Plasma levels of apolipoprotein A1 in malaria-exposed primigravidae are associated with severe anemia

Protein Modification Characteristics of the Malaria Parasite Plasmodium falciparum and the Infected Erythrocytes

Malaria elimination is still pending on the development of novel tools that rely on a deep understanding of parasite biology. Proteins of all living cells undergo myriad posttranslational modifications (PTMs) that are critical to multifarious life processes. An extensive proteome-wide dissection revealed a fine PTM map of most proteins in both Plasmodium falciparum, the causative agent of severe malaria, and the infected red blood cells. More than two-thirds of proteins of the parasite and its host cell underwent extensive and dynamic modification throughout the erythrocytic developmental stage. PTMs critically modulate the virulence factors involved in the host-parasite interaction and pathogenesis. Furthermore, P. falciparum stabilized the supporting proteins of erythrocyte origin by selective demodification. Collectively, our multiple omic analyses, apart from having furthered a deep understanding of the systems biology of P. falciparum and malaria pathogenesis, provide a valuable resource for mining new antimalarial targets.

KSHV oral shedding and plasma viremia result in significant changes in the extracellular tumorigenic miRNA expression profile in individuals infected with the malaria parasite

Kaposi's sarcoma herpesvirus (KSHV) is the etiological agent of Kaposi’s sarcoma (KS). Both KSHV and HIV infections are endemic in Uganda, where KS is among the most common cancers in HIV-infected individuals. Recent studies examined the use of small RNAs as biomarkers of disease, including microRNAs (miRNAs), with viral and tumor-derived miRNAs being detected in exosomes from individuals with KSHV-associated malignancies. In the current study, the host and viral extracellular mature miRNA expression profiles were analyzed in blood of KS-negative individuals in Uganda, comparing those with or without KSHV detectable from the oropharynx. We observed increased levels of cellular oncogenic miRNAs and decreased levels of tumor-suppressor miRNAs in plasma of infected individuals exhibiting oral KSHV shedding. These changes in host oncomiRs were exacerbated in people co-infected with HIV, and partially reversed after 2 years of anti-retroviral therapy. We also detected KSHV miRNAs in plasma of KSHV infected individuals and determined that their expression levels correlated with KSHV plasma viremia. Deep sequencing revealed an expected profile of small cellular RNAs in plasma, with miRNAs constituting the major RNA biotype. In contrast, the composition of small RNAs in exosomes was highly atypical with high levels of YRNA and low levels of miRNAs. Mass spectrometry analysis of the exosomes revealed eleven different peptides derived from the malaria parasite, Plasmodium falciparum, and small RNA sequencing confirmed widespread plasmodium co-infections in the Ugandan cohorts. Proteome analysis indicated an exosomal protein profile consistent with erythrocyte and keratinocyte origins for the plasma exosomes. A strong correlation was observed between the abundance of Plasmodium proteins and cellular markers of malaria. As Plasmodium falciparum is an endemic pathogen in Uganda, our study shows that co-infection with other pathogens, such as KSHV, can severely impact the small RNA repertoire, complicating the use of exosome miRNAs as biomarkers of disease.

Peripheral and placental biomarkers in women with placental malaria: a systematic review

Placental malaria (PM) causes significant morbidity in mothers and infants. Diagnosis of PM during pregnancy is however problematic due to placental sequestration of parasites. Host biomarkers may therefore be used as a diagnostic method. In this systematic review most studies focused on inflammatory markers. A trend was observed for increased IL-10 and TNF-α in PM positives. These markers are however unspecific, thus a combination of multiple biomarkers involved in different pathophysiological pathways of PM is indicated. Of interest are inflammatory markers (TNF-R2, CXCL-13), markers of lipid metabolism (APO-B), angiogenesis (sFlt-1) and hormones (estradiol). As the majority of published studies tested biomarker levels only at delivery, more longitudinal cohort studies will be necessary to detect biomarkers during pregnancy that can predict PM.

High-density lipoprotein modulates thrombosis by preventing von Willebrand factor self-association and subsequent platelet adhesion

The ability of von Willebrand factor (VWF) to initiate platelet adhesion depends on the number of monomers in individual VWF multimers and on the self-association of individual VWF multimers into larger structures. VWF self-association is accelerated by shear stress. We observed that VWF self-association occurs during adsorption of VWF onto surfaces, assembly of secreted VWF into hyperadhesive VWF strings on the endothelial surface, and incorporation of fluid-phase VWF into VWF fibers. VWF adsorption under static conditions increased with increased VWF purity and was prevented by a component of plasma. We identified that component as high-density lipoprotein (HDL) and its major apolipoprotein ApoA-I. HDL and ApoA-I also prevented VWF on the endothelium from self-associating into longer strands and inhibited the attachment of fluid-phase VWF onto vessel wall strands. Platelet adhesion to VWF fibers was reduced in proportion to the reduction in self-associated VWF. In a mouse model of thrombotic microangiopathy, HDL also largely prevented the thrombocytopenia induced by injection of high doses of human VWF. Finally, a potential role for ApoA-I in microvascular occlusion associated with thrombotic thrombocytopenic purpura and sepsis was revealed by the inverse relationship between the concentration of ApoA-I and that of hyperadhesive VWF. These results suggest that interference with VWF self-association would be a new approach to treating thrombotic disorders.

Serum Apolipoprotein-A1 and Cholesterol Levels in Nigerian Children with Plasmodium falciparum Infection

OBJECTIVE

This study was carried out to determine whether or not Plasmodium falciparum malaria infection significantly affected apolipoprotein-A1 and cholesterol levels and if apolipoprotein-A1 correlated with the malaria severity in children younger than 5 years old.

SUBJECTS AND METHODS

Two hundred and fifty-five children, 170 of whom had microscopically confirmed P. falciparum infection, i.e. 85 cases of uncomplicated malaria (UM) and 85 of complicated malaria (CM), and 85 healthy controls were enrolled in this study. Serum levels of apolipoprotein-A1, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglycerides were determined. These levels were compared among the malaria and control groups, using ANOVA and post hoc analyses at p = 0.05.

RESULTS

There were significant differences in the mean serum levels of apolipoprotein-A1 (UM: 104.5 ± 38.1 mg/dl, CM: 90.9 ± 33.3 mg/dl and controls: 129.7 ± 48.3 mg/dl; p < 0.001), total cholesterol (UM: 138.8 ± 62.9 mg/dl, CM: 121.2 ± 55.2 mg/dl and controls: 155.1 ± 69.8 mg/dl; p = 0.002) and LDL (UM: 98.2 ± 55.5 mg/dl, CM: 84.3 ± 47.4 mg/dl and controls: 122.7 ± 69.4 mg/dl; p < 0.001). Post hoc analyses revealed that children with UM and CM had significantly lower levels of apolipoprotein-A1, cholesterol, HDL and LDL than controls but that there was no difference between the 2 malaria groups. Reductions in levels of lipids and apolipoprotein-A1 were worse in CM than in UM.

CONCLUSION

Altered levels of serum lipids with CM were associated with a reduction in apolipoprotein-A1. These findings have potential diagnostic utility for the management of malaria.

Correlation of apolipoprotein A-I kinetics with survival and response to first-line platinum-based chemotherapy in advanced non-small cell lung cancer

The aim of this study was to determine whether apolipoprotein A-I (ApoA-I) kinetics predict the overall survival in patients with advanced-stage non-small cell lung cancer (NSCLC) during platinum-based first-line therapy. A total of 125 NSCLC patients from January 2008 to September 2014 were retrospectively reviewed. Serum ApoA-I level was measured at baseline and thereafter at the start of each palliative chemotherapy cycle for all patients. Patients were divided into four groups according to ApoA-I kinetics. Patients whose ApoA-I ≥ 1.01 g/L and never decreased during treatment, patients whose ApoA-I ≥ 1.01 g/L and decreased (ApoA-I < 1.01 g/L) at least one time during treatment, patients whose ApoA-I < 1.01 g/L and normalized (ApoA-I ≥ 1.01) at least one time during treatment, and patients whose ApoA-I < 1.01 g/L and never normalized during treatment were assigned to non-decreased, decreased, normalized, and non-normalized ApoA-I groups, respectively. Overall survival rates were significantly different between the four groups, with 2-year survival rates of 88.6 and 17.5 % for the non-decreased and the decreased ApoA-I groups, respectively, and none survived 2 years later in the normalized and the non-normalized ApoA-I groups. When compared with the non-decreased group, the hazard ratios of death were 0.05, 0.44, and 1.73 in the normalized, decreased, and non-normalized groups, respectively (P < 0.001). Normalization of ApoA-I was associated with a low risk of progression, whereas patients with a decreased level of ApoA-I showed a progression of disease in most cases. ApoA-I can be a novel, widely available biomarker for patients with NSCLC.

Ability of a biomarker-based score to predict death from circulatory disease and cancer in NHANES III

Background

A score based on serum concentrations of C-reactive protein (CRP), albumin, gamma-glutamyl transferase (GGT), and HDL cholesterol was positively associated with death from cancer, circulatory disease, and all-cause mortality. We replicated this in the third National Health and Nutrition Examination Survey (NHANES III), a US nationally representative survey conducted between 1988–1994.

Methods

Baseline measurements of CRP, albumin, GGT, and HDL were available for participants with mortality follow-up (n=13,056). A biomarker score, ranging 0–4, was created by adding number of markers with abnormal values (cut-off: CRP>10mg/L, albumin<35mg/L, GGT>36U/L, HDL<1.04mmol/L). Its association with mortality was analyzed with multivariate Cox proportional hazards models.

Results

The score was positively associated with death from all causes, cancer and circulatory disease [e.g. HR all-cause mortality: 1.21 (95% CI: 1.09, 1.35), 1.92 (1.67, 2.20), 3.38 (2.62, 4.36), and 7.93 (5.77, 10.89), for score 1, 2, 3, 4 vs.0]. These patterns were found across the Charlson Comorbidity Index (CCI). Where CCI =3, risk of cancer death was 1.09 (0.93, 1.28), 1.81 (1.43, 2.29), 4.67 (3.05, 7.14), and 6.97 (5.32, 9.14) for score 1, 2, 3, 4 vs. 0. No effect-modification by sex or race/ethnicity was observed.

Conclusions

These findings correlate with results from a Swedish study. This biomarker-based score could help clinicians make decisions in prevention and disease management.

The association of a distinct plasma proteomic profile with the cervical high-grade squamous intraepithelial lesion of Uyghur women: a 2D liquid-phase chromatography/mass spectrometry study

OBJECTIVE

To identify plasma protein biomarkers of cervical high-grade squamous intraepithelial lesion (HSIL) of Uyghur women by proteomics approach.

METHODS

Plasma protein samples of Uyghur women with HSIL and chronic cervicitis were analyzed with 2D HPLC followed by detection of target proteins with Linear Trap Quadrupole Mass Spectrometer (LTQ MS/MS).

RESULTS

We detected three upregulated and one downregulated protein peaks representing protein constituents distinguishing HSIL from controls by 2D HPLC, identified 31 target proteins by LTQ MS/MS. Further confirmed analysis with online software IPA® 8.7 and ELISA assay showed APOA1 and mTOR as potential biomarkers.

CONCLUSIONS

A distinct plasma proteomic profile may be associated with HSIL of Uyghur women.

Serum proteome analysis of vivax malaria: An insight into the disease pathogenesis and host immune response

Vivax malaria is the most widely distributed human malaria resulting in 80-300 million clinical cases every year. It causes severe infection and mortality but is generally regarded as a benign disease and has not been investigated in detail. The present study aimed to perform human serum proteome analysis in a malaria endemic area in India to identify potential serum biomarkers for vivax malaria and understand host response. The proteomic analysis was performed on 16 age and gender matched subjects (vivax patients and control) in duplicate. Protein extraction protocols were optimized for large coverage of the serum proteome and to obtain high-resolution data. Identification of 67 differentially expressed and statistically significant (Student's t-test; p<0.05) protein spots was established by MALDI-TOF/TOF mass spectrometry. Many of the identified proteins such as apolipoprotein A and E, serum amyloid A and P, haptoglobin, ceruloplasmin, and hemopexin are interesting from a diagnostic point of view and could further be studied as potential serum biomarkers. The differentially expressed serum proteins in vivax malaria identified in this study were subjected to functional pathway analysis using multiple software, including Ingenuity Pathway Analysis (IPA), Protein ANalysis THrough Evolutionary Relationships (PANTHER) and Database for Annotation, Visualization and Integrated Discovery (DAVID) functional annotation tool for better understanding of the biological context of the identified proteins, their involvement in various physiological pathways and association with disease pathogenesis. Functional pathway analysis of the differentially expressed proteins suggested the modulation of multiple vital physiological pathways, including acute phase response signaling, complement and coagulation cascades, hemostasis and vitamin D metabolism pathway due to this parasitic infection. This article is part of a Special Issue entitled: Proteomics: The clinical link.

Low levels of apolipoprotein A-I and HDL are associated with risk of prostate cancer in the Swedish AMORIS study

BACKGROUND

A detailed analysis of lipid profiles, using apolipoproteins, has not yet been conducted for prostate cancer (PCa). Since several etiological pathways have been proposed for PCa and lipids, we aimed to study this in a large Swedish cohort with 1,469 primary prostate cancers.

METHODS

A cohort (n = 69,735) of all men aged 35 years or older, whose levels of triglycerides (TG) (mmol/L), total cholesterol (mmol/L), glucose (mmol/L), LDL (mmol/L), HDL (mmol/L), apoB (g/L), and apoA-I (g/L) were measured at baseline, was selected from the Apolipoprotein MOrtality RISk (AMORIS) database. About 2,008 men developed PCa. Multivariate Cox proportional hazard models were used to analyze associations between lipid components and PCa.

RESULTS

ApoA-I and HDL were inversely associated with PCa risk (e.g., HR for HDL: 0.93 (95% CI: 0.81-1.07), 0.88 (0.76-1.01), 0.81 (0.70-0.94), for second, third, and fourth quartiles compared with the first quartile; with p for trend: 0.004; HR for apoA-I: 1.00 (0.88-1.13), 0.93 (0.82-1.05), 0.88 (0.77-0.99),), for second, third, and fourth quartiles compared with the first quartile; with p for trend: 0.022). ApoB, LDL, and non-HDL were not associated with PCa risk.

CONCLUSIONS

Our results show that low HDL and ApoA-I as well as increased lipid ratios are related to increased PCa risk. Experimental studies are required to tease out the underlying biological mechanisms linking these lipid components to PCa.