Extra-hematopoietic immunomodulatory role of the guanine-exchange factor DOCK2

• Published in: Communications biology 2022-11, Vol.5 (1), p.1246-1246, Article 1246
• Main Authors: Scharler, Cornelia, Poupardin, Rodolphe, Ebner-Peking, Patricia, Wolf, Martin, Schreck, Christina, Brachtl, Gabriele, Cronemberger Andrade, Andre, Krisch, Linda, Daheron, Laurence, Schallmoser, Katharina, Jürchott, Karsten, Küchler, Judit, Stachelscheid, Harald, Volk, Hans-Dieter, Oostendorp, Robert A. J., Strunk, Dirk
• Format: Article
• Language: English
• Subjects: 13; 13/1; 13/51; 13/89; 38; 38/109; 38/90; 38/91; 42; 42/100; 631/250; 692/308; Biology; Biomedical and Life Sciences; Cdc42 protein; Cell culture; Cell differentiation; CRISPR; Fibroblasts; Filopodia; Gene expression; GTPase-Activating Proteins - genetics; Guanine; Guanine Nucleotide Exchange Factors - genetics; Guanine Nucleotide Exchange Factors - metabolism; Hemopoiesis; Humans; Immune response; Immunity; Immunomodulation; Life Sciences; Mesenchyme; Pluripotency; Progenitor cells; RNA, Small Interfering; Severe combined immunodeficiency; siRNA; Stem cells; Stromal cells; Transcriptomics
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-022-04078-1

Stromal cells interact with immune cells during initiation and resolution of immune responses, though the precise underlying mechanisms remain to be resolved. Lessons learned from stromal cell-based therapies indicate that environmental signals instruct their immunomodulatory action contributing to immune response control. Here, to the best of our knowledge, we show a novel function for the guanine-exchange factor DOCK2 in regulating immunosuppressive function in three human stromal cell models and by siRNA-mediated DOCK2 knockdown. To identify immune function-related stromal cell molecular signatures, we first reprogrammed mesenchymal stem/progenitor cells (MSPCs) into induced pluripotent stem cells (iPSCs) before differentiating these iPSCs in a back-loop into MSPCs. The iPSCs and immature iPS-MSPCs lacked immunosuppressive potential. Successive maturation facilitated immunomodulation, while maintaining clonogenicity, comparable to their parental MSPCs. Sequential transcriptomics and methylomics displayed time-dependent immune-related gene expression trajectories, including DOCK2, eventually resembling parental MSPCs. Severe combined immunodeficiency (SCID) patient-derived fibroblasts harboring bi-allelic DOCK2 mutations showed significantly reduced immunomodulatory capacity compared to non-mutated fibroblasts. Conditional DOCK2 siRNA knockdown in iPS-MSPCs and fibroblasts also immediately reduced immunomodulatory capacity. Conclusively, CRISPR/Cas9-mediated DOCK2 knockout in iPS-MSPCs also resulted in significantly reduced immunomodulation, reduced CDC42 Rho family GTPase activation and blunted filopodia formation. These data identify G protein signaling as key element devising stromal cell immunomodulation. The guanine exchange factor DOCK2 regulates the development of immunomodulatory function in human stromal cells (mesenchymal stem/progenitor cells (MSPC) and fibroblasts), as demonstrated in three models.