Shedding Light on the Molecular Pathology of Amyloid Plaques in Transgenic Alzheimer’s Disease Mice Using Multimodal MALDI Imaging Mass Spectrometry

Senile plaques formed by aggregated amyloid β peptides are one of the major pathological hallmarks of Alzheimer’s disease (AD) which have been suggested to be the primary influence triggering the AD pathogenesis and the rest of the disease process. However, neurotoxic Aβ aggregation and progression are associated with a wide range of enigmatic biochemical, biophysical and genetic processes. MALDI imaging mass spectrometry (IMS) is a label-free method to elucidate the spatial distribution patterns of intact molecules in biological tissue sections. In this communication, we utilized multimodal MALDI-IMS analysis on 18 month old transgenic AD mice (tgArcSwe) brain tissue sections to enhance molecular information correlated to individual amyloid aggregates on the very same tissue section. Dual polarity MALDI-IMS analysis of lipids on the same pixel points revealed high throughput lipid molecular information including sphingolipids, phospholipids, and lysophospholipids which can be correlated to the ion images of individual amyloid β peptide isoforms at high spatial resolutions (10 μm). Further, multivariate image analysis was applied in order to probe the multimodal MALDI-IMS data in an unbiased way which verified the correlative accumulations of lipid species with dual polarity and Aβ peptides. This was followed by the lipid fragmentation obtained directly on plaque aggregates at higher laser pulse energies which provided tandem MS information useful for structural elucidation of several lipid species. Majority of the amyloid plaque-associated alterations of lipid species are for the first time reported here. The significance of this technique is that it allows correlating the biological discussion of all detected plaque-associated molecules to the very same individual amyloid plaques which can give novel insights into the molecular pathology of even a single amyloid plaque microenvironment in a specific brain region. Therefore, this allowed us to interpret the possible roles of lipids and amyloid peptides in amyloid plaque-associated pathological events such as focal demyelination, autophagic/lysosomal dysfunction, astrogliosis, inflammation, oxidative stress, and cell death

Correlations between tau and disease progression in Huntington’s disease.

<p>Tau does not correlate with (<b>A</b>) 5-year probalility of disease onset but correlations with (<b>B</b>) disease burden, (<b>C</b>) total functional capacity, and (<b>D</b>) total motor score were significant. ○ Premanifest gene expansion carrier • Manifest Huntington’s disease.</p

Characteristics of the study population.

<p>Characteristics of the study population.</p

Comparing the correlations of neurofilament light and tau with cognitive test scores.

<p>Neurofilament light (NFL) has stronger correlations with clinical scores like (<b>A</b>) stroop interferens, and (<b>B</b>) category fluency, compared with (<b>C</b> and <b>D</b>) tau. ○ Premanifest gene expansion carrier • Manifest Huntington’s disease.</p

Spearman correlations between NFL and clinical test scores adjusted for age and adjusted for disease burden compared with the direct correlations.

<p>Spearman correlations between NFL and clinical test scores adjusted for age and adjusted for disease burden compared with the direct correlations.</p

Correlations between NFL and disease progression in Huntington’s disease.

<p>(<b>A</b>) Neurofilament light (NFL) and tau levels are significantly correlated. NFL correlates positively with (<b>B</b>) disease burden and (<b>C</b>) 5-year probability of disease onset but negatively with (<b>D</b>) total functional capacity. ○ Premanifest gene expansion carrier • Manifest Huntington’s disease.</p

Biomarker concentrations in cerebrospinal fluid and plasma.⁴

1<p>Test A: 1–6 days after last bout;</p>2<p>Test B: No boxing for at least 14 days.</p>3<p>According to pNFH, the result from one of the controls was destroyed.</p>4<p>Aβ <b>_1-42</b> was collected from plasma.</p

Peptidome Analysis of Cerebrospinal Fluid by LC-MALDI MS

<div><p>We report on the analysis of endogenous peptides in cerebrospinal fluid (CSF) by mass spectrometry. A method was developed for preparation of peptide extracts from CSF. Analysis of the extracts by offline LC-MALDI MS resulted in the detection of 3,000–4,000 peptide-like features. Out of these, 730 peptides were identified by MS/MS. The majority of these peptides have not been previously reported in CSF. The identified peptides were found to originate from 104 proteins, of which several have been reported to be involved in different disorders of the central nervous system. These results support the notion that CSF peptidomics may be viable complement to proteomics in the search of biomarkers of CNS disorders.</p> </div

Blood-based cerebral biomarkers in preeclampsia: Plasma concentrations of NfL, tau, S100B and NSE during pregnancy in women who later develop preeclampsia - A nested case control study

<div><p>Objective</p><p>To evaluate if concentrations of the neuronal proteins neurofilament light chain and tau are changed in women developing preeclampsia and to evaluate the ability of a combination of neurofilament light chain, tau, S100B and neuron specific enolase in identifying neurologic impairment before diagnosis of preeclampsia.</p><p>Methods</p><p>A nested case-control study within a longitudinal study cohort was performed. 469 healthy pregnant women were enrolled between 2004–2007 and plasma samples were collected at gestational weeks 10, 25, 28, 33 and 37. Plasma concentrations of tau and neurofilament light chain were analyzed in 16 women who eventually developed preeclampsia and 36 controls throughout pregnancy with single molecule array (Simoa) method and compared within and between groups. S100B and NSE had been analyzed previously in the same study population. A statistical model with receiving characteristic operation curve was constructed with the four biomarkers combined.</p><p>Results</p><p>Plasma concentrations of neurofilament light chain were significantly increased in women who developed preeclampsia in gestational week 33 (11.85 ng/L, IQR 7.48–39.93 <i>vs</i> 6.80 ng/L, IQR 5.65–11.40) and 37 (22.15 ng/L, IQR 10.93–35.30 <i>vs</i> 8.40 ng/L, IQR 6.40–14.30) and for tau in gestational week 37 (4.33 ng/L, IQR 3.97–12.83 <i>vs</i> 3.77 ng/L, IQR 1.91–5.25) in contrast to healthy controls. A combined model for preeclampsia with tau, neurofilament light chain, S100B and neuron specific enolase in gestational week 25 displayed an area under the curve of 0.77, in week 28 it was 0.75, in week 33 it was 0.89 and in week 37 it was 0.83. Median week for diagnosis of preeclampsia was at 38 weeks of gestation.</p><p>Conclusion</p><p>Concentrations of both tau and neurofilament light chain are increased in the end of pregnancy in women developing preeclampsia in contrast to healthy pregnancies. Cerebral biomarkers might reflect cerebral involvement before onset of disease.</p></div

Boxer's details and risk factors for brain injury.

1<p>1–6 days after a bout;</p>2<p>A rest period of a minimum of 14 days;</p>3<p>Boxing at age 10–14 years without hard punches;</p>4<p><u>R</u>eferee <u>S</u>tops <u>C</u>ontest due to hard blows against <u>h</u>ead;</p>5<p>Three experts graded the boxers 1 to 5, independently, (from low to high head trauma exposure considering total boxing career);</p>6<p>The boxers scored their last fight as easy, intermediate or tough;</p>7<p>Number of bouts in a row (maximum one per day) for the test A;</p>8<p>If a boxer experienced some sequelae after the last bout;</p>**<p>Boxers with increased risk for MTBI.</p