👤 Miyu Yoshinaga

Apolipoprotein (apo) E is the major cholesterol carrier in the central nervous system (CNS); however, the clinical relevance of its cysteine-thiol redox status in cerebrospinal fluid (CSF) remains unclear. We investigated whether CSF apoE redox indices (redox-IDX-apoE) reflect cholesterol transport efficiency and disease-specific pathologies. We quantified reduced (red), reversibly oxidized (roxi), and irreversibly oxidized (oxi) apoE in CSF and serum using a maleimide-based band-shift assay. We analyzed relationships between redox-IDX-apoE, CSF cholesterol (TC) level, and the TC/apoE ratio (inverse transport efficiency) in patients with apoE3/E3 and identified transport determinants using isometric log-ratio (ILR) regression. Significant but only moderate correlations between CSF and serum indices suggested distinct redox behavior in the two compartments. ApoE3/E4 carriers exhibited higher oxi-apoE, reflecting reduced buffering capacity. In apoE3/E3 CSF, aging increased roxi/total and decreased red/roxi, suggesting a shift toward oxidized forms. CSF TC level positively correlated with roxi-related indices. Conversely, the TC/apoE ratio negatively correlated with red/roxi, indicating that red-apoE supports higher efficiency. ILR analysis confirmed that maintaining the reduced monomeric state, rather than the reversibly oxidized form, was independently associated with improved transport efficiency. Diagnostic groups exhibited distinct signatures: neurodegenerative disorders showed elevated irreversible oxidation, whereas neuroimmunological and infectious conditions exhibited profiles suggestive of reversible and acute oxidation, respectively. The CSF apoE redox status links local redox balance to cholesterol handling and reflects CNS pathophysiology. Maintaining reduced cysteine-thiol appears important for functional capacity, whereas a shift toward oxidation reflects a trade-off between buffering ability and transport efficiency. These indices may serve as potential biomarkers. Show less

Obesity, a risk factor for atherosclerosis development and progression, is marked by excessive reactive oxygen species (ROS) production. We previously demonstrated that high-glucose (HG) conditions induce mitochondrial ROS (mtROS) production in aortic endothelial cells (ECs). However, the link between elevated mtROS levels in obesity and atherosclerosis progression remains unclear. This study aimed to investigate whether endothelial-specific mtROS suppression by overexpressing manganese superoxide dismutase (MnSOD) could attenuate atherosclerosis progression in high-fat diet (HFD)-induced obese apolipoprotein E-deficient (ApoE KO) mice. Atherosclerotic lesion formation did not differ significantly between normal chow-fed control ApoE KO mice and endothelial cell-specific MnSOD-overexpressing ApoE KO (eMnSOD-Tg/ApoE KO) mice. However, in HFD-fed groups, eMnSOD-Tg/ApoE KO mice exhibited reduced atherosclerotic lesion size, decreased relative ROS levels, and lower Our findings demonstrate that endothelial-specific MnSOD overexpression suppresses obesity-related atherosclerosis in ApoE KO mice. mtROS plays a pivotal role in obesity-associated atherosclerosis, and targeting endothelial mtROS may offer a therapeutic strategy for preventing vascular complications in obesity. Show less

Atherosclerosis is a chronic inflammatory disease wherein macrophage polarization critically influences lesion development. Dipeptidyl peptidase-4 (DPP4), a serine protease expressed on immune cells, has been implicated in vascular inflammation; however, its cell type-specific roles remain unclear. This study aimed to determine whether Dpp4 deficiency, particularly in hematopoietic cells, affects macrophage polarization and atherosclerosis progression. Using Apoe-knockout (ApoeKO) and Apoe- and Dpp4-double knockout mice as well as bone marrow transplantation models, we evaluated the impact of systemic and myeloid-specific Dpp4 deficiency on macrophage phenotype and atherogenesis. In bone marrow-derived macrophages, Dpp4 deficiency enhanced M2 marker expression (Arg1, Ym1, Mgl2, and Fizz1) and increased the proportion of CD206 Show less

Identifying patients with vulnerable plaque who have poor prognosis among those with coronary artery disease (CAD) is crucial to deciding future therapeutic interventions. We previously reported that male CAD patients with low anti-apolipoprotein B-100 autoantibody (anti-apoB-100 Ab) levels were at an increased risk of developing unstable plaque lesions. This study focused on the autoantibodies against lipoprotein lipase (LPL), a key enzyme in triglyceride metabolism, which is another risk factor for atherosclerosis, and investigated their association with plaque characteristics. We measured serum anti-LPL Ab levels using a homemade enzyme-linked immunosorbent assay in 80 male CAD patients. Coronary plaque properties were evaluated using iMAP Serum anti-LPL Ab levels were not correlated with plaque burden but were significantly negatively and positively correlated with fibrotic and necrotic plaques, respectively. High-risk patients with low anti-apoB-100 Ab levels were divided into groups according to their anti-LPL Ab levels. The group with high anti-LPL Ab levels exhibited more necrotic plaques and fewer fibrotic plaques as well as higher remnant-like lipoprotein particle levels than the group with low anti-LPL Ab levels. Serum anti-LPL Ab levels can serve as a marker of plaque instability in CAD patients and can help identify higher-risk cases when combined with anti-apoB-100 Ab levels. Show less

Atypical protein kinase C (aPKC) has been implicated in several signaling pathways such as cell polarity, cell survival, and cell differentiation. In contrast to other PKCs, aPKC is unique in having the PB1 (Phox and Bem 1) domain in the N terminus. The aPKC PB1 domain binds with ZIP/p62, Par6, or MEK5 through a PB1-PB1 domain interaction that controls the localization of aPKC. Here, we determined the three-dimensional structure of the PB1 domain of PKCiota by NMR and found that the PB1 domain adopts a ubiquitin fold. The OPCA (OPR, PC, and AID) motif inserted into the ubiquitin fold was presented as a betabetaalpha fold in which the side chains of conserved Asp residues were oriented to the same direction to form an acidic surface. This structural feature suggested that the acidic surface of the PKCiota PB1 domain interacted with the basic surface of the target PB1 domains, and this was confirmed in the case of the PKCiota-ZIP/p62 complex by mutational analysis. Interestingly, in the PKCiota PB1 domain a conserved lysine residue was located on the side opposite to the OPCA motif-presenting surface, suggesting dual roles for the PKCiota PB1 domain in that it could interact with either the conserved lysine residue or the acidic residues on the OPCA motif of the target PB1 domains. Show less