Résumé
Objective:To investigate the effect and underlying mechanism of BRCC3 knockout on acute GVHD(aGVHD) of mice.Methods:A total of 12 recipient C57BL/6J mice were divided into two groups, including 6 wild type(WT) and BRCC3 -/-(KO). The recipients were exposed to 4.5 Gy + 4.5 Gy 60Co γ-rays in total body irradiation (TBI) at 30 min intervals. At 6 h post-irradiation, 1×10 7bone marrow cells and 8×10 6 splenocytes from BALB/c mice were infused into C57BL/6J mouse via tail vein to develop aGVHD mouse model. BRCC3 was specifically knocked out in aGVHD mouse model. The organ damage was examined through histopathology. The levels of serum cytokines were measured by enzyme-linked immuno sorbent assay (ELISA) and cytometric bead array (CBA), respectively. Spleen, liver and small intestine lymphocytes were isolated at 9 d post-transplantation, and the infiltration and activation of T cells in the target organs were assayed using flow cytometry. Results:The absence of BRCC3 in recipient mice significantly shortened survival ( P<0.05) with increased liver injury of aGVHD mice. In BRCC3 -/-recipient mice, the proportions of CD8+ T cells and CD8+ CD25+ T cells were significantly higher than those in the spleen( t=6.53, 5.52, P<0.05), and the proportions of CD8+ T cells and CD8+ CD25+ T cells were significantly increased in the liver ( t=3.74, 3.19, P<0.05). Similarly, the proportions of CD8+ T cells, CD8+ CD25+ T cells and CD8+ CD69+ T cells were significantly elevated in the small intestine ( t=3.52, 4.06, 3.29, P<0.05). Conclusions:BRCC3 deletion increased the proliferation and activation of donor CD8+ T cells and aggravated aGVHD, which might provide a new prevention and treatment target for aGVHD.
Résumé
Objective To construct BRCC3(BRCA1/BRCA2-containing complex subunit 3)gene knockout mice and preliminarily study the phenotypes.Methods Using the Cas9/sgRNA-Mediated genome Editing, the BRCC3 knockout mouse models were constructed.Genomic DNAs of mouse tail tissues were extracted and identified, the genotypes of mice were determined at the DNA level,and RNAs and proteins of tissues, such as the heart, liver, spleen, lung, kidney of mice were extracted and the expression of BRCC3 gene was detected by real-time-PCR and Western blotting(WB).The trend of relative body mass change and indexes that might affect the growth development and metabolism were observed. Major organs were hematoxylin-eosin(HE)stained and observed.The routine blood test of peripheral blood of mice was conducted.Results The mouse model of BRCC3 knockout was successfully constructed.BRCC3 knockout mouse survived and were fertile, indexes of blood lipid and liver function were normal, organs were not degenerative and indexes of peripheral blood in routine blood test were all in the normal range.The relative body mass of BRCC3 knockout mice was higher than that of wild type mice,and the level of serum cholesterol was increased.Conclusion BRCC3 may be involved in relative body mass regulation and cholesterol metabolism in mice.