Abnormalities in Copper Status Associated with an Elevated Risk of Parkinson's Phenotype Development

Design of Histidine Sequence-Associated Tripeptide Sequences for Recognition of Copper Ions and Their Application to Live Cells

Copper is central to many enzymes in living organisms, and imbalances in copper levels are linked to various diseases. Therefore, developing probes to detect copper ions is essential. Histidine, especially in the polypeptide sequences at the first three N-terminal positions (His1, His2, and His3), uniquely binds to copper ions. This study introduces three groups of tripeptide probes designed to monitor copper ion levels in living cells and organisms. The results show that tripeptides with histidine at the -2 position, specifically HDQL-2 (Asp-His-Gln-Dansyl), HMFM-2 (Met-His-Phe-Dansyl), and HDMB-2 (Asp-His-Met-Dansyl), exhibit a higher affinity for copper ions. These probes responded quickly to copper ions, demonstrating excellent fluorescence turn-off performance and stable detection within a pH range of 6.0-11.0. The detection limits for fluorescence titration, calculated using the 3σ/k equation, were 17.65 nM (HDQL-2), 18.04 nM (HMFM-2), and 15.50 nM (HDMB-2). Peptide probes are ideal for detecting copper ions in living cells via fluorescence imaging because of their low toxicity and good biocompatibility. The fluorescence intensity decreases as copper ion content changes.

Phage display technology in ecotoxicology: phage display derived unique peptide for copper identification in aquatic samples

BACKGROUND

Ecotoxicology is essential for the evaluation and comprehension of the effects of emergency pollutants (EP) such as heavy metal ions on the natural environment. EPs pose a substantial threat to the health of humans and the proper functioning of the global ecosystem. The primary concern is the exposure of humans and animals to heavy metal ions through contaminated water. The presence of heavy metal ions in drinking water ought to be monitored in accordance with World Health Organization regulations. Among the numerous harmful metal ions, copper ions are responsible for a variety of human diseases.

RESULTS

This study investigates the application of phage display as a screening method for heavy metal toxicological targets, with copper served as the main focus. To identify a variety of Cu-binding M13 phage clones with unique peptides and to assess their affinity for metal ions, the study utilized Escherichia coli as a factories producing recombinant bacteriophages, modified biopanning procedure and an ELISA assay. The research highlights the increasing importance of phage display as a screening tool in ecotoxicology. We synthesized and modified the selected peptide to enable the rapid optical detection of Cu(II) ions in aqueous solutions. By incorporating the dansyl group into a designated peptide sequence, we implemented fluorescence detection assays for real-time measurements. The Cu2+- binding peptide's efficacy was confirmed through spectroscopic measurements, which allowed for real-time detection with rapid response times with high selectivity.

CONCLUSIONS

The phage display technique was successfully applied to develop the fluorescent peptide-based chemosensor that exhibited high selectivity and sensitivity for Cu2+.

Ultra-Selective and Sensitive Fluorescent Chemosensor Based on Phage Display-Derived Peptide with an N-Terminal Cu(II)-Binding Motif

Copper, along with gold, was among the first metals that humans employed. Thus, the copper pollution of the world's water resources is escalating, posing a significant threat to human health and aquatic ecosystems. It is crucial to develop detection technology that is both low-cost and feasible, as well as ultra-selective and sensitive. This study explored the use of the NH2-Xxx-His motif-derived peptide from phage display technology for ultra-selective Cu2+ detection. Various Cu-binding M13 phage clones were isolated, and their affinity and cross-reactivity for different metal ions were determined. A detailed analysis of the amino acid sequence of the unique Cu-binding peptides was employed. For the development of an optical chemosensor, a peptide with an NH2-Xxx-His motif was selected. The dansyl group was incorporated during solid-phase peptide synthesis, and fluorescence detection assays were employed. The efficacy of the Cu2+-binding peptide was verified through spectroscopic measurements. In summary, we developed a highly selective and sensitive fluorescent chemosensor for Cu2+ detection based on a peptide sequence from a phage display library that carries the N-terminal Xxx-His motif.

Experimental models of Parkinson's disease: Challenges and Opportunities

Parkinson's disease (PD) is a widespread neurodegenerative disorder occurs due to the degradation of dopaminergic neurons present in the substantia nigra pars compacta (SNpc). Millions of people are affected by this devastating disorder globally, and the frequency of the condition increases with the increase in the elderly population. A significant amount of progress has been made in acquiring more knowledge about the etiology and the pathogenesis of PD over the past decades. Animal models have been regarded to be a vital tool for the exploration of complex molecular mechanisms involved in PD. Various animals used as models for disease monitoring include vertebrates (zebrafish, rats, mice, guinea pigs, rabbits and monkeys) and invertebrate models (Drosophila, Caenorhabditis elegans). The animal models most relevant for study of PD are neurotoxin induction-based models (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 6-Hydroxydopamine (6-OHDA) and agricultural pesticides (rotenone, paraquat), pharmacological models (reserpine or haloperidol treated rats), genetic models (α-synuclein, Leucine-rich repeat kinase 2 (LRRK2), DJ-1, PINK-1 and Parkin). Several non-mammalian genetic models such as zebrafish, Drosophila and Caenorhabditis elegance have also gained popularity in recent years due to easy genetic manipulation, presence of genes homologous to human PD, and rapid screening of novel therapeutic molecules. In addition, in vitro models (SH-SY5Y, PC12, Lund human mesencephalic (LUHMES) cells, Human induced pluripotent stem cell (iPSC), Neural organoids, organ-on-chip) are also currently in trend providing edge in investigating molecular mechanisms involved in PD as they are derived from PD patients. In this review, we explain the current situation and merits and demerits of the various animal models.

Synthesis of novel polyethyleneimine-capped silver nanoclusters exhibiting ultraviolet-A fluorescence and their application in multiple sensing

Cupric ions (Cu2+), pyrophosphate (PPi), and alkaline phosphatase (ALP) are involved in a variety of biochemical processes such as DNA replication, cellular metabolism and play an important role in human growth and development. It is of great significance to establish a method for the sensitive detection of Cu2+, PPi and ALP. In this work, polyethyleneimine-capped silver nanoclusters (PEI-AgNCs) were successfully synthesized by a one-pot method using hydrazine sulfate as reductant, exhibiting a unique strong fluorescence emission in the near-ultraviolet region at ∼339 nm. Since the fluorescence of PEI-AgNCs can be quenched by Cu2+ through inner filtering effect (IFE), then recovered by competitive binding of pyrophosphate and Cu2+, and later weakened again by catalytic hydrolysis of alkaline phosphatase, a sensitive and selective strategy based on the changes of fluorescence "ON" or "OFF" was established to detect Cu2+, PPi and ALP. The LODs of these three analytes were 36 nM, 0.2 μM, and 0.14 U L-1 at a S/N ratio of 3, respectively. A series of logic gate circuits for sensing cupric ions, pyrophosphate, and alkaline phosphatase were successfully constructed. The established methods have the potential for biosensing and environmental analysis and the specific UV-A fluorescence property of PEI-AgNCs may be helpful in photonic and optical areas.

Unveiling the promising anticancer effect of copper-based compounds: a comprehensive review

Copper is a necessary micronutrient for maintaining the well-being of the human body. The biological activity of organic ligands, especially their anticancer activity, is often enhanced when they coordinate with copper(I) and (II) ions. Copper and its compounds are capable of inducing tumor cell death through various mechanisms of action, including activation of apoptosis signaling pathways by reactive oxygen species (ROS), inhibition of angiogenesis, induction of cuproptosis, and paraptosis. Some of the copper complexes are currently being evaluated in clinical trials for their ability to map tumor hypoxia in various cancers, including locally advanced rectal cancer and bulky tumors. Several studies have shown that copper nanoparticles can be used as effective agents in chemodynamic therapy, phototherapy, hyperthermia, and immunotherapy. Despite the promising anticancer activity of copper-based compounds, their use in clinical trials is subject to certain limitations. Elevated copper concentrations may promote tumor growth, angiogenesis, and metastasis by affecting cellular processes.