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ACVR1R206H extends inflammatory responses in human induced pluripotent stem cell-derived macrophages
Koji Matsuo1, Abigail Lepinski2, Robert D Chavez1
1Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA, USA; The Institute for Human Genetics, University of California, San Francisco, CA, USA; The Program in Craniofacial Biology, University of California, San Francisco, CA, USA.
Abstract:
Macrophages play crucial roles in many human disease processes. However, obtaining large numbers of primary cells for study is often difficult. We describe 2D and 3D methods for directing human induced pluripotent stem cells (hiPSCs) into macrophages (iMACs). iMACs generated in 2D culture showed functional similarities to human primary monocyte-derived M2-like macrophages, and could be successfully polarized into a M1-like phenotype. Both M1- and M2-like iMACs showed phagocytic activity and reactivity to endogenous or exogenous stimuli. In contrast, iMACs generated by a 3D culture system showed mixed M1- and M2-like functional characteristics. 2D-iMACs from patients with fibrodysplasia ossificans progressiva (FOP), an inherited disease with progressive heterotopic ossification driven by inflammation, showed prolonged inflammatory cytokine production and higher Activin A production after M1-like polarization, resulting in dampened responses to additional LPS stimulation. These results demonstrate a simple and robust way of creating hiPSC-derived M1- and M2-like macrophage lineages, while identifying macrophages as a source of Activin A that may drive heterotopic ossification in FOP.
Insights
Researchers developed methods to create human induced pluripotent stem cell-derived macrophages (iMACs) for disease research. 2D-cultured iMACs mimic primary macrophages and offer insights into fibrodysplasia ossificans progressiva (FOP) pathogenesis.
Area of Science:
- Stem cell biology
- Immunology
- Regenerative medicine
Background:
- Macrophages are critical in human diseases, but primary cell acquisition is challenging.
- Human induced pluripotent stem cells (hiPSCs) offer a potential source for generating specific cell types.
Purpose of the Study:
- To establish robust 2D and 3D methods for differentiating hiPSCs into macrophages (iMACs).
- To characterize the functional phenotypes of iMACs and compare them to primary macrophages.
- To investigate the role of iMACs in fibrodysplasia ossificans progressiva (FOP) pathogenesis.
Main Methods:
- Directed differentiation of hiPSCs into macrophages using 2D and 3D culture systems.
- Functional assays including phagocytosis, cytokine production, and response to stimuli.
- Polarization of iMACs into M1-like and M2-like phenotypes.
- Generation and analysis of iMACs from FOP patient-derived hiPSCs.
Main Results:
- 2D-cultured iMACs exhibited M2-like functions and could be polarized to an M1-like phenotype, displaying phagocytic activity.
- 3D-cultured iMACs showed mixed M1/M2 functional characteristics.
- Patient-derived 2D-iMACs, upon M1-like polarization, showed increased Activin A production and prolonged inflammatory cytokine release, with reduced response to LPS.
- Macrophages identified as a potential source of Activin A contributing to FOP's heterotopic ossification.
Conclusions:
- A reliable method for generating hiPSC-derived M1- and M2-like macrophage lineages was established.
- 2D-iMACs provide a valuable model for studying inflammatory diseases like FOP.
- Macrophages are identified as a source of Activin A, potentially driving heterotopic ossification in FOP.
