Citations

Here, we review progress by the Penn Biomarker Core in the Alzheimer's Disease Neuroimaging Initiative (ADNI) toward developing a pathological cerebrospinal fluid (CSF) and plasma biomarker signature for mild Alzheimer's disease (AD) as well as a biomarker profile that predicts conversion of mild cognitive impairment (MCI) and/or normal control subjects to AD. The Penn Biomarker Core also collaborated with other ADNI Cores to integrate data across ADNI to temporally order changes in clinical measures, imaging data, and chemical biomarkers that serve as mileposts and predictors of the conversion of normal control to MCI as well as MCI to AD, and the progression of AD. Initial CSF studies by the ADNI Biomarker Core revealed a pathological CSF biomarker signature of AD defined by the combination of Aβ1‐42 and total tau (T‐tau) that effectively delineates mild AD in the large multisite prospective clinical investigation conducted in ADNI. This signature appears to predict conversion from MCI to AD. Data fusion efforts across ADNI Cores generated a model for the temporal ordering of AD biomarkers which suggests that Aβ amyloid biomarkers become abnormal first, followed by changes in neurodegenerative biomarkers (CSF tau, F‐18 fluorodeoxyglucose‐positron emission tomography, magnetic resonance imaging) with the onset of clinical symptoms. The timing of these changes varies in individual patients due to genetic and environmental factors that increase or decrease an individual's resilience in response to progressive accumulations of AD pathologies. Further studies in ADNI will refine this model and render the biomarkers studied in ADNI more applicable to routine diagnosis and to clinical trials of disease modifying therapies.

A recently identified variant within the fat mass and obesity-associated ( FTO ) gene is carried by 46% of Western Europeans and is associated with an ~1.2 kg higher weight, on average, in adults and an ~1 cm greater waist circumference. With >1 billion overweight and 300 million obese persons worldwide, it is crucial to understand the implications of carrying this very common allele for the health of our aging population. FTO is highly expressed in the brain and elevated body mass index (BMI) is associated with brain atrophy, but it is unknown how the obesity-associated risk allele affects human brain structure. We therefore generated 3D maps of regional brain volume differences in 206 healthy elderly subjects scanned with MRI and genotyped as part of the Alzheimer's Disease Neuroimaging Initiative. We found a pattern of systematic brain volume deficits in carriers of the obesity-associated risk allele versus noncarriers. Relative to structure volumes in the mean template, FTO risk allele carriers versus noncarriers had an average brain volume difference of ~8% in the frontal lobes and 12% in the occipital lobes—these regions also showed significant volume deficits in subjects with higher BMI. These brain differences were not attributable to differences in cholesterol levels, hypertension, or the volume of white matter hyperintensities; which were not detectably higher in FTO risk allele carriers versus noncarriers. These brain maps reveal that a commonly carried susceptibility allele for obesity is associated with structural brain atrophy, with implications for the health of the elderly.

Abstract Aromatase inhibitors play a prominent role in the management of postmenopausal women with endocrine-sensitive breast cancer, but there is large variability in both efficacy and tolerability. The purpose of our study was to define interindividual variation in anastrozole metabolism and pharmacodynamics among patients treated with the approved daily dose of 1 mg in a standard practice setting as adjuvant therapy for resected early breast cancer. This study was performed in 191 women in whom pretreatment and during anastrozole plasma concentrations of estrone (E1), estradiol (E2), estrone conjugates, androstenedione, and testosterone were determined and correlated with plasma concentrations of anastrozole and anastrozole metabolites. There were large interindividual variations in plasma anastrozole and anastrozole metabolite concentrations, as well as pretreatment and postdrug plasma E1, E2, and E1 conjugate and estrogen precursor (androstenedione and testosterone) concentrations. E1 and E2 concentrations were below the lower limit of quantitation (LLQ) in most patients after anastrozole therapy (83% for both), but those with detectable concentrations had a broad range (1.58–45.2 and 0.635–97.0 pg/mL, respectively). E1 conjugates after anastrozole therapy were above the LLQ in most patients (93%), with wide interpatient variability (3.50–2,990 pg/mL). Two patients seemed to extensively metabolize anastrozole and failed to display substantial decreases in estrogens. Acknowledging the potential factor of variable compliance, our results showed large interindividual variation in anastrozole metabolism and its effect on circulating estrogens in postmenopausal patients. These findings may have implications with regard to efficacy and adverse events and may indicate the need to “individualize” therapy with this drug. Cancer Res; 70(8); 3278–86. ©2010 AACR.

Tobacco use is predicted to result in over 1 billion deaths worldwide by the end of the 21 st century. How genetic variation contributes to the observed differential predisposition in the human population to drug dependence is unknown. The zebrafish ( Danio rerio ) is an emerging vertebrate model system for understanding the genetics of behavior. We developed a nicotine behavioral assay in zebrafish and applied it in a forward genetic screen using gene-breaking transposon mutagenesis. We used this method to molecularly characterize bdav /cct8 and hbog /gabbr1.2 as mutations with altered nicotine response. Each have a single human ortholog, identifying two points for potential scientific, diagnostic, and drug development for nicotine biology and cessation therapeutics. We show this insertional method generates mutant alleles that are reversible through Cre-mediated recombination, representing a conditional mutation system for the zebrafish. The combination of this reporter-tagged insertional mutagen approach and zebrafish provides a powerful platform for a rich array of questions amenable to genetic-based scientific inquiry, including the basis of behavior, epigenetics, plasticity, stress, memory, and learning.

Some 5 years ago, it was first discovered that mutations in the gene encoding LRRK2 (leucine-rich repeat protein kinase 2) are tightly linked with a subset of familial PD (Parkinson's disease). Before this genetic association, LRRK2 had never been investigated biochemically. Now it is of utmost importance to establish whether LRRK2 is a bona fide kinase in vitro and in vivo and to understand how mutations of LRRK2 lead to the specific loss of dopaminergic neurons in the substantia nigra to cause PD. In spite of tremendous efforts in the research community, there is no consensus with regard to the magnitude of the enzymatic activity of LRRK2 mutant forms that segregate with PD owing, in part, to the lack of a highly sensitive kinase assay system, and it is still unclear whether an abnormal increase in kinase activity is responsible for LRRK2-associated PD. As described in this issue of the Biochemical Journal, Nichols et al. have developed an extensive set of molecular tools, including an optimized peptide substrate for determining in vitro kinase activity of LRRK2, a set of kinase inhibitors that can be used to explore LRRK2 substrate specificity and biology, a much-needed murine-specific antibody for immunoprecipation, and efficient gene-silencing approaches. In the present commentary, we discuss some of the components of this new LRRK2 biochemical toolbox and how they can be used to better understand this enigmatic kinase.

Background Different cerebrospinal fluid (CSF) amyloid-beta 1–42 (A β 1–42 ), total Tau (Tau) and Tau phosphorylated at threonine 181 (P-Tau) levels are reported, but currently there is a lack of quality control programmes. The aim of this study was to compare the measurements of these CSF biomarkers, between and within centres. Methods Three CSF-pool samples were distributed to 13 laboratories in 2004 and the same samples were again distributed to 18 laboratories in 2008. In 2004 six laboratories measured A β 1–42 , Tau and P-Tau and seven laboratories measured one or two of these marker(s) by enzyme-linked immunosorbent assays (ELISAs). In 2008, 12 laboratories measured all three markers, three laboratories measured one or two marker(s) by ELISAs and three laboratories measured the markers by Luminex. Results In 2004, the ELISA intercentre coefficients of variance (interCV) were 31%, 21% and 13% for A β 1–42 , Tau and P-Tau, respectively. These were 37%, 16% and 15%, respectively, in 2008. When we restricted the analysis to the Innotest ® ( N = 13) for A β 1–42 , lower interCV were calculated (22%). The centres that participated in both years ( N = 9) showed interCVs of 21%, 15% and 9% and intra-centre coefficients (intraCV) of variance of 25%,18% and 7% in 2008. Conclusions The highest variability was found for A β 1–42 . The variabilities for Tau and P-Tau were lower in both years. The centres that participated in both years showed a high intraCV comparable to their interCV, indicating that there is not only a high variation between but also within centres. Besides a uniform standardization of (pre)analytical procedures, the same assay should be used to decrease the inter/intracentre variation.

Abstract Morpholino oligonucleotides are the most common anti-sense “knockdown” technique used in zebrafish ( Danio rerio ). This review discusses common practices for the design, preparation, and deployment of morpholinos in this vertebrate model system. Off-targeting effects of morpholinos are discussed as well as method to minimize this potentially confounding variable via co-injection of a tP53-targeting morpholino. Finally, new uses of morpholinos are summarized and contextualized with respect to the complementary, DNA-based knockout technologies recently developed for zebrafish.