SEN1500, a novel oral amyloid-β aggregation inhibitor, attenuates brain pathology in a mouse model of Alzheimer’s disease

Fighting fire with fire: the immune system might be key in our fight against Alzheimer's disease

The ultimate cause of Alzheimer's disease (AD) is still unknown and no disease-modifying treatment exists. Emerging evidence supports the concept that the immune system has a key role in AD pathogenesis. This awareness leads to the idea that specific parts of the immune system must be engaged to ward off the disease. Immunotherapy has dramatically improved the management of several previously untreatable cancers and could hold similar promise as a novel therapy for treating AD. However, before potent immunotherapies can be rationally designed as treatment against AD, we need to fully understand the dynamic interplay between AD and the different parts of our immune system. Accordingly, here we review the most important aspects of both the innate and adaptive immune system in relation to AD pathology. Teaser: Emerging results support the concept that Alzheimer's disease is affected by the inability of the immune system to contain the pathology of the brain. Here, we discuss how we can engage our immune system to fight this devastating disease.

Preparation and characterization of a highly soluble Aβ1-42 peptide variant

Alzheimer's disease (AD) is a progressive neurological disease marked by the accumulation and deposition of misfolded amyloid beta or Abeta (Aβ) peptide. Two species of Aβ peptides are found in amyloid plaques, Aβ_1-40 and Aβ_1-42, with the latter being the more amyloidogenic of the two. Understanding how and why Aβ peptides misfold, oligomerize and form amyloid plaques requires a detailed understanding of their structure and dynamics. The poor solubility and strong aggregation tendencies of Aβ_1-42 has made the isolation and characterization of its different structural isoforms (monomer, dimer, oligomer, amyloid) exceedingly difficult. Furthermore, while synthetic Aβ_1-42 peptides (Aβ₄₂syn) are readily available, the cost of isotopically labeled peptide is substantial, making their characterization by NMR spectroscopy cost prohibitive. Here we describe the design, cloning, high-level production, isotopic labeling and biophysical characterization of a modified (solubility-tagged) Aβ_1-42 variant that exhibits excellent water solubility and shares similar aggregation properties as wildtype Aβ_1-42. Specifically, we attached six lysines (6K) to the C-terminus of native Aβ_1-42 to create a more soluble, monomeric form of Aβ_1-42 called Aβ₄₂C6K. A gene for the Aβ₄₂C6K was designed, synthesized and cloned into Escherichia coli (E. coli) and the peptide was expressed at milligram levels. The Aβ₄₂C6K peptide was characterized using circular dichroism (CD), NMR, electron microscopy and thioflavin T fluorescence. Its ability to form stable monomers, oligomers and fibrils under different conditions was assessed. Our results indicate that Aβ₄₂C6K stays monomeric at high concentrations (unlike Aβ_1-42) and can be induced to oligomerize and form fibrils like Aβ_1-42. Our novel construct could be used to explore the structure and dynamics of Aβ_1-42 as well as the interaction of ligands with Aβ_1-42 via NMR.

Microglia in Alzheimer's disease: A target for immunotherapy

Microglia are resident Mϕs of the CNS that play pleiotropic functions in brain development and homeostasis. Impaired microglial functions are thought to be involved in the onset and progression of various neurodevelopmental and neurodegenerative diseases. Thus, understanding microglia in these settings may indicate new approaches for therapeutic intervention. Here, we review recent evidence implicating microglia in Alzheimer's disease and discuss potential therapeutic strategies targeting microglia and their receptors in this disease.