Glutaminyl cyclase inhibitor exhibits anti-inflammatory effects in both AD and LPS-induced inflammatory model mice

Identification of imidazole-based small molecules to combat cognitive disability caused by Alzheimer's disease: A molecular docking and MD simulations based approach

Alzheimer's disease (AD) is a chronic neurodegenerative disorder that is the primary cause of dementia. It is characterised by the gradual loss of brain cells, which results in memory loss and cognitive dysfunction. One of the hallmarks of AD is an abnormally upregulated glutaminyl-peptide cyclotransferase (QPCT or QC) enzyme. Not only AD, but QC has also been implicated with pathological conditions like Huntington's disease (HD), melanomas, carcinomas, atherosclerosis, and septic arthritis. Therefore, the inhibition of QC emerged as a potential strategy for preventing multiple pathological conditions. Considering this, we screened a library of 153,536 imidazole-based compounds against a doubly mutant (Y115E-Y117E) QC target. Molecular docking based virtual screening and absorption, distribution, metabolism, excretion/toxicity (ADME/T) predictions identified five compounds, namely 118981836, 136459842, 139388116, 139388226, and 139958725. Furthermore, molecular dynamics (MD) simulations of 500 ns were conducted to investigate the behaviour of the identified compounds with the target receptor. The results were compared to the co-ligand by analysing RMSD, RMSF, and SASA parameters. To our knowledge, this is the first computational study that employed a protein with double mutation to identify new imidazole-based QC-inhibitors.

X-ray Structure-Guided Discovery of a Potent Benzimidazole Glutaminyl Cyclase Inhibitor That Shows Activity in a Parkinson's Disease Mouse Model

The secretory glutaminyl cyclase (sQC) and Golgi-resident glutaminyl cyclase (gQC) are responsible for N-terminal protein pyroglutamation and associated with various human diseases. Although several sQC/gQC inhibitors have been reported, only one inhibitor, PQ912, is currently undergoing clinic trials for the treatment of Alzheimer's disease. We report an X-ray crystal structure of sQC complexed with PQ912, revealing that the benzimidazole makes "anchor" interactions with the active site zinc ion and catalytic triad. Structure-guided design and optimization led to a series of new benzimidazole derivatives exhibiting nanomolar inhibition for both sQC and gQC. In a MPTP-induced Parkinson's disease (PD) mouse model, BI-43 manifested efficacy in mitigating locomotor deficits through reversing dopaminergic neuronal loss, reducing microglia, and decreasing levels of the sQC/gQC substrates, α-synuclein, and CCL2. This study not only offers structural basis and new leads for drug discovery targeting sQC/gQC but also provides evidence supporting sQC/gQC as potential targets for PD treatment.

Development of lactoferrin-coated multifunctional copolymer micelles to cross the blood-brain barrier

The blood-brain barrier (BBB) prevents pathogens and toxins in the bloodstream from reaching the brain, but also inhibits the delivery of agents intended to treat central nervous system disorders, such as Alzheimer's disease (AD). In this study, we prepared and evaluated a novel nano-delivery vehicle system composed of lactoferrin-conjugated (Lf-PIC@Se) micelles. We used a COOH-PEG-PAsp-PV@Se synthesis-based method to prepare the micelles, which involved self-assembly followed by EDC-NHS coupling. Using glutaminyl cyclase inhibitor 8 as a model encapsulated chemical, Lf-PIC@Se micelles achieved a good loading capacity. In vitro analysis demonstrated that Lf-PIC@Se/8 micelles were stable in both neutral and acidic pH solutions in the presence or absence of H2O2, and confirmed their biosafety and compatibility in PC12 and bEND.3 cells. Notably, the cell uptake of Lf-PIC@Se/C6 micelles was much higher than that of PIC@Se micelles, and occurred through LfR-mediated endocytosis. The presence of Se meant that Lf-PIC@Se micelles acted as ROS scavengers in PC12 cells under H2O2-induced oxidative stress, which inhibited oxidative damage and increased mitochondrial membrane potential. Hemolysis assays further demonstrated that Lf-PIC@Se represent a biocompatible carrier. Finally, in vivo experiments in mice suggested that Lf-PIC@Se micelles successfully crossed the BBB, confirming their potential as vehicles for drug delivery when treating AD and other central nervous system disorders.

Discovery of potential scaffolds for glutaminyl cyclase inhibitors: Virtual screening, synthesis, and evaluation

Glutaminyl cyclase (QC) plays a crucial role in the early stages of Alzheimer's disease (AD), thus inhibition of QC may be a promising strategy for the treatment of early AD. Therefore, QC inhibitors with novel chemical scaffolds may contribute to the development of additional anti-AD agents. We conducted a virtual screening of 3 million compounds from the Chemdiv and Enamine databases, to discover potential scaffolds for QC inhibitors. Three scaffolds, 120974, 147706, and 141449, were selected from this structure-based virtual screening through a combination of pharmacophore modeling, a receptor-ligand pharmacophore model, and the GALAHAD model, and furtherly filtered by chelation with zinc ion and docking properties. Consequently, three compounds, 1, 2, and 3, were designed and synthesized based on these three scaffolds, respectively. The IC50 of compounds 1 and 3 against QC were 14.19 ± 4.21 and 4.34 ± 0.35 μM, respectively. Our results indicate that the new scaffolds selected using a virtual screening process exhibit potential as novel QC inhibitors.

Therapeutic potential of glutaminyl cyclases: Current status and emerging trends

Glutaminyl cyclase (QC) activity has been identified as a key effector in distinct biological processes. Human glutaminyl-peptide cyclotransferase (QPCT) and glutaminyl-peptide cyclotransferase-like (QPCTL) are considered attractive therapeutic targets in many human disorders, such as neurodegenerative diseases, and a range of inflammatory conditions, as well as for cancer immunotherapy, because of their capacity to modulate cancer immune checkpoint proteins. In this review, we explore the biological functions and structures of QPCT/L enzymes and highlight their therapeutic relevance. We also summarize recent developments in the discovery of small-molecule inhibitors targeting these enzymes, including an overview of preclinical and clinical studies.

Human umbilical cord-derived mesenchymal stem cells promote repair of neonatal brain injury caused by hypoxia/ischemia in rats

Administration of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) is believed to be an effective method for treating neurodevelopmental disorders. In this study, we investigated the possibility of hUC-MSCs treatment of neonatal hypoxic/ischemic brain injury associated with maternal immune activation and the underlying mechanism. We established neonatal rat models of hypoxic/ischemic brain injury by exposing pregnant rats to lipopolysaccharide on day 16 or 17 of pregnancy. Rat offspring were intranasally administered hUC-MSCs on postnatal day 14. We found that polypyrimidine tract-binding protein-1 (PTBP-1) participated in the regulation of lipopolysaccharide-induced maternal immune activation, which led to neonatal hypoxic/ischemic brain injury. Intranasal delivery of hUC-MSCs inhibited PTBP-1 expression, alleviated neonatal brain injury-related inflammation, and regulated the number and function of glial fibrillary acidic protein-positive astrocytes, thereby promoting plastic regeneration of neurons and improving brain function. These findings suggest that hUC-MSCs can effectively promote the repair of neonatal hypoxic/ischemic brain injury related to maternal immune activation through inhibition of PTBP-1 expression and astrocyte activation.

Molecular mechanisms in Alzheimer's disease and related potential treatments such as structural target convergence of antibodies and simple organic molecules

The amyloid cascade is the most frequently accepted hypothesis of Alzheimer's Disease (AD). According to this hypothesis, the formation of plaques precedes the appearance of fibrillary tangles. Therapeutic agents able to inhibit the formation of plaques are therefore considered as potential disease-modifying treatments (DMT) that could prevent or limit the progression of AD. Plaques are deposits formed by aggregates of amyloid-β (Aβ)-peptides. These peptides are metabolites of amyloid precursor protein (APP) first mediated by two enzymes: β-secretase 1 (BACE1) and γ-secretase. Molecular identification of these two enzymes has stimulated the development of their inhibitors. The clinical testing of these two classes of molecules has not been successful to date. The oligomerization of Aβ-peptides into plaques is now targeted by immunological approaches such as antibodies and vaccines. Structural consideration of the Aβ-peptide sequence led to the launch of the antibody Aducanumab. Several other antibodies are in late clinical phases. Progress in the understanding of the effects of N-truncated Aβ-peptides such as pE3-42, formed by the action of recently well characterized enzymes (aminopeptidase A, dipeptidylpeptidase-4 and glutaminyl cyclase) suggests that oligomerization can be limited either by enzyme inhibitors or antibody approaches. This strategy associating two structurally interconnected mechanisms is focused in this review.

Non-Coding RNAs as Novel Regulators of Neuroinflammation in Alzheimer's Disease

Alzheimer’s disease (AD) is one of the most common causes of dementia. Although significant breakthroughs have been made in understanding the progression and pathogenesis of AD, it remains a worldwide problem and a significant public health burden. Thus, more efficient diagnostic and therapeutic strategies are urgently required. The latest research studies have revealed that neuroinflammation is crucial in the pathogenesis of AD. Non-coding RNAs (ncRNAs), including long noncoding RNAs (lncRNAs), microRNAs (miRNAs), circular RNAs (circRNAs), PIWI-interacting RNAs (piRNAs), and transfer RNA-derived small RNAs (tsRNAs), have been strongly associated with AD-induced neuroinflammation. Furthermore, several ongoing pre-clinical studies are currently investigating ncRNA as disease biomarkers and therapeutic interventions to provide new perspectives for AD diagnosis and treatment. In this review, the role of different types of ncRNAs in neuroinflammation during AD are summarized in order to improve our understanding of AD etiology and aid in the translation of basic research into clinical practice.

In vitro Neuroprotective Potential and Lipidomics Study of Olive Leaves Extracts Enriched in Triterpenoids

Alzheimer's Disease (AD) is the most common form of dementia that is associated with extracellular amyloid beta (Aβ) plaque formation. Genetic, environmental, and nutrition factors have been suggested as contributors to oxidative stress and neuroinflammation events that are connected to AD etiology, and secondary metabolites, such as triterpenes, have shown promising results in AD prevention. In this work, the neuroprotective and anti-inflammatory potential of an olive leaves fraction enriched in triterpenoid compounds obtained using supercritical fluid extraction (SFE) and dynamic adsorption/desorption using sea sand as adsorbent has been performed. In addition, a comprehensive lipidomics study of the response of SH-SY5Y neuroblastoma cell line to this fraction was carried out using advanced analytical methodologies, namely, charged-surface hybrid chromatography-quadrupole-time of flight mass spectrometry (CSH-Q-TOF MS/MS). The use of freely available lipidomic annotation tools and databases, and stringent cut-off filters allowed the annotation of more than 250 intracellular lipids. Advanced bioinformatics and statistical tools showed a number of phosphatidylcholines and phosphatidylethanolamines significantly increased, which could explain the protection against the cell death caused by Aβ1-42. Moreover, several triacylglycerols were found decreased. These results suggest triterpenoids from olive leaves as good neuroprotective candidates, and open a new gate for future experiments using in vivo models to corroborate this hypothesis.

A patent review of glutaminyl cyclase inhibitors (2004-present)

Introduction: Glutaminyl cyclase (QC) enzymes catalyze the post-translational processing of several substrates with N-terminal glutamine or glutamate to form pyroglutamate (pE) residue. In addition to physiological functions, emerging evidence demonstrates that human QCs play a part in pathological processes in diverse diseases such as Alzheimer's disease (AD), inflammatory and cancer diseases.Areas covered: In recent years, efforts to effectively develop QC small-molecule inhibitors have been made and different chemical classes have been disclosed. This review summarizes the patents/applications regarding QC inhibitors released from 2004 (first patent) to now. The patents are mostly described in terms of chemical structures, biochemical/pharmacological activities, and potential clinical applications.Expert opinion: For more than 15 years of research, the knowledge on the QC activity domain has considerably increased and therapeutic potential of QC inhibitors has been explored. An important number of studies and patents have been published to expand the use of QC inhibitors. QC enzymes are pharmacologically interesting targets to be used as an AD-modifying therapy, or for other QC-associated disorder. Distinct classes of chemical scaffolds and potential clinical uses have been claimed by various organizations. For the coming years, there is much to experience in the QC field.

Pharmaceuticals agents for preventing NSAID-induced gastric ulcers: a patent review

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a class of drugs widely used due to their pharmacological potential, demonstrating anti-inflammatory, analgesic, or antipyretic activity. However, prolonged use of these medications can lead to the development of gastric ulcers in patients. This review aimed to find patents for drugs with an anti-inflammatory and gastroprotective character to treat NSAID-induced gastric ulcers.

AREAS COVERED

For the treatment of NSAID-induced gastric ulcers, formulations with different action mechanisms were found, including donors of nitric oxide, heterocyclic compounds, and natural products.

EXPERT OPINION

Many of the structures found have already been used in clinic settings and others, and according to the results found, they are promising for the treatment of gastric ulcers.

Increased glutaminyl cyclase activity in brains of Alzheimer's disease individuals

Glutaminyl cyclases (QC) catalyze the formation of neurotoxic pGlu-modified amyloid-β peptides found in the brains of people with Alzheimer's disease (AD). Reports of several-fold increases in soluble QC (sQC) expression in the brain and peripheral circulation of AD individuals has prompted the development of QC inhibitors as potential AD therapeutics. There is, however, a lack of standardized quantitative data on QC expression in human tissues, precluding inter-laboratory comparison and validation. We tested the hypothesis that QC is elevated in AD tissues by quantifying levels of sQC protein and activity in post-mortem brain tissues from AD and age-matched control individuals. We found a modest but statistically significant increase in sQC protein, which paralleled a similar increase in enzyme activity. In plasma samples sourced from the Australian Imaging, Biomarker and Lifestyle study we determined that QC activity was not different between the AD and control group, though a modest increase was observed in female AD individuals compared to controls. Plasma QC activity was further correlated with levels of circulating monocytes in AD individuals. These data provide quantitative evidence that alterations in QC expression are associated with AD pathology.