Lipoprotein Particles in Cerebrospinal Fluid.

The brain is the most lipid-rich organ in the body, and the intricate interplay between lipid metabolism and pathologies associated with neurodegenerative disorders is being increasingly recognized. The brain is bathed in cerebrospinal fluid (CSF), which, like plasma, contains lipid-protein complexes called lipoproteins that are responsible for extracellular lipid transport. Multiple CSF lipoprotein populations exist, some of which are produced de novo in the central nervous system and others that appear to be generated from protein constituents that are produced in the periphery. These CSF lipoproteins are thought to play key roles in maintaining lipid homeostasis in the central nervous system, while little else is known due to their limited accessibility and their low abundance in CSF. Recent work has provided new insights into the compositional complexity of CSF lipoprotein families and their metabolism in cerebral circulation. The purpose of this review is to summarize our current state of knowledge on the composition, origin, and metabolism of CSF lipoproteins.

Chest computer tomography is safe without additional interrogation or monitoring for modern cardiac implantable electrical devices.

INTRODUCTION: Whether diagnostic computed tomography (CT) scans to cardiac implantable electronic devices (CIED) is safe in recent models remains unknown. METHODS: A two-centers observational study. Over 14 years, consecutive 2362 chest CT scans (1666 pacemakers [PMs], 145 cardiac resynchronization therapy PM, 316 implantable cardioverter-defibrillator, and 233 cardiac resynchronization therapy defibrillator) were interrogated and monitored upon imaging. RESULTS: Electromagnetic interference occurred only in a few old models: InSync 8040 (n = 14), InSync III Marquis (n = 1), and Kappa (n = 4), which resulted no adverse events. CONCLUSION: CIEDs, especially recent ones, are confirmed safe on chest CT.

Oxidation of methionine residues in human apolipoprotein A-I generates a potent pro-inflammatory molecule.

Amyloid deposits of apolipoprotein A-I (apoA-I) and inflammation are common in atherosclerotic arteries. In this study, we investigated the interplay between oxidation of apoA-I methionine residues (Met(O)-ApoA-I), a known amyloidogenic modification of apoA-I, and the inflammatory response of immune cells. Soluble pre-fibrillar Met(O)-ApoA-I, but not apoA-I, induced intracellular accumulation of pro-interleukin (IL)-1ß and secretion of the pro-inflammatory cytokines tumor necrosis factor α (TNFα) and IL-6 in mouse bone marrow-derived macrophages (BMDMs) and human primary monocytes. Additionally, secretion of mature IL-1ß was also activated in human monocytes. The pro-inflammatory activity of Met(O)-ApoA-I was Toll-like receptor 4 (TLR4)-dependent and CD36-independent and was solely determined by oxidation of apoA-I methionine residues, in particular Met-86 and Met-148. In contrast, amyloid fibrils or reconstituted high-density lipoproteins (HDLs) generated from Met(O)-ApoA-I did not induce cytokine production in BMDMs. Although lipid-free Met(O)-ApoA-I remained functional in extracting lipids from cells and generating HDL, it gained strong pro-inflammatory properties that may aggravate local inflammation in the arteries and atherosclerosis. Our study indicates that oxidation of apoA-I methionine residues produces a potent danger-associated molecular pattern capable of stimulating pro-inflammatory cytokine secretion at levels similar to those induced by known pathogen-associated molecular patterns, such as lipopolysaccharide.

Clinical application of a new ternary polymer, SEC-1 coat™, for pediatric cardiopulmonary bypass circuits: a prospective randomized pilot study.

OBJECTIVE: The use of biocompatible materials to reduce the systemic activation of inflammation and coagulation pathways is expanding rapidly. However, there have been few clinical studies of biocompatible circuits for pediatric cardiopulmonary bypass. This pilot study aimed to preliminarily evaluate the biocompatibility of SEC-1 coat™ (SEC) for cardiopulmonary bypass circuits in pediatric cardiac surgery. METHODS: Twenty infants undergoing cardiac surgery for isolated ventricular septal defects at Kobe Children's Hospital were assigned randomly to an SEC-coated (SEC group, n = 10) or heparin-coated (control group, n = 10) circuit. Perioperative data and the following markers were prospectively analyzed: platelet counts and interleukin-6, interleukin-8, C3a, ß-thromboglobulin, and thrombin-antithrombin complex levels. RESULTS: Neither patient characteristics nor postoperative clinical outcomes differed significantly between the SEC and control groups. Platelet counts markedly decreased during cardiopulmonary bypass in both groups, but were significantly better preserved in the SEC group. Fewer patients needed postoperative platelet transfusions in the SEC group. After cardiopulmonary bypass termination, serum levels of ß-thromboglobulin and thrombin-antithrombin complex were significantly lower in the SEC than in the control group. Although the differences were not statistically significant, serum levels of interleukin-6, interleukin-8, and C3a had a tendency toward being lower in the SEC group, with good preservation of leukocyte counts, fibrinogen, and antithrombin III. CONCLUSION: SEC-1 coat™ for cardiopulmonary bypass circuits have good biocompatibility with regard to platelet preservation and in terms of attenuating inflammatory reaction or coagulation activation during pediatric cardiac surgery. It can be beneficial in pediatric as well as adult cardiac surgery.

Probucol-Oxidized Products, Spiroquinone and Diphenoquinone, Promote Reverse Cholesterol Transport in Mice.

OBJECTIVE: Oxidized products of probucol, spiroquinone and diphenoquinone, were shown to increase cell cholesterol release and plasma high-density lipoprotein (HDL) by inhibiting degradation of ATP-binding cassette transporter A1. We investigated whether these compounds enhance reverse cholesterol transport in mice. APPROACH AND RESULTS: Spiroquinone and diphenoquinone increased ATP-binding cassette transporter A1 protein (2.8- and 2.6-fold, respectively, P<0.01) and apolipoprotein A-I-mediated cholesterol release (1.4- and 1.4-fold, P<0.01 and P<0.05, respectively) in RAW264.7 cells. However, diphenoquinone, but not spiroquinone, enhanced cholesterol efflux to HDL (+12%, P<0.05), whereas both increased ATP-binding cassette transporter G1 protein, by 1.8- and 1.6-fold, respectively. When given orally to mice, both compounds significantly increased plasma HDL-cholesterol, by 19% and 20%, respectively (P<0.05), accompanied by an increase in hepatic and macrophage ATP-binding cassette transporter A1 but not ATP-binding cassette transporter G1. We next evaluated in vivo reverse cholesterol transport by injecting RAW264.7 cells labeled with (3)H-cholesterol intraperitoneally into mice. Both spiroquinone and diphenoquinone increased fecal excretion of the macrophage-derived (3)H-tracer, by 25% and 28% (P<0.01 and P<0.05), respectively. spiroquinone/diphenoquinone did not affect fecal excretion of HDL-derived (3)H-cholesterol, implying that macrophage-to-plasma was the most important step in spiroquinone/diphenoquinone-mediated promotion of in vivo reverse cholesterol transport. Finally, spiroquinone significantly reduced aortic atherosclerosis in apolipoprotein E null mice when compared with the vehicle. CONCLUSIONS: Spiroquinone and diphenoquinone increase functional ATP-binding cassette transporter A1 in both the macrophages and the liver, elevate plasma HDL-cholesterol, and promote overall reverse cholesterol transport in vivo. These compounds are promising as therapeutic reagents against atherosclerosis.

Interleukin-1ß is associated with coronary endothelial dysfunction in patients with mTOR-inhibitor-eluting stent implantation.

Implantation of mammalian target of rapamycin (mTOR)-inhibitor drug-eluting stents (DESs) impairs coronary endothelial function. There are no known non-invasive biomarkers of coronary endothelial dysfunction. We aimed to assess the association between serum interleukin-1beta (IL-1ß) and coronary endothelial dysfunction in patients with mTOR-inhibitor DES implantation and to investigate the association between the mTOR pathway and IL-1ß. We enrolled 35 patients who had implanted DESs for coronary artery disease. At a 10-month follow-up, peripheral venous blood samples were collected to measure IL-1ß levels. Coronary endothelial dysfunction was evaluated by intracoronary infusion of incremental doses of acetylcholine. Serum IL-1ß levels were significantly associated with the magnitude of vasoconstriction to acetylcholine at the segment distal (P < 0.05) but not proximal to the stent. Serum IL-1ß levels were positively correlated with stent length (P < 0.05). To examine the direct effects of mTOR inhibition on IL-1ß release, sirolimus was incubated in cultured human umbilical vein endothelial cells (HUVECs) or coronary artery smooth muscle cells (CASMCs). Sirolimus directly increased IL-1ß mRNA expression (P < 0.01) and enhanced IL-1ß release into the culture media (P < 0.01) in CASMCs, but not in HUVECs. Inhibition of mTOR triggers IL-1ß release through transcriptional activation in CASMCs. Serum IL-1ß levels are a potential biomarker for mTOR-inhibitor DES-associated coronary endothelial dysfunction.

ApoA-I/A-II-HDL positively associates with apoB-lipoproteins as a potential atherogenic indicator.

BACKGROUND: We recently reported distinct nature of high-density lipoproteins (HDL) subgroup particles with apolipoprotein (apo) A-I but not apoA-II (LpAI) and HDL having both (LpAI:AII) based on the data from 314 Japanese. While plasma HDL level almost exclusively depends on concentration of LpAI having 3 to 4 apoA-I molecules, LpAI:AII appeared with almost constant concentration regardless of plasma HDL levels having stable structure with two apoA-I and one disulfide-dimeric apoA-II molecules (Sci. Rep. 6; 31,532, 2016). The aim of this study is further characterization of LpAI:AII with respect to its role in atherogenesis. METHODS: Association of LpAI, LpAI:AII and other HDL parameters with apoB-lipoprotein parameters was analyzed among the cohort data above. RESULTS: ApoA-I in LpAI negatively correlated with the apoB-lipoprotein parameters such as apoB, triglyceride, nonHDL-cholesterol, and nonHDL-cholesterol + triglyceride, which are apparently reflected in the relations of the total HDL parameters to apoB-lipoproteins. In contrast, apoA-I in LpAI:AII and apoA-II positively correlated to the apoB-lipoprotein parameters even within their small range of variation. These relationships are independent of sex, but may slightly be influenced by the activity-related CETP mutations. CONCLUSIONS: The study suggested that LpAI:AII is an atherogenic indicator rather than antiatherogenic. These sub-fractions of HDL are to be evaluated separately for estimating atherogenic risk of the patients.

ABCA1-dependent sterol release: sterol molecule specificity and potential membrane domain for HDL biogenesis.

Mammalian cells synthesize various sterol molecules, including the C30 sterol, lanosterol, as cholesterol precursors in the endoplasmic reticulum. The build-up of precursor sterols, including lanosterol, displays cellular toxicity. Precursor sterols are found in plasma HDL. How these structurally different sterols are released from cells is poorly understood. Here, we show that newly synthesized precursor sterols arriving at the plasma membrane (PM) are removed by extracellular apoA-I in a manner dependent on ABCA1, a key macromolecule for HDL biogenesis. Analysis of sterol molecules by GC-MS and tracing the fate of radiolabeled acetate-derived sterols in normal and mutant Niemann-Pick type C cells reveal that ABCA1 prefers newly synthesized sterols, especially lanosterol, as the substrates before they are internalized from the PM. We also show that ABCA1 resides in a cholesterol-rich membrane domain resistant to the mild detergent, Brij 98. Blocking ACAT activity increases the cholesterol contents of this domain. Newly synthesized C29/C30 sterols are transiently enriched within this domain, but rapidly disappear from this domain with a half-life of less than 1 h. Our work shows that substantial amounts of precursor sterols are transported to a certain PM domain and are removed by the ABCA1-dependent pathway.

ATP-binding cassette transporter A7 (ABCA7) loss of function alters Alzheimer amyloid processing.

The ATP-binding cassette transporter A7 (ABCA7) has been identified as a susceptibility factor of late onset Alzheimer disease in genome-wide association studies. ABCA7 has been shown to mediate phagocytosis and affect membrane trafficking. The current study examined the impact of ABCA7 loss of function on amyloid precursor protein (APP) processing and generation of amyloid-ß (Aß). Suppression of endogenous ABCA7 in several different cell lines resulted in increased ß-secretase cleavage and elevated Aß. ABCA7 knock-out mice displayed an increased production of endogenous murine amyloid Aß42 species. Crossing ABCA7-deficient animals to an APP transgenic model resulted in significant increases in the soluble Aß as compared with mice expressing normal levels of ABCA7. Only modest changes in the amount of insoluble Aß and amyloid plaque densities were observed once the amyloid pathology was well developed, whereas Aß deposition was enhanced in younger animals. In vitro studies indicated a more rapid endocytosis of APP in ABCA7 knock-out cells that is mechanistically consistent with the increased Aß production. These in vitro and in vivo findings indicate a direct role of ABCA7 in amyloid processing that may be associated with its primary biological function to regulate endocytic pathways. Several potential loss-of-function ABCA7 mutations and deletions linked to Alzheimer disease that in some instances have a greater impact than apoE allelic variants have recently been identified. A reduction in ABCA7 expression or loss of function would be predicted to increase amyloid production and that may be a contributing factor in the associated Alzheimer disease susceptibility.

Deficiency in the Lipid Exporter ABCA1 Impairs Retrograde Sterol Movement and Disrupts Sterol Sensing at the Endoplasmic Reticulum.

Cellular cholesterol homeostasis involves sterol sensing at the endoplasmic reticulum (ER) and sterol export from the plasma membrane (PM). Sterol sensing at the ER requires efficient sterol delivery from the PM; however, the macromolecules that facilitate retrograde sterol transport at the PM have not been identified. ATP-binding cassette transporter A1 (ABCA1) mediates cholesterol and phospholipid export to apolipoprotein A-I for the assembly of high density lipoprotein (HDL). Mutations in ABCA1 cause Tangier disease, a familial HDL deficiency. Several lines of clinical and experimental evidence suggest a second function of ABCA1 in cellular cholesterol homeostasis in addition to mediating cholesterol efflux. Here, we report the unexpected finding that ABCA1 also plays a key role in facilitating retrograde sterol transport from the PM to the ER for sterol sensing. Deficiency in ABCA1 delays sterol esterification at the ER and activates the SREBP-2 cleavage pathway. The intrinsic ATPase activity in ABCA1 is required to facilitate retrograde sterol transport. ABCA1 deficiency causes alternation of PM composition and hampers a clathrin-independent endocytic activity that is required for ER sterol sensing. Our finding identifies ABCA1 as a key macromolecule facilitating bidirectional sterol movement at the PM and shows that ABCA1 controls retrograde sterol transport by modulating a certain clathrin-independent endocytic process.

Clinical equivalency of cardiopulmonary bypass and extracorporeal membrane oxygenation support for pediatric tracheal reconstruction.

OBJECTIVE: Pediatric surgery for congenital tracheal stenosis continues to be a therapeutic challenge, and it often requires cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO) for intra-operative extracorporeal cardiorespiratory support. The purpose of this study was to compare the peri-operative outcomes of CPB with ECMO in pediatric tracheal reconstruction. METHODS: Forty-three consecutive patients who underwent tracheal reconstruction without intra-cardiac repair for congenital tracheal stenosis at Kobe Children's Hospital between January 2000 and August 2012 were enrolled in this retrospective study. They were divided into two groups according to intra-operative extracorporeal cardiopulmonary support [CPB (n = 17) or ECMO (n = 26)]. Peri-operative variables were compared between the two groups. RESULTS: The CPB and ECMO groups had similar patient and operative characteristics. However, the CPB group required larger priming volume and higher doses of total heparin injection. Although the ECMO group exhibited less peri-operative bleeding and lower red blood cell requirement, there were no statistically significant differences between the two groups. Compared to the ECMO group, patients in the CPB group had significantly less positive fluid balance during surgery and in the first 24 h after surgery, and exhibited a trend towards higher ratios of PO2 to the fraction of inspired oxygen and lower PCO2 at the time of ICU admission and on post-operative day 1. CONCLUSIONS: Pediatric tracheal reconstruction should be performed with intra-operative CPB or ECMO, after considering the advantages of utilizing each extracorporeal cardiorespiratory support type according to the patient's specific condition and situation.

A potential screening factor for accumulation of cholesteyl ester transfer protein deficiency in East Asia: Schistosoma japonicum.

Cholesteryl ester transfer protein (CETP)-deficiency manifests a unique plasma lipoprotein profile without other apparent symptoms. It is highly common in East Asia while rather rare anywhere else. A potential environmental screening factor(s) may therefore contribute to this eccentric distribution, such as its selective advantage against a regional illness, most likely an infectious disease, in relation to plasma lipoproteins. Blood flukes use the host plasma lipoproteins as nutrient sources through the lipoprotein receptor-like systems. Its Asian-specific species, Schistosoma (S) japonicum, which has been endemic in East Asia, takes up cholesteryl ester (CE) from high-density lipoprotein (HDL) for the embryonation of their eggs to miracidia, a critical step of the hepatic pathogenesis of this parasite, but poorly from HDL of CETP-deficiency. CD36-related protein (CD36RP) was cloned from the adults and the eggs of S. japonicum, with 1880-bp encoding 506 amino-acid residues exhibiting the CD36 domains and two transmembrane regions. Its extracellular domain selectively bound human HDL but neither LDL nor CETP-deficiency HDL, and the antibody against the extracellular domain suppressed the selective HDL-CE uptake and embryonation of the eggs. When infected with S. japonicum, wild-type mice developed less hepatic granulomatosis than CETP-transgenic mice by the ectopic egg embryonation. CD36RP is thus a candidate receptor of S. japonicum to facilitate uptake of HDL-CE necessary for egg embryonation. Abnormal HDL caused by CETP-deficiency retards this process and thereby protects the patients from development of hepatic lesions. S. japonicum infection is a potential screening factor for high prevalence of CETP deficiency in East Asia.

Apolipoprotein A-I induces tubulin phosphorylation in association with cholesterol release in fetal rat astrocytes.

We previously identified cytosolic lipid-protein particles (CLPP) having size and density of HDL in rat astrocytes, to which apoA-I induces translocation of cholesterol, caveolin-1 and protein kinase Cα (PKCα) following its association with microtubules prior to cholesterol release/biogenesis of HDL (JBC 277: 7929, 2002; JLR 45: 2269, 2004). To further understand the physiological relevance of these findings, we investigated the CLPP/microtubule association and its role in intracellular cholesterol trafficking by using a technique of reconstituted microtubule-like filaments (rMT) in rat astrocyte cytosol. When the cells were pretreated with apoA-I, α-tubulin as a 52-kDa protein in rMT was found phosphorylated while α-tubulin in a soluble monomeric form was little phosphorylated. The phosphorylation took place coincidentally to apoA-I-induced association with rMT of CLPP, a complex containing PKCα, and was suppressed by a PKC inhibitor, Bis indolylmaleimide 1 (BIM). α-Tubulin dissociated from CLPP when phosphorylated, and it poorly bound to CLPP once dissociated. BIM did not influence association of PKCα with rMT but suppressed apoA-I-induced cholesterol translocation to the cytosol from the ER/Golgi apparatus and apoA-I-mediated cholesterol release. We thereby concluded that α-tubulin phosphorylation by PKCα on CLPP is involved in reversible CLPP association with the microtubules and intracellular cholesterol trafficking for apoA-I-dependent HDL biogenesis/cholesterol release in rat astrocytes.

Involvement of cdc42/Rho kinase in apoA-I-mediated cholesterol efflux through interaction between cytosolic lipid-protein particles and microtubules in rat astrocytes.

Activation of cdc42 reportedly enhances apoA-I-mediated cholesterol release through ATP-binding cassette transporter A1 (ABCA1). We examined the involvement of cdc42 and Rho kinase in intracellular cholesterol transport for release of cholesterol after the interaction between apoA-I and ABCA1 in astrocytes. Exogenously added apoA-I increased the GTP-bound form of cdc42 and enhanced Rho kinase activity in rat astrocytes. Suppression of ABCA1 expression by siRNA substantially repressed both cellular level of GTP-bound cdc42 and Rho kinase activity, indicating that these reactions require ABCA1. ApoA-I-mediated lipid release and Rho kinase activation were inhibited by not only Rho kinase inhibitor but also cdc42 siRNA. These findings suggest that cdc42 is activated by the interaction between apoA-I and ABCA1 and enhances cholesterol release through the activation of Rho kinase. ApoA-I increased the binding of Rock1, one of the Rho kinases, to reconstituted microtubule-like filaments (rMT). Y-27632 suppressed not only the association of rMT with the cytosolic lipid-protein particles (CLPP)-related proteins and lipids but also the intracellular transport of newly synthesized cholesterol to the plasma membrane in rat astrocytes treated with apoA-I without inhibiting cholesterol synthesis. Finally, cdc42 siRNA reduced apoA-I-induced interaction between rMT and major players in intracellular cholesterol trafficking, such as caveolin-1 and Rock1, suggesting a regulatory role of Rho family proteins in the apoA-I-mediated intracellular cholesterol transport. We conclude that ABCA1/cdc42/Rho kinase signaling is involved in apoA-I-induced intracellular cholesterol transport and apoA-I-mediated cholesterol release in rat astrocytes.

CD36-related protein in Schistosoma japonicum: candidate mediator of selective cholesteryl ester uptake from high-density lipoprotein for egg maturation.

Familial cholesteryl ester transfer protein (CETP) deficiency is more common in some East Asian populations than elsewhere, suggesting the possibility of a selective advantage of this genetic defect against regional infectious diseases. Historically, infection with the Asian blood fluke Schistosoma japonicum has been endemic in these regions, including Japan. We previously reported that eggs of S. japonicum require cholesteryl ester uptake from normal high-density lipoprotein (HDL) but not from CETP-deficient HDL for their maturation to miracidia, a critical step of the hepatic pathogenesis of schistosomiasis. Herein we show that cholesteryl ester uptake is selective from HDL, and identified CD36-related protein (CD36RP) as a candidate to mediate the reaction. CD36RP was cloned from the adult and the egg developmental stages of S. japonicum, with 1880 bp encoding 506 amino acid residues exhibiting the CD36 domains and two transmembrane regions. Using antibodies against recombinant peptides representing the potential extracellular domains of CD36RP, Western blotting detected a protein with a molecular mass of 82 kDa in the particulate fraction of the adult parasite cells, which was reduced to 62 kDa after N-glycanase treatment. The extracellular domain peptide bound human HDL, as established by immunoblots following nondenaturing gel electrophoresis. Antibodies against the extracellular domain suppressed HDL cholesteryl ester uptake and maturation of the eggs in vitro. CD36RP is a candidate receptor on eggs of S. japonicum that facilitates uptake of HDL cholesteryl ester necessary for egg embryonation and maturation.

Transitional Medicine of Intractable Primary Dyslipidemias in Japan.

Transitional medicine refers to the seamless continuity of medical care for patients with childhood-onset diseases as they grow into adulthood. The transition of care must be seamless in medical treatment as the patients grow and in other medical aids such as subsidies for medical expenses in the health care system. Inappropriate transitional care, either medical or social, directly causes poorer prognosis for many early-onset diseases, including primary dyslipidemia caused by genetic abnormalities. Many primary dyslipidemias are designated as intractable diseases in the Japanese health care system for specific medical aids, as having no curative treatment and requiring enormous treatment costs for lipid management and prevention of complications. However, there are problems in transitional medicine for primary dyslipidemia in Japan. As for the medical treatment system, the diagnosis rate remains low due to the shortage of specialists, their insufficient link with generalists and other field specialists, and poor linkage between pediatricians and physicians for adults. In the medical care system, there is a mismatch of diagnostic criteria of primary dyslipidemias between children and adults for medical care expense subsidization, as between The Program for the Specific Pediatric Chronic Diseases and the Program for Designated Adult Intractable Diseases. This could lead some patients subsidized in their childhood to no longer be under the coverage of the aids after transition. This review intends to describe these issues in transitional medicine of primary dyslipidemia in Japan as a part of the efforts to resolve the problems by the Committee on Primary Dyslipidemia under the Research Program on Rare and Intractable Disease of the Ministry of Health, Labour and Welfare of Japan.

Molecular Insights into O-Linked Sialoglycans Recognition by the Siglec-Like SLBR-N (SLBRUB10712) of Streptococcus gordonii.

Streptococcus gordonii is a Gram-positive bacterial species that typically colonizes the human oral cavity, but can also cause local or systemic diseases. Serine-rich repeat (SRR) glycoproteins exposed on the S. gordonii bacterial surface bind to sialylated glycans on human salivary, plasma, and platelet glycoproteins, which may contribute to oral colonization as well as endocardial infections. Despite a conserved overall domain organization of SRR adhesins, the Siglec-like binding regions (SLBRs) are highly variable, affecting the recognition of a wide range of sialoglycans. SLBR-N from the SRR glycoprotein of S. gordonii UB10712 possesses the remarkable ability to recognize complex core 2 O-glycans. We here employed a multidisciplinary approach, including flow cytometry, native mass spectrometry, isothermal titration calorimetry, NMR spectroscopy from both protein and ligand perspectives, and computational methods, to investigate the ligand specificity and binding preferences of SLBR-N when interacting with mono- and disialylated core 2 O-glycans. We determined the means by which SLBR-N preferentially binds branched α2,3-disialylated core 2 O-glycans: a selected conformation of the 3'SLn branch is accommodated into the main binding site, driving the sTa branch to further interact with the protein. At the same time, SLBR-N assumes an open conformation of the CD loop of the glycan-binding pocket, allowing one to accommodate the entire complex core 2 O-glycan. These findings establish the basis for the generation of novel tools for the detection of specific complex O-glycan structures and pave the way for the design and development of potential therapeutics against streptococcal infections.

Calpain-mediated ABCA1 degradation: post-translational regulation of ABCA1 for HDL biogenesis.

Helical apolipoproteins remove cellular phospholipid and cholesterol to generate nascent HDL and this reaction is the major source of plasma HDL. ABCA1 is mandatory and rate-limiting for this reaction. Besides regulation of the gene expression by transcriptional factors including LXR, AP2 and SREBP, the ABCA1 activity is regulated post-translationally by calpain-mediated proteolytic degradation of ABCA1 protein that occurs in the early endosome after its endocytosis. When the HDL biogenesis reaction is ongoing as helical apolipoproteins interact with ABCA1, ABCA1 becomes resistant to calpain and is recycled to cell surface after endocytosis. Biogenesis of HDL is most likely to take place on cell surface. Clearance rate of ABCA1 by this mechanism is also retarded by various factors that interact with ABCA1, such as α1-syntrophin, LXRß and calmodulin. Physiological relevance of the retardation by these factors is not entirely clear. Pharmacological inhibition of the calpain-mediated ABCA1 degradation results in the increase of the ABCA1 activity and HDL biogenesis in vitro and in vivo, and potentially suppresses atherogenesis. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).

Continuous and Marked Increase of Japanese HDL Associates Paradoxically with their Nutritional Shift.

AIMS: Plasma HDL has evidently increased for decades among Japanese, exclusively in HDL particles containing apoA-I but not A-II. Its metabolic background is yet to be elucidated. METHODS: Trends in plasma lipoproteins were analyzed by examining data on total cholesterol, triglyceride and HDL-cholesterol, which are available in the public database of the National Health and Nutrition Examination Survey of Japan (NHNESJ) and in the clinical data of SRL Co., from 1989 to 2019, estimating cholesterol (C) in non-HDL, VLDL, LDL, and sub-fractions of LDL using the equations by Sampson et al. Food intake and supply data in NHNSJ and in the UN Food and Agriculture Organization were also analyzed in relation to the lipoprotein analysis. RESULTS: HDL-C levels showed a steady increase in men and women throughout the period as per the data retrieved in NHNSJ and SRL data. It is noted to be higher in women than men (from 46.8 to 52.7, and from 58.4 to 68.3 in mg/dl, respectively). Triglyceride and VLDL-C were higher in men but sex difference was not apparent in non-HDL-C and LDL-C levels, while these parameters slightly decreased in both sexes. The increase in HDL was most prominent in women in the age of 50 - 59 (from 57.0 to 73.4). The age-dependent HDL trend was reversed among women during the study period, as increasing instead of decreasing. This increase in HDL was found to coincide with lowered fish/meat ratio in food intake among Japanese. CONCLUSION: Marked increase in plasma HDL among Japanese is age- and sex-dependent and exhibited an apparent paradoxical association with lowered fish/meat ratio in their diet. Further investigation is required to elucidate the background for these findings.

Vaccination against the HDL receptor of S. japonicum inhibits egg embryonation and prevents fatal hepatic complication in rabbit model.

BACKGROUND: Schistosomiasis is one of the most important neglected tropical infectious diseases to overcome and the primary cause of its pathogenesis is ectopic maturation of the parasite eggs. Uptake of cholesteryl ester from the host high-density lipoprotein (HDL) is a key in this process in Schistosoma japonicum and CD36-related protein (CD36RP) has been identified as the receptor for this reaction. Antibody against the extracellular domain of CD36RP (Ex160) efficiently blocked the HDL cholesteryl ester uptake and the egg embryonation in vitro. However, whether Ex160 immunization could efficiently raise proper antibody responses to sufficiently block HDL cholesteryl ester uptake and the egg embryonation to protect host in vivo is very interesting but unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this study, rabbits were immunized with the recombinant Ex160 peptide (rEx160) to evaluate its anti-pathogenic vaccine potential. Immunization with rEx160 induced consistent anti-Ex160 IgG antibody and significant reduction in development of the liver granulomatosis lesions associated with suppressed intrahepatic maturation of the schistosome eggs. The immunization with rEx160 rescued reduction of serum HDL by the infection without changing its size distribution, being consistent with interference of the HDL lipid uptake by the parasites or their eggs by antibody against Ex160 in in vitro culture. CONCLUSIONS/SIGNIFICANCE: The results demonstrated that vaccination strategy against nutritional supply pathway of the parasite is effective for reducing its pathogenesis.