Neuroprotective effect of dipeptide AVP(4-5)-NH2 is associated with nerve growth factor and heat shock protein HSP70

Linking Heat Shock Protein 70 and Parkin in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disease that affects millions of elderly people worldwide and is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The precise mechanisms underlying the pathogenesis of PD are still not fully understood, but it is well accepted that the misfolding, aggregation, and abnormal degradation of proteins are the key causative factors of PD. Heat shock protein 70 (Hsp70) is a molecular chaperone that participates in the degradation of misfolded and aggregated proteins in living cells and organisms. Parkin, an E3 ubiquitin ligase, participates in the degradation of proteins via the proteasome pathway. Recent studies have indicated that both Hsp70 and Parkin play pivotal roles in PD pathogenesis. In this review, we focus on discussing how dysregulation of Hsp70 and Parkin leads to PD pathogenesis, the interaction between Hsp70 and Parkin in the context of PD and their therapeutic applications in PD.

Vasopressin as a Possible Link between Sleep-Disturbances and Memory Problems

Normal biological rhythms, including sleep, are very important for a healthy life and their disturbance may induce-among other issues-memory impairment, which is a key problem of many psychiatric pathologies. The major brain center of circadian regulation is the suprachiasmatic nucleus, and vasopressin (AVP), which is one of its main neurotransmitters, also plays a key role in memory formation. In this review paper, we aimed to summarize our knowledge on the vasopressinergic connection between sleep and memory with the help of the AVP-deficient Brattleboro rat strain. These animals have EEG disturbances with reduced sleep and impaired memory-boosting theta oscillation and show memory impairment in parallel. Based upon human and animal data measuring AVP levels, haplotypes, and the administration of AVP or its agonist or antagonist via different routes (subcutaneous, intraperitoneal, intracerebroventricular, or intranasal), V1a receptors (especially of hippocampal origin) were implicated in the sleep-memory interaction. All in all, the presented data confirm the possible connective role of AVP between biological rhythms and memory formation, thus, supporting the importance of AVP in several psychopathological conditions.

Lung-brain axis: Metabolomics and pathological changes in lungs and brain of respiratory syncytial virus-infected mice

The lung-brain axis is an emerging area of study that got its basis from the gut-brain axis biological pathway. Using Respiratory Synctial Virus (RSV) as the model of respiratory viral pathogen, this study aims to establish some biological pathways. After establishing the mice model, the inflammation in lung and brain were assayed using Hematoxylin-eosin staining, indirect immunofluorescence (IFA), and quantitative reverse-transcription polymerase chain reaction. The biological pathways between lung and brain were detected through metabolomics analysis. In lung, RSV infection promoted epithelial shedding and infiltration of inflammatory cells. Also, RSV immunofluorescence and titerss were significantly increased. Moreover, interleukin (IL)-1, IL-6 and tumor necrosis factor-α (TNF-α) were also significantly increased after RSV infection. In brain, the cell structure of hippocampal CA1 area was loose and disordered. Inflammatory cytokines IL-6 and IL-1β expression in the brain also increased, however, TNF-α expression showed no differences among the control and RSV group. We observed an increased expression of microglia biomarker IBA-1 and decreased neuronal biomarker NeuN. In addition, RSV mRNA expression levels were also increased in the brains. 15 metabolites were found upregulated in the RSV group including nerve-injuring metabolite glutaric acid, hydroxyglutaric acid and Spermine. ɑ-Estradiol increased significantly while normorphine decreased significantly at Day 7 of infection among the RSV group. This study established a mouse model for exploring the pathological changes in lungs and brains. There are many biological pathways between lung and brain, including direct translocation of RSV and metabolite pathway.

In Silico design of AVP (4-5) peptide and synthesis, characterization and in vitro activity of chitosan nanoparticles

BACKGROUND

Arginine-vasopressin (AVP) is a neuropeptide and provides learning and memory modulation. The AVP (4-5) dipeptide corresponds to the N-terminal fragment of the major vasopressin metabolite AVP (4-9), has a neuroprotective effect and used in the treatment of Alzheimer's and Parkinson's disease.

METHODS

The main objective of the present study is to evaluate the molecular mechanism of AVP (4-5) dipeptide and to develop and synthesize chitosan nanoparticle formulation using modified version of ionic gelation method, to increase drug effectiveness. For peptide loaded chitosan nanoparticles, the synthesized experiment medium was simulated for the first time by molecular dynamics method and used to determine the stability of the peptide, and the binding mechanism to protein (HSP70) was also investigated by molecular docking calculations. A potential pharmacologically features of the peptide was also characterized by ADME (Absorption, Distribution, Metabolism and Excretion) analysis. The characterization, in vitro release study, encapsulation efficiency and loading capacity of the peptide loaded chitosan nanoparticles (CS NPs) were performed by Dynamic Light Scattering (DLS), UV-vis absorption (UV), Scanning Electron Microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy techniques. Additionally, in vitro cytotoxicity of the peptide on human neuroblastoma cells (SH-SY5Y) was examined with XTT assay and the statistical analysis was evaluated.

RESULTS

The results showed that; hydrodynamic size, zeta potential and polydispersity index (PdI) of the peptide-loaded CS NPs were 167.6 nm, +13.2 mV, and 0.211, respectively. In vitro release study of the peptide-loaded CS NPs showed that 17.23% of the AVP (4-5)-NH2 peptide was released in the first day, while 61.13% of AVP (4-5)-NH2 peptide was released in the end of the 10th day. The encapsulation efficiency and loading capacity were 99% and 10%, respectively. According to the obtained results from XTT assay, toxicity on SHSY-5Y cells in the concentration from 0.01 μg/μL to 30 μg/μL were evaluated and no toxicity was observed. Also, neuroprotective effect was showed against H₂O₂ treatment.

CONCLUSION

The experimental medium of peptide-loaded chitosan nanoparticles was created for the first time with in silico system and the stability of the peptide in this medium was carried out by molecular dynamics studies. The binding sites of the peptide with the HSP70 protein were determined by molecular docking analysis. The size and morphology of the prepared NPs capable of crossing the blood-brain barrier (BBB) were monitored using DLS and SEM analyses, and the encapsulation efficiency and loading capacity were successfully performed with UV Analysis. In vitro release studies and in vitro cytotoxicity analysis on SHSY-5Y cell lines of the peptide were conducted for the first time. Grapical abstract.

Novel Technologies for Dipeptide Drugs Design and their Implantation

The article is an overview of author's data obtained in the framework of the project "The Creation of dipeptide preparations" at the V.V. Zakusov Institute of Pharmacology, Moscow, Russia. Advantages of dipeptides over longer peptides consist in that they are orally active owing to higher stability and ability to penetrate biological barriers due to the presence of specific ATP-dependent transporters in enterocytes and blood-brain barrier. Two original approaches for dipeptide drugs design have been developed. Both of them are based on the idea of a leading role of central dipeptide fragment of the peptide chain beta-turn in the peptide-receptor interaction. The first approach, named "peptide drug-based design" represents the transformation of known nonpeptide drug into its dipeptide topological analog. The latter usually corresponds to a beta-turn of some regulatory peptide. The second approach represents the design of tripeptoide mimetic of the beta-turn of regulatory peptide or protein. The results of the studies, which led to the discovery of endogenous prototypes of the known non-peptide drugs piracetam and sulpiride, are presented herein. The paper discusses the process, based on the abovementioned principles, that was used in designing of nontoxic, orally available, highly effective dipeptide drugs: nootropic noopept, dipeptide analog of piracetam; antipsychotic dilept, neurotensin tripeptoid analog; selective anxiolytic GB-115, tripeptoid analog of CCK-4, and potential neuroprotector GK-2, homodimeric dipeptide analog of NGF.