A Review on Mitochondrial Derived Peptide Humanin and Small Humanin-Like Peptides and Their Therapeutic Strategies

Assessing the therapeutic potential of KK14 peptide derived from Cyprinus Carpio in reducing intercellular ROS levels in oxidative Stress-Induced In vivo zebrafish larvae model: An integrated bioinformatics, antioxidant, and neuroprotective analysis

H2O2 is a significant reactive oxygen species (ROS) that hinders redox-mediated processes and contributes to oxidative stress and neurodegenerative disorders. Oxidative stress causes impairment of cell macromolecules, which results in cell dysfunction and neurodegeneration. Alzheimer's disease and other neurodegenerative diseases are serious conditions linked to oxidative stress. Antioxidant treatment approaches are a novel and successful strategy for decreasing neurodegeneration and reducing oxidative stress. This study explored the antioxidant and neuroprotective characteristics of KK14 peptide synthesized from LEAP 2B (liver-expressed antimicrobial peptide-2B) derived from Cyprinus carpio L. Molecular docking studies were used to assess the antioxidant properties of KK14. The peptide at concentrations 5-45 μM was examined by using in vitro and in vivo assessment. Analysis was done on the developmental and neuroprotective potential of KK14 peptide treatment in H2O2-exposed zebrafish larvae which showed Nonlethal deformities. KK14 improves antioxidant enzyme activity like catalase and superoxide dismutase. Furthermore, it reduces neuronal damage by lowering lipid peroxidation and nitric oxide generation while increasing acetylcholinesterase activity. It improved the changes in swimming behavior and the cognitive damage produced by exposure to H2O2. To further substantiate the neuroprotective potential of KK14, intracellular ROS levels in zebrafish larvae were assessed. This led to a reduction in ROS levels and diminished lipid peroxidation. The KK14 has upregulated the antioxidant genes against oxidative stress. Overall, this study proved the strong antioxidant activity of KK14, suggesting its potential as a strong therapeutic option for neurological disorders caused by oxidative stress.

Comparative analysis of formyl peptide receptor 1 and formyl peptide receptor 2 reveals shared and preserved signalling profiles

BACKGROUND AND PURPOSE

The pattern recognition receptors, formyl peptide receptors, FPR1 and FPR2, are G protein-coupled receptors that recognize many different pathogen- and host-derived ligands. While FPR1 conveys pro-inflammatory signals, FPR2 is linked with pro-resolving outcomes. To analyse how the two very similar FPRs exert opposite effects in modulating inflammatory responses despite their high homology, a shared expression profile on immune cells and an overlapping ligand repertoire, we questioned whether the signalling profile differs between these two receptors.

EXPERIMENTAL APPROACH

We deduced EC50 and Emax values for synthetic, pathogen-derived and host-derived peptide agonists for both FPR1 and FPR2 and analysed them within the framework of biased signalling. We furthermore investigated whether FPR isoform-specific agonists affect the ex vivo lifespan of human neutrophils.

KEY RESULTS

The FPRs share a core signature across signalling pathways. Whereas the synthetic WKYMVm and formylated peptides acted as potent agonists at FPR1, and at FPR2, only WKYMVm was a full agonist. Natural FPR2 agonists, irrespective of N-terminal formylation, displayed lower activity ratios, suggesting an underutilized signalling potential of this receptor. FPR2 agonism did not counteract LPS-induced neutrophil survival, indicating that FPR2 activation per se is not linked with a pro-resolving function.

CONCLUSION AND IMPLICATIONS

Activation of FPR1 and FPR2 by a representative agonist panel revealed a lack of a receptor-specific signalling texture, challenging assumptions about distinct inflammatory profiles linked to specific receptor isoforms, signalling patterns or agonist classes. These conclusions are restricted to the specific agonists and signalling pathways examined.

Exploring the neuroprotective potential of KC14 peptide from Cyprinus carpio against oxidative stress-induced neurodegeneration by regulating antioxidant mechanism

BACKGROUND

Oxidative stress, a condition characterized by excessive production of reactive oxygen species (ROS), can cause significant damage to cellular macromolecules, leading to neurodegeneration. This underscores the need for effective antioxidant therapies that can mitigate oxidative stress and its associated neurodegenerative effects. KC14 peptide derived from liver-expressed antimicrobial peptide-2 A (LEAP 2 A) from Cyprinus carpio L. has been identified as a potential therapeutic agent. This study focuses on the antioxidant and neuroprotective properties of the KC14 peptide is to evaluate its effectiveness against oxidative stress and neurodegeneration.

METHODS

The antioxidant capabilities of KC14 were initially assessed through in silico docking studies, which predicted its potential to interact with oxidative stress-related targets. Subsequently, the peptide was tested at concentrations ranging from 5 to 45 µM in both in vitro and in vivo experiments. In vivo studies involved treating H2O2-induced zebrafish larvae with KC14 peptide to analyze its effects on oxidative stress and neuroprotection.

RESULTS

KC14 peptide showed a protective effect against the developmental malformations caused by H2O2 stress, restored antioxidant enzyme activity, reduced neuronal damage, and lowered lipid peroxidation and nitric oxide levels in H2O2-induced larvae. It enhanced acetylcholinesterase activity and significantly reduced intracellular ROS levels (p < 0.05) dose-dependently. Gene expression studies showed up-regulation of antioxidant genes with KC14 treatment under H2O2 stress.

CONCLUSIONS

This study highlights the potent antioxidant activity of KC14 and its ability to confer neuroprotection against oxidative stress can provide a novel therapeutic agent for combating neurodegenerative diseases induced by oxidative stress.

Neuroprotective Action of Humanin and Humanin Analogues: Research Findings and Perspectives

Humanin is a 24-mer peptide first reported in the early 2000s as a new neuroprotective/cytoprotective factor rescuing neuronal cells from death induced by various Alzheimer's disease-associated insults. Nowadays it is known that humanin belongs to the novel class of the so-called mitochondrial-derived peptides (which are encoded by mitochondrial DNA) and has been shown to exert beneficial cytoprotective effects in a series of in vitro and/or in vivo experimental models of human diseases, including not only neurodegenerative disorders but other human diseases as well (e.g., age-related macular degeneration, cardiovascular diseases, or diabetes mellitus). This review article is focused on the presentation of recent in vitro and in vivo research results associated with the neuroprotective action of humanin as well as of various, mainly synthetic, analogues of the peptide; moreover, the main mode(s)/mechanism(s) through which humanin and humanin analogues may exert in vitro and in vivo regarding neuroprotection have been reported. The prospects of humanin and humanin analogues to be further investigated in the frame of future research endeavors against neurodegenerative/neural diseases have also been briefly discussed.