Fig 1: Inhibition of highly expressed PCSK9 reduced infarct size, inflammation, and myocardial fibrosis and improved cardiac function after 7 days of AMI. (a–c) Cardiac function measured by echocardiography, n = 5. (d) TTC staining showed the infarct size and quantitative analysis by ImageJ in each group, n = 5. (e) Masson staining for infarct size and myocardial fibrosis. Scale bar = 1 µm, n = 5. (f) Quantitative analysis by ImageJ for collagen volume fraction and percentage infarct size of hearts in (e). (g) HE staining for the infract regions in hearts. Scale bar = 50 µm, n = 5, and quantification of inflammatory cell infiltration. *P < 0.05; **P < 0.01; ***P < 0.001; ns: not significant.
Fig 2: High expression of PCSK9 after acute myocardial infarction and the relationship between cardiac function. (a, b) Compared with WT control and WT sham group, the mice after AMI have a high level of PCSK9 protein and mRNA. (c) LVEF% and LVIDd measured by echocardiography 7 days after AMI, n = 6. (d) The correlation between the level of PCSK9 protein and cardiac function EF%, LVIDs in the mice after AMI, n = 10. ∗P < 0.05; ∗∗P < 0.01; ∗∗∗P < 0.001; ns: not significant.
Fig 3: Systemic depletion of macrophages reduced the benefits of PCSK9 knockout in cardiac repair after myocardial infarction. (a) After being adaptively fed for 6 days, Cl2MDP or PBS were injected into the tail vein to systemically deplete macrophages. (b) Immunohistochemical staining for F4/80 expression in mouse hearts from Cl2MDP- and PBS-treated mice after myocardial infarction. Scale bar = 50 μm, n = 5. Quantitative analysis by ImageJ for F4/80+ cells of myocardium in (b). (c, d) Cardiac function measured by echocardiography after Cl2MDP and PBS treatment in the WT ischemia group, n = 4. (e, f) Cardiac function measured by echocardiography after Cl2MDP and PBS treatment in the PCSK9−/− ischemia group, n = 4. ∗P < 0.05; ∗∗P < 0.01; ∗∗∗P < 0.001; ns: not significant.
Fig 4: PCSK9 regulated M1 macrophage polarization by targeting TLR4. Representative images of Western blots for TLR4 and downstream MyD88/NF-κB in WT/PCSK9−/− mouse myocardium after ischemia or sham, n = 3. (b) Protein levels of TLR4 and downstream MyD88/NF-κB of (a). (c) Representative images of Western blots for TLR4 and downstream MyD88/NF-κB in LPS/IL4-stimulated RAW264.7 cells after cocultivation with PCSK9 protein for 24 h, n = 3. (d) Protein levels of TLR4 and downstream MyD88/NF-κB of (c). (e)TLR4 inhibitor (TAK242) was used to analyze whether TLR4 is involved in PCSK9-regulated macrophage polarization; (f) protein levels of IL6, iNOS, TLR4, and downstream MyD88/NF-κB of (e). ∗P < 0.05; ∗∗P < 0.01; ∗∗∗P < 0.001; ns: not significant.
Fig 5: PCSK9 knockout inhibited M1 polarization and promoted M2 polarization in myocardial macrophages after infarction. (a) Representative immunofluorescence staining showing the percentages of M1 (F4/80+iNOS+CD206−) and M2 (F4/80+iNOS−CD206+) in WT/PCSK9−/− mouse myocardium after ischemia or sham. Nuclei were counterstained with DAPI. Scale bar = 50 μm, n = 5. Quantitative analysis of the percentage of M1 and M2 macrophages of (a). (b, c) q-PCR analysis of IL-6, iNOS, TGF-β, and CD206 mRNA expression in WT/PCSK9−/− mouse myocardium after ischemia or sham, n = 3. (d) Representative images of Western blots for PCSK9, IL6, iNOS, and TGF-β in WT/PCSK9−/− mouse myocardium after ischemia or sham, n = 3.
Supplier Page from Abcam for Mouse PCSK9 peptide