Division of Nutritional Sciences, Cornell University , Ithaca, New York.
Physiol Genomics. 2018 Oct 1;50(10):817-827. doi: 10.1152/physiolgenomics.00041.2018. Epub 2018 Jul 13.
Primary human muscle progenitor cells (hMPCs) are commonly used to understand skeletal muscle biology, including the regenerative process. Variability from unknown origin in hMPC expansion capacity occurs independently of disease, age, or sex of the donor. We sought to determine the transcript profile that distinguishes hMPC cultures with greater expansion capacity and to identify biological underpinnings of these transcriptome profile differences. Sorted (CD56+/CD29+) hMPC cultures were clustered by unbiased, K-means cluster analysis into FAST and SLOW based on growth parameters (saturation density and population doubling time). FAST had greater expansion capacity indicated by significantly reduced population doubling time (-60%) and greater saturation density (+200%), nuclei area under the curve (AUC, +250%), and confluence AUC (+120%). Additionally, FAST had fewer % dead cells AUC (-44%, P < 0.05). RNA sequencing was conducted on RNA extracted during the expansion phase. Principal component analysis distinguished FAST and SLOW based on the transcript profiles. There were 2,205 differentially expressed genes (DEgenes) between FAST and SLOW (q value ≤ 0.05); 362 DEgenes met a more stringent cut-off (q value ≤ 0.001 and 2.0 fold-change). DEgene enrichment suggested FAST (vs. SLOW) had promotion of the cell cycle, reduced apoptosis and cellular senescence, and enhanced DNA replication. Novel (RABL6, IRGM1, and AREG) and known (FOXM1, CDKN1A, Rb) genes emerged as regulators of identified functional pathways. Collectively the data suggest that variation in hMPC expansion capacity occurs independently of age and sex and is driven, in part, by intrinsic mechanisms that support the cell cycle.
原代人肌肉祖细胞（hMPC）常用于理解骨骼肌生物学，包括再生过程。hMPC 扩增能力的未知来源的变异性与供体的疾病、年龄或性别无关。我们试图确定区分具有更大扩增能力的 hMPC 培养物的转录谱，并确定这些转录组谱差异的生物学基础。根据生长参数（饱和密度和倍增时间），通过无偏的 K 均值聚类分析对（CD56+/CD29+）hMPC 培养物进行分类，分为 FAST 和 SLOW。FAST 具有更大的扩增能力，表现为倍增时间显著缩短（-60%），饱和密度增加（+200%），核曲线下面积（AUC，+250%）和汇合 AUC（+120%）。此外，FAST 的死细胞 AUC 减少（-44%，P<0.05）。在扩增阶段提取 RNA 进行 RNA 测序。主成分分析根据转录谱区分 FAST 和 SLOW。FAST 和 SLOW 之间有 2205 个差异表达基因（DEgenes）（q 值≤0.05）；362 个 DEgenes 满足更严格的截止值（q 值≤0.001 和 2.0 倍变化）。DEgene 富集表明，FAST（与 SLOW 相比）促进细胞周期，减少细胞凋亡和衰老，增强 DNA 复制。新的（RABL6、IRGM1 和 AREG）和已知（FOXM1、CDKN1A 和 Rb）基因作为鉴定的功能途径的调节剂出现。总的来说，这些数据表明，hMPC 扩增能力的变化独立于年龄和性别，部分是由支持细胞周期的内在机制驱动的。
