Galectin-12 enhances inflammation by promoting M1 polarization of macrophages and reduces insulin sensitivity in adipocytes

Galectin-12 is a member of an animal lectin family with affinity for β-galactosides and containing consensus amino acid sequences. Here, we found that galectin-12 was expressed in macrophages and thus aimed to determine how galectin-12 affects inflammation and macrophage polarization and activation. The ablation of galectin-12 did not affect bone marrow cells to differentiate into macrophages, but reduced phagocytic activity against Escherichia coli and lowered the secretion of nitric oxide. The ablation of galectin-12 also resulted in the polarization of macrophages into the M2 direction, as indicated by increases in the levels of M2 markers, namely, resistin-like β (FIZZ1) and chitinase 3-like 3 (Ym1), as well as a reduction in the expression levels of a number of M1 pro-inflammatory cytokines. We found that the diminished expression of pro-inflammatory cytokines in macrophages resulting from galectin-12 deletion was due to reduced activation of IKKα/β, Akt and ERK, which in turn caused decreased activation of NF-B and activator protein 1. The activation of STAT3 was much higher in Gal12–/– macrophages activated by lipopolysaccharide, which was correlated with higher levels of IL-10. Adipocytes showed higher insulin sensitivity when treated with Gal12–/– macrophage-conditioned media than those treated with Gal12+/+ macrophages. We conclude galectin-12 negatively regulates macrophage polarization into the M2 population, resulting ...

Source: Glycobiology - August 7, 2016 Category: Biology Authors: Wan, L., Lin, H.-J., Huang, C.-C., Chen, Y.-C., Hsu, Y.-A., Lin, C.-H., Lin, H.-C., Chang, C.-Y., Huang, S.-H., Lin, J.-M., Liu, F.-T. Tags: Original articles Source Type: research