IFN-γ and TNF-α Synergistically Induce Mesenchymal Stem/Stromal Cell Death Via RIPK1-Independent Necroptosis

• Published in: Blood 2023-11, Vol.142 (Supplement 1), p.5624-5624
• Main Authors: Ren, Xiang, Ge, Meili, Huo, Jiali, Huang, Jinbo, Wang, Min, Shao, Yingqi, Mi, Yingchang, Zheng, Yizhou
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2023-186067

Interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) are two vital inflammatory factors elevated in many diseases (e.g. aplastic anemia), and an inflammatory microenvironment can cause cell damage and may be involved in the pathogenesis of certain diseases. However, the precise mechanisms of cell dysfunction or impairment during the inflammatory process are not fully understood. IFN-γ alone or in combination with TNF-α have distinct effects on the immunoregulatory properties of bone marrow derived mesenchymal stem cells (MSCs), and they have been raised to be optimal prime factors to enhance the immunosuppressive capacity of MSCs engineered in vitro. Yet controversies remain with regards to the normal function maintenance of cells as they may be impaired after exposure to inflammatory factors. Here, we find that IFN-γ and TNF-α can synergistically induce cell dysfunction and death of MSCs via a RIPK1-independent manner of necroptosis. When MSCs are exposed to both IFN-γ and TNF-α at a broad range of concentrations used in previous studies for about 24 hours or more, its morphological features, biological functions, differentiation capacity and immunoregulatory properties are totally injured. First of all, IFN-γ and TNF-α synergistically induce distinct morphological changes of MSCs. When primed with both IFN-γ and TNF-α, MSCs show a gradual change from a fibroblastic-like spindle shape to an enlarged widespread morphology and the cells grow in a disordered way. And from a high power view, the cells looked like a flat spider web and the blurred cell membrane hints that these cells may have “ruptured”, but most notably, the immunofluorescence staining shows that the nuclei were intact. Secondly, MSCs are functionally impaired after exposure in regard to their capacities of proliferation and migration, which, however, are not associated with increased cell apoptosis or senescence. Furthermore, the adipocytes, osteocytes and chondrocytes differentiation capacities of MSCs are entirely impaired and the immunosuppressive efficacies of MSCs on T cells are also attenuated by the synergistic effect of IFN-γ and TNF-α, though these impaired MSCs retain normal capacity of releasing indoleamine 2,3-dioxygenase (IDO), an immunosuppressive mediator of human MSCs. Mechanistically, we initially find that the signaling of IFN-γ might be enhanced by TNF-α through increasing the abundance of its receptor IFN-γ receptor1 on the surface of MSCs, which is possible t