| First Author | Bandaru S | Year | 2019 |
| Journal | Circulation | Volume | 140 |
| Issue | 1 | Pages | 67-79 |
| PubMed ID | 31014088 | Mgi Jnum | J:292625 |
| Mgi Id | MGI:6448549 | Doi | 10.1161/CIRCULATIONAHA.119.039697 |
| Citation | Bandaru S, et al. (2019) Targeting Filamin A Reduces Macrophage Activity and Atherosclerosis. Circulation 140(1):67-79 |
| abstractText | BACKGROUND: The actin-binding protein FLNA (filamin A) regulates signal transduction important for cell locomotion, but the role of macrophage-specific FLNA during atherogenesis has not been explored. METHODS: We analyzed FLNA expression in human carotid atherosclerotic plaques by immunofluorescence. We also produced mice with Flna-deficient macrophages by breeding conditional Flna-knockout mice ( Flna (o/fl)) with mice expressing Cre from the macrophage-specific lysosome M promoter ( LC). Atherosclerosis in vivo was studied by transplanting bone marrow from male Flna (o/fl)/ LC mice to atherogenic low-density lipoprotein receptor-deficient ( Ldlr(-/-)) mice; and by infecting Flna (o/fl) and Flna (o/fl)/ LC mice with AdPCSK9 (adenoviral vector overexpressing proprotein convertase subtilisin/kexin type 9). Furthermore, C57BL/6 mice were infected with AdPCSK9 and then treated with the calpain inhibitor calpeptin to inhibit FLNA cleavage. RESULTS: We found that macrophage FLNA expression was higher in advanced than in intermediate human atherosclerotic plaques. Flna (o/fl)/ LC macrophages proliferated and migrated less than controls; expressed lower levels of phosphorylated AKT and ERK1/2; exhibited reduced foam cell formation and lipid uptake; and excreted more lipids. The deficiency of Flna in macrophages markedly reduced the size of aortic atherosclerotic plaques in both Ldlr(-/-BMT: Flnao/fl/LC) and AdPCSK9-infected Flna (o/fl)/ LC mice. Intima/media ratios and numbers of CD68-positive macrophages in atherosclerotic plaques were lower in Flna-deficient mice than in control mice. Moreover, we found that STAT3 interacts with a calpain-cleaved carboxyl-terminal fragment of FLNA. Inhibiting calpain-mediated FLNA cleavage with calpeptin in macrophages reduced nuclear levels of phosphorylated STAT3, interleukin 6 secretion, foam cell formation, and lipid uptake. Finally, calpeptin treatment reduced the size of atherosclerotic plaques in C57BL/6 mice infected with AdPCSK9. CONCLUSIONS: Genetic inactivation of Flna and chemical inhibition of calpain-dependent cleavage of FLNA impaired macrophage signaling and function, and reduced atherosclerosis in mice, suggesting that drugs targeting FLNA may be useful in the treatment of atherosclerosis. |
