Nanolithium, a New Treatment Approach to Alzheimer's Disease: A Review of Existing Evidence and Clinical Perspectives.

Lithium has been approved and used for several decades in the treatment of psychiatric disorders, and its potential effect in neurodegenerative diseases has been subject to increasing research interest in recent years. Nanolithium is a new experimental product using a novel drug-delivery technology (Aonys®), which optimizes its bioavailability while reducing its toxicity profile. Therapeutic doses of lithium used in Nanolithium are more than 50 times lower than the minimal dose of classical lithium salts. In this review we report data from non-clinical pharmacology studies supporting Nanolithium efficacy and the mechanism of action in Alzheimer's disease. GSK-3ß inhibition is thought to be central to Nanolithium's mechanism of action, triggering a reduction of the production of toxic amyloid plaques and decrease in tau hyperphosphorylation, which could potentially benefit both neuropsychiatric symptoms and cognitive decline. We then summarize outcomes from non-clinical proof-of-concept studies. These data supported the initiation of a currently ongoing phase II proof-of-concept study to evaluate the safety and efficacy of Nanolithium in patients with mild-to-severe Alzheimer's disease. We highlight key aspects of the study design. We finish this review with a discussion on the potential place of Nanolithium in the current and future Alzheimer's disease treatment landscape.

Effect of pH and salt bridges on structural assembly: molecular structures of the monomer and intertwined dimer of the Eps8 SH3 domain.

The SH3 domain of Eps8 was previously found to form an intertwined, domain-swapped dimer. We report here a monomeric structure of the EPS8 SH3 domain obtained from crystals grown at low pH, as well as an improved domain-swapped dimer structure at 1.8 A resolution. In the domain-swapped dimer the asymmetric unit contains two "hybrid-monomers." In the low pH form there are two independently folded SH3 molecules per asymmetric unit. The formation of intermolecular salt bridges is thought to be the reason for the formation of the dimer. On the basis of the monomer SH3 structure, it is argued that Eps8 SH3 should, in principle, bind to peptides containing a PxxP motif. Recently it was reported that Eps8 SH3 binds to a peptide with a PxxDY motif. Because the "SH3 fold" is conserved, alternate binding sites may be possible for the PxxDY motif to bind. The strand exchange or domain swap occurs at the n-src loops because the n-src loops are flexible. The thermal b-factors also indicate the flexible nature of n-src loops and a possible handle for domain swap initiation. Despite the loop swapping, the typical SH3 fold in both forms is conserved structurally. The interface of the acidic form of SH3 is stabilized by a tetragonal network of water molecules above hydrophobic residues. The intertwined dimer interface is stabilized by hydrophobic and aromatic stacking interactions in the core and by hydrophilic interactions on the surface.

Thousands of proteins likely to have long disordered regions.

Neural network predictors of protein disorder using primary sequence information were developed and applied to the Swiss Protein Database. More than 15,000 proteins were predicted to contain disordered regions of at least 40 consecutive amino acids, with more than 1,000 having especially high scores indicating disorder. These results support proposals that consideration of structure-activity relationships in proteins need to be broadened to include unfolded or disordered protein.

Protein disorder and the evolution of molecular recognition: theory, predictions and observations.

Observations going back more than 20 years show that regions in proteins with disordered backbones can play roles in their binding to other molecules; typically, the disordered regions become ordered upon complex formation. Thought-experiments with Schulz Diagrams, which are defined herein, suggest that disorder-to-order transitions are required for natural selection to operate separately on affinity and specificity. Separation of affinity and specificity may be essential for fine-tuning the molecular interaction networks that comprise the living state. For low affinity, high specificity interactions, our analysis suggests that natural selection would parse the amino acids conferring flexibility in the unbound state from those conferring specificity in the bound state. For high affinity, low specificity or for high affinity, multiple specificity interactions, our analysis suggests that the disorder-to-order transitions enable alternative packing interactions between side chains to accommodate the different binding targets. Disorder-to-order transitions upon binding also have significant kinetic implications as well, by having complex effects on both on- and off-rates. Current data are insufficient to decide on these proposals, but sequence and structure analysis on two examples support further investigations of the role of disorder-to-order transitions upon binding.