Dietary Natural Flavonoids: Intervention for MAO-B Against Parkinson's Disease.

Parkinson's disease (PD) stands as the second most common neurological disorder after Alzheimer's disease, primarily affecting the elderly population and significantly compromising their quality of life. The precise etiology of PD remains elusive, but recent research has shed light on potential factors, including the formation of α-synuclein aggregates, oxidative stress, neurotransmitter imbalances, and dopaminergic neurodegeneration in the substantia nigra pars compacta (SNpc) region of the brain, culminating in motor symptoms such as bradykinesia, akinesia, tremors, and rigidity. Monoamine oxidase (MAO) is an essential enzyme, comprising two isoforms, MAO-A and MAO-B, responsible for the oxidation of monoamines such as dopamine. Increased MAO-B activity is responsible for decreased dopamine levels in the SNpc region of mid brain which is remarkably associated with the pathogenesis of PD-like manifestations. Inhibitors of MAO-B enhance striatal neuronal responses to dopamine, making them valuable in treating PD, which involves dopamine deficiency. Clinically approved MAO-B inhibitors such as selegiline, L-deprenyl, pargyline, and rasagiline are employed in the management of neurodegenerative conditions associated with PD. Current therapeutic interventions including MAO-B inhibitors for PD predominantly aim to alleviate these motor symptoms but often come with a host of side effects that can be particularly challenging for the patients. While effective, they have limitations, prompting a search for alternative treatments, there is a growing interest in exploring natural products notably flavonoids as potential sources of novel MAO-B inhibitors. In line with that, the present review focuses on natural flavonoids of plant origin that hold promise as potential candidates for the development of novel MAO-B inhibitors. The discussion encompasses both in vitro and in vivo studies, shedding light on their potential therapeutic applications. Furthermore, this review underscores the significance of exploring natural products as valuable reservoirs of MAO-B inhibitors, offering new avenues for drug development and addressing the pressing need for improved treatments in PD-like pathological conditions. The authors of this review majorly explore the neuroprotective potential of natural flavonoids exhibiting notable MAO-B inhibitory activity and additionally multi-targeted approaches in the treatment of PD with clinical evidence and challenges faced in current therapeutic approaches.

Transcriptome and Metabolome Analyses of Aroma Differences between Chardonnay and a Chardonnay Bud Sport.

Chardonnay is one of the most popular white grape wine varieties in the world, but this wine lacks typical aroma, considered a sensory defect. Our research group identified a Chardonnay bud sport with typical muscat characteristics. The goal of this work was to discover the key candidate genes related to muscat characteristics in this Chardonnay bud sport to reveal the mechanism of muscat formation and guide molecular design breeding. To this end, HS-SPME-GC-MS and RNA-Seq were used to analyze volatile organic compounds and the differentially expressed genes in Chardonnay and its aromatic bud sport. Forty-nine volatiles were identified as potential biomarkers, which included mainly aldehydes and terpenes. Geraniol, linalool, and phenylacetaldehyde were identified as the main aroma components of the mutant. The GO, KEGG, GSEA, and correlation analysis revealed HMGR, TPS1, TPS2, TPS5, novel.939, and CYP450 as key genes for terpene synthesis. MAO1 and MAO2 were significantly downregulated, but there was an increased content of phenylacetaldehyde. These key candidate genes provide a reference for the development of functional markers for muscat varieties and also provide insight into the formation mechanism of muscat aroma.

Chemical complementarity of tumor resident, T-cell receptor CDR3s and renalase-1 correlates with increased melanoma survival.

Overexpression of the secretory protein renalase-1 negatively impacts the survival of melanoma and pancreatic cancer patients, while inhibition of renalase-1 signaling drives tumor rejection by promoting T-cell activation. Thus, we investigated the chemical complementarity between melanoma-resident, T-cell receptor (TCR) complementarity-determining region 3 (CDR3) amino acid sequences (AAs) and the renalase-1 protein. Increasing complementarity of TCR CDR3s to renalase-1 AAs, as assessed by a chemical complementarity scoring algorithm, was associated with improved overall survival (OS) in melanoma patients. The expression levels of several immune signature genes were significantly, positively correlated with increasing TCR CDR3-renalase-1 complementarity scores. Additionally, the survival association observed with high complementarity of TCR CDR3s to renalase-1 AAs was more robust in cases with low renalase-1 gene expression levels. Mapping of TCR CDR3-renalase-1 in silico interaction sites identified major epitope candidates including RP220, the signaling module of the renalase-1 protein, consistent with the fact that a monoclonal antibody to RP220 is a potent inhibitor of melanoma growth. These findings indicate that renalase-1 is a potential antigen for TCR recognition in melanoma and could be considered as a target for immunotherapy.

Monoamine oxidases activity maintains endometrial monoamine homeostasis and participates in embryo implantation and development.

BACKGROUND: Monoamine oxidases (MAOs) is an enzyme that catalyzes the deamination of monoamines. The current research on this enzyme is focused on its role in neuropsychiatric, neurodevelopmental, and neurodegenerative diseases. Indeed, MAOs with two isoforms, namely, A and B, are located on the outer mitochondrial membrane and are widely distributed in the central nervous system and peripheral tissues. Several reports have described periodic changes in the levels of this enzyme in the human endometrial tissue. RESULTS: The novel role of MAOs in endometrial receptivity establishment and embryonic development by maintaining monoamine homeostasis was investigated in this study. MAOs activity was observed to be enhanced during the first trimester in both humans and mice under normal conditions. However, under pathological conditions, MAOs activity was reduced and was linked to early pregnancy failure. During the secretory phase, the endometrial stromal cells differentiated into decidual cells with a stronger metabolism of monoamines by MAOs. Excessive monoamine levels cause monoamine imbalance in decidual cells, which results in the activation of the AKT signal, decreased FOXO1 expression, and decidual dysfunction. CONCLUSIONS: The findings suggest that endometrial receptivity depends on the maintenance of monoamine homeostasis via MAOs activity and that this enzyme participates in embryo implantation and development.

Association of monoaminergic gene polymorphisms in chronic inflammatory pulmonary disease patients with successful smoking cessation.

BACKGROUND: Albeit smoking cessation has unequivocal health benefits, attempts to quit are not unanimous, even in patient populations at high risk for smoking-related diseases cessation. Allelic variations of enzymes involved in dopamine metabolism are being considered as candidates for nicotine addiction. We set out to assess whether rs4680 G/A and rs2235186 G/A polymorphisms of COMT and MAO-A, respectively are associated with the ability to quit smoking in chronic inflammatory pulmonary disease patients. METHODS: Patients managed for chronic inflammatory pulmonary disease by the Department of Pulmonology (University of Debrecen, Hungary), with a current or past smoking habit were included in the current analysis. The study was designed in line with the STROBE statement for cross-sectional studies and was approved by the National Center for Public Health, Hungary. Genomic DNA was extracted from peripheral blood specimens. SNPs were genotyped using TaqMan SNP genotyping assays. RESULTS: rs4680 COMT polymorphism showed significant effect for successful smoking cessation in patients with pulmonary disease. Accordingly, A/A subjects had lower odds for successful smoking cessation (odds ratio 0.37; 95% confidence interval 0.20-0.69, p = 0.002 (additive model). On the other hand, patients homozygous for the minor allele (A) at rs2235186 of MAO-A showed a non-significant trend toward increased odds for successful smoking cessation. CONCLUSIONS: The presence of the minor allele for rs4680 COMT was shown to decrease the odds for successful smoking cessation, a finding that may be interpreted in view of the altered balance between tonic and phasic dopamine release.

Exposure to thimerosal induces behavioral abnormality in the early life stages of zebrafish via altering amino acid homeostasis.

Thimerosal (THI) has become a significant source of organic mercury pollutants in aquatic ecosystems, but there is limited information regarding its adverse effects on fish. In this study, zebrafish embryos were exposed to THI at 0 (control), 5.0, and 50 ng/L from 0-5 days post fertilization (dpf), and variations in their survival, development, behavior, free amino acid contents, and the biochemical responses involved in monoaminergic systems were examined. Although THI exposure did not significantly affect the survival, heart rate, or hatching time of zebrafish embryos, it substantially increased swimming velocity (136-154 % of the control) and reduced exploratory behavior (141-142 % of the control) in zebrafish larvae at 5 dpf. Exposure also significantly altered the amino acid contents (51-209 % of the control) and monoamine levels (70-154 % of the control) in zebrafish larvae, some of which displayed significant correlations with behavioral traits. THI significantly elevated dopamine receptor gene expression and monoamine oxidase activity in zebrafish larvae. Adding extra phenylalanine or tryptophan to the E3 medium facilitates the recovery of zebrafish larvae from the abnormal behaviors induced by THI. These findings reveal for the first time that THI exposure at the level of ng/L is sufficient to induce neurobehavioral toxic effects in the early life stages of zebrafish, and disrupting amino acid homeostasis is a critical underlying mechanism. This study provides valuable insights into the toxicity of THI to fish and highlights the importance of assessing its potential risks to aquatic ecosystems.

Neural acetylcholinesterase and monoamine oxidase deregulation during streptozotocin-induced behavioral, metabolic and redox modification in Nauphoeta cinerea.

Genetic and environmental factors have been linked with neurodegeneration, especially in the elderly. Yet, efforts to impede neurodegenerative processes have at best addressed symptoms instead of underlying pathologies. The gap in the understanding of neuro-behavioral plasticity is consistent from insects to mammals, and cockroaches have been proven to be effective models for studying the toxicity mechanisms of various chemicals. We therefore used head injection of 74 and 740 nmol STZ in Nauphoeta cinerea to elucidate the mechanisms of chemical-induced neurotoxicity, as STZ is known to cross the blood-brain barrier. Neurolocomotor assessment was carried out in a new environment, while head homogenate was used to estimate metabolic, neurotransmitter and redox activities, followed by RT-qPCR validation of relevant cellular signaling. STZ treatment reduced the distance and maximum speed travelled by cockroaches, and increased glucose levels while reducing triglyceride levels in neural tissues. The activity of neurotransmitter regulators - AChE and MAO was exacerbated, with concurrent upregulation of glucose sensing and signaling, and increased mRNA levels of redox regulators and inflammation-related genes. Consequently, STZ neurotoxicity is conserved in insects, with possible implications for using N. cinerea to target the multi-faceted mechanisms of neurodegeneration and test potential anti-neurodegenerative agents.

Antiparkinson potential of khellin on rotenone-induced Parkinson's disease in a zebrafish model: targeting MAO, inflammatory, and oxidative stress markers with molecular docking, MD simulations, and histopathology evidence.

In this study, the antiparkinson effect of khellin (KL) on rotenone-induced Parkinson's disease (PD) was examined in zebrafish. Initially, In silico evaluations, such as drug likeness and ADME/T analysis, confirmed the pharmacological viability of KL. Molecular docking and molecular dynamics (MD) analysis revealed stable binding interactions between KL and monamine oxidase B (MAO-B). Molecular docking results for KL and pioglitazone (CCl) revealed binding energies of -6.5 and -10.4 kcal/mol, respectively. Later, molecular dynamics (MD) studies were performed to assess the stability of these complexes, which yielded binding energies of -36.04 ± 55.21 and -56.2 ± 80.63 kJ/mol for KL and CCl, respectively. These results suggest that KL exhibits considerable binding affinity for MAO-B. In In vitro studies, according to the DPPH free radical scavenging assay, KL exhibited significant antioxidant effects, indicating that it can promote redox balance with an IC50 value of 22.68 ± 0.5 µg/ml. In vivo studies and evaluation of locomotor activity, social interaction, histopathology and biochemical parameters were conducted in KL-treated zebrafish to measure SOD and GSH antioxidant activity, the oxidative stress marker malondialdehyde (MDA), the inflammatory marker myeloperoxidase (MPO) and MAO-B. However, while the locomotor and social interaction abilities of the rotenone-treated zebrafish were significantly reduced, KL treatment significantly improved locomotor activity (p < 0.001) and social interaction (p < 0.001). KL alleviated PD symptoms, as indicated by significant increases in SOD (p < 0.01), GSH (p < 0.001), MDA (p < 0.001), MAO-B (p < 0.001) and MPO (p < 0.001) in rotenone-induced PD fish (p<0.001) significantly reduced activities. Histopathological studies revealed that rotenone-induced brain hyperintensity and abnormal cellularity of the periventricular gray matter in the optic tectum were significantly reduced by KL treatment. This study provides a strong basis for developing KL as a new candidate for the treatment of Parkinson's disease, with the prospect of improved safety profiles and efficacy.

Monoamine oxidase and neurodegeneration: Mechanisms, inhibitors and natural compounds for therapeutic intervention.

Mammalian flavoenzyme Monoamine oxidase (MAO) resides on the outer mitochondrial membrane (OMM) and it is involved in the metabolism of different monoamine neurotransmitters in brain. During MAO mediated oxidative deamination of relevant substrates, H2O2 is released as a catalytic by-product, thus serving as a major source of reactive oxygen species (ROS). Under normal conditions, MAO mediated ROS is reported to propel the functioning of mitochondrial electron transport chain and phasic dopamine release. However, due to its localization onto mitochondria, sudden elevation in its enzymatic activity could directly impact the form and function of the organelle. For instance, in the case of Parkinson's disease (PD) patients who are on l-dopa therapy, the enzyme could be a concurrent source of extensive ROS production in the presence of uncontrolled substrate (dopamine) availability, thus further impacting the health of surviving neurons. It is worth mentioning that the expression of the enzyme in different brain compartments increases with age. Moreover, the involvement of MAO in the progression of neurological disorders such as PD, Alzheimer's disease and depression has been extensively studied in recent times. Although the usage of available synthetic MAO inhibitors has been instrumental in managing these conditions, the associated complications have raised significant concerns lately. Natural products have served as a major source of lead molecules in modern-day drug discovery; however, there is still no FDA-approved MAO inhibitor which is derived from natural sources. In this review, we have provided a comprehensive overview of MAO and how the enzyme system is involved in the pathogenesis of different age-associated neuropathologic conditions. We further discussed the applications and drawbacks of the long-term usage of presently available synthetic MAO inhibitors. Additionally, we have highlighted the prospect and worth of natural product derived molecules in addressing MAO associated complications.

Neurobehavioral, neurotransmitter and redox modifications in Nauphoeta cinerea under mixed heavy metal (silver and mercury) exposure.

Heavy metals are encountered in nature, and are used in several human endeavors, including in dental fillings. It is well known that the safety of metals depends on their chemical form, as well as the dose and route through which biological systems are exposed to them. Here, we used the Nauphoeta cinerea model to examine the mechanism by which salts of the heavy metals used in dental fillings - silver and mercury - exert their neurotoxicity. Nymphs exposed to heavy metals presented with reduced motor and exploratory abilities as they spent more time immobile, especially in the periphery of a novel object, and covered less distance compared with control nymphs. Exposure to AgNO3 and HgCl2 also exacerbated levels of oxidative stress markers (MDA & ROS) and the neurotransmitter regulators - AChE and MAO, while reducing antioxidant activity markers, both in biochemical (thiol & GST) and RT-qPCR (TRX, GST, SOD, Catalase) examinations, in neural tissues of the cockroach. The observed disruptions in neurolocomotor control, synaptic transmission and redox balance explain how heavy metal salts may predispose organisms to neurological disorders.

A study predicting long-term survival capacity in postoperative advanced gastric cancer patients based on MAOA and subcutaneous muscle fat characteristics.

BACKGROUND: The prognosis of advanced gastric cancer (AGC) is relatively poor, and long-term survival depends on timely intervention. Currently, predicting survival rates remains a hot topic. The application of radiomics and immunohistochemistry-related techniques in cancer research is increasingly widespread. However, their integration for predicting long-term survival in AGC patients has not been fully explored. METHODS: We Collected 150 patients diagnosed with AGC at the Affiliated Zhongshan Hospital of Dalian University who underwent radical surgery between 2015 and 2019. Following strict inclusion and exclusion criteria, 90 patients were included in the analysis. We Collected postoperative pathological specimens from enrolled patients, analyzed the expression levels of MAOA using immunohistochemical techniques, and quantified these levels as the MAOAHScore. Obtained plain abdominal CT images from patients, delineated the region of interest at the L3 vertebral body level, and extracted radiomics features. Lasso Cox regression was used to select significant features to establish a radionics risk score, convert it into a categorical variable named risk, and use Cox regression to identify independent predictive factors for constructing a clinical prediction model. ROC, DCA, and calibration curves validated the model's performance. RESULTS: The enrolled patients had an average age of 65.71 years, including 70 males and 20 females. Multivariate Cox regression analysis revealed that risk (P = 0.001, HR = 3.303), MAOAHScore (P = 0.043, HR = 2.055), and TNM stage (P = 0.047, HR = 2.273) emerged as independent prognostic risk factors for 3-year overall survival (OS) and The Similar results were found in the analysis of 3-year disease-specific survival (DSS). The nomogram developed could predict 3-year OS and DSS rates, with areas under the ROC curve (AUCs) of 0.81 and 0.797, respectively. Joint calibration and decision curve analyses (DCA) confirmed the nomogram's good predictive performance and clinical utility. CONCLUSION: Integrating immunohistochemistry and muscle fat features provides a more accurate prediction of long-term survival in gastric cancer patients. This study offers new perspectives and methods for a deeper understanding of survival prediction in AGC.

Beta cells deficient for Renalase counteract autoimmunity by shaping natural killer cell activity.

Type 1 diabetes (T1D) arises from autoimmune-mediated destruction of insulin-producing pancreatic beta cells. Recent advancements in the technology of generating pancreatic beta cells from human pluripotent stem cells (SC-beta cells) have facilitated the exploration of cell replacement therapies for treating T1D. However, the persistent threat of autoimmunity poses a significant challenge to the survival of transplanted SC-beta cells. Genetic engineering is a promising approach to enhance immune resistance of beta cells as we previously showed by inactivating the Renalase (Rnls) gene. Here, we demonstrate that Rnls loss of function in beta cells shapes autoimmunity by mediating a regulatory natural killer (NK) cell phenotype important for the induction of tolerogenic antigen-presenting cells. Rnls-deficient beta cells mediate cell-cell contact-independent induction of hallmark anti-inflammatory cytokine Tgfß1 in NK cells. In addition, surface expression of regulatory NK immune checkpoints CD47 and Ceacam1 is markedly elevated on beta cells deficient for Rnls. Altered glucose metabolism in Rnls mutant beta cells is involved in the upregulation of CD47 surface expression. These findings are crucial to better understand how genetically engineered beta cells shape autoimmunity, giving valuable insights for future therapeutic advancements to treat and cure T1D.

Chromone-deferiprone hybrids as novel MAO-B inhibitors and iron chelators for the treatment of Alzheimer's disease.

A series of chromone-deferiprone hybrids were designed, synthesized, and evaluated as inhibitors of human monoamine oxidase B (hMAO-B) with iron-chelating activity for the treatment of Alzheimer's disease (AD). The majority exhibited moderate inhibitory activity towards hMAO-B and potent iron-chelating properties. Particularly, compound 25c demonstrated remarkable selectivity against hMAO-B with an IC50 value of 1.58 µM and potent iron-chelating ability (pFe3+ = 18.79) comparable to that of deferiprone (pFe3+ = 17.90). Molecular modeling and kinetic studies showed that 25c functions as a non-competitive hMAO-B inhibitor. According to the predicted results, compound 25c can penetrate the blood-brain barrier (BBB). Additionally, it has been proved to display significant antioxidant activity and the ability to inhibit neuronal ferroptosis. More importantly, compound 25c reduced the cognitive impairment induced by scopolamine and showed significant non-toxicity in short-term toxicity assays. In summary, compound 25c was identified as a potential anti-AD agent with hMAO-B inhibitory, iron-chelating and anti-ferroptosis activities.

Synthesis and biological evaluation of O4'-benzyl-hispidol derivatives and analogs as dual monoamine oxidase-B inhibitors and anti-neuroinflammatory agents.

Design, synthesis, and biological evaluation of two series of O4'-benzyl-hispidol derivatives and the analogous corresponding O3'-benzyl derivatives aiming to develop selective monoamine oxidase-B inhibitors endowed with anti-neuroinflammatory activity is reported herein. The first O4'-benzyl-hispidol derivatives series afforded several more potentially active and MAO-B inhibitors than the O3'-benzyl derivatives series. The most potential compound 2e of O4'-benzyl derivatives elicited sub-micromolar MAO-B IC50 of 0.38 µM with a selectivity index >264 whereas most potential compound 3b of O3'-benzyl derivatives showed only 0.95 MAO-B IC50 and a selectivity index >105. Advancement of the most active compounds showing sub-micromolar activities to further cellular evaluations of viability and induced production of pro-neuroinflammatory mediators confirmed compound 2e as a potential lead compound inhibiting the production of the neuroinflammatory mediator nitric oxide significantly by microglial BV2 cells at 3 µM concentration without significant cytotoxicity up to 30 µM. In silico molecular docking study predicted plausible binding modes with MAO enzymes and provided insights at the molecular level. Overall, this report presents compound 2e as a potential lead compound to develop potential multifunctional compounds.

Effects of gender-affirming hormone therapy on gray matter density, microstructure and monoamine oxidase A levels in transgender subjects.

MAO-A catalyzes the oxidative degradation of monoamines and is thus implicated in sex-specific neuroplastic processes that influence gray matter (GM) density (GMD) and microstructure (GMM). Given the exact monitoring of plasma hormone levels and sex steroid intake, transgender individuals undergoing gender-affirming hormone therapy (GHT) represent a valuable cohort to potentially investigate sex steroid-induced changes of GM and concomitant MAO-A density. Here, we investigated the effects of GHT over a median time period of 4.5 months on GMD and GMM as well as MAO-A distribution volume. To this end, 20 cisgender women, 11 cisgender men, 20 transgender women and 10 transgender men underwent two MRI scans in a longitudinal design. PET scans using [11C]harmine were performed before each MRI session in a subset of 35 individuals. GM changes determined by diffusion weighted imaging (DWI) metrics for GMM and voxel based morphometry (VBM) for GMD were estimated using repeated measures ANOVA. Regions showing significant changes of both GMM and GMD were used for the subsequent analysis of MAO-A density. These involved the fusiform gyrus, rolandic operculum, inferior occipital cortex, middle and anterior cingulum, bilateral insula, cerebellum and the lingual gyrus (post-hoc tests: pFWE+Bonferroni < 0.025). In terms of MAO-A distribution volume, no significant effects were found. Additionally, the sexual desire inventory (SDI) was applied to assess GHT-induced changes in sexual desire, showing an increase of SDI scores among transgender men. Changes in the GMD of the bilateral insula showed a moderate correlation to SDI scores (rho = - 0.62, pBonferroni = 0.047). The present results are indicative of a reliable influence of gender-affirming hormone therapy on 1) GMD and GMM following an interregional pattern and 2) sexual desire specifically among transgender men.

Identification of Sarmentosin as a Key Bioactive from Blackcurrants (Ribes nigrum) for Inhibiting Platelet Monoamine Oxidase in Humans.

Previous clinical studies indicate that monoamine oxidase-B (MAO-B) inhibition by blackcurrants must be predominantly attributed to bioactives other than anthocyanins. In this natural products discovery study, MAO-A/B inhibitory phytochemicals were isolated from blackcurrants, and a double-blind crossover study investigated the efficacy of freeze-dried whole-fruit blackcurrant powder in inhibiting MAO-B compared with blackcurrant juice in healthy adults. Platelet MAO-B inhibition was comparable between powder (89% ± 6) and juice (91% ± 4), and it was positively correlated with MAO-modulated plasma catecholamines, subjective alertness, and reduced mental fatigue, assessed using the Bond-Lader questionnaire. Sarmentosin, a nitrile glycoside, and its hydroxycinnamoyl esters were identified as novel MAO-A/B inhibitors from blackcurrant in vitro, and sarmentosin was demonstrated to inhibit platelet MAO-B activity in vivo. These findings confirm sarmentosin as the primary bioactive for MAO-A/B inhibition in blackcurrants, as well as its bioavailability and stability during freeze-drying, and suggest that consuming blackcurrant powder and juice may positively affect mood in healthy adults.

Renalase peptides reduce pancreatitis severity in mice.

Acute pancreatitis, an acute inflammatory injury of the pancreas, lacks a specific treatment. The circulatory protein renalase is produced by the kidney and other tissues and has potent anti-inflammatory and prosurvival properties. Recombinant renalase can reduce the severity of mild cerulein pancreatitis; the activity is contained in a conserved 20 aa renalase site (RP220). Here, we investigated the therapeutic effects of renalase on pancreatitis using two clinically relevant models of acute pancreatitis. The ability of peptides containing the RP220 site to reduce injury in a 1-day post-endoscopic retrograde cholangiopancreatography (ERCP) and a 2-day severe cerulein induced in mice was examined. The initial dose of renalase peptides was given either prophylactically (before) or therapeutically (after) the initiation of the disease. Samples were collected to determine early pancreatitis responses (tissue edema, plasma amylase, active zymogens) and later histologic tissue injury and inflammatory changes. In both preclinical models, renalase peptides significantly reduced histologic damage associated with pancreatitis, especially inflammation, necrosis, and overall injury. Quantifying inflammation using specific immunohistochemical markers demonstrated that renalase peptides significantly reduced overall bone marrow-derived inflammation and neutrophils and macrophage populations in both models. In the severe cerulein model, administering a renalase peptide with or without pretreatment significantly reduced injury. Pancreatitis and renalase peptide effects appeared to be the same in female and male mice. These studies suggest renalase peptides that retain the anti-inflammatory and prosurvival properties of recombinant renalase can reduce the severity of acute pancreatitis and might be attractive candidates for therapeutic development.NEW & NOTEWORTHY Renalase is a secretory protein. The prosurvival and anti-inflammatory effects of the whole molecule are contained in a 20 aa renalase site (RP220). Systemic treatment with peptides containing this renalase site reduced the severity of post-endoscopic retrograde cholangiopancreatography (ERCP) and severe cerulein pancreatitis in mouse models.

Inhibition of Monoamine Oxidases by Pyridazinobenzylpiperidine Derivatives.

Monoamine oxidase inhibitors (MAOIs) have been crucial in the search for anti-neurodegenerative medications and continued to be a vital source of molecular and mechanistic diversity. Therefore, the search for selective MAOIs is one of the main areas of current drug development. To increase the effectiveness and safety of treating Parkinson's disease, new scaffolds for reversible MAO-B inhibitors are being developed. A total of 24 pyridazinobenzylpiperidine derivatives were synthesized and evaluated for MAO. Most of the compounds showed a higher inhibition of MAO-B than of MAO-A. Compound S5 most potently inhibited MAO-B with an IC50 value of 0.203 µM, followed by S16 (IC50 = 0.979 µM). In contrast, all compounds showed weak MAO-A inhibition. Among them, S15 most potently inhibited MAO-A with an IC50 value of 3.691 µM, followed by S5 (IC50 = 3.857 µM). Compound S5 had the highest selectivity index (SI) value of 19.04 for MAO-B compared with MAO-A. Compound S5 (3-Cl) showed greater MAO-B inhibition than the other derivatives with substituents of -Cl > -OCH3 > -F > -CN > -CH3 > -Br at the 3-position. However, the 2- and 4-position showed low MAO-B inhibition, except S16 (2-CN). In addition, compounds containing two or more substituents exhibited low MAO-B inhibition. In the kinetic study, the Ki values of S5 and S16 for MAO-B were 0.155 ± 0.050 and 0.721 ± 0.074 µM, respectively, with competitive reversible-type inhibition. Additionally, in the PAMPA, both lead compounds demonstrated blood-brain barrier penetration. Furthermore, stability was demonstrated by the 2V5Z-S5 complex by pi-pi stacking with Tyr398 and Tyr326. These results suggest that S5 and S16 are potent, reversible, selective MAO-B inhibitors that can be used as potential agents for the treatment of neurological disorders.

Key Enzymes of the Serotonergic System - Tryptophan Hydroxylase 2 and Monoamine Oxidase A - In the Brain of Rats Selectively Bred for a Reaction toward Humans: Effects of Benzopentathiepin TC-2153.

At the Institute of Cytology and Genetics (Novosibirsk, Russia) for over 85 generations, gray rats have been selected for high aggression toward humans (aggressive rats) or its complete absence (tame rats). Aggressive rats are an interesting model for studying fear-induced aggression. Benzopentathiepin TC-2153 exerts an antiaggressive effect on aggressive rats and affects the serotonergic system: an important regulator of aggression. The aim of this study was to investigate effects of TC-2153 on key serotonergic-system enzymes - tryptophan hydroxylase 2 (TPH2) and monoamine oxidase A (MAOA) - in the brain of aggressive and tame rats. Either TC-2153 (10 or 20 mg/kg) or vehicle was administered once intraperitoneally to aggressive and tame male rats. TPH2 and MAOA enzymatic activities and mRNA and protein levels were assessed. The selection for high aggression resulted in upregulation of Tph2 mRNA in the midbrain, of the TPH2 protein in the hippocampus, and of proteins TPH2 and MAOA in the hypothalamus, as compared to tame rats. MAO enzymatic activity was higher in the midbrain and hippocampus of aggressive rats while TPH2 activity did not differ between the strains. The single TC-2153 administration decreased TPH2 and MAO activity in the hypothalamus and midbrain, respectively. The drug affected MAOA protein levels in the hypothalamus: upregulated them in aggressive rats and downregulated them in tame ones. Thus, this study shows profound differences in the expression and activity of key serotonergic system enzymes in the brain of rats selectively bred for either highly aggressive behavior toward humans or its absence, and the effects of benzopentathiepin TC-2153 on these enzymes may point to mechanisms of its antiaggressive action.

Synthesis, Molecular Electron Density Theory Study, Molecular Docking, and Pharmacological Evaluation of New Coumarin-Sulfonamide-Nitroindazolyl-Triazole Hybrids as Monoamine Oxidase Inhibitors.

Inhibitors of monoamine oxidases (MAOs) are of interest for the treatment of neurodegenerative disorders and other human pathologies. In this frame, the present work describes different synthetic strategies to obtain MAO inhibitors via the coupling of the aminocoumarin core with arylsulfonyl chlorides followed by copper azide-alkyne cycloaddition, leading to coumarin-sulfonamide-nitroindazolyl-triazole hybrids. The nitration position on the coumarin moiety was confirmed through nuclear magnetic resonance spectroscopy and molecular electron density theory in order to elucidate the molecular mechanism and selectivity of the electrophilic aromatic substitution reaction. The coumarin derivatives were evaluated for their inhibitory potency against monoamine oxidases and cholinesterases. Molecular docking calculations provided a rational binding mode of the best compounds in the series with MAO A and B. The work identified hybrids 14a-c as novel MAO inhibitors, with a selective action against isoform B, of potential interest to combat neurological diseases.