Here, we addressed whether a reduction of iNOS-mediated oxidative stress
remobilizes macrophage-derived foam cells and may reverse plaque formation. Methods: Migration of RAW264.7 cells and bone marrow cells was quantified using a modified Boyden chamber. iNOS expression, phalloidin staining, focal adhesion kinase phosphorylation, lipid peroxides, nitric oxide (NO) and reactive oxygen species (ROS) production were assessed. Results: oxLDL treatment significantly reduced cell migration compared to unstimulated cells (p smaller than 0.05). This migratory arrest was reversed by co-incubation with a pharmacologic iNOS inhibitor 1400W (p smaller than 0.05) and iNOS-siRNA (p bigger than 0.05). Furthermore, apoE/iNOS double knockout macrophages selleck inhibitor do not show migratory arrest in response to oxLDL uptake, compared to apoE knockout controls (p bigger
than 0.05). We documented significantly increased iNOS expression following oxLDL treatment and downregulation using 1400W and small inhibitory RNA (siRNA). iNOS inhibition was associated with a reduction in NO and peroxynitrite (ONOO-)- and increased superoxide generation. Trolox treatment of buy AZD1390 RAW264.7 cells restored migration indicating that peroxynitrite mediated lipid peroxide formation is involved in the signaling pathway mediating cell arrest.. Conclusions: Here, we provide pharmacologic and genetic evidence that oxLDL induced iNOS expression inhibits macrophage-derived foam cell migration. Therefore, reduction of peroxynitrite LEE011 concentration and possibly lipid hydroperoxide levels in plaques represents
a valuable therapeutic approach to reverse migratory arrest of macrophage-derived foam cells and to impair plaque formation. (C) 2014 Elsevier Ireland Ltd. All rights reserved.”
“Mitophagy, or mitochondria autophagy, plays a critical role in selective removal of damaged or unwanted mitochondria. Several protein receptors, including Atg32 in yeast, NIX/BNIP3L, BNIP3 and FUNDC1 in mammalian systems, directly act in mitophagy. Atg32 interacts with Atg8 and Atg11 on the surface of mitochondria, promoting core Atg protein assembly for mitophagy. NIX/BNIP3L, BNIP3 and FUNDC1 also have a classic motif to directly bind LC3 (Atg8 homolog in mammals) for activation of mitophagy. Recent studies have shown that receptor-mediated mitophagy is regulated by reversible protein phosphorylation. Casein kinase 2 (CK2) phosphorylates Atg32 and activates mitophagy in yeast. In contrast, in mammalian cells Src kinase and CK2 phosphorylate FUNDC1 to prevent mitophagy. Notably, in response to hypoxia and FCCP treatment, the mitochondrial phosphatase PGAM5 dephosphorylates FUNDC1 to activate mitophagy. Here, we mainly focus on recent advances in our understanding of the molecular mechanisms underlying the activation of receptor-mediated mitophagy and the implications of this catabolic process in health and disease.