Physical signals provided by the extracellular matrix (ECM) are key microenvironmental parameters for the fate decision of hematopoietic stem and progenitor cells (HSPC) in bone marrow. Insights into cell-ECM interactions are critical for advancing HSC-based tissue engineering. Herein, we employed collagen hydrogels and collagen-alginate hydrogels of defined stiffness to study the behaviors of hematopoietic progenitor cells (HPCs). Three-dimensional (3D) collagen hydrogels with a stiffness of 45 Pa were found to promote HPC maintenance and colony formation of monocyte/macrophage progenitors. Using single-cell RNA sequencing (scRNA-seq), we also characterized the comprehensive transcriptional profiles of cells randomly selected from two-dimensional (2D) and 3D hydrogels. A distinct maturation trajectory from HPCs into macrophages within the 3D microenvironment was revealed by these results. 3D-derived macrophages expressed high levels of various cytokines and chemokines, such as Saa3, Cxcl2, Socs3 and Tnf. Furthermore, enhanced communication between 3D-macrophages and other hematopoietic clusters based on ligand-repair interactions was demonstrated through bioinformatic analyses. Our research underlines the regulatory role of matrix-dimensionality in HPC differentiation and therefore probably be applied to the generation of specialized macrophages.

细胞外基质 (ECM) 提供的物理信号是骨髓中造血干细胞和祖细胞 (HSPC) 命运决定的关键微环境参数。深入了解细胞-ECM 相互作用对于推进基于 HSC 的组织工程至关重要。在这里，我们使用具有确定刚度的胶原水凝胶和胶原-海藻酸盐水凝胶来研究造血祖细胞 (HPC) 的行为。发现刚度为 45 Pa 的三维 (3D) 胶原水凝胶可促进 HPC 维持和单核细胞/巨噬细胞祖细胞的集落形成。使用单细胞 RNA 测序 (scRNA-seq)，我们还表征了从二维 (2D) 和 3D 水凝胶中随机选择的细胞的综合转录谱。这些结果揭示了在 3D 微环境中从 HPC 到巨噬细胞的明显成熟轨迹。3D 衍生的巨噬细胞表达高水平的各种细胞因子和趋化因子，例如Saa3、Cxcl2、Socs3和Tnf。此外，通过生物信息学分析证明了基于配体修复相互作用的 3D 巨噬细胞和其他造血细胞簇之间的通信增强。我们的研究强调了基质维数在 HPC 分化中的调节作用，因此可能适用于特化巨噬细胞的产生。