Proteomic Alterations of HDL in Youth with Type 1 Diabetes and their Associations with Glycemic Control: A Case-Control Study

Background: Patients with type 1 diabetes (T1DM) typically have normal or even elevated plasma high density lipoprotein (HDL) cholesterol concentrations; however, HDL protein composition can be altered without a change in cholesterol content. Alteration of the HDL proteome can result in dysfunctional HDL particles with reduced ability to protect against cardiovascular disease (CVD). The objective of this study was to compare the HDL proteomes of youth with T1DM and healthy controls (HC) and to evaluate the influence of glycemic control on HDL protein composition. Methods: This was a cross-sectional case–control study. Blood samples were obtained from patients with T1DM and HC. HDL was isolated from plasma by size-exclusion chromatography and further purified using a lipid binding resin. The HDL proteome was analyzed by mass spectrometry using label-free SWATH peptide quantification. Results: Samples from 26 patients with T1DM and 13 HC were analyzed and 78 HDL-bound proteins were measured. Youth with T1DM had significantly increased amounts of complement factor H related protein 2 (FHR2; adjusted P \u3c 0.05), compared to HC. When patients were analyzed based on glucose control, several trends emerged. Some proteins were altered in T1DM and not influenced by glycemic control (e.g. FHR2) while others were partially or completely corrected with optimal glucose control (e.g. alpha-1-beta glycoprotein, A1BG). In a subgroup of poorly controlled T1DM patients, inter alpha trypsin inhibitor 4 (ITIH4) was dramatically elevated (P \u3c 0.0001) and this was partially reversed in patients with optimal glucose control. Some proteins including complement component C3 (CO3) and albumin (ALB) were significantly different only in T1DM patients with optimal glucose control, suggesting a possible effect of exogenous insulin. Conclusions: Youth with T1DM have proteomic alterations of their HDL compared to HC, despite similar concentration of HDL cholesterol. The influence of these compositional changes on HDL function are not yet known. Future efforts should focus on investigating the role of these HDL associated proteins in regard to HDL function and their role in CVD risk in patients with T1DM. Trial registration NCT0227509

Identification of a Filamin Docking Site on PTP-PEST

PTP-PEST is a cytoplasmic protein-tyrosine phosphatase (PTP) implicated in the regulation of biological processes such as cell motility, cytokinesis, focal adhesion disassembly, and lymphocyte activation. Using a proteomics approach, filamin-A was identified as a novel interacting protein that bound to GST-PTP-PEST. This interaction was confirmed in vitro and in cells by coimmunoprecipitation. The site of filamin interaction on PTP-PEST was mapped to the fourth proline-rich region (Pro4). PTP-PEST has previously been implicated in the regulation of cytokinesis. In further support of this finding, expression of PTP-PEST in HeLa cells resulted in the formation of multinucleated cells. A PTP-PEST mutant lacking Pro4 and unable to bind filamin-A failed to induce the multinucleated phenotype. Further, depletion of filamin-A in HeLa cells was found to reduce the PTP-PEST-dependent multinucleation phenotype. Hence, we conclude that the interaction of PTP-PEST with filamin-A may function in the control of cytokinesis in mammalian cells

Effect of Metformin on the High-Density Lipoprotein Proteome in Youth with Type 1 Diabetes

Background: Youth with type 1 diabetes (T1D) have normal or elevated High-Density Lipoprotein Cholesterol (HDL-C), however, the function of HDL, partly mediated by the HDL proteome, may be impaired. Metformin can be used as an adjunct therapy in youth with T1D, but its effects on the HDL proteome are unknown. Objective: To determine the effect of metformin on the HDL proteome. Subjects: Youth (12-20 years old) with T1D who had a BMI \u3e 90th percentile, HbA1c \u3e 8.0% and Tanner stage 5. Methods: Double-blinded, placebo-controlled randomized sub-study. We examined the effects of metformin (n = 25) or placebo (n = 10) after 6 months on HDL proteome. Changes in HDL proteins were measured by data-independent acquisition (DIA) mass spectrometry and compared between treatment groups. As a secondary outcome, associations between proteins of interest and the most studied function of HDL, the cholesterol efflux capacity (CEC), was examined. Results: The relative abundance of 84 HDL-associated proteins were measured. Two proteins were significantly affected by metformin treatment, peptidoglycan recognition protein 2 (PGRP2; +23.4%, p = .0058) and alpha-2-macroglobulin (A2MG; +29.8%, p = .049). Metformin did not significantly affect CEC. Changes in affected HDL proteins did not correlate with CEC. Conclusions: Despite having little effect on HDL-C, metformin increased PGRP2 and A2MG protein on HDL in youth with T1D, but had no significant effect on CEC. Further studies are needed to understand the impact of PGRP2 and A2MG on other HDL functions

Interaction of the Human Papillomavirus E6 Oncoprotein with Sorting Nexin 27 Modulates Endocytic Cargo Transport Pathways

A subset of high-risk Human Papillomaviruses (HPVs) are the causative agents of a large number of human cancers, of which cervical is the most common. Two viral oncoproteins, E6 and E7, contribute directly towards the development and maintenance of malignancy. A characteristic feature of the E6 oncoproteins from cancer-causing HPV types is the presence of a PDZ binding motif (PBM) at its C-terminus, which confers interaction with cellular proteins harbouring PDZ domains. Here we show that this motif allows E6 interaction with Sorting Nexin 27 (SNX27), an essential component of endosomal recycling pathways. This interaction is highly conserved across E6 proteins from multiple high-risk HPV types and is mediated by a classical PBM-PDZ interaction but unlike many E6 targets, SNX27 is not targeted for degradation by E6. Rather, in HPV-18 positive cell lines the association of SNX27 with components of the retromer complex and the endocytic transport machinery is altered in an E6 PBM-dependent manner. Analysis of a SNX27 cargo, the glucose transporter GLUT1, reveals an E6-dependent maintenance of GLUT1 expression and alteration in its association with components of the endocytic transport machinery. Furthermore, knockdown of E6 in HPV-18 positive cervical cancer cells phenocopies the loss of SNX27, both in terms of GLUT1 expression levels and its vesicular localization, with a concomitant marked reduction in glucose uptake, whilst loss of SNX27 results in slower cell proliferation in low nutrient conditions. These results demonstrate that E6 interaction with SNX27 can alter the recycling of cargo molecules, one consequence of which is modulation of nutrient availability in HPV transformed tumour cells

Effect of Niacin Monotherapy on High Density Lipoprotein Composition and Function

BACKGROUND: Niacin has modest but overall favorable effects on plasma lipids by increasing high density lipoprotein cholesterol (HDL-C) and lowering triglycerides. Clinical trials, however, evaluating niacin therapy for prevention of cardiovascular outcomes have returned mixed results. Recent evidence suggests that the HDL proteome may be a better indicator of HDL\u27s cardioprotective function than HDL-C. The objective of this study was to evaluate the effect of niacin monotherapy on HDL protein composition and function. METHODS: A 20-week investigational study was performed with 11 participants receiving extended-release niacin (target dose = 2 g/day) for 16-weeks followed by a 4-week washout period. HDL was isolated from participants at weeks: 0, 16, and 20. The HDL proteome was analyzed at each time point by mass spectrometry and relative protein quantification was performed by label-free precursor ion intensity measurement. RESULTS: In this cohort, niacin therapy had typical effects on routine clinical lipids (HDL-C + 16%, q \u3c 0.01; LDL-C - 20%, q \u3c 0.01; and triglyceride - 15%, q = 0.1). HDL proteomics revealed significant effects of niacin on 5 proteins: serum amyloid A (SAA), angiotensinogen (AGT), apolipoprotein A-II (APOA2), clusterin (CLUS), and apolipoprotein L1 (APOL1). SAA was the most prominently affected protein, increasing 3-fold in response to niacin (q = 0.008). Cholesterol efflux capacity was not significantly affected by niacin compared to baseline, however, stopping niacin resulted in a 9% increase in efflux (q \u3c 0.05). Niacin did not impact HDL\u27s ability to influence endothelial function. CONCLUSION: Extended-release niacin therapy, in the absence of other lipid-modifying medications, can increase HDL-associated SAA, an acute phase protein associated with HDL dysfunction

Understanding Society Innovation Panel Wave 11: Results from Methodological Experiments

This is the final version. Available from the University of Essex via the link in this recordThis paper presents some preliminary findings from Wave 11 of the Innovation Panel (IP11) of Understanding Society: The UK Household Longitudinal Study. Understanding Society is a major panel survey in the UK. In May 2018, the eleventh wave of the Innovation Panel went into the field. IP11 used a mixed-mode design, using on-line interviews and face-to-face interviews. This paper describes the design of IP11, the experiments carried and the preliminary findings from early analysis of the data

Severity of Psoriasis Associates With Aortic Vascular Inflammation Detected by FDG PET/CT and Neutrophil Activation in a Prospective Observational Study.

This is the author accepted manuscript. The final version is available from the American Heart Association via http://dx.doi.org/10.1161/ATVBAHA.115.306460OBJECTIVE: To understand whether directly measured psoriasis severity is associated with vascular inflammation assessed by (18)F-fluorodeoxyglucose positron emission tomography computed tomography. APPROACH: In-depth cardiovascular and metabolic phenotyping was performed in adult psoriasis patients (n=60) and controls (n=20). Psoriasis severity was measured using psoriasis area severity index. Vascular inflammation was measured using average aortic target-to-background ratio using (18)F-fluorodeoxyglucose positron emission tomography computed tomography. RESULTS: Both the psoriasis patients (28 men and 32 women, mean age 47 years) and controls (13 men and 7 women, mean age 41 years) were young with low cardiovascular risk. Psoriasis area severity index scores (median 5.4; interquartile range 2.8-8.3) were consistent with mild-to-moderate skin disease severity. Increasing psoriasis area severity index score was associated with an increase in aortic target-to-background ratio (β=0.41, P=0.001), an association that changed little after adjustment for age, sex, and Framingham risk score. We observed evidence of increased neutrophil frequency (mean psoriasis, 3.7±1.2 versus 2.9±1.2; P=0.02) and activation by lower neutrophil surface CD16 and CD62L in blood. Serum levels of S100A8/A9 (745.1±53.3 versus 195.4±157.8 ng/mL; P<0.01) and neutrophil elastase-1 (43.0±2.4 versus 30.8±6.7 ng/mL; P<0.001) were elevated in psoriasis. Finally, S100A8/A9 protein was related to both psoriasis skin disease severity (β=0.53; P=0.02) and vascular inflammation (β=0.48; P=0.02). CONCLUSIONS: Psoriasis severity is associated with vascular inflammation beyond cardiovascular risk factors. Psoriasis increased neutrophil activation and neutrophil markers, and S100A8/A9 was related to both skin disease severity and vascular inflammation.JMT is supported by a Wellcome Trust research training fellowship (104492/Z/14/Z) and the NIHR Cambridge Biomedical Research Centre. JHFR is part-supported by the HEFCE, the NIHR Cambridge Biomedical Research Centre, the British Heart Foundation, and the Wellcome Trus

Cell-free, high-density lipoprotein-specific phospholipid efflux assay predicts incident cardiovascular disease

BACKGROUND. Cellular cholesterol efflux capacity (CEC) is a better predictor of cardiovascular disease (CVD) events than HDLcholesterol (HDL-C) but is not suitable as a routine clinical assay.METHODS. We developed an HDL-specific phospholipid efflux (HDL-SPE) assay to assess HDL functionality based on whole plasma HDL apolipoprotein-mediated solubilization of fluorescent phosphatidylethanolamine from artificial lipid donor particles. We first assessed the association of HDL-SPE with prevalent coronary artery disease (CAD): study I included NIH severe-CAD (n = 50) and non-CAD (n = 50) participants, who were frequency matched for sex, BMI, type 2 diabetes mellitus, and smoking; study II included Japanese CAD (n = 70) and non-CAD (n = 154) participants. We also examined the association of HDL-SPE with incident CVD events in the Prevention of Renal and Vascular End-stage Disease (PREVEND) study comparing 340 patients with 340 controls individually matched for age, sex, smoking, and HDL-C levels.RESULTS. Receiver operating characteristic curves revealed stronger associations of HDL-SPE with prevalent CAD. The AUCs in study I were as follows: HDL-SPE, 0.68; apolipoprotein A-I (apoA-I), 0.62; HDL-C, 0.63; and CEC, 0.52. The AUCs in study II were as follows: HDL-SPE, 0.83; apoA-I, 0.64; and HDL-C, 0.53. Also longitudinally, HDL-SPE was significantly associated with incident CVD events independent of traditional risk factors with ORs below 0.2 per SD increment in the PREVEND study (P &lt; 0.001).CONCLUSION. HDL-SPE could serve as a routine clinical assay for improving CVD risk assessment and drug discovery.</p

Cell-free, high-density lipoprotein-specific phospholipid efflux assay predicts incident cardiovascular disease

BACKGROUND. Cellular cholesterol efflux capacity (CEC) is a better predictor of cardiovascular disease (CVD) events than HDLcholesterol (HDL-C) but is not suitable as a routine clinical assay.METHODS. We developed an HDL-specific phospholipid efflux (HDL-SPE) assay to assess HDL functionality based on whole plasma HDL apolipoprotein-mediated solubilization of fluorescent phosphatidylethanolamine from artificial lipid donor particles. We first assessed the association of HDL-SPE with prevalent coronary artery disease (CAD): study I included NIH severe-CAD (n = 50) and non-CAD (n = 50) participants, who were frequency matched for sex, BMI, type 2 diabetes mellitus, and smoking; study II included Japanese CAD (n = 70) and non-CAD (n = 154) participants. We also examined the association of HDL-SPE with incident CVD events in the Prevention of Renal and Vascular End-stage Disease (PREVEND) study comparing 340 patients with 340 controls individually matched for age, sex, smoking, and HDL-C levels.RESULTS. Receiver operating characteristic curves revealed stronger associations of HDL-SPE with prevalent CAD. The AUCs in study I were as follows: HDL-SPE, 0.68; apolipoprotein A-I (apoA-I), 0.62; HDL-C, 0.63; and CEC, 0.52. The AUCs in study II were as follows: HDL-SPE, 0.83; apoA-I, 0.64; and HDL-C, 0.53. Also longitudinally, HDL-SPE was significantly associated with incident CVD events independent of traditional risk factors with ORs below 0.2 per SD increment in the PREVEND study (P &lt; 0.001).CONCLUSION. HDL-SPE could serve as a routine clinical assay for improving CVD risk assessment and drug discovery.</p

Cell-free, high-density lipoprotein-specific phospholipid efflux assay predicts incident cardiovascular disease

BACKGROUND. Cellular cholesterol efflux capacity (CEC) is a better predictor of cardiovascular disease (CVD) events than HDLcholesterol (HDL-C) but is not suitable as a routine clinical assay.METHODS. We developed an HDL-specific phospholipid efflux (HDL-SPE) assay to assess HDL functionality based on whole plasma HDL apolipoprotein-mediated solubilization of fluorescent phosphatidylethanolamine from artificial lipid donor particles. We first assessed the association of HDL-SPE with prevalent coronary artery disease (CAD): study I included NIH severe-CAD (n = 50) and non-CAD (n = 50) participants, who were frequency matched for sex, BMI, type 2 diabetes mellitus, and smoking; study II included Japanese CAD (n = 70) and non-CAD (n = 154) participants. We also examined the association of HDL-SPE with incident CVD events in the Prevention of Renal and Vascular End-stage Disease (PREVEND) study comparing 340 patients with 340 controls individually matched for age, sex, smoking, and HDL-C levels.RESULTS. Receiver operating characteristic curves revealed stronger associations of HDL-SPE with prevalent CAD. The AUCs in study I were as follows: HDL-SPE, 0.68; apolipoprotein A-I (apoA-I), 0.62; HDL-C, 0.63; and CEC, 0.52. The AUCs in study II were as follows: HDL-SPE, 0.83; apoA-I, 0.64; and HDL-C, 0.53. Also longitudinally, HDL-SPE was significantly associated with incident CVD events independent of traditional risk factors with ORs below 0.2 per SD increment in the PREVEND study (P &lt; 0.001).CONCLUSION. HDL-SPE could serve as a routine clinical assay for improving CVD risk assessment and drug discovery.</p