2023 Fiscal Year Research-status Report
Identification of new macrophage populations promoting bone regeneration.
| Project/Area Number |
23K19731
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| Research Institution | Matsumoto Dental University |
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Principal Investigator |
何 治鋒 松本歯科大学, 総合歯科医学研究所, 助教 (10980047)
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| Project Period (FY) |
2023-08-31 – 2025-03-31
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| Keywords | macrophage / bone repair / Wnt signal |
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| Outline of Annual Research Achievements |
We identified the surface macrophage marker "A". Utilizing flow cytometry and staining with the A antibody, we were able to segregate F4/80+ Csf1r- cells into 3 distinct subpopulations: A high, A intermediate, and A low. Through comparison of cell frequencies and their responsiveness to clodronate liposome, we determined that A high F4/80+ Csf1r- cells are essential in bone repair.
We also identified the secreted protein factor X. In our RNA-seq data, where we compared F4/80+ Csf1r+ and F4/80+ Csf1r- cells, factor X emerged as one of the top 20 genes. Previous studies have associated its expression with granulocytes and macrophages. We observed its upregulation following bone injury and subsequent downregulation upon macrophage depletion, which was concurrent with changes in Wnt signaling.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Most of the objectives outlined in the grant application have been met successfully. Our research concepts are well-defined, and the experimental methodologies employed are strongly backed by resources available at our research institute.
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| Strategy for Future Research Activity |
After identifying factor "X", we will proceed with in vitro experiments. Our strategy involves introducing recombinant "X" into the culture medium of bone marrow stromal cells, with and without specific osteogenic agents. We will assess the impact of "X" on osteoblast differentiation through assays such as Alp or alizarin red staining. Additionally, we will evaluate the mRNA expression and protein levels of Wnts.
Although we initially planned to generate "A"-Cre "X" flox/flox conditional knockout (cKO) mice and observe their bone regeneration phenotype, we intend to start with Vav1-Cre instead. Finally, we will assess the effect of recombinant "X", with macrophage ablation through injection or Matrigel embedding at the bone injury site, to investigate its role in accelerating bone healing.
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