Distinct roles of SOX9 in self-renewal of progenitors and mesenchymal transition of the endothelium.

Regenerative capabilities of the endothelium rely on vessel-resident progenitors termed endothelial colony forming cells (ECFCs). This study aimed to investigate if these progenitors are impacted by conditions (i.e., obesity or atherosclerosis) characterized by increased serum levels of oxidized low-density lipoprotein (oxLDL), a known inducer of Endothelial-to-Mesenchymal Transition (EndMT). Our investigation focused on understanding the effects of EndMT on the self-renewal capabilities of progenitors and the associated molecular alterations. In the presence of oxLDL, ECFCs displayed classical features of EndMT, through reduced endothelial gene and protein expression, function as well as increased mesenchymal genes, contractility, and motility. Additionally, ECFCs displayed a dramatic loss in self-renewal capacity in the presence of oxLDL. RNA-sequencing analysis of ECFCs exposed to oxLDL validated gene expression changes suggesting EndMT and identified SOX9 as one of the highly differentially expressed genes. ATAC sequencing analysis identified SOX9 binding sites associated with regions of dynamic chromosome accessibility resulting from oxLDL exposure, further pointing to its importance. EndMT phenotype and gene expression changes induced by oxLDL in vitro or high fat diet (HFD) in vivo were reversed by the silencing of SOX9 in ECFCs or the endothelial-specific conditional knockout of Sox9 in murine models. Overall, our findings support that EndMT affects vessel-resident endothelial progenitor's self-renewal. SOX9 activation is an early transcriptional event that drives the mesenchymal transition of endothelial progenitor cells. The identification of the molecular network driving EndMT in vessel-resident endothelial progenitors presents a new avenue in understanding and preventing a range of condition where this process is involved.

Dysregulated lipid metabolism and intervertebral disc degeneration: the important role of ox-LDL/LOX-1 in endplate chondrocyte senescence and calcification.

BACKGROUND: Lipid metabolism disorders are associated with degeneration of multiple tissues and organs, but the mechanism of crosstalk between lipid metabolism disorder and intervertebral disc degeneration (IDD) has not been fully elucidated. In this study we aim to investigate the regulatory mechanism of abnormal signal of lipid metabolism disorder on intervertebral disc endplate chondrocyte (EPC) senescence and calcification. METHODS: Human intervertebral disc cartilage endplate tissue, cell model and rat hyperlipemia model were performed in this study. Histology and immunohistochemistry were used to human EPC tissue detection. TMT-labelled quantitative proteomics was used to detect differential proteins, and MRI, micro-CT, safranin green staining and immunofluorescence were performed to observe the morphology and degeneration of rat tail intervertebral discs. Flow cytometry, senescence-associated ß-galactosidase staining, alizarin red staining, alkaline phosphatase staining, DCFH-DA fluorescent probe, and western blot were performed to detect the expression of EPC cell senescence, senescence-associated secretory phenotype, calcification-related proteins and the activation of cell senescence-related signaling pathways. RESULTS: Our study found that the highly expressed oxidized low-density lipoprotein (ox-LDL) and Lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) in human degenerative EPC was associated with hyperlipidemia (HLP). TMT-labelled quantitative proteomics revealed enriched pathways such as cell cycle regulation, endochondral bone morphogenesis and inflammation. The rat model revealed that HLP could induce ox-LDL, LOX-1, senescence and calcification markers high expression in EPC. Moreover, we demonstrated that ox-LDL-induced EPCs senescence and calcification were dependent on the LOX-1 receptor, and the ROS/P38-MAPK/NF-κB signaling pathway was implicated in the regulation of senescence induced by ox-LDL/LOX-1 in cell model. CONCLUSIONS: So our study revealed that ox-LDL/LOX-1-induced EPCs senescence and calcification through ROS/P38-MAPK/NF-κB signaling pathway, providing information on understanding the link between lipid metabolism disorders and IDD.

Oxidized low-density lipoproteins impair the pro-atherosclerotic effect of granulocyte-macrophage-colony-stimulating factor-producing T helper cells on macrophages.

T cells contribute to the pathogenesis of atherosclerosis. However, the presence and function of granulocyte-macrophage-colony-stimulating factor (GM-CSF)-producing T helper (ThGM) cells in atherosclerosis development is unknown. This study aims to characterize the phenotype and function of ThGM cells in experimental atherosclerosis. Atherosclerosis was induced by feeding apolipoprotein E knockout (ApoE-/-) mice with a high-fat diet. Aortic ThGM cells were detected and sorted by flow cytometry. The effect of oxidized low-density lipoprotein (oxLDL) on ThGM cells and the impact of ThGM cells on macrophages were evaluated by flow cytometry, quantitative RT-PCR, oxLDL binding/uptake assay, immunoblotting and foam cell formation assay. We found that GM-CSF+IFN-γ- ThGM cells existed in atherosclerotic aortas. Live ThGM cells were enriched in aortic CD4+CCR6-CCR8-CXCR3-CCR10+ T cells. Aortic ThGM cells triggered the expression of interleukin-1ß (IL-1ß), tumour necrosis factor (TNF), interleukin-6 (IL-6) and C-C motif chemokine ligand 2 (CCL2) in macrophages. Besides, aortic ThGM cells expressed higher CD69 than other T cells and bound to oxLDL. oxLDL suppressed the cytokine expression in ThGM cells probably via inhibiting the signal transducer and activator of transcription 5 (STAT5) signalling. Furthermore, oxLDL alleviated the effect of ThGM cells on inducing macrophages to produce pro-inflammatory cytokines and generate foam cells. The nuclear receptor subfamily 4 group A (NR4A) members NR4A1 and NR4A2 were involved in the suppressive effect of oxLDL on ThGM cells. Collectively, oxLDL suppressed the supportive effect of ThGM cells on pro-atherosclerotic macrophages.

14-3-3-η interacts with BCL-2 to protect human endothelial progenitor cells from ox-LDL-triggered damage.

Oxidized low-density lipoprotein (ox-LDL) causes dysfunction of endothelial progenitor cells (EPCs), and we recently reported that 14-3-3-η can attenuate the damage triggered by ox-LDL in EPCs. However, the molecular mechanisms by which 14-3-3-η protects EPCs from the damage caused by ox-LDL are not fully understood. In this study, we observed that the expression of 14-3-3-η and BCL-2 were downregulated in ox-LDL-treated EPCs. Overexpression of 14-3-3-η in ox-LDL-treated EPC significantly increased BCL-2 level, while knockdown of BCL-2 reduced 14-3-3-η expression and mitigated the protective effect of 14-3-3-η on EPCs. In addition, we discovered that 14-3-3-η colocalizes and interacts with BCL-2 in EPCs. Taken together, these data suggest that 14-3-3-η protects EPCs from ox-LDL-induced damage by its interaction with BCL-2.

Oxidized-LDL Induces Metabolic Dysfunction in Retinal Pigment Epithelial Cells.

Recently, mitochondrial dysfunction has gained attention as a causative factor in the pathogenesis and progression of age-related macular degeneration (AMD). Mitochondrial damage plays a key role in metabolism and disrupts the balance of intracellular metabolic pathways, such as oxidative phosphorylation (OXPHOS) and glycolysis. In this study, we focused on oxidized low-density lipoprotein (ox-LDL), a major constituent of drusen that accumulates in the retina of patients with AMD, and investigated whether it could be a causative factor for metabolic alterations in retinal pigment epithelial (RPE) cells. We found that prolonged exposure to ox-LDL induced changes in fatty acid ß-oxidation (FAO), OXPHOS, and glycolytic activity and increased the mitochondrial reactive oxygen species production in RPE cells. Notably, the effects on metabolic alterations varied with the concentration and duration of ox-LDL treatment. In addition, we addressed the limitations of using ARPE-19 cells for retinal disease research by highlighting their lower barrier function and FAO activity compared to those of induced pluripotent stem cell-derived RPE cells. Our findings can aid in the elucidation of mechanisms underlying the metabolic alterations in AMD.

Human In Vitro Oxidized Low-Density Lipoprotein (oxLDL) Increases Urinary Albumin Excretion in Rats.

Hypercholesterolemia-associated oxidative stress increases the formation of oxidized low-density lipoprotein (oxLDL), which can affect endothelial cell function and potentially contribute to renal dysfunction, as reflected by changes in urinary protein excretion. This study aimed to investigate the impact of exogenous oxLDL on urinary excretion of albumin and nephrin. LDL was isolated from a patient with familial hypercholesterolemia (FH) undergoing lipoprotein apheresis (LA) and was oxidized in vitro with Cu (II) ions. Biochemical markers of LDL oxidation, such as TBARS, conjugated dienes, and free ε-amino groups, were measured. Wistar rats were treated with a single intraperitoneal injection of PBS, LDL, or oxLDL (4 mg of protein/kg b.w.). Urine was collected one day before and two days after the injection. We measured blood lipid profiles, urinary protein excretion (specifically albumin and nephrin), and markers of systemic oxidative stress (8-OHdG and 8-iso-PGF2α). The results showed that injection of oxLDL increased urinary albumin excretion by approximately 28% (310 ± 27 µg/24 h vs. 396 ± 26 µg/24 h, p = 0.0003) but had no effect on nephrin excretion. Neither PBS nor LDL had any effect on urinary albumin or nephrin excretion. Additionally, oxLDL did not affect systemic oxidative stress. In conclusion, hypercholesterolemia may adversely affect renal function through oxidatively modified LDL, which interferes with the renal handling of albumin and leads to the development of albuminuria.

Sirtuin 6 Deacetylates Apoptosis-Associated Speck-Like Protein (ASC) to Inhibit Endothelial Cell Pyroptosis in Atherosclerosis.

Endothelial cell dysfunction is the main pathology of atherosclerosis (AS). Sirtuin 6 (SIRT6), a deacetylase, is involved in AS progression. This study aimed to investigate the impacts of SIRT6 on the pyroptosis of endothelial cells and its underlying mechanisms. ApoE-/- mice were fed a high-fat diet (HFD) to establish the AS mouse model, atherosclerotic lesions were evaluated using oil red O staining, and blood lipids and inflammatory factors were measured using corresponding kits. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to establish the cell model, and pyroptosis was evaluated by flow cytometry, ELISA, and western blot. Immunoprecipitation (IP), co-IP, western blot, and immunofluorescence were used to detect the molecular mechanisms. The results showed that SIRT6 expression was downregulated in the blood of HFD-induced mice and ox-LDL-induced HUVECs. Overexpression of SIRT6 reduced atherosclerotic lesions, blood lipids, and inflammation in vivo and suppressed pyroptosis of HUVECs in vitro. Moreover, SIRT6 interacted with ASC to inhibit the acetylation of ASC, thus, reducing the interaction between ASC and NLRP3. Moreover, SIRT6 inhibits endothelial cell pyroptosis in the aortic roots of mice by deacetylating ASC. In conclusion, SIRT6 deacetylated ASC to inhibit its interaction with NLRP3 and then suppressed pyroptosis of endothelial cells, thus, decelerating the progression of AS. The findings provide new insights into the function of SIRT6 in AS.

Oxidized low-density lipoprotein changes the inflammatory status and metabolomics profiles in human and mouse macrophages and microglia.

The conjunctiva of primary open angle glaucoma patients showed high level of oxidized low-density lipoprotein (ox-LDL), which is associated with the inflammatory response. Microglia and macrophages are the immune cells involved in retinal ganglion cell survival regulation; yet, their roles of the ox-LDL-induced inflammation in glaucoma remain elusive. Here we aimed to investigate the lipid uptake, inflammatory cytokine expression, and metabolomics profiles of human and murine-derived microglial and macrophage cell lines treated with ox-LDL. Under the same ox-LDL concentration, macrophages exhibited higher lipid uptake and expression of pro-inflammatory cytokines as compared to microglia. The ox-LDL increased the levels of fatty acid metabolites in macrophages and sphingomyelin metabolites in microglia. In summary, this study revealed the heterogeneity in the inflammatory capacity and metabolic profiles of macrophages and microglia under the stimulation of ox-LDL.

Computational and experimental investigations of a novel aptamer targeting oxidized low-density lipoprotein.

Oxidized low-density lipoprotein (oxLDL) induces the formation of atherosclerotic plaques. Apolipoprotein B100 (apoB100) is a crucial protein component in low-density lipoprotein (LDL), which includes oxLDL. The oxidation of amino acids and subsequent alterations in their structure generate oxLDL, which is a significant biomarker for the initial phases of coronary artery disease. This study employed molecular docking and molecular dynamics utilizing the MM/GBSA method to identify aptamers with a strong affinity for oxidized apoB100. Molecular docking and molecular dynamics were performed on two sequences of the aptamer candidates (aptamer no.11 (AP11: 5'-CTTCGATGTAGTTTTTGTATGGGGTGCCCTGGTTCCTGCA-3') and aptamer no.26 (AP26: 5'-GCGAACTCGCGAATCCAGAACGGGCTCGGTCCCGGGTCGA-3')), yielding respective binding free energies of -149.08 kcal/mol and -139.86 kcal/mol. Interaction modeling of the simulation revealed a strong hydrogen bond between the AP11-oxidized apoB100 complexes. In an aptamer-based gold nanoparticle (AuNP) aggregation assay, AP11 exhibits a color shift from red to purple with the highest absorbance ratio, and shows strong binding affinity to oxLDL, correlating with the simulation model results. AP11 demonstrated the potential for application as a novel recognition element in diagnostic methodologies and may also contribute to future advancements in preventive therapies for coronary artery disease.

Role of Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 in Inflammation and Pathogen-Associated Interactions.

BACKGROUND: Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is known as a major receptor for oxidized low-density lipoproteins (oxLDL) and plays a significant role in the genesis of atherosclerosis. Recent research has shown its involvement in cancer, ischemic stroke, and diabetes. LOX-1 is a C-type lectin receptor and is involved in the activation of immune cells and inflammatory processes. It may further interact with pathogens, suggesting a role in infections or the host's response. SUMMARY: This review compiles the current knowledge of potential implications of LOX-1 in inflammatory processes and in host-pathogen interactions with a particular emphasis on its regulatory role in immune responses. Also discussed are genomic and structural variations found in LOX-1 homologs across different species as well as potential involvements of LOX-1 in inflammatory processes from the angle of different cell types and organ-specific interactions. KEY MESSAGES: The results presented reveal both similar and different structures in human and murine LOX-1 and provide clues as to the possible origins of different modes of interaction. These descriptions raise concerns about the suitability, particularly of mouse models, that are often used in the analysis of its functionality in humans. Further research should also aim to better understand the mostly unknown binding and interaction mechanisms between LOX-1 and different pathogens. This pursuit will not only enhance our understanding of LOX-1 involvement in inflammatory processes but also identify potential targets for immunomodulatory approaches.

Antiferroptosis therapy alleviated the development of atherosclerosis.

Ferroptosis has been confirmed to be associated with various diseases, but the relationship between ferroptosis and atherosclerosis (AS) remains unclear. Our research detailly clarified the roles of ferroptosis in three continuous and main pathological stages of AS respectively (injury of endothelial cells [ECs], adhesion of monocytes, and formation of foam cells). We confirmed that oxidized low-density lipoprotein (ox-LDL), the key factor in the pathogenesis of AS, strongly induced ferroptosis in ECs. Inhibition of ferroptosis repressed the adhesion of monocytes to ECs by inhibiting inflammation of ECs. Ferroptosis also participated in the formation of foam cells and lipids by regulating the cholesterol efflux of macrophages. Further research confirmed that ox-LDL repressedthe activity of glutathione peroxidase 4 (GPX4), the classic lipid peroxide scavenger. Treatment of a high-fat diet significantly induced ferroptosis in murine aortas and aortic sinuses, which was accompanied by AS lesions and hyperlipidemia. Treatment with ferroptosis inhibitors significantly reduced ferroptosis, hyperlipidemia, and AS lesion development. In conclusion, our research determined that ox-LDL induced ferroptosis by repressing the activity of GPX4. Antiferroptosis treatment showed promising treatment effects in vivo. Ferroptosis-associated indexes also showed promising diagnostic potential in AS patients.

The long coiled-coil protein NECC2 regulates oxLDL-induced endothelial oxidative damage and exacerbates atherosclerosis development in apolipoprotein E -/- mice.

Oxidized low density lipoprotein (oxLDL)-induced endothelial oxidative damage promotes the development of atherosclerosis. Caveolae play an essential role in maintaining the survival and function of vascular endothelial cell (VEC). It is reported that the long coiled-coil protein NECC2 is localized in caveolae and is associated with neural cell differentiation and adipocyte formation, but its role in VECs needs to be clarified. Our results showed NECC2 expression increased in the endothelium of plaque-loaded aortas and oxLDL-treated HUVECs. Down-regulation of NECC2 by NECC2 siRNA or compound YF-307 significantly inhibited oxLDL-induced VEC apoptosis and the adhesion factors expression. Remarkably, inhibition of NECC2 expression in the endothelium of apoE-/- mice by adeno-associated virus (AAV)-carrying NECC2 shRNA or compound YF-307 alleviated endothelium injury and restricted atherosclerosis development. The immunoprecipitation results confirmed that NECC2 interacted with Tyk2 and caveolin-1(Cav-1) in VECs, and NECC2 further promoted the phosphorylation of Cav-1 at Tyr14 b y activating Tyk2 phosphorylation. On the other hand, inhibiting NECC2 levels suppressed oxLDL-induced phosphorylation of Cav-1, uptake of oxLDL by VECs, accumulation of intracellular reactive oxygen species and activation of NF-κB. Our findings suggest that NECC2 may contribute to oxLDL-induced VEC injury and atherosclerosis via modulating Cav-1 phosphorylation through Tyk2. This work provides a new concept and drug target for treating atherosclerosis.

Hypoxia-induced NOS1 as a therapeutic target in hypercholesterolemia-related colorectal cancer.

BACKGROUND: It is well established that hypercholesterolemia increases the risk of atherosclerosis, especially because it reduces the availability of nitric oxide (NO). However, the relationship between hypercholesterolemia and NO in regulating colorectal cancer development and progression remains unknown. METHODS: We conducted bioinformatics analysis, qRT-PCR, ChIP-qPCR assays, luciferase report assays, clonogenic survival assays, and multiple mouse models to investigate the function and mechanism of hypercholesterolemia in regulating NO signaling. Additionally, NOS inhibitors were used to evaluate the potential of therapeutic strategy in anti-tumor response. RESULTS: Here, we show that oxidized low-density lipoprotein (oxLDL) cholesterol and its receptor LOX-1 are essential for hypercholesterolemia-induced colorectal tumorigenesis. Mechanically, the oxLDL promotes the oxidant stress-dependent induction of hypoxia signaling to transcriptionally up-regulate NO synthase (NOS) especially NOS1 expression in colorectal cancer (CRC) cells. More importantly, our results suggested that selective inhibition of NOS1 with its specific inhibitor Nω-Propyl-L-arginine is a suitable therapeutic strategy for hypercholesterolemia-related CRC with both efficacy and toxicity reduction. CONCLUSIONS: Our findings established that hypercholesterolemia induces the oxidant stress-dependent induction of hypoxia signaling to transcriptionally up-regulate NOS1 expression in CRC cells, and the clinically applicable NOS1 inhibitor Nω-Propyl-L-arginine represents an effective therapeutic strategy for hypercholesterolemia-related CRC.

Multi-model analysis of gallbladder cancer reveals the role of OxLDL-absorbing neutrophils in promoting liver invasion.

BACKGROUND: Gallbladder cancer (GBC) is the most common and lethal malignancy of the biliary tract that lacks effective therapy. In many GBC cases, infiltration into adjacent organs or distant metastasis happened long before the diagnosis, especially the direct liver invasion, which is the most common and unfavorable way of spreading. METHODS: Single-cell RNA sequencing (scRNA-seq), spatial transcriptomics (ST), proteomics, and multiplexed immunohistochemistry (mIHC) were performed on GBC across multiple tumor stages to characterize the tumor microenvironment (TME), focusing specifically on the preferential enrichment of neutrophils in GBC liver invasion (GBC-LI). RESULTS: Multi-model Analysis reveals the immunosuppressive TME of GBC-LI that was characterized by the enrichment of neutrophils at the invasive front. We identified the context-dependent transcriptional states of neutrophils, with the Tumor-Modifying state being associated with oxidized low-density lipoprotein (oxLDL) metabolism. In vitro assays showed that the direct cell-cell contact between GBC cells and neutrophils led to the drastic increase in oxLDL uptake of neutrophils, which was primarily mediated by the elevated OLR1 on neutrophils. The oxLDL-absorbing neutrophils displayed a higher potential to promote tumor invasion while demonstrating lower cancer cytotoxicity. Finally, we identified a neutrophil-promoting niche at the invasive front of GBC-LI that constituted of KRT17+ GBC cells, neutrophils, and surrounding fibroblasts, which may help cultivate the oxLDL-absorbing neutrophils. CONCLUSIONS: Our study reveals the existence of a subset of pro-tumoral neutrophils with a unique ability to absorb oxLDL via OLR1, a phenomenon induced through cell-cell contact with KRT17+ GBC cells in GBC-LI.

Machine learning-directed electrical impedance tomography to predict metabolically vulnerable plaques.

The characterization of atherosclerotic plaques to predict their vulnerability to rupture remains a diagnostic challenge. Despite existing imaging modalities, none have proven their abilities to identify metabolically active oxidized low-density lipoprotein (oxLDL), a marker of plaque vulnerability. To this end, we developed a machine learning-directed electrochemical impedance spectroscopy (EIS) platform to analyze oxLDL-rich plaques, with immunohistology serving as the ground truth. We fabricated the EIS sensor by affixing a six-point microelectrode configuration onto a silicone balloon catheter and electroplating the surface with platinum black (PtB) to improve the charge transfer efficiency at the electrochemical interface. To demonstrate clinical translation, we deployed the EIS sensor to the coronary arteries of an explanted human heart from a patient undergoing heart transplant and interrogated the atherosclerotic lesions to reconstruct the 3D EIS profiles of oxLDL-rich atherosclerotic plaques in both right coronary and left descending coronary arteries. To establish effective generalization of our methods, we repeated the reconstruction and training process on the common carotid arteries of an unembalmed human cadaver specimen. Our findings indicated that our DenseNet model achieves the most reliable predictions for metabolically vulnerable plaque, yielding an accuracy of 92.59% after 100 epochs of training.

Increased vascular deposition of oxidized LDL in untreated juvenile dermatomyositis.

BACKGROUND: Juvenile dermatomyositis (JDM) is a systemic vasculopathy associated with metabolic derangements and possible increased risk for premature atherosclerosis. Oxidation of low-density lipoprotein (LDL) in the endothelium is an early step in atherosclerotic plaque formation. It is not known if oxidized LDL is altered in children with untreated JDM. The deposition of oxidized LDL in the vasculature of muscle biopsies (MBx) from patients with untreated JDM and pediatric controls was assessed. FINDINGS: Frozen tissue sections of MRI-directed MBx from 20 female children with untreated JDM and 5 female controls were stained with DAPI and fluorescently labeled antibodies against von Willebrand factor (vWF) and LDL oxidized by copper (oxLDL). Blood vessels were identified by positive vWF staining, and total fluorescence of oxLDL within the vessel walls was measured. Children with untreated JDM had increased deposition of oxLDL in the walls of muscle vasculature compared to healthy children (difference in means ± SEM = 19.86 ± 8.195, p = 0.03). Within the JDM cohort, there was a trend towards increased oxLDL deposition with longer duration of untreated disease (r = 0.43, p = 0.06). There was no significant correlation found between oxLDL deposition and markers of acute JDM disease activity including disease activity scores or muscle enzymes. CONCLUSIONS: This study found increased deposition of oxLDL within blood vessels of children with untreated JDM supporting the concern that these children are at increased risk for premature atherosclerosis from chronic exposure to vascular oxLDL. This study highlights the importance of early diagnosis and treatment initiation to ameliorate cardiovascular damage.

Protective effect of rubber seed oil on human endothelial cells.

OBJECTIVE: This study was conducted to characterize the antioxidant and anti-inflammatory properties of Rubber Seed Oil (RSO) against atherosclerosis (AS) through the study of the protective effects and mechanisms on human umbilical vein endothelial cells (HUVECs) injury induced by oxidized low-density lipoprotein (ox-LDL). METHODS: HUVECs were treated with RSO, ox-LDL, RSO + ox-LDL, respectively, followed by cell activity testing, levels of IL-1ß, IL-6, IL-10, TNF-α, ROS, NO, the mRNA expression of eNOS and protein expression of MCP-1, VCAM-1, eNOS, TLR4, NF-κB p65、p-NF-κB p65. RESULTS: Compared with the ox-LDL group, cell viability, NO level and the expression of eNOS mRNA significantly increased. and the levels of pro-inflammatory factors such as IL-1ß, IL-6, TNF-α, IL-10, ROS were significantly decreased, which was accompanied by decreases in TLR4 mRNA, TLR4, MCP-1, VCAM-1 protein expression, as well as the ratio of NF-κB p-p65/p65 in the group treated with 250 µg/ml ox-LDL + 50 µg/ml RSO, 250 µg/ml ox-LDL + 100 µg/ml RSO, 250 µg/ml ox-LDL + 150 µg/ml RSO. CONCLUSIONS: RSO can reduce the expression of pro-inflammatory mediators, oxidative factors involved in injured vascular endothelial cells, exhibiting anti-inflammatory and antioxidant properties HUVECs exposed to ox-LDL. In addition, it may alleviate endothelial cell damage by inhibiting the TLR4/NF-κB signaling pathway.

Oxidized Low-Density Lipoprotein Decreases the Survival of Bone Marrow Stem Cells via Inhibition of Bcl-2 Expression.

Therapy with mesenchymal stem cells (MSCs) is considered an attractive strategy for the repair or regeneration of damaged tissues. However, low survival of MSCs limits their applications clinically. Oxidized low-density lipoprotein (ox-LDL) is significantly increased in patients with hyperlipidemia and decreases the survival of MSCs. Bcl-2 is critically involved in important cell functions, including cell membrane integrity and cell survival. The present study was designed to test the hypothesis that ox-LDL attenuates the survival of MSCs through suppression of Bcl-2 expression. Bone marrow MSCs from C57BL/6 mice were cultured with ox-LDL at different concentrations (0-140 µg/mL) for 24 h with native LDL as control. Ox-LDL treatment substantially decreased the survival of MSCs dose-dependently and enhanced the release of intracellular lactate dehydrogenase (LDH) in association with a significant decrease in Bcl-2 protein level without change in BAX protein expression in MSCs. Bcl-2 overexpression effectively protected MSCs against ox-LDL-induced damages with preserved cell numbers without significant increase in LDH release. Treatment with N-acetylcysteine (NAC) (1 mM) effectively preserved Bcl-2 protein expression in MSCs and significantly attenuated ox-LDL-induced decrease of cell number and increase in the release of intracellular LDH. These data indicated that ox-LDL treatment resulted in a significant damage of cell membrane and dramatically decreased the survival of MSCs dose-dependently through inhibition of Bcl-2 expression. NAC treatment significantly protected MSCs against the damage of cell membrane by ox-LDL and promoted the survival of MSCs in association with preserved Bcl-2 expression.

Cumulative Exposure to Oxidized Low-density Lipoprotein is a Potential Predictor for Prognosis in Acute Ischemic Stroke: A Cohort Study.

BACKGROUND: Oxidized Low-Density Lipoprotein (ox-LDL) is crucial in the recrudescence and prognosis of acute ischemic stroke (AIS). We aimed to probe into the influence of cumulative ox-LDL exposure on the 90-day prognosis of AIS. METHODS: Patients with AIS were recruited in this research. AIS severity at admission was estimated with infarct volumes and National Institute of Health Stroke Scale (NIHSS) scores. AIS prognosis was assessed using Modified Rankin Scale (mRS) scores at 90 days and the change in NIHSS scores from admission to discharge. Cumulative ox-LDL exposure was defined as ox-LDL level (pg/mL) multiplied by age(y). Multivariate logistic regression analysis was employed to reveal the correlation between exposure factors and the prognosis of AIS. The prognostic prediction ability of cumulative ox-LDL exposure was compared with cumulative LDL exposure by the receiver operating characteristic curve (ROC). RESULTS: Higher cumulative ox-LDL exposure was related to worse prognosis, including neurological worsening at discharge (NIHSS increasing more than 2 points) (OR = 3.02, 95% CI, 1.30-6.98, P = 0.01) and poor functional prognosis at 90 days (mRS ≥ 3) (OR = 21.21, 95% CI, 4.72-95.36, P < 0.001). As multivariate regression analysis showed, significantly increased cumulative ox-LDL exposure was relevant to poor functional prognosis at 90 days (OR = 9.92, 95% CI, 1.23-79.76, P = 0.031), but not with neurological worsening at discharge (P = 0.414). ROC curve revealed that cumulative ox-LDL exposure had a higher predictive value (AUC = 0.843, P < 0.001) for functional prognosis of AIS than cumulative LDL exposure (AUC = 0.629, P = 0.023). CONCLUSION: Cumulative ox-LDL exposure has a positive correlation with poor prognosis at 90 days of AIS, and has a more accurate predictive ability than cumulative LDL exposure.

Fcα Receptor Type I and Its Association with Atherosclerosis Development.

Objectives: Atherosclerosis is a chronic inflammatory disease characterized by lipid accumulation and local inflammation, which are regulated by the immune system. The immunological aspects of this disease are unclear. Immunoglobulin A regulates many cell responses through interactions with Fcα receptor type I (FcαRI). Anti-FcαRI antibody inhibits activating receptors by inducing an inhibitory immunoreceptor tyrosine-based activation motif configuration. However, the role of FcαRI in atherosclerosis development is unclear. Here, we investigated the utility of FcαRI targeting to induce inhibitory immunoreceptor tyrosine-based activation motif signaling in atherosclerosis treatment. Materials: ApoE-/- transgenic mice expressing the FcαRIR209L/FcRγ chimeric protein (FcαRIR209L/FcRγApoE-/- mice) were generated. We prepared an FcαRIR209L/FcRγ transfectant (I3D) from a mouse macrophage cell line (RAW264.7). Methods: Anti-FcαRI or control antibody was used to investigate a high-fat-diet-induced FcαRIR209L/FcRγApoE-/- mouse model of atherosclerosis. The antibody was also used to assess macrophage foam cell formation via Oil Red O staining and mitogen-activated protein kinase signaling via immunoblotting in the FcαRIR209L/FcRγ-expressing RAW264.7 macrophage cell line I3D. Results: Targeting of monovalent FcαRI induced inhibitory effects in the FcαRIR209L/FcRγApoE-/- mouse model of atherosclerosis by inhibiting macrophage infiltration. FcαRI targeting using the anti-FcαRI antibody also reduced mitogen-activated protein kinase signaling and foam cell formation, leading to decreased interleukin (IL)-1b and monocyte chemoattractant protein (MCP)-1. Conclusions: We demonstrated that targeting monovalent FcαRI suppresses atherosclerosis development. These findings can support the future clinical exploration of FcαRI targeting for atherosclerosis treatment.