Protection of neutrophils by bone marrow mesenchymal stromal cells is enhanced by tumor-associated inflammatory cytokines

• Published in: Frontiers in immunology Vol. 15; p. 1361596
• Main Authors: Liang, Yingqi, Lou, Xiulan, Xu, Yazhang, Zheng, Zhiyuan
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 16.04.2024
• Subjects: Animals; Apoptosis; Cell Line, Tumor; Coculture Techniques; Cytokines - metabolism; G-CSF; Granulocyte Colony-Stimulating Factor - metabolism; Immunology; inflammation; Mesenchymal Stem Cells - immunology; Mesenchymal Stem Cells - metabolism; mesenchymal stromal/stem cells; Mice; Mice, Inbred C57BL; Neoplasms - immunology; Neoplasms - pathology; neutrophil; Neutrophils - immunology; Neutrophils - metabolism; Tumor Necrosis Factor-alpha - metabolism; tumor progression; mesenchymal stromal/stem cells; tumor progression; inflammation; G-CSF; neutrophil
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2024.1361596

Mesenchymal stromal/stem cells (MSCs), which are distributed in many tissues including bone marrow, have been reported to play a critical role in tumor development. While bone marrow, the primary site for hematopoiesis, is important for establishing the immune system, whether MSCs in the bone marrow can promote tumor growth via influencing hematopoiesis remains unclear. We observed that the numbers of MSCs and neutrophils were increased in bone marrow in tumor-bearing mice. Moreover, co-culture assay showed that MSCs strongly protected neutrophils from apoptosis and induced their maturation. G-CSF and GM-CSF have been well-documented to be associated with neutrophil formation. We found a remarkably increased level of G-CSF, but not GM-CSF, in the supernatant of MSCs and the serum of tumor-bearing mice. The G-CSF expression can be enhanced with inflammatory cytokines (IFNγ and TNFα) stimulation. Furthermore, we found that IFNγ and TNFα-treated MSCs enhanced their capability of promoting neutrophil survival and maturation. Our results indicate that MSCs display robustly protective effects on neutrophils to contribute to tumor growth in bone niches.