A tailored tetravalent peptide displays dual functions to inhibit amyloid β production and aggregation

Harnessing the Therapeutic Potential of Peptides for Synergistic Treatment of Alzheimer's Disease by Targeting Aβ Aggregation, Metal-Mediated Aβ Aggregation, Cholinesterase, Tau Degradation, and Oxidative Stress

Alzheimer's disease (AD) is a progressive multifaceted neurodegenerative disease and remains a formidable global health challenge. The current medication for AD gives symptomatic relief and, thus, urges us to look for alternative disease-modifying therapies based on a multitarget directed approach. Looking at the remarkable progress made in peptide drug development in the last decade and the benefits associated with peptides, they offer valuable chemotypes [multitarget directed ligands (MTDLs)] as AD therapeutics. This review recapitulates the current developments made in harnessing peptides as MTDLs in combating AD by targeting multiple key pathways involved in the disease's progression. The peptides hold immense potential and represent a convincing avenue in the pursuit of novel AD therapeutics. While hurdles remain, ongoing research offers hope that peptides may eventually provide a multifaceted approach to combat AD.

Tailored multivalent peptide targeting the B-subunit pentamer of cholera toxin inhibits its intestinal toxicity by inducing aberrant transport of the toxin in cells

Cholera toxin (Ctx) is a major virulence factor produced by Vibrio cholerae that can cause gastrointestinal diseases, including severe watery diarrhea and dehydration, in humans. Ctx binds to target cells through multivalent interactions between its B-subunit pentamer and the receptor ganglioside GM1 present on the cell surface. Here, we identified a series of tetravalent peptides that specifically bind to the receptor-binding region of the B-subunit pentamer using affinity-based screening of multivalent random-peptide libraries. These tetravalent peptides efficiently inhibited not only the cell-elongation phenotype but also the elevated cAMP levels, both of which are induced by Ctx treatment in CHO cells or a human colon carcinoma cell line (Caco-2 cells), respectively. Importantly, one of these peptides, NRR-tet, which was highly efficient in these two activities, markedly inhibited fluid accumulation in the mouse ileum caused by the direct injection of Ctx. In consistent, NRR-tet reduced the extensive Ctx-induced damage of the intestinal villi. After NRR-tet bound to Ctx, the complex was incorporated into the cultured epithelial cells and accumulated in the recycling endosome, affecting the retrograde transport of Ctx from the endosome to the Golgi, which is an essential process for Ctx to exert its toxicity in cells. Thus, NRR-tet may be a novel type of therapeutic agent against cholera, which induces the aberrant transport of Ctx in the intestinal epithelial cells, detoxifying the toxin.

Metabolic Regulations of Smilax china L. against β-Amyloid Toxicity in Caenorhabditis elegans

Smilax china L. (Chinaroot) is a natural herb that has multiple uses, such as being used to make tea and food. Both its roots and leaves have different uses due to their unique components. In this study, we analyzed the extract of S. china. roots using LC-HRMS and evaluated the neuroprotective effects and metabolic regulation of S. china on Caenorhabditis elegans. Chinaroot extract prolonged the life span of healthy nematodes, delayed the paralysis time of transgenic CL4176, and reduced the level of β-amyloid deposition in transgenic CL2006. The comprehensive analysis of metabolomics and qRT-PCR revealed that Chinaroot extract exerted neuroprotective effects through the valine, leucine and isoleucine degradation and fatty acid degradation pathways. Moreover, we first discovered that the expressions of T09B4.8, ech-7, and agxt-1 were linked to the neuroprotective effects of Chinaroot. The material exerted neuroprotective effects by modulating metabolic abnormalities in AD model C. elegans. Our study provides a new foundation for the development of functional food properties and functions.