Identification of Plasma Proteins as Biomarkers for Mild Cognitive Impairment and Alzheimer's Disease Using Liquid Chromatography-Tandem Mass Spectrometry.

Blood proteins can be used for biomarkers to monitor the progression of cognitive decline, even in the early stages of disease. In this study, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based blood test to identify plasma proteins that can be used to detect mild cognitive impairment (MCI) and Alzheimer's disease (AD). Using this system, we quantified plasma proteins using isotope-labeled synthetic peptides. A total of 192 patients, including 63 with AD, 71 with MCI, and 58 non-demented controls (NDCs), were analyzed. Multinomial regression and receiver operating characteristic (ROC) analyses were performed to identify specific combinations of plasma protein panels that could differentiate among NDCs, those with MCI, and those with AD. We identified eight plasma protein biomarker candidates that can be used to distinguish between MCI and AD. These biomarkers were associated with coagulation pathways, innate immunity, lipid metabolism, and nutrition. The clinical potential to differentiate cognitive impairment from NDC was assessed using area under the curve values from ROC analysis, which yielded values of 0.83 for males and 0.71 for females. This LC-MS-based plasma protein panel allows the pathophysiology of AD to be followed through detection of cognitive decline and disease progression markers.

Structural brain network correlations with amyloid burden in elderly individuals at risk of Alzheimer's disease.

Alzheimer's disease (AD) has a long preclinical phase during which beta-amyloid accumulates in the brain without cognitive impairment. However, the pattern of brain network alterations in this early stage of the disease remains to be clarified. In this study we examined the relationships between regional brain network indices and beta-amyloid deposits. Twenty-four elderly subjects with the APOE4 allele underwent both a 1.5-Tesla magnetic resonance imaging (MRI) scan and a positron emission tomography (PET) scan using [18F]Florbetapir. We computed network metrics such as the degree, betweenness centrality, and clustering coefficient, and examined the relationships between the beta-amyloid accumulation and these regional brain network connectivity metrics. We found a significant positive correlation between the global standardized uptake value ratio (SUVR) of [18F]Florbetapir and the betweenness centrality in the left parietal region. However, there were no significant correlations between the SUVR score and other network indices or the regional gray matter volume. Our data suggest a relationship between the beta-amyloid accumulation and the regional brain network connectivity in subjects at risk of AD. The brain connectome may provide an adjunct biomarker for the early detection of AD.

Excess hydrogen sulfide and polysulfides production underlies a schizophrenia pathophysiology.

Mice with the C3H background show greater behavioral propensity for schizophrenia, including lower prepulse inhibition (PPI), than C57BL/6 (B6) mice. To characterize as-yet-unknown pathophysiologies of schizophrenia, we undertook proteomics analysis of the brain in these strains, and detected elevated levels of Mpst, a hydrogen sulfide (H2 S)/polysulfide-producing enzyme, and greater sulfide deposition in C3H than B6 mice. Mpst-deficient mice exhibited improved PPI with reduced storage sulfide levels, while Mpst-transgenic (Tg) mice showed deteriorated PPI, suggesting that "sulfide stress" may be linked to PPI impairment. Analysis of human samples demonstrated that the H2 S/polysulfides production system is upregulated in schizophrenia. Mechanistically, the Mpst-Tg brain revealed dampened energy metabolism, while maternal immune activation model mice showed upregulation of genes for H2 S/polysulfides production along with typical antioxidative genes, partly via epigenetic modifications. These results suggest that inflammatory/oxidative insults in early brain development result in upregulated H2 S/polysulfides production as an antioxidative response, which in turn cause deficits in bioenergetic processes. Collectively, this study presents a novel aspect of the neurodevelopmental theory for schizophrenia, unraveling a role of excess H2 S/polysulfides production.

Serum levels of proteins involved in amyloid-ß clearance are related to cognitive decline and neuroimaging changes in mild cognitive impairment.

INTRODUCTION: Amyloid-ß (Aß) clearance is important for damage prevention in Alzheimer's disease. We investigated the utility of Aß clearance proteins as biomarkers for mild cognitive impairment (MCI). METHODS: Serum apolipoprotein (apo) A-I, compliment protein C3 (C3), transthyretin, and cholesterol levels were measured in 273 subjects, and we analyzed the relationship between these levels and brain atrophy and cerebral blood flow in 63 clinically diagnosed mild cognitive impairment, Alzheimer's disease, and nondemented disease control subjects. RESULTS: ApoA-I and transthyretin levels and the active form of C3:native form of C3 ratio achieved an area under the curve of 0.89 (sensitivity: 83%, specificity: 90%) for detecting late mild cognitive impairment. Atrophy was associated with decreased apoA-I and high-density lipoprotein levels. Subjects with reduced cerebral blood flow had lower levels of active form of C3, apoA-I, high-density lipoprotein, and total cholesterol. Low native form of C3 and high active form of C3 levels were found in the hippocampi of patients with Alzheimer's disease. DISCUSSION: Aß clearance proteins in the serum are potential biomarkers for mild cognitive impairment evaluation.

Amyloid-ß sequester proteins as blood-based biomarkers of cognitive decline.

INTRODUCTION: There are no blood-based biomarkers for cognitive decline in aging, or mild cognitive impairment (MCI) and Alzheimer's disease (AD). Cumulative evidence suggests that apolipoproteins, complement system, and transthyretin are involved in AD pathogenesis by sequestration of amyloid ß. However, there is no clinical study to assess the utility of "sequester proteins" in risk assessment and/or diagnosis of MCI and AD. METHODS: Serum levels of sequester proteins and their clinical potential in cognitive decline assessment were analyzed by longitudinal and cross-sectional studies using independent cohorts and were confirmed by a prospective study. RESULTS: A combination of apolipoprotein A1, complement C3, and transthyretin achieved an area under the curve of 0.89 (sensitivity 91% and specificity 80%) in MCI versus healthy controls and also discriminated individuals with mild cognitive decline from healthy controls. DISCUSSION: A set of sequester proteins could be blood-based biomarkers for assessment of early stages of cognitive decline.

Serum protein isoform profiles indicate the progression of hepatitis C virus-induced liver diseases.

Biomarkers that enable an accurate diagnosis of hepatitis C virus (HCV)-induced liver diseases are necessary to prevent subsequent patient morbidity and suffering from the onset of hepatocellular carcinoma (HCC). In particular, the identification of novel biomarkers for liver cirrhosis (LC) will be an important new diagnostic tool since more than 70% of HCV-induced LCs are destined to develop into HCC. In our current study, we performed a search for new serological protein biomarkers of HCV-induced chronic hepatitis (CH), LC and HCC, using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The disease-affected spots were subsequently identified as isoforms of protein components of haptoglobin, transthyretin, the haptoglobin α-chain and apolipoprotein A-IV (apo A-IV), and in specific instances were significantly reduced in LC (p<0.001) and HCC (p<0.01), compared with CH patients. We further examined these isoforms by receiver operating characteristics (ROC) curve analysis and found that they showed high area under ROC curve (AUC) values of more than 0.8 between CH and LC, suggesting that they are appropriate markers that could be utilized to discriminate LC from CH. In conclusion, protein variants in serum that arise as a result of post-translational modifications prove to be useful biomarkers for the accurate diagnosis of specific liver diseases.

Apolipoprotein A-IV is a candidate target molecule for the treatment of seasonal allergic rhinitis.

BACKGROUND: Allergic rhinitis is a global health problem that causes major illnesses and disability worldwide. Allergen-specific immunotherapy (SIT) is the only available treatment that can alter the natural course of allergic disease. However, the precise mechanism underlying allergen-SIT is not well understood. OBJECTIVE: The aim of the current study was to identify protein expression signatures reflective of allergen-SIT-more specifically, sublingual immunotherapy (SLIT). METHODS: Serum was taken twice from patients with seasonal allergic rhinitis caused by Japanese cedar: once before the pollen season and once during the season. A total of 25 patients was randomly categorized into a placebo-treated group and an active-treatment group. Their serum protein profiles were analyzed by 2-dimensional electrophoresis. RESULTS: Sixteen proteins were found to be differentially expressed during the pollen season. Among the differentially expressed proteins, the serum levels of complement C4A, apolipoprotein A-IV (apoA-IV), and transthyretin were significantly increased in SLIT-treated patients but not in placebo-treated patients. Among these proteins, the serum levels of apoA-IV correlated with the clinical symptom-medication scores (r = -0.635; P < .05) and with quality of life scores (r = -0.516; P < .05) in the case of SLIT-treated patients. The amount of histamine released from the basophils in vitro was greatly reduced after the addition of recombinant apoA-IV in the medium (P < .01). CONCLUSION: Our data will increase the understanding of the mechanism of SLIT and may provide novel insights into the treatment of allergic rhinitis.

FOXO1 and TCF7L2 genes involved in metastasis and poor prognosis in clear cell renal cell carcinoma.

The goal of this study was to identify genes related to the metastasis of clear cell renal cell carcinoma (CRCC). We analyzed copy number alterations in renal tissue specimens of patients with CRCC patients with or without metastasis by using high-resolution single-nucleotide polymorphism (SNP) arrays and then integrated these data with gene expression profiling data obtained using oligonucleotide microarrays. The expression levels of target genes were determined by quantitative real-time RT-PCR (qRT-PCR) with an independent tumor set. An analysis of specimens from 23 CRCC cases with SNP arrays revealed that hemizygous deletions at 10q and 13q were found only in cases of metastatic disease. We found the homozygous deletion of TCF7L2 at 10q25.2 in an aggressive case that had hemizygous deletions at 10q. In addition, a qRT-PCR analysis of TCF7L2 mRNA levels in tumor samples revealed significantly lower levels in patients with metastasis when compared with those without metastasis. FOXO1 was identified as a down-regulated gene in the minimal overlapping region of the 13q hemizygous deletion in CRCC. Decreased FOXO1 expression was significantly correlated with metastasis and poor survival outcome. Knockdown of FOXO1 inhibited apoptosis after doxorubicin treatment in CRCC cells and reduced the expression of downstream genes involved in cell proliferation (CDKN1B) and survival (BCL2L11). Lower levels of FOXO1 expression were associated with decreased expression of CDKN1B and BCL2L11 in CRCC specimens. We conclude that FOXO1 and TCF7L2 are involved in metastasis and that molecules in these signaling pathways may be targets for diagnostic procedures and therapies for CRCC.

Alpha-1-antitrypsin and complement component C7 are involved in asthma exacerbation.

Asthma is the most common chronic disorder in childhood and asthma exacerbation is an important cause of childhood morbidity and hospitalization. Allergic responses are known to be biased toward T-helper type 2 in asthmatics; however, the pathogenesis of asthma is not simple, and our understanding of the disease mechanism remains incomplete. The aim of the present study was to identify protein expression signatures that reflect acute exacerbation of asthma. Plasma was taken twice from pediatric asthmatic patients, once during asthma exacerbation and once during a stable period. Plasma was also taken from healthy children as a control. The protein profiles of plasma during asthma exacerbation were analyzed by 2-DE and 49 spots were differentially expressed during asthma exacerbation. Thirty-eight of the spots were successfully identified by MALDI-TOF MS. Proteins up- or down-regulated during asthma exacerbation were involved in responses to stress and pathogens, in the complement and coagulation cascades, and in acute-phase responses. Among the differentially expressed proteins, up-regulation of alpha-1-antitrypsin and complement component C7 was confirmed by nephelometry and ELISA. Our present results suggest that protease inhibitors and complement components may be involved in asthma exacerbation, and plasma level of alpha-1-antitrypsin may be a potential biomarker for asthma.