验中，我们发现 SMAD2/3 依赖性信号被激活，p27(Kip1)表达增加，cyclin D1 下调。我们的数据支持这样一种观点，即 LSK 细胞调节龛内的基因表达以维持造血干细胞的再生活性。
