DNA methylation analysis on purified neurons and glia dissects age and Alzheimer's disease-specific changes in the human cortex.

BACKGROUND: Epigenome-wide association studies (EWAS) based on human brain samples allow a deep and direct understanding of epigenetic dysregulation in Alzheimer's disease (AD). However, strong variation of cell-type proportions across brain tissue samples represents a significant source of data noise. Here, we report the first EWAS based on sorted neuronal and non-neuronal (mostly glia) nuclei from postmortem human brain tissues. RESULTS: We show that cell sorting strongly enhances the robust detection of disease-related DNA methylation changes even in a relatively small cohort. We identify numerous genes with cell-type-specific methylation signatures and document differential methylation dynamics associated with aging specifically in neurons such as CLU, SYNJ2 and NCOR2 or in glia RAI1,CXXC5 and INPP5A. Further, we found neuron or glia-specific associations with AD Braak stage progression at genes such as MCF2L, ANK1, MAP2, LRRC8B, STK32C and S100B. A comparison of our study with previous tissue-based EWAS validates multiple AD-associated DNA methylation signals and additionally specifies their origin to neuron, e.g., HOXA3 or glia (ANK1). In a meta-analysis, we reveal two novel previously unrecognized methylation changes at the key AD risk genes APP and ADAM17. CONCLUSIONS: Our data highlight the complex interplay between disease, age and cell-type-specific methylation changes in AD risk genes thus offering new perspectives for the validation and interpretation of large EWAS results.

An albumin-based tumor-targeted oxaliplatin prodrug with distinctly improved anticancer activity in vivo.

The design of targeted platinum(iv) prodrugs is a very promising approach to enhance the low selectivity of platinum(ii) drugs towards cancerous tissue in order to reduce the impact on healthy tissue and, consequently, the often severe side-effects. Herein, we report a set of mono-functionalized cis- and oxaliplatin-based platinum(iv) complexes bearing a maleimide moiety, which allows selective binding to serum albumin in the bloodstream. This leads not only to a prolonged plasma half-life by avoidance of fast renal clearance, but also to preferential accumulation of the drug in the tumor tissue due to the EPR-effect. Additionally, analogous succinimide-functionalized derivatives were prepared to verify the influence of the maleimide moiety. First experiments showed that all the maleimide compounds are stable and also possess good albumin-binding properties in whole serum. Further analytical studies on in vivo samples proved the highly increased plasma half-life, as well as tumor accumulation of the maleimide-functionalized substances. In vivo antitumor experiments with CT-26-bearing mice showed that, in contrast to the cisplatin derivatives, the oxaliplatin-based complexes had exceptionally better activity than the free drug resulting in the cure of the majority of treated mice. Subsequent analysis suggested that a distinctly faster reduction as well as reduced tumor accumulation of the cisplatin derivative might explain the worse performance compared to the oxaliplatin(iv) complexes. Taken together, a novel lead platinum(iv) complex with outstanding antitumor activity is presented, which will now be further developed towards clinical phase I trials.

Altered Long Noncoding RNA Expression Precedes the Course of Parkinson's Disease-a Preliminary Report.

Parkinson's disease (PD) is a slowly progressing neurodegenerative disorder that affects approximately seven million patients worldwide. Despite intensive research, the molecular mechanisms initiating and promoting PD are still unknown. However, it is assumed that environmental factors trigger PD. Recent research demonstrated that long noncoding RNAs (lncRNA) interfere in transcriptional and translational processes modulating gene expression reflecting environmental influences. Nevertheless, there is no systematic analysis available that investigates the impact of lncRNAs on PD. In the current study, we performed a comprehensive analysis on expression levels of 90 well-annotated lncRNAs in 30 brain specimens deriving from 20 PD patients and 10 controls as a preliminary report on the significance of lncRNAs in PD. Expression profiling of lncRNAs revealed that five lncRNAs are significantly differentially expressed in PD. While H19 upstream conserved 1 and 2 is significantly downregulated in PD, lincRNA-p21, Malat1, SNHG1, and TncRNA are significantly upregulated. An analysis on expression levels and PD stages revealed that the identified dysregulated lncRNA are altered already in early disease stage and that they precede the course of PD. In summary, this is the first comprehensive analysis on lncRNAs in PD revealing significantly altered lncRNAs. Additionally, we found that lncRNA dysregulations precede the course of the disease. Thus, the five newly identified lncRNAs may serve as potential new biomarkers appropriate even in early PD. They may be used in monitoring disease progression and they may serve as potential new targets for novel therapeutic approaches.

Targeting a Targeted Drug: An Approach Toward Hypoxia-Activatable Tyrosine Kinase Inhibitor Prodrugs.

Tyrosine kinase inhibitors (TKIs), which have revolutionized cancer therapy over the past 15 years, are limited in their clinical application due to serious side effects. Therefore, we converted two approved TKIs (sunitinib and erlotinib) into 2-nitroimidazole-based hypoxia-activatable prodrugs. Kinetics studies showed very different stabilities over 24 h; however, fast reductive activation via E. coli nitroreductase could be confirmed for both panels. The anticancer activity and signaling inhibition of the compounds against various human cancer cell lines were evaluated in cell culture. These data, together with molecular docking simulations, revealed distinct differences in the impact of structural modifications on drug binding to the enzymes: whereas the catalytic pocket of the epidermal growth factor receptor (EGFR) accepted all new erlotinib derivatives, the vascular endothelial growth factor receptor (VEGFR)-inhibitory potential in the case of the sunitinib prodrugs was dramatically diminished by derivatization. In line, hypoxia dependency of ERK signaling inhibition was observed with the sunitinib prodrugs, while oxygen levels had no impact on the activity of the erlotinib derivatives. Overall, proof of principle could be shown for this concept, and the results obtained are an important basis for the future development of tyrosine kinase inhibitor prodrugs.