S100 Proteins in Alzheimer’s Disease

S100 proteins are calcium-binding proteins that regulate several processes associated with Alzheimer’s disease (AD) but whose contribution and direct involvement in disease pathophysiology remains to be fully established. Due to neuroinflammation in AD patients, the levels of several S100 proteins are increased in the brain and some S100s play roles related to the processing of the amyloid precursor protein, regulation of amyloid beta peptide (Aβ) levels and Tau phosphorylation. S100 proteins are found associated with protein inclusions, either within plaques or as isolated S100-positive puncta, which suggests an active role in the formation of amyloid aggregates. Indeed, interactions between S100 proteins and aggregating Aβ indicate regulatory roles over the aggregation process, which may either delay or aggravate aggregation, depending on disease stage and relative S100 and Aβ levels. Additionally, S100s are also known to influence AD-related signaling pathways and levels of other cytokines. Recent evidence also suggests that metal-ligation by S100 proteins influences trace metal homeostasis in the brain, particularly of zinc, which is also a major deregulated process in AD. Altogether, this evidence strongly suggests a role of S100 proteins as key players in several AD-linked physiopathological processes, which we discuss in this review

Bacteriophages a bio sustainable solution to tackle Alzheimer´s disease

Introduction: Amyloid-beta (AB) is a prime suspect to cause Alzheimers disease (AD), an irreversible, progressive and age-dependent neurodegenerative disorder affecting millions of people worldwide. An accumulation of AB in the brain leads to its aggregation into soluble oligomeric and fibrillar clusters, which are the culprits to impair synaptic function and memory formation in mice models. Currently, we lack diagnostic tools to detect AB oligomers (ABOs) in the brain, all the methods used provide a late diagnosis when there are already symptoms. Moreover, the existence of the blood-brain-barrier (BBB) is the major bottleneck for reaching the brain. To overcome this, bacteriophages (phages: bacterial viruses) are a solution, once they posses the capacity to cross the BBB. Aims: Hence, our main goals were the development of a solution to 1) detect ABOs in the brain and monitor AD progression and 2) delay or prevent the onset of the symptoms. Methods: We resorted to phage engineering with AB-targeting peptides described to recognize ABOs and fibrils with high affinity. These were tested for their capacity to detect ABOs in tissues samples and their effect on AB aggregation. Results: The engineered phages are able to detect the early and toxic forms of AB in brain tissue of APP/PS1 transgenic mice and human donors. Moreover, these phages also possess a high therapeutic potential by inhibiting the aggregation process of AB. Conclusion: We provide a highly versatile bio-inspired solution based on phages displaying AB peptides to detect early soluble AB oligomers in the brain, and possibly prevent, or delay, the onset of the symptoms, consequently inhibiting AD progression.The authors thank the Project EARLY - Phage towards initial amyloid-beta funded by TecMinho through the iProof initiative, in the scope of the project UI-Transfer, co-financed by COMPETE 2020, through Fundo Europeu de Desenvolvimento Regional (FEDER). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, and by LABBELS – Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020, center grant UID/MULTI/04046/2020 (to BioISI), PhD fellowship SFRH/BD/101171/2014 (to J.S.C.), and by Alzheimer Nederland (H.W.K.).info:eu-repo/semantics/publishedVersio

M13 phage grafted with peptide motifs as a tool to detect amyloid- oligomers in brain tissue

Oligomeric clusters of amyloid- (A) are one of the major biomarkers for Alzheimers disease (AD). However, proficient methods to detect A-oligomers in brain tissue are lacking. Here we show that synthetic M13 bacteriophages displaying A-derived peptides on their surface preferentially interact with A-oligomers. When exposed to brain tissue isolated from APP/PS1-transgenic mice, these bacteriophages detect small-sized A-aggregates in hippocampus at an early age, prior to the occurrence of A-plaques. Similarly, the bacteriophages reveal the presence of such small A-aggregates in post-mortem hippocampus tissue of ADpatients. These results advocate bacteriophages displaying A-peptides as a convenient and low-cost tool to identify A-oligomers in post-mortem brain tissue of AD-model mice and AD patients.FCT -Fundação para a Ciência e a Tecnologia(SFRH/BD/101171/2014)info:eu-repo/semantics/publishedVersio

Glucosylpolyphenols as Inhibitors of Aβ-Induced Fyn Kinase Activation and Tau Phosphorylation: Synthesis, Membrane Permeability, and Exploratory Target Assessment within the Scope of Type 2 Diabetes and Alzheimer's Disease

Despite the rapidly increasing number of patients suffering from type 2 diabetes, Alzheimer's disease, and diabetes-induced dementia, there are no disease-modifying therapies that are able to prevent or block disease progress. In this work, we investigate the potential of nature-inspired glucosylpolyphenols against relevant targets, including islet amyloid polypeptide, glucosidases, and cholinesterases. Moreover, with the premise of Fyn kinase as a paradigm-shifting target in Alzheimer's drug discovery, we explore glucosylpolyphenols as blockers of Aβ-induced Fyn kinase activation while looking into downstream effects leading to Tau hyperphosphorylation. Several compounds inhibit Aβ-induced Fyn kinase activation and decrease pTau levels at 10 μM concentration, particularly the per-O-methylated glucosylacetophloroglucinol and the 4-glucosylcatechol dibenzoate, the latter inhibiting also butyrylcholinesterase and β-glucosidase. Both compounds are nontoxic with ideal pharmacokinetic properties for further development. This work ultimately highlights the multitarget nature, fine structural tuning capacity, and valuable therapeutic significance of glucosylpolyphenols in the context of these metabolic and neurodegenerative disorders.European Commission GA 612347Fundação para a Ciência e a Tecnologia SFRH/BD/93170/2013, SFRH/BD/116614/2016, PD/BD/142847/2018, SFRH/BD/145600/2019, CEECIND/03414/2018, CEECIND/02300/2017, UIDB/00100/2020, UIDB/04046/2020, UIDB/04378/2020, IF/00780/2015Gobierno de España CTQ2016-78703-PJunta de Andalucía FQM13

Small Molecules Present in the Cerebrospinal Fluid Metabolome Influence Superoxide Dismutase 1 Aggregation

Superoxide dismutase 1 (SOD1) aggregation is one of the pathological markers of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. The underlying molecular grounds of SOD1 pathologic aggregation remains obscure as mutations alone are not exclusively the cause for the formation of protein inclusions. Thus, other components in the cell environment likely play a key role in triggering SOD1 toxic aggregation in ALS. Recently, it was found that ALS patients present a specific altered metabolomic profile in the cerebrospinal fluid (CSF) where SOD1 is also present and potentially interacts with metabolites. Here we have investigated how some of these small molecules affect apoSOD1 structure and aggregation propensity. Our results show that as co-solvents, the tested small molecules do not affect apoSOD1 thermal stability but do influence its tertiary interactions and dynamics, as evidenced by combined biophysical analysis and proteolytic susceptibility. Moreover, these compounds influence apoSOD1 aggregation, decreasing nucleation time and promoting the formation of larger and less soluble aggregates, and in some cases polymeric assemblies apparently composed by spherical species resembling the soluble native protein. We conclude that some components of the ALS metabolome that shape the chemical environment in the CSF may influence apoSOD1 conformers and aggregation

M13 bacteriophages displaying peptide motifs targeting amyloid- eta, methods and uses thereof

International Patent: WO/2024/033903The present disclosure relates to an engineered M13 bacteriophage displaying amyloidogenic peptide motifs from amyloid beta 42 (A42) at its surface. The present disclosure further relates to the use of the disclosed engineered M13 bacteriophage for detecting early species of A, namely oligomeric and fibrillar A, and preventing its aggregation promoting the inhibition of the progression of Alzheimer's disease and thus contributing to the treatment of this neurodegenerative disorder.info:eu-repo/semantics/publishedVersio

Targeting S100B with Peptides Encoding Intrinsic Aggregation-Prone Sequence Segments

S100 proteins assume a diversity of oligomeric states including large order self-assemblies, with an impact on protein structure and function. Previous work has uncovered that S100 proteins, including S100B, are prone to undergo β-aggregation under destabilizing conditions. This propensity is encoded in aggregation-prone regions (APR) mainly located in segments at the homodimer interface, and which are therefore mostly shielded from the solvent and from deleterious interactions, under native conditions. As in other systems, this characteristic may be used to develop peptides with pharmacological potential that selectively induce the aggregation of S100B through homotypic interactions with its APRs, resulting in functional inhibition through a loss of function. Here we report initial studies towards this goal. We applied the TANGO algorithm to identify specific APR segments in S100B helix IV and used this information to design and synthesize S100B-derived APR peptides. We then combined fluorescence spectroscopy, transmission electron microscopy, biolayer interferometry, and aggregation kinetics and determined that the synthetic peptides have strong aggregation propensity, interact with S100B, and may promote co-aggregation reactions. In this framework, we discuss the considerable potential of such APR-derived peptides to act pharmacologically over S100B in numerous physiological and pathological conditions, for instance as modifiers of the S100B interactome or as promoters of S100B inactivation by selective aggregation

Up-regulation of neuropeptide Y levels and modulation of glutamate release through neuropeptide Y receptors in the hippocampus of kainate-induced epileptic rats

Kainate-induced epilepsy has been shown to be associated with increased levels of neuropeptide Y (NPY) in the rat hippocampus. However, there is no information on how increased levels of this peptide might modulate excitation in kainate-induced epilepsy. In this work, we investigated the modulation of glutamate release by NPY receptors in hippocampal synaptosomes isolated from epileptic rats. In the acute phase of epilepsy, a transient decrease in the efficiency of NPY and selective NPY receptor agonists in inhibiting glutamate release was observed. Moreover, in the chronic epileptic hippocampus, a decrease in the efficiency of NPY and the Y2 receptor agonist, NPY13-36, was also found. Simultaneously, we observed that the epileptic hippocampus expresses higher levels of NPY, which may account for an increased basal inhibition of glutamate release. Consistently, the blockade of Y2 receptors increased KCl-evoked glutamate release, and there was an increase in Y2 receptor mRNA levels 30 days after kainic acid injection, suggesting a basal effect of NPY through Y2 receptors. Taken together, these results indicate that an increased function of the NPY modulatory system in the epileptic hippocampus may contribute to basal inhibition of glutamate release and control hyperexcitability

Zinc Binding to Tau Influences Aggregation Kineticsand Oligomer Distribution

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