Potential role of myeloid-derived suppressor cells in transition from reaction to repair phase of bone healing process

Abstract

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells with immunosuppressive functions; these cells play a key role in infection, immunization, chronic inflammation, and cancer. Recent studies have reported that immunosuppression plays an important role in the healing process of tissues and that Treg play an important role in fracture healing. MDSCs suppress active T cell proliferation and reduce the severity of arthritis in mice and humans. Together, these findings suggest that MDSCs play a role in bone biotransformation. In the present study, we examined the role of MDSCs in the bone healing process by creating a bone injury at the tibial epiphysis in mice. MDSCs were identified by CD11b and GR1 immunohistochemistry and their role in new bone formation was observed by detection of Runx2 and osteocalcin expression. Significant numbers of MDSCs were observed in transitional areas from the reactionary to repair stages. Interestingly, MDSCs exhibited Runx2 and osteocalcin expression in the transitional area but not in the reactionary area. And at the same area, cllagene-1 and ALP expression level increased in osteoblast progenitor cells. These data is suggesting that MDSCs emerge to suppress inflammation and support new bone formation. Here, we report, for the first time (to our knowledge), the role of MDSCs in the initiation of bone formation. MDSC appeared at the transition from inflammation to bone making and regulates bone healing by suppressing inflammation.

Enzyme‐Cleaved Bone Marrow Transplantation Improves the Engraftment of Bone Marrow Mesenchymal Stem Cells

“…(38) Later, bone marrow cells from GFP transgenic mice were collected and transplanted to the recipient mice and evaluated bone marrow-derived cells. (11,14,43) Here, we reported the modified bone marrow transplantation technique, c-BMT, which is time-efficient. Our method is technically simple and reliable to engraft the bone marrow stem cells to the recipient mice.…”

Analysis of Zinc and Stromal Immunity in Disuse Osteoporosis: Mendelian Randomization and Transcriptomic Analysis

“…Th17/Treg cells can also induce inflammatory bone metabolic diseases. IL‐17F promotes osteogenesis, including proliferation, differentiation, and mineralization activities, by upregulating BMP‐2 , Runx2 , and Osterix expression and downregulating Noggin expression 60–62 …”

“…IL-17F promotes osteogenesis, including proliferation, differentiation, and mineralization activities, by upregulating BMP-2, Runx2, and Osterix expression and downregulating Noggin expression. [60][61][62] The SLC39A family of metal transporters was identified through homologies with ZIP proteins. ZIP14 was the encoding protein of SLC39A14.…”

Early monocyte response following local ablation in hepatocellular carcinoma

“…However, given that virtually all treated patients had a good response to ablation (18/21), defined as no recurrence of the disease within 6 months after treatment, we conclude that the mMDSC signature in the peripheral blood that we observed at the given time point is treatment- rather than response-related. Immunosuppression is a critical part during wound healing ( 45 ), and the recruitment of mMDSCs following ablative therapy may indicate the healing process. To delineate the role of mMDSC following local ablation, more mechanistic studies, including animal models of local ablation, would be needed.…”