Fig. 7 | Signal Transduction and Targeted Therapy

Fig. 7

From: Porphyromonas gingivalis aggravates atherosclerotic plaque instability by promoting lipid-laden macrophage necroptosis

Fig. 7The alternative text for this image may have been generated using AI.

HDAC2 is recruited to the promoter by FOXO3 and inhibits MSR1 transcription. a Potential FOXO3 binding sites on mouse Msr1 promoter predicted by JASPAR database. b CHIP was conducted using FOXO3 antibody and IgG (negative control). c Vector information of the wild-type Msr1 promoter (−496 /−490) and its mutation/depletion mutants. d Dual luciferase reporter assay of the activities of the wild-type Msr1 promoter, and its mutation and depletion mutants in macrophages loaded with ox-LDL (60 μg/mL). n = 4 per group. e Dual luciferase reporter assay of the activities of the wild-type Msr1 promoter in macrophages loaded with ox-LDL (60 μg/mL) and infected with Pg or KDP136 (MOI = 100). n = 4 per group. f, g CHIP-PCR analyses of the histone H3 and histone H4 acetylation level in ox-LDL (60 μg/mL)-loaded macrophages treated with Pg or KDP136 (MOI = 100). n = 4 per group. qRT-PCR analyses of Msr1 expression (h), flow cytometry analyses of the ox-LDL uptake (i) and the ratio of PI+ cells (j) in ox-LDL (60 μg/mL)-loaded macrophages pre-administrated with TSA (1 μM) and challenged with Pg (MOI = 100) for 24 h. n = 4 per group. k FOXO3 and HDAC2 binding detection by Co-IP in ox-LDL (60 μg/mL) loaded macrophages infected with Pg or KDP136 (MOI = 100) for 24 h. l FOXO3 and HDAC2 binding detection by Co-IP in si-Foxo3 transfected macrophages upon ox-LDL (60 μg/mL) stimulation for 24 h. m Schematic diagram showing the mechanism of Pg-promoted macrophage necroptosis. In macrophages, gingipains secreted by Pg directly hydrolyze FOXO3 in the cytoplasm, thereby inhibiting its nuclear translocation. Additionally, Pg-LPS activates MAPK/ERK-mediated phosphorylation of FOXO3, promoting its nuclear export, and subsequent ubiquitination (Ub) and degradation. The reduction in FOXO3 levels diminishes HDAC2 binding to the MSR1 promoter and increases promoter acetylation, leading to upregulation of MSR1 expression. This enhanced MSR1 expression promotes lipid uptake and the following oxidative stress, ultimately triggering macrophage necroptosis. Diagram is generated by figdraw.com. Results were represented as mean ± SD. Data were analyzed by one-way ANOVA (d, e, h, i, j), or Kruskal–Wallis test (f, g). ****P < 0.0001; ***P < 0.001; **P < 0.01; *P < 0.05

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