RNA-Seq Analysis Reveals Different Dynamics of Differentiation of Human Dermis- and Adipose-derived Stromal Stem Cells

Background: Tissue regeneration and recovery in the adult body depends on self-renewal and differentiation of stem and progenitor cells. Mesenchymal stem cells (MSCs) that have the ability to differentiate into various cell types, have been isolated from the stromal fraction of virtually all tissues. However, little is known about the true identity of MSCs. MSC populations exhibit great tissue-, location- and patient-specific variation in gene expression and are heterogeneous in cell composition. Methodology/Principal findings: Our aim was to analyze the dynamics of differentiation of two closely related stromal cell types, adipose tissue-derived MSCs and dermal fibroblasts (FBs) along adipogenic, osteogenic and chondrogenic lineages using multiplex RNA-seq technology. We found that undifferentiated donor-matched MSCs and FBs are distinct populations that stay different upon differentiation into adipocytes, osteoblasts and chondrocytes. The changes in lineage-specific gene expression occur early in differentiation and persist over time in both MSCs and FBs. Further, MSCs and FBs exhibit similar dynamics of adipogenic and osteogenic differentiation but different dynamics of chondrogenic differentiation. Conclusion: Our findings suggest that stromal stem cells including adipose-derived MSCs and dermal FBs exploit different molecular mechanisms of differentiation to reach a common cell fate. The early mechanisms of differentiation are lineage-specific and are similar for adipogenic and osteogenic differentiation but are distinct for chondrogenic differentiation between MSCs and FBs. Overall design: A total of 91 samples were analyzed by multiplex RNA-seq. Samples represented replicates from two patients, two cell types and three differentiation protocols, as indicated by the sample annotation. 5 barcodes were unused, but the corresponding FASTQ files are included for completeness.

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Jääger K, Islam S, Zajac P, Linnarsson S, Neuman T