Fasting-activated ventrolateral medulla neurons regulate T cell homing and suppress autoimmune disease in mice.

Dietary fasting markedly influences the distribution and function of immune cells and exerts potent immunosuppressive effects. However, the mechanisms through which fasting regulates immunity remain obscure. Here we report that catecholaminergic (CA) neurons in the ventrolateral medulla (VLM) are activated during fasting in mice, and we demonstrate that the activity of these CA neurons impacts the distribution of T cells and the development of autoimmune disease in an experimental autoimmune encephalomyelitis (EAE) model. Ablation of VLM CA neurons largely reversed fasting-mediated T cell redistribution. Activation of these neurons drove T cell homing to bone marrow in a CXCR4/CXCL12 axis-dependent manner, which may be mediated by a neural circuit that stimulates corticosterone secretion. Similar to fasting, the continuous activation of VLM CA neurons suppressed T cell activation, proliferation, differentiation and cytokine production in autoimmune mouse models and substantially alleviated disease symptoms. Collectively, our study demonstrates neuronal control of inflammation and T cell distribution, suggesting a neural mechanism underlying fasting-mediated immune regulation.

Water-stable hydrophilic metal organic framework composite for the recognition of N-glycopeptides during diabetes progression by mass spectrometry.

A hydrophilic Al-MOFs composite was prepared using cheap and available reagents in water via a suitable large-scale production, an economical and environment-friendly method for capturing N-glycopeptides. The prepared Al-MOFs composite with high hydrolytically stable and hydrophilic 1D channels exhibits an ultralow detection limit (0.5 fmol/µL), and excellent reusability (at least 10 cycles) in the capture of N-glycopeptides from standard bio-samples. Interestingly, the Al-MOFs composite also shows remarkable performance in practical applications, where 300 N-glycopeptides ascribed to 124 glycoproteins were identified in 1 µL human serum and were successfully applied in profiling the differences of N-glycopeptides during diabetes progression. Moreover, 12 specific glycoproteins used as biomarkers to accurately distinguish the progression of diabetes are identified. The present work provides a potential commercial method for large-scale glycoproteomics research in complex clinical samples while offering new guidance for the precise diagnosis of diabetes progression.

Characterization of Biodiesel and Diesel Combustion Particles: Chemical Composition, Lipid Metabolism, and Implications for Health and Environment.

Biodiesel, derived from alkyl esters of vegetable oils or animal fats, has gained prominence as a greener alternative to diesel due to its reduced particle mass. However, it remains debatable whether biodiesel exposure has more severe health issues than diesel. This study performed high-resolution mass spectrometry to examine the detailed particle chemical compositions and lipidomics analysis of human lung epithelial cells treated with emissions from biodiesel and diesel fuels. Results show the presence of the peak substances of CHO compounds in biodiesel combustion that contain a phthalate ester (PAEs) structure (e.g., n-amyl isoamyl phthalate and diisobutyl phthalate). PAEs have emerged as persistent organic pollutants across various environmental media and are known to possess endocrine-disrupting properties in the environment. We further observed that biodiesel prevents triglyceride storage compared to diesel and inhibits triglycerides from becoming phospholipids, particularly with increased phosphatidylglycerols (PGs) and phosphatidylethanolamines (PEs), which potentially could lead to a higher probability of cancer metastasis.

The early effects of sleeve gastrectomy on postprandial chylomicron triglycerides during the progression of type 2 diabetes.

BACKGROUND: It remains unclear whether early sleeve gastrectomy (SG) improves postprandial very-low-density lipoprotein (VLDL) as well as chylomicron triglycerides (TGs) in a weight-independent manner in patients with or without type 2 diabetes (DM). Herein we investigated the early effects of SG on postprandial VLDL and chylomicron kinetics. METHODS: A liquid meal test was performed before and after 1 week of SG. The plasma was collected for postprandial triglyceride-rich lipoprotein kinetics analyses, including VLDLs and chylomicrons, isolated by high-speed ultracentrifugation. Lipidomics and metabolomics were used to profile lipid and metabolite compositions of plasma and postprandial chylomicrons. De novo fatty acid synthesis in intestinal epithelial cells treated with chylomicron metabolites was examined using RT-PCR, immunoblotting, and free fatty acid measurement. RESULTS: We found that patients with DM had markedly higher VLDL TGs than patients without DM, and such an increase was still retained after SG. In contrast, SG significantly decreased postprandial chylomicron TGs, but surprisingly, the degree of the reduction in patients with DM was less prominent than in patients without DM, confirmed by untargeted lipidomics analysis. Moreover, 5 unique metabolites potentially linked to de novo fatty acid synthesis from the pathway analysis were discovered by further metabolomic analysis of postprandial chylomicrons from patients with DM who underwent SG and verified by In vitro intestinal epithelial cell culture experiments. CONCLUSIONS: SG in 1 week did not impact postprandial VLDL but decreased chylomicron TGs. Patients with DM keep higher postprandial chylomicron TG concentrations than patients without it after SG, potentially through some unique metabolites that increase intestinal fatty acid synthesis. These results implicate the timing for SG to reach lower intestinal fatty acid synthesis and postprandial chylomicron TG production is prior to the diagnosis of DM to potentially reduce cardiovascular risks.

A2AR-mediated lymphangiogenesis via VEGFR2 signaling prevents salt-sensitive hypertension.

AIMS: Excess dietary sodium intake and retention lead to hypertension. Impaired dermal lymphangiogenesis and lymphatic dysfunction-mediated sodium and fluid imbalance are pathological mechanisms. The adenosine A2A receptor (A2AR) is expressed in lymphatic endothelial cells (LECs), while the roles and mechanisms of LEC-A2AR in skin lymphangiogenesis during salt-induced hypertension are not clear. METHODS AND RESULTS: The expression of LEC-A2AR correlated with lymphatic vessel density in both high-salt diet (HSD)-induced hypertensive mice and hypertensive patients. Lymphatic endothelial cell-specific A2AR knockout mice fed HSD exhibited 17 ± 2% increase in blood pressure and 17 ± 3% increase in Na+ content associated with decreased lymphatic density (-19 ± 2%) compared with HSD-WT mice. A2AR activation by agonist CGS21680 increased lymphatic capillary density and decreased blood pressure in HSD-WT mice. Furthermore, this A2AR agonist activated MSK1 directly to promote VEGFR2 activation and endocytosis independently of VEGF as assessed by phosphoprotein profiling and immunoprecipitation assays in LECs. VEGFR2 kinase activity inhibitor fruquintinib or VEGFR2 knockout in LECs but not VEGF-neutralizing antibody bevacizumab suppressed A2AR activation-mediated decrease in blood pressure. Immunostaining revealed phosphorylated VEGFR2 and MSK1 expression in the LECs were positively correlated with skin lymphatic vessel density and A2AR level in hypertensive patients. CONCLUSION: The study highlights a novel A2AR-mediated VEGF-independent activation of VEGFR2 signaling in dermal lymphangiogenesis and sodium balance, which might be a potential therapeutic target in salt-sensitive hypertension.

Novel Three-Dimensional Hierarchical Porous Carbon Probe for the Discovery of N-Glycan Biomarkers and Early Hepatocellular Carcinoma Detection.

Due to the highly heterogeneous nature of hepatocellular carcinoma (HCC), the accurate diagnosis of HCC during the early phase of development is still a challenging task. Therefore, the further development of novel diagnostic methods by discovering new biomarkers is required to improve the rate of HCC diagnosis in the early phase. In this work, an oxygen-modified three-dimensional interconnected porous carbon probe is designed and fabricated to profile the differences of N-glycans in human serum from health controls (H) and patients with hepatic dysfunction (HD) and HCC for the discovery of new biomarkers with HCC development. Excitingly, we discovered that the expression levels of 12 serum N-glycans were gradually increased from H to patients with HD and eventually to patients with HCC. Moreover, two machine learning models established based on these 12 serum N-glycans reached a satisfactory accuracy for predicting HCC development where the receiver operating characteristic curve arrived above 0.95 for distinguishing healthy controls and patients with liver diseases (HD or HCC) and the ROC curve arrived at 0.85 for distinguishing HD and HCC. Our work not only developed a new method for the large-scale characterization of serum N-glycans but also provided valuable guidance for accurate and highly sensitive diagnosis of early liver cancer development in a non-invasive manner.

Naked-Eye Readout Distance Quantitative Lateral Flow Assay Based on the Permeability Changes of Enzyme-Catalyzed Hydrogelation.

Traditional lateral flow assay (LFA) is restricted to providing qualitative or semi-quantitative results and often requires special equipment for obtaining quantitative results. Herein, we proposed a naked-eye readout distance quantitative lateral flow assay based on the permeability changes in enzyme-catalyzed hydrogelation, which not only has the advantages of being simple, immediate, of high efficiency and low cost, and accurate in quantification but also avoids the use of special equipment. The developed LFA method includes three principal components of a nitrocellulose (NC) membrane containing a control line (C line) loading goat anti-rabbit (GAR) antibodies and a test line (T line) loading specific antibodies, alginate-tyramine conjugates forming a hydrogel in the presence of hydrogen peroxide (H2O2) and horseradish peroxidase (HRP), and the HRP-AuNPs-Ab probe only labeling targets captured on the T line. Hemoglobin A1c (HbA1c) was chosen as a representative example to demonstrate the feasibility of our method. Under the optimal conditions, the developed LFA method shows excellent performance in standard samples and real human blood samples where the results of real human blood samples show a high linear correlation with the clinical data obtained by ion exchange chromatography (R2 = 0.9929) and the margin of recovery is only 3.8%. All results demonstrated that our developed LFA method not only has enormous potential in the quantitative detection of HbA1c in clinical complex samples but also can serve as a versatile method for highly efficient detection of other target biomolecules due to the fungibility of antibodies.

Network analysis of large-scale ImmGen and Tabula Muris datasets highlights metabolic diversity of tissue mononuclear phagocytes.

The diversity of mononuclear phagocyte (MNP) subpopulations across tissues is one of the key physiological characteristics of the immune system. Here, we focus on understanding the metabolic variability of MNPs through metabolic network analysis applied to three large-scale transcriptional datasets: we introduce (1) an ImmGen MNP open-source dataset of 337 samples across 26 tissues; (2) a myeloid subset of ImmGen Phase I dataset (202 MNP samples); and (3) a myeloid mouse single-cell RNA sequencing (scRNA-seq) dataset (51,364 cells) assembled based on Tabula Muris Senis. To analyze such large-scale datasets, we develop a network-based computational approach, genes and metabolites (GAM) clustering, for unbiased identification of the key metabolic subnetworks based on transcriptional profiles. We define 9 metabolic subnetworks that encapsulate the metabolic differences within MNP from 38 different tissues. Obtained modules reveal that cholesterol synthesis appears particularly active within the migratory dendritic cells, while glutathione synthesis is essential for cysteinyl leukotriene production by peritoneal and lung macrophages.

Facile preparation of a novel chitosan-derived porous graphitized carbon biomaterial for highly efficient capture of N-glycans.

The comprehensive characterization of N-glycans is of significant importance for the discovery of potential biomarkers and the diagnosis and therapy of diseases. Herein, we designed and fabricated a porous graphitized carbon biomaterial (CS-900-1C) using cheap and available chitosan as the carbon source via a facile pyrolysis process and a post-oxidation strategy for the effective capture of N-glycans. Thanks to its large surface area (2846 m2 g-1), high graphitization degree, suitable oxidation degree and unique porous structure, the CS-900-1C biomaterial exhibits an ultralow detection limit (1 ng µL-1), an excellent size-exclusion effect (OVA digest : BSA protein : OVA protein, 1 : 1000 : 1000, w/w/w) and satisfactory reusability (at least 8 cycles) in the capture of standard N-glycans. Moreover, CS-900-1C has successfully been applied in profiling the difference of N-glycans during diabetes progression (obesity, impaired glucose tolerance, diabetes patients and healthy control) where we discovered that the expression levels of five N-glycans show a gradually increasing trend as diabetes progresses. Remarkably, the five specific N-glycans could be considered as biomarkers to accurately diagnose the progression of diabetes. Our work not only developed a novel porous graphitized carbon biomaterial for the large-scale characterization of N-glycans but also provided new guidance for the precise therapy of diabetes.

Facile Preparation of Three-Dimensional Wafer with Interconnected Porous Structure for High-Performance Capture and Nondestructive Release of Circulating Tumor Cells.

Efficient isolation and downstream bioinformation analysis of circulating tumor cells (CTCs) in whole blood contribute to the early diagnosis of cancer and investigation of cancer metastasis. However, the separation and release of CTCs remain a great challenge due to the extreme rarity of CTCs and severe interference from other cells in complex clinical samples. Herein, we developed a low-cost and easy-to-fabricate aptamer-functionalized wafer with a three-dimensional (3D) interconnected porous structure by grafting polydopamine (PDA), poly(ethylene glycol) (PEG), and aptamer in sequence (Ni@PDA-PEG-Apt) for the capture and release of CTCs. The Ni@PDA-PEG-Apt wafer integrated the features of Ni foam with a 3D interconnected porous structure offering enough tunnels for cells to flow through and enhancing aptamer-cell contact frequency, the spacer PEG with flexible and high hydrophilic property increasing anti-interference ability and providing the wafer with more binding sites for aptamer, which result in an enhanced capture specificity and efficiency for CTCs. Because of these advantages, the Ni@PDA-PEG-Apt wafer achieved a high capture efficiency of 78.25%. The captured cancer cells were mildly released by endonuclease with up to 61.85% efficiency and good proliferation. Furthermore, tumor cells were injected into mice and experienced circulation in vivo. In blood samples after circulation, 65% of target tumor cells can be efficiently captured by the wafer, followed by released and recultured cells with high viability. Further downstream metabolomics analysis showed that target cancer cells remained with high biological activity and can be well separated from MCF-10A cells based on metabolic profiles by the PCA analysis, indicating the great potential of our strategy for further research on the progression of cancer metastasis. Notably, not only is the wafer cheap with a cost of only 3.58 U.S. dollars and easily prepared by environmental-friendly reagents but also the process of capturing and releasing tumor cells can be completed within an hour, which is beneficial for large-scale clinical use in the future.

A novel hydrophilic MOFs-303-functionalized magnetic probe for the highly efficient analysis of N-linked glycopeptides.

The effective analysis of glycoproteomics in clinical complex samples is of vital importance for the diagnosis and therapy of diseases. In this study, a hydrophilic MOFs-303-functionalized magnetic probe (GO@Fe3O4@MOF-303) is designed and fabricated to profile N-linked glycopeptides. Owing to its strong magnetic property, large surface area (845 m2 g-1), excellent hydrophilicity and suitable porous structure, the GO@Fe3O4@MOF-303 probe exhibits an ultralow detection limit (0.1 fmol µL-1), perfect size-exclusion effect (HRP digests/BSA protein/HRP protein, 1 : 1000 : 1000, w/w/w), a high binding capacity (200 mg g-1) and excellent reusability in the capture of standard N-linked glycopeptides. More excitingly, the GO@Fe3O4@MOF-303 probe also shows remarkable performance in practical applications, where 274 N-linked glycopeptides from 101 glycoproteins were identified in total for healthy controls, while a total of 265 N-linked glycopeptides from 102 glycoproteins were identified in serum (1 µL) with hepatocellular carcinoma (HCC). In addition, we discovered 4 up-regulated and 19 down-regulated serum glycoproteins in HCC patients by the hierarchical clustering heatmap. All results demonstrated that the reusable GO@Fe3O4@MOF-303 probe has great potential in profiling different N-linked glycopeptides in complex clinical samples. This study not only developed a novel probe for the highly effective capture of N-linked glycopeptides but also contributed to further understanding the mechanism of HCC and provides guidance for the development of novel clinical diagnostic methods.

Enterically derived high-density lipoprotein restrains liver injury through the portal vein.

The biogenesis of high-density lipoprotein (HDL) requires apoA1 and the cholesterol transporter ABCA1. Although the liver generates most of the HDL in the blood, HDL synthesis also occurs in the small intestine. Here, we show that intestine-derived HDL traverses the portal vein in the HDL3 subspecies form, in complex with lipopolysaccharide (LPS)-binding protein (LBP). HDL3, but not HDL2 or low-density lipoprotein, prevented LPS binding to and inflammatory activation of liver macrophages and instead supported extracellular inactivation of LPS. In mouse models involving surgical, dietary, or alcoholic intestinal insult, loss of intestine-derived HDL worsened liver injury, whereas outcomes were improved by therapeutics that elevated and depended upon raising intestinal HDL. Thus, protection of the liver from injury in response to gut-derived LPS is a major function of intestinally synthesized HDL.

CC Chemokine Receptor 5 Targeted Nanoparticles Imaging the Progression and Regression of Atherosclerosis Using Positron Emission Tomography/Computed Tomography.

Chemokines and chemokine receptors play an important role in the initiation and progression of atherosclerosis by mediating the trafficking of inflammatory cells. Chemokine receptor 5 (CCR5) has major implications in promoting the development of plaques to advanced stage and related vulnerability. CCR5 antagonist has demonstrated the effective inhibition of atherosclerotic progression in mice, making it a potential biomarker for atherosclerosis management. To accurately determine CCR5 in vivo, we synthesized CCR5 targeted Comb nanoparticles through a modular design and construction strategy with control over the physiochemical properties and functionalization of CCR5 targeting peptide d-Ala-peptide T-amide (DAPTA-Comb). In vivo pharmacokinetic evaluation through 64Cu radiolabeling showed extended blood circulation of 64Cu-DAPTA-Combs conjugated with 10%, 25%, and 40% DAPTA. The different organ distribution profiles of the three nanoparticles demonstrated the effect of DAPTA on not only physicochemical properties but also targeting efficiency. In vivo positron emission tomography/computed tomography (PET/CT) imaging in an apolipoprotein E knockout mouse atherosclerosis model (ApoE-/-) showed that the three 64Cu-DAPTA-Combs could sensitively and specifically detect CCR5 along the progression of atherosclerotic lesions. In an ApoE-encoding adenoviral vector (AAV) induced plaque regression ApoE-/- mouse model, decreased monocyte recruitment, CD68+ macrophages, CCR5 expression, and plaque size were all associated with reduced PET signals, which not only further confirmed the targeting efficiency of 64Cu-DAPTA-Combs but also highlighted the potential of these targeted nanoparticles for atherosclerosis imaging. Moreover, the up-regulation of CCR5 and colocalization with CD68+ macrophages in the necrotic core of ex vivo human plaque specimens warrant further investigation for atherosclerosis prognosis.

CXCR4-Binding Positron Emission Tomography Tracers Link Monocyte Recruitment and Endothelial Injury in Murine Atherosclerosis.

OBJECTIVE: vMIP-II (viral macrophage inflammatory protein 2)/vCCL2 (viral chemotactic cytokine ligand 2) binds to multiple chemokine receptors, and vMIP-II-based positron emission tomography tracer (64Cu-DOTA-vMIP-II: vMIP-II tracer) accumulates at atherosclerotic lesions in mice. Given that it would be expected to react with multiple chemokine receptors on monocytes and macrophages, we wondered if its accumulation in atherosclerosis lesion-bearing mice might correlate with overall macrophage burden or, alternatively, the pace of monocyte recruitment. Approach and Results: We employed a mouse model of atherosclerosis regression involving adenoassociated virus 8 vector encoding murine Apoe (AAV-mApoE) treatment of Apoe-/- mice where the pace of monocyte recruitment slows before macrophage burden subsequently declines. Accumulation of 64Cu-DOTA-vMIP-II at Apoe-/- plaque sites was strong but declined with AAV-mApoE-induced decline in monocyte recruitment, before macrophage burden reduced. Monocyte depletion indicated that monocytes and macrophages themselves were not the only target of the 64Cu-DOTA-vMIP-II tracer. Using fluorescence-tagged vMIP-II tracer, competitive receptor blocking with CXCR4 antagonists, endothelial-specific Cre-mediated deletion of CXCR4, CXCR4-specific tracer 64Cu-DOTA-FC131, and CXCR4 staining during disease progression and regression, we show endothelial cell expression of CXCR4 is a key target of 64Cu-DOTA-vMIP-II imaging. Expression of CXCR4 was low in nonplaque areas but strongly detected on endothelium of progressing plaques, especially on proliferating endothelium, where vascular permeability was increased and monocyte recruitment was the strongest. CONCLUSIONS: Endothelial injury status of plaques is marked by CXCR4 expression and this injury correlates with the tendency of such plaques to recruit monocytes. Furthermore, our findings suggest positron emission tomography tracers that mark CXCR4 can be used translationally to monitor the state of plaque injury and monocyte recruitment.

Analysis of single-cell RNAseq identifies transitional states of T cells associated with hepatocellular carcinoma.

BACKGROUND: Exhausted T cells and regulatory T cells (Tregs) comprise diverse subsets of tumor immunosuppressive microenvironment that play key roles in tumor progress. Understanding subset diversity in T cells is a critical question for developing cancer immunotherapy. METHODS: A total of 235 specimens from surgical resections of hepatocellular carcinoma (HCC) patients were examined for infiltration of exhausted T cell (Tex) in tumor and adjacent tissue. We conducted deep single-cell targeted immune profiling on CD3+ cells collected from tumor tissues, adjacent normal tissues (ANTs) and peripheral blood of HCC patients. Total 10 cell clusters were identified with distinct distributions and characteristics. RESULTS: We observed transitional differentiation of exhausted CD8+ T cells and Tregs increasingly enriched in tumor tissue. The accumulation and location of Tex were related to the differences in the long-term clinical outcome of HCC. Furthermore, data of single-cell RNA-seq showed that (1) cells transforming from effector CD8+ T cells to exhausted CD8+ T cells simultaneously expressed upregulated effector molecules and inhibitory receptors, (2) indicated alteration of gene expression related to stress response and cell cycle at early exhaustion stage, and (3) immunosuppressive Treg had profound activation in comparison to resting Tregs. CONCLUSIONS: T cell exhaustion is a progressive process, and the gene-expression profiling displayed T cell exhaustion and anergy are different. Accordingly, it is possible that functional exhaustion is caused by the combination effects of passive defects and overactivation in stress response. The results help to understand the dynamic framework of T cells function in cancer which is important for designing rational cancer immunotherapies.

Roles of Reconstituted High-Density Lipoprotein Nanoparticles in Cardiovascular Disease: A New Paradigm for Drug Discovery.

Epidemiological results revealed that there is an inverse correlation between high-density lipoprotein (HDL) cholesterol levels and risks of atherosclerotic cardiovascular disease (ASCVD). Mounting evidence supports that HDLs are atheroprotective, therefore, many therapeutic approaches have been developed to increase HDL cholesterol (HDL-C) levels. Nevertheless, HDL-raising therapies, such as cholesteryl ester transfer protein (CETP) inhibitors, failed to ameliorate cardiovascular outcomes in clinical trials, thereby casting doubt on the treatment of cardiovascular disease (CVD) by increasing HDL-C levels. Therefore, HDL-targeted interventional studies were shifted to increasing the number of HDL particles capable of promoting ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux. One such approach was the development of reconstituted HDL (rHDL) particles that promote ABCA1-mediated cholesterol efflux from lipid-enriched macrophages. Here, we explore the manipulation of rHDL nanoparticles as a strategy for the treatment of CVD. In addition, we discuss technological capabilities and the challenge of relating preclinical in vivo mice research to clinical studies. Finally, by drawing lessons from developing rHDL nanoparticles, we also incorporate the viabilities and advantages of the development of a molecular imaging probe with HDL nanoparticles when applied to ASCVD, as well as gaps in technology and knowledge required for putting the HDL-targeted therapeutics into full gear.

Myeloid Acat1/Soat1 KO attenuates pro-inflammatory responses in macrophages and protects against atherosclerosis in a model of advanced lesions.

Cholesterol esters are a key ingredient of foamy cells in atherosclerotic lesions; their formation is catalyzed by two enzymes: acyl-CoA:cholesterol acyltransferases (ACATs; also called sterol O-acyltransferases, or SOATs) ACAT1 and ACAT2. ACAT1 is present in all body cells and is the major isoenzyme in macrophages. Whether blocking ACAT1 benefits atherosclerosis has been under debate for more than a decade. Previously, our laboratory developed a myeloid-specific Acat1 knockout (KO) mouse (Acat1-M/-M), devoid of ACAT1 only in macrophages, microglia, and neutrophils. In previous work using the ApoE KO (ApoE-/-) mouse model for early lesions, Acat1-M/-M significantly reduced lesion macrophage content and suppressed atherosclerosis progression. In advanced lesions, cholesterol crystals become a prominent feature. Here we evaluated the effects of Acat1-M/-M in the ApoE KO mouse model for more advanced lesions and found that mice lacking myeloid Acat1 had significantly reduced lesion cholesterol crystal contents. Acat1-M/-M also significantly reduced lesion size and macrophage content without increasing apoptotic cell death. Cell culture studies showed that inhibiting ACAT1 in macrophages caused cells to produce less proinflammatory responses upon cholesterol loading by acetyl low-density lipoprotein. In advanced lesions, Acat1-M/-M reduced but did not eliminate foamy cells. In advanced plaques isolated from ApoE-/- mice, immunostainings showed that both ACAT1 and ACAT2 are present. In cell culture, both enzymes are present in macrophages and smooth muscle cells and contribute to cholesterol ester biosynthesis. Overall, our results support the notion that targeting ACAT1 or targeting both ACAT1 and ACAT2 in macrophages is a novel strategy to treat advanced lesions.

Cytokine Circuits in Cardiovascular Disease.

Arterial inflammation is a hallmark of atherosclerosis, and appropriate management of this inflammation represents a major unmet therapeutic need for cardiovascular disease patients. Here, we review the diverse contributions of immune cells to atherosclerosis, the mechanisms of immune cell activation in this context, and the cytokine circuits that underlie disease progression. We discuss the recent application of these insights in the form of immunotherapy to treat cardiovascular disease and highlight how studies on the cardiovascular co-morbidity that arises in autoimmunity might reveal additional roles for cytokines in atherosclerosis. Currently, data point to interleukin-1ß (IL-1ß), tumor necrosis factor (TNF), and IL-17 as cytokines that, at least in some settings, are effective targets to reduce cardiovascular disease progression.

Interleukin-17 Drives Interstitial Entrapment of Tissue Lipoproteins in Experimental Psoriasis.

Lipoproteins trapped in arteries drive atherosclerosis. Extravascular low-density lipoprotein undergoes receptor uptake, whereas high-density lipoprotein (HDL) interacts with cells to acquire cholesterol and then recirculates to plasma. We developed photoactivatable apoA-I to understand how HDL passage through tissue is regulated. We focused on skin and arteries of healthy mice versus those with psoriasis, which carries cardiovascular risk in man. Our findings suggest that psoriasis-affected skin lesions program interleukin-17-producing T cells in draining lymph nodes to home to distal skin and later to arteries. There, these cells mediate thickening of the collagenous matrix, such that larger molecules including lipoproteins become entrapped. HDL transit was rescued by depleting CD4+ T cells, neutralizing interleukin-17, or inhibiting lysyl oxidase that crosslinks collagen. Experimental psoriasis also increased vascular stiffness and atherosclerosis via this common pathway. Thus, interleukin-17 can reduce lipoprotein trafficking and increase vascular stiffness by, at least in part, remodeling collagen.